PEPTIDE THERAPEUTICS GROUP PLC
F-4/A, 1999-03-18
PHARMACEUTICAL PREPARATIONS
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<PAGE>
   
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MARCH 18, 1999.
    
 
   
                                                      REGISTRATION NO. 333-72077
    
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                    U.S. SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
 
   
                                AMENDMENT NO. 1
                                       TO
                                    FORM F-4
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
    
                            ------------------------
 
                         PEPTIDE THERAPEUTICS GROUP PLC
 
             (Exact name of registrant as specified in its charter)
 
                                      N/A
 
                (Translation of registrant's name into English)
 
<TABLE>
<S>                              <C>                            <C>
      ENGLAND AND WALES                      2834                     N/A
 (State or other jurisdiction    (Primary Standard Industrial   (I.R.S. Employer
              of                 Classification Code Number)     Identification
incorporation or organization)                                      Number)
</TABLE>
 
      321 CAMBRIDGE SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CB4 4WG, ENGLAND
                              011-44-1223-423-333
 
  (Address, including zip code, and telephone number, including area code, of
                   registrant's principal executive offices)
                         ------------------------------
 
                                 DR. JOHN BROWN
                                CHIEF EXECUTIVE
                         PEPTIDE THERAPEUTICS GROUP PLC
                    321 CAMBRIDGE SCIENCE PARK, MILTON ROAD
                          CAMBRIDGE, CB4 4WG, ENGLAND
                              011-44-1223-423-333
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
 
                         ------------------------------
 
                                WITH COPIES TO:
 
         MICHAEL LYTTON, ESQ.                   JOHN M. WESTCOTT, JR. ESQ.
         STANLEY KELLER, ESQ.                       HALE AND DORR LLP
         PAUL KINSELLA, ESQ.                         60 STATE STREET
          PALMER & DODGE LLP                   BOSTON, MASSACHUSETTS 02109
          ONE BEACON STREET                           (617) 526-6000
     BOSTON, MASSACHUSETTS 02108
            (617) 573-0100
 
                            ------------------------
 
   APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE OF THE SECURITIES TO THE
                                    PUBLIC:
 As soon as practicable after the Registration Statement becomes effective and
  all other conditions to the merger described in the enclosed prospectus and
                 proxy statement have been satisfied or waived.
                            ------------------------
 
    If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  / /
 
    If this form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  / /
                            ------------------------
 
   
    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933, AS AMENDED, OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO
SECTION 8(A), MAY DETERMINE.
    
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 20. INDEMNIFICATION OF DIRECTORS AND OFFICERS.
 
    Article 155 of the registrant's Articles of Association provides: "Subject
to the provisions of the Companies Acts but without prejudice to any indemnity
to which he may otherwise be entitled, every director, alternate director,
secretary, auditor or other officer of the Company shall be indemnified out of
the assets of the Company against all costs, charges, expenses, losses, damages
and liabilities incurred by him in or about the execution of his duties or the
exercise of his powers or otherwise in relation thereto including (without
prejudice to the generality of the foregoing) any liability incurred by him in
defending any proceedings, whether criminal or civil, which relate to anything
done or omitted or alleged to have been done or omitted by him as an officer or
employee of the Company in which judgment is given in his favor or in which he
is acquitted, or which are otherwise disposed of without any finding or
admission of material breach of duty on his part or in connection with any
application in which relief is granted to him by the court from liability for
negligence, default, breach of duty or breach of trust in relation to the
affairs of the Company." Pursuant to the provisions of Section 310(3) of the
Companies Act 1985 (as amended by the Companies Act 1989) the Company may
purchase and maintain insurance to indemnify any director, officer, manager or
auditor of the Company, or any company which is a member of the Group. Section
310 of the Companies Act 1985 (as amended by Section 137 of the Companies Act
1989) provides as follows:
 
    "310. Provisions exempting officers and auditors from liability
 
        (1) This section applies to any provision, whether contained in a
    company's articles or in any contract with the company or otherwise, for
    exempting any officer of the company or any person (whether an officer or
    not) employed by the company as auditor from, or indemnifying him against,
    any liability which by virtue of any rule of law would otherwise attach to
    him in respect of any negligence, default, breach of duty or breach of trust
    of which he may be guilty in relation to the company.
 
        (2) Except as provided by the following subsection, any such provision
    is void.
 
        (3) This section does not prevent a company
 
        (a) from purchasing and maintaining for any such officer or auditor
    insurance against any such liability; or
 
        (b) from indemnifying any such officer or auditor against any liability
    incurred by him;
 
        (i) in defending any proceedings (whether civil or criminal) in which
    judgment is given in his favor or he is acquitted, or
 
        (ii) in connection with any application under Section 144(3) or (4)
    (acquisition of shares by innocent nominee) or Section 727 (general power to
    grant relief in case of honest and reasonable conduct) in which relief is
    granted to him by the court."
 
    Section 727 of the Companies Act 1985 provides as follows:
 
    "727. Power of court to grant relief in certain cases
 
"(1) If in any proceedings for negligence, default, breach of duty or breach of
    trust against an officer of a company or a person employed by a company as
    auditor (whether he is or is not an officer of the company) it appears to
    the court hearing the case that that officer or person is or may be liable
    in respect of the negligence, default, breach of duty or breach of trust,
    but that he has acted honestly and reasonably, and that having regard to all
    the circumstances of the case (including those connected with his
    appointment) he ought fairly to be excused for the negligence, default,
 
                                      II-1
<PAGE>
    breach of duty or breach of trust, that court may relieve him, either wholly
    or partly, from his liability in such terms as it thinks fit.
 
(2) If any such officer or person as above-mentioned has reason to apprehend
    that any claim will or might be made against him in respect of any
    negligence, default, breach of duty or breach of trust, he may apply to the
    court for relief; and the court on the application has the same power to
    relieve him as under this section it would have had if it had been a court
    before which proceedings against that person for negligence, default, breach
    of duty or breach of trust had been brought.
 
(3) Where a case to which subsection (1) applies is being tried by a judge with
    a jury, the judge, after hearing the evidence, may, if he is satisfied that
    the defendant or defender ought in pursuance of that subsection to be
    relieved either in whole or in part from the liability sought to be enforced
    against him, withdraw the case in whole or in part from the jury and
    forthwith direct judgment to be entered for the defendant or defender on
    such terms as to costs or otherwise as the judge may think proper."
 
    These indemnification provisions may be sufficiently broad to permit
indemnification of the registrant's executive officers and directors for
liabilities arising under the Securities Act of 1933, as amended (the
"Securities Act").
 
    The registrant, with approval of the registrant's Board of Directors,
maintains director and officer liability insurance.
 
ITEM 21. EXHIBITS AND FINANCIAL STATEMENTS.
 
    (A) EXHIBITS.
 
   
<TABLE>
<CAPTION>
  EXHIBIT
  NUMBER                                                  EXHIBIT TITLE
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
       2.1   Restated Agreement and Plan of Acquisition, dated as of November 10, 1998, among Peptide Therapeutics
             Group plc, Peach Acquisition Corp. and OraVax, Inc. (attached as Annex A to the Prospectus/Proxy
             Statement included in this Registration Statement).
 
       2.2   Amendment No. 1 to Restated Agreement and Plan of Acquisition dated January 8, 1999, among Peptide
             Therapeutics Group plc, Peach Acquisition Corp. and OraVax, Inc.**
 
       2.3   Amendment No. 2 to the Restated Agreement Plan of Acquisition dated January 28, 1999, among Peptide
             Therapeutics Group plc, Peach Acquisition Corp. and OraVax, Inc. (Incorporated herein by reference to
             Amendment No. 2 to Schedule 13D filed on January 28, 1999 by Peptide Therapeutics Group plc).
 
       3.1   Memorandum and Articles of Association of Peptide Therapeutics Group plc.**
 
       5.1   Opinion of Weil, Gotshal & Manges LLP with respect to the legality of the securities registered
             hereby.**
 
      10.1   Collaboration Agreement between Peptide Therapeutics Limited and Eli Lilly and Company dated November 4,
             1998.*
 
      10.2   Option Agreement between Peptide Therapeutics Limited and the joint ventures between OraVax, Inc. and
             Pasteur Merieux Serums et Vaccins known as Pasteur Merieux OraVax S.N.C. and OraVax Merieux Co. dated
             April 27, 1998.*
 
      10.3   Collaboration Agreement between Peptide Therapeutics Limited and Peptimmune, Inc. dated March 13. 1998.*
 
      10.4   Collaborative Research and Option Agreement between Peptide Therapeutics Limited and Pfizer, Inc. dated
             December 22, 1997.*
</TABLE>
    
 
                                      II-2
<PAGE>
   
<TABLE>
<CAPTION>
  EXHIBIT
  NUMBER                                                  EXHIBIT TITLE
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
      10.5   Research and Development and License Agreement between Peptide Therapeutics Limited and SmithKline
             Beecham plc dated February 7, 1997.*
 
      10.6   Sales Agreement between Peptide Therapeutics Limited, Peptide Therapeutics Group plc, Evans Medical
             Limited and Medeva plc dated January 30, 1997.*
 
      10.7   Assignment and Variation Agreement between Peptide Therapeutics Limited, the University of Maryland at
             Baltimore and Medeva plc dated September 10, 1997.*
 
      10.8   Collaboration Agreement between Peptide Therapeutics Limited and Novartis Pharma AG dated November 1,
             1998.*
 
      10.9   Amendment No. 1 to Research and Development and License Agreement between Peptide Therapeutics Limited
             and SmithKline Beecham plc dated November 25, 1998.*
 
      10.10  Overview Agreement between Peptide Therapeutics Limited and Pasteur Merieux Serums et Vaccins S.A. dated
             January 25, 1999.*
 
      10.11  Standstill Agreement between Peptide Therapeutics Group plc and Pasteur Merieux Serums et Vaccins S.A.
             dated January 25, 1999. (Incorporated herein by reference to Amendment No. 2 to Schedule 13D filed on
             January 28, 1999 by Peptide Therapeutics Group plc.)
 
      10.12  Lease Agreement between The Master Fellows and Scholars of Trinity College Cambridge and Peptide
             Therapeutics Group plc dated May 24, 1996 with respect to Unit 329 Phase V Cambridge Science Park,
             Milton Road, Cambridge, England.**
 
      10.13  Lease Agreement among The Master Fellows and Scholars of Trinity College, Chefaro Proprietaries Limited
             and NED-INT Holdings Limited dated March 29, 1994 with respect to Unit 327 Phase V Cambridge Science
             Park, Milton Road, Cambridge, England.**
 
      10.14  Lease Agreement between The Master Fellows and Scholars of Trinity College Cambridge and IBRD Europe,
             Inc. dated April 29, 1993 with respect to Unit 324 Phase 5 Cambridge Science Park, Milton Road,
             Cambridge, England.**
 
      10.15  Lease Agreement between the Master Fellows and Scholars of Trinity College Cambridge and IBRD Europe,
             Inc. dated November 26, 1992 with respect to Unit 321 Phase 5 Cambridge Science Park, Milton Road,
             Cambridge, England.**
 
      10.16  Director's Service Agreement between Peptide Therapeutics Group plc and Nicolas Higgins dated November
             29, 1996, as amended September 18, 1998.**
 
      10.17  Director's Service Agreement between Peptide Therapeutics Group plc and Gordon Cameron dated March 1,
             1997, as amended September 18, 1998.**
 
      10.18  Director's Service Agreement between Peptide Therapeutics plc and John Brown dated March 1, 1997.**
 
      10.19  Letter of Appointment between Peptide Therapeutics Group plc and Alan Dalby dated March 25, 1998.**
 
      10.20  Letter of Appointment between Peptide Therapeutics Group plc and Alan Smith dated January 8, 1998, as
             amended April 30, 1998.**
 
      10.21  Letter of Appointment between Peptide Therapeutics Group plc and Sir Brian Richards dated March 1, 1997,
             as amended May 1, 1998.**
 
      10.22  Letter of Appointment between Peptide Therapeutics Group plc and Alan Goodman dated July 14, 1998.**
</TABLE>
    
 
   
                                      II-3
    
<PAGE>
   
<TABLE>
<CAPTION>
  EXHIBIT
  NUMBER                                                  EXHIBIT TITLE
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
      10.23  Peptide Therapeutics Group plc 1994 Unapproved Share Option Scheme.**
 
      10.24  Peptide Therapeutics Group plc 1995 Savings--Related Share Option Scheme.**
 
      10.25  Peptide Therapeutics Group plc 1995 Unapproved Share Option Scheme.**
 
      10.26  Peptide Therapeutics Group plc 1996 Approved Share Option Scheme.**
 
      10.27  Peptide Therapeutics Group plc Share Incentive Plan.**
 
      21.1   Subsidiaries of Peptide Therapeutics Group plc.**
 
      23.1   Consent of Weil, Gotshal & Manges (included as part of Exhibit 5.1).
 
      23.2   Consent of Arthur Andersen, independent auditors.**
 
      23.3   Consent of PricewaterhouseCoopers LLP, independent accountants.**
 
      23.4   Consent of Lance Gordon to serve as a director.**
 
      23.5   Consent of Hambrecht & Quist LLP.**
 
      24.1   Powers of Attorney.**
 
      99.1   Form of proxy to be mailed to stockholders of OraVax, Inc.**
</TABLE>
    
 
- ------------------------
 
   
*   Confidential treatment has been requested for the deleted portions of
    Exhibits 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9 and 10.10.
    
 
   
**  Previously filed.
    
 
    (B) FINANCIAL STATEMENT SCHEDULES.
 
        Not applicable.
 
    (C) FAIRNESS OPINION.
 
    Included in Part I as Annex B to the Prospectus/Proxy Statement contained in
this Registration Statement. Form of opinion of Hambrecht & Quist (attached as
Annex B to the included in this Registration Statement).
 
ITEM 22. UNDERTAKINGS.
 
(a) The undersigned registrant hereby undertakes:
 
(1) To file, during any period in which offers or sales are being made, a
    post-effective amendment to this registration statement:
 
(i) To include any prospectus required by Section 10(a)(3) of the Securities Act
    of 1933;
 
(ii) To reflect in the prospectus any facts or events arising after the
    effective date of the registration statement (or the most recent
    post-effective amendment thereof) which, individually or in the aggregate,
    represent a fundamental change in the information set forth in the
    registration statement. Notwithstanding the foregoing, any increase or
    decrease in volume of securities offered (if the total dollar value of
    securities offered would not exceed that which was registered) and any
    deviation from the low or high end of the estimated maximum offering range
    may be reflected in the form of prospectus filed with the Commission
    pursuant to Rule 424(b) if, in the aggregate, the changes in volume and
    price represent no more than a 20 percent change in the maximum aggregate
    offering price set forth in the "Calculation of Registration Fee" table in
    the effective registration statement;
 
                                      II-4
<PAGE>
(iii) To include any material information with respect to the plan of
    distribution not previously disclosed in the registration statement or any
    material change to such information in the registration statement.
 
(2) That, for the purpose of determining any liability under the Securities Act
    of 1933, each such post-effective amendment shall be deemed to be a new
    registration statement relating to the securities offered therein, and the
    offering of such securities at that time shall be deemed to be the initial
    BONA FIDE offering thereof.
 
(3) To remove from registration by means of a post-effective amendment any of
    the securities being registered which remain unsold at the termination of
    the offering.
 
(4) To file a post-effective amendment to the registration statement to include
    any financial statements required by Rule 3-19 of this chapter at the start
    of any delayed offering or throughout a continuous offering. Financial
    statements and information otherwise required by Section 10(a)3 of the Act
    need not be furnished, provided that the registrant includes in the
    prospectus, by means of a post-effective amendment, financial statements
    required pursuant to this paragraph (a)(4) and other information necessary
    to ensure that all other information in the prospectus is at least as
    current as the date of those financial statements.
 
(b) The undersigned registrant hereby undertakes as follows: that prior to any
    public reoffering of the securities registered hereunder through use of a
    prospectus which is a part of this registration statement, by any person or
    party who is deemed to be an underwriter within the meaning of Rule 145(c),
    the registrant undertakes that such reoffering prospectus will contain the
    information called for by the applicable registration form with respect to
    reofferings by persons who may be deemed underwriters, in addition to the
    information called for by the other Items of the applicable form.
 
(c) The undersigned registrant undertakes that every prospectus (i) that is
    filed pursuant to paragraph (a)(1) immediately proceeding, or (ii) that
    purports to meet the requirements of Section 10(a)(3) of the Act and is used
    in connection with an offering of securities subject to Rule 415, will be
    filed as a part of an amendment to the registration statement and will not
    be used until such amendment is effective, and that, for purposes of
    determining any liability under the Securities Act of 1933, as amended (the
    "Securities Act"), each such post-effective amendment shall be deemed to be
    a new registration statement relating to the securities offered therein, and
    the offering of such securities at that time shall be deemed to be the
    initial BONA FIDE offering thereof.
 
(d) The undersigned registrant hereby undertakes to respond to requests for
    information that is incorporated by reference into the Proxy
    Statement/Prospectus pursuant to Items 4, 10(b), 11 or 13 of this Form,
    within one business day of receipt of such request, and to send the
    incorporated documents by first class mail or other equally prompt means and
    (ii) to arrange or provide for a facility in the U.S. for the purpose of
    responding to such requests. This includes information contained in
    documents filed subsequent to the effective date of the registration
    statement through the date of responding to the request.
 
(e) The undersigned registrant hereby undertakes to supply by means of a
    post-effective amendment all information concerning a transaction, and the
    company being acquired involved therein, that was not the subject of and
    included in the registration statement when it became effective.
 
(f) Insofar as indemnification for liabilities arising under the Securities Act
    may be permitted to directors, officers and controlling persons of the
    registrant pursuant to the provisions discussed in Item 20 hereof, or
    otherwise, the registrant has been advised that in the opinion of the
    Commission such indemnification is against public policy as expressed in the
    Securities Act and is, therefore, unenforceable. In the event that a claim
    for indemnification against such liabilities (other
 
                                      II-5
<PAGE>
    than the payment by the registrant of expenses incurred or paid by a
    director, officer or controlling person of the registrant in the successful
    defense of any action, suit or proceeding) is asserted by such director,
    officer or controlling person in connection with the securities being
    registered hereby, the registrant will, unless in the opinion of its counsel
    the matter has been settled by controlling precedent, submit to a court of
    appropriate jurisdiction the question whether such indemnification by it is
    against public policy as expressed in the Securities Act and will be
    governed by the final adjudication of such issue.
 
                                      II-6
<PAGE>
                                   SIGNATURES
 
   
    Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant has duly caused this Amendment to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of Cambridge, England, on
March 18, 1999.
    
 
   
                                PEPTIDE THERAPEUTICS GROUP PLC
 
                                By:              /s/ JOHN R. BROWN
                                     -----------------------------------------
                                                   John R. Brown
                                                  Chief Executive
 
    
 
   
    Pursuant to the requirements of the Securities Act, this registration
statement has been signed by the following persons in the capacities and on the
dates indicated.
    
 
   
          SIGNATURE                       TITLE                    DATE
- ------------------------------  --------------------------  -------------------
 
      /s/ JOHN R. BROWN
- ------------------------------  Chief Executive (Principal    March 18, 1999
        John R. Brown             Executive Officer)
 
                                Finance Director
              *                   (Principal Financial
- ------------------------------    Officer and Chief           March 18, 1999
      Gordon B. Cameron           Accounting Officer)
 
              *
- ------------------------------  Non-Executive Chairman        March 18, 1999
       Alan G. Goodman
 
              *
- ------------------------------  Commercial Director           March 18, 1999
       Nicolas Higgins
 
              *
- ------------------------------  Non-Executive Director        March 18, 1999
          Alan Dalby
 
              *
- ------------------------------  Non-Executive Director        March 18, 1999
      Sir Brian Richards
 
              *
- ------------------------------  Non-Executive Director        March 18, 1999
          Alan Smith
 
              *
- ------------------------------  Authorized U.S.               March 18, 1999
          Alan Dalby              Representative
 
    
 
   
<TABLE>
<S>   <C>                        <C>                         <C>
*By:      /s/ JOHN R. BROWN
      -------------------------
            John R. Brown
          ATTORNEY-IN-FACT
</TABLE>
    
 
                                      II-7
<PAGE>
                                 EXHIBIT INDEX
 
   
<TABLE>
<CAPTION>
 EXHIBIT
  NUMBER                                                  EXHIBIT TITLE
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
       2.1   Restated Agreement and Plan of Acquisition, dated as of November 10, 1998, among Peptide Therapeutics
             Group plc, Peach Acquisition Corp. and OraVax, Inc. (attached as Annex A to the Prospectus/Proxy
             Statement included in this Registration Statement).
       2.2   Amendment No. 1 to Restated Agreement and Plan of Acquisition dated January 8, 1999, among Peptide
             Therapeutics Group plc, Peach Acquisition Corp. and OraVax, Inc.**
       2.3   Amendment No. 2 to Restated Agreement and Plan of Acquisition dated January 28, 1999, among Peptide
             Therapeutics Group plc, Peach Acquisition Corp. and OraVax, Inc. (Incorporated herein by reference to
             Amendment No. 2 to Schedule 13D filed on January 28, 1999 by Peptide Therapeutics Group plc.)
       3.1   Memorandum and Articles of Association of Peptide Therapeutics Group plc.**
       5.1   Opinion of Weil, Gotshal & Manges LLP with respect to the legality of the securities registered
             hereby.**
      10.1   Collaboration Agreement between Peptide Therapeutics Limited and Eli Lilly and Company dated November 4,
             1998.*
      10.2   Option Agreement between Peptide Therapeutics Limited and the joint ventures between OraVax, Inc. and
             Pasteur Merieux Serums et Vaccins known as Pasteur Merieux OraVax S.N.C. and OraVax Merieux Co. dated
             April 27, 1998.*
      10.3   Collaboration Agreement between Peptide Therapeutics Limited and Peptimmune, Inc. dated March 13. 1998.*
      10.4   Collaborative Research and Option Agreement between Peptide Therapeutics Limited and Pfizer, Inc. dated
             December 22, 1997.*
      10.5   Research and Development and License Agreement between Peptide Therapeutics Limited and SmithKline
             Beecham plc dated February 7, 1997.*
      10.6   Sales Agreement between Peptide Therapeutics Limited, Peptide Therapeutics Group plc, Evans Medical
             Limited and Medeva plc dated January 30, 1997.*
      10.7   Assignment and Variation Agreement between Peptide Therapeutics Limited, the University of Maryland at
             Baltimore and Medeva plc dated September 10, 1997.*
      10.8   Collaboration Agreement between Peptide Therapeutics Limited and Novartis Pharma AG dated November 1,
             1998.*
      10.9   Amendment No. 1 to Research and Development and License Agreement between Peptide Therapeutics Limited
             and SmithKline Beecham plc dated November 25, 1998.*
      10.10  Overview Agreement between Peptide Therapeutics Limited and Pasteur Merieux Serums et Vaccins S.A. dated
             January 25, 1999.*
      10.11  Standstill Agreement between Peptide Therapeutics Group plc and Pasteur Merieux Serums et Vaccins S.A.
             dated January 25, 1999. (Incorporated herein by reference to Amendment No. 2 to Schedule 13D filed on
             January 28, 1999 by Peptide Therapeutics Group plc.)
      10.12  Lease Agreement between The Master Fellows and Scholars of Trinity College Cambridge and Peptide
             Therapeutics Group plc dated May 24, 1996 with respect to Unit 329 Phase V Cambridge Science Park,
             Milton Road, Cambridge, England.**
      10.13  Lease Agreement among The Master Fellows and Scholars of Trinity College, Chefaro Proprietaries Limited
             and NED-INT Holdings Limited dated March 29, 1994 with respect to Unit 327 Phase V Cambridge Science
             Park, Milton Road, Cambridge, England.**
      10.14  Lease Agreement between The Master Fellows and Scholars of Trinity College Cambridge and IBRD Europe,
             Inc. dated April 29, 1993 with respect to Unit 324 Phase 5 Cambridge Science Park, Milton Road,
             Cambridge, England.**
      10.15  Lease Agreement between the Master Fellows and Scholars of Trinity College Cambridge and IBRD Europe,
             Inc. dated November 26, 1992 with respect to Unit 321 Phase 5 Cambridge Science Park, Milton Road,
             Cambridge, England.**
      10.16  Director's Service Agreement between Peptide Therapeutics Group plc and Nicolas Higgins dated November
             29, 1996, as amended September 18, 1998.**
</TABLE>
    
<PAGE>
   
<TABLE>
<CAPTION>
 EXHIBIT
  NUMBER                                                  EXHIBIT TITLE
- -----------  --------------------------------------------------------------------------------------------------------
<C>          <S>
      10.17  Director's Service Agreement between Peptide Therapeutics Group plc and Gordon Cameron dated March 1,
             1997, as amended September 18, 1998.**
      10.18  Director's Service Agreement between Peptide Therapeutics plc and John Brown dated March 1, 1997.**
      10.19  Letter of Appointment between Peptide Therapeutics Group plc and Alan Dalby dated March 25, 1998.**
      10.20  Letter of Appointment between Peptide Therapeutics Group plc and Alan Smith dated January 8, 1998, as
             amended April 30, 1998.**
      10.21  Letter of Appointment between Peptide Therapeutics Group plc and Sir Brian Richards dated March 1, 1997,
             as amended May 1, 1998.**
      10.22  Letter of Appointment between Peptide Therapeutics Group plc and Alan Goodman dated July 14, 1998.**
      10.23  Peptide Therapeutics Group plc 1994 Unapproved Share Option Scheme.**
      10.24  Peptide Therapeutics Group plc 1995 Savings-Related Share Option Scheme.**
      10.25  Peptide Therapeutics Group plc 1995 Unapproved Share Option Scheme.**
      10.26  Peptide Therapeutics Group plc 1996 Approved Share Option Scheme.**
      10.27  Peptide Therapeutics Group plc Share Incentive Plan.**
      21.1   Subsidiaries of Peptide.**
      23.1   Consent of Weil, Gotshal & Manges (included as part of Exhibit 5.1).
      23.2   Consent of Arthur Andersen, independent auditors.**
      23.3   Consent of PricewaterhouseCoopers LLP, independent accountants.**
      23.4   Consent of Lance Gordon to serve as a director.**
      23.5   Consent of Hambrecht & Quist LLP.**
      24.1   Powers of Attorney.**
      99.1   Form of proxy to be mailed to stockholders of OraVax, Inc.**
</TABLE>
    
 
- ------------------------
 
   
*   Confidential treatment has been requested for the deleted portions of
    Exhibits 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9 and 10.10.
    
 
   
**  Previously filed.
    

<PAGE>


                                                                    EXHIBIT 10.1


                             DATED November 4, 1998
                             ----------------------


                          PEPTIDE THERAPEUTICS LIMITED

                                     - and -

                              ELI LILLY AND COMPANY


- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------


                             COLLABORATION AGREEMENT


- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------



<PAGE>



                                    AGREEMENT



      This agreement is made on November 4, 1998 between PEPTIDE THERAPEUTICS
LIMITED (No. 2774777) whose registered office is at 321 Cambridge Science Park,
Milton Road, Cambridge, CB4 4WG, United
Kingdom ("Peptide")

                                       and

ELI LILLY AND COMPANY whose registered office is at Lilly Corporate Center,
Indianapolis, Indiana 46285, USA ("Lilly").

      Together referred to as "the Parties".

WHEREAS:

      (A)   Peptide has developed a system for the discovery of substrates and
            the development of inhibitors of protease enzymes known as RAPiD
            (Rational Approach to Protease Inhibitor Design);

      (B)   Lilly has a potential interest in acquiring rights to the RAPiD
            technology and, prior to entering into such a transaction wishes to
            evaluate the technology by carrying out a pilot study;

      (C)   In order to carry out the pilot study, Lilly has identified four
            Target Proteases for which Peptide will use its RAPiD technology to
            develop FRET based Substrates;

      (D)   Following successful completion of the Programme and written 
            notice by Lilly prior to []* to Peptide of its desire to enter 
            into a Technology Transfer Agreement, the Parties shall negotiate 
            in good faith a Technology Transfer Agreement.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

IT IS AGREED as follows:

1.    DEFINITIONS

      1.1   "Arising IP" means any Intellectual Property resulting from the
            Programme carried out by Peptide including the Data.

      1.2   "Background IP" means all Intellectual Property owned by either
            party prior to this Agreement or generated during the term of this
            Agreement but not resulting from the Programme. For the avoidance of
            doubt, the Parties recognize that Lilly owns all Intellectual
            Property related to the Target Proteases and Peptide owns all
            Intellectual Property related to RAPiD.

      1.3   "Control Protease" means one of the Target Proteases that Lilly
            chooses to use as a control in the Programme.

      1.4   "Data" means the data relating to the Target Proteases generated
            during the Programme by Peptide.

      1.5   "FRET" means Fluorescence Resonance Energy Transfer.

      1.6   "Know How" means all technical and scientific
            information necessary or useful in developing Substrates not at
            present in the public domain held in any form (including, without
            limitation, that comprised in or derived from drawings, data,
            formulae, specifications, notes, chemical compounds, computer
            software, component lists, instructions, manuals, reports and
            process descriptions).

      1.7   "Intellectual Property" means any and all interest, whether legal or
            beneficial, arising under the laws of England or elsewhere in
            patent, copyright, design right, rights in confidentiality, trade
            mark rights and any other analogous rights, applications for any of
            the foregoing (and the right to make such applications) including
            Know How.

      1.8   "Press Release" means the press release to be released by Peptide on
            the signing of this Agreement as set out in Addendum III

      1.9   "Programme" means a programme of work whereby Peptide will apply
            RAPiD to each of the four Target Proteases supplied by Lilly as set
            out in more detail in Addendum II. The purpose of the Programme is
            to identify a Substrate for each Target Protease.


<PAGE>

      1.10  "RAPiD" means Peptide's proprietary system for discovering
            substrates and developing inhibitors of protease enzymes.

      1.11  "Report" means a report summarizing the Data for all the Target
            Proteases to be provided by Peptide to Lilly.

      1.12  "Substrate" means a FRET substrate for a Target
            Protease

      1.13  "Target Proteases" means up to four proteases to be supplied by
            Lilly to Peptide.

      1.14  "Technology Transfer Agreement" means the agreement to be entered
            into by the Parties allowing for the transfer of the RAPiD
            technology by Peptide to Lilly consistent with the terms described
            in Addendum I and other terms which are customary under similar
            circumstances.


2.    THE PROGRAMME

      2.1   As soon as reasonably practicable following signing this Agreement,
            Lilly shall provide Peptide with sufficient quantity of each of the
            Target Proteases required for the Programme and any information
            necessary or useful for the assay of each of the Target Proteases.

      2.2   Peptide agrees to use reasonable endeavours to carry out the
            Programme and to deliver to Lilly the Report and the Data for each
            of the Target Proteases by []* or as soon as is reasonably 
            practicable. In addition, if Peptide has identified a FRET 
            Substrate for any of the Target Proteases, Peptide will supply 
            Lilly with approximately 10 mg of such Substrate for evaluation 
            by Lilly. If the generic library does not give a hit for a Target 
            Protease, then Peptide shall still supply any Data to Lilly for 
            evaluation.

      2.3   Lilly, at its sole option, may enter into a Technology Transfer
            Agreement with Peptide by providing Peptide with notice of the same
            at any time during the Option Period pursuant to terms negotiated by
            the parties in good faith that are consistent with the terms
            described in Addendum I and other terms that are customary under
            similar circumstances. For purposes of this Agreement the term
            "Option Period" shall mean the period commencing on the effective
            date of this

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

            Agreement and ending on the []*

3.    CONSIDERATION

      In consideration of Peptide carrying out the Programme, Lilly agrees to
      make payments to Peptide after signing this Agreement, exclusive of any
      applicable sales taxes in the following manner: 

         []*

       Notwithstanding anything to the contrary in this Agreement, under no
       circumstance shall Lilly make payments to Peptide under this Agreement in
       excess of

         []*

4.    INTELLECTUAL PROPERTY

      4.1   All Background IP shall remain the property of the party owning such
            Background IP prior to this Agreement.

      4.2   All Arising IP, all Data and any Substrates shall be the property of
            Peptide.

      4.3   Lilly shall have an []* license for Arising IP, Data and Substrate 
            relating to each Target Protease that it has paid the []* license 
            fee for under 3, above.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

      4.4   Peptide shall, at the request of Lilly, file any patent applications
            covering Arising IP at Lilly's cost. Such patent applications shall
            be filed in the name of Peptide and shall form part of the license
            to Lilly in 4.3 above.

      4.5   If Lilly does not exercise its option to take a license under 3
            (iii) above for a Target Protease then Lilly shall have no rights to
            use any of the Arising IP, Data or Substrate for that Target
            Protease at any time for any purpose whatsoever.

5.    CONFIDENTIALITY

      The Parties hereby acknowledge that the Confidentiality Agreement dated
      September 3, 1998 entered into between the Parties covers all aspects of
      the handling of Confidential Information anticipated by this Agreement.
      Background IP, Arising IP and Data shall be included as Confidential
      Information.

6.    WARRANTIES AND UNDERTAKINGS

      The Parties exclude to the fullest extent permitted by law any warranties,
      conditions, undertakings or terms implied by operation of law (statutory
      or otherwise).

7.    ASSIGNMENT

      Neither party shall assign or transfer or purport to assign or transfer
      any of its rights or obligations under this Agreement except with the
      prior written consent of the other party save that either party may at any
      time assign or transfer any of its rights or obligations under this
      Agreement to any of its Affiliates. Affiliates for the purpose of this
      Agreement shall mean any entity Controlled by such party. Controlled shall
      mean direct or indirect beneficial ownership of fifty percent (50%) or
      more of the voting income or equity interest in a business entity. This
      Agreement shall be binding upon and shall inure to the benefit of the
      Parties hereto, their successors and assigns.

8.    COSTS


<PAGE>

      Except as otherwise expressly provided in this Agreement, each party shall
      pay its own costs of and incidentals to the negotiation, preparation,
      execution and implementation by it of this Agreement and of all other
      documents referred to in it.

9.    FURTHER ASSURANCE

      Each party shall, at its own cost, do and execute or procure to be done
      and executed all necessary acts, deeds, documents and things reasonably
      within its power to give effect to this Agreement.

10.   GENERAL

      10.1  This Agreement constitutes the entire agreement between the Parties
            relating to the subject matter of this Agreement (except for the
            Confidentiality Agreement dated September 3, 1998) and supersedes
            all previous such agreements whether made orally or in writing.

      10.2  No variation of this Agreement shall be valid unless it is in
            writing and signed by or on behalf of each of the Parties.

      10.3  The failure to exercise or delay in exercising right or remedy under
            this Agreement shall not constitute a waiver of the right or remedy
            or a waiver of any other rights or remedies and no single or partial
            exercise of any right or remedy under this Agreement shall prevent
            any further exercise of the right or remedy or the exercise of any
            other right or remedy.

      10.4  Nothing in this Agreement shall be construed as creating a
            partnership between the Parties or as constituting either party as
            the agent of the other party for any purpose whatsoever and neither
            party shall have the authority or power to bind the other party or
            to contract in the name of or create a liability against the other
            party in any way or for any purpose.

      10.5  If the performance of any part of this Agreement by either party, or
            of any obligation under this Agreement, is prevented, restricted,
            interfered with or delayed by reason of any cause beyond the control
            of the party liable to perform, unless conclusive evidence to the
            contrary is


<PAGE>

            provided, the party so affected shall, upon giving written notice to
            the other party, be excused from such performance to the extent of
            such prevention, restriction, interference or delay, provided that
            the affected party shall use its best efforts to avoid or remove
            such causes of non-performance and shall continue performance with
            the utmost dispatch whenever such causes are removed. When such
            circumstances arise, the Parties shall discuss what, if any,
            modification of the terms of this Agreement may be required in order
            to arrive at an equitable solution.

11.   GOVERNING LAW AND JURISDICTION

      This Agreement shall be governed by the laws of England and the Parties
      hereto hereby irrevocably submit to the non-exclusive jurisdiction of the
      English Courts.

12.   COUNTERPARTS

      This Agreement may be executed in any number of counterparts each of
      which, when executed and delivered, shall be an original, but all the
      counterparts together shall constitute one and the same instrument.

13.   TERM 

      []*

14.     ANNOUNCEMENTS

The Parties agree that immediately following the execution of this Agreement the
Press Release may be released by Peptide. No other public announcement,
communication or circular (other than to the extent required by law, the London
Stock Exchange Limited or the panel on take-overs and mergers or any other
regulatory body in any jurisdiction) concerning the transactions referred to in
this Agreement shall be made or dispatched by either party for so long as this
Agreement continues in force without the prior written consent of the other
party, such consent not to be unreasonably withheld or delayed.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>

      IN WITNESS WHEREOF, the Parties, through their authorized officers, have
executed this Agreement as of the date first written above.


PEPTIDE THERAPEUTICS LIMITED

By: /s/ Nicolas Higgins
   ------------------------------
Name: Nicolas A. Higgins
     ----------------------------
Title: Commerical Director
      ---------------------------


ELI LILLY AND COMPANY

By: /s/ [ILLEGIBLE]
   ------------------------------
Name: [ILLEGIBLE]
     ----------------------------
Title: November 4, 1998
      ---------------------------

<PAGE>


                                   Addendum I *



[]*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.




<PAGE>


                                   Addendum II

                                 Work Programme

[]*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>


                                  Addendum III

                                The Press Release


                         Peptide Therapeutics Group plc

  Collaboration with Eli Lilly on development of protease inhibitors


Peptide Therapeutics Group plc ("Peptide") (Cambridge, UK) announces that it has
entered into a research collaboration with Eli Lilly and Company ("Lilly")
(Indianapolis, USA). Under the terms of the agreement, Peptide will apply its
proprietary `RAPiD' protease inhibitor drug discovery technology to four
protease targets provided by Lilly.

John Brown, CEO of Peptide said "We are delighted to be working with such a
significant corporate partner as Lilly. RAPiD is already being applied to
several in-house and collaborative programmes and the addition of Lilly as
another partner provides further endorsement of the technology's potential."


Enquiries:

Peptide Therapeutics Group plc                  Tel: 01223 423333
Dr John Brown, CEO
Financial Dynamics                              Tel: 0171 831 3113
John Bick



NOTES TO EDITORS

1.    RAPiD

Peptide's proprietary RAPiD (Rational Approach to Protease Inhibitor Design)
technology exploits novel combinatorial and medicinal chemistry techniques, and
enables the rapid development of potent and selective protease inhibitor drugs.
RAPiD can be applied to all classes of proteases and, in addition to inhibitors,
also provides substrates (suitable for high throughput screening), a wealth of
structure activity relationship data for the protease, and probe inhibitors for
drug target validation.

Peptide is applying its RAPiD technology internally to develop protease
inhibitor drugs for several diseases but is also commercialising the technology
through collaborations with pharmaceutical companies.

2.    Peptide

Peptide is a biopharmaceutical development company based in Cambridge, UK.
Peptide's strategy is to discover novel drugs and vaccines using innovative
proprietary


<PAGE>

technologies and to develop these products through royalty-bearing alliances
with leading pharmaceutical companies who will then complete the development and
manufacture and market the product.



<PAGE>


                                                                   EXHIBIT 10.2


                                  [LETTERHEAD]


April 27, 1998


By telefax: 011 44 1223 423 111

Mr. N.A. Higgins
Peptide Therapeutics Limited
321 Cambridge Science Park
Milton Road
Cambridge CB4 4WG
England

Dear Nick:

This letter is intended to outline the general terms which have been agreed
between Peptide Therapeutics ("PT") and the joint ventures between OraVax, Inc.
and Pasteur Merieux Serums et Vaccins S.A. known as Merieux OraVax S.N.C. and
OraVax Merieux Co. ("PM-O").

This letter provides for terms and conditions of an option granted by PT to PM-O
in order to allow PM-O to evaluate the technical feasibility of H. pylori
vaccines formulated with PT's Salmonella vectors. For this part, this letter is
hereinafter referred to as the "Option Agreement."

This letter also expresses the intent of the parties to negotiate in good faith
a license agreement to be executed by their authorized representatives. Under
the license agreement, PM-O will obtain rights to develop and commercialize H.
pylori vaccines formulated with any PT's Salmonella vector (the "PT
Technology"). Until []* PT will negotiate exclusively with PM-O regarding the
use of the PT Technology with the PM-O program H. pylori antigens, and
non-exclusively regarding the use of the PT Technology for all other H. pylori
antigens.

Option Agreement

                                                                                
                                                                                
Option Period       []*

Option              PT will grant to PM-O an exclusive option to an exclusive,
                    worldwide license to PT's Salmonella Technology for the
                    development, manufacture, use and/or sale of prophylactic
                    and therapeutic human vaccines against H. pylori infection,
                    under a License Agreement containing the terms set out below


- ----------------
*   This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>


Feasibility         Study The parties will perform a joint Feasibility Study to
                    evaluate the utility of the PT technology in PM-O's H.
                    pylori vaccines in two stages as described in Attachments A
                    and B.

Option Fee          PM-O will pay PT a non-refundable Option Fee of
                    []* , in three installments, subject to the following:

                    []* on execution of this Option Agreement
                    []* on successful completion by PT of items 1-5 of 
                    Attachment A. In the event PT can not successfully 
                    complete items 1-5 of Attachment A, this second 
                    installment shall not be payable by PM-O, and the parties 
                    will have the option to not proceed with items 6 and 7 of 
                    Attachment A and item 3 of Attachment B.
                    []* in the event the parties elect to proceed with 
                    items 6 and 7 of Attachment A and item 3 of Attachment B 
                    and on completion by PT of step 7 of Attachment A

                    The parties will keep each other informed of their
                    activities under the Feasibilty Study and report the results
                    of their work to each other in a timely manner.

Reporting           PM-O will inform PT on or before thirty (30) days after the
                    termination of the Option of its decision whether or not to
                    proceed with commercial development of PT's technology under
                    the License Agreement terms proposed below.

Exercise of Option  In the event PM-O elects to proceed with commercial 
                    development of PT's technology, the parties will enter into
                    a License Agreement containing the terms set out below, 
                    such License Agreement to be entered into by the parties 
                    []*. In the event PM-O declines to proceed with commercial
                    development, the Option Agreement shall be terminated and
                    all PT patent rights will revert to PT.

Confidentiality     During the term of the Option Period any confidential
                    information received by one party from the other party shall
                    be governed by the terms of the Confidential Disclosure
                    Agreement between PT and PM-O dated May 8, 1997, save that
                    PM-O and PT shall have the right to use and disclose to
                    third parties data and results from the Feasibility Study
                    solely for research and development activities relating to
                    the other party's technology, provided such disclosure is
                    made under obligations of confidentiality similar to those
                    of the aforementioned Confidential Disclosure Agreement
                    between PT and PM-O.


- -----------------
*   This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       2

<PAGE>

License Agreement

Grant               PT will grant to PM-O an exclusive license for human
                    applications to its Salmonella typhimurium and Salmonella
                    typhi vectors and all related patents, patent applications
                    and know-how (the "PT technology"), the right to sublicense,
                    for use with the PM-O program H. pylori antigens, and a
                    non-exclusive license regarding the use of the PT technology
                    for all other H. pylori antigens.

Territory           Worldwide

Term                The term of the license will be []*

PM-O Diligence      PM-O will exert reasonable efforts to develop and introduce
requirements        the PT technology into the commercial market.

Royalty             PM-O will pay to PT []* royalties on net sales of licensed
                    products (whether by PM-O or any licensee); in the event
                    PM-O is required to license other third party technologies,
                    this rate may be reduced by []* of royalties due to such
                    third parties, but in no event will the rate payable by PM-O
                    be reduced to less than (i) []* if the PT technology is
                    the only adjuvant or delivery system required to
                    commercialize a licensed product; (ii) []* if PM-O is
                    required to license other adjuvant or delivery system
                    technologies in order to commercialize a licensed product;
                    (iii) []* if PT know-how only is used by PM-O to
                    commercialize a licensed product. []*

License Fee         On execution of the License Agreement, PM-O will pay PT a
                    non-refundable signing fee of []*.


Milestone payments  PM-O will pay to PT the following milestone payments:

                     []*

- ----------------
*   This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       3
<PAGE>


                    []*

                    []*

General             If the parties agree that PT should provide additional
                    services (such as process development/manufacturing of
                    clinical lots, toll manufacture, etc.), then the parties
                    agree to negotiate additional payments to reflect this added
                    input by PT.

Governing Law       Option and License Agreement to be under English law and
                    jurisdiction.


Please indicate Peptide Therapeutics agreement to the terms set out below in the
space provided below.



 /s/ Lance K. Gordon                        /s/ Paul Kirkconnell
- ------------------------------------       ------------------------------------
Lance K. Gordon, Ph.D.                     Paul Kirkconnell
OraVax Merieux Co.                         Merieux OraVax S.N.C.



 /s/ Nicolas Higgins
- ------------------------------------
Nicolas Higgins
Director
Peptide Therapeutics Limited



- -----------------
*   This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                      4
<PAGE>



                                  ATTACHMENT A


                                  CONFIDENTIAL

                     Feasibility Study for H. pylori Vaccine
                          Peptide Therapeutics Workplan

                                                                                
[]* 












- ------------------
*   This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                     5
<PAGE>




                                  ATTACHMENT B

                                  CONFIDENTIAL

                     Feasibility Study for H. pylori Vaccine
                                 PM-O Workscope

[]*








- -----------------
*   This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                     6

<PAGE>


                                                                    EXHIBIT 10.3


                               DATED MARCH 13, 1998

                          PEPTIDE THERAPEUTICS LIMITED

                                       and

                                 PEPTIMMUNE INC.

                            COLLABORATION AGREEMENT


<PAGE>

                                        1


THIS AGREEMENT is made on March 13, 1998

BETWEEN:

(1)   PEPTIDE THERAPEUTICS LIMITED, a company incorporated in England and Wales
      (registered no.2774777), whose registered office is at 321 Cambridge
      Science Park, Milton Road, Cambridge CB4 4WG ("PT"); and

(2)   PEPTIMMUNE INC., a company incorporated in Delaware whose registered
      office is at 840 Memorial Drive, Cambridge, MA 02139-3771 USA ("PI"),
      together referred to as "the Parties".

WHEREAS:

(A)   PT has developed the RAPiD(TM) (Rational Approach to Protease Inhibitor
      Design) technology to enable the RAPiD development of protease inhibitors;

(B)   PI has determined that inhibition of Cathepsin S is a suitable way to
      suppress the class II MHC-associated immune response in mammals.
      Inhibition of Cathepsin S is therefore considered an appropriate method
      for the treatment of autoimmune diseases, allergic responses and organ
      transplant or tissue graft rejection. A patent application in this field
      has been submitted by the Massachusetts Institute of Technology ("MIT").
      PI is the exclusive licensee under an Agreement with MIT dated May 5,
      1997, and as amended March 13,1998, a copy of which is attached at
      Schedule 3 (the "MIT Agreement"). []*

(C)   PT and PI have agreed to establish a collaboration to use RAPiD(TM) to
      develop inhibitors for Cathepsin S and to commercialise these inhibitors.

THIS AGREEMENT WITNESSES as follows:

1.   INTERPRETATION

1.1. In this Agreement:

      "Affiliate"            means any company or other entity which directly or
                             indirectly owns, is owned by or is under common
                             ownership with a Party to this Agreement to the
                             extent of at least fifty percent (50%) of the
                             equity (or such lesser percentage which is the
                             maximum allowed to be owned by a foreign
                             corporation in a


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



<PAGE>

                                        2

                             particular jurisdiction) having the power to vote
                             on or direct the affairs of the entity and any
                             person, firm, company or other entity actually
                             controlled by, controlling or under common control
                             with a Party to this Agreement.

      "Effective Date"       means the date of execution of this Agreement.

      "Field"                means Cathepsin S inhibitors for use in the
                             treatment of autoimmune and allergic diseases and
                             to prevent organ transplant and tissue graft
                             rejection.

      "Intellectual          means patents, patent applications, trade marks,
       Property"             service marks, registered designs, applications for
                             any of the foregoing; trade and business names,
                             unregistered trade marks and service marks,
                             copyrights, rights in designs, Inventions, rights
                             under licences, consents, orders, statutes or
                             otherwise howsoever in relation to any such rights,
                             and rights of the same or similar effect or nature,
                             in any part of the world.

      "Invention"            means innovative patentable subject matter and
                             shall include both subject matter capable of such
                             exploitation under intellectual property rights and
                             subject matter capable of such exploitation by
                             reasons of its confidential nature and, without
                             prejudice to the generality of the foregoing, the
                             said expression shall include computer software,
                             biological material and plant varieties.

      "Inventors"            means persons who devise Inventions and shall
                             include both authors of computer software and
                             authors of any copyright material relevant to an
                             Invention.

      "Know-How"             means all non-patentable technical and scientific
                             information necessary or useful in practising PI
                             Rights or PT Rights not at present in the public
                             domain held in any form (including, without
                             limitation, that comprised in or derived from
                             drawings, data, formulae, specifications, notes,
                             chemical compounds, computer software, component
                             lists, instructions, manuals, technical brochures,
                             catalogues and process descriptions).
<PAGE>

                                        3

      "PI Rights"            all rights in any Intellectual Property or
                             Know-how owned or controlled by or at the free
                             disposal of PI, other than the MIT Agreement, or
                             any Affiliate of PI at the date of this Agreement
                             which relate to Cathepsin S and the Project.

      "Project"              means the programme of research and development to
                             be carried out by PT and PI as more particularly
                             described in the Work Programme.

      "Project Rights"       means rights in any Inventions, Intellectual
                             Property or Know How within the Field arising from
                             the Project or work done on or in connection with
                             the Project. For avoidance of doubt, Project Rights
                             shall not include PT Rights or PI Rights.

      "PT Rights"            all rights in any Intellectual Property or Know-how
                             owned or controlled by or at the free disposal of
                             PT or any Affiliate of PT at the date of this
                             Agreement and relating to RAPiD(TM) and its
                             associated technologies which relate to the
                             Project.

      "Revenue"              means all consideration actually received net of
                             any and all royalties, milestone, licence fee and
                             other similar payments for patent and or
                             intellectual property use rights necessary to the
                             commercialisation of the Project Rights payable to
                             third parties, who are not Affiliates, by either or
                             both of the Parties from third parties which result
                             from the commercialisation of the Project Rights
                             (including without limitation development funds,
                             payments for options for licences, paid up
                             licences, stage payments under licences, milestone
                             payments and royalties). The payment of
                             consideration in the form of anything other than
                             cash payments shall only be permitted with the
                             express written consent of both Parties unless one
                             of the Parties is no longer a Party to this
                             Agreement.

      "Work Programme"       means the programme of work as set out at Schedule
                             1.


 1.2. In this Agreement, a statutory provision includes a reference to:

      1.2.1 (a) the statutory provision as modified or re-enacted or both from
            time to
<PAGE>

                                        4

            time before the date of this Agreement; and

            (b) any subordinate legislation made under the statutory provision
                before the date of this Agreement;

      1.2.2 persons includes a reference to any body corporate, unincorporated
            association or partnership;

      1.2.3 a person includes a reference to that person's legal personal
            representatives, successors and permitted assigns;

      1.2.4 a Clause or Schedule, unless the context otherwise requires, is a
            reference to a clause of or schedule to this Agreement and the
            Schedules shall form an integral part of this Agreement;

 1.3. The headings in this Agreement shall not affect the interpretation of this
      Agreement.

 2.   THE PROJECT

 2.1. The Parties shall diligently carry out the Project and shall procure that
      the Project is carried out by suitably qualified staff.

 2.2. Neither Party shall sub-contract any work on the Project without the prior
      written consent of the other Party. As at the Effective Date, it is agreed
      that PI will subcontract all animal studies necessary to establish
      biological proof-of-principle as identified in Clause 2.5.

 2.3. PT and PI shall set up a Project Management Team. This team will consist
      of both scientific and commercial representatives of both PT and PI. The
      role of the Project Management Team shall be to co-ordinate the
      collaboration and to manage the day-to-day running of the Project. The
      Project Management Team shall not go beyond the limits of the Project as
      set out in this Agreement and shall have no authority to bind the Parties
      with respect to any obligations to third parties nor to incur any costs
      beyond those contained in budgets approved by the Parties without the
      prior written agreement of the Parties.

 2.4. Within one month of the Effective Date the Project Management Team shall
      meet and shall agree to the major milestones of the Project together with
      the time limits and budgets for achievement of these milestones. If the
      Parties are unable to reach such agreement within 30 days then the
      Agreement shall terminate.
<PAGE>

                                        5

 2.5. The Project will aim to illustrate []*

 2.6. PT and PI shall each provide research reports to each other on a monthly
      basis. These reports shall detail progress made in the Project in the
      previous month. The Project Management Team shall meet at least every
      three months to review progress of the Project and to determine strategy
      for the development of the Project.

 2.7. Each Party shall bear its own costs for its part in the Project. Each
      Party shall keep account of its costs on the basis defined at Schedule 2
      hereto and shall produce an accounting on a quarterly basis. It is the
      intent of the Parties that each Party shall bear approximately 50% of the
      costs of the Project.

 2.8. For the avoidance of doubt, all persons employed or appointed as
      subcontractors or agents by either Party on the Project, shall remain the
      sole responsibility of that Party and that Party shall remain liable for
      the payment of the salaries and fees (and all taxation and other
      contributions payable thereon) of such persons.

 2.9. Neither Party shall work on the development of inhibitors of Cathepsin S
      in collaboration with or at the request of or on behalf of any third party
      until termination of this Agreement.

 3.   TERMINATION

 3.1. Either Party (the "Initiating Party") may terminate this Agreement with
      immediate effect by notice in writing to the other Party (the "Defaulting
      Party") on or at any time after the occurrence of any of the events
      specified in Clause 3.2 in relation to the Defaulting Party.



- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



<PAGE>

                                        6

 3.2. The events are:

      3.2.1 a material breach by the Defaulting Party of any of its material
            obligations under this Agreement which (if the breach is capable of
            remedy) the Defaulting Party has failed to remedy within 120 days
            after receipt of notice in writing from the Initiating Party
            identifying the breach and requiring the Defaulting Party to remedy
            the breach; or

      3.2.2 the passing by the Defaulting Party of a resolution (or similar) for
            its winding-up or the making by a court of competent jurisdiction of
            an order (or similar) for the winding-up of the Defaulting Party or
            the dissolution of the Defaulting Party (other than for the purposes
            of corporate restructuring); or

      3.2.3 the making of an administration order (or similar) in relation to
            the Defaulting Party or the appointment of a receiver (or similar
            officer) over, or the taking of possession or sale by an
            encumbrancer of, any of the Defaulting Party's assets; or

      3.2.4 the Defaulting Party making an arrangement or composition with its
            creditors generally or making an application to a court of competent
            jurisdiction for protection from its creditors generally; or

      3.2.5 the Defaulting Party ceasing, or threatening to cease, to carry on
            all or substantially all of its business activities.

 4.   CONSEQUENCES OF TERMINATION

 4.1. All rights and obligations of the Parties shall cease to have effect
      immediately upon termination of this Agreement except that termination
      shall not affect:

      4.1.1 the accrued rights and obligations of the Parties at the date of
            termination; and

      4.1.2 the continued existence and validity of the rights and obligations
            of the Parties under Clauses 4.3, 4.4, 4.5, 6.1, 6.2, 6.5, 6.6, 6.9,
            6.14, and 7 and the provisions set out in Schedule 1 and any
            provisions of this Agreement necessary for the interpretation or
            enforcement of this Agreement

      and if termination of this Agreement is pursuant to Clause 3.2 above then
      the Party not in breach shall be free to continue the Project alone or
      with a third party and the Defaulting Party shall automatically assign its
      rights in the Project Rights to the other Party at no cost and shall grant
      to the other Party perpetual, royalty free, non-exclusive licences (with
      rights to sub-license) to PI Rights (where PI is
<PAGE>

                                        7

      the Defaulting Party) or to PT Rights (where PT is the Defaulting Party).

 4.2. If the Parties agree that the objectives of the Project cannot be met
      within the agreed timescale referred to in Clause 2.5 of this Agreement or
      the objectives of the Project have not been met within 24 months of the
      Effective Date then this Agreement shall immediately terminate.

      4.2.1 PT shall own all PT Rights and Project Rights which are improvements
            to or extensions of RAPiD including compound libraries.

      4.2.2 PI shall own all PI Rights and Project Rights which are improvements
            to or extensions of PI Rights.

      4.2.3 Any Inventions and Intellectual Property related to pharmacophores,
            compounds and inhibitors of Cathepsin S generated as a result of the
            Project shall be jointly assigned to PT and PI pursuant to Clause 6.

 4.3. In the event of the termination of this Agreement, other than pursuant to
      Clause 2.4 or 4.2, then the Defaulting Party shall receive a percentage
      share of any Revenue generated by the other Party such a share being
      calculated on the following basis:

      4.3.1 If the Agreement is terminated prior to the first anniversary of the
            Effective Date, then the Defaulting Party's share shall be []*

      4.3.2 If the Agreement is terminated after the first anniversary of the
            Effective Date but before any Cathepsin S inhibitors undergo
            toxicology studies then the Defaulting Party's share shall be []*

      4.3.3 if the Agreement is terminated after one or more Cathepsin S
            inhibitors has entered toxicology studies but before approval to
            begin human clinical studies then the Defaulting Party's share shall
            be []*

      4.3.4 if the Agreement is terminated after one or more Cathepsin S
            inhibitors receives approval to begin human clinical studies then
            the Defaulting Party's share shall be []*

      The Defaulting Party will continue to receive such a Revenue share for the
      period of []*

 4.4. []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>

                                        8

      []*

 4.5  In the case of PT being the Defaulting Party, PT agrees not compete with
      PI in the Field for a period of one (1) year following the termination of
      the Agreement.


 5.   WARRANTIES AND UNDERTAKINGS

 5.1. PI hereby represents, warrants and undertakes to PT that:

      5.1.1 All of PI's employees are subject to strict confidentiality
            obligations and all discoveries, Inventions and Intellectual
            Property made by employees during the course of his/her employment
            by PI are owned absolutely by PI;

      5.1.2 The terms of all contracts for the provision of services to PI by
            independent contractors contain provisions whereby the contractor is
            subject to strict confidentiality obligations and all discoveries,
            Inventions and Intellectual Property in the Field made by the
            independent contractor in performing the service contracted for are
            owned absolutely by PI []*;

      5.1.3 PI shall, at the Effective Date, have obtained all necessary
            consents and permissions from MIT as may be required under the MIT
            Agreement in order for PI to be able to enter into and perform its
            obligations under this Agreement and sub-license PI Rights to PT and
            to any third parties;

      5.1.4 at the Effective Date PI is not aware of any royalties or other
            payments which are or may become payable to third parties in respect
            of the PI Rights with the exception of the MIT Agreement.

 5.2. PT hereby represents, warrants and undertakes to PI that:

      5.2.1 the employment contracts of all of PI's employees contain provisions
            whereby the employee is subject to strict confidentiality
            obligations and all discoveries, Inventions and Intellectual
            Property made by the employee during the course of his/her
            employment by PT are owned absolutely by PT;

      5.2.2 the terms of all contracts for the provision of services to PT by


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



<PAGE>

                                        9

            independent contractors contain provisions whereby the contractor is
            subject to strict confidentiality obligations and all discoveries,
            Inventions and Intellectual Property in the Field made by the
            independent contractor in performing the service contracted for are
            owned absolutely by PT;

      5.2.3 PT owns full legal and beneficial title to the PT Rights;

      5.2.4 at the Effective Date PT is not aware of any royalties or other
            payments which are or may become payable to third parties in respect
            of the PT Rights.

 5.3. Each Party warrants and represents that:

      5.3.1 it has all necessary permissions, consents and licences to carry out
            the Project as detailed in the Work Programme;

      5.3.2 it shall ensure that it will be ready and able to undertake the
            Project within 1 (one) month of the date hereof.

 6.   INTELLECTUAL PROPERTY

 6.1. PT shall retain ownership of the PT Rights.

 6.2. PI shall retain ownership of the PI Rights

 6.3. Should any new biological targets outside the Field be generated as a
      result of the Project, PI shall be the owner of all rights pertaining to
      such targets. PT shall have a 90-day right of proposal and negotiation to
      propose a research and development project for such target, such
      negotiation period to occur immediately after the date PT is notified that
      the target has been identified. If PT and PI have not entered into a
      written agreement for such proposed project at the end of such 90-day
      period, then PT shall have no further rights in respect of such target,
      and PI shall proceed as it sees fit; provided, however, that for the
      180-day period following such 90-day period, PI shall not enter into an
      agreement in respect of such target on terms less favourable to PI than
      those last offered to PI by PT during such 90-day period.

 6.4. Each Party hereby grants to the other Party a non-exclusive, royalty-free
      licence (or sub-licence where appropriate and with the approval of the
      head licensee if required) for so long as this Agreement remains in force
      and has not been terminated (but not thereafter) to use such of the PT or
      PI Rights or sub-licence rights in the Field to the MIT Agreement as are
      necessary for the sole purpose of carrying out the Project.

 6.5. All Project Rights shall be jointly owned by PT and PI (except as
      otherwise
<PAGE>

                                       10

      specifically provided for in this agreement) and the Parties shall not
      disclose the same and shall procure that the Inventors under their
      respective control do not disclose the same to any third party except with
      the other Party's prior written consent. Each Party shall (and shall
      procure that those of its employees and others under its control engaged
      on the Project shall if requested) transfer or assign such Project Rights
      to the other Party.

 6.6  All Intellectual Property and Know How resulting from the Project outside
      of the Field shall be owned as follows:

      6.6.1 Any new biological targets (other than Cathepsin S) shall be owned
            by PI;

      6.6.2 Any Invention or improvements relating to RAPiD and compound
            libraries shall be owned by PT;

      6.6.3 Any other Intellectual Property shall be jointly owned. Each Party
            hereby grants to the other a perpetual, royalty-free, worldwide
            licence (with right to sub-license) to use as it sees fit the
            Project Rights that continue to be jointly owned.

 6.7  Each Party shall ensure that the other Party is promptly informed of all
      Inventions arising from the Project or work done on or in connection with
      the Project and shall also ensure that nothing is done by anyone under its
      control to prejudice the grant in the United Kingdom, the United States of
      America or any other part of the world of any patent or other protection
      in respect of any Invention arising from the Project or work done on or in
      connection with the Project.

 6.8  In the event of a person other than an employee of a Party being employed
      on the Project that Party shall before such person is permitted to work on
      the Project obtain the signature of that person to an undertaking covering
      (a) nondisclosure of Confidential Information and (b) the ownership of
      rights in Inventions, Intellectual Property and Know How arising from the
      Project each in terms as if the person were a Party to this Agreement []*

 6.9  In order to facilitate the exploiting of any Invention arising from the
      Project as effectively as possible each Party shall, and shall use all
      reasonable endeavours to procure that the Inventors shall, from time to
      time supply the other Party and its nominees (including licensees) with
      any drawings, models, designs, technical data, computer software,
      information, Know-How, biological material, or plant varieties in their
      possession relating to the Invention.

 6.10 The Parties will file any applications for patents covering jointly-owned
      Project Rights in the joint names of both Parties. The cost of
      prosecution of these patent applications and of maintenance and protection
      of any patents granted,


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

                                       11

      as a result of these applications, shall be shared equally between PT and
      PI. []*

 6.11 For the avoidance of doubt, the Parties anticipate that the
      commercialisation of Cathepsin S inhibitors developed during or in
      connection with the Project will be through the licensing of such
      inhibitors to a major pharmaceutical company. On such a commercialisation
      PT and PI shall each grant the licensee or sub-licensee such licences and
      sub-licences to PT Rights, PI Rights and the MIT Agreement as necessary to
      develop Cathepsin S inhibitors developed during or in connection with the
      Project.

 6.12 All money received by either Party from a third party in respect of
      Project Rights shall first be used to pay for any royalty or other
      payments due to the owners of intellectual property rights licensed by one
      of the Parties and necessary to commercialisation of the Project Rights.
      All money received by either Party from such a third Party shall then be
      used to reimburse each of the Parties, on a pro rata basis, for costs
      incurred in the Project in accordance with Clause 2.7. Thereafter, PT and
      PI shall share equally all Revenue after the payment of any continuing
      royalties or other payments as described in the first sentence of this
      Clause 6.12, which shall be shared equally by the Parties.

 6.13 In the event that a bona fide offer is made to the Parties in relation to
      the commercialisation of Cathepsin S inhibitors developed during or in
      connection with the Project and the Parties cannot agree on whether to
      accept such an offer then the Party which is unwilling to accept the offer
      (the "Refusing Party") shall be obliged to pay the Party which is willing
      to accept the offer (the "Accepting Party") the sum of 50% (fifty percent)
      of the total written and irrevocable offer made by a third party (such an
      offer to be a transaction at arms length) in order to purchase the
      Refusing Party's rights in the Project Rights.

 6.14 Infringement of Patents of Third Parties

      (a) PI shall defend any suit, action or proceeding brought against itself
      or PT alleging the infringement or misappropriation of any patent or any
      other proprietary right of a third party by reason of the use of the PI
      Rights in the Project. PT shall give PI prompt written notice of the
      commencement of any such suit, action or proceeding or any claim of
      infringement against PT and will furnish to PI a copy of each
      communication relating to the alleged infringement and shall give to PI
      all authority (including the right to exclusive control of the defense and
      settlement of any such suit, action or proceeding), information and
      assistance necessary to defend or settle any such suit, action or
      proceeding. PI shall keep PT advised as to, and consult with PT from time
      to time in respect of, all material developments with respect to such
      suit, action or proceeding or any settlement negotiations in connection
      therewith. PI shall pay (i) all expenses (including reasonable attorneys'
      fees) incurred in connection with any such suit,


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

                                       12

      action or proceeding and (ii) any actual damages and costs finally awarded
      against the infringing party as the result of any such suit, action or
      proceeding, or the amount payable in any settlement of any such suit,
      action or proceeding to the extent either arise from the PI Rights. In no
      event shall PI be required to pay to PT any indirect, special, incidental
      or consequential damages of any kind as a result of or in connection with
      any such suit, action or proceeding or the settlement thereof. For
      purposes of this Clause 6.14(a), PI rights shall include any Project
      Rights assigned exclusively to PI.

      (b) PT shall defend any suit, action or proceeding brought against itself
      or PI alleging the infringement or misappropriation of any patent or any
      other proprietary right of a third party by reason of the use of the PT
      Rights in the Project. PI shall give PT prompt written notice of the
      commencement of any such suit, action or proceeding or any claim of
      infringement against PI and will furnish to PT a copy of each
      communication relating to the alleged infringement and shall give to PT
      all authority (including the right to exclusive control of the defense and
      settlement of any such suit, action or proceeding), information and
      assistance necessary to defend or settle any such suit, action or
      proceeding. PT shall keep PI advised as to, and consult with PI from time
      to time in respect of, all material developments with respect to such
      suit, action or proceeding or any settlement negotiations in connection
      therewith. PT shall pay (i) all expenses (including reasonable attorney's
      fees) incurred in connection with any such suit, action or proceeding and
      (ii) any actual damages and costs finally awarded against the infringing
      party as the result of any such suit, action or proceeding, or the amount
      payable in any settlement of any such suit, action or proceeding to the
      extent either arise from the PT Rights. In no event shall PT be required
      to pay to PI any indirect, special, incidental or consequential damages as
      a result of or in connection with any such suit, action or proceeding or
      the settlement thereof. For purposes of this Clause 6.14(b), PT rights
      shall include any Project Rights assigned exclusively to PT.

      (c) Unless otherwise agreed by the parties, PI and PT shall jointly defend
      any suit, action or proceeding brought against either or both of PI or PT,
      alleging the infringement or misappropriation of any patent or any other
      proprietary right of a third party by reason of the use of the
      jointly-owned Project Rights in the Project. If such suit, action or
      proceeding or any claim of infringement is brought against either PI or PT
      (the "Named Party"), such Named Party shall give the other party prompt
      written notice of the commencement of any such suit, action or proceeding
      or any claim of infringement and will furnish the other party with a copy
      of each communication relating to the alleged infringement and shall share
      equally all authority (including the control of the defense and settlement
      of any such suit, action or proceeding), information and assistance
      necessary to defend or settle any such suit, action or proceeding. The
      Named Party shall keep the other party advised as to and consult in
      respect of all developments with respect to such suit, action or
      proceeding or any settlement negotiations in connection
<PAGE>

                                       13

      therewith. The parties shall share equally (i) all expenses (including
      reasonable attorney's fees) incurred in connection with any such suit,
      action or proceeding and (ii) any actual damages and costs finally awarded
      against the infringing party as the result of any such suit, action or
      proceeding, or the amount payable in any settlement of any such suit,
      action or proceeding to the extent either arise from the Project Rights.
      In no event shall either party be required to pay the other any indirect,
      special, incidental or consequential damages as a result of or in
      connection with any such suit, action or proceeding or the settlement
      thereof.

 7.   CONFIDENTIALITY

 7.1. For the purposes of this Clause, "Confidential Information" means all
      information of a confidential nature disclosed (whether in writing,
      verbally or any other means and whether directly or indirectly) by one
      Party ("the Disclosing Party") to the other Party ("the Receiving Party")
      whether before or after the Effective Date including, without limitation,
      any information relating to the Disclosing Party's products, operations,
      processes, plans or intentions, product information, Know How,
      Intellectual Property, Inventions, trade secrets, market opportunities and
      business affairs.

 7.2. Subject always to Clause 7.5 during the term of this Agreement and after
      termination or expiration of this Agreement for any reason whatsoever the
      Receiving Party shall:

      7.2.1 keep the Confidential Information confidential; and

      7.2.2 not disclose the Confidential Information to any other person other
            than with the prior written consent of the Disclosing Party or in
            accordance with Clause 7.5; and

      7.2.3 not use the Confidential Information for any purpose other than the
            performance of its obligations or the exercise of its rights under
            this Agreement.

 7.3. During the term of this Agreement the Receiving Party may disclose the
      Confidential Information to its employees, sub-contractors or agents or
      others engaged on the Project and to potential licensees in terms of
      Clause 6.10 (the "Recipient") to the extent that it is necessary for the
      purposes of effectively carrying on the Project or commercialising
      Cathepsin S inhibitors developed during the Project.

 7.4. The Receiving Party shall procure that each Recipient is made aware of and
      complies with all the Receiving Party's obligations of confidentiality
      under this Agreement and shall obtain the signature of the Recipient to an
      undertaking covering (a) non-disclosure of confidential information and
      (b) the ownership of


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.




<PAGE>

                                       14

      rights in Inventions, Intellectual Property and Know How arising from the
      Project each in terms as if the Recipient were a Party to this Agreement
      []*

 7.5. The obligations contained in Clauses 7.2 and 7.4 shall not apply to any
      Confidential Information which:

      7.5.1 is at the Effective Date or at any time after the Effective Date
            comes into the public domain other than through breach of this
            Agreement by the Receiving Party or any Recipient; or

      7.5.2 can be shown by the written records of the Receiving Party to have
            been known by the Receiving Party before disclosure by the
            Disclosing Party to the Receiving Party; or

      7.5.3 subsequently comes lawfully into the possession of the Receiving
            Party from a third Party under no obligation of confidence to the
            Disclosing Party in respect of such Confidential Information.

 7.6. Each Party shall use reasonable endeavours to ensure that no disclosure or
      publication or dissemination of work done on or in connection with the
      Project takes place in any manner (whether orally or in writing or
      otherwise) without the prior written consent of the other Party except as
      specified in Clauses 7.3 and 7.4.

 8.   ANNOUNCEMENTS

      No public announcement, communication or circular (other than to the
      extent required by law, The London Stock Exchange Limited or the Panel on
      Takeovers and Mergers or any other regulatory body in any jurisdiction or
      by PT or PI for the purpose of raising funds) concerning the transactions
      referred to in this Agreement shall be made or despatched for so long as
      this Agreement continues in force by either Party without the prior
      written consent of the other Party (such consent not to be unreasonably
      withheld or delayed). The Parties agree that immediately following the
      execution of this Agreement a press release shall be released concerning
      the completion of this Agreement along with the major commercial terms and
      that similar press releases shall be released throughout the term of the
      project as major milestones are achieved.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>

                                       15

 9.   GENERAL

 9.1. This Agreement constitutes the entire agreement between the Parties
      relating to the subject matter of this Agreement and supersedes all
      previous such agreements whether written, oral or in any other form.

 9.2. No variation of this Agreement shall be valid unless it is in writing and
      signed by or on behalf of each of the Parties.

 9.3. The failure to exercise or delay in exercising a right or remedy under
      this Agreement shall not constitute a waiver of the right or remedy or a
      waiver of any other rights or remedies and no single or partial exercise
      of any right or remedy under this Agreement shall prevent any further
      exercise of the right or remedy or the exercise of any other right or
      remedy.

 9.4. Except as expressly provided in this Agreement the rights and remedies
      contained in this Agreement are cumulative and not exclusive of any rights
      or remedies provided by law.

 9.5. Any date, time or period referred to in this Agreement is of the essence
      except only to the extent to which the Parties agree in writing to vary
      it, in which event the varied date, time or period is of the essence.

 9.6. Nothing in this Agreement shall be construed as creating a partnership
      between the Parties or as constituting either Party as the agent of the
      other Party for any purpose whatsoever and neither Party shall have the
      authority or power to bind the other Party or to contract in the name of
      or create a liability against the other Party in any way or for any
      purpose.

 9.7. Neither Party shall assign or transfer or purport to assign or transfer
      any of its rights or obligations under this Agreement except with the
      prior written consent of the other Party provided however that either
      Party may assign any of its rights or obligations under this Agreement to
      any Affiliate, if the assigning Party guarantees the performance of such
      Affiliate of the assigned obligations under this Agreement, or to any
      company with which it may merge or consolidate or to which it may sell all
      or substantially all of its assets, without obtaining the consent of the
      other Party.

 9.8. Any notice or other communication under or in connection with this
      Agreement shall be in writing and shall be delivered personally or sent by
      first class post pre-paid recorded delivery (and air mail if overseas) or
      by fax, to the Party due to receive the notice or communication at its
      address set out in this Agreement or such other address as either Party
      may specify by notice in writing to the other.
<PAGE>

                                       16

 9.9  This Agreement is governed by, and shall be construed in accordance with,
      English law. The courts of England shall have exclusive jurisdiction to
      hear and determine any suit, action or proceedings, and to settle any
      disputes, which may arise out of or in connection with this Agreement
      (respectively, "Proceedings" and "Disputes") and, for such purpose, each
      of the Parties hereby irrevocably submit to the jurisdiction of the courts
      of England.

 9.10 Each Party irrevocably waives any objection which it might at any time
      have to the courts of England being nominated as the forum to hear and
      determine any Proceedings and to settle any Disputes and agrees not to
      claim that the courts of England are not a convenient or appropriate
      forum.

 9.11 Each Party shall use its reasonable endeavours to carry out the tasks
      allocated to it in Schedule 1 hereto. If a Party uses reasonable
      endeavours to accomplish the tasks allocated to it, such Party's failure
      to accomplish those tasks shall not be deemed to be a breach of this
      Agreement.

 9.12 Except for claims arising from the breach of Clauses 7 and 2.9 and the
      non-competition provisions of Clauses 4.4 and 4.5 of this Agreement, in no
      event shall either party be required to pay the other party any indirect,
      special, incidental or consequential damages of any kind as a result of or
      in connection with any suit, action or proceeding, brought by a party to
      this Agreement or a third party, or the settlement thereof.
<PAGE>

                                       17

IN WITNESS WHEREOF this Agreement has been executed by the Parties on the date
which first appears in this Agreement.

FOR PEPTIDE THERAPEUTICS LIMITED:


/s/ N A Higgins          Signature of Director
- ------------------------

    N. A. Higgins        Name of Director
- ------------------------

FOR PEPTIMMUNE INC.:


/s/ Ben R. Bronstein     Signature of Officer
- ------------------------

    Ben R. Bronstein     Name of Officer
- ------------------------

    President            Officer Title
- ------------------------
<PAGE>

                                       18

                                   SCHEDULE 1

                                 Work Programme

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



<PAGE>

                                       19

SCHEDULE 2

                                    Accounts

[]*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



<PAGE>


                                                                    EXHIBIT 10.4


                  COLLABORATIVE RESEARCH AND OPTION AGREEMENT

This COLLABORATIVE RESEARCH AND OPTION AGREEMENT is entered into as of
December 22, 1997 by and between PFIZER INC., a Delaware corporation, having an
office at 235 East 42nd Street, New York, New York 10017 and its Affiliates
("Pfizer"), and PEPTIDE THERAPEUTICS LIMITED ("Peptide"), a corporation having
an office at 321 Cambridge Science Park, Milton Road, Cambridge CB4 4WG,
England.

WHEREAS, Peptide has developed a vaccine candidate for the prevention and/or
treatment of allergy; and

WHEREAS, Peptide has already granted an exclusive world-wide license for human
applications of the vaccine to SmithKline Beecham plc; and

WHEREAS, Peptide wishes to grant an exclusive world-wide license for
veterinary applications of the vaccine to Pfizer; and

WHEREAS, Pfizer has the capability to undertake research for the discovery and
evaluation of agents for prevention and/or treatment of allergy and also the
capability for clinical analysis, manufacturing and marketing with respect to
such agents;

NOW, THEREFORE, the parties agree as follows:

1.    Definitions

Whenever used in this Agreement, the terms defined in this Section 1 shall have
the meanings specified.

1.1     "Allergy Vaccine" means the vaccine comprising a certain peptide
        sequence from the target animal species from the fourth constant region
        of IgE coupled to a carrier. Examples of peptide sequences include but
        are not limited to; 

        []*

        []*

        []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>

1.2     "Affiliate" means any corporation or other legal entity owning, directly
        or indirectly, fifty percent (50%) or more of the voting capital shares
        or similar voting securities of Pfizer or Peptide; any corporation or
        other legal entity fifty percent (50%) or more of the voting capital
        shares or similar voting rights of which is owned, directly or
        indirectly, by Pfizer or Peptide or any by a corporation or other legal
        entity which owns, directly or indirectly, fifty percent (50%) or more
        of the voting capital shares of similar voting rights of which is owned,
        directly or indirectly, by a corporation or other legal entity which
        owns, directly or indirectly, fifty percent (50%) or more of the voting
        capital shares or similar voting securities of Pfizer or Peptide.

1.3     "Research Plan" means the written plan describing the research and
        budgets for the research to be carried out by Pfizer pursuant to this
        Agreement, as may be amended from time to time. The current Research
        Plan is attached to and made a part of this Agreement as Exhibit A.

1.4     "Research Program" is the research program in the Area conducted by
        Pfizer pursuant to the Research Plan in effect during the Contract
        Period.

1.5     "Effective Date" is December 22, 1997.

1.6     "Contract Period" means the period beginning on the Effective Date and
        ending on the date on which this Agreement terminates.

1.7     "Area" means veterinary applications of the Allergy Vaccine which shall,
        for the avoidance of doubt, exclude any and all applications to humans
        of the Peptide Technology.

1.8     "Technology" means and includes all materials, technology, technical
        information, know-how, expertise and trade secrets within the Area.

1.9     "Peptide Patents" means (i) the patents and patent applications set out
        in Exhibit B including all continuations, continuations-in-part,
        divisions, and renewals, all letters patent granted thereon, and all
        reissues, re-examinations and extensions thereof and (ii) any
        corresponding patent applications in additional countries and (iii) any
        patents and


<PAGE>

        patent applications owned or controlled solely by Peptide which Peptide
        is free to offer to Pfizer and covering improvements and/or other
        developments of the patents and patent applications mentioned in (i) and
        (ii) hereinbefore

1.10    "Peptide Technology" means Technology that Peptide has the lawful right
        to disclose or otherwise transfer use rights to Pfizer and that is or
        was:

        (a)    developed by employees of or consultants to Peptide alone or
               jointly with third parties prior to the Effective Date; or

        (b)    acquired by purchase, license, assignment or other means from
               third parties by Peptide prior to the Effective Date.

        (c)    for the avoidance of doubt Peptide Technology shall include
               "Peptide Patents set forth in parts (i) and (ii) of section 1.9".

1.11    "Joint Technology" means Technology that is or was:

        (a)    developed by employees of or consultants to Pfizer using Peptide
               Technology during the Contract Period;

        (b)    developed by employees of or consultants to Peptide alone or
               jointly with third parties in the Area during the Contract
               Period, except for Technology so developed that Peptide is
               prohibited to disclose or otherwise transfer use rights to Pfizer
               by the terms of an agreement in existence at such time as the
               subject matter thereof became a part of the Research Plan; or

        (c)    acquired by purchase, license, assignment or other means from
               third parties by Peptide in the Area during the Contract Period,
               except for Technology so acquired that Peptide is prohibited to
               disclose or otherwise transfer use rights to Pfizer by the terms
               of an agreement in existence at such time as the subject matter
               thereof became a part of the Research Plan.

1.12    "Pfizer Technology" means Technology that Pfizer has the lawful right to
        disclose or otherwise transfer use rights to Peptide and that is or was:


<PAGE>

        (a)    developed by employees of or consultants to Pfizer alone or
               jointly with third parties prior to the Effective Date or during
               the Contract Period.

        (b)    acquired by purchase, license, assignment or to other means from
               third parties by Pfizer prior to the Effective Date or during the
               Contract Period.

1.13    "Peptide Confidential Information" means all information about any
        element of the Peptide or Joint Technology which is disclosed by Peptide
        to Pfizer and designated "Confidential" in writing by Peptide at the
        time of disclosure to Pfizer to the extent that such information as of
        the date of disclosure to Pfizer is not (i) known to Pfizer other than
        by virtue of a prior confidential disclosure to Pfizer by Peptide; or
        (ii) disclosed in published literature, or otherwise generally known to
        the public through no fault or omission of Pfizer; or (iii) obtained
        from a third party free from any obligation of confidentiality to
        Peptide.

1.14    "Pfizer Confidential Information" means all information about any
        element of Pfizer or Joint Technology which is disclosed by Pfizer to
        Peptide and designated "Confidential" in writing by Pfizer at the time
        of disclosure to Peptide to the extent that such information as of the
        date of disclosure to Peptide is not (i) known to Peptide other than by
        virtue of a prior confidential disclosure to Peptide by Pfizer; or (ii)
        disclosed in published literature, or otherwise generally known to the
        public through no fault or omission of Peptide; or (iii) obtained from a
        third party free from any obligation of confidentiality to Pfizer.

1.15    "Joint Patent Rights" means all patentable inventions within Joint
        Technology including all the valid claims of patent applications,
        whether domestic or foreign, claiming such patentable inventions,
        including all continuations, continuations-in-part, divisions, and
        renewals, all letters patent granted thereon, and all reissues,
        re-examinations and extensions thereof.

1.16    "Product" means the Allergy Vaccine or any product for the prevention
        and/or treatment of allergy in animals, the manufacture, use, sale,
        offer for sale or import of which would infringe a valid claim within
        Peptide Patents or Joint Patent Rights in the absence of a license.

<PAGE>

2.      Research Program

2.1     Purpose. Pfizer shall conduct the Research Program throughout the
        Contract Period. All Technology in the Area developed in the Research
        Program will become part of the Joint Technology. The objective of the
        Research Program is to develop prophylactic and/or therapeutic vaccines
        against allergy for animals, based on the Allergy Vaccine.

2.2     Research Plan. The Research Plan is described in the attached Exhibit A.
        The attached Research Plan, and any subsequent Research Plan, shall be
        amended from time to time, as needed, and made part of this Agreement.

2.3     Exclusivity. Peptide agrees that during the Contract Period, and in the
        Area, neither Peptide nor any of its Affiliates shall sponsor any other
        research, or engage in any research sponsored by any third party without
        Pfizer's consent.

2.4     Reports and Materials

2.4.1   Reports.  During the Contract Period, Pfizer shall furnish to Peptide:

        (a)    brief summary written reports within ten (10) business days after
               the end of each three-month period commencing on the Effective
               Date, describing its progress under the Research Plan; and

        (b)    comprehensive written reports within forty-five (45) days after
               the end of the twelve (12) month period commencing on the
               Effective Date, describing in detail the work accomplished by it
               under the Research Plan and discussing and evaluating the results
               of such work.

2.4.2   Materials. Peptide shall, during the Contract Period, as a matter of
        course as described in the Research Plan, or upon Pfizer's written or
        oral request, furnish to Pfizer samples of Allergy Vaccine and other
        reagents in reasonable quantities which are necessary for Pfizer to
        carry out its responsibilities under the Research Plan.


<PAGE>

2.5     Laboratory Facilities and Personnel. Pfizer shall provide suitable
        laboratory facilities, equipment and personnel for the work to be done
        by Pfizer in carrying out the Research Program. Peptide shall provide
        technical assistance to Pfizer in carrying out the Research Plan as may
        be requested and/or required by Pfizer during the Contract Period. Such
        technical assistance may include visits by Peptide personnel to Pfizer
        facilities. In the event Pfizer requests that Peptide personnel visit
        Pfizer facilities, Pfizer shall reimburse Peptide for reasonable costs
        associated with such visit, including lodging and travel expenses.

2.6     Diligent Efforts. Pfizer shall use reasonably diligent efforts to
        achieve the objectives of the Research Program. Pfizer shall carry out
        the Research Program using qualified personnel in accordance with
        generally accepted professional standards for such work; however, it is
        recognised by both parties that the work is developmental or
        experimental in nature and there can be no guarantee of success or that
        any particular result can be obtained in a timely fashion.

3.      Funding the Research Program

3.1     Research Funding. Pfizer shall perform the research in accordance with
        the Research Plan at no cost to Peptide, except as otherwise provided in
        this Agreement.

4.      Treatment of Confidential Information

4.1     Confidentiality

4.1.1   Pfizer and Peptide each recognise that the other's Confidential 
        Information constitutes highly valuable, confidential information. 
        Subject to, the obligations set forth in sections 4.2 and 4.3, Pfizer 
        and Peptide each agree that during the term of this Agreement and for 
        seven (7) years thereafter, it will keep confidential, and will cause 
        its Affiliates to keep confidential, all Peptide Confidential 
        Information or Pfizer Confidential Information, as the case may be, 
        that is disclosed to it, or to any of its Affiliates pursuant to this 
        Agreement.  Neither Pfizer nor Peptide nor any of their respective 
        Affiliates shall use such Confidential Information except as 
        expressly permitted in this Agreement.


<PAGE>

4.1.2   Pfizer and Peptide each agree that any disclosure of the other's
        Confidential Information to any officer, employee or agent of the
        other party or of any of its Affiliates shall be made only if and to
        the extent necessary to carry out its responsibilities under this
        Agreement and shall be limited to the maximum extent possible
        consistent with such responsibilities.  Pfizer and Peptide  each agree
        not to disclose the other's Confidential Information to any third
        parties under any circumstance without written permission from the
        other party.  Each party shall take such action, and shall cause its
        Affiliates to take such action, to preserve the confidentiality of
        each other's Confidential Information as it would customarily take to
        preserve the confidentiality of its own Confidential Information.
        Each party, upon the other's request, will return all the Confidential
        Information disclosed to the other party pursuant to this Agreement,
        including all copies and extracts of documents, within sixty (60) days
        of the request upon the termination of this Agreement except for one
        (1) copy which may be kept for the purpose of complying with
        continuing obligations under this Agreement.

4.1.3   Pfizer represents that all of its employees, and any consultants to
        Pfizer, participating in the Research Program who shall have access to
        Peptide Technology or Joint Technology and Peptide Confidential
        Information are bound by agreement to maintain such information in
        confidence.

4.2     Publication. Notwithstanding any matter set forth with particularity in
        this Agreement to the contrary, results obtained in the course of the
        Research Program may be submitted for publication following scientific
        review by the Peptide and Pfizer management. After receipt of the
        proposed publication by both Pfizer and Peptide management's written
        approval or disapproval shall be provided by Pfizer and Peptide within
        sixty (60) days or time otherwise sufficient to allow for filing for
        patent protection on the contents of the publication. In the event of
        disagreement concerning approval or disapproval, Pfizer shall have final
        decision making authority.

4.3     Publicity. Except as required by law, or the rules of any stock
        exchange, neither party may disclose the terms of this Agreement nor the
        research described in it without the written consent of the other party,
        which consent shall not be unreasonably withheld. However, Pfizer
        acknowledges that Peptide wishes to announce the signing of this
        Agreement without disclosing any commercial terms and shall provide a
        draft press


<PAGE>

        release for Pfizer's approval prior to such announcement which shall not
        be unreasonably withheld or delayed.

4.4     Disclosure of Inventions. Pfizer shall promptly inform Peptide about all
        inventions in the Area that are conceived, made or developed in the
        course of carrying out the Research Program by employees of, or
        consultants to, Pfizer.

4.5     Restrictions on Transferring Materials. Pfizer and Peptide recognise
        that the biological, synthetic chemical and biochemical materials which
        are part of Pfizer Technology, Peptide Technology or Joint Technology,
        represent valuable commercial assets. Therefore, throughout the Contract
        Period and for seven (7) years thereafter, subject to the license rights
        granted in Section 5.3, Peptide and Pfizer agree not to transfer such
        materials of the other party or joint materials to any third party,
        unless prior written consent for any such transfer is obtained from the
        other party.

5.      Intellectual Property Rights. The following provisions (section 6, 7 and
        8) relate to rights in the intellectual property developed or used by
        Pfizer during the course of carrying out the Research Program.

6.      Ownership. All Peptide Confidential Information and Peptide Technology
        shall be owned by Peptide. All Pfizer Confidential Information and
        Pfizer Technology shall be owned by Pfizer. All Joint Technology shall
        be owned jointly by Peptide and Pfizer. All Joint Patent Rights shall be
        jointly owned.

7.      Grant of Research Licenses. Peptide grants to Pfizer a nonexclusive,
        irrevocable, world-wide, royalty-free license, including the right to
        grant sub-licenses to Affiliates, to make and use Peptide Confidential
        Information and Peptide Technology and Joint Technology and Joint Patent
        Rights for all research purposes other than the sale or manufacture for
        sale of products or processes.

8.      Grant of License Option.  As consideration for Pfizer's performance of
        the Research Program and the payment by Pfizer to Peptide on the date
        of signing this Agreement of the total sum of []* during the term of 
        this Agreement and for a period of six (6) months thereafter, Pfizer 
        shall have the exclusive option to acquire an exclusive world-wide, 
        royalty bearing, license,



- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>

        including the right to grant sub-licenses, to make, use, sell, offer for
        sale and import Products under all Peptide's right, title and interest
        in the Peptide Technology, Joint Technology and Joint Patent Rights in
        every country in the world. If Pfizer wishes to take up the option then
        the parties shall negotiate in good faith to reach agreement on the
        terms of the license which shall include the terms set forth in Exhibit
        C.

9.      Term and Termination

9.1     Term. Unless sooner terminated or extended, this Agreement shall expire
        []*

9.2     Events of Termination. The following events shall constitute events of
        termination ("Events of Termination"):

        (a)    any written representation or warranty by Peptide or Pfizer, or
               any of its officers, made under or in connection with this
               Agreement shall prove to have been incorrect in any material
               respect when made, or

        (b)    Peptide or Pfizer shall fail in any material respect to perform
               or observe any term, covenant or understanding contained in this
               Agreement or in any of the other documents or instruments
               delivered pursuant to, or concurrently with this Agreement, and
               any such failure shall remain unremedied for ninety (90) days
               after written notice to the failing party.

9.3     Termination

9.3.1   Upon the occurrence of any Event of Termination, the party not
        responsible may, by notice to the other party, terminate this Agreement.

9.3.2   Pfizer may terminate this Agreement, with or without cause, upon ninety
        (90) days notice to Peptide.

9.3.3   If Pfizer terminates this Agreement pursuant to Section 9.2(a) or
        9.2(b), the license option set forth in Section 8 shall continue
        according to its terms. If Peptide terminates


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

        this Agreement pursuant to Section 9.2(a) or 9.2(b), that license shall,
        only upon mutual agreement of the parties, continue according to its
        terms.

9.3.4   Termination of this Agreement for any reason shall be without prejudice
        to any other remedies which either party may otherwise have.

9.3.5   If Pfizer do not exercise the License Option as described in section 8
        then Pfizer shall;

            (i)   grant to Peptide a royalty free perpetual license with a right
                  of sub-license for research purposes to use the Joint
                  Technology within the Area

            (ii)  grant to Peptide a royalty bearing perpetual license with a
                  right of sub-license for commercial purposes to use the Joint
                  Technology within the Area. The commercial terms for such a
                  license to be reasonable taking into account the relative
                  contribution of the Joint Technology and the Peptide
                  Technology

10.     Representations and Warranties. Peptide and Pfizer each represent and
        warrant as follows:

10.1    It is a corporation duly organised validly existing and is in good
        standing and is qualified to do business and is in good standing as a
        foreign corporation in each jurisdiction in which the conduct of its
        business or the ownership of its properties requires such qualification
        and has all requisite power and authority, corporate or otherwise, to
        conduct its business as now being conducted, to own, lease and operate
        its properties and to execute, deliver and perform this Agreement.

        The execution, delivery and performance by it of this Agreement have
        been duly authorised by all necessary corporate action and do not and
        will not (a) require any consent or approval of its stockholders, (b)
        violate any provision of any law, rule, regulations, order, writ,
        judgement, injunctions, decree, determination award presently in effect
        having applicability to it or any provision of its certificate of
        incorporation or by-laws or (c) result in a breach of or constitute a
        default under any material agreement, mortgage, lease, license, permit
        or other instrument or obligation to which it is a party or by which it
        or its properties may be bound or affected.


<PAGE>

10.2    This Agreement is a legal, valid and binding obligation of it
        enforceable against it in accordance with its terms and conditions,
        except as such enforceability may be limited by applicable bankruptcy,
        insolvency, moratorium, reorganisation or similar laws, from time to
        time in effect, affecting creditor's rights generally.

10.3    It is not under any obligation to any person, or entity, contractual or
        otherwise, that is conflicting or inconsistent in any respect with the
        terms of this Agreement or that would impede the diligent and complete
        fulfilment of its obligations.

10.4    It has good and marketable title to or valid leases or licenses for, all
        of its properties, rights and assets necessary for the fulfilment of its
        responsibilities under the Research Program, subject to no claim of any
        third party other than the relevant lessors, licensors or lienors.

11.     Covenants of Peptide and Pfizer other than Reporting Requirements.
        Throughout the Contract Period, Peptide and Pfizer each shall:

11.1    maintain and preserve its corporate existence, rights, franchises and
        privileges in the jurisdiction of its incorporation, and qualify and
        remain qualified as a foreign corporation in good standing in each
        jurisdiction in which such qualification is from time to time necessary
        or desirable in view of their business and operations or the ownership
        of their properties.

11.2    comply in all material respects with the requirements of all applicable
        laws, rules, regulations and orders of any government authority to the
        extent necessary to conduct the Research Program, except for those laws,
        rules, regulations, and orders it may be contesting in good faith.

12.     Indemnification.  Pfizer will []*



- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>




[   ]*


13.     Notices. All notices shall be in writing mailed via certified mail,
        return receipt requested, courier, or facsimile transmission addressed
        as follow, or to such other address as may be designated from time to
        time:

        If to Pfizer:   To Pfizer at its address as set forth at the beginning
                        of this Agreement.
                        Attention: Vice President, Animal Health Discovery
                        Research with copy to: Legal Division, Groton, CT 06345.

        If to Peptide:  Peptide at its address as set forth at the beginning of
                        this Agreement.
                        Attention: Commercial Director.

        Notices shall be deemed given as of the date received.

14.     Governing Law. This Agreement shall be governed by and construed in
        accordance with the laws of England.

15.     Miscellaneous

15.1    Binding Effect. This Agreement shall be binding upon and inure to the
        benefit of the parties and their respective legal representatives,
        successors and permitted assigns.

15.2    Headings. Paragraph headings are inserted for convenience of reference
        only and do not form a part of this Agreement.

15.3    Counterparts. This Agreement may be executed simultaneously in two or
        more counterparts, each of which shall be deemed an original.

15.4    Amendment, Waiver. This Agreement may be amended, modified, superseded
        or cancelled, and any of the terms may be waived, only by a written
        instrument executed by each party or, in the case of waiver, by the
        party or parties waiving compliance. The


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

        delay or failure of any party at any time or times to required
        performance of any provisions shall in no manner affect the rights at a
        later time to enforce the same. No waiver by any party of any condition
        or of the breach of any term contained in this Agreement, whether by
        conduct, or otherwise, in any one or more instances, shall be deemed to
        be, or considered as, a further or continuing waiver of any such
        condition or of the reach of such term or any other term of this
        Agreement.

15.5    No Third Party Beneficiaries. No third party including any employee of
        any party to this Agreement, shall have or acquire any rights by reason
        of this Agreement. Nothing contained in this Agreement shall have or
        acquire any rights by reason of this Agreement. Nothing contained in
        this Agreement shall be deemed to constitute the parties partners with
        each other or any third party.

15.6    Assignment and Successors. This Agreement may not be assigned by either
        party, except that each party may assign this Agreement and the rights
        and interests of such party, in whole or in part, to any of its
        Affiliates, any purchaser of all or substantially all of its assets or
        to any successor corporation resulting from any merger or consolidation
        of such party with or into such corporations.

15.7    Force Majeure. Neither Pfizer nor Peptide shall be liable for failure of
        or delay in performing obligations set forth in this Agreement, and
        neither shall be deemed in breach of its obligations, if such failure or
        delay is due to natural disasters or any causes reasonably beyond the
        control of Pfizer or Peptide.

15.8    Severability. If any provision of this Agreement is or becomes invalid
        or is ruled invalid by any court of competent jurisdiction or is deemed
        unenforceable, it is the intention of the parties that the remainder of
        the Agreement shall not be affected.


<PAGE>



IN WITNESS WHEREOF, the parties have caused this Agreement to be executed by
their duly authorised representatives.

                              PFIZER INC


                              By: /s/ illegible
                                 -----------------------------------

                              Title: President, Central Reasearch
                                    --------------------------------
                                     Vice President, Pfizer Inc.

                              PEPTIDE THERAPEUTICS LIMITED


                              By: /s/ NA Higgins
                                 -----------------------------------

                              Title: Commercial Director
                                    --------------------------------



<PAGE>


                                    EXHIBIT A

                                Anti-IgE Vaccine

          Development Plan for Decapeptide from Peptide Therapeutics

         []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>


                                    EXHIBIT B

                                   The Patents


         []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>


                                    EXHIBIT C


         []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>


                                                                    EXHIBIT 10.5


                                  CONFIDENTIAL


                            R&D AND LICENSE AGREEMENT


     This License Agreement ("Agreement") is made effective as of the seventh
(7th) day of February 1997 ("Effective Date"), between PEPTIDE THERAPEUTICS
LIMITED, having a place of business at 321 Cambridge Science Park, Milton Road,
Cambridge CB4 4WG, United Kingdom (herein referred to as "PTL") and SMITHKLINE
BEECHAM PLC, having a place of business at New Horizons Court, Great West Road,
Brentford, Middlesex TW8 9EP, United Kingdom (herein referred to as "SB").


                                 WITNESSETH THAT:


     WHEREAS, PTL is the owner of and/or controls all right, title and interest
in certain patents, identified in Schedule A hereto, and know-how relating to
anti IgE vaccine(s); and

     WHEREAS, PTL has developed and/or controls certain technologies relating to
prevention, control and/or treatment of allergic disorders in humans which may
be useful for the development of active or passive prophylactic or therapeutic
anti IgE vaccine(s) against allergies.

     WHEREAS, PTL and SB have an interest to enter into a research collaboration
for the development and commercialisation of the above mentioned vaccines.

     WHEREAS, SB has an interest in acquiring simultaneously a worldwide and
exclusive license under any existing and future patent, patent applications,
know how and improvements owned, controlled or developed by PTL relating to the
above mentioned technologies.


                                       1

<PAGE>

     NOW, THEREFORE, in consideration of the covenants and obligations expressed
herein and intending to be legally bound, and otherwise to be bound by proper
and reasonable conduct, the parties agree as follows :


1.   DEFINITIONS

     1.01   "AFFILIATE(S)" shall mean any corporation, firm, partnership or
            other entity, whether de jure or de facto, which directly or
            indirectly owns, is owned by or is under common ownership with a
            party to this Agreement to the extent of at least fifty percent (50
            %) of the equity (or such lesser percentage which is the maximum
            allowed to be owned by a foreign corporation in a particular
            jurisdiction) having the power to vote on or direct the affairs of
            the entity and any person, firm, partnership, corporation or other
            entity actually controlled by, controlling or under common control
            with a party to this Agreement.

     1.02   "COMBINATION" shall mean a PRODUCT which contains also one or more
            therapeutically and/or prophylactically active antigens and/or
            allergens which are not included in TECHNOLOGY. Any COMBINATION is a
            PRODUCT.

     1.03   "FIELD" shall mean prevention, control and/or treatment of any and
            all allergic disorders in humans, (including but not limited to Type
            1 hypersensitivity (allergy) reactions) mediated by IgE immune
            activity and/or other immune mechanisms, excluding SPECIFIC FIELD.

     1.04   "KNOW-HOW" shall mean all present and future technical information,
            materials and know-how which relate to PRODUCT which are now and/or
            at anytime during the term of this Agreement developed, owned,
            proprietary to and/or controlled by PTL and/or any AFFILIATES of
            PTL, and which are necessary for or useful to the development,
            production and commercialisation of PRODUCT. KNOW-HOW shall include,
            without limitation, all chemical, pharmacological, toxicological,
            clinical, assay, control and manufacturing data and any other
            information relating thereto and any materials, seeds, strains,
            reagents and media. KNOW-HOW shall not include PATENTS.

     1.05   "NET SALES VALUE" shall mean the gross receipts from sales of
            PRODUCT in the TERRITORY by SB and/or its AFFILIATES and/or its
            sublicensees and/or its distributors to THIRD PARTIES less the
            following deductions :

                                       2
<PAGE>

            (i)    []* of the gross receipts to cover transportation charges, 
                  including insurance; and

            (ii)  SB's standard costs for PRODUCT formulation, filling and
                  packaging, for syringes and other administration devices
                  combined with, or contained in, commercial packaging; and

            (iii) sales and excise taxes and duties paid or allowed by a selling
                  party and any other governmental charges imposed upon the
                  production, importation, use or sale of PRODUCT, including
                  without limitation, contributions and payments required by any
                  governmental authorities as liability provisions and/or made
                  pursuant to injury compensation schemes and/or as PRODUCT
                  liability insurance premiums; and

            (iv)  trade, quantity and cash discounts, commissions and other
                  customary rebates; and

            (v)   allowances or credits to customers or charges back from
                  customers on account of rejection or return of PRODUCT subject
                  to royalty under this Agreement or on account of retroactive
                  price reductions affecting such PRODUCT; and

            (vi)  royalties payable and/or paid by SB to THIRD PARTIES on the
                  manufacture, use and/or sale of PRODUCT []* .

            Sales between or among SB and its AFFILIATES or sublicensees or
            distributors shall be excluded from the computation of NET SALES
            VALUE except where such AFFILIATES or sublicensees are end users,
            but NET SALES VALUE shall include the subsequent final sales to
            THIRD PARTIES by such AFFILIATES or sublicensees or distributors.

            If a PRODUCT is sold as a COMBINATION, NET SALES VALUE of
            COMBINATION shall be multiplied by the fraction A/A+B where A is the
            unit invoice price of a separately sold PRODUCT which contains as
            specific immunogenic material only those antigen(s) and/or
            allergen(s) contained in COMBINATION which are included in
            TECHNOLOGY and B is the unit invoice price of a separately sold
            vaccine which contains as specific immunogenic 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       3
<PAGE>

            material only those antigen(s) and/or allergen(s) contained in
            COMBINATION but which are not included in TECHNOLOGY.

            If the unit invoice price of (i) a separately sold PRODUCT which
            contains the antigen(s) and/or allergen(s) which are included in
            TECHNOLOGY and/or (ii) a separately sold vaccine which contains
            antigen(s) and/or allergen(s) contained in COMBINATION but which are
            not included in TECHNOLOGY, is not available and the parties are
            unable to agree on an alternative arrangement, the parties shall
            agree within 60 days of a request from one of the parties the
            appointment of an independent expert ("the Expert") to determine the
            relative value of the vaccines described in (i) and (ii) of this
            paragraph ("the Vaccine Values"). The Expert shall act as expert and
            not as arbitrator and the Expert fee shall be split equally between
            the parties. The Expert shall be instructed to take into account a
            statement of facts relating to vaccines described in (i) and (ii) as
            are agreed by the parties and all relevant market circumstances in
            determining the Vaccine Values. The Expert will present to both
            parties in writing the determined Vaccine Values together with a
            statement justifying the underlying calculations and assumptions.
            The decision of the Expert shall be final and binding on the
            parties.


            If the parties are unable to agree within sixty (60) days the
            appointment of an Expert, the following formula shall apply: NET
            SALES VALUE of COMBINATION shall be multiplied by a fraction X/Y
            wherein X is the number of antigen(s) and/or allergen(s) contained
            in PRODUCT which are included in TECHNOLOGY and Y is the total
            number of antigens and/or allergens included in COMBINATION.

     1.06   "OTHER KNOW-HOW" shall mean technical information, materials and
            know-how, excluding OTHER PATENTS, which are owned and/or controlled
            by THIRD PARTIES and which are or may become necessary or useful for
            the development, production and/or commercialisation of PRODUCT.

     1.07   "OTHER PATENTS" shall mean patents and/or patent applications owned
            and/or controlled by THIRD PARTIES having claims which would be
            infringed by SB making, having made, using, having used, selling or
            having sold PRODUCT.

     1.08   "PATENTS" shall mean all patents and patent applications which are
            or become owned and/or controlled, in whole or in part, by PTL
            and/or any AFFILIATES of PTL and under which PTL has, now or in the
            future, the right to grant licenses and which generically or
            specifically claim PRODUCT and/or use of PRODUCT 

                                       4
<PAGE>

            and/or a process for manufacturing PRODUCT, and/or intermediates
            used in such process. Included within the definition of PATENTS are
            any continuations, continuations-in-part, divisions, patents of
            addition, reissues, renewals or extensions (other than SPC) thereof.
            Also included within the definition of PATENTS but subject to
            Section 2.08 are any patents or patent applications which
            generically or specifically claim or have claims covering any
            improvements of PRODUCT or intermediates or manufacturing processes
            required or useful for production of PRODUCT which are developed by
            PTL, and/or under which PTL otherwise has the right to grant
            licenses or sublicenses, now or in the future, during the term of
            this Agreement. The current list of patent applications and patents
            encompassed within PATENTS is set forth in Schedule A attached
            hereto.

     1.09   "PRODUCT" shall mean any and all therapeutic and/or prophylactic
            vaccine(s) for use in the FIELD in any formulation, configuration,
            combination and/or delivery system, which is included in TECHNOLOGY.

     1.10   "PTG' shall mean Peptide Therapeutics Group plc a company
            incorporated in England and Wales (Registered number 2863682) which
            registered office is at 321 Cambridge Science Park, Milton Road,
            Cambridge, CB4 4WG, United Kingdom.

     1.11   "PTL" shall mean Peptide Therapeutics Limited.

     1.12   "SB" shall mean SmithKline Beecham plc

     1.13   "SPC" shall mean all Supplementary Protection Certificates for
            medicinal products and their equivalents provided under the Council
            Regulation (EEC) No 1768/92 of June 18, 1992.

     1.14   "SPECIFIC FIELD" shall mean prevention, control and/or treatment of
            allergic disorders in humans using []* .

     1.15   "TECHNOLOGY" shall mean KNOW HOW and/or PATENTS.

     1.16   "TERRITORY" shall mean all the countries and territories in the
            world.

     1.17   "THIRD PARTY(IES)" shall mean any party which is neither a party to
            this Agreement nor an AFFILIATE.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       5
<PAGE>

     For the purpose of this Agreement, except as otherwise expressely provided
     in this Agreement or unless the context otherwise requires : (a) defined
     terms include the plural as well as the singular and the use of any gender
     shall be deemed to include the other gender; (b) references to "Articles",
     "Sections" and other subdivisions and to "Schedules" and "Exhibits" without
     reference to a document, are to designated Articles, Sections and other
     subdivisions of, and to Schedules and Exhibits to, this Agreement; (c) the
     use of the term "including" means "including but not limited to"; and (d)
     the words "herein", "hereof", "hereunder" and other words of similar import
     refer to this Agreement as a whole and not to any particular provisions.


2.   RESEARCH COLLABORATION

     2.01.  Subject to Sections 2.02 and 2.03 hereunder, the parties shall
            undertake a two (2) year collaborative research program starting
            from the Effective Date (hereinafter "Research Program") dedicated
            to the demonstration of technical feasibility and development of
            PRODUCT by PTL aimed at inter alia:

             []* 

            as further outlined in Schedule B attached hereto.

            PTL agrees to make available resources in the amount of []* per 
            year to support the performance of the Research Program and shall 
            dedicate at least []* annual funding (`Dedication') to the
            accomplishment of steps (i), (ii) and (iii) as specified above in
            this Section 2.01. At SB's request, PTL will provide written
            evidence of such Dedication (`Evidence').


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       6
<PAGE>



     2.02   Schedule B shall be supplemented within twelve (12) months of the
            Effective Date by an additional Schedule (`Schedule D') which will
            form part of this Agreement and which shall detail a specific
            experimental strategy designed to achieve the broader objectives
            outlined in Schedule B.

            In Schedule D, SB shall as appropriate revise the objectives and
            plans outlined in Schedule B and shall set certain scientific
            milestones. In the event such milestones are not achieved as
            determined by SB, PTL shall at SB's request, allocate greater or
            fewer resources under the Research Program or the Extended Research
            Program (as defined in Section 2.03) as the case may be, to any
            scientific or developmental objectives including if appropriate
            steps (i) to (iv) above identified by SB within the limits stated in
            Section 2.01.

     2.03   At SB's sole discretion, the Research Program shall be extended by
            quarterly periods for []* starting on the second anniversary of the 
            Effective Date ("Extended Research Program"). To support the 
            performance of the Extended Research Program SB and PTL shall each 
            pay []* with period of extension with the same provisions regarding 
            Dedication and Evidence as detailed above in Section 2.01 or as 
            modified pursuant to Section 2.02, second paragraph.

     2.04   Any further extension and appropriate funding of the Research
            Program beyond the Extended Research Program will be subject to
            prior written agreement between both parties.

     2.05   SB shall have an unconditional and irrevocable option which it may
            exercise through written notification to PTL within thirty (30) days
            of the expiration of the Research Program or the Extended Research
            Program, as the case may be , to discontinue the collaboration with
            PTL in the FIELD. In such case, the provisions of Sections 4.02 and
            12.03 shall apply.

     2.06   SB will conduct all activities related to toxicological and clinical
            developments of PRODUCT and such activities shall be under SB's sole
            control and expense. PTL shall however use its reasonable endeavours
            to seek additional public sector grant funding for such 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       7
<PAGE>

            activities, such funding to be wholly contributed to the Research
            Program or Extended Research Program to the extent allowed by the
            grant-giving body.

     2.07   During the Research Program and the Extended Research Program if
            any, either party shall submit to the other party quarterly progress
            reports detailing the research and development work accomplished in
            the previous quarter.

     2.08   Any invention or discovery in the FIELD made solely by PTL during
            the course of the Research Program and Extended Research Program if
            any, shall be owned solely by PTL. Any invention or discovery in the
            FIELD made solely by SB during the course of the Research Program
            and Extended Research Program if any, shall be owned solely by SB.
            Any invention or discovery in the FIELD made jointly by PTL and SB
            during the course of the Research Program and Extended Research
            Program if any, shall be jointly owned by SB and PTL.

     2.09   Any patent and/or patent application arising out of an invention or
            discovery in the FIELD made solely by an employee or agent of SB
            shall be filed in the name of SB. Any patents and/or patent
            application arising out of an invention or discovery in the FIELD
            made solely by an employee or agent of PTL shall be filed in the
            name of PTL and such PATENTS shall be automatically and exclusively
            licensed to SB by PTL hereunder. Any patents and/or patent
            applications arising out of an invention or discovery in the FIELD
            made jointly by SB and PTL shall be filed in the joint names of SB
            and PTL, provided that (i) claims covering epitopes from, or
            mimetopes of, the constant region of IgE, whether or not coupled to
            a carrier shall fall under PATENTS and such PATENTS shall be
            automatically and exclusively licensed to SB by PTL hereunder and
            (ii) PTL will grant to SB an irrevocable, exclusive, fully paid-up,
            royalty free license under PTL's rights to any subject matter other
            than mentioned in (i) above contained in such jointly made invention
            or discovery.

                                       8
<PAGE>


3.   GRANT

     3.01   PTL hereby grants to SB and to any AFFILIATES of SB an exclusive
            license, with the right to grant sublicenses, under TECHNOLOGY and
            any SPC to make, have made, use, have used, sell, offer for sale,
            have sold, keep and/or import in the TERRITORY all subject matter
            encompassed within TECHNOLOGY including any and all PRODUCTS,
            subject to the terms and conditions of this Agreement.


4.   PAYMENTS AND ROYALTIES

     4.01   SB shall make the following non refundable payment to PTL : two
            million four hundred thousand pounds sterling (L2,400,000)
            upon the Effective Date as consideration for the license and rights
            granted hereunder.

            In addition SB shall grant to PTL an interest free loan of []* for 
            a duration of up to six (6) months. PTL shall at the expiration of 
            this loan sell SB []* unencumbered ordinary shares of PTG at a 
            price of three pounds and sixty pence (L3.60) per share and SB shall
            purchase these []* unencumbered ordinary shares of PTG at a price 
            of three pounds and sixty pence (L3.60) per share according to 
            the terms of a Subscription Agreement attached hereto as Schedule 
            C. As also provided for in Schedule C, PTL agrees to undertake 
            its best efforts to obtain the necessary approvals of PTG 
            including PTG's shareholder approval to make available these 
            shares.

            In addition SB shall purchase to a value of []* unencumbered 
            ordinary shares of PTG at a price of three pounds and sixty pence 
            (L3.60) per share, under the Subscription Agreement attached hereto 
            as Schedule C, such shares to be tradeable only according to the 
            provisions of the Subscription Agreement.

     4.02   If SB has not exercised its option after the expiration of the 
            Research Program or the Extended Research Program, as the case 
            may be, pursuant to Section 2.05 above, SB shall immediately pay 
            PTL a lump sum (`Licence Maintenance Fee') of []* and this 
            Agreement shall 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       9
<PAGE>

            continue in full force and effect. []*

            []*

            []*

     4.03   SB shall pay once only the following amounts to PTL upon achievement
            of the following Milestones:


            []*




- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       10
<PAGE>


            []*



            For the avoidance of doubt, the maximum Milestones payable, 
            assuming all Milestones have been achieved, shall be []* .

            In Section 4.03 the following terms shall have the meanings defined
            below:

            []* 



- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       11

<PAGE>

            []*

            For the avoidance of doubt, if any Submission or Approval covers
            more than one of the indications defined above then the Milestone
            payments for all the indications covered by such Submission or
            Approval shall be payable.

            All Submission and Approval Milestones are fully creditable against
            current and future royalties provided that such credits shall not
            cause the royalties payable in any one calendar year to be reduced
            by more than fifty percent (50 %). However any unused credit will be
            carried forward to any following calendar year.

     4.04   As consideration for the license under PATENTS granted to SB under
            this Agreement and subject to Sections 4.06 and 5, SB shall pay the
            following royalties ("Patent Royalty") :

            []*

            from sales of PRODUCT in countries in which PTL has a granted,
            unencumbered, unrevoked PATENT covering such PRODUCT.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       12

<PAGE>

            Patent Royalty obligations hereunder in each country of the
            TERRITORY shall expire upon the expiration, lapse or invalidation of
            the last remaining PATENT covering PRODUCT in such country or
            fifteen (15) years from the date of first bona fide commercial sale
            of PRODUCT in such country, whichever comes first.

     4.05   As consideration for the license to KNOW-HOW granted to SB under
            this Agreement and subject to Section 5, SB shall pay to PTL for a
            period of ten (10) years from the first bona fide commercial sale of
            PRODUCT anywhere in the TERRITORY the following royalties ("Know-How
            Royalty") :

            []* 

            from sales of PRODUCT in countries where PTL has no granted,
            unencumbered, unrevoked PATENT covering such PRODUCT.provided that
            the making, using or selling of PRODUCT actually uses KNOW-HOW which
            is both secret and substantial and has been identified as such by
            PTL in writing.

     4.06   SB's royalty obligations under Section 4.04 shall become effective
            in each country in the TERRITORY at such time as anunrevoked and
            unencumbered PATENT covering PRODUCT is granted in such country. In
            the event that any person or party initiates any legal proceeding or
            proceeding at a competent patent office challenging the validity,
            scope or enforceability of a PATENT in any country in the TERRITORY,
            then the Patent Royalty payable on NET SALES VALUE in such country
            shall, during pendency of the proceeding, be paid into a separate
            account (`Escrow Account') of SB from which no amounts can be
            withdrawn during such pendency without the prior consent of PTL. The
            Escrow 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       13
<PAGE>

            Account shall be at a UK bank and the number and address of
            the account shall be communicated to PTL. If the validity and
            enforceability of claims in the PATENT which cover PRODUCT are
            upheld by a court or other legal tribunal or competent patent office
            from which no appeal is or can be taken, then the amount of Patent
            Royalty paid into the Escrow Account, during the period of
            suspension, less any Know-How Royalty paid under Section 4.05, shall
            be promptly paid to PTL with any interest earned thereon. If the
            claims in the PATENT which cover PRODUCT are held to be invalid or
            otherwise unenforceable by a court or other legal or administrative
            tribunal from which no appeal is or can be taken then the amount of
            Patent Royalty paid into the Escrow Account with any interest earned
            thereon shall be transferred to SB and no further Patent Royalty
            shall be owed. Further, a holding of invalidity or unenforceability
            of any PATENT, from which no further appeal is or can be taken,
            shall not affect any obligation accrued before payment of Patent
            Royalty into the Escrow Account, but shall eliminate royalties
            otherwise due under such PATENT from the date such holding becomes
            final.

     4.07   NET SALES VALUE for the purposes of calculating the Patent Royalty
            or Know-How Royalty under Section 4.04 and 4.05 respectively shall
            be determined separately.


5.  COMPULSORY LICENSES AND THIRD PARTY LICENSES

     5.01   In the event that a governmental agency in any country or territory
            grants or compels PTL, or SB, to grant a license under TECHNOLOGY to
            any THIRD PARTY for products that compete with PRODUCT, SB shall
            have the benefit in such country or territory (and in any other
            country into which products that compete with PRODUCT are sold by
            such THIRD PARTY compulsory licensee) of any terms granted to such
            THIRD PARTY to the extent that such terms are more favourable to the
            THIRD PARTY than those granted to SB under this Agreement.

     5.02   The parties recognize that OTHER PATENTS and/or OTHER KNOW-HOW may
            exist. (i) If at any time during the term of this Agreement, SB, at
            its sole discretion deems it useful or necessary to seek a license
            under OTHER PATENTS and/or OTHER KNOW-HOW from any THIRD PARTIES in
            order to practice the license granted by PTL to SB hereunder and
            avoid infringement during such exercise in a particular country or
            (ii) in the event that royalties

                                       14
<PAGE>

            and/or fees are payable by SB to THIRD PARTIES on sales of PRODUCT
            (which may include, but shall not be limited to, royalties and/or
            fees payable for adjuvants, carriers and/or other technology
            included in PRODUCT) other than pursuant to (i) above,such THIRD
            PARTY royalties and/or fees shall be deducted from royalties
            otherwise due to PTL under Section 4.04 and 4.05 as follows :

            -  []* of royalties and/or fees payable to THIRD PARTIES shall be 
               deducted for such royalties and/or fees as are of an amount less 
               than or equal to []* of that portion of total annual NET SALES 
               VALUE which exceeds []*; and

            -  []* of all other royalties and/or fees payable to THIRD PARTIES 
               shall be deducted.

     5.03   Without prejudice to the provision contained in Section 4.03 last
            paragraph, no deductions from royalties made under Section 5.02
            above may have the effect of reducing royalties otherwise due to PTL
            under Section 4.04 by more than []* in any calendar year nor 
            royalties otherwise due to PTL under Section 4.05 by more
            than []* in any calendar year. However any unused credit will be 
            carried forward to any following calendar year.

     5.04   Nothwithstanding Sections 5.02 and 5.03, in the event that (i) SB
            establishes by means of written evidence provided to PTL, or (ii)
            failing provision of such evidence that the parties agree (such
            agreement not to be unreasonably withheld), or (iii) failing such
            agreement that a court of competent jurisdiction declares, that
            royalties and/or fees are payable by SB to THIRD PARTIES on sales of
            PRODUCT and such royalties and/or fees arise from inclusion of the
            Immunogen or the Immunogenic Conjugate in PRODUCT, such THIRD PARTY
            royalty and/or fee shall be deducted in full from any royalties
            payable by SB to PTL

            In any negotiation with such THIRD PARTY, SB shall use its
            reasonable endeavours to minimise royalties and/or fees payable to
            the THIRD PARTY.

            For the purposes of this Section 5.05, `Immunogen' and `Immunogenic
            Conjugate' shall have the meaning given in the claims of granted
            European Patent EP0477231 and in PCT/GB 95/02580 (= W096/14333) as
            amended by attorney letter of 18th September 1996, respectively.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       15
<PAGE>

            For the avoidance of doubt, "inclusion of Immunogen in PRODUCT" or
            "inclusion of Immunogenic Conjugate in PRODUCT" shall mean that the
            PRODUCT including such Immunogen or Immunogenic Conjugate is
            susceptible of inducing an immune response to the epitope included
            in such Immunogen or Immunogenic Conjugate when presented to the
            immune system, whether in admixture with other materials, as a
            conjugate or otherwise joined to a carrier entity or molecule
            including T-cell epitopes.

            For epitopes other than those included in Immunogenic Conjugate or
            Immunogen and developed during the Research Programme or Extended
            Research Program, the parties shall discuss prior to development of
            any such other epitope whether they expect any THIRD PARTY fees
            and/or royalties to be due. In the event that the parties have
            agreed to proceed with development of such an epitope then such
            THIRD PARTY royalty and/or fees payable shall be fully deducted from
            any royalties payable by SB to PTL provided that one of the
            conditions referred to under (i), (ii) or (iii) in the first
            paragraph of this Section 5.05 has been met and SB has used
            reasonable endeavours to minimise royalties and/or fees payable to
            such THIRD PARTY.

6.   TOLERISING PEPTIDE OPTION

     6.01   "Clinical Study" shall mean []*

            "Clinical Report" shall mean []*

     6.02   PTL hereby grants to SB an exclusive option exerciseable as set out
            in this Section 6 for a period of two (2) years from the Effective
            Date for a worldwide and exclusive license to the TOLERISING PEPTIDE
            as described in []* 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       16
<PAGE>


     []*

     6.03   The option granted in 6.02 shall be exerciseable by SB following
            []*. If a written expression of interest is received by PTL from SB 
            within three (3) months of []* the parties shall negotiate in
            good faith the terms of the licence which will conform to minimum
            terms to be agreed by the parties within three (3) months of the
            Effective Date. If no such written expression of interest is
            received by PTL from SB, PTL will be free to deal in the TOLERISING
            PEPTIDE as it sees fit provided however that PTL shall not offer a
            licence to the TOLERISING PEPTIDE to any THIRD PARTY within []* of 
            the termination of such three (3) month period without first 
            offering such a licence to SB on substantially the same conditions
            as those considered for offer to the THIRD PARTY.

7.   DEVELOPMENT

     7.01   SB will, in accordance with SB's reasonable business and scientific
            judgement, exercise its reasonable efforts and diligence in
            developing and commercialising PRODUCT and in undertaking
            investigations and actions required to obtain appropriate
            governmental approvals to market PRODUCT. All such activity shall be
            undertaken at SB's expense. At SB's request, PTL shall supply to SB
            reasonable technical assistance in undertaking such investigations
            and actions.

     7.02   SB shall report to PTL on the status and progress of SB's efforts to
            develop and commercialise PRODUCT at such times and in such manner
            as PTL may reasonably request.

     7.03   PTL shall supply any KNOW-HOW which SB may require and shall provide
            to SB, at SB's request, technical assistance within its area of
            expertise concerning development, production and commercialisation
            of PRODUCT. Provision of such technical assistance shall include,
            but not be limited to, visits by PTL personnel to SB at PTL's
            expense, and visits by SB personnel to PTL, at SB's expense, at
            times and for periods of time upon which the parties will agree.

     7.04   On completion of the Research Program or the Extended Research
            Program, as the case may be, SB agrees, in furtherance of its
            obligations under Sections 7.01 and 7.02, to dedicate minimum
            resources to developing and 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       17
<PAGE>

            commercialising PRODUCT of []* annually. SB agrees to provide 
            evidence of such dedication on each six (6) monthly anniversary 
            of the Effective Date following the expiration of the Research 
            Program or the Extended Research Program as the case may be. In 
            the event of SB failing to dedicate this annual minimum resources, 
            PTL shall be entitled to serve written notice to SB pursuant to 
            Section 12.04.

8.   EXCHANGE OF INFORMATION AND CONFIDENTIALITY

     8.01   During the term of this Agreement, SB shall have full access to all
            matters encompassed within TECHNOLOGY and PTL shall upon the request
            of SB promptly disclose and/or supply SB with all TECHNOLOGY.

     8.02   During the term of this Agreement, SB shall have full access to (and
            PTL will promptly disclose upon request of SB) all technology,
            information, inventions, data, process technology and any other
            information related to PRODUCTS, whether patentable or not, which
            PTL may develop, acquire or otherwise have or obtain rights or
            access to, and where appropriate the foregoing shall be subject to
            Sections 2.08 and 2.09 above. Either party will at least once a year
            disclose to the other party indicative commercial information
            related to PRODUCT as follows: general review of progress, size of
            target populations, timetable for regulatory approvals and clinical
            trial plans. PTL agrees that this information carries no warranty as
            to its accuracy and SB is not obliged to proceed to any action based
            thereon.

     8.03   During the term of this Agreement, each party shall promptly
            disclose to the other party any information that it obtains or
            develops regarding the utility and safety of PRODUCT and shall
            promptly report to the other party any confirmed information of
            serious or unexpected reactions or side effects related to the
            utilisation or medical administration of PRODUCT.

     8.04   During the term of this Agreement and for five (5) years thereafter,
            irrespective of any termination earlier than the expiration of the
            term of this Agreement, PTL and SB shall not use or reveal or
            disclose to THIRD PARTIES any confidential information received from
            the other party including that referred to in Sections 7.04, 8.02
            and 8.03 or otherwise developed by either party in the performance
            of activities in furtherance of this Agreement without first
            obtaining the written consent of the other party, except as may be
            otherwise provided herein, or as 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       18
<PAGE>

            may be required for purposes of investigating, developing,
            manufacturing or marketing PRODUCT or for securing essential or
            desirable authorisations, privileges or rights from governmental
            agencies, or is required to be disclosed to a governmental agency,
            or is necessary to file or prosecute patent applications concerning
            PRODUCT or to carry out any litigation concerning PRODUCT. This
            confidentiality obligation shall not apply to such information which
            is or becomes a matter of public knowledge, or is already in the
            possession of the receiving party, or is disclosed to the receiving
            party by a THIRD PARTY having the right to do so, or is subsequently
            and independently developed by employees of the receiving party or
            AFFILIATES thereof who had no knowledge of the confidential
            information disclosed. The parties shall take reasonable measures to
            ensure that no unauthorised use or disclosure is made by others to
            whom access to such information is granted.

     8.05   Nothing herein shall be construed as preventing either party from
            disclosing any information received from the other party to an
            AFFILIATE or sublicensee or distributor, provided such AFFILIATE or
            sublicensee or distributor has undertaken a similar obligation of
            confidentiality with respect to the confidential information.

     8.06   All confidential information disclosed by one party to the other
            shall remain the intellectual property of the disclosing party. In
            the event that a court or other legal or administrative tribunal,
            directly or through an appointed master, trustee or receiver,
            assumes partial or complete control over the assets of a party to
            this Agreement based on the insolvency or bankruptcy of such party,
            the bankrupt or insolvent party shall promptly notify the court or
            other tribunal (i) that confidential information received from the
            other party under this Agreement remains the property of the other
            party and (ii) of the confidentiality obligations under this
            Agreement. In addition, the bankrupt or insolvent party shall, to
            the extent permitted by law, take all steps necessary or desirable
            to maintain the confidentiality of the other party's confidential
            information and to insure that the court, other tribunal or
            appointee maintains such information in confidence in accordance
            with the terms of this Agreement.

     8.07   No public announcement or other disclosure to THIRD PARTIES
            concerning the existence of or terms of this Agreement shall be
            made, either directly or indirectly, by any party to this Agreement,
            except as may be legally required or as may be required for
            recording purposes, without first obtaining the approval of the
            other party and agreement upon the nature and text of such

                                       19
<PAGE>

            announcement or disclosure, such agreement not to be unreasonably
            withheld or delayed. For the avoidance of doubt, the parties agree
            that it will be deemed unreasonable for SB to withhold or delay
            agreement relating to announcements about achievement of milestones
            under Section 4.03 and about the current status (phase) of clinical
            trials and it will be deemed reasonable for SB to withhold or delay
            agreement relating to announcements describing details of clinical
            trials including data. The party desiring to make any such public
            announcement or other disclosure shall use reasonable efforts to
            inform the other party of the proposed announcement or disclosure in
            reasonable sufficient time prior to public release, and shall use
            reasonable efforts to provide the other party with a written copy
            thereof, in order to allow such other party to comment upon such
            announcement or disclosure.

     8.08   Neither SB nor PTL shall submit for written or oral publication any
            manuscript, abstract or the like which includes data or other
            information generated and provided by the other party without first
            obtaining the prior written consent of the other party, which
            consent shall not be unreasonably withheld. The contribution of each
            party shall be noted in all publications or presentations by
            acknowledgement or coauthorship, whichever is appropriate.


 9.  PATENT PROSECUTION AND LITIGATION

     9.01   Subject to Section 2.08 and 2.09 above, PTL shall be responsible for
            the filing, prosecution and maintenance of PATENTS at its own
            expense. PTL shall disclose to SB the complete texts of all patents
            and patent applications filed and/or controlled by PTL which relate
            to PRODUCT as well as all information received concerning the
            institution or possible institution of any interference, opposition,
            re-examination, reissue, revocation, nullification or any official
            proceeding involving a PATENT anywhere in the TERRITORY. SB shall
            have the right to review all such pending applications and other
            proceedings and make recommendations to PTL concerning them and
            their conduct and PTL shall take any such SB comment and
            recommendation into consideration. PTL agrees to keep SB promptly
            and fully informed of the course of patent prosecution or other
            proceedings including the provision to SB of copies of substantive
            communications, search reports and THIRD PARTY observations
            submitted to or received from patent offices throughout the
            TERRITORY. PTL shall provide such patent consultation to SB at no
            cost to SB. SB shall hold all 

                                       20
<PAGE>

            information disclosed to it under this section as confidential
            subject to the provisions of Sections 8.04 and 8.05.

     9.02   SB shall have the right but not the obligation to assume
            responsibility for any PATENT or any part of a PATENT which PTL
            desires, after consultation with SB, to abandon or otherwise cause
            or allow to be forfeited.

     9.03   In the event of the institution of any suit by a THIRD PARTY against
            PTL, SB or their AFFILIATES or SB's sublicensees or distributors for
            patent infringement involving the manufacture, use, sale,
            distribution or marketing of PRODUCT anywhere in the TERRITORY, the
            party sued shall promptly notify the other party in writing. SB
            shall have the right but not the obligation to defend such suit at
            its own expense. PTL and SB shall assist one another and cooperate
            in any such litigation at the other's request without expense to the
            requesting party.

     9.04   In the event that PTL or SB becomes aware of actual or threatened
            infringement of a PATENT anywhere in the TERRITORY, that party shall
            promptly notify the other party in writing. Following expiration of
            the Research Program or Extended Research Program, as the case may
            be, SB shall have the first right but not the obligation to bring,
            at its own expense, an infringement action against any THIRD PARTY
            and to use PTL's name in connection therewith. If SB has not
            commenced a particular infringement action within ninety (90) days
            of notification of any such infringement, PTL, after notifying SB in
            writing, shall be entitled to bring such infringement action at its
            own expense. During the Research Program or Extended Research
            Program, as the case may be, SB and PTL shall agree on bringing
            either jointly or solely any infringement action against any THIRD
            PARTY and expenses will be shared equally. The party conducting such
            action shall have full control over its conduct, including
            settlement thereof. In any event, PTL and SB shall assist one
            another and cooperate in any such litigation at the other's request
            without expense to the requesting party.

     9.05   PTL and SB shall recover their respective actual out-of-pocket
            expenses, or equitable proportions thereof, associated with any
            patent litigation or settlement thereof from any recovery made by
            any party. Any excess amount shall be shared between SB and PTL,
            with the party conducting a particular infringement action receiving
            []* and the other party receiving []* of such excess.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       21
<PAGE>

     9.06   The parties shall keep one another informed of the status of and of
            their respective activities regarding any patent litigation or
            settlement thereof concerning PRODUCT.

     9.07   PTL shall authorise SB to act as PTL's agent for the purpose of
            making any application for any extensions of the term of PATENTS and
            shall provide reasonable assistance therefor to SB, at PTL's expense
            (In the United States of America as permitted under Title 35 of the
            United States Code).

     9.08   PTL, on behalf of itself, its officers, agents and successors hereby
            waives any and all actions and causes of action, claims and demands
            whatsoever in law or equity of any kind against SB and its
            AFFILIATES based upon the exercise by SB of its rights under this
            Section 9, except in the case of gross negligence and/or wilful
            misconduct by SB.

     9.09   SB recognises that bringing an infringement action under Section
            9.04 may result in a counterclaim of invalidity of PATENTS and/or
            claims in PATENTS. In defending such counterclaim(s), SB agrees to
            take into reasonable consideration the legitimate rights and
            interests of PTL and/or any licensee(s) of PTL in relation to patent
            claims in the field of animal health contained in PATENTS, bearing
            in mind SB's prime interest in the maintenance of a strong patent
            position covering PRODUCT.


10.  TRADEMARKS

     10.01  SB, at its expense, shall be responsible for the selection,
            registration and maintenance of all trademarks which it employs in
            connection with PRODUCT and shall own and/or control such
            trademarks. Nothing in this Agreement shall be construed as a grant
            of rights, by license or otherwise, to PTL to use such trademarks
            for any purpose.


11.  STATEMENTS AND REMITTANCES

     11.01  SB shall keep and require its AFFILIATES and sublicensees and
            distributors to keep complete and accurate records of all sales of
            PRODUCT under the licenses granted herein. PTL shall have the right,
            at PTL's expense, through a certified public accountant or like
            person reasonably acceptable to SB, to 

                                       22
<PAGE>

            examine the records of SB and its AFFILIATES during regular business
            hours during the life of this Agreement and for six (6) months after
            its termination ; provided, however, that such examination shall not
            take place more often than once a year and shall not cover such
            records for more than the preceding two (2) years and provided
            further that such accountant shall report to PTL only as to the
            accuracy of the royalty statements and payments.

     11.02  Within sixty (60) days after the close of each calendar six (6)
            month period , SB shall deliver to PTL a true accounting of all
            PRODUCTS sold by SB, its AFFILIATES, sublicensees and distributors
            during such semester and shall at the same time pay all royalties
            due. Such accounting shall show sales on a country-by-country and
            product-by-product basis.

     11.03  Any tax paid or required to be withheld by SB on account of
            royalties payable to PTL under this Agreement shall be deducted from
            the amount of royalties otherwise due. SB shall secure and send to
            PTL proof of any such taxes withheld and paid by SB for the benefit
            of PTL.

     11.04  All royalties due under this Agreement shall be payable in pounds
            sterling. If governmental regulations prevent remittances from a
            foreign country with respect to sales made in that country, the
            obligation of SB to pay royalties on sales in that country shall be
            suspended until such remittances are possible. PTL shall have the
            right, upon giving written notice to SB, to receive payment in that
            country in local currency.

     11.05  Monetary conversions from the currency of a foreign country in which
            PRODUCT is sold into British currency shall be made at the exchange
            rate in force on the last business day of the period for which the
            royalties are being paid as published by Banque Generale de
            Belgique, Brussels, Belgium, or on another basis mutually agreed to
            by both parties in writing.


12.  TERM AND TERMINATION

     12.01  Unless otherwise terminated , this Agreement shall expire upon 
            the expiration, lapse or invalidation of the []* after the 
            Effective Date, whichever comes later. Expiration of the 
            Agreement under this Section 12.01 shall not preclude SB from 
            continuing to 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       23
<PAGE>

            exercise the rights and licenses granted to it hereunder without any
            further royalty or other obligation.

     12.02  For the avoidance of doubt, this Agreement may not be terminated by
            either party (except under Sections 12.04 or 12.06) during the
            Research Period or Extended Research Period.

     12.03  This Agreement will terminate if and when SB decides to exercise its
            option pursuant to Section 2.05 to discontinue the collaboration
            with PTL in the FIELD.

     12.04  If either party fails or neglects to perform any material covenants
            or provisions of this Agreement and if such default is not corrected
            within sixty (60) days after receiving written notice from the other
            party with respect to such default, such other party shall have the
            right to terminate this Agreement by giving written notice to the
            party in default provided the notice of termination is given within
            six (6) months of the default and prior to correction of the
            default.

     12.05  At any time after the Research Program or Extended Research Program,
            as the case may be, SB may terminate this Agreement by giving PTL at
            least sixty (60) days written notice thereof.

     12.06  Either party may terminate this Agreement if, at any time, the other
            party shall file in any court or agency pursuant to any statute or
            regulation of (the United States or of) any (individual) state or
            (foreign) country, a petition in bankruptcy or insolvency or for
            reorganisation or for an arrangement or for the appointment of a
            receiver or trustee of the party or of its assets, or if the other
            party proposes a written agreement of composition or extension of
            its debts, or if the other party shall be served with an involuntary
            petition against it, filed in any insolvency proceeding, and such
            petition shall not be dismissed with sixty (60) days after the
            filing thereof, or if the other party shall propose or be a party to
            any dissolution or liquidation, or if the other party shall make an
            assignment for the benefit of creditors.

     12.07  Notwithstanding the bankruptcy of PTL, or the impairment of
            performance by PTL of its obligations under this Agreement as a
            result of bankruptcy or insolvency of PTL, SB shall be entitled to
            retain the licenses granted herein, without any further obligations
            to PTL, subject to PTL's right to terminate this Agreement for
            reasons other than bankruptcy or insolvency as expressly provided in
            this Agreement.

                                       24
<PAGE>

13.  RIGHTS AND DUTIES UPON TERMINATION

     13.01  Upon termination of this Agreement and subject to the provisions
            contained in Section 2, PTL shall have the right to retain any sums
            already paid by SB hereunder, and SB shall pay all sums accrued
            hereunder which are then due.

     13.02  Upon termination of this Agreement under Sections 12.04, 12.05 and
            12.06, SB shall notify PTL of the amount of PRODUCT SB, its
            AFFILIATES and its sublicensees and its distributors then have on
            hand, the sale of which would, but for the termination, be subject
            to royalty, and SB and its AFFILIATES and its sublicensees and its
            distributors shall thereupon be permitted to sell that amount of
            PRODUCT provided that SB shall pay the royalty thereon at the time
            herein provided for.

     13.03  Termination of this Agreement shall terminate all outstanding
            obligations and liabilities between the parties arising from this
            Agreement except those described in Sections 2.08, 2.09, 8.04, 8.05,
            8.07, 8.08, 9.03, 9.06, 9.07, 9.08, 10.01, 11.01, 11.02, 11.03,
            11.04, 11.05, 13.01, 13.02, 13.03, 16.01, 17.01 and 19.01.

     13.04  Upon termination under Sections12.03, 12.04 (but only in the event
            SB is the party in default), 12.05 or 12.06 (but only in the event
            SB is the `other party'), and providing SB or an AFFILIATE of SB has
            ceased to, or does not, conduct activities in the FIELD, or in any
            SPECIFIC FIELD as the case may be, within six (6) months after
            termination, PTL shall have a first right to negotiate with SB a
            license of rights in such FIELD or SPECIFIC FIELD, to any invention
            or discovery owned by SB as are referred to in Sections 2.08 and
            2.09.

     13.05  Without prejudice to Section 2.09 and Section 12.07, in the case of
            termination under Section 12.04 the non-breaching party, or in the
            case of termination under Section 12.06 the `other party', or either
            party in the case of termination otherwise than under Sections 12.04
            and 12.06, shall have the rights to exploit any jointly owned
            know-how and /or patents in the FIELD, without any further
            obligations to the other party, provided that this grant clause
            shall in no event be construed as granting rights to SB to use PTL's
            solely owned TECHNOLOGY, nor to PTL to use any of SB's solely owned
            know-how,inventions, discoveries 

                                       25
<PAGE>

            and/or patents in the FIELD irrespective of whether jointly owned
            patents or know-how relate to the same subject matter, and in the
            event such solely owned patents dominate the jointly owned patents
            in any manner, the party in need of a licence thereto will have to
            seek this licence from the other party independently, and such other
            party shall have no obligation whatsoever to come to an agreement
            with said party in need


     13.06  Nothwithstanding anything to the contrary in this Agreement, the
            parties agree that upon termination of this Agreement for any reason
            whatsoever, other than a termination under Sections 12.04 or 12.06,
            rights to any invention or discovery []* For the avoidance of doubt,
            it is acknowledged and agreed by the parties that both parties will
            be free to exercise the rights assigned to them under this Section
            13.06.


14.  WARRANTIES AND REPRESENTATIONS

     14.01  PTL warrants that it owns or has the right to license the entire
            right, interest and, where appropriate, title in PATENTS and
            KNOW-HOW and has the right to enter into this Agreement.

     14.02  Nothing in this Agreement shall be construed as a warranty that
            PATENTS are valid or enforceable or that their exercise does not
            infringe any patent rights of THIRD PARTIES. PTL hereby represents
            that it has no present knowledge from which it can be inferred that
            PATENTS are invalid or that their exercise would infringe patent
            rights of THIRD PARTIES.

     14.03  PTL acknowledges that, in entering into this Agreement, SB has
            relied or will rely upon information supplied by PTL, information to
            be supplied by PTL, and information which PTL has caused or will
            cause to be supplied to SB by PTL's agents and representatives
            pursuant to that certain Confidentiality Agreement signed by SB s.a.
            on 6th March 1996 and by PTL on March 11, 1996 , (all of such
            information being hereinafter referred to collectively as "Product

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       26
<PAGE>

            Information"). PTL warrants and represents that so far as it is
            aware the Product Information related to PRODUCT and/or TECHNOLOGY
            is and will be timely (depending on the circumstances) and accurate
            and complete in all material respects and that it has undertaken
            such steps as are necessary to ascertain such accuracy and
            completeness. Subject to PTL's compliance with its warranty as to
            accuracy and completeness above, SB accepts it will not contest
            Product Information as supplied. PTL further warrants and represents
            that to the best of its knowledge it has and will supply information
            concerning TECHNOLOGY and PRODUCT which is material to the value of
            the TECHNOLOGY.

     14.04  PTL warrants and represents that its directors, scientists, and
            allergies project team have no present knowledge of the existence of
            any pre-clinical or clinical data or information concerning the
            TECHNOLOGY and PRODUCT which suggests that there may exist toxicity,
            safety and/or efficacy concerns which are likely to materially
            impair the utility and/or safety of the PRODUCT.

     14.05  PTL warrants that the agreement between PTL and British Technology
            Group Limited ("BTG") of 16th June 1994 has been terminated and that
            the intellectual property previously licensed to PTL by BTG under
            this agreement has now been fully assigned to PTL. SB acknowledges
            it has received a copy of the assignment document (appropriately
            redacted to remove any reference to commercial terms) by the
            Effective Date.

     14.06  PTL agrees it will undertake its reasonable efforts to have
            suppliers maintainfor the duration of the Research Program or the
            Extended Research Program, as the case may be, supplies of materials
            to SB for clinical trial purposes and in particular supplies of
            keyhole limpet hemacyanin (`KLH') currently produced by Biosyn GmbH
            and of the decapeptide - KLH conjugate currently produced by Biomira
            Inc. PTL further agrees it will undertake reasonable efforts to have
            such material supplied in a form similar in all respects to material
            used previously in clinical studies carried out by PTL or under
            PTL's control.


15.  FORCE MAJEURE

     15.01  If the performance of any part of this Agreement by either party, or
            of any obligation under this Agreement, is prevented, restricted,
            interfered with or delayed by reason of any cause beyond the
            reasonable control of the party liable to perform, unless conclusive
            evidence to the contrary is provided, the 

                                       27
<PAGE>

            party so affected shall, upon giving written notice to the other
            party, be excused from such performance to the extent of such
            prevention, restriction, interference or delay, provided that the
            affected party shall use its reasonable best efforts to avoid or
            remove such causes of non-performance and shall continue performance
            with the utmost dispatch whenever such causes are removed. When such
            circumstances arise, the parties shall discuss what, if any,
            modification of the terms of this Agreement may be required in order
            to arrive at an equitable solution.


16.  GOVERNING LAW AND JURISDICTION

     16.01  This Agreement shall be deemed to have been made in the United
            Kingdom and its form, execution, validity, construction and effect
            shall be determined in accordance with the laws of England and shall
            be subject to the non-exclusive jurisdiction of the English Courts.


17.  SEPARABILITY

     17.01  In the event any portion of this Agreement shall be held illegal,
            void or ineffective, the remaining portions hereof shall remain in
            full force and effect.

     17.02  If any of the terms or provisions of this Agreement are in conflict
            with any applicable statute or rule of law, then such terms or
            provisions shall be deemed inoperative to the extent that they may
            conflict therewith and shall be deemed to be modified to conform
            with such statute or rule of law.

     17.03  In the event that the terms and conditions of this Agreement are
            materially altered as a result of paragraphs 17.01 or 17.02, the
            parties will renegotiate the terms and conditions of this Agreement
            to resolve any inequities.

18.  ENTIRE AGREEMENT

     18.01  This Agreement, entered into as of the date written above,
            constitutes the entire agreement between the parties relating to the
            subject matter hereof and supersedes all previous writings and
            understandings. No terms or provisions of this Agreement shall be
            varied or modified by any prior or subsequent 

                                       28
<PAGE>

            statement, conduct or act of either of the parties, except that the
            parties may amend this Agreement by written instruments specifically
            referring to and executed in the same manner as this Agreement.


19.  NO WAIVER

     19.01  The failure of either party at any time to exercise any of its
            respective rights under this Agreement shall not be deemed a waiver
            thereof, nor shall such failure in any way prevent either party, as
            the case may be, from subsequently asserting or exercising such
            rights.


20. NOTICES

     20.01  Any notice required or permitted under this Agreement shall be sent
            by certified mail, return receipt requested, postage pre-paid to the
            following addresses of the parties :

                           if to PTL :
                           Peptide Therapeutics Limited
                           Cambridge Science Park,
                           Milton Road, Cambride CB4 4WG
                           United Kingdom
                           Attention : The Company's Secretary
                           Copy to : The Commercial Director

                           If to SB :
                           SmithKline Beecham plc
                           New Horizons Court
                           Great West Road
                           Brentford, Middlesex TW8 9EP
                           United Kingdom

                                       29
<PAGE>



      with copy to :       SmithKline Beecham Biologicals Manufacturing S.A.
                           rue de l'Institut 89
                           1330 Rixensart, Belgium
                           Attention : Senior Vice President, General Manager
                           Additional copy to : Vice President, Director 
                                                Business and Strategy
                                                Development


     20.02  Any notice required or permitted to be given concerning this
            Agreement shall be effective upon receipt by the party to whom it is
            addressed.


21.  ASSIGNMENT AND CHANGE OF CONTROL

     21.01  Neither this Agreement nor any interest hereunder shall be
            assignable or transferable by either party without the written
            consent of the other provided, however, that either party may assign
            this Agreement to any AFFILIATE or to any corporation with which it
            may merge or consolidate or to which it may sell all or
            substantially all of its assets, without obtaining the consent of
            the other party provided the interests of the other party are not
            materially affected.


IN WITNESS WHEREOF, the parties, through their authorised officers, have
executed this Agreement as of the date first written above.


PEPTIDE THERAPEUTICS LIMITED


BY : Illegible

SMITHKLINE BEECHAM PLC


BY : Illegible

                                       30
<PAGE>



List of Schedules

Schedule A : CURRENT PATENTS
Schedule B : R&D Plan
Schedule C : Subscription Agreement
Schedule D : To be provided within twelve months from Effective Date.




                                       31

<PAGE>

                                   Schedule A


[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.





<PAGE>


                                       
                                  SCHEDULE B

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.




<PAGE>


                                                                    EXHIBIT 10.6


                             DATED 30th January 1997


                                 (1) MEDEVA PLC

                            (2) EVANS MEDICAL LIMITED

                        (3) PEPTIDE THERAPEUTICS LIMITED

                       (4) PEPTIDE THERAPEUTICS GROUP PLC


                             ----------------------


                                 SALE AGREEMENT


                             ----------------------


                                  Stringer Saul
                                  Marcol House
                                293 Regent Street
                                 London W1R 7PD


<PAGE>



Date: 30th January 1997


Parties:


(1)      MEDEVA PLC whose registered office is at 10 St James's Street, London
         SW1A 1EF ("Medeva")


(2)      EVANS MEDICAL LIMITED whose registered office is at Evans House, Regent
         Park, Kingston Road, Leatherhead, Surrey KT22 7PQ ("the Vendor")


(3)      PEPTIDE THERAPEUTICS LIMITED whose registered office is at 321
         Cambridge Science Park, Milton Road, Cambridge CB4 4WG ("the
         Purchaser")


(4)      PEPTIDE THERAPEUTICS GROUP PLC whose registered office is at 321
         Cambridge Science Park, Milton Road, Cambridge CB4 4WG ("Peptide")


Recitals:


A        The Vendor carries on, inter alia, research and development into the
         delivery of vaccine antigens at its premises at Imperial College.


B        The Vendor wishes to sell and the Purchaser wishes to purchase the
         rights of the Vendor in technology associated with the delivery of
         certain of such vaccine antigens on the terms and conditions set out
         herein.


C        The Vendor is a wholly-owned subsidiary of Medeva.


D        The Purchaser is a wholly-owned subsidiary of Peptide.


Operative provisions:

1        Interpretation

1.1      In this Agreement including the Schedules:

1.1.1    the following words and expressions have the following meanings, unless
         they are inconsistent with the context:

         "AFFILIATE"                   in respect of any party means any
                                       holding company of that party or a
                                       subsidiary of that party or any company
                                       directly or indirectly in common
                                       ownership with that party to the extent
                                       of more than fifty per cent. (50%) of
                                       its shares or stock having the power to
                                       vote at a general meeting (or
                                       equivalent) being owned by that party or
                                       such holding company and the terms
                                       "holding company" and "subsidiary" shall
                                       have the meaning attributed to them by
                                       the Companies Act
                   
                                       
                                        1
<PAGE>                                 
                                       
                                                                              
                                       1985 as amended by the Companies Act
                                       1989.
                                       
                                                                               
                                                                               
         "ASSETS"                      the assets (or rights in respect of
                                       assets) of the Vendor to be purchased by
                                       the Purchaser as described in clauses
                                       2.1 to 2.4.
                                       
         "COMPLETION"                  completion of the acquisition of the
                                       Assets in accordance with clause 5.
                                       
         "CONSIDERATION"               the consideration for the sale of the
                                       Assets as specified in clause 4.1.
                                       
         []* 

         "DISCLOSURE BUNDLE"           the documents and the information
                                       contained in such documents as are
                                       annexed to the Disclosure Letter or are
                                       referred to or specified in the
                                       Disclosure Letter or such documents.
                                       
         "DISCLOSURE LETTER"           the disclosure letter of today's
                                       date from the Vendor to the Purchaser
                                       with reference to clause 18 and Schedule
                                       2.
                                       
         "DOSSIERS"                    any material within the possession of
                                       the Vendor (and not subject to any
                                       obligation of confidentiality to any
                                       third party) which is included within
                                       the Vendor's United States IND
                                       application in respect of CVD 908.
                                       
                                                                               
         "DUE DATE"                    the first anniversary of the Effective
                                       Date.
                                       
          []* 
                                       
         "DISCLOSURES"                 the disclosures set out in the
                                       Disclosure Letter and the Disclosure
                                       Bundle.
                                       
         "EFFECTIVE DATE"              the close of business on the date
                                       of Completion.
                                       
         "EXCLUDED ASSETS"             all assets of the Vendor other
                                       than those specifically identified
                                       herein as the Assets.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       2
<PAGE>
                                       
          []*

          []*
                                       
         "IMPERIAL COLLEGE"            Imperial College of Science Technology
                                       and Medicine at Exhibition Road London
                                       SW7
                                       
         "[]* PROJECT"                 the []* project which relates to
                                       the development of technology falling
                                       within the scope of patents []*
                                       
         "INTELLECTUAL PROPERTY        any and all interest whether
          RIGHTS"                      legal or beneficial arising under the
                                       laws of England or elsewhere in letters
                                       patent, copyright, design right, rights
                                       in confidentiality, trade mark rights
                                       and any other analogous rights,
                                       applications for any of the foregoing
                                       (and the right to make such
                                       applications).
                                       
         "KNOW-HOW"                    the technical information of the Vendor
                                       to be assigned or licensed hereunder to
                                       the Purchaser which know-how is
                                       necessary to enable the Purchaser to
                                       enjoy the benefits conferred upon it
                                       under this Agreement in respect of the
                                       `A' `B' `C' and `D' Patents, and where
                                       such Know-How is described as `A', `B'
                                       `C' or `D' Patent Know-How it is all
                                       such Know-How which relates to the `A'
                                       `B' `C' or `D' Patents respectively.
                                       
         "LEASEHOLD PROPERTY"          the leasehold premises owned and
                                       occupied by the Vendor at Imperial
                                       College.
                                       
         "LEASE"                       the lease or underlease under which the
                                       Leasehold Property is held.
                                       
          []* 
                                       
         "PATENTS"                     the `A' Patents the `B' Patents the `C'
                                       Patents and the `D' Patents collectively
                                       and in respect of `A', `B', `C' and `D'
                                       Patents referred to

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       3
<PAGE>

                                       below any other patents claiming
                                       priority from the patents so listed or
                                       which are in respect of the same
                                       invention as the patents so listed
                                       including any continuation, continuation
                                       in part or divisional patents or
                                       applications.
                                       
         "`A' PATENTS"                 the patents and patent applications as
                                       listed in Part A of Schedule 1
                                       
         "`B' PATENTS"                 the patents and patent applications
                                       listed in Part B of Schedule1.
                                       
         "`C' PATENTS"                 the patents and patent applications
                                       listed in Part C of Schedule 1.
                                       
         "`D' PATENTS"                 the patents listed in Part D of Schedule
                                       1
                                       
         "`D' FIELD"                   the use of protein carriers for antigens
                                       for mucosal delivery other than in
                                       respect of []* infections.
                                       
         "PROJECT MEETINGS"            those meetings as described in clause
                                       6.11
                                       
         "REGULATIONS"                 the Transfer of Undertakings (Protection
                                       of Employment) Regulations 1981.
                                       
         "STOCKS"                      samples of all strains and recombinant
                                       DNA constructs necessary for the use of
                                       the technology within the VR Field being
                                       the property of the Vendor or its
                                       Affiliates and being in the Vendor's
                                       possession (save in particular for those
                                       materials and consumables related to the
                                       Hepatitis Field).
                                       
         "STOCK EXCHANGE"              The International Stock Exchange of the
                                       United Kingdom and the Republic of
                                       Ireland Limited.
- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       4
<PAGE>
 
                                      
         "VR FIELD"                    the technology within the scope
                                       of the `A' Patents, the Human Vaccine
                                       Field, the `D' Field and any
                                       improvements thereto or developments
                                       thereof, but excluding in every case the
                                       Hepatitis Field
                                       
         "VR PROJECTS"                 the following development projects:
                                       mucosal vaccines for the prevention or
                                       treatment of []*
                                       
         "WARRANTIES"                  the warranties and representations of
                                       the Vendor contained in this Agreement
                                       including those set out in Schedule 2 of
                                       this Agreement.
                                       
         "WARRANTY CLAIM"              any claim by the Purchaser against the
                                       Vendor for breach of any of the
                                       Warranties.
                                       
         []*

1.1.2    all references to a statutory provision or enactment shall be construed
         as including references to:

1.1.2.1  any statutory modification, consolidation or re-enactment (whether
         before or after today's date) for the time being in force;

1.1.2.2  all regulations or orders made pursuant to it;

1.1.2.3  any statutory provision of which it is a consolidation, re-enactment or
         modification;

1.1.3    except where the context otherwise requires, words denoting the
         singular include the plural and vice versa; words denoting any gender
         include all genders; words denoting persons include firms and
         corporations and vice versa;

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       5
<PAGE>

1.1.4    unless otherwise stated, a reference to a clause, sub-clause or
         Schedule is a reference to a clause or a sub-clause of, or a Schedule
         to, this Agreement;

1.1.5    clause headings are for ease of reference only and do not affect the
         construction of this Agreement.

1.1.6    Where clauses or paragraphs in this Agreement or the Schedules contain
         the expression "....to the best of the knowledge and belief of...." or
         "....so far as....is/are aware...." or phrases having a similar meaning
         or effect, they shall be deemed to be followed by the words "....having
         made all due and careful enquiries of officers and employees of the
         Vendor and its Affiliates and without making enquiry of any third
         party(ies)...." in every case.

2        Agreement for Sale

2.1      Subject to the terms and conditions of this Agreement, and in
         particular clause 2.2 below:

2.1.1    the Vendor hereby assigns to the Purchaser the `A' Patents and the `A'
         Patent Know-How;

2.1.2    the Vendor hereby grants to the Purchaser an exclusive world wide
         royalty free sub-licence within the []* (terminable only as 
         provided in clauses 2.8 to 2.12) of the Vendor's rights under
         the `B' Patents and the `B' Patent Know-How in so far as is necessary
         to enable the Purchaser to enjoy the benefits conferred upon it in
         respect of the `B' Patents, subject to any restrictions and
         reservations thereon contained in the []* Agreement and the
         []* Agreement;

2.1.3    the Vendor hereby grants to the Purchaser a non-exclusive world wide
         royalty free sub-licence within the []* (terminable only as 
         provided in clauses 2.8 to 2.12) of the Vendor's rights under
         the `C' Patents to the extent necessary to enable the Purchaser to
         exercise the inventions the subject-matter of the `A', `B', or `D'
         Patents or the New Applications without infringing the `C' Patents and
         the `C' Patent Know-How in so far as is necessary to enable the
         Purchaser to enjoy the benefits conferred upon it in respect of the `C'
         Patents, subject to any restrictions and reservations thereon contained
         in the []* Agreement and the []* Agreement;

2.1.4    the Vendor hereby grants to the Purchaser a non-exclusive world wide
         royalty free licence within the `D' Field (terminable only as provided
         in clauses 2.8 to 2.12) of the Vendor's rights under the `D' Patents to
         the extent only that such licence is necessary to enable the Purchaser
         to work within the `D' Field without infringing the `D' Patents and the
         `D' Patent Know-How insofar as is necessary to enable the Purchaser to
         enjoy the benefits conferred upon it in respect of the `D' Patents,
         subject to any restrictions and reservations therein contained in the
         []* Agreement and the []* Agreement.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       6
<PAGE>

2.2      The assignments licences and sub-licences pursuant to clause 2.1 above
         shall be subject in each and every case to the grant by the Purchaser
         to the Vendor of, and the Purchaser hereby grants to the Vendor, an
         exclusive world wide irrevocable royalty-free licence (including the
         right to sub-license) for all purposes in the []* Field.

2.3      The Vendor shall transfer to the Purchaser the Stocks.

2.4      The Vendor shall within sixty (60) days of the Effective Date supply
         the Dossiers to the Purchaser.

2.5      The Purchaser shall acquire no rights of whatsoever nature to the
         Excluded Assets.

2.6      Where title to any of the Assets lies with an Affiliate of the Vendor
         the Vendor covenants to procure the transfer and assignment of title to
         such Assets in accordance with the terms of this Agreement. In respect
         of any such Assets the Vendor shall be responsible for payment of such
         proportion of the consideration payable hereunder in respect of those
         Assets to its relevant Affiliates and no additional consideration shall
         be payable by the Purchaser in respect thereof to such Affiliate.


2.7      The licences and/or sub-licences hereby granted to the Purchaser in
         respect of the Patents and the Know-How shall remain in full force and
         effect subject to clauses 2.8 to 2.12 until the expiration of the
         relevant `B', `C' or `D' Patent in question.


2.8      The Vendor may terminate any or all licences or sub-licences granted
         under this Agreement in respect of the Patents and/or the Know-How by
         notice in writing to the Purchaser if the Purchaser or any sub-licensee
         of the Purchaser is in material breach of the terms of this Agreement
         including without limitation upon exploitation of any `B' Patent or `C'
         Patent or of any `B' Patent Know-How or `C' Patent Know-How outside the
         []* or in contravention of any restrictions or reservations thereon 
         contained in the []* Agreement or the []* Agreement by the Purchaser
         or at the Purchaser's behest, or any exploitation of any `D' Patent 
         outside the `D' Field, or any exploitation of any Patent or any of 
         the Know-How within the []* Field by the Purchaser or at the 
         Purchaser's behest provided that the Vendor has notified the Purchaser
         of its objection to such breach and the Purchaser has not remedied 
         such breach within 45 days of such notice.


2.9      The Vendor may terminate all licences or sub-licences granted under
         this Agreement in respect of the Patents or Know-How forthwith upon
         notice if the Purchaser shall become insolvent or if a receiver,
         administrator, manager or similar officer shall be appointed in respect
         of the whole or substantial part of its assets or if any order shall be
         made or a resolution passed for winding-up the Purchaser (other than a
         resolution for a members' voluntary winding-up of the Purchaser for the
         purpose of a bona fide amalgamation or reconstruction).


2.10     Any or all licences or sub-licences granted under this Agreement in
         respect of the Patents and/or the Know-How shall determine expire or be
         revoked upon

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       7
<PAGE>


         the termination expiry or revocation of any licence or sub-licence
         pursuant to which the Vendor has granted rights to the Purchaser
         hereunder.


2.11     If the Purchaser shall have failed for any reason whatsoever to pay any
         amount due and payable and not the subject of any bona fide dispute
         under and in accordance with the terms of this Agreement this Agreement
         and any and all licences or sub-licences granted hereunder shall upon 7
         days written notice by the Vendor terminate forthwith unless otherwise
         agreed by the parties.


2.12     The Purchaser shall not itself act nor omit to act, nor procure nor
         allow any other person to act nor omit to act, in any way prejudicial
         to the Patents or the grant of patents the subject of applications
         comprised in the Patents or any licences held by the Vendor or its
         Affiliates under the Patents, and without limiting or restricting the
         Purchaser's legal rights to challenge any patent, the Vendor may
         terminate any of the licences or sub-licences granted hereunder to the
         Purchaser should the Purchaser act in contravention of this clause
         2.12.


3        Tangible know how


3.1      The parties agree and recognise that only a portion of the Know-How to
         be assigned or licensed hereunder has been reduced to tangible form.
         Such tangible `A', `B', `C' and `D' Patent Know-How shall be
         transferred to the Purchaser within a period of two years and in
         accordance with a schedule to be agreed by the parties. The Know-How
         that can be and has not at the date of this Agreement been reduced to
         tangible form, shall be reduced to a tangible form as soon as is
         reasonably practicable and transferred to the Purchaser in accordance
         with a Schedule as the Purchaser may reasonably request and which the
         Vendor shall use its reasonable endeavours to agree provided always
         that the Vendor shall subject to clauses 5.5 and 21 be entitled to use
         and retain duplicate copies of all Know-How.


3.2      The duplicate copies of all Know-How retained by the Vendor under the
         provisions of clause 5.5 shall be held securely by the Vendor and the
         Vendor shall take all reasonable precautions to keep the `A' Patent
         Know-How and the `B' Patent Know-How confidential for a period of five
         (5) years from the date hereof.


3.3      The Vendor's obligations under this clause 3 shall be deemed part of
         and shall be subject always to the limitations on the Vendor's
         obligations contained in clause 3 of the secondment agreement of
         today's date entered between the Vendor and the Purchaser ("the
         Secondment Agreement"), and shall otherwise be conducted in accordance
         therewith.

4        Payments

4.1        The Consideration for the sale by the Vendor of the Assets shall be
           one million pounds sterling ((L)1,000,000) which shall be paid by
           the Purchaser in sterling in cash in one lump sum upon Completion.

                                       8
<PAGE>

4.2      The Funding Contribution as referred to in clause 13 shall be one
         million pounds sterling ((L)1,000,000) which shall be paid by the
         Purchaser in two equal annual instalments, each of which instalments
         shall be five hundred thousand pounds ((L)500,000) payable in
         sterling in cash with the first instalment payable in one lump sum upon
         Completion and the second instalment payable in one lump sum upon the
         Due Date.

4.3      The IP Management Fee as referred to in clause 11 shall be []* which 
         shall be paid by the Purchaser in two equal annual instalments, each 
         of which instalments shall be []* payable in sterling in cash with 
         the first instalment payable in one lump sum upon Completion and the 
         second instalment payable in one lump sum upon Due Date.

4.4      All payments under this Agreement or contemplated hereunder, including,
         but not limited to any payments made by the Vendor in respect of
         persons employed by the Purchaser and seconded to the Vendor as
         referred to in clause 6.5.1 shall be exclusive of any Value Added Tax
         or any tax or charge levied in substitution therefor, which shall be
         payable in addition to such payments contemporaneously therewith.

4.5      All amounts payable to the Vendor by the Purchaser shall be paid by way
         of telegraphic transfer to National Westminster Bank Plc, PO Box 34, 15
         Bishopsgate, London EC2P 2AP, Sort Code 50-00-00, []*

4.6      The Purchaser shall upon completion provide the Vendor with an executed
         Bill of Exchange, drawn by the Vendor on and accepted by Barclay's Bank
         ("the Bank") in a form reasonably satisfactory to the Vendor in respect
         of and in the amount of the second instalments of both the Funding
         Contribution and the IP Management Fee, totalling []* payable by the 
         Bank on demand on the Due Date or at any time thereafter.

5        Completion

5.1      The sale and purchase shall be completed immediately upon exchange of
         this Agreement when all the matters set out in this clause 5 shall be
         effected.

5.2      The Vendor shall deliver to the Purchaser, at the offices of Medeva or
         such other address as the parties may agree, such of the Assets as are
         capable of being transferred by delivery.

5.3      The Vendor shall cause to be delivered or (if so requested by the
         Purchaser) made available to the Purchaser such documents in agreed
         form as are reasonably required by the Purchaser to complete the sale
         and purchase of the Assets.

5.4      The parties (as appropriate) shall enter into and exchange certified
         Board Minutes evidencing the approval of this Agreement and the other
         documents and transactions

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       9
<PAGE>

         hereby contemplated and duly authorising the signing thereof by the
         representatives of the parties.

5.5      In addition to the specific rights set out in clause 21, the Purchaser
         shall permit the Vendor on reasonable notice to inspect and take copies
         of all or any of the original documents delivered to the Purchaser
         pursuant to clauses 5.2 and 5.3. Such rights of inspection and copying
         shall continue for a period of seven (7) years from the Effective Date.
         Where by reason of any statutory provision or regulation the Vendor is
         required to retain the originals of any documents or records which
         relate to the Patents and/or the Know-How the Vendor may retain such
         documents or records and to fulfil its obligations in respect of the
         above by delivering to the Purchaser copies of all such documents and
         records and providing to the Purchaser the same rights to inspect and
         take copies as are provided to the Vendor under this clause 5.5.

5.6      Upon completion of the matters referred to above the Purchaser shall
         pay the amounts specified in clause 4 in accordance therewith and shall
         deliver to the Vendor the irrevocable letter of credit pursuant to
         clause 4.6 above.

6        Continuing development

6.1      The parties acknowledge and agree that it is in their best interests to
         pursue development programmes for proposals or projects currently
         existing and/or associated with the Assets. The Development Projects
         shall comprise:

6.1.1    the VR Projects; and,

6.1.2    the New Applications (as defined in clause 6.3.1 below).

6.2      The Purchaser hereby undertakes to use all reasonable endeavours
         diligently and expeditiously to pursue and develop, whether directly or
         indirectly, and/or to procure the pursuit and development of, up to and
         including clinical proof of principle stage, the Development Projects.
         Progress in respect thereof shall be reviewed and monitored at Project
         Meetings. The Purchaser shall agree with the Vendor a programme of
         development regarding each of the Development Projects and the
         Purchaser shall pursue and develop each Development Project diligently.

6.3      In performing its obligations under clause 6.2 the Purchaser shall
         throughout the term of this Agreement and for so long as the Assets
         remain capable of use or exploitation:

6.3.1    seek and pursue, to the extent agreed at Project Meetings or to the
         extent the Purchaser believes it to be commercially sound, novel or
         unexploited products, processes, or technology or new uses or
         applications thereof or any means of delivery of any of the
         aforementioned, using or incorporating the Assets whether or not in
         combination with or within such other products processes technology and
         know-how at the disposal of the Purchaser, other than the Assets (such
         novel or unexploited products, processes, services or technology being
         "New Applications").



                                       10
<PAGE>

         All New Applications shall be deemed included and comprised in
         Development Projects; and,

6.3.2    utilise, to the extent agreed at Project Meetings or to the extent the
         Purchaser believes it to be commercially sound, all products,
         processes, technology and know-how at its disposal, whether at the
         Effective Date or at any time thereafter coming under its ownership or
         control or otherwise being at its disposal.

6.4      The Purchaser hereby undertakes to notify the Vendor in writing of any
         New Application (including any commencement of a further Phase in any
         clinical development thereof) no later than the first Project Meeting
         following the same being identified, developed or discovered. The
         Purchaser shall give the Vendor further notice as soon as reasonably
         practicable should the Purchaser intend to commercialise any New
         Application or should the Purchaser be approached by any third party
         with a view to such commercialisation. []*

6.5      In consideration of the Funding Contribution payable by the Purchaser,
         the Vendor shall in conjunction with the Purchaser assist in the
         pursuit and development of the Development Projects for a period of two
         (2) years from the Effective Date, unless agreed otherwise. Such
         assistance by the Vendor shall be deemed part of and shall be subject
         always to the limitations on the Vendor's obligations contained in
         clause 3 of the Secondment Agreement, and shall otherwise be conducted
         in accordance therewith and shall include, but not be limited to:

6.5.1    at the Purchaser's cost in all things the secondment to the Vendor on
         the terms of the Secondment Agreement of up to three (3) or, with the
         agreement of the Vendor, four (4) employees of the Purchaser ("the VR
         Employees") being persons relevantly and adequately qualified to such
         an extent that they could effectively work on the Development Projects
         unsupervised . The VR Employees are subject to the approval

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       11
<PAGE>

         of Dr S Chatfield, and shall be deployed by the Vendor in the Leasehold
         Property to conduct and undertake the pursuit and development of the
         Development Projects;

6.5.2    dedicating as the Vendor considers appropriate suitably qualified
         personnel to work in conjunction with the VR Employees in undertaking
         the pursuit and development of the Development Projects; and,

6.5.3    agreeing with the Purchaser the programmes of development in respect of
         the Development Projects.

6.6      In addition to the Funding Contribution the Purchaser shall indemnify
         and keep indemnified the Vendor against any and all costs expenses or
         liability suffered or incurred by the Vendor associated with the
         secondment to the Vendor of the VR Employees. In the event that any of
         the VR Employees are dismissed or deemed to be dismissed by the Vendor
         at any time during or at the end of the period of their secondment with
         the Vendor, then the Purchaser will indemnify the Vendor against all
         and any claims for unfair dismissal, redundancy payments, wrongful
         dismissal, breach of contract and any claims for sex discrimination or
         race discrimination arising out of the unfair dismissal claims, such
         indemnity to include any monies paid to the VR Employees to settle the
         claims or as a result of awards of damages, compensation, protective or
         additional awards; the indemnity shall also cover all legal costs and
         expenses reasonably incurred by the Vendor in relation to settling,
         contesting and dealing with any such claims.

6.7      Pursuant to the indemnity in clause 6.6 above, the Purchaser shall
         reimburse the Vendor against invoices on a monthly basis for any costs
         reasonably incurred by the Vendor in relation to the VR Employees.

6.8      In respect of each of the VR Projects, unless the Purchaser shall have
         taken substantial and effective steps to pursue and confirmed its
         intention to pursue any such of the VR Projects within a period of
         twenty four (24) months from the Effective Date, then the Vendor shall
         have the right to acquire from the Purchaser such VR Project together
         with those rights granted to the Purchaser hereunder as are required to
         develop or work such VR Project on terms and conditions as might
         reasonably be agreed between the parties.

6.9      The extent of assistance and support to be provided by the Vendor
         whether through the services of the VR Employees or otherwise shall be
         in respect only of those aspects of the Development Projects which can
         be reasonably conducted and completed at the Vendor's laboratory at the
         Leasehold Property. Any development or other support, including
         clinical trials production, shall be conducted in accordance with
         clause 6.10 below.

6.10     The Vendor shall provide to the Purchaser technical development support
         including, where relevant clinical trials production, (subject to the
         Vendor's production commitments) in respect of any vaccines which the
         Purchaser may have under development, or which might be discovered by
         or come under the control of the Purchaser, and such development
         support shall be solely at the Purchaser's expense, 



                                       12
<PAGE>

         at a cost to be agreed between the parties prior to the Vendor
         affording such development support. It is the intention of the parties
         that the cost of such development support and the terms upon which it
         will be provided by the Vendor will be the subject of a Development
         Agreement between the parties on terms to be negotiated and finalised
         when appropriate.

6.11     The Vendor and the Purchaser shall convene and attend through their
         nominees development review meetings ("Project Meetings") regularly but
         no less frequently than every six months during the term of this
         Agreement. Project Meetings shall have the purpose of:

6.11.1   the compilation and agreement of programmes of development for each
         Development Project;

6.11.2   the review and monitoring of the progress or status of each Development
         Project including, but not limited to, New Applications;

6.11.3   attending to such other matters as the Project Meetings might decide.

6.12     Each party may nominate at any one time two nominees to attend Project
         Meetings. The two nominees of the Vendor (currently Dr S Chatfield and
         Dr P Cozens) and the two nominees of the Purchaser (currently Mr N
         Higgins and Dr P Laing) shall constitute the first Project Meeting. The
         said nominees shall by agreement set the agenda for each meeting and
         shall be free to invite the attendance of such personnel of the Vendor
         or Purchaser as they see fit. The Vendor and the Purchaser shall
         consider and discuss within the Project Meetings such matters as either
         party may think relevant regarding the seeking and pursuit of New
         Applications and Development Projects, the []* Project and the
         utilisation of the Assets, and strive to reach agreement in respect
         thereof. Failing agreement, and having provided reasonable
         justification for not agreeing, the Purchaser shall be responsible for
         development decisions in respect of the Development Projects, and the
         Vendor shall be responsible for development decisions in respect of the
         []* Project.

7        []* Project

7.1      In respect of the []* Project the Purchaser acknowledges and
         agrees that the Vendor shall retain control of and continue the
         development of such project, unless and until such project is
         terminated, either because they have been successful or because the
         Vendor no longer wishes to proceed with them.

7.2      In the event that an []* Project is successfully completed the
         benefits arising from such exploitation shall be dealt with pursuant to
         clauses 14.3 and 14.4. The Vendor shall be entitled to utilise an
         appropriate portion of the Funding Contribution in the carrying out of
         the []* Project.

7.3      The Purchaser hereby acknowledges and agrees that the Vendor has and
         shall retain at all times (subject to the grant back provisions of
         clause 14.4), all rights in and to the []* Project and any and
         all products, processes and technology that might

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       13
<PAGE>

         be comprised therein or arise as a result of the pursuit or development
         thereof and, for the avoidance of doubt, the Purchaser shall obtain no
         rights of whatsoever nature in the []* Project, regardless of any
         input or assistance it might provide in the pursuit or development
         thereof, other than in respect of any express rights to which it might
         be entitled in accordance with clause 14.3 or 14.4 hereof.

7.4      The Purchaser hereby grants irrevocably to the Vendor or its nominee
         the first option to the exclusion of any other person to acquire from
         the Purchaser the exclusive rights to market any and all []*
         products, processes or technology (other than in respect of the
         []* Project) developed acquired or controlled by the Purchaser,
         whether or not the same utilises involves or comprises the Assets or
         any part thereof or arises from conduct of the Development Projects.
         Such right as is granted to the Vendor is a right to acquire the said
         marketing rights at a consideration to be negotiated, but which in no
         event shall be more than the then prevailing market rate for such
         rights, the parties appreciating and intending to take account of the
         contribution made by the Vendor to the Purchaser's ability to develop,
         acquire or control the said product, process or technology, including
         but not limited to the Vendor supplying research and clinical trial
         materials, and the implementation and transfer of the Know-How, and
         such other information assistance, and guidance as the Vendor may have
         supplied. For the avoidance of doubt, the right granted to the Vendor
         by the Purchaser hereunder shall be a continuing right of first option
         in respect of each product, process or item of technology so developed,
         acquired or controlled by the Purchaser, regardless of whether or not
         the Vendor has exercised the right granted to it in respect of such
         products, processes or technology previously identified or notified to
         it.

8        Vendor's further rights and option to acquire rights

8.1      The Purchaser hereby grants irrevocably to the Vendor or its nominee
         the right to negotiate with the Purchaser (or such other party as might
         be the beneficial owner thereof) marketing rights for all products,
         processes or technology (including any commencement of a further Phase
         in any clinical development thereof), other than in respect of
         []*, which might be identified, developed or come under the
         control of the Purchaser and which fall within the VR Field and arise
         as a result of the conduct of the Development Projects. In relation
         thereto, the Purchaser shall notify the Vendor in writing no later than
         the first Project Meeting following such products process or technology
         being developed identified or acquired. The Purchaser shall give the
         Vendor further notice as soon as reasonably practicable should the
         Purchaser intend to commercialise any such product process or
         technology or should the Purchaser be approached by any third party
         with a view to such commercialisation. []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       14
<PAGE>

         []*

8.2      The Vendor's rights and options contained in clauses 7 and 8 may be
         assigned by the Vendor without consent to any purchaser of the Vendor's
         vaccine business or a substantial part thereof, provided that such
         right to assign is exercised by the Vendor on or before 30 June 1997
         after which date the Vendor's right to assign such rights and options
         shall lapse.

9        []*

10       Manufacture by Vendor

10.1     For so long as the Purchaser shall be meeting its obligations regarding
         the Funding Contribution or for so long as it shall continue to fund
         the []* Project, the Vendor shall continue to supply to the
         Purchaser for the sole purpose of conducting

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       15
<PAGE>

         the []* Projects, batches of []* virus antigens of such strains 
         and in such quantities as the Vendor might reasonably be expected 
         to supply in accordance with the Purchaser's requests.

10.2     The Vendor's obligations to supply hereunder shall be subject to the
         Vendor's production commitments and it is acknowledged and agreed by
         the Purchaser that any such request from the Purchaser does not oblige
         the Vendor to embark on []* virus antigen production chiefly or
         solely for the purposes of meeting the Purchaser's requirements under
         this Agreement.

11       Intellectual property

11.1     In consideration of the payment of the IP Management Fee by the
         Purchaser, as from the Effective Date and for a period of two (2) years
         thereafter ("the Management Period"), the Vendor shall diligently
         assume the management of the `A', `B' and `C' Patents, , comprising
         prosecution and maintenance thereof (including the defence of
         opposition and revocation proceedings) and shall promptly pay all
         renewal and other fees and costs thereof actually incurred or where the
         last due date for payment falls within the Management Period.

11.2     The Vendor shall consult with and keep the Purchaser informed regarding
         the conduct of the management of the `A', `B' and `C' Patents, , taking
         account of all reasonable requests of the Purchaser.

11.3     Without prejudice to the generality of clause 11.1 the Vendor shall
         diligently prosecute to grant all subsisting patent applications within
         the `A', `B' and `C' Patents, and use its reasonable endeavours to
         secure the broadest monopoly reasonably obtainable consistent with
         avoiding serious prejudice to the validity of such granted patents.

11.4     Upon expiry of the Management Period:

11.4.1   the Purchaser shall assume all responsibility for the management of the
         `A' Patents and shall consult with and keep the Vendor informed
         regarding the conduct thereof, taking account of all reasonable
         requests of the Vendor;

11.4.2   the Purchaser shall assume all responsibility for the management,
         subject to the requirements of the []* Agreement, of the `B'
         Patents and `C' Patents, with the costs thereof to be borne jointly
         between the Purchaser and the Vendor. The Purchaser shall consult with
         and keep the Vendor informed regarding the conduct of the management of
         the `B' Patents or the `C' Patents thereof taking account of all
         reasonable requests of the Vendor;

11.4.3   the Vendor shall transfer or make available to the Purchaser all
         documentation records and information reasonably necessary to enable
         the Purchaser to assume management of the Patents, other than the `D'
         Patents;

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       16
<PAGE>

11.4.4   The parties shall jointly bear any opposition or revocation costs
         incurred in respect of any of the Patents, other than the `D' Patents.

11.5     Notwithstanding anything to the contrary expressed or implied herein
         upon the expiry of the Management Period all responsibility for
         conducting those duties specified in or contemplated in clauses 11.1 to
         11.3 herein shall pass to the Purchaser, subject to the requirements of
         the []* Agreement, and further provided that the Purchaser shall
         notify and consult with the Vendor and take into account the Vendor's
         reasonable requirements in respect of those Patents and Intellectual
         Property Rights in which the Vendor retains any interest whether by way
         of ownership, licence, or contingent right to acquire any such rights.

11.6     Any and all Intellectual Property Rights of whatsoever nature arising
         as a result of the pursuit or development of the Development Projects
         and/or the use or exploitation of the Assets shall be dealt with as
         follows:-

11.6.1   all such Intellectual Property Rights other than those arising from the
         []* Project shall be the sole and exclusive property of the
         Purchaser subject to any licence rights to the Vendor specified in
         clause 11.7 below;

11.6.2   all such Intellectual Property Rights which arise from or relate to the
         []* Project shall be the sole and exclusive property of the Vendor.

11.7     The Purchaser shall grant to the Vendor the following licence rights in
         respect of any such Intellectual Property Rights to which the Purchaser
         becomes entitled in accordance with clause 11.6.1:

11.7.1   where such Intellectual Property Rights have application in the
         []* Field, the Purchaser shall grant to the Vendor an exclusive
         world wide royalty free irrevocable licence without limit of time and
         with the right of sub-licence for all uses in the []* Field.

11.8     Any improvements developed by the Purchaser falling within the scope of
         the `A', `B' or `C' Patents shall belong to the Purchaser subject to a
         royalty free irrevocable non-exclusive licence in favour of the Vendor
         within the []* Field. Any improvements developed by the Purchaser
         falling within the scope of the `D' Patents shall belong to the Vendor
         subject to an exclusive royalty free licence in favour of the Purchaser
         within the `D' Field. All other improvements shall belong exclusively
         to the party making the same. Should the Vendor be assigned the `B'
         Patents or any of them from []* or the proprietor thereof, with the
         right to assign attached thereto, the Vendor will assign to the
         Purchaser at the Purchaser's cost any such `B' Patent, subject to any
         consents restrictions reservations or third party rights attached
         thereto Any such `B' Patent subject to any such consents, restrictions,
         reservations or third party rights shall for the purposes of this
         Agreement be deemed an `A' Patent upon its assignment

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       17
<PAGE>

12       Interest in Patents


12.1     Following the expiry of the Management Period the Purchaser shall
         forthwith notify the Vendor should, in respect of any of the `A'
         Patents, the Purchaser elect to abandon the prosecution of any
         application in any jurisdiction with the effect that all rights
         emanating from any application based on or claiming priority from any
         patent within any patent family denoted by an MPC number referred to in
         the first column of Schedule 1 in that jurisdiction would be lost
         leaving no rights outstanding, or the Purchaser elects not to renew any
         granted patent. Upon receiving such notification from the Purchaser,
         the Vendor may, within 30 days of receipt of such notice, inform the
         Purchaser that the Vendor desires such Patent to be assigned to it and
         the Purchaser shall at the Vendor's cost, and for the consideration of
         (L)1, assign such Patent to the Vendor and shall transfer and or
         make available to the Vendor all documentation records and information
         reasonably necessary to enable the Vendor to assume management of any
         such `A' Patents. Until such assignment is effected and appropriately
         recorded the Purchaser shall ensure that the said Patent shall be
         maintained and shall not lapse nor be abandoned.


12.2     In respect of any one or more of the `B' Patents or the `C' Patents,
         the Purchaser may notify the Vendor in writing at any time during the
         term of this Agreement that it no longer requires a sub-licence from
         the Vendor in respect of such Patents whereupon such Patents shall be
         deemed deleted from Schedule 1 hereto and the Purchaser shall no longer
         be responsible for any costs related to such Patents and any
         sub-licence under the relevant Patents shall be deemed revoked.
         Following service of such written notice the Vendor may in its absolute
         discretion abandon or otherwise deal with such Patents as it sees fit.


12.3     At any time following the date of this Agreement the Vendor may give
         notice to the Purchaser that any of the Patents is of no further
         interest to the Vendor and, within ninety (90) days of receipt of such
         notice, the Purchaser shall by counter-notice inform the Vendor either
         that:


12.3.1   the Patent may be abandoned forthwith; or


12.3.2   subject to the Vendor's existing commitments to third parties (if any)
         the Purchaser desires the Patent to be assigned to it and, subject to
         the Vendor being free to assign as requested, the Vendor shall at the
         Purchaser's cost assign such Patent to the Purchaser on terms and
         conditions to be agreed.

13       Vaccine research unit funding

13.1     The Purchaser hereby agrees to pay to the Vendor by way of contribution
         to the funding of Medeva's vaccine research unit at Imperial College
         the Funding Contribution being an amount of one million pounds sterling
         ((L)1,000,000) payable in two equal yearly instalments of
         (L)500,000 (five hundred thousand pounds) per annum in accordance
         with clause 4.2.

                                       18
<PAGE>

13.2     The Funding Contribution shall be an unconditional and non-refundable
         payment by the Purchaser and may be applied by the Vendor and/or
         Medeva's vaccine research unit as they see fit, provided such
         application of the Funding Contribution shall be reasonably related to
         the conduct of research or the acquisition maintenance replacement or
         repair of facilities of Medeva's vaccine research unit.


14.      Benefits from exploitation

14.1     Should the Purchaser its Affiliates or connected persons license sell
         or otherwise dispose of or derive in any way any income or revenue from
         any product process or technology resulting from use of or exploitation
         in any way of the VR Technology and/or the Development Projects (other
         than in relation to Helicobacter Pylori which shall be dealt with in
         accordance with clause 14.2 or the []* Projects, which shall be
         dealt with in accordance with clauses 14.3 and 14.4), the Purchaser
         shall pay to the Vendor an amount equal to []* of the Net Consideration
         (as herein defined), whether in money or money's worth, received by 
         the Purchaser its Affiliates or connected persons in respect of any 
         such licence sale disposal use or exploitation. Such percentage of 
         Net Consideration shall be payable by the Purchaser to the Vendor as 
         follows:

14.1.1   where such consideration is payable in a lump sum or by instalments
         within 30 days of such lump sum or instalment being payable and/or,

14.1.2   where such consideration is payable by way of royalty or in any other
         manner, within 30 days of the due date for payment of the said royalty
         or other payment.

14.2     Should the Purchaser its Affiliates or connected persons license sell
         or otherwise dispose of or derive in any way any income or revenue from
         Helicobacter Pylori and any product, process or technology in relation
         thereto, resulting from use of or exploitation in any way of the
         Assets, the Purchaser shall pay to the Vendor an amount equal to []*
         of the Net Consideration, whether in money or money's worth, received
         by the Purchaser its Affiliates or connected persons in respect of any
         such licence sale disposal use or exploitation. Such percentage of 
         Net Consideration shall be payable by the Purchaser as follows:-

14.2.1   where such consideration is payable in a lump sum or by instalments
         within 30 days of such lump sum or instalment being payable; and/or

14.2.2   where such consideration is payable by way of royalty or in any other
         manner, within 30 days of the due date for payment of the said royalty
         or other payment.

14.3     Should the Vendor its Affiliates or connected persons license sell or
         otherwise dispose of or derive in any way any income or revenue from
         any product, process or technology arising from the []* Projects
         the Vendor shall pay to the Purchaser an amount equal to []* of the 
         Net Consideration whether in money or money's worth, received by the
         Vendor its Affiliates or connected persons in respect of any such 
         licence, sale or other disposal. Such percentage of Net Consideration
         shall be payable by the Vendor to the Purchaser as follows:-

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       19
<PAGE>

14.3.1   where such consideration is payable in a lump sum or by instalments,
         within 30 days of such lump sum or instalment being payable and/or

14.3.2   where such consideration is payable by way of royalty or in any other
         manner within 30 days of the due date for payment of the said royalty
         or other payment.

14.4     Should in respect of the []* Projects the Vendor decide that it
         does not wish to continue with any or all of the []* Projects, or
         should the Vendor have taken no substantial or effective steps to
         pursue any or all of the []* Projects within a period of twenty
         four (24) months from the Effective Date, then in any such event the
         Purchaser shall be entitled to acquire from the Vendor the right to
         exploit any process, product or technology arising from any such
         []* Project for the sum of []* subject to any third party consents
         rights or obligations, existing or contingent, in relation thereto. 
         At the Purchaser's request and cost in all things, in relation to 
         any exploitation of output from the []* Project acquired by the 
         Purchaser pursuant to this clause 14.4, the Vendor shall where possible
         and subject to any consents required, grant a sub-licence of the 
         Vendor's rights in the patents and know-how licensed to the Vendor 
         under the []* Agreement to any third party nominated by the Purchaser.
         In such case where the Purchaser has acquired such a right from the 
         Vendor, should the Purchaser its Affiliates or connected persons 
         license, sell or otherwise dispose of or derive in any way any income
         or revenue from any rights arising from the []* Project or any product,
         process or technology in relation thereto, the Purchaser shall pay to 
         the Vendor an amount equal to []* of the Net Consideration, whether 
         in money or money's worth, received by the Purchaser its Affiliates 
         or connected persons in respect of any such licence, sale or other 
         disposition. Such percentage of Net Consideration shall be payable by 
         the Purchaser as follows:

14.4.1   where such consideration is payable in a lump sum or by instalments,
         within 30 days of such lump sum or instalment being payable and/or

14.5     where such consideration is payable by way of royalty or in any other
         manner within 30 days of the due date for payment of the said royalty
         or other payment.

14.6     "Net Consideration" shall for the purposes of this Agreement mean all
         gross income or revenue received whether in money or money's worth
         less:

14.6.1   costs of manufacture; and

14.6.2   reasonable direct sales and marketing costs, but in no event shall
         there be deducted any costs of development nor deduction of other costs
         which would have the intention or effect of recovering capital
         expenditure whether for the Assets or any other assets utilised in the
         development of the products processes or technology in respect of which
         such revenue or income is derived; and

14.6.3   []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       20
<PAGE>

14.7     []*

14.8     For the purposes of this Agreement, "connected persons" shall mean in
         respect of each party, persons (not being Affiliates) subject to the
         influence or effective control, whether direct or indirect, of that
         party or its Affiliates, to the extent that such person is effectively
         an Affiliate of that party.

15       Guarantee

15.1     In consideration of the Purchaser entering into this Agreement and
         subject to 15.2 below Medeva hereby guarantees as guarantor but not as
         primary obligor to the Purchaser the performance and observance by the
         Vendor in all material respects of its obligations under this Agreement
         and any agreement or other document entered into with the Purchaser
         pursuant hereto.

15.2     Nothing in this Agreement shall make the Vendor liable in respect of
         anything done or omitted to be done on or following the Effective Date
         by the Purchaser and the Purchaser shall indemnify the Vendor in
         respect of any liability (which liability shall include without
         limitation, all losses, costs, claims, expenses, damages, legal and
         other professional fees and expenses on a party and party basis) which
         it may incur as a result of anything so done or omitted to be done
         other than in respect of any liability or indemnity arising in respect
         of any express provision hereof.

15.3     In consideration of the Vendor entering into this Agreement and subject
         to 15.4 below Peptide hereby guarantees as guarantor but not as primary
         obligor to the Vendor the performance and observance by the Purchaser
         in all material respects of its obligations under this Agreement and
         any agreement or other document entered into with the Vendor pursuant
         hereto.

15.4     Nothing in this Agreement shall make the Purchaser liable in respect of
         anything done or omitted to be done on or following the Effective Date
         by the Vendor and the Vendor shall indemnify the Purchaser in respect
         of any liability (which liability shall include without limitation, all
         losses, costs, claims, expenses, damages, legal and other professional
         fees and expenses on a party and party basis) which it may incur as a
         result of anything so done or omitted to be done other than in respect
         of any liability or indemnity arising in respect of any express
         provision hereof.

16       Regulations

16.1     The Vendor and the Purchaser acknowledge that the transfer of rights
         and assets pursuant to this Agreement may constitute a transfer subject
         to the Regulations and accordingly that the terms and conditions,
         rights, benefits and obligations of and to some or all of the employees
         engaged by the Vendor in conducting research in respect of the Assets
         may transfer pursuant to such regulations to the Purchaser. Accordingly
         the Purchaser agrees with the Vendor that if for any reason the
         Regulations should operate so as to transfer the contract of employment
         of any 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       21
<PAGE>

         person employed by the Vendor the Purchaser will indemnify and keep
         indemnified the Vendor from and against any liability which the Vendor
         may incur in connection with or arising out of its dismissal of any
         such person or the termination of the contract of employment relating
         to any such person or the transfer of the contract of employment of any
         such person including but not, limited to claims for notice pay,
         redundancy payments, protective awards, additional awards, compensation
         for unfair dismissal, sex discrimination and/or race discrimination and
         damages for breach of contract. Such indemnity shall include all costs
         and expenses, including legal costs and expenses, reasonably incurred
         by the Vendor in settling, contesting and dealing with any such claims.

17       Value Added Tax

17.1     The Purchaser shall pay to the Vendor an amount equivalent to the VAT
         chargeable on the transactions contemplated in this Agreement against
         the production by the Vendor of the appropriate VAT invoice.

18       Warranties

18.1     The Vendor warrants to the Purchaser that the Warranties, save as set
         out in the Disclosure Letter, are in all material respects true and
         accurate and not misleading at the date of this Agreement.

18.2     The Vendor acknowledges that the Purchaser in entering into this
         Agreement is relying on the Warranties. Save for the Warranties the
         Purchaser is not relying on any other, undertakings, representations or
         warranties when entering into this Agreement.

18.3     The rights of and remedies available to the Purchaser in relation to
         the Warranties shall not be affected by Completion.

18.4     The liability of the Vendor in respect of the Warranties shall be
         limited by the provisions of Schedule 3.

18.5     The Purchaser warrants that as at the date hereof and save for the
         Licence Agreement ("the Mochida Agreement") entered into with Mochida
         Pharmaceutical Company, Limited ("Mochida") the Purchaser has not
         entered into any arrangements with any third parties pursuant to which
         such third parties may obtain rights over or in respect of any of the
         proprietary rights and/or information arising from the performance of
         or contemplated by this Agreement including but not limited to the
         Development Projects.

18.6     The Purchaser further warrants that the terms of the Mochida Agreement
         oblige the Purchaser to negotiate exclusively with Mochida with a view
         to granting an exclusive licence to Mochida in respect of Japan
         regarding:

18.6.1   various existing patents in which, prior to the date of this Agreement,
         the Purchaser had a pre-existing interest; and

                                       22
<PAGE>

18.6.2   other patents filed by or assigned to or exclusively licensed to the
         Purchaser in its sole name only.

18.7     The Purchaser further warrants that any licence entered into pursuant
         to the negotiations with Mochida will comply in all respects with all
         terms conditions and restrictions (whether contractual or otherwise and
         including any terms in relation to sub-licensing) to which the
         Purchaser is subject in relation to the Patents or the Know-How, and in
         so doing the Purchaser will not be in breach of the Mochida Agreement.

19       Restrictive Trade Practices Act

19.1     No provision contained in this Agreement by virtue of which this
         Agreement is registerable under the Restrictive Trade Practices Act
         1976 shall come into effect until the day after the particulars of this
         Agreement or a memorandum of it have been delivered to the Office of
         Fair Trading in accordance with the Restrictive Trade Practices Act
         1976.


20       Assignment and Sub-Licensing


20.1     The Purchaser may assign any or all of the `A' Patents and the `A'
         Patent Know-How but not the `A' Patent Know-How independently of the
         `A' Patent to which it relates with the prior written consent of the
         Vendor, which consent shall not be unreasonably withheld.


20.2     The Purchaser may license any or all of the `A' Patents and the `A'
         Patent Know How, but not the `A' Patent Know-How independently of the
         `A' Patent to which it relates and upon effecting such licences, the
         Purchaser shall notify the Vendor of the value and effect of the
         licences, their subject matter, and the identity of the licensees.


20.3     The Purchaser shall not sub-license:


20.3.1   any or all of the Purchaser's rights in the `B' Patents and the `B'
         Patent Know-How;


20.3.2   any or all of the Purchaser's rights in the `C' Patents and the `C'
         Patent Know-How;


20.3.3   any or all of the Purchaser's rights in the `D' Patents and the `D'
         Patent Know-How;


         without first obtaining in each and every case the prior written
         consent of the Vendor and in respect only of the `B' and `C' Patents
         and the `B' and `C' Patent Know-How such consent shall not be
         unreasonably withheld and further provided that the Purchaser shall not
         sub-license any of the `B', `C' or `D' Patent Know-How independently of
         the Patents to which it relates.


20.4     The Purchaser shall be prohibited from assigning any or all of its
         rights under the `B', `C' or `D' Patents or the `B', `C' or `D' Patent
         Know How, or this Agreement in whole or in part provided that the
         Purchaser, subject where appropriate to any consents required under the
         []* Agreement, may otherwise freely assign this Agreement or the
         benefit of any licences or sub-licences granted hereunder to its
         Affiliates for so

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       23
<PAGE>

         long as they remain such and provided that such companies are
         registered in England or Wales and/or that the terms of this Agreement
         will be given effect to and expressed to be enforceable against such
         assignee within England and Wales and/or the Purchaser and/or Peptide
         shall guarantee performance of this Agreement and any licence or
         sub-licence granted hereunder by such Affiliate.

20.5     Each of the Purchaser and the Vendor shall notify the other promptly on
         completion thereof any assignment, licence or sub-licence effected.


20.6     Any purported assignment or sub-license by the Purchaser in
         contravention of this clause 20 shall be voidable by the Vendor. 

21      Access to Records

21.1     Within such records and other documentation to be retained by the
         Vendor and/or to be transferred to the Purchaser in accordance with
         clause 5.5. herein there may be information of a confidential nature or
         which does not relate exclusively to the Assets in the VR Field. Such
         information insofar as it is in or comes into the possession of the
         Purchaser or its employees or agents, and is covered by confidentiality
         agreements between the Vendor or its Affiliates and third parties shall
         be subject to the confidentiality provision in clause 30 of this
         Agreement and, where the terms of such third party confidentiality
         agreements are known to or are disclosed to the Purchaser it shall
         ensure that it will not do anything or omit to do anything which if
         done or omitted to be done by the Vendor or its Affiliates would amount
         to a breach of such confidentiality agreement. 

21.2     Upon request, the Purchaser shall grant to the Vendor access to such 
         records and relevant personnel upon reasonable notice and such 
         information and/or assistance as the Vendor might require shall be 
         provided during normal working hours unless the Purchaser and the 
         Vendor otherwise agree.

22       Announcements

22.1     The parties agree that save for the press announcement in the form to
         be agreed which shall not be released in any event prior to this
         Agreement coming into force, no public announcement of any kind shall
         be made in respect of this Agreement except as specifically agreed in
         writing between the Vendor and the Purchaser, or except to the extent
         that an announcement is required by the Stock Exchange. Any
         announcement by any party shall in any event be issued only after prior
         consultation with the other.

23       Costs

23.1     All expenses incurred by or on behalf of the parties, including all
         fees of agents, solicitors and accountants employed by either of the
         parties in connection with the negotiation, preparation and execution
         of this Agreement shall be borne solely by the party which incurred
         them.

                                       24
<PAGE>

24       Further Assurance

24.1     The Vendor hereby agrees at the cost of the Purchaser that it will do
         all such acts, execute all such documents and the like that may be
         reasonably necessary to perfect title to the `A' Patents in the name of
         the Purchaser and to enable the Purchaser to record such assignments in
         patent offices or equivalent office records and with respect to the `B'
         Patents, the `C' Patents and the `D' Patents, each party hereby agrees
         to provide at the other's cost all reasonable assistance to that other
         to register the licences granted hereunder, where so required or
         desirable under national laws, in the name of the other and where
         necessary to execute such confirmatory assignments or short form
         licences as may be necessary.

25       Taxation

25.1     The Purchaser or the Vendor shall be entitled to deduct or withhold any
         amounts in respect of taxation which are required by law or practice of
         the relevant tax authority to be deducted or withheld from any payments
         made under this Agreement

26       Communications

26.1     All communications between the parties with respect to this Agreement
         shall be in writing and will be effectively given if delivered to the
         address of the intended recipient as set out below or sent by facsimile
         to the intended recipient at the following numbers:




MEDEVA PLC                                  10 St James's Street
                                            London SW1A 1EF
                                            Attn: Company Secretary
                                            Fax:  0171 930 1516
                    
EVANS MEDICAL LIMITED                       Evans House
                                            Regent Park
                                            Kingston Road
                                            Leatherhead
                                            Surrey KT22 7PQ
                                            Attn: Managing Director
                                            Fax:  01372 364 018

                                       25
<PAGE>

PEPTIDE THERAPEUTICS GROUP PLC              321 Cambridge Science Park
                                            Milton Road
                                            Cambridge
                                            CB4 4WG
                                            Attn: Company Secretary
                                            Fax:  01223 423 111
                                 


PEPTIDE THERAPEUTICS LIMITED                321 Cambridge Science Park
                                            Milton Road
                                            Cambridge
                                            CB4 4WG
                                            Attn: Company Secretary
                                            Fax:   01223 423 111
                                 
         Provided that any party hereto may give notice in accordance with this
         clause to the other parties hereto of a new address or facsimile number
         to be used for the purposes of this clause.

26.2     A notice, approval, consent or other communication shall take effect
         from the time it is received (or, if earlier, the time it is deemed to
         have been received in accordance with sub-clause 26.3) unless a later
         time is specified in it.

26.3     A letter or facsimile is deemed to be received:

26.3.1   in the case of a posted letter, unless actually received earlier, on
         the third (7th, if posted to or from a place outside the United
         Kingdom) day after posting;

26.3.2   in the case of facsimile, on production of a transmission report from
         the machine from which the facsimile was sent which indicates that the
         facsimile was sent in its entirety to the facsimile number of the
         recipient.

27       Entire agreement and schedules

27.1     This Agreement and the Schedules the Disclosures and all documents
         entered into pursuant hereto shall constitute the entire agreement and
         understanding between the parties with respect to all matters which are
         referred to.

27.2     All the Schedules form part of this Agreement.

27.3     This Agreement shall be binding upon each party's successors and
         assigns.

28       Invalidity

28.1     If any term or provision in this Agreement shall in whole or in part be
         held to any extent to be illegal or unenforceable under any enactment
         or rule of law, that term or provision or part shall to that extent be
         deemed not to form part of this Agreement and the enforceability of the
         remainder of this Agreement shall not be affected.

                                       26
<PAGE>

29       Proper law

29.1     The construction, validity and performance of this Agreement shall be
         governed by the laws of England and the parties hereby submit to the
         non-exclusive jurisdiction of the English Courts.

30       Confidentiality

30.1     The Vendor shall, and shall procure that its Affiliates and employees,
         agents and contractors, keep confidential any and all confidential
         information of the Purchaser and shall not disclose the same to any
         third party without the prior written consent of the Purchaser.

30.2     The Purchaser shall, and shall procure that its Affiliates and
         employees, agents and contractors, keep confidential any and all
         confidential information relating to the business of the Vendor or the
         Assets (save only for such information which relates exclusively to the
         business of the Purchaser or the Assets assigned or licensed
         exclusively to the Purchaser) in its possession or knowledge prior to
         or on the Effective Date or which comes into its possession or
         knowledge thereafter, including, without limitation, the Excluded
         Assets, and shall not disclose the same to any third party (other than
         potential collaborators or licensees/sub-licensees provided such
         collaborators or licensees/sub-licensees are subject to a duty to
         retain any such information in confidence on terms no less onerous than
         those contained herein) without the prior written consent of the
         Vendor.

30.3     The obligations in clauses 30.1 and 30.2 do not apply to information:

30.3.1   which is in the public domain at the Effective Date;

30.3.2   which comes into the public domain after the Effective Date otherwise
         than by the act or omission of the recipient; or

30.3.3   which the recipient acquires from a third party (not being an Affiliate
         of the other party) who did not derive such information from the other
         party or derived such information from the other party without
         obligation of confidence; or

30.3.4   which the recipient is required to disclose by law provided that prior
         to disclosure pursuant to this sub-section the recipient shall, if
         practicable, give the other party notice of the requirement to make
         such disclosure and shall, if the other party so requests and subject
         to the other party indemnifying the recipient in a form reasonably
         acceptable to the recipient, take such steps as the other party shall
         require to resist such disclosure or to secure obligations of
         disclosure from the party to whom disclosure is so required by law.

                                       27
<PAGE>


                                   SCHEDULE 1






[]*

- ---------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended. The complete Exhibit, including the portions for which 
confidential treatment has been requested, has been filed separately with 
the Securities and Exchange Commission.


                                       28
<PAGE>




                                   SCHEDULE 2

                                   WARRANTIES


The Vendor hereby warrants and undertakes as at the date hereof to the Purchaser
in terms of the Warranties set out below subject to any qualifications fairly
disclosed in the Disclosure Letter or the Disclosure Bundle.

(i)      the Vendor is the registered proprietor of each of the `A' Patents and
         the licensee under an exclusive licence within the []* Field
         of the `B' Patents and `C' Patents and `D' Patents;

(ii)     as at the Effective Date all renewal and other fees due in respect of
         the Patents have been duly paid;


(iii)    the Vendor is not aware, having made no specific enquiry of any third
         party, of any prior art which could have a material effect on the
         validity of the Patents, other than the information disclosed in the
         files made available to the Purchaser's patent agents prior to the date
         hereof;


(iv)     the Vendor is not aware of any act that it has done that will prevent
         any application within the `A' Patents and the `B' Patents from
         proceeding to grant in the US, the European Patent Convention countries
         and Japan (but no warranty is given that such Patents will be granted);


(v)      the Vendor has not granted nor is subject to any licences (including
         any Licences of Right and/or Compulsory Licence or any other
         permissions) for use of any of the Patents to any third party;


(vi)     the Vendor has not been notified that the exercise by the Vendor of the
         Patents infringes the rights of any third party;


(vii)    the Vendor is entitled to enter into and carry out the provisions of
         this Agreement and has full power and authority to assign and/or
         license rights in respect of the Patents and other Intellectual
         Property as envisaged by this Agreement;


(viii)   so far as the Vendors are aware, having made no specific enquiry of any
         third party, there is no subsisting infringement by any third party of
         any of the Patents or other Intellectual Property assigned or licensed
         under this Agreement;


(ix)     so far as the Vendors are aware the Disclosure Letter contains true,
         complete and accurate lists of all documentation in the possession,
         custody or control of the Vendor, material to establishing the Vendor's
         acquisition of title to the `A' Patents and the `B' Patents;

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       29
<PAGE>


(x)      so far as the Vendors are aware, the Vendor is not in breach of any
         material terms of the licences or agreements relating to the Patents
         licensed and assigned under this Agreement as listed in the Disclosure
         Letter;


(xi)     []*

(xii)    []*

(xiii)   []*

(xiv)    []*

(xv)     []*

(xvi)    []*

(xvii)   []*

(xviii)  []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       30
<PAGE>



                                   SCHEDULE 3
                                   ----------

                                VENDOR PROTECTION
                                -----------------




1        The provisions of this schedule operate to limit the liability of the
         Vendor under the Warranties and references to `such liabilities' shall
         be construed accordingly.

2        No liability shall arise in respect of such liabilities unless the
         amount thereof, where aggregated with the amount of any other claim
         then or previously made by the Purchaser, exceeds the sum of
         []* in which event the whole of such claims and not merely the excess
         of []* shall be recoverable but subject always to paragraph 3 below.

3        The aggregate liability of the Vendor in respect of such liabilities
         shall not exceed []*.

4        The Purchaser confirms that it has not entered into this Agreement in
         reliance upon any representation undertaking or warranty other than the
         Warranties.

5        In the event that the Purchaser is entitled to claim under any one or
         more of the Warranties and/or any other provisions of this Agreement,
         any payments made in respect of any such claim shall pro tanto satisfy
         and discharge any claim which is capable of being made under any other
         Warranties and/or such provisions in respect of the same subject
         matter.

6        No claim shall be brought against the Vendor in respect of any breach
         of the Warranties unless (i) notice in writing of any such claim
         including details of the material facts giving rise to the claim and
         the identity of the Warranty against which the breach is alleged is
         given to the Vendor as soon as reasonably practicable after the facts
         giving rise to the claim are known to the Purchaser and (ii) any such
         notice has been given to the Vendor by the Purchaser prior to the first
         anniversary of the date of this Agreement.

7        In the event that the Vendor makes any payment in respect of any claim
         for breach of any Warranties and subsequent to the date of such payment
         the Purchaser recovers any sum including but not limited to the
         proceeds of any policy of insurance or receives any benefit which is
         referable to such payment or to the circumstances giving rise to such
         claim in respect of which such payment was made then the Purchaser
         shall forthwith repay to the Vendor such amount that is so recovered or
         referable not exceeding the amount paid by the Vendor in respect of
         such claim net of costs of any such recovery or benefit.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
                                       31
<PAGE>








                                   SCHEDULE 4
                                   ----------

                                THE ANNOUNCEMENTS
                                -----------------


                                 [TO BE AGREED]


                                       32
<PAGE>






IN WITNESS WHEREOF the duly authorised representatives of the parties have duly
executed this Agreement the date first before written.




SIGNED by  GARRY WATTS                         )
for and on behalf of MEDEVA PLC                ) GARRY WATTS
in the presence of:                            )







SIGNED by  GARRY WATTS                         )   
for and on behalf of EVANS MEDICAL             ) GARRY WATTS  
LIMITED in the presence of:                    )   
                                              







SIGNED by  JOHN ROBERT BROWN                   )
for and on behalf of PEPTIDE THERAPEUTICS      ) JOHN ROBERT BROWN
LIMITED in the presence of:                    )








SIGNED by JOHN ROBERT BROWN                     )
for and on behalf of PEPTIDE THERAPEUTICS       ) JOHN ROBERT BROWN
GROUP PLC in the presence of:                   )




                                       33


<PAGE>


                                                                    EXHIBIT 10.7


                             Dated 10 September 1997

                          PEPTIDE THERAPEUTICS LIMITED

                                      -and-

                        UNIVERSITY OF MARYLAND, BALTIMORE

                                      -and-

                                   MEDEVA PLC


         --------------------------------------------------------------
         --------------------------------------------------------------

                       ASSIGNMENT AND VARIATION AGREEMENT

         --------------------------------------------------------------
         --------------------------------------------------------------


<PAGE>

THIS ASSIGNMENT AND VARIATION AGREEMENT is made on this 10th day of September,
1997, (the "Effective Date") ("Agreement")

BY:

(1)   PEPTIDE THERAPEUTICS LIMITED a company incorporated in England and
      Wales (No. 2774777) whose registered office address is at 321 Cambridge
      Science Park, Milton Road, Cambridge, CB4 4WG England ("Peptide"); and

(2)   UNIVERSITY OF MARYLAND, BALTIMORE of 515 W. Lombard Street, Baltimore,
      Maryland 21201, USA (the "University") formerly named UNIVERSITY OF
      MARYLAND AT BALTIMORE; and

(3)   MEDEVA PLC (No. 2086530) whose registered office address is at 10 St.
      James's Street, London SW1A 1EF England ("Medeva").

WHEREAS

(A)   In January 1991, Medeva and its affiliates acquired the exclusive rights
      to use technology developed at the Wellcome Research Laboratories,
      Beckenham, Kent in the field of attenuated mutants of Salmonella typhi for
      human vaccines. These rights were licensed to Peptide by an agreement
      dated 30 January 1997 ("Peptide Agreement").

(B)   The University has the exclusive rights to use technology developed at its
      Center for Vaccine Development ("CVD") in the field of []*

(C)   By an Agreement of 20 September 1994 made between the University and
      Medeva, University and Medeva agreed to collaborate in the further
      development of []* ("The Principal Agreement").

(D)   In or around May 1995, Medeva terminated the "Project" (as that term is
      defined under the Principal Agreement) and the Principal Agreement fell
      dormant.

(E)   The parties have now agreed that Peptide take an assignment from Medeva of
      the Principal Agreement on the terms and conditions and with the
      modifications to the Principal Agreement and its schedules set out below.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                        1
<PAGE>

IT IS AGREED as follows:

1     ASSIGNMENT OF THE PRINCIPAL AGREEMENT

1.1   In consideration of Peptide agreement to assume all the obligations and
      liabilities of Medeva under the Principal Agreement from the Effective
      Date, Medeva hereby assigns and Peptide hereby accepts the assignment of
      the Principal Agreement on the terms herein (the "Assignment").

1.2  In consideration of (a) Peptide agreeing to accept the terms and
      conditions of the Principal Agreement from the Effective Date and (b)
      Medeva and Peptide accepting the terms and conditions of this Agreement,
      the University hereby consents to the Assignment without further recourse
      against Medeva for any reason whatsoever, []*

1.3   With effect from the effective Date all contractual rights and obligations
      under the Principal Agreement shall be enforceable exclusively between the
      University and Peptide as fully as if Peptide had been an original party
      to the Principal Agreement in place of Medeva from the Effective Date save
      only that

          1.3.1   the Principal Agreement shall be varied as set out in clause 2

          1.3.2   for the avoidance of doubt it is accepted by University the
                  Termination of the Project by Medeva was valid and University
                  has no claim against Medeva in relation to its work under the
                  Project. Further, such termination of the Project by Medeva
                  shall have no effect upon the new project to be commenced by
                  Peptide with Medeva following the Effective Date.

2.   VARIATIONS TO PRINCIPAL AGREEMENT

2.1  The main body of the Principal Agreement shall be varied as from the
     Effective Date as follows:

     2.1.1.    The Recitals shall be deleted;

     2.1.2     The definition for "Project Coordinator" shall be changed as
               follows:

               "Project Coordinator" means in the case of Peptide, Dr P Bedford,
               and in the case of the University, Dr. M. Levine; or such other
               person as a party may substitute from time to time by written
               notice to the other party.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       2
<PAGE>

     2.1.3     By this Agreement Medeva transfers to Peptide all rights assigned
               or licensed to it under the Principal Agreement for the []* 
               Medeva's rights in such strains have been transferred from 
               Medeva to Peptide under the terms of this Principal Agreement 
               and this Assignment and Variation of Agreement. Medeva as a 
               result of the transfer of its rights in []* will have no 
               further right to use* them except under a separate executed 
               agreement between University and Medeva or under licence from 
               Peptide in respect of arrangements entered into under the 
               Peptide Agreement.

2.2   The Schedules to the Principal Agreement shall be varied as from the
      Effective Date as follows:

      2.2.1.   Schedule 3 shall be replaced completely by the new Schedule 3
               text set out in Schedule 1 to this agreement.

3.    GENERAL

3.1   Save as set out in this Agreement, the Principal Agreement shall remaining
      full force and effect save that it is assigned as from the Effective Date
      from Medeva to Peptide.

3.2   University and Medeva agree that any Foreground Intellectual Property
      developed under the Principal Agreement prior to the Effective Date shall
      form part of the rights carried forward as Foreground Intellectual
      Property under the Principal Agreement as assigned to Peptide.

3.3   Medeva shall pass control of all Foreground Technical Information received
      from University to Peptide.

3.4   Medeva assigned to Peptide the rights granted under the Principal
      Agreement with respect to University Background Technology Information
      (BTI) and university Background Intellectual Property Rights (BIPR).
      Medeva no longer has the right to use University BTI or University BIPR
      save in respect of any arrangements entered into directly with University
      of Peptide, including under licence pursuant to the Peptide Agreement.

3.5   All licences granted by University to Medeva and by Medeva to University
      under the Principal Agreement terminate forthwith.

3.6   []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       3
<PAGE>

[]*

3.7   University hereby releases Medeva from any and all liability arising out
      of or relating to the Principal Agreement. Any liability arising from a
      breach of the continuing obligation referred to in clause 3.6 above shall
      be a liability arising under this Agreement.

3.8   Peptide will assume obligations for all the terms and conditions under the
      Principal Agreement, and this Agreement, specifically for clause 16 -
      Indemnity. Peptide's Indemnity obligations apply to actions and events
      occurring on or after the Effective Date.

Signed by their duly authorised representatives to be effective as of 10th
September, 1997.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       4
<PAGE>

                                   SCHEDULE I
                  Variations to and Replacements of Schedules
                           to the Principal Agreement

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       5
<PAGE>

SIGNED by a duly authorised officer          )
for and on behalf of                         )    /s/ N.A. Higgins
PEPTIDE THERAPEUTICS LIMITED                 )
In the presence of:-                         )
                                                      N.A. Higgins


Signature of Witness:    /s/ Paul Wallace

Name of Witness:             Paul Wallace

Address:                     11, Lisle Lane, Ely, Cambs, UK


SIGNED by a duly authorised officer          )
for and on behalf of                         )    /s/ N. A. Higgins
UNIVERSITY OF MARYLAND, BALTIMORE            )
formerly named UNIVERSITY OF MARYLAND        )        N. A. Higgins
AT BALTIMORE in the presence of:-            )


Signature of Witness:    /s/ Mary L. Leach

Name of Witness:             Mary L. Leach

Address:                     [Illegible]
                             [Illegible]
                             Baltimore, MD 21201


SIGNED by a duly authorised officer          )
for and on behalf of                         )    Wm Bogre
MEDEVA PLC                                   )
In the presence of:


Signature of Witness:    /s/ J. Murphy

Name of Witness              J. Murphy
                             Solicitor

Address:                     10 St. James's St.
                             London, SW1


                                       6
<PAGE>

      DATED                      20th September                       1994
      --------------------------------------------------------------------

                                   MEDEVA PLC

                                     -and-

                      UNIVERSITY OF MARYLAND AT BALTIMORE

      --------------------------------------------------------------------

                        BIPARTITE COLLABORATION AGREEMENT

      --------------------------------------------------------------------

                                 STRINGER SAUL
                                  Marcol House
                               293 Regent Street
                                 London W1R 7PD

                               Tel: 071-631 4048
<PAGE>

                               TABLE OF CONTENTS

<TABLE>

<S>                                                                        <C>
1.  DEFINITIONS AND INTERPRETATION  . . . . . . . . . . . . . . . . . . . . 1

2.  OBLIGATIONS OF THE PARTIES  . . . . . . . . . . . . . . . . . . . . . . 4

3.  MANAGEMENT OF THE TYPHOID PROJECTS  . . . . . . . . . . . . . . . . . . 6

4.  FOREGROUND TECHNICAL INFORMATION AND FOREGROUND INTELLECTUAL
    PROPERTY RIGHTS  . . . . . . . . . . . . . . . . . . . . . . . . . . .  7

5.  BACKGROUND TECHNICAL INFORMATION AND BACKGROUND INTELLECTUAL
    PROPERTY RIGHTS  . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

6.  OTHER INTELLECTUAL PROPERTY INTERESTS  . . . . . . . . . . . . . . . . 15

7.  ROYALTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

8.  CONFIDENTIALITY  . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

9.  WARRANTIES AND LIABILITIES  . . . . . . . . . . . . . . . . . . . . .  21

10. DURATION AND TERMINATION  . . . . . . . . . . . . . . . . . . . . . .  23

11. ASSIGNMENT  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26

12. LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26

13. FORCE MAJEURE  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

14. NOTICES  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

15. GENERAL  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

16. INDEMNITY  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
</TABLE>

<PAGE>

SCHEDULE 1(a)
Background Intellectual Property Rights of Medeva

SCHEDULE 1(b)
Background Intellectual Property Rights of University

SCHEDULE 2(a)
Background Technical Information of Medeva

SCHEDULE 2(b)
Background Technical Information of University

SCHEDULE 3
Research Programme and Budget

SCHEDULE 4(a)
Third Party Arrangements known to Medeva

SCHEDULE 4(b)
Third Party Arrangements known to University

SCHEDULE 5
Materials Release Agreement

SCHEDULE 6
Confidential Disclosure Agreement

SCHEDULE 7
Adverse conditions to be covered
<PAGE>

                       BIPARTITE COLLABORATION AGREEMENT

THIS AGREEMENT is made the 20th day of September 1994, by and between

MEDEVA PLC of 10 St James's Street, London SW1A 1EP (hereinafter referred to as
"Medeva") of the first part

AND

UNIVERSITY OF MARYLAND AT BALTIMORE of 520 W. Lombard Street, Baltimore,
Maryland 21201, USA (hereinafter referred to as the "University") of the second
part.

WHEREAS:

A)    Medeva and its Affiliates have the exclusive rights to use technology
      developed at the Wellcome Research Laboratories, Beckenham, Kent, U.K. in
      the field of attenuated mutants of Salmonella typhi for human vaccines.

B)    The University has the exclusive rights to use technology developed at its
      Center for Vaccine Development ("CVD") in the field of attenuated mutants
      of Salmonella typhi bacteria for human vaccines, and has the resources for
      clinical trials of human vaccines.

C)    The parties now wish to collaborate in the further development of
      recombinant attenuated strains of Salmonella typhi for use as a single
      dose oral typhoid vaccine and to agree to the terms and conditions
      applicable to their collaboration.

NOW THEREFORE it is hereby agreed by and between the parties as follows:

1.   DEFINITIONS AND INTERPRETATION

1.1  In this Agreement the following terms shall have the following meanings
unless the context requires otherwise:

     (a)  "Affiliate" means a company, partnership, or other entity which
          directly or indirectly controls, is controlled by or is under common
          control with the relevant party to this Agreement. "Control" means the
          ownership of more than 50% of the issued share capital or the legal
          power to direct or cause the direction of the general management and
          policies of the entity in question.

     (b)  "Background Intellectual Property Rights" means Intellectual Property
          Rights (as hereinafter defined) to be made available by a party for
          use in the

      and for the purposes of this Agreement "Animals" means all non-human
      animals;


                                       1
<PAGE>

          Typhoid Project (as hereinafter defined), pursuant to clause 2.2(c)
          including those specified in Schedules 1(a) and 1(b) attached hereto.

     (c)  "Background Technical Information" means Technical Information (as
          hereinafter defined) to be made available by a party for use in the
          Typhoid Project pursuant to clause 2.2(c) including but not limited to
          those specified in Schedules 2(a) and 2(b) attached hereto.

     (d)  "Core Typhoid Project" means the Typhoid Project as envisaged by the
          research programme and budget set out in Schedule 3 hereto as amended
          from time to time under the provisions of clause 2.2(b).

     (e)  "Field" shall mean the prevention or reduction in susceptibility to
          infectious disease in human beings by administration to human beings
          of a substance that induces immunity in human beings against such
          disease;

          For the avoidance of doubt Field shall exclude:-

          (i)  []*

          (ii) []*

      (f) "Foreground Intellectual Property Rights" means Intellectual
          Property Rights (as hereinafter defined) obtained, discovered, found,
          produced, made by or generated in the course of work on a Typhoid
          Project.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       2
<PAGE>

     (g)  "Foreground Technical Information" means Technical Information (as
          hereinafter defined) obtained, discovered, found, produced, made by or
          generated in the course of work on a Typhoid Project.

     (h)  "Intellectual Property Rights" means patents, registered designs,
          copyrights and trademarks and applications for any of the foregoing
          and any form of protection afforded by law to ideas, concepts,
          inventions and the right to apply for any of the foregoing.

     (i)  "Know-How" means any technical data and information arising directly
          from or used in the course of a Typhoid Project which a party holds as
          non-public and is capable of being employed in respect of a Second
          Generation Product (as hereinafter defined) or process by which a
          Second Generation Product is manufactured or used.

     (j)  "Net Sales" means the aggregate sales revenue of a Second
          Generation Product (determined by gross invoice price) less all
          reasonable relevant discounts, credits, transportation charges, excise
          and other taxes and duties and with allowance made for returns and
          replacements. For the purposes of calculating royalties due to the
          University pursuant to this Agreement Net Sales shall include the
          amounts referred to in the final sentence of clause 5.3(b) of this
          Agreement.

     (k)  "Project Coordinator" means in the case of Medeva, Dr S N Chatfield
          and in the case of the University, Dr M Levine; or such other person
          as a party may substitute from time to time by written notice to the
          other party.

     (l)  "Project Management Committee" means, with respect to a Typhoid
          Project, a Committee consisting of both Project Coordinators.

     (m)  "Proprietary Information" (sometimes referred to as "Confidential
          Information") shall have the meaning set forth in clause 8 of this
          Agreement.

     (n)  "Regulatory Agency" means a government body concerned with the
          granting of marketing authorisation for human vaccines.

     (o)  "Second Generation Product" means any oral typhoid vaccine which is
          derived from recombinant attenuated strains of Salmonella typhi
          possessing; []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       3
<PAGE>

     (p)  "Technical Information" means technical information, know-how,
          show-how and data of any kind including but not limited to designs,
          drawings, techniques, processes, formulae, reports, specifications,
          procedures, instructions, substances and bacterial strains.

     (q)  "Typhoid Project" means a research programme to develop and/or work or
          studies directed towards the development of a Second Generation
          Product.

1.2  Where appropriate, words denoting a singular number only shall include the
plural and vice versa.

1.3  Reference to any statute or statutory provision or regulation includes a
reference to such statute, statutory provision or regulation as from time to
time amended, extended or re-enacted.

2.   OBLIGATIONS OF THE PARTIES

2.1  (a)  Each party undertakes to carry out its duties as defined in Schedule 3
          in accordance with the timescales and costs detailed therein, or in
          modifications or supplements to Schedule 3. The costs of work carried
          out at or under the auspices of the University as specified in
          Schedule 3, or in modifications or supplements to Schedule 3 shall be
          borne by Medeva.

     (b)  Medeva shall have the right to monitor the clinical trials carried out
          at or under the auspices of the University by having representatives
          in attendance and shall have the right to audit (at reasonable times
          and at its own expense) information associated with these trials.

     (c)  Medeva shall pay the University at quarterly intervals in advance one
          quarter of the total budget for the year in which the quarter falls.
          The total budget figure for the relevant year is the figure specified
          as "TOTAL COSTS YEAR..." on page 1 of Schedule 3 (as the same may be
          modified or supplemented from time to time in accordance with the
          provisions of clause 2.2(b)).

     (d)  The provisions of 2.1(a) to (c) above shall apply mutatis mutandis
          to any additional or new Schedule drawn up pursuant to clause 2.3, and
          the work envisaged thereby.

2.2  The obligations of each party in order to carry out a Typhoid Project shall
be as follows:

     (a)  to communicate fully and promptly to the Project Coordinator of the
          other party all such Foreground Intellectual Property Rights,
          Foreground Technical


                                       4
<PAGE>

          Information, Background Intellectual Property Rights and Background
          Technical Information necessary for such other party to carry out its
          part of such Typhoid Project;

     (b)  to comply with all reasonable requests and requirements of the Project
          Management Committee consistent with the research programme and the
          budget for such Typhoid Project and in the case of the Core Typhoid
          Project the research programme and budget contained in Schedule 3;
          Medeva shall have the right either directly or through the Project
          Management Committee to give its prior approval to any decision
          designed to initiate human clinical trials. Medeva shall be entitled
          to make modifications to or to supplement the research programme and
          budget contained in Schedule 3 provided that any changes to the budget
          or to the scheduling of studies arising from such modifications or
          supplements shall be subject to the consent of the University such
          consent not to be unreasonably withheld or delayed.

     (c)  when the Project Management Committee decides to pursue any Second
          Generation Product, to contribute to such Typhoid Project Background
          Intellectual Property Rights and Background Technical Information
          which (i) such party owns, (ii) such party is not prohibited from
          contributing to such Typhoid Project pursuant to any written
          agreements such party may have with a third party that is not an
          Affiliate of such party, and (iii) is required for the construction,
          evaluation and exploitation of the Second Generation Product in
          question.

2.3  Where either party wishes to undertake work in relation to a Typhoid
Project other than the work as currently envisaged by Schedule 3 hereto (as the
same may be amended from time to time under the provisions of clause 2.2(b)),
that party shall notify the other through its Project Coordinator. If the
proposal is approved by both Project Coordinators a new document setting out the
details of the research programme and budget for such work shall be executed as
an additional Schedule to this Agreement.

2.4  In respect of the Core Typhoid Project, at least four (4) months prior 
to expiration of []* from the date of this Agreement, the parties shall enter 
into good faith negotiations to reach agreement upon a revised Schedule 3 for 
the []* of the Core Typhoid Project.

2.5  On the completion of each study in the course of carrying out a Typhoid
Project the results of such study shall be submitted to the relevant Project
Management Committee and Medeva shall have sufficient time to review such
results before the parties embark on the next stage or further study within that
Typhoid Project unless Medeva has specifically agreed in writing to proceed with
such further work in advance of having the opportunity to review such results.
Medeva shall have the right to terminate such Typhoid

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       5
<PAGE>

Project by notice in writing without proceeding to carry out any further study
or work or proceeding to commercialise a Second Generation Product. Medeva
shall be entitled to terminate a study in progress but if it does so Medeva
shall be liable, in accordance with clause 2.1(a) of this Agreement for the
costs of that study which at the time of termination have been committed to and
which have been or cannot avoid being incurred.

2.6  Medeva acknowledges that it has been provided by the University with the 
bacterial salmonella typhi strains known as []* Medeva acknowledges that the 
University owns Background Intellectual Property Rights in []* Such strains 
have been provided to Medeva under the terms of this Agreement and 
accordingly the agreements previously entered into covering the provision of 
such strains and the work carried out thereunder shall have no further force 
and effect upon the signing of this Agreement. All Know-How, Technical 
Information and Intellectual Property Rights arising from the work carried 
out pursuant to []* shall, for the purposes of this Agreement, constitute 
Foreground Technical Information and/or Foreground Intellectual Property 
Rights owned jointly by Medeva and the University.

2.7  The parties acknowledge that in the course of carrying out work on a
Typhoid Project it may become impracticable or impossible to continue due to
information indicating that the proposed Second Generation Product is not safe
or efficacious. In such circumstances if appropriate amendments or variations to
the research programme and budget are not agreed by the parties as soon as
practicable following the availability of the relevant information, the
relevant Typhoid Project shall terminate and payments to the University in
accordance with the approved budget for that Typhoid Project shall cease 3
months from the date upon which the Typhoid Project is so terminated or earlier
if mutually agreed.

3.   MANAGEMENT OF THE TYPHOID PROJECTS

3.1  The following provisions of this clause 3 apply to all Typhoid Projects
individually.

3.2  Meetings of the Project Management Committee shall normally be held at
quarterly intervals and otherwise as may be deemed necessary or desirable by the
parties. Meetings shall review the progress of Typhoid Project work performed to
date and objectives for the following months. No meetings shall be held unless
both members of the Project Management Committee (or an authorised delegate) for
that Project or work attend either by personal appearance or by teleconference
call.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       6
<PAGE>

3.3  Each party shall submit to the other party:

     (a)  Progress reports at least ten days prior to each Project Management
          Committee meeting, which shall include, but not be limited to, details
          of strains, materials, reagents and protocols developed during the
          course of such Typhoid Project work.

     (b)  Brief quarterly updates.

     (c)  On completion of sufficient clinical trials to support a product
          licence application, a full report detailing all work carried out on
          such Typhoid Project and results obtained. Such reports shall be
          prepared to standards suitable for submission to Regulatory Agencies.

3.4  The University shall submit to Medeva annual statements of expenditure on
such Typhoid Project. The form of such statements shall be approved by Medeva
but in any event shall contain sufficient information to enable the items of
expenditure to be compared with the various budgeted items of expenditure:

     (i)  in the case of the Core Typhoid Project in Schedule 3, as the same may
          be modified or supplemented from time to time in accordance with the
          provisions of clause 2.2(b); and

     (ii) in the case of any other Typhoid Project in the additional Schedule to
          be executed pursuant to the provisions of clause 2.3.

3.5  At intervals of no less than 12 months, the University, at the request of
Medeva shall allow Medeva or its agents reasonable access to such information as
they may reasonably require to audit the University's expenditure statements for
up to the preceding 3 years. Such agents, if any, shall be accountants who are
familiar with financial recordkeeping practices for institutions receiving
United States government grants, and shall be subject to the approval of the
University, which approval shall not be unreasonably withheld or delayed. Such
access shall be granted only at the University's place of business and only
during the regular business hours of the University. The University undertakes
to ensure that all relevant information which Medeva or its agents may
reasonably require to carry out such audit is maintained at the University's
place of business or is positioned there at the time of such audit. The expense
of such audit shall be borne by Medeva.

4.   FOREGROUND TECHNICAL INFORMATION AND FOREGROUND INTELLECTUAL PROPERTY
     RIGHTS

4.1  Each party undertakes to monitor Foreground Technical Information with
respect to Second Generation Products for material which may be eligible for
Intellectual Property Rights protection and to notify promptly the other party
thereof.


                                       7
<PAGE>

4.2  All Foreground Technical Information and Foreground Intellectual Property
Rights shall be owned by the party or parties which first develop such
Foreground Technical Information or Foreground Intellectual Property Rights.

4.3  (a)  In respect of Foreground Technical Information or Foreground
          Intellectual Property Rights owned solely or jointly by the
          University, the University hereby grants or agrees to grant to Medeva
          a worldwide, royalty-bearing (in accordance with the provisions of
          clause 7), irrevocable (subject to the provisions of clause 10)
          licence to use such Foreground Technical Information and Foreground
          Intellectual Property Rights within the Field, subject to the
          provisions of this clause 4 and of clause 6. Medeva shall be the
          University's exclusive licensee of such Foreground Technical
          Information and Foreground Intellectual Property Rights within the
          Field, subject to the provisions of this clause 4.

     (b)  Medeva hereby grants or agrees to grant to the University, subject
          always to the University adhering to the provision of clause 9.2, a
          worldwide, royalty-free, irrevocable (subject to the provisions of
          clause 10) license to use Foreground Technical Information and
          Foreground Intellectual Property Rights which Medeva owns exclusively
          or jointly with the University for the sole purpose of education and
          academic research but not for any work done for the benefit of an
          organisation which has an interest in commercially exploiting or
          authorising the commercial exploitation of such work.

     (c)  Such licences shall take effect as of the date that the relevant
          Foreground Technical Information or Foreground Intellectual Property
          Rights shall come into existence.

4.4  Initial Patent Protection will be sought on all Foreground Intellectual
Property Rights unless Medeva considers that initial patent protection should
not be sought, in which case the provisions of clause 4.6(a) shall apply. The
procedure for obtaining initial patent protection for Foreground Intellectual
Property Rights, up to and including UK and US priority applications, shall be
implemented by the Project Management Committee for the relevant Typhoid
Project. Such Project Management Committee may appoint either the patent
department of Medeva or an independent chartered patent agent or patent attorney
to undertake any such work under the instructions of such Project Management
Committee. For Foreground Intellectual Property Rights owned exclusively or
jointly by the University, the University shall have the right to approve such
patent agent or patent attorney such approval not to be withheld or delayed.
Where necessary the parties shall jointly or severally execute any power of
attorney or other document to enable such patent agent or patent attorney to
perform its duties hereunder efficiently. If the relevant Project Management
Committee shall


                                       8
<PAGE>

take such steps to obtain initial patent protection the costs of obtaining such
protection, including the costs of the first filing, shall be borne by Medeva.

4.5  (a)  All costs, charges and expenses incidental to or consequent upon any
          form of legal action concerning the prosecution and/or defence of the
          Foreground Intellectual Property Rights including proceedings for the
          revocation of any Foreground Intellectual Property Rights or for the
          grant of a compulsory licence thereunder shall be borne and paid by
          Medeva.

     (b)  If Medeva decides to commence any proceedings (including counterclaims
          and actions for declaratory judgment) in respect of alleged
          infringement of any of the Foreground Intellectual Property Rights,
          all costs, charges and expenses incidental to or consequent upon such
          proceedings shall be borne and paid by Medeva, the right to direct and
          settle such proceedings shall belong to Medeva and all damages and
          other sums recovered in such proceedings and any other benefit of the
          judgment and order therein shall belong to Medeva.

     (c)  The University agrees that Medeva shall have the right to use the
          University's name in any proceeding brought by Medeva pursuant to
          clause 4.5(a) and (b) so that such proceeding may be conducted by
          Medeva in the name of the University if appropriate. Medeva shall
          notify the University prior to the use of the University's name in any
          proceeding pursuant to this clause 4.5(c). The University further
          agrees to sign such documents and do whatever may be necessary and
          advisable to further the conduct of such proceeding in the name of
          Medeva and/or the University.

     (d)  If Medeva commences a proceeding in the name of the University
          pursuant to clause 4.5(c) and the University is subsequently
          countersued in such proceeding or if the University is sued by
          original action relating or arising from Medeva's use of the
          Foreground Intellectual Property Rights, Medeva at its cost shall
          defend the University and its Regents, officers, employees and agents
          in such countersuit and shall indemnify the University and its
          Regents, officers employees and agents against any and all losses
          incurred by them as a result of such countersuit.

4.6  (a)  In the event that Medeva chooses not to pursue patent protection in
          the US Patent Office, European Patent Office or Japanese Patent Office
          for any Foreground Intellectual Property Right owned exclusively or
          jointly by the University, within six months of its receipt of notice
          from the University regarding the existence of such Foreground
          Intellectual Property


                                       9
<PAGE>

          Right, Medeva shall notify the University of its decision, and the
          University may thereafter elect to pursue protection for such
          Foreground Intellectual Property Rights in such Patent Offices at its
          own expense and, in such circumstances, clauses 4.5(a) and (b) shall
          not apply. Where, in the circumstances referred to above, the
          University obtains a granted patent the provisions of clause 4.6(c)
          below shall apply.

     (b)  If Medeva pursues protection efforts in any country with respect to
          any Foreground Intellectual Property Rights owned exclusively or
          jointly by the University, and thereafter chooses to abandon such
          protection efforts in that country, it shall notify the University of
          its decision, and the University may thereafter elect to pursue
          protection in such Patent Office for such Foreground Intellectual
          Property Rights at its own expense and, in such circumstances, clauses
          4.5(a) and (b) shall not apply. Where, in the circumstances referred
          to above, the University obtains a granted patent the provisions of
          clause 4.6(c) below shall apply.

     (c)  Where in the circumstances referred to in 4.6(a) and (b) above, the
          University is successful in obtaining a granted patent as a
          consequence of Medeva choosing not to pursue such patent protection or
          abandoning its efforts to obtain such protection, the University shall
          notify Medeva in writing that such a patent has been granted and that
          such notification is made under this clause 4.6(c). Within ninety (90)
          days of notification under this clause 4.6(c), Medeva may choose to
          reimburse the University its reasonable costs of obtaining such
          granted patent and the Intellectual Property Rights covered under such
          granted patent will be part of this Agreement. If Medeva chooses not
          to reimburse the University its reasonable costs of obtaining such
          granted patent within such ninety (90) day period, Medeva shall have
          no ownership right in such patent(s) and the University shall be
          entitled to licence such patent rights to other entities which are not
          parties to this Agreement, subject to the provisions of clause 6 of
          this Agreement. In such circumstances clauses 4.5(a) and (b) shall
          not apply.

4.7  Each party shall have the right to review and comment upon any applications
filed for Foreground Intellectual Property Rights prior to filing; provided,
however, that the Project Management Committee may approve the filing of an
application for Foreground Intellectual Property Rights prior to the receipt of
comments from each party (but subsequent to giving notice to each party of such
intent to file and providing each party with a draft of the proposed filing) if
the Project Management Committee reasonably deems that such filing is necessary
to prevent the loss of rights with respect


                                       10
<PAGE>

to the subject matter of such filing to non-parties to this Agreement. Each
party shall cooperate with the other with respect to preparation of applications
and further pursuit of Foreground Intellectual Property Rights.

4.8   (a)   Medeva as exclusive or joint owner of any foreground Technical
            Information or Foreground Intellectual Property Rights shall be
            entitled, at any time, to use the same for its own profit without
            accounting to the University (except for the payment of royalties
            due pursuant to this Agreement), and shall have the right to assign
            or licence such Foreground Technical Information or Foreground
            Intellectual property Rights. Medeva shall notify the University as
            soon as practicable following any such assignment and/or granting of
            any licence of the fact that such assignment or licence has been
            entered into and the identity of the assignee or licensee.

      (b)   Medeva as licensee of any Foreground Technical Information or
            Foreground Intellectual Property Rights shall be entitled, at any
            time, to use the same subject always to the provisions of this
            Agreement. Medeva may make use of the Foreground Technical
            Information for its own profit without accounting to the University
            (except for the payment of royalties due pursuant to this Agreement)
            but subject to the provisions of this clause 4, and Medeva shall
            have the right to assign its interest or grant sub-licenses to such
            Foreground Technical Information. Medeva shall notify the University
            as soon as practicable following any such assignment and/or granting
            of any sub-licence of the fact that such assignment or sub-licence
            has been entered into and the identity of the assignee or
            sub-licensee.

      (c)   If Medeva sub-licenses or assigns its interest in any Foreground
            Technical Information or Foreground Intellectual Property Rights it
            shall ensure that any sub-licensee or assignee agrees to be bound by
            the terms and conditions of this Agreement, and shall ensure that
            any such sub-licence or assignment is granted or made on terms
            consistent in all respects with the terms and conditions of this
            Agreement and any act or omission by any sub-licensee or assignee
            which would, if done or omitted to be done by Medeva, be a breach of
            this Agreement shall be deemed to be a breach of this Agreement by
            Medeva.

5     BACKGROUND TECHNICAL INFORMATION AND
      BACKGROUND INTELLECTUAL PROPERTY RIGHTS

5.1   (a)   Subject to the provisions of this clause 5 and of clause 4, clause
            6, and of clause 7, the University hereby grants to Medeva within
            the Field the


                                       11
<PAGE>

            following rights with respect to Background Technical Information
            and Background Intellectual Property owned exclusively or jointly by
            the University:

            (i)   An exclusive worldwide licence under Background Intellectual
                  Property Rights, Background Technical Information and Know-How
                  to make, have made, use, lease, and sell (including the right
                  to assign and sub-licence) []*

            (ii)  An exclusive worldwide licence under Background Intellectual
                  Property Rights, Background Technical Information and Know-How
                  to make, have made, use, lease and sell including the right to
                  assign and sub-licence) []*

            (iii) A non-exclusive worldwide licence under Background
                  Intellectual Property Rights, Background Technical Information
                  and Know-How to make, have made, use, lease, and sell
                  (including the right to assign and sub-licence) []*

            (iv)  An exclusive, worldwide, royalty-bearing (in accordance with
                  clause 7), irrevocable (subject to the provisions of clause
                  10) licence under Background Intellectual Property Rights to
                  make, use and sell products within the Field.

            []*

      (b)   Licences of the University's Background Technical Information and
            Background Intellectual Property

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       12
<PAGE>

            Rights to Medeva shall take effect as of the date that the
            University becomes obligated to contribute such Background Technical
            Information and/or Background Intellectual Property Rights to the
            relevant typhoid Project.

5.2   (a)   Medeva shall have a right to file in the name of the University
            applications for patents, inventor's certificates and other property
            rights in the United States and foreign countries relating to the
            University's Background Technical Information and Background
            Intellectual Property Rights relevant to that Typhoid Project and
            any improvements, modifications and variations thereto, including
            but not limited to the right to file, register, prosecute and
            maintain patents and patent applications. The University will
            cooperate and execute all documents in connection with the filing
            and/or prosecution of said applications. Medeva will reimburse to
            the University its reasonable costs and expenses of such
            co-operation.

      (b)   With respect to the University's Background Technical Information
            and Background Intellectual Property Rights the provisions of clause
            5.2(a) above shall be exercised by Medeva by providing to and/or
            consulting with the University in respect of its exercise of such
            rights and allowing the University to submit the relevant
            applications for patents and other matters referred to above to the
            relevant patent attorneys and where necessary Medeva shall request
            the University to engage the patent attorneys and/or agents referred
            to in clause 5.2(c) below subject to Medeva bearing the reasonable
            costs thereof. If at any time the University shall fail to deal in a
            reasonable and expeditious manner with the submission for and
            prosecution and maintenance of such rights Medeva shall have the
            right to deal with all such matters directly itself.

      (c)   Medeva shall engage patent attorneys and/or agents to prosecute such
            applications, and Medeva shall. pay the legal expenses and
            governmental fees including maintenance fees. The University shall
            have the right to approve such patent attorneys and/or agents, such
            approval not to be unreasonably withheld or delayed. Medeva shall
            have exclusive control of the prosecution of all such applications,
            including discretion as to the amendment of claims, appeal of final
            rejections, and abandonment of any application. In the event that
            Medeva chooses to abandon any such application, it will notify the
            University of its decision to abandon, and the University may
            thereafter elect to continue prosecution of said application at its
            own expense. Medeva will notify the University at least 90 days
            before discontinuing support of any application and will pay all
            expenses


                                       13
<PAGE>

            or fees accrued in connection with the application until the
            expiration of said notice.

      (d)   Medeva shall keep the university informed as to the status of the
            applications which it has filed and will provide the University with
            copies of all patent applications, office actions and materials
            relevant to the applications.

5.3   (a)   Medeva shall have the right, at its own expense, to enforce
            patents and other property rights against persons infringing the
            University's Background Technical Information or Background
            Intellectual Property Rights in any country. The University agrees
            that Medeva shall have the right to use the University's name in any
            such action, suit, or proceeding so that such action, suit, or
            proceeding may be conducted by Medeva in the name of the University
            if appropriate. The University further agrees to sign such documents
            and do whatever may be necessary and advisable to further the
            conduct of such action, suit, or proceeding in the name of Medeva
            and/or the University.

      (b)   If Medeva commences any proceedings (including counterclaims and
            actions for declaratory judgment) in respect of any alleged
            infringement of any of the University's Background Technical
            Information or Background Intellectual Property Rights, all costs,
            charges and expenses incidental to or consequent upon such
            proceedings shall be borne and paid by Medeva, the right to direct
            and settle such proceedings shall belong to Medeva and all damages
            and other sums recovered in such proceedings and any other benefit
            of the judgment and order therein shall belong to Medeva. In
            calculating any royalties due to the University pursuant to clause 7
            of this Agreement, Net Sales shall include any damages received in
            lieu of sales revenues (after deduction of all reasonable costs,
            charges, and expenses incidental to or consequent upon the recovery
            of such damages and the proceedings relating thereto) which may be
            received by or distributed to Medeva pursuant to this clause 5.3(b),
            and clause 4.5(b) and 5.3(a).

      (c)   Medeva shall also have the right, at its own expense, to defend
            (including, at its discretion, the taking of appeals) any action,
            suit, or proceeding instituted against the University and/or Medeva
            based on any claim that practice of the University's Background
            Technical Information or Background Intellectual Property Rights
            constitutes an infringement of any letters patent or other rights of
            any other person.

      (d)   If Medeva commences a proceeding in the name of the University
            pursuant to clause 5.3(a) or 5.3(b) and


                                       14
<PAGE>

            the University is subsequently countersued in such proceeding or if
            the University is sued by original action with respect to Medeva's
            use of University Background Technical Information or Background
            Intellectual Property Rights, Medeva shall defend the University and
            its Regents, officers, employees and agents in such countersuit and
            shall indemnify the University and its Regents, officers, employees
            and agents against any and all losses incurred by them as a result
            of such countersuit.

6.    OTHER INTELLECTUAL PROPERTY INTERESTS

6.1 Subject, to all other provisions of this Agreement, Medeva hereby grants to
the University a licence to use Background Technical Information and Background
Intellectual Property Rights belonging to Medeva for the sole purpose of
education and academic research (which shall not include any work done for the
benefit of an organisation which has an interest in commercially exploiting or
authorising the commercial exploitation of such work).

6.2 In respect of licenses granted by or to one party under technical
Information or Intellectual Property Rights pursuant to this Agreement the other
party shall at the request and cost of that party execute and do all such deeds,
acts, matters and things as are requisite for securing official registration or
recordation of such licences in any jurisdiction where such registration or
recordation is desired by that party.

6.3 Medeva represents and warrants to the University that the royalty
arrangements described in Schedule 4(a) are, to the best of its knowledge and
belief at the date of execution of this Agreement, the only royalty payments
which may become due as a result of the sale of a Second Generation Product. The
University represents and warrants to Medeva that the royalty arrangements
described in Schedule 4(b) are, to the best of its knowledge and belief at the
date of execution of this Agreement, the only royalty payments which may become
due as a result of the sale of a Second Generation Product. Each party
undertakes to inform the other party of any additional third party royalties
promptly after identifying that such royalties may be applicable to a Typhoid
Project or to a Second Generation Product arising from such Typhoid Project.

6.4   (a)   In the event of CVD wishing to collaborate with or undertake
            work on or utilising Salmonella typhi strains or antigens for any
            commercial entity not party to this Agreement using Background
            Technical Information, Background Intellectual Property Rights,
            Foreground Technical Information or Foreground Intellectual Property
            Rights owned exclusively by the University, the University must
            first offer in writing to Medeva the right of first refusal to
            perform such collaboration or undertake such work with the
            University in lieu of such third party commercial entity, upon terms
            and conditions that are the same in all material respects as those
            offered by


                                       15
<PAGE>

            the University to such entity. Medeva shall have the right to
            participate in and fund all or part of the work proposed pursuant to
            this clause 6.4(a). In the event that Medeva decides not to
            participate within 90 days of its receipt of such written offer the
            University shall be entitled to proceed with such collaboration or
            undertake such work with the third party commercial entity upon
            terms and conditions that are the same in all material respects as
            those contained in the written offer to Medeva, provided that Medeva
            shall be entitled to such royalties and/or payments as may be fair
            and reasonable under the circumstances. If Medeva makes no response
            within said 90 days it shall be assumed that Medeva does not wish to
            so participate provided that Medeva has been notified that the
            relevant written offer is made by the University under this clause
            6.4(a).

      (b)   In the event of the University wishing to collaborate with or
            undertake work on or utilising (i) Salmonella typhi strains or
            antigens used in a Typhoid Project using Background Technical
            Information, Background Intellectual Property Rights, or (ii)
            Salmonella typhi strains or antigens whether or not used in a
            Typhoid Project using Foreground Technical Information or Foreground
            Intellectual Property Rights; in both cases owned jointly by the
            University and Medeva for any commercial entity not a party to this
            Agreement the University must first obtain the written consent of
            Medeva. Moreover, the University shall offer in writing to Medeva
            the right of first refusal to perform such collaboration or
            undertake such work with the University in lieu of such third party
            commercial entity, upon terms and conditions that are the same in
            all material respects as those offered by the University to such
            entity. Medeva shall have the right to participate in and fund all
            or part of the work proposed pursuant to this clause 6.4(b). Medeva
            shall have 90 days from its receipt of the University's written
            offer to notify the University (i) whether it wishes to participate
            in the collaboration or work and/or (ii) whether or not it consents
            to the University undertaking the collaboration or work with such
            commercial entity not party to this Agreement. In the event that
            Medeva decides not to participate but gives its written consent,
            then as a term of such consent; Medeva shall be entitled to such
            royalties and/or payments as may be fair and reasonable under the
            circumstances. If Medeva makes no response within said 90 days its
            consent shall be assumed provided that Medeva has been notified that
            the written offer is made under this clause 6.4(b).

      (c)   No such rights to collaborate or undertake work are available to the
            University in respect of any Foreground or Background Technical
            Information or


                                       16
<PAGE>

            Foreground or Background Intellectual Property Rights in which the
            University does not have an ownership interest.

6.5 Following execution of this Agreement any bacterial strains or other
materials (excluding products intended for use by customers of Medeva) covered
by this Agreement shall only be released to third parties under a Materials
Release Agreement the form of which shall be as that appended as schedule 5 of
this Agreement. Provided, however, that the University may modify the form of
the Materials Release Agreement as required by policies of third parties which
are academic institutions if the third parties agree to make absolutely no
commercial or non-academic use of the materials without the prior consent of
both parties to this Agreement. Each party shall, promptly upon releasing any
materials covered by this Agreement, send to the other party a copy of the
Materials Release Agreement executed by the recipient of such materials.

6.6   (a)   Medeva recognises that it is the policy of the University that the
            results (including Technical Information and related Intellectual
            Property Rights) of the work of the University employees and
            students engaged in the Project ("the Researchers") must be
            publishable. Medeva agrees that Researchers shall be permitted to
            present at symposia and national or regional professional meetings,
            and to publish in journals, theses, dissertations, and otherwise,
            the methods and results of work carried out by the Researchers in
            respect of the Typhoid Project.

      (b)   Medeva shall be furnished with accurate and complete copies of any
            proposed publication or transcript of any proposed presentation at
            least sixty (60) days in advance of the submission of such proposed
            publication or presentation to a journal, editor, or other third
            party or in the case of an oral presentation at least sixty (60)
            days prior to the date of such presentation. Medeva shall have
            forty-five (45) days after receipt of said copies to object to such
            proposed presentation or publication either because there is
            patentable subject matter which needs protection and/or there is
            confidential information of Medeva contained in the proposed
            publication or presentation.

      (c)   Any confidential information of Medeva identified by Medeva shall be
            deleted from the proposed publication or presentation unless Medeva
            consents to its inclusion (such consent not to be unreasonably
            withheld) or unless Medeva agrees to treat the confidential
            information as patentable information, as set forth in the following
            paragraph.

      (d)   In the event that Medeva objects to a Researcher's publication or
            presentation due to the proposed disclosure of patentable
            information, the Researcher shall refrain from making any
            publication or


                                       17
<PAGE>

            presentation including that patentable information for (a) one year
            from date of receipt of the objection, if the patentable information
            was developed by Medeva, or (b) ninety days from date of receipt of
            the objection, if the patentable information was developed by
            Researchers solely or in collaboration with personnel of Medeva. The
            delay in publication or presentation is to permit Medeva to file
            patent application(s) with the US Patent and Trademark Office, UK
            and/or other patent office(s) directed to the patentable subject
            matter contained in the proposed publication or presentation.

      (e)   Following publication by Researcher(s) or the University, Medeva
            shall have the right to freely publish, reproduce, and use any such
            publication subject to the terms and conditions set forth herein,
            and subject to any copyright interest of entities that are not
            parties to this Agreement.

7.    ROYALTIES

7.1. The University shall be entitled to fair and reasonable payments from
Medeva in respect of its commercialisation of Second Generation Products and/or
its commercial use or licensing of Background Technical Information, Background
Intellectual Property, Foreground Technical Information and Foreground
Intellectual Property Rights of the University. Such payments shall be
determined on a royalty basis of []* of Net Sales in the relevant jurisdictions.

7.2 Payments made to the University under this clause 7 shall be payable, 
based on Net Sales in each country in which royalty payments are due, from 
the commencement of commercial exploitation (defined as the sale of []* for 
purposes other than clinical or regulatory testing uses) in that country of 
the Second Generation Product or product as defined in paragraph 5.1(a)(iv) 
(in this clause 'product') in question:

      (a)   where the product is subject to Foreground or Background
            Intellectual Property Rights in the form of patent claim(s) which
            are owned by the University and licensed to Medeva until the expiry
            or revocation of all relevant patent claim in that country in which
            such patent exists; or

      (b)   where the product is not covered by a patent claim(s) but is
            comprised of Foreground or Background Technical Information owned by
            the University, or of Foreground or Background Intellectual Property
            Rights which are owned by the University, until Background or
            Foreground such Technical Information has entered into the public
            domain, or for a period of ten years from the date of commencement
            of commercial exploitation (as defined above in this clause 7.2) in
            any country of the EEC or the USA whichever is the

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       18
<PAGE>

            earlier.

7.3 Royalties shall be payable by Medeva to the University in United States
dollars by cheque or by electronic funds transfer to an account designated by
the University. To the extent sales may have been made by Medeva in a foreign
country such royalties shall be first determined in the currency in which the
sales to which the royalties relate are made and then if necessary converted to
their equivalent in United States dollars. The exchange rate to be used for the
purposes of conversion into United States dollars will be the most favourable
rate which Medeva can reasonably obtain from its bankers from time to time and
upon the day upon which funds are converted.

7.4 To the extent that statutes, laws, codes or government regulations
(including currency exchange regulations) shall prevent or limit royalty
payments by Medeva in any country Medeva shall render to the University annual
reports of sales in respect of which royalties are earned in such country. All
monies due and owing to the University as provided in such annual reports shall
be deposited by Medeva in a local bank in such country in an account to be
designated by the University in writing or alternatively paid to the University
or deposited in its account as directed in writing by the University in any
other country where such payment or deposit is lawful under such currency
restrictions.

7.5 Interest shall be due on payments to the University required by any
paragraph of this clause 7 that are more than thirty (30) days late, interest to
accrue at the rate of []*

7.6 Royalties shall be due from Medeva with respect to Net Sales by Medeva, its
Affiliates, its licensees, sub-licensees, assignees and any other party selling
Second Generation Products with the direct authorisation of Medeva provided
however that in respect of each individual product royalty shall only be payable
once, such payment arising on the first arms length sale of such individual
product.

7.7   (a)   During the term of this Agreement and for three (3) years
            thereafter Medeva shall keep and require each assignee, sub-licensee
            and Affiliate selling Second Generation Products by authorisation of
            Medeva to keep complete true and accurate records containing all
            particulars that may be necessary to enable royalties payable to the
            University hereunder to be determined and shall permit the said
            records to be inspected at any time during normal business hours and
            upon reasonable notice by an independent auditor appointed by the
            University for such purposes and acceptable to Medeva. Medeva shall
            not unreasonably withhold its acceptance of such auditor.

      (b)   The auditor shall report to the University only the amount of
            royalty payable to the University in the period under consideration.
            The audit shall be at

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       19
<PAGE>

            the University's expense unless the audit shows an under-payment of
            royalty due to the University of 10% or more for any six months
            royalty period (ending on either 30 June or 31 December) in the one
            year period preceding the audit, in which case the audit expense
            shall be borne by Medeva.

      (c)   Within ninety (90) days from each 30 June and 31 December of each
            year, Medeva shall deliver to the University a report of the Total
            Net Sales and the calculation of royalty due to University for the
            six month period concerned.

      (d)   With each report submitted Medeva shall pay to the University the
            royalties due and payable for the period covered by the report. Such
            reports and payments shall be sent to the University at its address
            set out in clause 14 or such other address that may be notified in
            accordance with the provisions of that clause.

8.    CONFIDENTIALITY

8.1 Any and all knowledge, know-how, show-how, practice, process or other
information including Background and Foreground Technical Information, Know-How,
and Intellectual Property Rights, disclosed or submitted to either party by the
other or arising in the course of a Typhoid Project shall be Proprietary
Information and/or Confidential Information and, subject to the provisions of
clauses 6.6 and 8.5, shall be received and maintained by the receiving party,
which in the case of Medeva shall include its Affiliates, in strict confidence
and shall not be disclosed to any third party. Neither party shall use the
other's Proprietary Information and/or Confidential Information for any purpose
other than the purposes of or as contemplated by this Agreement; provided,
however, that prior to any disclosure to a party's employees and in the case of
the University the Researchers in the course of such use, each employee or
Researcher shall be apprised of the duty to maintain in strict confidence the
Proprietary Information and/or Confidential Information and not to use it for
any purpose other than in accordance with this Agreement and the University
shall ensure that each such Researcher shall sign a confidentiality agreement in
the form attached as Schedule 6. The University's obligation to have such
agreement by Researchers shall be effective upon execution of this Agreement.

8.2 Nothing contained herein will in any way restrict or impair either party's
right to use, disclose, or otherwise deal with the other party's Proprietary
Information and/or Confidential Information which:

      (a)   at the time of its receipt is generally available in the public
            domain, or thereafter becomes available to the public through no act
            of the receiving party; or


                                       20
<PAGE>

      (b)   was independently known prior to receipt thereof, or was made
            available to such receiving party as a matter of lawful right by a
            third party.

8.3 The above obligations for confidentiality shall survive termination of this
Agreement for any reason whatsoever. With respect to each item of Proprietary
Information and/or Confidential Information, such obligations for
confidentiality shall survive until such item ceases to be confidential or 5
years from the date of termination of this Agreement, whichever is the earlier.

8.4 Each party will notify the other of any subpoena or judicial order seeking
protection or discovery of the other party's Proprietary Information and/or
Confidential Information.

8.5 Medeva acknowledges that the University, as a public agency, is subject to
Maryland laws regarding access to public information. In general, those Laws
permit the University to withhold from disclosure specific details of research
projects as well as trade secrets and/or confidential commercial information
received from other parties. Medeva asserts that their Proprietary Information
and/or Confidential Information consists of trade secrets or confidential
commercial information and the University agrees to oppose disclosure of the
Proprietary Information and/or Confidential Information in the event of a public
information request seeking the Proprietary Information and/or Confidential
Information. The University will notify Medeva of any such requests pursuant to
this clause 8.5 and will allow Medeva to participate in the opposition to the
request to the extent permitted by law.

8.6 Medeva acknowledges that under University of Maryland System policy the
University undertakes to use reasonable efforts to maintain the confidentiality
of Proprietary Information/Confidential Information but cannot accept Liability
if such efforts fail.

9.    WARRANTIES AND LIABILITIES

9.1   Each party:

      (a)   undertakes to use all reasonable endeavours to ensure the accuracy
            of all Background and Foreground Technical information and
            Intellectual property Rights provided by it pursuant to this
            Agreement and in the event of any error therein, promptly upon being
            notified of the same, or of the same coming to its notice, to use
            all reasonable endeavours to supply the appropriate corrections;

      (b)   warrants its right to disclose such Background and Foreground
            Technical Information and Intellectual Property Rights;

      (c)   Warrants that it has full corporate power and authority to enter
            into this Agreement and to enter into the transactions and
            arrangements contemplated


                                       21
<PAGE>

            hereby and to perform its obligations under this Agreement in
            accordance with the terms contained herein; and

      (d)   warrants that neither the execution of this Agreement nor the
            consummation of the transactions referred to or contemplated herein
            shall contravene the terms of that party's constitution or the terms
            of any third Party arrangements, that no registration, consent or
            approval or other action by administrative or government authority
            is required in connection with the execution, delivery and
            performance of this Agreement, and that this Agreement when executed
            by both parties and delivered will constitute the valid and binding
            obligations of such party.

9.2 The parties recognise that inventions, copyrightable works and other 
proprietary information sometime arise from research sponsored in whole or in 
part by agencies of the Federal Government. Nonetheless, the University 
represents and warrants to Medeva that (1) all activities pertaining to the 
research and basic development of []* up to the point of clinical trials in 
human subjects have been conducted by the University without the assistance 
of any direct government contract or government grant funds, and (2) []* are 
provided herein free from claim, encumbrances, and restrictions of any nature 
whatsoever by any other person, subject to any rights that the United States 
government may have. The University further agrees to take whatever steps are 
necessary to prevent rights in any Foreground Technical Information and any 
Foreground Intellectual Property Rights from arising in, or inuring to the 
benefit of, any person not a party to this Agreement, subject to any rights 
that the United States government may have.

9.3   (a)   Medeva represents and warrants to the University that it or its
            Affiliates owns all right, title and interest to all the Background
            Intellectual Property Rights described in Schedule 1(a). The
            University represents and warrants to Medeva that it owns all right,
            title and interest to all the Background Intellectual Property
            Rights described in Schedule 1(b), subject to any rights that the
            United States government may have in such Background Property
            Rights.

      (b)   Medeva represents and warrants to the University that it or its
            Affiliates owns all right, title and interest to all Background
            Technical Information described in Schedule 2(a). The University
            represents and warrants to Medeva that it owns all right, title and
            interest to all Background Technical Information described in
            Schedule 2(b), subject to any rights that the United States
            government may have in such Background Technical Information.

9.4   The provisions of this clause 9 shall survive the

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       22
<PAGE>

termination of this Agreement for any reason whatsoever.

10.   DURATION AND TERMINATION

10.1 This Agreement shall be deemed to have become effective as of the date that
it is signed, and shall continue in respect of any Typhoid Project, subject to
the provisions of this clause 10, Clause 2.5 and clause 2.7 until the completion
of that Typhoid Project, as determined by unanimous vote of such Project
Management Committee for that Typhoid Project, or until otherwise determined by
written agreement of the parties.

10.2  (a)   If Medeva having due regard for its usual business considerations,
            wishes to withdraw from that Typhoid Project in addition to its
            rights under clause 2.5 it may do so upon written notice to the
            University of its termination of interest. Upon termination under
            this clause the provision of clause 10.4 below shall apply.

      (b)   No party shall be entitled to utilise or take advantage of any right
            to withdraw from a Typhoid Project while such party is in "default"
            in respect of that Typhoid Project under clause 10.3.

10.3  In the event of either party ("the party in default");

      (a)   being in material breach of its obligations under this Agreement
            which if capable of remedy is not remedied within 60 days of notice
            from the other party requiring that it be remedied, or

      (b)   being or becoming bankrupt or insolvent or making any assignment for
            the benefit of its creditors or having a receiver, administrator, or
            administrative receiver or manager appointed in respect of its
            undertaking or any of its assets or (otherwise than as a solvent
            entity for the purpose of and followed by a merger or reorganisation
            whereunder its successors shall be fully and effectually bound by
            its obligations hereunder) commencing to be wound up,

then, and without prejudice to any other rights or remedies of either party, the
party not in default shall have the right by notice to the party in default to
terminate this Agreement and the termination shall take effect (i) in
relation only to the Typhoid Project or Typhoid Projects in respect of which the
default occurs in the case of a material breach under 10.3(a) above; or, (ii) if
the material breach relates to the Agreement as a whole or in the case of
termination under clause 10.3(b) above the termination shall apply to all
Typhoid Projects. In such event the following provisions of this clause 10.3
shall apply either to the relevant Typhoid Project or Typhoid Projects or to all
Typhoid Projects as the case may be.


                                       23
<PAGE>

      (c)   The party in default shall make available to the other party (i) any
            Foreground Technical Information and Foreground Intellectual
            Property Rights generated by the party, and (ii) any Background
            Technical Information and Background Intellectual Property Rights
            which are owned by such party in default, which are necessary for
            the purposes referred to in clauses 10.3(e) and (g) below and which
            the party in default is not prohibited from making available to the
            other party due to written agreements, existing as of the date of
            the termination notice delivered to such party pursuant to clause
            10.3(a) or (b), with any third party that is not an Affiliate of
            such party in default;

      (d)   The party in default's rights under clause 4 and clause 6 to own or
            utilise any Foreground Intellectual Property Rights and Foreground
            Technical Information shall cease;

      (e)   The other party's rights under clause 4 and clause 6 to utilise any
            of such party in default's Foreground Intellectual Property Rights
            and Foreground Technical Information shall survive and remain in
            effect, and such rights shall remain subject to any royalty
            obligations and other restrictions contained in clause 4 and clause
            7;

      (f)   The party in default's rights under clause 5.1 or clause 6.1, as the
            case may be, to utilise any of the other party's Background
            Intellectual Property Rights and Background Technical information
            shall cease;

      (g)   The other party's rights under clause 5.1(a) and (iv) or clause 6.1
            as the case may be, to utilise any of such party in default's
            Background Intellectual Property Rights and Background Technical
            Information shall survive and remain in effect, without regard to
            the restrictions contained in clauses 5 and 6 (except for clause
            6.4). In the event that the University is the party in default the
            royalty obligations in clause 7 shall be modified so that the
            University shall only be entitled to a royalty of 1% of Net Sales
            from the date of such default in respect of Net Sales in the
            country(ies) where the University holds a granted patent which would
            be infringed by the use, sale or offer to sell of the Second
            Generation Product concerned. In such circumstances Medeva shall be
            entitled to retain all royalties payable to the University (without
            prejudice to any other rights which Medeva may have at law or under
            this Agreement) up to an amount equal to the damages, losses, costs
            and liabilities which arise directly or indirectly as a result of
            the University's default.


                                       24
<PAGE>

      (h)   Where the University is the party in default Medeva's rights under
            clauses 5.1(a)(ii) and (iii) shall continue and survive subject to
            the payment of royalty in accordance with the obligations in clause
            7.

      (i)   The provisions of clauses 1, 2.6, 4.5(c) and (d), 5.3, 6.1, 6.4(c),
            6.6, 8, 9, 10, 11, 15.3 and 16 shall survive any such default by any
            of the parties.

10.4 Upon termination of this Agreement for any cause other than default under
clause 10.3;

      (a)   Each party participating in a Typhoid Project shall make available
            to the other party participating in that Typhoid Project (i) any
            Foreground Technical Information and Foreground Intellectual
            Property Rights generated by such party in the course of that
            Typhoid Project, and (ii) any Background Technical Information and
            Background Intellectual Property Rights which are owned by such
            party, which are necessary to exploit any Foreground Technical
            Information or Foreground Intellectual Property Rights generated by
            any of the parties in such Project, and which such party is not
            prohibited from making available to the other parties due to written
            agreements, existing as of the date of the termination, with any
            third party that is not an Affiliate of such party.

      (b)   Each party's rights under clause 4 and clause 6 to utilise any
            Foreground Intellectual Property Rights and Foreground Technical
            Information existing as of the date of termination shall survive
            such termination, and such rights shall remain subject to any
            royalty obligations and other restrictions contained in clause 4,
            clause 6 and clause 7;

      (c)   Each party's rights under clause 5.1 or 6.1, as the case may be, to
            utilise any of the other party's Background Intellectual Property
            Rights and Background Technical Information required to be made
            available hereunder to such party prior to the date of termination
            shall survive such termination, and such party may continue to
            utilise such Background Intellectual Property Rights and Background
            Technical Information subject to any royalty obligations and other
            restrictions contained in clause 4, clause 6 and clause 7; and

      (d)   The provisions of clauses 1, 2.6, 4.5(c) and (d), 5.3, 6.1, 6.4(c),
            6.6, 8, 9, 10, 11, 15.3 and 16 and this 10.4 shall survive any such
            termination of this Agreement.


                                       25
<PAGE>

11.   ASSIGNMENT

The University shall not assign, sub-licence, mortgage or charge any of its
right, licences or obligations under this Agreement (save as expressly provided
for herein), or grant rights hereunder or otherwise delegate the performance of
its obligations without the prior written consent of Medeva, which consent shall
not be unreasonably withheld. Medeva may, in good faith, assign its rights and
the performance of its obligations and may grant sub-licences without consent
subject to the limitations imposed by other clauses of this Agreement. In
granting any sub-licence hereunder Medeva shall ensure that the terms upon which
such sub-licences are granted contain provisions relating to the payment of
royalty consistent with the provisions of clause 7 of this Agreement and Medeva
shall take appropriate steps in the case of any breach of such provisions by
such sub-licensees.

12.   LAW

      (a)   This Agreement shall be governed by and construed in accordance with
            the laws of State of Maryland (U.S.A) without regard to the
            principles of conflicts of law, except that any issues regarding the
            licence by Medeva of Background Intellectual Property Rights shall
            be governed by English Law.

      (b)   In any suit arising pursuant to or relating to this Agreement to
            which the University is a party, the parties to this Agreement agree
            that: (i) the Federal and State Courts in the State of Maryland
            located in Baltimore City or Baltimore County shall have personal
            jurisdiction over each of them; (ii) such Courts shall have
            jurisdiction over the subject matter of any such suit; and (iii)
            such Courts shall be a proper venue for any such suit.

13.   FORCE MAJEURE

The parties shall not be responsible for failure to perform any of the
obligations imposed by this Agreement, provided such failure shall be occasioned
by fire, flood, explosion, lightning, windstorm, earthquake, subsidence of soil,
failure or destruction, in whole or in part, of machinery or equipment, or
failure of supply of materials, discontinuity in the supply of power,
governmental interference, civil commotion, riot, war, strikes, labour
disturbance, transportation difficulties, labour shortage, death, disability, or
unavailability of key research personnel, or any cause beyond the reasonable
control of the parties.


                                       26
<PAGE>

The affected party shall notify the other party as soon as practicable of the
occurrence of any of the above events. Both parties shall make every reasonable
effort to minimise the effect of force majeure upon the performance of the
Agreement.

The affected party shall notify the other party as soon as practicable of the
cessation of the relevant event. If either party shall be excused from
performance of any of its obligations for a continuous period of six (6) months
or more then the unaffected party may terminate this Agreement by seven (7)
days notice in writing provided that the relevant events continue throughout the
notice period.

14    NOTICES

Any notice, claim, demand or other communication given hereunder to be effective
shall be in writing and transmitted by certified mail, postage prepaid, or by
carrier providing a receipt of delivery to the recipient, at the addressee
stated below. Either party may notify the other in the manner set forth above at
the following addresses (or such other addresses as either party may notify to
the other in accordance with the provisions of this clause):

        UNIVERSITY       Maria C Freire, Ph.D.
                         Assistant Vice President for
                         Technology Development
                         UMAB
                         Fifth Floor
                         511 West Lombard Street
                         Baltimore, Maryland 21201

                         and copy by FAX to: 410-706-5035

                         copy to;     Susan Gillette
                                      Senior University Counsel
                                      Second Floor
                                      520 West Lombard Street
                                      Baltimore, Maryland 21201

                         and copy by FAX to: 410-706-7682

                         and to:      Dr Myron M Levine
                                      UMAB
                                      School of Medicine
                                      9th Floor - MSTF Building
                                      10 South Pine Street
                                      Baltimore, Maryland 21201

                         and copy by FAX to: 410-706-6205


                                       27
<PAGE>

        MEDEVA           Mr R Stephen Harris
                         Medeva International
                         Evans House
                         Regent Park
                         Leatherhead
                         Surrey KT22 7PQ

                         and copy by fax to:    (44 71 636 2306)

and shall be deemed to be duly given when delivered if delivered by courier or
certified mail, postage prepaid; or when sent, if transmitted by telex or
facsimile transmission (receipt automatically confirmed) during normal business
hours of recipient.

15.   GENERAL

15.1 This Agreement (which includes the content of all schedules hereto)
embodies and sets forth the entire agreement and understanding of the parties
and supersedes all prior oral or written agreements, understandings or
arrangements relating to the subject matter of this Agreement. Neither party
shall be entitled to rely on any agreement, understanding or arrangement which
is not expressly set forth in this Agreement.

15.2 This Agreement shall not be amended, modified, varied or supplemented
except in writing signed by duly authorised representatives of the parties.

15.3 In the event that either party requires the other party to execute any
further document which may be reasonably required for the purpose of recording
or memorialising any licence granted hereunder, the party receiving such request
shall promptly execute such further document provided that the terms of such
document are substantially similar to the terms of the licence granted herein
and do not operate to modify, amend or supplement in any way the terms of the
licence granted herein.

15.4 No failure or delay on the part of either party hereto to exercise any
right or remedy under this Agreement shall be construed or operated as a waiver
thereof nor shall any single or partial exercise of any right or remedy under
this Agreement preclude the exercise of any other right or remedy or preclude
the further exercise of such right or remedy as the case may be. The rights and
remedies provided in this Agreement are cumulative and are not exclusive of any
rights or remedies provided by law.

15.5 Any announcement, disclosure or publicity relating to a Typhoid Project or
the contents of this Agreement shall not be made by either party hereto without
first obtaining the written approval of the other. Nothing shall restrict a
party from making any disclosure of a Typhoid Project or the contents of this
Agreement as required by law or regulation, nor, in response to third party
enquiries, from acknowledging the existence of this Agreement as a


                                       28
<PAGE>

development agreement in respect of attenuated strains of Salmonella Typhi for
human vaccines.

15.6 Nothing herein shall constitute the relationship of employer and employee
or any partnership, and it is expressly agreed that neither party hereto will
hold itself out as an agent of the other party.

15.7 This Agreement shall inure to the benefit of and be binding upon the
parties hereto, their successors and permitted assigns. Nothing in this
Agreement, expressed or implied, is intended to confer upon any person, other
than the parties hereto, any rights or remedies under or by reason of this
Agreement.

15.8 The invalidity or unenforceability of any provision of this Agreement shall
not affect the other provisions hereof, and the Agreement shall be construed in
all respects as if such invalid or unenforceable provisions were omitted.
Furthermore, upon the request of either party hereto, the parties to this
Agreement shall add, in lieu of such invalid or unenforceable provisions,
provisions as similar in terms to such invalid or unenforceable provisions may
be possible and legal, valid and enforceable.

15.9 The captions to the clauses contained in this Agreement are for reference
only, they do not form a substantive part of this Agreement, and shall not
restrict or enlarge any substantive provision of this Agreement.

15.10 This Agreement may be executed in any number of counterparts, each of
which shall be considered an original but all of which shall constitute the
Agreement by and among the parties.

16.   INDEMNITY

      (a)   []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       29
<PAGE>

            []*

      (b)   []*

      (c)   []*

      (d)   []*

      (e)   []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

                                       30
<PAGE>

      (f)   []*

Signed by their duly authorised representatives to be effective as of 20th
September 1994.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       31
<PAGE>

                                 SCHEDULE 1(a)

               Background Intellectual Property Rights of Medeva

Schedule 1(a) - Medeva's Background Intellectual Property Rights

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       32
<PAGE>

                                  SCHEDULE 1(b)

              Background Intellectual Property Rights of University

      []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       33
<PAGE>

                                  SCHEDULE 2(a)

                   Background Technical Information of Medeva

                                       []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       34

<PAGE>

                                  SCHEDULE 2(b)

                 Background Technical Information of University

      []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       35

<PAGE>

                                   SCHEDULE 3

                         Research Programme and Budget


                                       36




<PAGE>

                   INVESTIGATIONAL PLAN FOR CLINICAL STUDIES
                      OF []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
ROLLUP OF COSTS, BY YEAR

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE 1a, CORE COSTS, []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE 1b, CORE COSTS, []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE 1c, CORE COSTS, []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE 3a, CORE COSTS, []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE 2b, CORE COSTS, []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE 2c, CORE PERSONNEL COSTS, []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

CLINICAL STUDIES WITH []*
TABLE  , []*

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

CENTER FOR VACCINE DEVELOPMENT
MEDEVA PLC

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>

                                 SCHEDULE 4(a)

                    Third Party Arrangements known to Medeva

Arrangements pursuant to which third party rights arise in respect of Background
Intellectual Property Rights and Background Technical Information:-

6.3(a) - Medeva

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       37
<PAGE>

                                 SCHEDULE 4(b)

                  Third Party Arrangements known to University

                                       []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       38
<PAGE>

                                   SCHEDULE 5

                          Materials Release Agreement

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       39
<PAGE>

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       40
<PAGE>

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       41

<PAGE>

                                   SCHEDULE 6

                       Confidential Disclosure Agreement

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       42
<PAGE>

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       43
<PAGE>

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       44
<PAGE>

                                   SCHEDULE 7

                        Adverse conditions to be covered


Coverage

[]*

Conditions

[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       45
<PAGE>

For and on behalf of MEDEVA PLC
                                                           Date: Sept. 8th, 1994

/s/ R.S. Harris
- -------------------------------------------

               R.S. Harris                  (Name)
- -------------------------------------------

               Director                     (Title)
- -------------------------------------------


For and on behalf of UNIVERSITY OF MARYLAND AT BALTIMORE
                                                           Date: 9.20; 1994

/s/ DAVID J RAMSAY DM
- -------------------------------------------

DAVID J RAMSAY DM; DPhil                    (Name)
- -------------------------------------------

President                                   (Title)
- -------------------------------------------


                                       47


<PAGE>


                                                                    EXHIBIT 10.8


                          PEPTIDE THERAPEUTICS LIMITED

                                     - and -

                               NOVARTIS PHARMA AG


 ------------------------------------------------------------------------------


                             COLLABORATION AGREEMENT


 ------------------------------------------------------------------------------



<PAGE>


                                    CONTENTS

1          Definition
2          The Programme
3          Consideration
4          Intellectual Property
5          Licence Agreement
6          Confidentiality
7          Publications
8          Warranties and Undertakings
9          Announcements
10         Assignment
11         Costs
12         Further Assurance
13         Term
14         General
15         Governing Law and Jurisdiction
16         Counterparts

Schedule 1 - Research Plan
Schedule 2 - Licence Agreement




<PAGE>


THIS AGREEMENT is made on          1st November 1998

BETWEEN:-

(1)      PEPTIDE THERAPEUTICS LIMITED (No 2774777) whose registered office is at
         321 Cambridge Science Park, Milton Road, Cambridge, CB4 4WG UK
         ("PEPTIDE"); and

(2)      NOVARTIS PHARMA AG whose registered office is at Lichtstrasse 35,
         CH-4002, Basel, Switzerland ("NOVARTIS").

Together referred to as "the Parties", each singly as a "Party".

WHEREAS

(A)      Peptide has developed a system for the discovery of substrates and the
         development of inhibitors of protease enzymes known as RAPiD (Rational
         Approach to Protease Inhibitor Design);

(B)      Novartis has identified the Target Protease for which they wish to
         develop Substrates and Inhibitors as such terms are hereinafter
         defined;

(C)      The Parties have agreed that Peptide will carry out the Programme on
         the Target Protease using RAPiD and endeavour to provide a Substrate
         and Data (as hereinafter defined) to Novartis; and

(D)      Following completion of the Programme, Novartis will have the option to
         enter into a licence agreement with Peptide to allow use of the
         Substrate and Data.

IT IS AGREED as follows:



1          DEFINITION



                                       1
<PAGE>


           "AFFILIATE(S)"           In the case of either Party, a corporation
                                    or other entity which, directly or
                                    indirectly, controls, is controlled by or is
                                    under common control with, that Party. A
                                    corporation or other entity shall be
                                    regarded as in control of another
                                    corporation or entity if it owns or directly
                                    or indirectly controls more than fifty
                                    percent (50%) of the voting stock or other
                                    ownership interest of the other corporation
                                    or entity, or if it possesses, directly or
                                    indirectly, the power to direct or cause the
                                    direction of the management and policies of
                                    the corporation or other entity.

            "ARISING IP"            Any Intellectual Property resulting from the
                                    Programme carried out by Peptide including
                                    Data.

            "BACKGROUND IP"         All Intellectual Property owned by or
                                    available to either Party prior to this
                                    Agreement or generated during the term of
                                    this Agreement but not resulting from the
                                    Programme. For the avoidance of doubt the
                                    Parties recognise that Novartis owns all
                                    Intellectual Property related to the Target
                                    Protease as well as to any compounds for
                                    which Novartis discovers a pharmacological
                                    activity with respect to such Target
                                    Protease, and Peptide owns all Intellectual
                                    Property related to RAPiD.



                                       2
<PAGE>


           "CONFIDENTIAL INFORMATION"

                                    All information disclosed by one Party ("the
                                    Disclosing Party") to the other ("the
                                    Receiving Party") whether before or after
                                    the date of this Agreement which is not in
                                    the public domain including without
                                    prejudice to the generality of the
                                    foregoing; know-how and/or documents
                                    relating to or comprising the Background IP;
                                    know-how and/or documents relating to or
                                    comprising the Arising IP, and the Data and
                                    any information relating to the Disclosing
                                    Party's products, operations, processes,
                                    plans or intentions, know-how, intellectual
                                    property, inventions, trade secrets, market
                                    opportunities and business affairs.

           "DATA"                   The data relating to the Target Protease
                                    generated during the Programme by or on
                                    behalf of Peptide.

           "FRET"                   Fluorescence Resonance Energy Transfer.

           "INHIBITOR"              Any inhibitor of the Target Protease.

           "INTELLECTUAL PROPERTY"  Any and all interest whether legal or
                                    beneficial arising under the laws of England
                                    or elsewhere in patent, copyright, design
                                    right, rights in confidentiality, trade mark
                                    rights and any other analogous rights,
                                    applications for any of the foregoing (and
                                    the right to make such applications)
                                    including Know How.



                                       3
<PAGE>


           "KNOW HOW"               Technical and scientific information,
                                    necessary or useful in developing
                                    Substrates, not at present in the public
                                    domain and held in any form (including,
                                    without limitation, that comprised in or
                                    derived from drawings, data, formulae,
                                    specifications, notes, chemical compounds,
                                    computer software, component lists,
                                    instructions, manuals, reports and process
                                    descriptions) by either Party to this
                                    Agreement.

           "LICENCE AGREEMENT"      The agreement to be entered into to allow
                                    Novartis to use the Substrate and the Data,
                                    the form of which is set out in Schedule 2.

           "OPTION PERIOD"          []*

           "PRESS RELEASE"          The press release announcing the conclusion
                                    of this Agreement the wording of which
                                    having been mutually agreed by the Parties .

           "PROGRAMME"              The research programme, outlined in Schedule
                                    1, during the performance of which Peptide
                                    will apply RAPiD to the Target Protease
                                    supplied by Novartis, and the purpose of
                                    which is to identify a Substrate for the
                                    Target Protease.

           "RAPID"                  Peptide's proprietary system for discovering
                                    substrates and developing inhibitors of
                                    protease enzymes.

           "REPORT"                 A written report summarising the Data to be
                                    provided by Peptide to Novartis.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       4
<PAGE>


           "SUBSTRATE"              A FRET substrate for the Target Protease
                                    having a []* and selected by Novartis as 
                                    being suitable for use in an assay for 
                                    measuring the proteolytic activity of 
                                    Target Protease.

           "TARGET PROTEASE"        []*

2        THE PROGRAMME

2.1      Within []* of signing this Agreement, Novartis shall provide Peptide 
         with sufficient Target Protease required for the Programme and any 
         available information necessary to assay the Target Protease.

2.2      Peptide agrees to use reasonable endeavours to carry out the Programme
         and to deliver to Novartis the Report as soon as is reasonably
         practicable. In addition, if Peptide has identified a Substrate for 
         the Target Protease, Peptide will promptly supply Novartis with 
         approximately []* of the Substrate for evaluation by Novartis. In 
         any event Peptide shall provide the Report to Novartis within []* of 
         the date of this Agreement.

3        CONSIDERATION

         In consideration of Peptide carrying out the Programme Novartis 
         agrees to pay to Peptide []* exclusive of any applicable sales taxes 
         thereon within []* of (a) signing this Agreement and (b) receipt of 
         an invoice for this amount from Peptide, whichever is later .

4        INTELLECTUAL PROPERTY

4.1      For the avoidance of doubt all Background IP shall remain the property
         of the Party owning such Background IP prior to this Agreement or
         generating or acquiring it during the term of this Agreement.

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       5
<PAGE>


4.2      Any Arising IP and all Data shall be the property of Peptide.

4.3      Novartis shall have a sole licence during the Option Period to use the
         Data and the Substrate only for the purpose of internally evaluating
         the Data and the Substrate.

5        LICENCE AGREEMENT

5.1      During the Option Period Novartis may elect to enter into the License
         Agreement in the form set out in Schedule 2.


5.2      In the event Novartis elects not to enter into the License Agreement
         during the Option Period, the following terms and conditions shall
         apply, subject to Clause 6 hereof:


         (a)      Novartis shall make no further use or disclosure of the Data
                  nor of any data which has been derived, in part or in its
                  entirety, from or by use of the Data; and

         (b)      Novartis shall make no further use or disclosure of the
                  Substrate provided or identified by Peptide nor any substrate
                  derived from such Substrate nor shall it make any further use
                  or disclosure of any associated Data related to the Substrate;
                  and

         (c)      Novartis shall make no further use or disclosure of any of the
                  Confidential Information provided to it by Peptide; and

         (d)      Novartis shall return to Peptide all Data and Confidential
                  Information received by it in any format whatsoever together
                  with any and all copies of such Data and Confidential
                  Information which may have been made in any format whatsoever
                  and agrees to destroy any remaining quantities of Substrate.


6        CONFIDENTIALITY



                                       6
<PAGE>


6.1      During the term of this Agreement and for a period of []* after 
         termination or expiration of this Agreement for any reason 
         whatsoever the Receiving Party shall;

         6.1.1    keep the Confidential Information confidential;

         6.1.2    not disclose the Confidential Information to any other person
                  or entity other than with the prior written consent of the
                  Disclosing Party; and

         6.1.3    not use the Confidential Information for any purpose other
                  than the performance of its obligations or the exercise of its
                  rights under this Agreement.

The Receiving Party shall procure that its employees and the employees of its
Affiliates are made aware of and comply with all the Receiving Party's
obligations of confidentiality under this Agreement as if these employees were a
party to this Agreement.

6.2      The obligations contained in Clause 6.1 shall not apply to any
         Confidential Information which: -

         6.2.1    at the date of this Agreement or at any time after the date of
                  this Agreement is, or comes into, the public domain other than
                  through breach of this Agreement by the Receiving Party or any
                  Recipient;

         6.2.2    can be shown by the Receiving Party to the satisfaction of the
                  Disclosing Party to have been known by the Receiving Party
                  before disclosure by the Disclosing Party to the Receiving
                  Party;

         6.2.3    subsequently comes lawfully into the possession of the
                  Receiving Party from a third party under no obligation of
                  confidence to the Disclosing Party in respect of such
                  Confidential Information;

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       7
<PAGE>


         6.2.4    is subsequently and independently developed by employees of
                  the Receiving Party or Affiliates thereof who had no knowledge
                  of the Confidential Information disclosed; or

         6.2.5    is required by law, by any court of competent jurisdiction or
                  by any other appropriate regulatory body (including without
                  limitation the London Stock Exchange Limited and the Panel on
                  Take-overs and Mergers).


7        PUBLICATIONS

Neither Novartis nor Peptide shall submit for written or oral publication any
manuscript, abstract or the like which includes data or other information
generated and provided by the other Party without first obtaining the prior
written consent of the other Party, which consent shall not be unreasonably
withheld. The contribution of each Party shall be noted in all publications or
presentations by acknowledgement or co-authorship, whichever is appropriate.


8        WARRANTIES AND UNDERTAKINGS

The Parties exclude to the fullest extent permitted by law any warranties,
conditions, undertakings or terms implied by operation of law (statutory or
otherwise).

9        ANNOUNCEMENTS

The Parties agree that immediately following the execution of this Agreement the
Press Release may be released by the Parties . No other public announcement,
communication or circular (other than to the extent required by law, the London
Stock Exchange Limited or the Panel on Take-overs and Mergers or any other
regulatory body in any jurisdiction) concerning the transactions referred to in
this agreement shall be made or despatched by either Party for so long as this
Agreement continues in force without the prior written consent of the other
Party, such consent not to be unreasonably withheld or delayed.

10       ASSIGNMENT



                                       8
<PAGE>


Neither Party shall assign or transfer or purport to assign or transfer any of
its rights or obligations under this Agreement except with the prior written
consent of the other Party save that either Party may at any time assign or
transfer any of its rights or obligations under this Agreement to any of its
Affiliates. This Agreement shall be binding upon and shall inure to the benefit
of the parties hereto, their successors and assigns.

11       COSTS

Except as otherwise expressly provided in this Agreement, each Party shall pay
its own costs of and incidental to the negotiation, preparation, execution and
implementation by it of this Agreement and of all other documents referred to in
it.

12       FURTHER ASSURANCE

Each Party shall at its own cost do and execute or procure to be done and
executed all necessary acts, deeds, documents and things reasonably within its
power to give effect to this Agreement.

13       TERM

This Agreement shall come into effect on the date first written above and shall
end on expiry of the Option Period.

14       GENERAL

14.1     This Agreement constitutes the entire agreement between the Parties
         relating to the subject matter of this Agreement and supersedes all
         previous such agreements whether made orally or in writing.

14.2     No variation of this Agreement shall be valid unless it is in writing
         and signed by or on behalf of each of the Parties.

14.3     The failure to exercise or delay in exercising right or remedy under
         this Agreement shall not constitute a waiver of the right or remedy or
         a waiver of any other rights or remedies



                                       9
<PAGE>


         and no single or partial exercise of any right or remedy under this
         Agreement shall prevent any further exercise of the right or remedy or
         the exercise of any other right or remedy.

14.4     Nothing in this Agreement shall be construed as creating a partnership
         between the Parties or as constituting either Party as the agent of the
         other Party for any purpose whatsoever and neither Party shall have the
         authority or power to bind the other Party or to contract in the name
         of or create a liability against the other Party in any way or for any
         purpose.

14.5     If the performance of any part of this Agreement by either Party, or of
         any obligation under this Agreement, is prevented, restricted,
         interfered with or delayed by reason of any cause beyond the control of
         the Party liable to perform, unless conclusive evidence to the contrary
         is provided, the Party so affected shall, upon giving written notice to
         the other Party, be excused from such performance to the extent of such
         prevention, restriction, interference or delay, provided that the
         affected Party shall use its best efforts to avoid or remove such
         causes of non-performance and shall continue performance with the
         utmost dispatch whenever such causes are removed. When such
         circumstances arise, the parties shall discuss what, if any,
         modification of the terms of this Agreement may be required in order to
         arrive at an equitable solution.

14.6     Provisions of this Agreement which, by their nature, are intended to
         survive termination of this Agreement, shall so survive.




15       GOVERNING LAW AND JURISDICTION

         This Agreement shall be governed by the laws of England and Wales and
         the parties hereto hereby irrevocably submit to the jurisdiction of the
         English Courts.

16       COUNTERPARTS



                                       10
<PAGE>


         This Agreement may be executed in any number of counterparts each of
         which when executed and delivered shall be an original, but all the
         counterparts together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the parties, through their authorised officers, have
executed this Agreement as of the date first written above.

Signed on behalf of                      )
PEPTIDE THERAPEUTICS LIMITED             )



Signed on behalf of                      )
NOVARTIS PHARMA AG                       )








                                       11
<PAGE>


                                   SCHEDULE 1


                                  RESEARCH PLAN



[]*

- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       12
<PAGE>


                                   SCHEDULE 2

                                       []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a Request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       13


<PAGE>


                                                                    EXHIBIT 10.9


                                  AMENDMENT NO. 1


This amendement No. 1 to the R&D and License Agreement dated February 7, 1997 
(hereinafter "the Agreement" is made this 25th November 1998.

BY AND BETWEEN

     PEPTIDE THERAPEUTICS LIMITED, having a place of business at 321 Cambridge
     Science Park, Milton Road, Cambridge CB4 4W6, United Kingdom (hereinafter
     "PTL")

AND

     SMITHKLINE BEECHAM PLC having a place of business at New Horizons Court.
     Great West Road, Brentford, Middlesex TW8 9EP, United Kingdom (hereinafter
     "SB")

WHEREAS parties desire to extend the Research Program (as defined in the 
Agreement) by an additional []* period and to incorporate such change into 
the Agreement.

NOW THEREFORE THE PARTIES AGREE AS FOLLOWS:

1.   DEFINITIONS

     The definitions set forth in Section 1 of the Agreement shall apply to this
     Amendment N degree 1.

2.   RESEARCH PROGRAM

     2.1  The Research Program shall be extended by an additional []* and 
          Section 2.01 first sentence of the Agreement shall be amended as
          follows:

          "Subject to Sections 2.02 and 2.03 hereunder, the parties shall 
          undertake a []* collaborative research program starting from the 
          Effective Date (hereinafter "Research Program") (......./......).

     2.2  The extension of the Research Program hereunder shall not be
          considered as an execution of SP's option under Section 2.03 of the
          Agreement to start the Extended Research Program.

          In Section 2.03 of the Agreement, the words "on the second 
          anniversary of the Effective Date" shall read "at the expiration of 
          the Research Program".

     2.3  The extension of the Research Program pursuant to Section 2.1 of this

          Amendment N degree 1 shall not affect the obligations in terms of 
          resources as set forth in article 2.01 of the Agreement and for the 
          avoidance of doubt SB Bio shall not be obliged to make available 
          additional resources during the []* extension period of the 
          Research Program.

3.   All other provisions of the Agreement shall remain unchanged.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>




     IN WITNESS WHEREOF the parties through their authorised officers have
     executed this Amendment N degree 1 as of the date first written above.


           PEPTIDE THERAPEUTICS LIMITED           SMITHKLINE BEECHAM PIC



By:        /s/ N.A. Higgins             By:       /s/ [ILLEGIBLE SIGNATURE]
           ---------------------                  ---------------------------
Name:      N.A. Higgins                 Name:     President & General Manager
           ---------------------                 
Function:  Commercial Director          Function: President & General Manager
           ---------------------                  ---------------------------

Date:      2/12/98                      Date:     3/12/98
           ---------------------                  ---------------------------





<PAGE>


                                                                   EXHIBIT 10.10


                               OVERVIEW AGREEMENT

         THIS AGREEMENT is entered into as of January 25, 1999 by and between
Peptide Therapeutics Limited, a corporation organized and existing under the
laws of England and Wales ("Limited"), and Pasteur Merieux Serums & Vaccins
S.A., a societe anonyme existing and organized under the laws of the Republic of
France ("PMC"). Capitalized terms used but not otherwise defined herein shall
have the meanings assigned to them in that certain Master Agreement dated as of
March 31, 1995 by and between PMC and OraVax, Inc. ("OraVax").

         WHEREAS, Peptide Therapeutics Group plc ("Peptide"), Peach Acquisition
Corp. ("Peach") and OraVax, Inc. have entered into an Agreement and Plan of
Acquisition, dated November 10, 1998 (the "Merger Agreement"), whereby OraVax is
to be merged with and into Peach by way of a merger (the "Merger") with OraVax
as the surviving corporation;

         WHEREAS, Peptide has transferred all of the issued and outstanding
stock of Peach to Limited;

         WHEREAS, effective upon the effective time of the Merger (the
"Effective Time"), OraVax will become a wholly-owned subsidiary of Limited;

         NOW, THEREFORE, in consideration of the mutual agreements herein set
forth and for other good and valuable consideration the receipt of which is
hereby acknowledged, the parties hereby agree as follows:

                                   ARTICLE I
           COVENANTS, REPRESENTATIONS AND ACKNOWLEDGEMENTS OF LIMITED

         1.1 At the Effective Time and subject to satisfaction of the conditions
to effectiveness set forth in Article III hereof, Limited hereby covenants to
cause (i) OraVax to enter into each of the agreements attached hereto as Annexes
A - E (each a "New Agreement" and collectively, the "New Agreements") and (ii)
representatives of OraVax in the Partnerships to approve and cause to be
executed the agreements attached hereto as Annexes B and C.

         1.2 Limited covenants and agrees to appoint CT Corporation, 1633
Broadway, New York, New York as its agent for service of process prior to
[]* unless this Agreement has been terminated prior to such time.

         1.3 Limited agrees to use its best efforts to cause OraVax to maintain
all of its rights that are being acquired by PMC under the New Agreements until
the Effective Time. Under no circumstances shall Limited or any of its
affiliates authorize, permit or consent to any action by OraVax which could have
the effect of depriving PMC of any of the rights which it is acquiring under the
New Agreements. In the event that Peptide, Limited or OraVax cannot, at the
Effective Time, perform its obligations under any of the license agreements
attached hereto 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.

<PAGE>

as Annexes A - C due to any action or omission of Peptide, Limited, or OraVax
(or any of their respective Affiliates), such failure shall constitute a
material breach of this Agreement and any and all other agreements executed
between Limited or Peptide and PMC (or any of their respective Affiliates)
(including, without limitation, any agreement by which PMC (or any of its
Affiliates) purchase any of the ordinary shares or other equity interests in
Peptide).

         1.4 Limited hereby represents and warrants that:

              (a) Limited owns all of the issued and outstanding shares of Peach
         free and clear of any encumbrance and except for the shares of Peach
         owned by Limited, there are no shares of any class or series of capital
         stock, and no preferred stock, bonds, debentures, notes, debt
         instruments, evidences of indebtedness or other securities of any kind
         (including, without limitation, any stock options or stock appreciation
         rights), of Peach authorized, issued or outstanding. Peach has not
         issued any securities in violation of any preemptive or similar rights.

              (b) Limited is a corporation duly incorporated and validly
         existing and (to the extent applicable) in good standing under the laws
         of its jurisdiction of organization, with the corporate power to own,
         lease and operate its properties and to carry on its business as now
         conducted.

              (c) Limited has all necessary corporate power and authority to
         enter into this Agreement and to consummate the transactions
         contemplated hereby.

              (d) The execution, delivery and performance of this Agreement by
         Limited does not conflict with or contravene the articles or
         certificate of incorporation or by-laws, regulations or partnership
         agreement (or other comparable governing instruments with different
         names) of Limited, nor will the execution, delivery or performance of
         this Agreement conflict with or result in a breach of, or entitle any
         party thereto to terminate, any material agreement or instrument to
         which Limited is a party, or by which any of its assets or properties
         is bound.

              (e) This Agreement has been duly authorized, executed and
         delivered by Limited and constitutes a legal, valid and binding
         agreement of Limited, enforceable against Limited in accordance with
         its terms, except as enforceability may be limited by bankruptcy,
         insolvency, moratorium, reorganization or other similar laws affecting
         creditors' rights generally.

              (f) OraVax is validly existing as a corporation in good standing
         under the laws of Delaware, with corporate power to enter into each of
         the New Agreements and when executed, each of the New Agreements will
         constitute legal, valid and binding obligations of OraVax, enforceable
         against OraVax in accordance with their terms, subject to applicable
         bankruptcy insolvency, fraudulent conveyance, reorganization,
         moratorium and similar laws affecting creditors' rights and remedies
         generally, and subject, as to enforceability, to general principles of
         equity, including principles of commercial reasonableness, good faith
         and fair dealing (regardless of whether enforcement is sought in a
         proceeding at law or in equity).

                                       2

<PAGE>

              (g) The execution, delivery and performance of the New Agreements
         by OraVax will not result in any violation of any law, rule or
         regulation and will not result in the violation of the certificate of
         incorporation or bylaws of OraVax or any writ, judgment or decree to
         which OraVax is a party.

              (h) No authorization or approval or other action by, and no notice
         to or filing with, any governmental authority or regulatory body is
         required for the execution and delivery of any of the New Agreements
         and the performance by OraVax of the transactions contemplated by the
         New Agreements.

         1.5 Limited acknowledges that: (i) each of the New Agreements has been
negotiated at arms-length, (ii) during such negotiations Limited was represented
by counsel and was free from any undue influence or duress, (iii) the New
Agreements in the forms attached represent the terms and conditions agreed to by
the parties and that there are no other agreements or understandings with
respect to such agreements and such agreements accurately reflect all agreements
required to be reached in respect of the matters discussed therein.

                                   ARTICLE II
                  SPECIFIC PERFORMANCE; CONSENT TO JURISDICTION

         2.1 Limited agrees that, in view of the unique rights which are the
subject of and affected by this Agreement, in the event that Limited breaches
this Agreement, monetary damages could not be calculated and would not fairly
compensate PMC or be an adequate remedy to PMC for the damages resulting from
such breach. Accordingly, Limited agrees that if Limited breaches this
Agreement, PMC is entitled to specific performance requiring Limited to comply
with the terms of the New Agreements hereof as an alternative to any other
remedies available to PMC at PMC's sole discretion, PROVIDED, HOWEVER, that any
such election by PMC shall not limit PMC's right to incidental and/or
consequential damages, if any, caused by Limited's breach of this Agreement. In
any action successfully brought by PMC pursuant to this Section 2.1 for such
breach, Limited agrees to reimburse PMC for any costs or expenses incurred in
connection with such action, including, without limitation, expert witness fees
and reasonable attorneys fees. Limited further agrees and acknowledges that any
such action by PMC for injunctive relief may be brought in federal court for the
Southern District of New York or in the Supreme Court of New York, County of New
York, that there is jurisdiction over Limited in both the federal court for the
Southern District of New York, and the Supreme Court of New York, County of New
York and that Limited will not challenge the jurisdiction or venue of either of
those courts over Limited.

                                  ARTICLE III
                           CONDITIONS TO EFFECTIVENESS

         3.1 The obligations of the parties under Section 1.1 are subject to (i)
the execution and delivery of that certain First Amendment to Facility Agreement
dated of even date herewith between PMC and OraVax JVM, Inc. and (ii) the
execution and delivery of that certain Subscription Agreement dated of even date
herewith between PMC and Peptide and payment of the Subscription Price.

                                       3

<PAGE>

                                   ARTICLE IV
                                   TERMINATION

         4.1 This Agreement may be terminated at any time prior to the Effective
Time:

         (a) By mutual written consent of the parties hereto;

         (b) By PMC, by written notice to Limited:

              (i)  upon the public announcement of a tender offer or exchange
                   offer by any person other than PMC or an affiliate of PMC for
                   securities of OraVax;

              (ii) upon the occurrence of any event under the Merger Agreement
                   that would entitle Peptide to terminate the Merger Agreement
                   (irrespective of any waivers that may be given by Peptide to
                   OraVax under the Merger Agreement and irrespective of any
                   breach by Peptide of any representations, warranties,
                   covenants or other agreements contained in the Merger
                   Agreement);

              (iii) upon the public announcement of, or PMC otherwise becoming
                   aware of, the submission to OraVax by any person other than
                   PMC or an affiliate of PMC of an Acquisition Proposal (as
                   defined in the Merger Agreement); or

              (iv) if any of the representations and warranties in Article I are
                   not true and correct at the Effective Time or if the covenant
                   contained in Section 1.2 has not been performed by 
                   []*

         4.2 Limited shall promptly notify PMC of the occurrence, to its
knowledge, of any event referenced in Sections 4.1(b)(ii) above or the
submission of an Acquisition Proposal referenced in Section 4.1(b)(iii) above.

         4.3 This Agreement shall terminate automatically upon any termination
of the Merger Agreement.

         4.4 No termination of this Agreement shall relieve any party from
liability by reason of any breach by such party of any of its covenants or
representations contained herein occurring prior to the termination of this
Agreement.

                                   ARTICLE V
                                  MISCELLANEOUS

         5.1 PUBLICITY. PMC and Peptide shall cooperate in the preparation of a
mutually-agreeable press release and other publicity disclosing the existence of
this Agreement and their business relationship. Except for the information
disclosed in such press release or publicity, neither PMC nor Peptide shall
disclose the existence or any terms of this Agreement 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       4


<PAGE>

without the prior written consent of the other party (which consent shall not be
unreasonably withheld), except for such limited disclosure as may be reasonably
necessary to either party's bankers, investors, attorneys or other professional
advisors, or in connection with a merger or acquisition, or as may be required
by law in the offering of securities or in securities or regulatory filings or
otherwise, PROVIDED, THAT, the party disclosing such information shall provide a
copy of the proposed disclosure to the other party before it is disclosed and
afford the other party a reasonable amount of time to provide comments on such
proposed disclosure.

         5.2 All notices and other communications required or permitted
hereunder shall be in writing and shall be deemed given when so delivered in
person, by overnight courier, by facsimile transmission (with receipt confirmed
by telephone or by automatic transmission report) or two business days after
being sent by registered or certified mail (postage prepaid, return receipt
requested), as follows:

                  (a)      If to Limited, to:

                           Peptide Therapeutics Limited
                           321 Cambridge Science Park
                           Milton Road
                           Cambridge CB4 4WG
                           England
                           Attn:    Chief Executive
                           Telephone:       01223 423333
                           Facsimile:       01223 423341

                           with a copy to:

                           Palmer & Dodge LLP
                           One Beacon Street
                           Boston, Massachusetts  02108
                           Attn:    Michael Lytton, Esq.
                           Telephone:       (617) 573-0100
                           Facsimile:       (617) 227-4420

                  (b)      If to PMC, to:

                           Pasteur Merieux Serums & Vaccins S.A.
                           58, avenue Leclerc
                           69007 Lyon, France
                           Attn:    Senior Vice President, Corporate and Legal 
                                    Affairs, and General Counsel
                           Telephone:       011 33 4 37 37 77 84
                           Facsimile:       011 33 4 37 37 70 61

                           with a copy to:

                           Akin, Gump, Strauss, Hauer & Feld, L.L.P.

                                       5

<PAGE>

                           590 Madison Avenue
                           New York, New York  10022
                           Attn:    L. Kevin O'Mara, Jr.
                           Telephone:       (212) 872-1000
                           Facsimile:       (212) 872-1002

Any party may by notice given in accordance with this Section 5.2 to the other
parties designate another address or person for receipt of notices hereunder.

         5.3 This Agreement shall be construed in accordance with and governed
by the internal laws of the State of New York, without regard for its conflicts
of laws principles.

         5.4 This Agreement may be amended, modified or supplemented only by
written agreement of the parties hereto.

         5.5 This Agreement and all of the provisions hereof shall be binding
upon and inure to the benefit of the parties hereto and their respective
successors and permitted assigns. This Agreement is not assignable without the
prior written consent of the other party hereto.

         5.6 This Agreement may be executed in two or more counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         5.7 This Agreement contains the entire agreement among the parties in
respect of the subject matter contained herein, and supersedes all prior
agreements, written or oral, with respect thereto.

                                       6

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed as of the day and year first written above.



                                           PEPTIDE THERAPEUTICS LIMITED



                                           By: /s/ Nicolas A. Higgins
                                               ---------------------------------
                                               Name:  Nicolas A. Higgins
                                               Title: Commercial Director



                                           PASTEUR MERIEUX SERUMS & VACCINS S.A.

                                           By: /s/ Paul Kirkconnell
                                               ---------------------------------
                                               Name:  Paul Kirkconnell
                                               Title: Corporate Vice President


<PAGE>

                                                                      ANNEX A TO
                                                                   EXHIBIT 10.10


                                LICENSE AGREEMENT

         THIS LICENSE AGREEMENT (the "Agreement") is effective as of ________ 
____________, 1999, between OraVax, Inc. ("OraVax"), a corporation organized 
and existing under the laws of the State of Delaware, as Licensor 
("Licensor") and Pasteur Merieux Serums & Vaccins S.A., a corporation 
organized under the laws of France, as Licensee ("Licensee").

                              W I T N E S S E T H:

         WHEREAS, Licensor owns or possesses certain proprietary rights and
know-how relating to the creation of []*

         WHEREAS, Licensee desires to obtain from Licensor, and Licensor desires
to grant to Licensee, a license under Licensor's proprietary rights and know-how
to research, develop, manufacture, market, sell and distribute Licensed Products
(as defined below);

         NOW THEREFORE, in consideration of the covenants, conditions, and
undertakings hereinafter set forth, it is agreed by and among the parties as
follows:

                                    ARTICLE 1

                                   DEFINITIONS

         "Affiliate" shall mean, with respect to any Person, (i) any other
Person of which securities or other ownership interests representing fifty
percent (50%) or more of the voting interests of such other Person are, at the
time such determination is made, owned, Controlled or held directly or
indirectly, by such Person, or (ii) any other Person which, at the time such
determination is being made, is Controlling, Controlled by or under common
Control with, such Person. For the purposes hereof, "Control," whether used as a
noun or verb, refers to the possession directly or indirectly, of the power to
direct, or cause the direction of, the management or policies of a Person,
whether through the ownership of voting securities, by contract or otherwise.

         "Agency" shall mean any supranational, national, regional, state or
local government regulatory authority in the Territory responsible for granting
approvals for the manufacture or sale of Licensed Products.

         "Development Costs" shall mean the costs incurred by Licensor in
connection with the performance of Development Work pursuant to any Research and
Development Program.

         "Dengue License" means the license agreement by and between Licensee
and OraVax effective as of October 1, 1998.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.
<PAGE>

         "Dengue Vaccine" shall mean a vaccine either therapeutically or
prophylactically active against dengue viruses that makes use of, or is based
upon, the Technology licensed to the Licensee pursuant to the Dengue License.

         "Development Work" shall mean the research and development activities
to be performed by Licensor pursuant to an agreed-upon Research and Development
Program.

         "Fields of Use" shall mean the JEV Field and the TBE Field, and "Field
of Use" shall mean one of them.

         "Improvements" shall mean any improvements to the Licensed Product
which are first conceived, discovered or actually reduced to practice during and
after the performance of the Development Work under an agreed-upon Research and
Development Program.

         "Intellectual Property" shall mean, collectively, Inventions and
Improvements.

         "Inventions" shall mean any inventions, ideas, discoveries which are
first conceived, discovered or actually reduced to practice before, during and
after the performance of the Development Work under an agreed-upon Research and
Development Program and are related to a Licensed Product.

         "JEV Field" means shall mean the development and commercialization of
JEV Vaccines.

         "JEV Vaccine" shall mean a vaccine either therapeutically or
prophylactically active against Japanese encephalitis viruses that makes use of
Licensor's ChimeriVax technology for the creation of []*

         "Legal Requirements" shall mean all laws, statutes, ordinances, codes,
rules, regulations, published standards, permits, judgments, decrees, writs,
injunctions, rulings, orders and other requirements of all Public Authorities.

         "Licensed Know-How" shall mean any biological materials, and any
research and development information, inventions, know-how, pre-clinical,
clinical and other technical data, in each case which are not generally known or
available, which are owned, licensed or otherwise held by Licensor with the
right to license or sublicense the same to Licensee as of the date hereof or at
any time hereafter and which are necessary or useful for the making, using or
selling of Licensed Products as provided in this Agreement.

         "Licensed Product(s)" shall mean any product within the Fields of Use.

         "Major Country" shall mean France, Germany, Italy, the United Kingdom
or the United States.

         "Net Sales" shall mean the gross invoice price to Third Parties of any
Licensed Product, less: (i) retroactive price reductions and rebates customary
to the trade or required by law, credits for returns and allowances, all to the
extent actually allowed, (ii) sales or other excise taxes or duties imposed upon
and paid by Licensee, or any of its Affiliates or Permitted 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       2

<PAGE>

Sublicensees with respect to such sales, and (iii) transportation charges and
insurance for transportation to the extent separately invoiced or separately
reported on the invoice and paid by the Third Party. Notwithstanding the
foregoing, Net Sales shall not include sales between or among Affiliates for
resale by an Affiliate.

         "Patent Rights" shall mean:

              (a) all patents and patent applications owned or controlled by
         Licensor, or licensed to Licensor with rights to grant sublicenses
         thereunder, anywhere in the world as of the date hereof or at any time
         hereafter relating to a Field of Use and which are (i) listed on
         Schedule A, (ii) issued, assigned or licensed to Licensor at any time
         hereafter and that are necessary or useful for the making, using or
         selling of Licensed Products as provided in this Agreement, or (iii)
         based on any Inventions that are necessary or useful for the making,
         using or selling of Licensed Products as provided in this Agreement,
         and

              (b) any improvement patents, reissues, confirmations, renewals,
         extensions, counterparts, divisions, continuations,
         continuations-in-part or patent-of-addition issued, assigned or
         licensed to Licensor of or relating to the patents or patent
         applications described in clause (a) hereof.

         "Permitted Sublicensee" shall mean any Affiliate of Licensee, and any
other Person approved in writing by Licensor prior to the granting of the
applicable sublicense.

         "Person" shall mean any natural person, corporation, firm, business
trust, joint venture, association, organization, company, partnership or other
business entity, or any government, or any agency or political subdivision
thereof.

         "Public Authority" shall mean any supranational, national, regional,
state or local government, court, governmental agency, authority, board, bureau,
instrumentality or regulatory body.

         "Research and Development Program" shall have the meaning set forth in
Section 4.1(a).

         "TBE Field" shall mean the development and commercialization of TBE
Vaccines.

         "TBE Vaccines" shall mean a vaccine either therapeutically or
prophylactically active against tick-borne encephalitis viruses that makes use
of Licensor's ChimeriVax technology for the creation of []*

         "Technology" shall mean the Patent Rights and Licensed Know-How.

         "Territory" shall mean all countries of the world.

         "Third Party" shall mean any Person which is not a party or an
Affiliate of a party hereto.

         "Valid Claim" shall mean a claim of an issued and unexpired patent
included within the Patent Rights that has not been held unenforceable or
invalid by a court or other governmental 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       3

<PAGE>

agency of competent jurisdiction in a final adjudication from which no appeal
can be taken and that has not been specifically admitted by the Licensor to be
invalid or unenforceable through statements or actions that legally bind the
Licensor to such admission.

                                   ARTICLE 2

                                 GRANT OF RIGHTS

         2.1 LICENSE. Subject to the terms and conditions of this Agreement,
Licensor hereby grants to Licensee a right and license, with the right to grant
sublicenses, under the Technology to research, have researched, make, have made,
use, sell, distribute, import and export Licensed Products in the Territory,
which right and license shall be exclusive even as to Licensor; provided that
Licensor shall retain the right to research, have researched, make, have made
and use Licensed Products for all purposes unrelated to the commercialization of
Licensed Products.

         2.2 EXCLUSIVITY. In order to assure Licensee of the exclusive rights
under the Technology to commercialize Licensed Products granted in Section 2.1
hereof, Licensor shall not itself sell, distribute, import or export Licensed
Products in the Territory or grant to a Third Party any rights or licenses to
research, have researched, make, have made, use, sell, distribute, import or
export Licensed Products in the Territory, except as provided by this Agreement
and for so long as the rights and licenses granted in Section 2.1 remain in
force pursuant to this Agreement.

         2.3 SUBLICENSES.

              (a) The rights granted under Section 2.1 may be sublicensed by
         Licensee (or any Permitted Sublicensee) to any Permitted Sublicensee.
         In the event that Licensee (or any Permitted Sublicensee) desires to
         sublicense any rights granted under Section 2.1 to any Third Party,
         Licensee shall furnish to Licensor for its approval, which shall not be
         unreasonably withheld or delayed, a prior draft of the proposed
         sublicense agreement, which shall be on substantially the same terms
         (other than Section 3.3) as this Agreement and (y) provide Licensor
         with an executed copy of any such approved sublicense agreement. In the
         event that Licensee (or any Permitted Sublicensee) desires to amend any
         sublicense agreement theretofore approved by Licensor, such amendment
         shall similarly require Licensor's prior approval, which similarly
         shall not be unreasonably withheld or delayed.

              (b) Each sublicense agreement concluded by Licensee hereunder
         shall include a requirement that the Permitted Sublicensee maintain
         records and permit inspection on terms similar to those set forth in
         Section 10.4 of this Agreement. At Licensor's request and subject to
         the terms of the applicable sublicense agreement, Licensee shall
         arrange for an independent public accountant selected by Licensor to
         inspect the records of its Permitted Sublicensee(s) for the purpose of
         verifying payments due to Licensor and shall cause such accountant to
         report the results thereof to Licensor.

                                       4

<PAGE>

              (c) Each sublicense agreement concluded by Licensee hereunder will
         include indemnification provisions similar to those set forth in
         Section 8.3 hereof naming Licensee and Licensor (and their respective
         officers, directors, employees and agents) as indemnified parties.

              (d) All sublicenses granted hereunder shall terminate upon
         termination of this Agreement; provided that upon expiration of the
         Term pursuant to Section 5.1 hereof (prior to any termination
         hereunder), Licensee (or the applicable Permitted Sublicensee) shall
         have a fully paid-up, royalty-free, non-cancelable license, subject (in
         the case of Licensee's Permitted Sublicensees) to the terms of the
         applicable sublicense and the payment by Licensee of amounts accrued
         prior to such expiration.

         2.4 DISCLOSURE OF TECHNOLOGY. Promptly following the execution of this
Agreement, and periodically thereafter as such information becomes available to
Licensor, Licensor shall provide to Licensee copies of all information and
materials in tangible form related to the Technology that are reasonably
necessary to or useful in the researching, making, using, selling, distributing,
importing or exporting of Licensed Products. Without limiting the generality of
the foregoing, if at any time Licensee elects to manufacture a Licensed Product,
Licensor shall, upon notice from Licensee, transfer Licensed Know-How relating
to manufacturing of the Licensed Product to Licensee, together with seed stock
or other biological materials within the definition of Licensed Know-How.

                                   ARTICLE 3

                                  COMPENSATION

         3.1 COMPENSATION FOR PAST RESEARCH AND DEVELOPMENT EXPENSES RELATING 
TO LICENSOR'S TBE VACCINE KNOW-HOW. Subject to the following sentence, 
Licensee shall pay to Licensor compensation of []* in respect of Licensor's 
past research and development expenses relating to TBE Vaccine (the 
"Reimbursement Payment"). In the event that the Licensee fails to make the 
Reimbursement Payment when due, the license granted hereunder in respect of 
TBE Vaccine shall terminate, but the license granted with respect to JEV 
Vaccine shall continue in full force and effect. Any payment by Licensee 
hereunder shall be made by Licensee by the later to occur of []*

          3.2 MILESTONE FEES. Licensee shall pay to Licensor the amounts 
specified below within []* following the accomplishment of the 
corresponding events specified below (each, a "Milestone"):

              (i) []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       5

<PAGE>

              (ii) []*


              (iii) []*


              (iv) []*


              (v) []*


              (vi) []*


              (vii) []*


              (viii) []*


              (ix) []*


              (x) []*

         The foregoing amounts shall be paid by Licensee (on behalf of itself,
its Affiliates and Permitted Sublicensees) only once.

         3.3 ROYALTIES.

         (A) ROYALTY RATES.

                   (i) Licensee shall pay Licensor a royalty of []* (the
              "Patent Royalty") on quarterly Net Sales of Licensed Product by
              Licensee, its Affiliates


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       6

<PAGE>

              and Permitted Sublicensees in countries where at least one Valid
              Claim exists during all periods of such existence. Such royalty
              shall be payable on a country-by-country basis until the
              expiration of the last remaining Valid Claim in any such country.

                   (ii) In the case of countries in which the Patent Rights
              consist solely of patent applications, Licensee shall pay Licensor
              the Patent Royalty on quarterly Net Sales of Licensed Product by
              Licensee, its Affiliates and Permitted Sublicensees in such
              countries until the first to occur of []* Upon the []* Licensee 
              shall pay Licensor a royalty of []* (the "Know-How Royalty") on 
              quarterly Net Sales of Licensed Product by Licensee, its 
              Affiliates and Permitted Sublicensees in such country for 
              []* provided, however, that upon issuance of a Valid Claim in 
              such country at any time thereafter, Licensee shall pay 
              Licensor in accordance with subsection (i) above.

                   (iii) Licensee shall pay Licensor the Know-How Royalty on
              quarterly Net Sales of Licensed Product by Licensee, its
              Affiliates and Permitted Sublicensees, in countries where no
              Patent Rights exist and in countries where the only existing
              Patent Rights have, for a period of []* been patent applications, 
              for a period of []* PROVIDED, HOWEVER, that if at any time 
              thereafter Patent Rights come to exist in any such country, 
              Licensee shall pay royalties to Licensor in accordance with 
              subsection (i) or (ii) above as appropriate. In no event shall 
              the Know-How Royalty be payable in respect of any Net Sales 
              upon which the Patent Royalty is payable.

              (B) REDUCTION FOR THIRD PARTY ROYALTIES. In the event that
         Licensee, its Affiliate(s) or Permitted Sublicensee(s), in its
         reasonable judgment, determines it to be necessary or desirable to
         license in Third Party patents or technology relating to the Licensed
         Product and is required to pay royalties to one or more Third Parties
         in respect of such patents or technology (that in the absence of such
         royalty payments would be infringed by the researching, making, using,
         selling, distributing, importing or exporting of the applicable
         Licensed Product) in order to enable Licensee, such Affiliate or such
         Permitted Sublicensee to realize Net Sales, then the royalties
         otherwise payable to Licensor in respect of such Net Sales shall be
         reduced by []* the royalties paid to such Third Parties;
         provided, however, that in no event shall such reduction exceed
         []* of the royalties on such Net Sales otherwise due to Licensor.

              (C) RIGHT TO CURE CERTAIN THIRD PARTY OBLIGATIONS; OFFSET.
         Licensee acknowledges that the patent applications set forth on
         Schedule A hereto are co-owned 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       7

<PAGE>

              by Licensor with St. Louis University, in accordance with the
              agreement attached hereto as Schedule B. In the event that
              Licensor defaults on its obligations under the agreement attached
              hereto as Schedule B, Licensor shall promptly notify Licensee of
              such default and shall, at Licensee's request, cooperate with
              Licensee to enable Licensee to cure such breach on behalf of
              Licensor. Licensee shall be entitled to deduct from the royalties
              otherwise payable to Licensor in respect of Net Sales hereunder
              all royalties and other expenses incurred under this Section
              3.3(c) that are reasonably necessary to ensure that Licensee's
              rights under this Agreement are not compromised by such default.

         3.4 FUNDING OF RESEARCH AND DEVELOPMENT PROGRAM. The parties agree that
Licensee shall be responsible for funding all research and development costs
with respect to the Licensed Products. With respect to JEV Vaccine, Licensee
shall reimburse Licensor for the Development Costs, including the development
program costs for the JEV Vaccine development program to be carried out by
Licensor through the completion of a Phase I clinical study in adults, in
accordance with the Dengue License. Such JEV Vaccine development program shall
otherwise be conducted and managed consistent with Article 4 hereof. In the
event that Licensee wishes to continue to fund further Development Work, such
further funding shall be made in accordance with the provisions of Article 4
hereof.

         3.5 SINGLE ROYALTY; NON-ROYALTY SALES. It is understood that in no
event shall more than one royalty be payable under Section 3.3 with respect to a
particular unit of Licensed Product. No royalty shall be payable under this
Article 3 with respect to sales of Licensed Products among Licensee, its
Affiliates, Permitted Sublicensees and their Affiliates (provided that such
sales are for the purpose of facilitating resales to Third Parties), but a
royalty shall be due upon the subsequent sale of the Licensed Product to a Third
Party. No royalty shall be payable for (i) Licensed Product used in clinical
trials, or (ii) Licensed Product used by Licensee, its Affiliates or Permitted
Sublicensees for research, or (iii) customary quantities of Licensed Product
distributed as free samples.

                                   ARTICLE 4

                            RESEARCH AND DEVELOPMENT

         4.1 RESEARCH AND DEVELOPMENT PROGRAM.

              (A) GENERAL. In the event that Licensee so requests, and subject
         to agreement by the parties hereto on the research and development
         program to be conducted in respect of any Licensed Product (each, a
         "Research and Development Program"), Licensor agrees to perform or have
         performed for the Licensee the Development Work set forth in any such
         Research and Development Program, and Licensee hereby agrees to fund
         the Research and Development Program in accordance with the terms and
         conditions set forth below. Such research and development programs
         shall be generally consistent with the programs established by the
         parties for JEV Vaccines and Dengue Vaccines except as may be modified
         to account for any differences in the technology of such Licensed
         Product. Without limiting the generality of the foregoing, the parties
         agree that upon the reasonable request of Licensee (subject to Section
         9.1 hereof), Licensor shall prepare 

                                       8

<PAGE>

         clinical constructs in respect of TBE Vaccine, provided that the
         parties can agree on the budget therefor (including the number of and
         costs of the FTE's assigned to the project).

              (B) SUBCONTRACTING. Licensor may subcontract any or all of its
         obligations under this Article 4, subject to obtaining the prior
         written consent of Licensee, which consent shall not be unreasonably
         withheld. In the event that Licensor desires to subcontract any
         material part of its obligations under this Article 4 to any Third
         Party, Licensor shall (x) furnish to Licensee for its approval a prior
         draft of the proposed subcontract agreement, which shall be in form and
         substance satisfactory to Licensee, (y) provide Licensee with an
         executed copy of any such approved subcontract agreement, and (z) keep
         Licensee informed of the status of any such subcontracting
         arrangements. In the event that Licensor desires to amend any
         subcontract agreement theretofore approved by Licensee, such amendment
         shall similarly require Licensee's prior approval. No such subcontract
         shall relieve Licensor of its obligations under this Agreement.

              (C) RESEARCH AND DEVELOPMENT COMMITTEE, PRINCIPAL INVESTIGATOR.
         The Development Work (if any) shall be performed under the supervision
         and direction of the Principal Investigator who shall be an employee of
         Licensor and shall be chosen by the Research and Development Committee.
         The Research and Development Committee shall consist of three
         individuals nominated by Licensor and three individuals nominated by
         Licensee. The Research and Development Committee shall review the
         progress of the Development Work and will approve or reject material
         changes to the Development Work plan. The Research and Development
         Committee can change its number of members (maintaining equal
         representation of both Licensee and Licensor) and its membership upon
         the decision of a majority of its members. The Research and Development
         Committee shall survive the term of the Research and Development
         Program in an advisory role until a time mutually agreeable to Licensee
         and Licensor or, in the absence of mutual agreement, until []*
         following product licensure of a Licensed Product in a Major Country.
         The members of the Research and Development Committee shall be senior
         executives from the various research and development disciplines of
         Licensor and Licensee. The initial members of the Research and
         Development Committee are indicated in Appendix A hereto.

              (D) REPLACEMENT OF PRINCIPAL INVESTIGATOR. In the event that the
         Principal Investigator is unwilling or unable to perform his or her
         duties hereunder, Licensor shall promptly appoint a successor mutually
         agreeable to the parties.

              (E) REPORTS. The Principal Investigator shall provide written
         progress reports, summarizing in reasonable detail the current status
         and progress of each Research and Development Program (i) within thirty
         (30) days after the end of each calendar quarter and (ii) as soon as
         practicable whenever, in the Principal Investigator's judgment, an
         Invention has been created or reduced to practice.

              (F) VISITATION. Duly authorized representatives of Licensee shall
         have the right at reasonable times and upon reasonable notice to visit
         the facilities where any Development Work is being performed in order
         to monitor progress of the Development Work.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       9

<PAGE>

         4.2 FUNDING.

              (A) GENERAL. Licensor shall provide (or cause to be provided) to
         Licensee, prior to the beginning of each quarter in which Development
         Work is to be performed in accordance with a Research and Development
         Plan, an invoice setting forth the projected Development Costs to be
         incurred for such quarter in accordance with any Research and
         Development Program. Licensee shall pay such invoice within []* of  
         receipt thereof to the extent that such Development Costs are included 
         in the Research and Development Plan (as modified from time to time 
         by the Research and Development Committee). Licensor hereby covenants 
         and agrees that any funding provided to Licensor under this Section 4.2
         shall be used as contemplated by the applicable Research and 
         Development Program. Services provided by Licensor at Licensee's
         request that are outside the scope of a Research and Development
         Program shall be separately invoiced by Licensor and separately funded
         by Licensee on the basis for determining costs set forth in Appendix A
         hereto.

              (B) RECONCILIATION. Within []* after the end of each quarter in 
         which Development Work is performed in accordance with a Research and 
         Development Plan, Licensor shall provide (or cause to be provided) to 
         Licensee a statement reconciling the projected Development Costs 
         previously paid by Licensee for such quarter against the actual
         Development Costs incurred by Licensor for such quarter. In the event
         that such reconciliation demonstrates that such previous payment
         exceeded such actual Development Costs, Licensee shall be entitled to
         recoup the excess from Licensor. In the event that such reconciliation
         demonstrates that such actual Development Costs exceeded such previous
         payment, Licensor shall be entitled to reimbursement of the excess from
         Licensee. At the option of the party to whom any such adjustment is
         owed, such excess shall be paid to such party by the other party within
         []* after such statement is provided or an appropriate adjustment 
         shall be made to the next invoice provided to Licensee setting forth
         projected Development Costs (in which case such adjustment shall be
         subtracted from or added to actual Development Costs, as 
         appropriate, for purposes of the subsequent reconciliation relating 
         to the quarter to which such invoice relates).

              (C) COST OF COMPONENTS. Any component that, by mutual agreement of
         Licensee and Licensor, is supplied by Licensee to Licensor in
         connection with the Development Work to performed hereunder shall be
         supplied to Licensor at no cost.

         4.3 SUBLICENSE AND LICENSE.

         (a) In the event that, and for so long as, any Research and Development
Program is on-going, Licensee hereby grants to Licensor a fully paid,
non-exclusive, royalty-free sublicense, with the right to grant sublicenses
(subject to Section 4.1(b) hereof), under the rights and licenses granted
pursuant to Section 2.1 above to research, develop, make and have made the
applicable Licensed Product in the Territory solely for the purposes of
performing the Development Work pursuant to the applicable Research and
Development Program.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       10
<PAGE>

         (b) In the event that, and for so long as, any Research and Development
Program is on-going, Licensee hereby grants to Licensor a fully paid,
non-exclusive, royalty-free license, with the right to grant sublicenses
(subject to Section 4.1(b) hereof), under the Intellectual Property owned by
Licensee as specified in Sections 4.4(d) and 4.4(e) hereof to research, develop,
make and have made the applicable Licensed Products in the Territory solely for
the purposes of performing the Development Work pursuant to the applicable
Research and Development Program.

4.4      OWNERSHIP OF INVENTIONS AND IMPROVEMENTS.

              (a) All Intellectual Property developed solely by Licensor
         pursuant to a Research and Development Program shall be owned solely by
         Licensor, and such Intellectual Property shall be deemed to be included
         in the Technology.

              (b) All Intellectual Property developed jointly by Licensor and
         Licensee pursuant to a Research and Development Program and solely
         relating to a Licensed Product shall be owned jointly by the parties
         and Licensee shall have an exclusive right and license to Licensor's
         interest in such Intellectual Property pursuant to Section 2.1 above.

              (c) All Intellectual Property developed jointly by Licensor and
         Licensee pursuant to the Research and Development Program and not
         solely relating to a Licensed Product shall be owned jointly by the
         parties and both parties shall have the right to use and exploit such
         Intellectual Property freely without accounting to one another for such
         use and exploitation.

              (d) All Intellectual Property developed solely by Licensee
         pursuant to a Research and Development Program and solely relating to a
         Licensed Product shall be owned solely by Licensee.

              (e) All Intellectual Property developed solely by Licensee and
         which is not solely related to a Licensed Product shall be owned by
         Licensee. The parties shall, at Licensor's request, enter into good
         faith negotiations for a grant of licenses to such Intellectual
         Property from Licensee to Licensor for use outside of the Fields of
         Use.

              (f) Licensor agrees to include provisions assuring Licensee's
         rights under this Section 4.4 in every sublicense granted pursuant to
         Section 4.3 above.

              4.5 DISPUTE RESOLUTION.

              (a) The parties agree to use their best efforts to resolve
         amicably any deadlock between the parties or their respective
         representatives, with respect to any scientific matter and will not
         take any action inconsistent therewith. The resolution of any deadlock
         pursuant to this Section 4.5 shall be binding on the parties for all
         purposes.

              (b) In the event that the parties or their respective
         representatives are deadlocked concerning any scientific matter, the
         parties shall thereupon consult with each other in good faith on a
         regular basis (including at least one meeting between the Chief

                                       11

<PAGE>

         Scientific Officer of Licensor and the Chief Scientific Officer of
         Licensee for their consideration and resolution, and if no decision is
         then reached, at least one meeting between the Chief Executive Officer
         of Licensor and the Chief Executive Officer of Licensee) to attempt to
         resolve such matters as promptly as practicable and each party hereby
         agrees to use its best efforts to schedule such meetings within sixty
         (60) days after the occurrence of the deadlock.

              (c) In the event that, following the aforementioned consultations,
         the parties remain deadlocked regarding any scientific matter, such
         deadlock shall be referred, at the election of either party and by
         notice in writing to the other party, to a panel of scientific
         mediators as provided in this paragraph (c) ("Scientific Mediation").
         In any Scientific Mediation, there shall be three scientific experts in
         the pharmaceuticals area (without regard to nationality) who shall act
         as the mediators (the "Scientific Mediators"). The party requesting
         Scientific Mediation shall appoint one individual to serve as one of
         the Scientific Mediators, and shall notify the other party of such
         appointment in the aforementioned notice. Within fifteen (15) days
         after receipt of such notice, the other party shall appoint one
         individual to serve as a Scientific Mediator, but if the other party
         shall fail to make such appointment within such period, such party may
         request the Swedish Arbitration Committee of the ICC to make such
         appointment. The two Scientific Mediators shall, within fifteen (15)
         days of the appointment of the second Scientific Mediator appoint a
         third individual to serve as a Scientific Mediator and chairperson of
         the mediation board, but if the two Scientific Mediators shall fail to
         make such appointment within such period, then such party or the other
         party may request the Swedish Arbitration Committee of the ICC to make
         such appointment. No Confidential Information shall be disclosed to
         such Scientific Mediators unless and until each such Scientific
         Mediator has entered into a confidentiality agreement, in form and
         substance satisfactory to both parties. The Scientific Mediators shall
         be advised of the positions taken by each of the parties to such
         mediation and shall work with them in an effort to resolve the
         scientific deadlock within sixty (60) days after the appointment of the
         third Scientific Mediator. If the scientific deadlock is not resolved
         within such period, there shall be no further Scientific Mediation, but
         the Chief Executive Officer of Licensor and the Chief Executive Officer
         of Licensee shall consult one more time in an effort to resolve the
         deadlock.

                                   ARTICLE 5

                              TERM AND TERMINATION

         5.1 TERM. This Agreement shall become effective as of the date 
hereof and, subject to the other provisions of this Article 5, shall continue 
in full force and effect on a country-by-country basis until the later of []* 
(the "Term"). Upon the expiration of the Term on a country-by-country basis, 
Licensee will have a fully paid, royalty-free, freely sublicensable license 
to make, have made, use, sell, distribute, import and export Licensed 
Products in each such country, and Licensee 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       12

<PAGE>

shall have no further payment obligation to Licensor, other than for payments
that accrue prior to such expiration, for milestone payments that may accrue
after such expiration and for Development Costs that may be incurred after such
expiration.

         5.2 TERMINATION FOR BREACH. In the event of a material breach of this
Agreement (including the breach of a representation or warranty), which breach
is not cured within sixty (60) days after written notice is given by the
non-breaching party to the breaching party specifying the breach, the
non-breaching party, in addition to any other remedy which it may have, shall be
entitled to terminate this Agreement.

         5.3 OPTIONAL TERMINATION BY LICENSEE. Licensee may terminate this 
Agreement at any time by giving Licensor at least []* prior written notice.

         5.4 TERMINATION STANDSTILL. Notwithstanding anything to the contrary
contained herein, Licensee may not terminate this Agreement for any reason
before the earlier of []*

         5.5 RIGHTS ON TERMINATION.

              (a) In the event that this Agreement is terminated pursuant to
         Section 5.2 due to a material breach by Licensor, (i) the rights and
         licenses granted to Licensee in Section 2.1 hereof shall remain in
         effect, subject to Licensee's payment of []* of the royalties and []*
         of the milestone payments that that would otherwise accrue after such
         termination, (ii) the rights and licenses granted to Licensor in
         Section 4.3 shall terminate, (iii) subject to Article 7 hereof, any
         Confidential Information provided to Licensor in tangible form shall be
         promptly returned to Licensee or destroyed, at Licensee's option and
         (iv) Licensee shall have the rights set forth in Section 8.3 in respect
         of such breach.

              (b) In the event that this Agreement is terminated pursuant to
         Section 5.2 due to a material breach by Licensee, (i) all licenses
         granted hereunder, except the license granted to Licensor pursuant to
         Section 4.3(b), shall terminate, (ii) the license granted to Licensor
         pursuant to Section 4.3(b) shall be []* (iii) subject to Article 7 
         hereof, any Confidential Information and Licensed Know-How provided 
         to Licensee in tangible form shall be promptly returned to Licensor 
         or destroyed, at Licensor's option, and (iv) Licensor shall have the
         rights set forth in Section 8.3 in respect of such breach.

              (c) In the event that this Agreement is terminated pursuant to
         Section 5.3 at Licensee's option, (i) all licenses granted hereunder,
         except the license granted to Licensor pursuant to Section 4.3(b),
         shall terminate, (ii) the license granted to Licensor pursuant to
         Section 4.3(b) shall be []* (iii) subject to Article 7 hereof, any 
         Confidential Information and Licensed Know-How provided to Licensee in 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       13


<PAGE>

         tangible form shall be promptly returned to Licensor or destroyed, at
         Licensor's option, and (iv) Licensor and Licensee shall negotiate in
         good faith a percentage royalty to be paid by Licensor to Licensee,
         based upon the commercialization of Licensed Products subsequently
         undertaken by Licensor, that compensates Licensee for Licensor's
         exploitation of Intellectual Property developed during the course of a
         Research and Development Program using Licensee's funding at a level
         commensurate with the level of royalties Licensor pays to Third Parties
         in arm's-length transactions for licenses of intellectual property with
         similar commercial value.

              (d) In the event that a Research and Development Program is
         terminated by Licensee prior to the completion of its term for any
         reason, Licensee shall, in addition to any other payments due
         hereunder, make a payment equal to the []* Also in the event of such 
         termination, Licensor shall, and shall cause its employees, agents and
         subcontractors (including, without limitation, the Principal 
         Investigator) performing any Development Work to, wind up as 
         expeditiously as possible all Development Work that is in progress 
         at the date of such termination. Following such termination and 
         winding up, Licensor shall submit to Licensee a final invoice setting
         forth []*

              (e) In the event Licensee terminates this Agreement, all rights to
         Intellectual Property owned jointly pursuant to Section 4.4(c) shall
         remain the property of both Licensor and Licensee with divided control
         and the parties shall enter into good faith negotiations for the grant
         of an exclusive right and license to Licensee's interest in such
         Intellectual Property from Licensee to Licensor. In the event of
         Licensee's termination of this Agreement, the parties shall also enter
         into good faith negotiations for the grant of a license to Intellectual
         Property owned by Licensee pursuant to Section 4.4(d) from Licensee to
         Licensor.

              (f) Articles 7 and 11, and Sections 2.3, 5.1, 5.4, 5.5, 5.6, 8.3,
         10.3 and 10.4, shall survive the expiration and any termination of this
         Agreement. Except as otherwise provided in this Section 5.5(f), all
         rights and obligations of the parties under this Agreement shall
         terminate upon the expiration or termination of this Agreement.

              (g) Termination of this Agreement for any reason shall not release
         either party hereto from any liability which at the time of such
         termination has already accrued to the other party.

         5.6 In the event that Licensee terminates this Agreement for any
reason, and Licensee decides to continue the development of a Japanese
encephalitis vaccine or a tick-borne encephalitis vaccine other than a Licensed
Product, Licensee shall in good faith, but with no 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       14

<PAGE>

legal obligation, consider maintaining a collaborative relationship with
Licensor relating to such development.

         5.7 Subject to applicable law to the contrary, Licensee or Licensor may
terminate this Agreement upon written notice to the other party if the other
party makes a general assignment for the benefit of creditors, is the subject of
proceedings in voluntary or involuntary bankruptcy or has a receiver or trustee
appointed for substantially all of its property; provided that in the case of an
involuntary bankruptcy proceeding such right to terminate shall only become
effective if the other party consents thereto or such proceeding is not
dismissed within sixty (60) days after the filing thereof. Each of the parties
hereto acknowledges and agrees, subject to applicable law to the contrary, that
this Agreement (i) constitutes a license of Intellectual Property (as such term
is defined in the United States Bankruptcy Code, as amended (the "Code")), and
(ii) is an executory contract, with significant obligations to be performed by
each party hereto. The parties agree that Licensee may fully exercise all of its
rights and elections under the Code, if any, including, without limitation,
those set forth in Section 365(n) of the Code. The parties further agree that,
in the event that Licensee retains its rights as a licensee under the Code
pursuant to such an exercise, Licensee shall be entitled to complete access to
any technology licensed to it hereunder and all embodiments of such technology.
Subject to applicable law to the contrary, such embodiments of the technology
shall be delivered to Licensee not later than (a) the commencement of bankruptcy
proceedings against Licensor, unless Licensor elects to perform its obligations
under this Agreement, or (b) if not delivered under (a) above, upon the
rejection of this Agreement by or on behalf of Licensor.

                                   ARTICLE 6

                            PATENTS AND INFRINGEMENTS

         6.1 PURSUIT AND MAINTENANCE OF PATENT RIGHTS. Licensor shall, at its
own expense, file, prosecute and maintain Patent Rights. Licensor agrees to keep
Licensee informed as to the status of the Patent Rights and shall provide
Licensee with copies of all filings and correspondence of a substantive nature
with respect to patents or patent applications relating to the Patent Rights to
be made or sent to the United States Patent and Trademark Office or its
counterpart in any country of the Territory and copies of all correspondence of
a substantive nature that Licensor receives from such Persons with respect to
the Patent Rights. In the event that Licensor chooses not to prosecute a patent
in the Territory in the case of certain Intellectual Property or chooses not to
prosecute a patent in a certain country in the Territory that is based upon the
same patentable subject matter upon which Patent Rights are based, then Licensee
shall be entitled to prosecute such patent and Licensor shall reasonably
cooperate with Licensee in such prosecution; provided however that the
prosecution by Licensee of any patent pursuant to this Section shall not create
any ownership interest in such Intellectual Property or in such patentable
subject matter by Licensee that Licensee would not otherwise have hereunder.

         6.2 NOTICE OF INFRINGEMENT. Each party shall promptly notify the other
of any conflicting use or any act of infringement or appropriation of any Patent
Right by unauthorized Persons which comes to its attention.

                                       15

<PAGE>

         6.3 ENFORCEMENT AND DEFENSE. Upon becoming aware of a conflicting use
or an act of infringement, and communicating about the same pursuant to Section
6.2 above, Licensee shall discuss with Licensor the nature of and circumstances
surrounding such conflicting use or act of infringement. Subject to the consent
of Licensor, which consent shall not be unreasonably withheld, Licensee shall
thereafter, at its own expense, have the right but not the obligation to
initiate actions and take steps relating to such conflicting use or act of
infringement. Licensee may settle any dispute with a Third Party regarding such
conflicting use or act of infringement; provided that Licensee shall not have
the right to settle, compromise or take any action in any dispute which
diminishes, limits or inhibits the scope, validity or enforceability of the
Patent Rights without the express written consent of Licensor. In the event that
Licensee exercises its rights under this Section 6.3, Licensee agrees to keep
Licensor fully informed of all developments in connection with any settlements
and negotiations and to consult with Licensor prior to making any final
settlement, consent judgment or other voluntary disposition of the matter. If
Licensee chooses not to take or continue any action or step relating to such
conflicting use or act of infringement, Licensor shall have the right to engage
in negotiations and proceedings relating to such conflicting use or act of
infringement solely at its own expense; provided that it keeps Licensee fully
informed of the progress of such negotiations and proceedings and consults with
Licensee prior to making any final settlement, consent judgment or other
voluntary disposition of the matter. Each party agrees to cooperate with the
other to the fullest extent possible with respect to any negotiations or
proceedings under this Section 6.3.

         6.4 EQUITABLE DIVISION OF RECOVERIES BY LICENSEE. In the event that
Licensee elects to initiate actions or take steps relating to a conflicting use
or act of infringement pursuant to Section 6.3 above, and Licensee is thereby
able to recover from a Third Party by settlement or otherwise any damages or
other compensation in respect of such conflicting use or act of infringement,
such damages and other compensation shall be divided equitably between Licensee
and Licensor in a manner commensurate with the division of economic benefits
relating to sales of Licensed Products contemplated by this Agreement.

                                   ARTICLE 7

                                 CONFIDENTIALITY

         7.1 Except as expressly set forth in this Article 7, each party shall,
and shall cause its Affiliates and its and their respective officers, directors,
employees, agents and subcontractors (collectively, "Representatives") to, keep
confidential any and all technical, commercial, scientific and other proprietary
data, processes, documents or other information (whether in oral, written or
electronic form) or physical object (including, without limitation, intellectual
property, marketing data, agreements between any party and a Third Party,
license applications, and business plans and projections of any party) acquired
from the other party, its Affiliates or any of their respective Representatives
in respect of the transactions contemplated by this Agreement and which relate
(in the case of a party) to the other party or any of its Affiliates or their
respective businesses or products ("Confidential Information"), and each party
shall not disclose directly or indirectly, and shall cause its respective
Affiliates and Representatives not to disclose directly or indirectly, any
Confidential Information to anyone outside such Person, such Affiliates and
their respective Representatives, except that the 

                                       16

<PAGE>

foregoing restriction shall not apply to any information disclosed hereunder to
any Person if such Person (the "Receiving Person") can demonstrate that such
Confidential Information:

              (a) is or hereafter becomes generally available to the trade or
         public other than by reason of any breach hereof;

              (b) was already known to the Receiving Person or such Affiliate or
         Representative as shown by written records;

              (c) is disclosed to the Receiving Person or such Affiliate or
         Representative by a third party who has the right to disclose such
         information;

              (d) is developed by or on behalf of the Receiving Person or any of
         its Affiliates independently, without reliance on Confidential
         Information received hereunder; or

              (e) is, based on such Person's good faith judgment with the advice
         of counsel, otherwise required to be disclosed in compliance with
         applicable Legal Requirements by a Public Authority (and, in such case,
         such information shall remain Confidential Information for all other
         purposes unless and until subparagraphs (a) through (d) above otherwise
         apply).

         7.2 Except in furtherance of their respective rights and obligations
hereunder, each party agrees that it shall not (and shall not permit any of its
Affiliates to) at any time use any Confidential Information in the conduct of
its businesses without the prior written consent of the other party. The
obligations set forth in this Article 7 shall extend to copies, if any, of
Confidential Information made by any of the Persons referred to in Section 7.1
and to documents prepared by such Persons which embody or contain Confidential
Information, and to any electronic data files containing Confidential
Information.

         7.3 Each party shall deal with Confidential Information so as to
protect it from disclosure with a degree of care not less than that used by it
in dealing with its own information intended to remain exclusively within its
knowledge and shall take reasonable steps to minimize the risk of disclosure of
Confidential Information.

         7.4 The obligations set forth in this Article 7 shall survive the
expiration, termination or assignment of this Agreement for a period of []*
thereafter.

         7.5 Within thirty (30) days after the termination of this Agreement,
any Receiving Person shall (and shall cause its Affiliates and Representatives
to), at the option of the person making disclosure (the "Disclosing Person"),
return to the Disclosing Person or destroy all Confidential Information in its
or their possession; provided, however, that the Receiving Person may, upon
notice to the Disclosing Person, retain in its legal files or in the office of
outside legal counsel one copy of any document solely for use in legal
proceedings to which such document relates and for archival purposes. Such
notice shall set forth, in reasonable detail, a list of the documents so
retained.

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       17

<PAGE>

         7.6 Licensor agrees to use reasonable efforts to protect the
confidentiality, if applicable, of Technology that it licenses outside the Field
of Use in a manner commensurate with the manner in which such confidentiality is
protected hereunder.

                                   ARTICLE 8

                    REPRESENTATIONS, WARRANTIES AND COVENANTS

         8.1 Representations and Warranties of Licensee.

              (a) Licensee is a corporation duly incorporated and validly
         existing and (to the extent applicable) in good standing under the laws
         of its jurisdiction of organization, with the corporate power to own,
         lease and operate its properties and to carry on its business as now
         conducted.

              (b) Licensee has all necessary corporate power and authority to
         enter into this Agreement and to consummate the transactions
         contemplated hereby.

              (c) The execution, delivery and performance of this Agreement by
         License does not conflict with or contravene the articles or
         certificate of incorporation or by-laws, regulations or partnership
         agreement (or other comparable governing instruments with different
         names) of Licensee, nor will the execution, delivery or performance of
         this Agreement conflict with or result in a breach of, or entitle any
         party thereto to terminate, any material agreement or instrument to
         which Licensee is a party, or by which any of its assets or properties
         is bound.

              (d) This Agreement has been duly authorized, executed and
         delivered by Licensee and constitutes a legal, valid and binding
         agreement of Licensee, enforceable against Licensee in accordance with
         its terms, except as enforceability may be limited by bankruptcy,
         insolvency, moratorium, reorganization or other similar laws affecting
         creditors' rights generally.

         8.2 REPRESENTATIONS, WARRANTIES AND COVENANTS OF LICENSOR.

              (a) Licensor is a corporation duly incorporated and validly
         existing as a corporation and in good standing under the laws of the
         State of Delaware, with the corporate power to own, lease and operate
         its properties and to carry on its business as now conducted.

              (b) Licensor has all necessary corporate power and authority to
         enter into this Agreement and to consummate the transactions
         contemplated hereby.

              (c) The execution, delivery and performance of this Agreement by
         Licensor does not conflict with or contravene its certificate of
         incorporation or by-laws, nor will the execution, delivery or
         performance of this Agreement conflict with or result in a breach of,
         or entitle any party thereto to terminate, any material agreement or
         instrument to which Licensor is a party, or by which any of its assets
         or properties is bound. No Third Party has any right, title or interest
         in or to any Technology in the Fields of Use.

                                       18

<PAGE>

              (d) This Agreement has been duly authorized, executed and
         delivered by Licensor and constitutes a legal, valid and binding
         agreement of Licensor, enforceable against Licensor in accordance with
         its terms, except as enforceability may be limited by bankruptcy,
         insolvency, moratorium, reorganization or other similar laws affecting
         creditors' rights generally.

              (e) Licensor owns or has rights to use and exploit under licenses
         (and to license or sublicense) all of its rights under the Technology.
         There have been no material claims made against Licensor asserting the
         invalidity or unenforceability of, or with respect to the Patent
         Rights, the misuse of, the Patent Rights or Licensed Know-How, nor is
         Licensor aware that any such claims exist. Licensor has not received a
         notice of conflict of the Technology with the asserted rights of
         others, or otherwise challenging its rights to use any of the
         Technology. None of the rights of Licensor under the Patent Rights or
         Licensed Know-How will be adversely affected by the execution, delivery
         or performance of this Agreement, or the consummation of the
         transactions contemplated herein.

              (f) Licensor has not filed for protection under the United States
         Bankruptcy Code, as amended (the "Code"), nor does it have any
         intention of doing so. No Third Party has filed or commenced, nor to
         the knowledge of Licensor has any Third Party threatened to file or
         commence, a proceeding under the Code against Licensor.

         8.3 INDEMNIFICATION.

              (A) INDEMNITY BY LICENSEE. Licensee hereby agrees to []*

              (B) INDEMNITY BY LICENSOR. Licensor hereby agrees to []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       19

<PAGE>

              (C) INDEMNIFICATION PROCEDURES.

                   (i) Any party entitled to indemnification under paragraph (a)
              or (b) of this Section 8.3 (an "Indemnified Party") shall promptly
              notify the party potentially responsible for such indemnification
              (the "Indemnifying Party") upon becoming aware of any claim or
              claims asserted or threatened against such Indemnified Party which
              could give rise to a right of indemnification under this
              Agreement; PROVIDED, HOWEVER, that the failure to give such notice
              shall not relieve the Indemnifying Party of its indemnity
              obligation hereunder except to the extent that such failure
              prejudices its rights hereunder.

                   (ii) the Indemnifying Party shall have the right to 
              defend, at its sole cost and expense, such claim by all 
              appropriate proceedings, which proceedings shall be prosecuted 
              diligently by the Indemnifying Party to a final conclusion or 
              settled at the discretion of the Indemnifying Party; PROVIDED, 
              HOWEVER, that the Indemnifying Party may not enter into any 
              compromise or settlement unless (x) the Indemnified Party 
              consents thereto, which consent shall not be unreasonably 
              withheld, or (y) such compromise or settlement includes as an 
              unconditional term thereof the giving by each claimant or 
              plaintiff to the Indemnified Party of a release from all 
              liability in respect of such claim.

                   (iii) The Indemnified Party may participate in, but not
              control, any defense or settlement of any claim by the
              Indemnifying Party pursuant to this Section 8.3 and shall bear its
              own costs and expenses with respect to such participation;
              PROVIDED, HOWEVER, that the Indemnifying Party shall bear such
              costs and expenses if counsel for the Indemnifying Party shall
              have reasonably determined that such counsel may not properly
              represent both the Indemnifying Party and the Indemnified Party.

                   (iv) If the Indemnifying Party fails to notify the
              Indemnified Party within twenty (20) days after receipt of notice
              of a claim in accordance with Section 8.3(c)(i) hereof that it
              elects to defend the Indemnified Party pursuant to this Section
              8.3(c), or if the Indemnifying Party elects to defend the
              Indemnified Party but fails to prosecute or settle the claim
              diligently, then the Indemnified Party shall have the right to
              defend, at the sole cost and expense of the Indemnifying Party,
              the claim by all appropriate proceedings, which proceedings shall
              be diligently prosecuted by the Indemnified Party to a final
              conclusion or settled; PROVIDED, HOWEVER, that in no event shall
              the Indemnifying Party be required to indemnify the Indemnified
              Party for any amount paid or payable by the Indemnified Party in
              the settlement of any such claim agreed to without the consent of
              the Indemnifying Party, which shall not be unreasonably withheld.

                                       20

<PAGE>

                                   ARTICLE 9

                 DILIGENCE IN COMMERCIALIZING LICENSED PRODUCTS

         9.1 GENERAL. Licensee shall use commercially reasonable efforts to
promptly and fully research, develop, register, market and sell and to continue
to market and sell Licensed Product in each country in which Licensee reasonably
determines that there is a market potential for such Licensed Product.

         9.2 NOTIFICATION. Licensee shall promptly notify Licensor in writing if
at any time Licensee ceases to promptly and fully research, develop and/or
obtain regulatory approval for and/or market and sell a Licensed Product in any
country.

         9.3 REVERSION OF RIGHTS TO LICENSOR. If, at any time subsequent to the
payment of the Reimbursement Payments, Licensee fails to use commercially
reasonable efforts to promptly and fully research, develop, register, market and
sell and to continue to market and sell Licensed Product in any country, the
rights and licenses granted to Licensee with respect to such country shall
terminate, upon []* prior written notice to Licensee from Licensor,
subject to Licensee's right to reestablish in good faith its efforts pursuant to
Section 9.1 above with respect to such country within such []* period.

                                   ARTICLE 10

                             ACCOUNTING AND RECORDS

         10.1 REPORTS. Licensee agrees to make quarterly written reports to
Licensor within ninety (90) days after the end of each calendar quarter in which
royalties are due under this Agreement, stating in each such report with respect
to Licensed Products, the number, description, and aggregate Net Sales of
Licensed Products sold during the calendar quarter and upon which a royalty is
payable under Article 3 above.

         10.2 PAYMENT. Concurrently with the making of each such report of
Section 10.1, Licensee shall pay to Licensor the royalties at the rate specified
in Section 3.3, if any such royalties are due. All payments by Licensee to
Licensor hereunder shall be made in United States dollars. If any currency
conversion shall be required in connection with the calculation of royalties or
the payment of other compensation hereunder, such conversion shall be made by
using the rate of exchange published in The Wall Street Journal for the last
business day of the applicable calendar quarter.

         10.3 WITHHOLDING TAXES. The payments referred to in Article 3 above
shall be net of all withholding taxes and other taxes that Licensee or any of
its Affiliates are required by law to withhold or pay; PROVIDED, HOWEVER, that
if, in regard to any withholding tax paid by Licensee, Licensor is able to
realize a benefit in the form of a corresponding tax credit that it is actually
able to use to reduce its tax payments, then Licensor shall reimburse Licensee
for such withholding tax to the extent of such realized benefit. Licensor shall
furnish Licensee with appropriate documents supporting application of the most
favorable rate of withholding tax 

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       21

<PAGE>

available under applicable tax treaties and shall use commercially reasonable
efforts to secure all tax credits in respect of withholding taxes paid by
Licensee hereunder available to it.

         10.4 RECORDS; INSPECTION.

              (a) Licensee shall keep complete, true and accurate books of
         account and records for the purpose of determining the amounts payable
         to Licensor under this Agreement. Such books and records shall be kept
         at Licensee's principal place of business for at least three (3) years
         following the end of the calendar quarter to which they pertain, and
         will be open for inspection during such three (3) year period by an
         independent public accountant not providing accounting services to
         Licensor, Licensee or any of their respective Affiliates that is
         reasonably acceptable to both parties, for the purpose of verifying
         Licensee's quarterly written reports. Such inspections may be made no
         more than once each calendar year, during normal business hours and
         upon thirty (30) days prior notice. Any such information shall be
         considered to be Confidential Information of Licensee.

              (b) Inspections conducted under this Section 10.4 shall be at the
         expense of Licensor, unless an underpayment exceeding five percent (5%)
         of the royalties paid during the period covered by the inspection is
         established in the course of any such inspection, whereupon all costs
         relating thereto, as well as any unpaid royalties due and owing to
         Licensor, shall be paid by Licensee within thirty (30) days after the
         notification by Licensor to Licensee that an underpayment has been
         discovered.

                                   ARTICLE 11

                                  MISCELLANEOUS

         11.1 PUBLICITY. Licensee and Licensor shall cooperate in the
preparation of a mutually-agreeable press release and other publicity disclosing
the existence of this Agreement and their business relationship. Except for the
information disclosed in such press release or publicity, neither Licensee nor
Licensor shall disclose the existence or any terms of this Agreement without the
prior written consent of the other party (which consent shall not be
unreasonably withheld), except for such limited disclosure as may be reasonably
necessary to either party's bankers, investors, attorneys or other professional
advisors, or in connection with a merger or acquisition, or as may be required
by law in the offering of securities or in securities or regulatory filings or
otherwise.

         11.2 WAIVER. It is agreed that no waiver by any party hereto of any
breach or default of any of the covenants or agreements herein set forth shall
be deemed a waiver as to any subsequent and/or similar breach or default.

         11.3 INDEPENDENT CONTRACTORS. The relationship of the parties hereto is
that of independent contractors. Neither Licensor nor Licensee hereto is an
agent, partner or joint venturer of the other for any purpose.

         11.4 COMPLIANCE WITH LAWS. In exercising their rights under this
Agreement, both parties shall fully comply with the requirements of any and all
applicable laws, regulations, 

                                       22

<PAGE>

rules and orders of any governmental body having jurisdiction over the exercise
of rights under this Agreement.

         11.5 NOTICES. Any notice required or permitted to be given to the
parties hereto shall be deemed to have been properly given if delivered in
person or when received if mailed by first class certified mail or sent by
facsimile to the other party at the address or facsimile number, as applicable,
indicated below or to such other addresses or facsimile numbers as may be
designated in writing by the parties from time to time during the term of this
Agreement.

Licensor:                    OraVax, Inc.
                             38 Sidney Street
                             Cambridge, Massachusetts  02139

                             Attention:  Lance Gordon

                             Telephone:  (617) 494-1339
                             Facsimile:  (617) 494-0924

with a copy to:              Michael E. Lytton, Esq.
                             Palmer & Dodge LLP
                             One Beacon Street
                             Boston, Massachusetts 02108

                             Telephone:  (617) 573-0100
                             Facsimile:  (617) 227-4420

Licensee:                    Pasteur Merieux Serums & Vaccins S.A.
                             58, avenue Leclerc
                             69007 Lyon, France
                             Attention:        Senior Vice President, Corporate 
                                               and Legal Affairs, and General 
                                               Counsel

                             Telephone:  011.33.4.37.37.77.84
                             Facsimile:  011.33.4.37.37.70.61

with a copy to:              L. Kevin O'Mara, Jr., Esq.
                             Akin, Gump, Strauss, Hauer & Feld, L.L.P.
                             590 Madison Avenue
                             New York, NY  10022

                             Telephone: (212) 872-1021
                             Facsimile:  (212) 872-1002


         11.6 COMPLETE AGREEMENT. It is understood and agreed among the parties
that this Agreement and the Dengue License constitute the entire agreement with
respect to the subject matter of this Agreement, both written and oral, among
the parties, and that all prior 

                                       23

<PAGE>

agreements respecting the subject matter hereof, either written or oral,
expressed or implied, shall be abrogated, canceled, and are null and void and of
no effect. No amendment or change hereof or addition hereto shall be effective
or binding on any of the parties hereto unless reduced to writing and executed
by the respective duly authorized representatives of each of the parties hereto.

         11.7 SEVERABILITY. In the event that any provision of this Agreement
becomes or is declared by a court of competent jurisdiction to be illegal,
unenforceable or void, this Agreement shall continue in full force and effect
without said provision and the parties shall exert their best efforts to amend
this Agreement to include a provision which is valid, legal and enforceable and
which carries out the original intent of the parties.

         11.8 COUNTERPARTS AND HEADINGS. This Agreement may be executed in
counterparts, each of which shall be deemed to be an original and both together
shall be deemed to be one and the same agreement. All headings and any cover
page or table of contents are inserted for convenience of reference only and
shall not affect the Agreement's meaning or interpretation.

         11.9 GOVERNING LAW. All matters affecting the interpretation, validity
and performance under this Agreement shall be governed by the internal laws of
the State of New York, without regard for its conflict of laws principles.

         11.10 FORCE MAJEURE. No party shall be liable to the other, or be in
default under the terms of this Agreement, for its failure to fulfill its
obligations hereunder to the extent such failure arises for any reason beyond
its control including, without limitation, strikes, lockouts, labor disputes,
acts of God, acts of nature, acts of governments or their agencies, fire, flood,
storm, power shortages or power failure, war, sabotage, inability to obtain
sufficient labor, raw materials, fuel or utilities, or inability to obtain
transportation (each, an "Event of Force Majeure"); provided that the party
relying on the provisions of this Section 11.10 shall forthwith give to the
other notice of its inability to observe or perform the provisions of this
Agreement and the reasons therefor; and provided further that the suspension of
the obligations of the party so affected shall continue only for so long as such
Event of Force Majeure continues.

         11.11 ASSIGNMENT. This Agreement shall not be assignable by any party
without the prior written consent of the other (which consent shall not be
unreasonably withheld), except that any party may assign this Agreement to an
Affiliate or to a successor in interest or transferee of all or substantially
all of its assets.

         11.12 SUCCESSORS. Subject to the limitations on assignment herein, this
Agreement shall be binding upon and inure to the benefit of the successors in
interest and assigns of Licensor and Licensee. In order for such assignment to
be effective any such assignee of a party's interest shall expressly assume in
writing the performance of all the terms and conditions of this Agreement to be
performed by said party and such assignment shall not relieve the assignor of
any of its obligations under this Agreement.

         11.13 EXPENSES. Licensee and Licensor shall each bear its own expenses,
including, without limitation, the fees and disbursements of its respective
counsel and 

                                       24

<PAGE>

accountants, in connection with the negotiation and execution of this Agreement
and the consummation of the transactions contemplated hereby.

                                       25

<PAGE>

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement, in
one or more counterparts, on the day and year first above written.

ORAVAX, INC.                             PASTEUR MERIEUX SERUMS & VACCINS S.A.


By:                                      By:
   ------------------------                 ------------------------
     Name:                                  Name:  Paul Kirkconnell
     Title:                                 Title:  Corporate Vice President



<PAGE>

                                   APPENDIX A

            INITIAL MEMBERSHIP OF RESEARCH AND DEVELOPMENT COMMITTEE*



[]*





- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.




<PAGE>

                                   SCHEDULE A



                                  PATENT RIGHTS




[]*




- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


<PAGE>


                                                                      ANNEX B TO
                                                                   EXHIBIT 10.10

                       U.S. HEPATITIS C LICENSE AGREEMENT

            This LICENSE AGREEMENT (the "Agreement" or "License") is entered
into as of __________, 1999 by and between ORAVAX MERIEUX CO., a general
partnership organized under the laws of Massachusetts, ("Licensee") and ORAVAX,
INC., a corporation organized under the laws of the State of Delaware, ("OraVax"
or "Licensor").

                               W I T N E S S E T H

            WHEREAS, Licensor owns or possesses certain proprietary rights and
know-how relating to vaccines for the prevention, treatment or cure of hepatitis
C in humans (the "Field");

            WHEREAS, Licensee desires to obtain from Licensor, and Licensor
desires to grant to Licensee, a license under Licensor's proprietary rights and
know-how to research, develop, manufacture, market, sell and distribute Target
Products (as defined below);

            NOW, THEREFORE, in consideration of the mutual promises, conditions,
covenants and undertakings hereinafter set forth, the parties hereto, intending
to be legally bound, hereby agree as follows:

      1.  DEFINITIONS.

          All capitalized terms used in this Agreement and not otherwise defined
herein shall have the meanings set forth in the Master Agreement (as defined
below) and such definitions are incorporated herein by reference.

          1.1  "Affiliate" shall mean, with respect to either OraVax or 
Licensee, (i) any Person (including a partnership) of which securities or other
ownership interests representing 50% or more of the equity or 50% or more of the
ordinary voting power are, at the time such determination is being made, owned,
Controlled or held, directly or indirectly, by such Party, or (ii) any other
Person which, at the time such determination is being made, is Controlling,
Controlled by or under common Control with, such Party.

          1.2  "Basic Technology" shall mean the inventions described in the
patents and patent applications set forth on SCHEDULE A attached hereto.

          1.3  "Collaboration" refers to the time period during which the U.S.
Partnership is in effect.

          1.4  "Control", whether used as a noun or verb, shall mean the 
possession, directly or indirectly, of the power to direct, or cause the 
direction of, the management or policies of a Person, whether through the 
ownership of voting securities, by contract or otherwise


<PAGE>

          1.5  "Improvements" shall mean any Technology which enhances the
effectiveness of or is an improvement upon any aspect of the OraVax Technology,
which is conceived, discovered, actually reduced to practice, obtained by,
licensed (with right to sublicense) or otherwise acquired by one or more of the
Parties and/or one or more of the Partnerships, or by one or more of their
Controlled Affiliates after the date of this Agreement and prior to the
termination of the Collaboration. Improvements shall include, by way of
illustration but not limitation, enhancements in the form of improving the
process for making the Target Products so that they are made in a less expensive
or more expeditious manner, increasing the immunological or therapeutic
effectiveness of the Target Products, discovering additional biological
information as it relates to the expression of the Target Products, discovering
additional substitutions in the Target Products which increase immunological or
therapeutic effectiveness and discovering new applications of the Target
Products in other fields of use.

          1.6  "Independent Improvement" shall mean any Improvement conceived,
discovered, developed, licensed or otherwise acquired after the date of this
Agreement but prior to any termination of the Collaboration, which was
conceived, discovered, developed, licensed (with the right to sublicense) or
otherwise acquired by either Licensee, OraVax or their Controlled Affiliates due
to funding outside of the Programs by such Party or its Controlled Affiliate.

          1.7  "Licensed Technology" shall mean, collectively, the OraVax
Technology and OraVax' Independent Improvements.

          1.8  "Master Agreement" shall mean that certain Master Agreement by
and between PMC and OraVax dated as of March 31, 1995, as amended by that
certain Amendment Agreement dated November 2, 1998 and that certain Amendment
Agreement dated as of the date hereof.

          1.9  "Net Sales" shall mean with respect to sales of the product
concerned for any period for which the applicable calculation is being made, the
gross amount invoiced to customers less (i) returns and allowances, (ii) trade
and/or quantity discounts, (iii) sales, use, value-added, excise taxes and
similar taxes and duties, (iv) an additional amount which would reasonably
approximate the actual cash discounts, if any, given to customers.

          1.10      "OraVax Technology" shall mean the Basic Technology and any
other Technology other than Severable Technology which (i) relates and is useful
to research, development, use and exploitation of Target Products and (ii) is
owned, licensed or otherwise held by OraVax or any of its Controlled Affiliates
at the date of this Agreement with the right to license or sublicense the same
to the Partnerships.

          1.11 "OraVax Technology Agreement" shall mean any agreement or
understanding pursuant to which OraVax has acquired rights to any of the
Licensed Technology.

          1.12 "Partnership(s)" shall mean, collectively, the SNC and the U.S.
Partnership and, individually, either the SNC or the U.S. Partnership.

          1.13 "Person" shall mean any natural person, corporation, firm,
business trust, joint venture, association, organization, company, partnership
or other business entity, or any government, or agency or political subdivision
thereof.


                                       2

<PAGE>

          1.14 "PMC" shall mean Pasteur Merieux Serums & Vaccins S.A., a French
SOCIETE ANONYME, whose registered head office is located at 58, avenue Leclerc,
69007 Lyon, France.

          1.15 "Proprietary Rights" shall mean patent rights (including, but not
limited to, all granted patents and pending patent applications), copyrights,
trade secret rights and similar rights, and licenses and sublicenses under such
rights.

          1.16 "Severable Technology" shall mean any Technology, which (i) is
not Licensed Technology, and (ii) results during the Collaboration from funding
outside the Collaboration and has or was expected to have applications and uses
outside of the Field but (iii) is useful or potentially useful to the research,
development, manufacture, use or exploitation of Target Products. Severable
Technology shall include, by way of illustration but not limitation, adjuvants,
microencapsulation techniques or any innovation allowing a change in the means
of delivery or the addition of another antigen for use against hepatitis C.
Without limiting the generality of the foregoing, the parties agree that []* 
constitutes Severable Technology.

          1.17 "SNC" shall mean the SOCIETE EN NOM COLLECTIF established by
OraVax and PMC under French law to pursue the Collaboration outside the United
States.

          1.18 "Sublicensed Affiliate" shall mean, with respect to either OraVax
or Licensee, any Affiliate with an express or implied (e.g., under a
distribution agreement) license or sublicense to research, develop, make, have
made, market, sell, distribute or use Target Products.

          1.19 "SNC License Agreement" shall mean that certain license agreement
of even date herewith by and between OraVax, as licensor, and the SNC, as
licensee.

          1.20 "Target Product" shall mean any vaccine for the prevention,
treatment or cure of hepatitis C infections in humans; provided, however, that
any product containing one or more antigens for use against indications other
than hepatitis C shall not be a Target Product unless both Parties shall agree
in writing to extend the definition to include such product. In addition, no
product shall be deemed a Target Product unless either (i) such product utilizes
a method, vaccine or composition described in whole or in part in any of the
patents or any of the original patent applications of the pending patent
applications listed in SCHEDULE A attached hereto or (ii) the research,
development, manufacture or use of such product has or will use Technology
described in whole or in part in any of the patents or any of the original
patent applications of the pending patent applications listed in SCHEDULE A
attached hereto. All references in this definition to patents and patent
applications are solely for the purpose of incorporating the descriptions of the
method, vaccine, composition and/ or Technology contained therein and shall not
be deemed to require that a patent shall issue from any pending patent
application or deemed to require that any patent, whether existing or
subsequently issued, shall be valid or enforceable. Any product that is not a
Target Product shall be deemed a Target Product only if during the term of the
Collaboration the Executive Committee determines to extend the definition of
Target Product to such product.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       3

<PAGE>

          1.21 "Technology" shall mean:

          (a) the subject matter of any and all relevant patents and/or pending
patent applications, including, but not limited to, the information contained in
such patents and patent applications, any divisions, continuations, and
continuations-in-part based thereon, any patents which may issue therefrom and
any reissues, patents of addition or importation; and

          (b) any and all relevant inventions (whether or not patentable),
ideas, processes, formulas, technical information, trade secrets, developments,
discoveries, data, the subject matter of any and all copyrights, drawings,
techniques, documents, laboratory note books, pre-clinical and clinical case
reports and report forms, scientific and medical reports, models, and know-how,
including by way of example and in no way limiting the foregoing, any biological
materials and chemical compounds including but not limited to structural genes,
genetic sequences, promoters, enhancers, probes, linkage probes, vectors, hosts,
plasmids, peptides, polypeptides, transformed cell lines, transgenic animals,
proteins, biological modifiers, antigens, reagents, hybridomas, antibodies,
toxins, lectins, enzymes, lipids, hormones, viruses, cells or parts of cells,
cell lines, fragments of any of the foregoing, and any other biologically active
material or compound, whether or not occurring naturally or howsoever derived,
modified, conjugated, cross-linked, immobilized, reduced, purified or produced,
whether by recombinant DNA techniques and/or otherwise.

          1.22 "United States" shall mean the United States of America and its
dependent territories and possessions.

          1.23 "U.S. Partnership" shall mean the partnership established by PMC
and OraVax to pursue the Collaboration in the United States.

     2.   LICENSE GRANT.

          2.1 ORAVAX LICENSE TO THE U.S. PARTNERSHIP. Subject to all of the
terms and limitations of this Agreement, OraVax hereby grants to the U.S.
Partnership, a nationwide license under its Proprietary Rights to use the
Licensed Technology in the Field to research, develop, make, have made, market,
sell, distribute and use the Target Products in the United States. The foregoing
license is limited, and may be exercised solely as provided herein; provided,
however, that any such limitation is without prejudice to the U.S. Partnership's
exercise of any rights it may now hold or hereafter obtain independently in
respect of any Technology other than the Licensed Technology.

          2.2 UNDERTAKINGS. Except as provided herein, the licensee granted
under Section 2.1 hereof shall be exclusive in the Field. The U.S. Partnership
undertakes that during the term of the Collaboration it shall commercially
exploit its interest in the Licensed Technology within the Field in the United
States.

     3.   COMPENSATION.

          3.1 LICENSE FEE. In consideration of the licenses granted hereunder,
Licensee shall pay to Licensor a license fee of []* on the later to
occur of []*


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       4

<PAGE>


[]*

          3.2 MILESTONE FEES. Licensee shall, with the exception of clause 
(vi) hereof, pay to Licensor the amounts specified below within []* following 
the accomplishment by Licensee, of the corresponding event set forth below 
(each, a "Milestone"):

               (i)  []*


               (ii) []*


               (iii) []*


               (iv) []*


               (v)  []*


               (vi) []*


          The foregoing amounts shall be paid by Licensee only once.

          3.3 ROYALTIES. Licensee shall pay Licensor a minimum royalty of []*
which shall be payable in any year when the U.S. Partnership have any sales of
Target Products in the United States, which shall be paid with reasonable
promptness upon receipt of an invoice following the close of the year concerned.

          3.4 TAXES. Licensee may withhold from any payments due the Licensor
under this Agreement the appropriate withholding taxes, if any, applicable to
such payments. Licensee shall remit the withheld taxes to the appropriate taxing
authorities, and shall provide to Licensor an official certificate of payments
of such taxes or any other documentation and evidence necessary to verify
payment thereof.

          3.5 RECORDS, ACCOUNTING. If the Collaboration is terminated pursuant
to Section 11 hereof, PMC and OraVax and their successors and assigns shall keep
and maintain detailed and accurate books and records with regard to Net Sales,
royalties, payments received from sublicensees and payments due to the other and
the calculation thereof.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       5

<PAGE>

          4. ORAVAX' RETAINED RIGHTS. Except for the license granted to the U.S.
Partnership under Section 2.1 hereof, and the license granted to the SNC
pursuant to the SNC License Agreement, OraVax retains all right, title and
interest to the Licensed Technology, subject to all the terms, conditions,
limitations and restrictions of this Agreement, the SNC License Agreement and
the Master Agreement. OraVax' retained rights include, but are not limited to,
(a) the right to use the Licensed Technology for research, development and
manufacturing the Target Products in the Field on behalf of the Collaboration,
and (b) the right to use and exploit the Licensed Technology outside the Field.

          5. LIMITED RIGHT TO GRANT SUBLICENSES. During the term of the
Collaboration the U.S. Partnership shall only be entitled to grant sublicenses
to use the Licensed Technology within the Field for the purposes and benefit of
the Collaboration.

          6. THIRD PARTY AGREEMENTS. The U.S. Partnership agrees to comply with
all terms, conditions and restrictions applicable to it imposed by the OraVax
Technology Agreements as the same exist as of the date hereof and any agreements
with third parties relating to any OraVax Independent Improvements.

     7.   IMPROVEMENTS; DISCLOSURE.

          7.1 INDEPENDENT IMPROVEMENTS. Any and all Proprietary Rights to any
Independent Improvement conceived, discovered, developed, licensed or otherwise
acquired during the term of the Collaboration, shall, as between the Licensee
and OraVax, be owned by the party that expended the funding for the Independent
Improvement. Notwithstanding the foregoing, any OraVax Independent Improvement
during the term of the Collaboration shall automatically be included within the
license granted under Section 2.1 hereof and automatically included in any
sublicenses granted in accordance with this Agreement without any change or
adjustment to the payments due between the parties hereunder.

          7.2 DISCLOSURE. OraVax and the Licensee agree to promptly disclose to
each other any Improvement which either party conceives, discovers, develops,
licenses or otherwise acquires rights to, during the term of the Collaboration;
provided, however, that if OraVax or the Licensee is offered or obtains
something which would otherwise be an Improvement from a third party but which
is subject to restrictions on disclosure and use, then such party shall notify
the other party of the existence and restrictions on the disclosure and use of
the Improvement and shall consult with the other party on a good faith basis as
to whether the parties need to jointly negotiate a license to obtain disclosure
and use of the Improvement for the purposes of the Collaboration; and, provided,
further, that except as set forth in the foregoing proviso, there shall be no
restrictions on the right of the Licensor to receive Improvements hereunder,
including, but not limited to, pursuant to Section 6 above.

          8. SEVERABLE TECHNOLOGY. OraVax and PMC hereby agree that Severable
Technology is not subject to, or included in, any license granted under this
Agreement. Severable Technology shall be owned by the party that conceives,
discovers, develops, licenses or otherwise acquires the same.


                                       6

<PAGE>

          9. CONFIDENTIALITY. The terms of this Agreement and all Licensed
Technology, Improvements, and all other information disclosed pursuant to this
Agreement shall be subject to the provisions of Article 21 of the Master
Agreement.

          10. PATENT MATTERS. Any and all matters relating to patent prosecution
and protection of a party's Proprietary Rights with respect to the Licensed
Technology and Independent Improvements thereto shall be determined in
accordance with Section 7.5 of the Master Agreement.

     11.  TERM AND TERMINATION.

          11.1 TERM. The term of this Agreement shall commence on the date
hereof and shall continue until the Partnership is terminated and dissolved as
set forth in the Master Agreement. In the event that the Partnership is
dissolved (i) both OraVax and PMC shall have co-exclusive rights to the Licensed
Technology, (ii) neither PMC nor OraVax shall have the right to grant
sublicenses of the Licensed Technology, and (iii) neither PMC nor OraVax shall
have the right, either on its own or pursuant to any agreement or arrangement
with a third party to manufacture, have manufactured, sell, have sold, market,
develop or distribute a product derived from the Licensed Technology without the
written consent of the other.

          11.2 TERMINATION. This Agreement shall terminate and all rights 
granted by Licensor hereunder shall revert to the Licensor in the event that 
[]* This Agreement shall also terminate and all rights granted by Licensor 
hereunder shall revert to Licensor in the event that PMC fails to make a 
required capital contribution necessary to permit the Partnership to make the 
payments set forth in Section 3.1 or 3.2 hereof.

          11.3 INCORPORATION BY REFERENCE AND SURVIVAL. Any accrued rights to
payment and any cause of action or remedies for breach of this Agreement shall
survive termination. Section 7.5 (Patent Matters) and Articles 17 (Arbitration),
18 (Indemnification) and 21 (Confidentiality) of the Master Agreement are hereby
incorporated herein by reference and shall survive for the purposes hereof in
accordance herewith without regard to any termination of the Master Agreement.
Without limiting the generality of the foregoing, the parties agree that this
Agreement constitutes a "Future Agreement" within the meaning of the Master
Agreement.

          11.4 TRANSFER OF TECHNOLOGY ON TERMINATION. Upon termination of this
Agreement, any documents, records, materials or other tangible manifestations of
the Licensed Technology shall be transferred, returned or retained in accordance
with the relevant provisions of the Master Agreement.

          11.5 REMEDIES. Termination is not the sole remedy under this Agreement
and, whether or not termination is effected, all other remedies will remain
available.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       7

<PAGE>

     12.  ARBITRATION. Any and all disputes in relation to any aspect of this
Agreement shall be settled by final and binding arbitration pursuant to
applicable provisions set forth in Article 17 of the Master Agreement.

     13.  PROPRIETARY RIGHTS. As of the Effective Time: (a) OraVax or one or
more of its Affiliates owns or has rights to use and exploit all OraVax
Technology; (b) there have been no material claims made against OraVax or any of
its Affiliates asserting the invalidity, unenforceability of, or misuse of, any
of OraVax' Proprietary Rights to the OraVax Technology; (c) neither OraVax nor
any of its Affiliates has received a notice from a third party indicating that
any aspect of the OraVax Technology may conflict with the asserted rights of
others, or otherwise challenging OraVax' rights to use any of the OraVax
Technology; (d) to OraVax' best knowledge, the present use by OraVax or any of
its Affiliates of such OraVax Technology does not violate or infringe in any
material respect any such rights of others or constitute a material breach under
any agreement with a third party; (e) the OraVax Technology Agreements are the
only agreements to which OraVax or any of its Affiliates are a party pursuant to
which payments may be due in respect of OraVax Technology; (f) the agreements
listed and described on Annex A hereto are the only agreements to which OraVax
or any of its Affiliates is a party affecting OraVax' rights to use and exploit
all of the OraVax Technology; (g) OraVax is in full compliance in all material
respects with the terms and conditions of each of the OraVax Technology
Agreements; (h) each of the OraVax Technology Agreements constitutes the valid
and binding obligations of OraVax and each other party thereto and shall be
enforceable against OraVax and, against each other party thereto in accordance
with its terms (subject, however, to any limitations with respect to enforcement
which may be imposed in connection with bankruptcy, insolvency, reorganization,
moratorium or other laws affecting the enforcement of creditors' rights
generally, and except that no representation or warranty is made as to the
availability of any equitable remedy in connection with the enforcement of any
term thereof). None of the rights of OraVax or any of its Affiliates to such
OraVax Technology will be adversely affected by the execution, delivery or
performance of this Agreement. OraVax and its Affiliates have taken all action
reasonably necessary, using its current standard business practices, to protect
such OraVax Technology.

EXCEPT AS SPECIFICALLY PROVIDED FOR IN THIS SECTION 13, ORAVAX DISCLAIMS ALL
WARRANTIES RELATING TO THE LICENSED TECHNOLOGY, EXPRESS OR IMPLIED, INCLUDING,
BUT NOT LIMITED TO, ANY WARRANTIES AGAINST INFRINGEMENT OF THIRD PARTY RIGHTS,
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

     14.  CERTAIN COVENANTS RELATING TO ORAVAX TECHNOLOGY. OraVax hereby 
covenants to []* in the event that, at any time or from time to time, the 
amount of any and all royalties and license or other fees which may be 
payable under the OraVax Technology Agreements to the extent that any such 
royalties exceed []* of net sales.

          OraVax covenants and agrees at all times during the Collaboration, and
thereafter so long as PMC or its Affiliates or successors and assigns has any
rights to any of the OraVax Technology, (i) to take all action reasonably
necessary to protect all of its rights to the OraVax Technology, including, but
not limited to, the OraVax Technology Agreements, (ii) to comply 


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       8

<PAGE>

fully with the terms and conditions of each of the OraVax Technology Agreements
(including, but not limited to any royalty or license (or other) fee
obligations) and otherwise maintain such Agreements in full force and effect;
(provided that OraVax shall not be responsible for adverse effects on the OraVax
Technology Agreements to the extent caused, by the actions of PMC or its
Controlled Affiliates or their successors and assigns unless expressly licensed
or authorized by OraVax pursuant to the Master Agreement or any Closing or
Future Agreement); and (iii) to promptly furnish PMC with copies of any and all
written notices OraVax or any of its directors, officers, employees, agents or
representatives may at any time receive in connection with any of the OraVax
Technology Agreements.

     15.  INDEMNIFICATION. Each of OraVax and the Licensee shall defend
indemnify and hold harmless the other and their respective Affiliates to the
full extent provided in Article 18 of the Master Agreement.

     16.  ASSIGNMENT. The rights and obligations of the parties under this
Agreement may not be assigned or transferred without the prior written consent
of the other.

     17.  EXPORT REGULATIONS. The U.S. Partnership hereby agrees to comply with
all export laws and restrictions and regulations of the Department of Commerce
of the United States or other United States, French or any other country's
agency or authority, and not to knowingly export, or allow the export or
re-export of any Technology, Target Product or any derivative or direct product
thereof, in violation of any such restrictions, laws or regulations, or, without
all required licenses and authorizations to Afghanistan, the People's Republic
of China or any Group Q, S, W, Y or Z country specified in the then current
Supplement No. 1 to Section 770 of the U.S. Export Administration Regulations
(or any successor supplement or regulations).

     18.  IMPORT REGULATIONS. This Agreement is subject to all of the United
States', France's (or any other country's, as appropriate) laws and regulations
controlling the import of drugs and biological products, technical data,
laboratory prototypes and other commodities and Technology.

     19.  NOTICES.

          Any notice or other communication required or permitted hereunder
shall be in writing and shall be deemed given when so delivered in person, by
overnight courier, by facsimile transmission (with receipt confirmed by
telephone or by automatic transmission report) or two business days after being
sent by registered or certified mail (postage prepaid, return receipt
requested), as follows:


                                       9

<PAGE>

          (a) if to Licensor, to:

                         OraVax, Inc.
                         38 Sidney Street
                         Cambridge, Massachusetts  02139
                         Attn:  Lance Gordon
                         Telephone:  (617) 494-1339
                         Facsimile:  (617) 494-0924

                         with a copy to:

                         Palmer & Dodge LLP
                         One Beacon Street
                         Boston, Massachusetts 02108
                         Attn: Michael Lytton, Esq.
                         Telephone: (617) 573-0100
                         Facsimile: (617) 227-4420

          (b) if to Licensee, to:

                         OraVax Merieux Co.
                         38 Sidney Street
                         Cambridge, Massachusetts 02139
                         Attn: Lance Gordon
                         with a copy to:

                         Pasteur Merieux Serums & Vaccins S.A.
                         58, avenue Leclerc
                         69007 Lyon, France
                         Attn:  Senior Vice President,
                                Legal and Corporate Affairs and General Counsel
                         Telephone: 011.33.4.37.37.77.84
                         Facsimile: 011.33.4.37.37.70.61

                         with a copy to:

                         Akin, Gump, Strauss, Hauer & Feld, L.L.P.
                         590 Madison Avenue
                         New York, New York  10022
                         Attn:  L. Kevin O'Mara, Jr., Esq.
                         Telephone:  (212) 872-1000
                         Facsimile:   (212) 872-1002

          Any party may by notice given in accordance with this Section 19 to
the other parties designate another address or person for receipt of notices
hereunder.


                                       10

<PAGE>

     20.  WAIVER. Any term or condition of this Agreement may be waived or
qualified at any time by either Party by a written instrument executed by such
Party. No omission, delay or failure on the part of any Party in exercising any
rights hereunder, and no partial or single exercise hereof, will constitute a
waiver of such rights or of any other rights hereunder.

     21.  MODIFICATIONS. This Agreement may be amended, modified or supplemented
only by a written instrument duly executed by both parties which instrument
shall specifically indicate that it is the desire of the parties to amend,
modify or supplement the Agreement.

     22.  GOVERNING LAW. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York, without giving effect to its
conflict of law rules.

     23.  SEVERABILITY. If any provision of this Agreement is ultimately held to
be invalid, illegal or unenforceable, the validity, legality and enforceability
of the remaining provisions hereof shall not in any way be affected or impaired
thereby, unless the absence of the invalidated provision materially adversely
affects the substantive rights of the parties. To the extent permitted by
applicable law, each Party waives any provision of law which renders any
provision hereof invalid, illegal or unenforceable in any respect. In the event
that any provision of this Agreement shall be held to be invalid, illegal or
unenforceable, the parties shall in such an instance use their best efforts to
replace the invalidated provision by a valid, legal and enforceable provision
which, insofar as practical, implements the purposes hereof.

     24.  AFFILIATES. Each of OraVax and PMC shall cause its respective
Controlled Affiliates to comply fully with the provisions of this Agreement to
the extent such provisions specifically relate, or are intended to specifically
relate, to such Controlled Affiliates, as though such Controlled Affiliates were
expressly named as joint obligors hereunder.

     25.  EXECUTION. This Agreement may be executed in several counterparts,
each of which shall be deemed to be an original.

     26.  HEADINGS. The Section headings in this Agreement are solely for the
convenience and reference of the Parties and are not intended to be descriptive
of the entire contents of, or to affect, any of the terms or provisions hereof.

              [The remainder of this page intentionally left blank]






                                       11

<PAGE>

          IN WITNESS WHEREOF, this LICENSE AGREEMENT has been executed by each
of the parties on the date first above written.

                                    ORAVAX, INC.



                                    By:_______________________________________
                                       Name:
                                       Title:



                                    ORAVAX MERIEUX CO.



                                    By:_______________________________________
                                       Name:
                                       Title:

                                    By:_______________________________________
                                       Name:
                                       Title:



<PAGE>


                                                                      ANNEX C TO
                                                                   EXHIBIT 10.10


                      S.N.C. HEPATITIS C LICENSE AGREEMENT

                  This LICENSE AGREEMENT (the "Agreement" or "License") is
entered into as of __________, 1999 by and between MERIEUX ORAVAX S.N.C., a
French SOCIETE EN NOM COLLECTIF, whose registered head office is at 58, avenue
Leclerc, 69007 Lyon, France, ("Licensee") and ORAVAX, INC., a corporation
organized under the laws of the State of Delaware, ("OraVax" or "Licensor").

                               W I T N E S S E T H

                  WHEREAS, Licensor owns or possesses certain proprietary rights
and know-how relating to vaccines for the prevention, treatment or cure of
hepatitis C in humans (the "Field");

                  WHEREAS, Licensee desires to obtain from Licensor, and
Licensor desires to grant to Licensee, a license under Licensor's proprietary
rights and know-how to research, develop, manufacture, market, sell and
distribute Target Products (as defined below);

                  NOW, THEREFORE, in consideration of the mutual promises,
conditions, covenants and undertakings hereinafter set forth, the parties
hereto, intending to be legally bound, hereby agree as follows:

         1. DEFINITIONS.

                  All capitalized terms used in this Agreement and not otherwise
defined herein shall have the meanings set forth in the Master Agreement (as
defined below) and such definitions are incorporated herein by reference.

         1.1 "Affiliate" shall mean, with respect to either OraVax or Licensee,
(i) any Person (including a partnership) of which securities or other ownership
interests representing 50% or more of the equity or 50% or more of the ordinary
voting power are, at the time such determination is being made, owned,
Controlled or held, directly or indirectly, by such Party, or (ii) any other
Person which, at the time such determination is being made, is Controlling,
Controlled by or under common Control with, such Party.

         1.2 "Basic Technology" shall mean the inventions described in the
patents and patent applications set forth on SCHEDULE A attached hereto.

         1.3 "Collaboration" refers to the time period during which the S.N.C.
is in effect.

         1.4 "Control", whether used as a noun or verb, shall mean the
possession, directly or indirectly, of the power to direct, or cause the
direction of, the management or policies of a Person, whether through the
ownership of voting securities, by contract or otherwise



<PAGE>


         1.5 "Improvements" shall mean any Technology which enhances the
effectiveness of or is an improvement upon any aspect of the OraVax Technology,
which is conceived, discovered, actually reduced to practice, obtained by,
licensed (with right to sublicense) or otherwise acquired by one or more of the
Parties and/or one or more of the Partnerships, or by one or more of their
Controlled Affiliates after the date of this Agreement and prior to the
termination of the Collaboration. Improvements shall include, by way of
illustration but not limitation, enhancements in the form of improving the
process for making the Target Products so that they are made in a less expensive
or more expeditious manner, increasing the immunological or therapeutic
effectiveness of the Target Products, discovering additional biological
information as it relates to the expression of the Target Products, discovering
additional substitutions in the Target Products which increase immunological or
therapeutic effectiveness and discovering new applications of the Target
Products in other fields of use.

         1.6 "Independent Improvement" shall mean any Improvement conceived,
discovered, developed, licensed or otherwise acquired after the date of this
Agreement but prior to any termination of the Collaboration, which was
conceived, discovered, developed, licensed (with the right to sublicense) or
otherwise acquired by either Licensee, OraVax or their Controlled Affiliates due
to funding outside of the Programs by such Party or its Controlled Affiliate.

         1.7 "Licensed Technology" shall mean, collectively, the OraVax
Technology and OraVax' Independent Improvements.

         1.8 "Master Agreement" shall mean that certain Master Agreement by and
between PMC and OraVax dated as of March 31, 1995, as amended by that certain
Amendment Agreement dated November 2, 1998 and that certain Amendment Agreement
dated as of the date hereof.

         1.9 "Net Sales" shall mean with respect to sales of the product
concerned for any period for which the applicable calculation is being made, the
gross amount invoiced to customers less (i) returns and allowances, (ii) trade
and/or quantity discounts, (iii) sales, use, value-added, excise taxes and
similar taxes and duties, (iv) an additional amount which would reasonably
approximate the actual cash discounts, if any, given to customers.

         1.10 "OraVax Technology" shall mean the Basic Technology and any other
Technology other than Severable Technology which (i) relates and is useful to
research, development, use and exploitation of Target Products and (ii) is
owned, licensed or otherwise held by OraVax or any of its Controlled Affiliates
at the date of this Agreement with the right to license or sublicense the same
to the Partnerships.

         1.11 "OraVax Technology Agreement" shall mean any agreement or
understanding pursuant to which OraVax has acquired rights to any of the
Licensed Technology.

         1.12 "Partnership(s)" shall mean, collectively, the SNC and the U.S.
Partnership and, individually, either the SNC or the U.S. Partnership.

         1.13 "Person" shall mean any natural person, corporation, firm,
business trust, joint venture, association, organization, company, partnership
or other business entity, or any government, or agency or political subdivision
thereof.



                                       2
<PAGE>


         1.14 "PMC" shall mean Pasteur Merieux Serums & Vaccins S.A., a French
SOCIETE ANONYME, whose registered head office is located at 58, avenue Leclerc,
69007 Lyon, France.

         1.15 "Proprietary Rights" shall mean patent rights (including, but not
limited to, all granted patents and pending patent applications), copyrights,
trade secret rights and similar rights, and licenses and sublicenses under such
rights.

         1.16 "Severable Technology" shall mean any Technology, which (i) is not
Licensed Technology, and (ii) results during the Collaboration from funding
outside the Collaboration and has or was expected to have applications and uses
outside of the Field but (iii) is useful or potentially useful to the research,
development, manufacture, use or exploitation of Target Products. Severable
Technology shall include, by way of illustration but not limitation, adjuvants,
microencapsulation techniques or any innovation allowing a change in the means
of delivery or the addition of another antigen for use against hepatitis C.
Without limiting the generality of the foregoing, the parties agree that []*
constitutes Severable Technology.

         1.17 "SNC" shall mean the SOCIETE EN NOM COLLECTIF established by
OraVax and PMC under French law to pursue the Collaboration outside the United
States.

         1.18 "Sublicensed Affiliate" shall mean, with respect to either OraVax
or Licensee, any Affiliate with an express or implied (e.g., under a
distribution agreement) license or sublicense to research, develop, make, have
made, market, sell, distribute or use Target Products.

         1.19 "Target Product" shall mean any vaccine for the prevention,
treatment or cure of hepatitis C infections in humans; provided, however, that
any product containing one or more antigens for use against indications other
than hepatitis C shall not be a Target Product unless both Parties shall agree
in writing to extend the definition to include such product. In addition, no
product shall be deemed a Target Product unless either (i) such product utilizes
a method, vaccine or composition described in whole or in part in any of the
patents or any of the original patent applications of the pending patent
applications listed in SCHEDULE A attached hereto or (ii) the research,
development, manufacture or use of such product has or will use Technology
described in whole or in part in any of the patents or any of the original
patent applications of the pending patent applications listed in SCHEDULE A
attached hereto. All references in this definition to patents and patent
applications are solely for the purpose of incorporating the descriptions of the
method, vaccine, composition and/ or Technology contained therein and shall not
be deemed to require that a patent shall issue from any pending patent
application or deemed to require that any patent, whether existing or
subsequently issued, shall be valid or enforceable. Any product that is not a
Target Product shall be deemed a Target Product only if during the term of the
Collaboration the Executive Committee determines to extend the definition of
Target Product to such product.

         1.20 "Technology" shall mean:

         (a) the subject matter of any and all relevant patents and/or pending
patent applications, including, but not limited to, the information contained in
such patents and patent applications,


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       3
<PAGE>


any divisions, continuations, and continuations-in-part based thereon, any
patents which may issue therefrom and any reissues, patents of addition or
importation; and

         (b) any and all relevant inventions (whether or not patentable), ideas,
processes, formulas, technical information, trade secrets, developments,
discoveries, data, the subject matter of any and all copyrights, drawings,
techniques, documents, laboratory note books, pre-clinical and clinical case
reports and report forms, scientific and medical reports, models, and know-how,
including by way of example and in no way limiting the foregoing, any biological
materials and chemical compounds including but not limited to structural genes,
genetic sequences, promoters, enhancers, probes, linkage probes, vectors, hosts,
plasmids, peptides, polypeptides, transformed cell lines, transgenic animals,
proteins, biological modifiers, antigens, reagents, hybridomas, antibodies,
toxins, lectins, enzymes, lipids, hormones, viruses, cells or parts of cells,
cell lines, fragments of any of the foregoing, and any other biologically active
material or compound, whether or not occurring naturally or howsoever derived,
modified, conjugated, cross-linked, immobilized, reduced, purified or produced,
whether by recombinant DNA techniques and/or otherwise.

         1.21 "United States" shall mean the United States of America and its
dependent territories and possessions.

         1.22 "US License Agreement" shall mean that certain license agreement
of even date herewith by and between OraVax, Inc., as licensor, and the U.S.
Partnership, as licensee.

         1.23 "U.S. Partnership" shall mean the partnership established by PMC
and OraVax to pursue the Collaboration in the United States.

         2. LICENSE GRANT.

         2.1 ORAVAX LICENSE TO THE SNC. Subject to all of the terms and
limitations of this Agreement, OraVax hereby grants to the SNC, a worldwide
license, except in the United States, under its Proprietary Rights to use the
Licensed Technology in the Field to research, develop, make, have made, market,
sell, distribute and use the Target Products worldwide, except in the United
States. The foregoing license is limited, and may be exercised solely as
provided herein; provided, however, that any such limitation is without
prejudice to the SNC's exercise of any rights it may now hold or hereafter
obtain independently in respect of any Technology other than the Licensed
Technology.

         2.2 UNDERTAKINGS. Except as provided herein, the licensee granted under
Section 2.1 hereof shall be exclusive in the Field. The SNC undertakes that
during the term of the Collaboration it shall commercially exploit its interest
in the Licensed Technology within the Field worldwide, except in the United
States.

         3. COMPENSATION.

         3.1 LICENSE FEE. In consideration of the licenses granted hereunder, 
Licensee shall pay to Licensor a license fee of []* on the later to occur 
of []*

- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       4
<PAGE>


[]*

         3.2 MILESTONE FEES. Licensee shall, with the exception of clause 
(vi) hereof, pay to Licensor the amounts specified below within []* following 
the accomplishment by Licensee, of the corresponding event set forth below 
(each, a "Milestone"):

                             (i)    []*


                           (ii)     []*


                           (iii)    []*


                           (iv)     []*


                           (v)      []*


                           (vi)     []*

         The foregoing amounts shall be paid by Licensee only once.

         3.3 ROYALTIES. Licensee shall pay Licensor a minimum royalty of []*
which shall be payable in any year when the SNC have any sales of Target
Products anywhere in the world (except in the United States), which shall be
paid with reasonable promptness upon receipt of an invoice following the close
of the year concerned.

         3.4 TAXES. Licensee may withhold from any payments due the Licensor
under this Agreement the appropriate withholding taxes, if any, applicable to
such payments. Licensee shall remit the withheld taxes to the appropriate taxing
authorities, and shall provide to Licensor an official certificate of payments
of such taxes or any other documentation and evidence necessary to verify
payment thereof.

         3.5 RECORDS, ACCOUNTING. If the Collaboration is terminated pursuant to
Section 11 hereof, PMC and OraVax and their successors and assigns shall keep
and maintain detailed and accurate books and records with regard to Net Sales,
royalties, payments received from sublicensees and payments due to the other and
the calculation thereof.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       5
<PAGE>


         4. ORAVAX' RETAINED RIGHTS. Except for the license granted to the SNC
under Section 2.1 hereof, and the license granted to the U.S. Partnership
pursuant to the U.S. License Agreement, OraVax retains all right, title and
interest to the Licensed Technology, subject to all the terms, conditions,
limitations and restrictions of this Agreement, the U.S License Agreement and
the Master Agreement. OraVax' retained rights include, but are not limited to,
(a) the right to use the Licensed Technology for research, development and
manufacturing the Target Products in the Field on behalf of the Collaboration,
and (b) the right to use and exploit the Licensed Technology outside the Field.

         5. LIMITED RIGHT TO GRANT SUBLICENSES. During the term of the
Collaboration the SNC shall only be entitled to grant sublicenses to use the
Licensed Technology within the Field for the purposes and benefit of the
Collaboration.

         6. THIRD PARTY AGREEMENTS. The SNC agrees to comply with all terms,
conditions and restrictions applicable to it imposed by the OraVax Technology
Agreements as the same exist as of the date hereof and any agreements with third
parties relating to any OraVax Independent Improvements.

         7. IMPROVEMENTS; DISCLOSURE.

         7.1 INDEPENDENT IMPROVEMENTS. Any and all Proprietary Rights to any
Independent Improvement conceived, discovered, developed, licensed or otherwise
acquired during the term of the Collaboration, shall, as between the Licensee
and OraVax, be owned by the party that expended the funding for the Independent
Improvement. Notwithstanding the foregoing, any OraVax Independent Improvement
during the term of the Collaboration shall automatically be included within the
license granted under Section 2.1 hereof and automatically included in any
sublicenses granted in accordance with this Agreement without any change or
adjustment to the payments due between the parties hereunder.

         7.2 DISCLOSURE. OraVax and the Licensee agree to promptly disclose to
each other any Improvement which either party conceives, discovers, develops,
licenses or otherwise acquires rights to, during the term of the Collaboration;
provided, however, that if OraVax or the Licensee is offered or obtains
something which would otherwise be an Improvement from a third party but which
is subject to restrictions on disclosure and use, then such party shall notify
the other party of the existence and restrictions on the disclosure and use of
the Improvement and shall consult with the other party on a good faith basis as
to whether the parties need to jointly negotiate a license to obtain disclosure
and use of the Improvement for the purposes of the Collaboration; and, provided,
further, that except as set forth in the foregoing proviso, there shall be no
restrictions on the right of the Licensor to receive Improvements hereunder,
including, but not limited to, pursuant to Section 6 above.

         8. SEVERABLE TECHNOLOGY. OraVax and PMC hereby agree that Severable
Technology is not subject to, or included in, any license granted under this
Agreement. Severable Technology shall be owned by the party that conceives,
discovers, develops, licenses or otherwise acquires the same.



                                       6
<PAGE>


         9. CONFIDENTIALITY. The terms of this Agreement and all Licensed
Technology, Improvements, and all other information disclosed pursuant to this
Agreement shall be subject to the provisions of Article 21 of the Master
Agreement.

         10. PATENT MATTERS. Any and all matters relating to patent prosecution
and protection of a party's Proprietary Rights with respect to the Licensed
Technology and Independent Improvements thereto shall be determined in
accordance with Section 7.5 of the Master Agreement.

         11. TERM AND TERMINATION.

         11.1 TERM. The term of this Agreement shall commence on the date hereof
and shall continue until the Partnership is terminated and dissolved as set
forth in the Master Agreement. In the event that the Partnership is dissolved
(i) both OraVax and PMC shall have co-exclusive rights to the Licensed
Technology, (ii) neither PMC nor OraVax shall have the right to grant
sublicenses of the Licensed Technology, and (iii) neither PMC nor OraVax shall
have the right, either on its own or pursuant to any agreement or arrangement
with a third party to manufacture, have manufactured, sell, have sold, market,
develop or distribute a product derived from the Licensed Technology without the
written consent of the other.

         11.2 TERMINATION. This Agreement shall terminate and all rights granted
by Licensor hereunder shall revert to the Licensor in the event that []*

         11.3 INCORPORATION BY REFERENCE AND SURVIVAL. Any accrued rights to
payment and any cause of action or remedies for breach of this Agreement shall
survive termination. Section 7.5 (Patent Matters) and Articles 17 (Arbitration),
18 (Indemnification) and 21 (Confidentiality) of the Master Agreement are hereby
incorporated herein by reference and shall survive for the purposes hereof in
accordance herewith without regard to any termination of the Master Agreement.
Without limiting the generality of the foregoing, the parties agree that this
Agreement constitutes a "Future Agreement" within the meaning of the Master
Agreement.

         11.4 TRANSFER OF TECHNOLOGY ON TERMINATION. Upon termination of this
Agreement, any documents, records, materials or other tangible manifestations of
the Licensed Technology shall be transferred, returned or retained in accordance
with the relevant provisions of the Master Agreement.

         11.5 REMEDIES. Termination is not the sole remedy under this Agreement
and, whether or not termination is effected, all other remedies will remain
available.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.


                                       7
<PAGE>


         12. ARBITRATION. Any and all disputes in relation to any aspect of this
Agreement shall be settled by final and binding arbitration pursuant to
applicable provisions set forth in Article 17 of the Master Agreement.

         13. PROPRIETARY RIGHTS. As of the Effective Time: (a) OraVax or one or
more of its Affiliates owns or has rights to use and exploit all OraVax
Technology; (b) there have been no material claims made against OraVax or any of
its Affiliates asserting the invalidity, unenforceability of, or misuse of, any
of OraVax' Proprietary Rights to the OraVax Technology; (c) neither OraVax nor
any of its Affiliates has received a notice from a third party indicating that
any aspect of the OraVax Technology may conflict with the asserted rights of
others, or otherwise challenging OraVax' rights to use any of the OraVax
Technology; (d) to OraVax' best knowledge, the present use by OraVax or any of
its Affiliates of such OraVax Technology does not violate or infringe in any
material respect any such rights of others or constitute a material breach under
any agreement with a third party; (e) the OraVax Technology Agreements are the
only agreements to which OraVax or any of its Affiliates are a party pursuant to
which payments may be due in respect of OraVax Technology; (f) the agreements
listed and described on Annex A hereto are the only agreements to which OraVax
or any of its Affiliates is a party affecting OraVax' rights to use and exploit
all of the OraVax Technology; (g) OraVax is in full compliance in all material
respects with the terms and conditions of each of the OraVax Technology
Agreements; (h) each of the OraVax Technology Agreements constitutes the valid
and binding obligations of OraVax and each other party thereto and shall be
enforceable against OraVax and, against each other party thereto in accordance
with its terms (subject, however, to any limitations with respect to enforcement
which may be imposed in connection with bankruptcy, insolvency, reorganization,
moratorium or other laws affecting the enforcement of creditors' rights
generally, and except that no representation or warranty is made as to the
availability of any equitable remedy in connection with the enforcement of any
term thereof). None of the rights of OraVax or any of its Affiliates to such
OraVax Technology will be adversely affected by the execution, delivery or
performance of this Agreement. OraVax and its Affiliates have taken all action
reasonably necessary, using its current standard business practices, to protect
such OraVax Technology.

EXCEPT AS SPECIFICALLY PROVIDED FOR IN THIS SECTION 13, ORAVAX DISCLAIMS ALL
WARRANTIES RELATING TO THE LICENSED TECHNOLOGY, EXPRESS OR IMPLIED, INCLUDING,
BUT NOT LIMITED TO, ANY WARRANTIES AGAINST INFRINGEMENT OF THIRD PARTY RIGHTS,
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

         14. CERTAIN COVENANTS RELATING TO ORAVAX TECHNOLOGY. OraVax hereby 
covenants to []* in the event that, at any time or from time to time, the 
amount of any and all royalties and license or other fees which may be 
payable under the OraVax Technology Agreements to the extent that any such 
royalties exceed []* of net sales.

                  OraVax covenants and agrees at all times during the
Collaboration, and thereafter so long as PMC or its Affiliates or successors and
assigns has any rights to any of the OraVax Technology, (i) to take all action
reasonably necessary to protect all of its rights to the OraVax Technology,
including, but not limited to, the OraVax Technology Agreements, (ii) to comply


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



                                       8
<PAGE>


fully with the terms and conditions of each of the OraVax Technology Agreements
(including, but not limited to any royalty or license (or other) fee
obligations) and otherwise maintain such Agreements in full force and effect;
(provided that OraVax shall not be responsible for adverse effects on the OraVax
Technology Agreements to the extent caused, by the actions of PMC or its
Controlled Affiliates or their successors and assigns unless expressly licensed
or authorized by OraVax pursuant to the Master Agreement or any Closing or
Future Agreement); and (iii) to promptly furnish PMC with copies of any and all
written notices OraVax or any of its directors, officers, employees, agents or
representatives may at any time receive in connection with any of the OraVax
Technology Agreements.

         15. INDEMNIFICATION. Each of OraVax and the Licensee shall defend
indemnify and hold harmless the other and their respective Affiliates to the
full extent provided in Article 18 of the Master Agreement.

         16. ASSIGNMENT. The rights and obligations of the parties under this
Agreement may not be assigned or transferred without the prior written consent
of the other.

         17. EXPORT REGULATIONS. The SNC hereby agrees to comply with all export
laws and restrictions and regulations of the Department of Commerce of the
United States or other United States, French or any other country's agency or
authority, and not to knowingly export, or allow the export or re-export of any
Technology, Target Product or any derivative or direct product thereof, in
violation of any such restrictions, laws or regulations, or, without all
required licenses and authorizations to Afghanistan, the People's Republic of
China or any Group Q, S, W, Y or Z country specified in the then current
Supplement No. 1 to Section 770 of the U.S. Export Administration Regulations
(or any successor supplement or regulations).

         18. IMPORT REGULATIONS. This Agreement is subject to all of the United
States', France's (or any other country's, as appropriate) laws and regulations
controlling the import of drugs and biological products, technical data,
laboratory prototypes and other commodities and Technology.

         19. NOTICES.

         Any notice or other communication required or permitted hereunder shall
be in writing and shall be deemed given when so delivered in person, by
overnight courier, by facsimile transmission (with receipt confirmed by
telephone or by automatic transmission report) or two business days after being
sent by registered or certified mail (postage prepaid, return receipt
requested), as follows:




                                       9
<PAGE>


(a)      if to Licensor, to:

                                    OraVax, Inc.
                                    38 Sidney Street
                                    Cambridge, Massachusetts  02139
                                    Attn:  Lance Gordon
                                    Telephone:  (617) 494-1339
                                    Facsimile:  (617) 494-0924

                                    with a copy to:

                                    Palmer & Dodge LLP
                                    One Beacon Street
                                    Boston, Massachusetts 02108
                                    Attn: Michael Lytton, Esq.
                                    Telephone: (617) 573-0100
                                    Facsimile: (617) 227-4420

(b)      if to Licensee, to:

                                    Merieux OraVax S.N.C.
                                    58 avenue Leclerc
                                    69007 Lyon, France
                                    Attn: Gerant

                                    with a copy to:

                                    Pasteur Merieux Serums & Vaccins S.A.
                                    58, avenue Leclerc
                                    69007 Lyon, France
                                    Attn:  Senior Vice President,
                                               Legal and Corporate Affairs and
                                               General Counsel
                                    Telephone: 011.33.4.37.37.77.84
                                    Facsimile: 011.33.4.37.37.70.61

                                    with a copy to:

                                    Akin, Gump, Strauss, Hauer & Feld, L.L.P.
                                    590 Madison Avenue
                                    New York, New York  10022
                                    Attn:  L. Kevin O'Mara, Jr., Esq.
                                    Telephone:  (212) 872-1000
                                    Facsimile:   (212) 872-1002

         Any party may by notice given in accordance with this Section 19 to the
other parties designate another address or person for receipt of notices
hereunder.



                                       10
<PAGE>


         20. WAIVER. Any term or condition of this Agreement may be waived or
qualified at any time by either Party by a written instrument executed by such
Party. No omission, delay or failure on the part of any Party in exercising any
rights hereunder, and no partial or single exercise hereof, will constitute a
waiver of such rights or of any other rights hereunder.

         21. MODIFICATIONS. This Agreement may be amended, modified or
supplemented only by a written instrument duly executed by both parties which
instrument shall specifically indicate that it is the desire of the parties to
amend, modify or supplement the Agreement.

         22. GOVERNING LAW. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York, without giving effect to its
conflict of law rules.

         23. SEVERABILITY. If any provision of this Agreement is ultimately held
to be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions hereof shall not in any way be
affected or impaired thereby, unless the absence of the invalidated provision
materially adversely affects the substantive rights of the parties. To the
extent permitted by applicable law, each Party waives any provision of law which
renders any provision hereof invalid, illegal or unenforceable in any respect.
In the event that any provision of this Agreement shall be held to be invalid,
illegal or unenforceable, the parties shall in such an instance use their best
efforts to replace the invalidated provision by a valid, legal and enforceable
provision which, insofar as practical, implements the purposes hereof.

         24. AFFILIATES. Each of OraVax and PMC shall cause its respective
Controlled Affiliates to comply fully with the provisions of this Agreement to
the extent such provisions specifically relate, or are intended to specifically
relate, to such Controlled Affiliates, as though such Controlled Affiliates were
expressly named as joint obligors hereunder.

         25. EXECUTION. This Agreement may be executed in several counterparts,
each of which shall be deemed to be an original.

         26. HEADINGS. The Section headings in this Agreement are solely for the
convenience and reference of the Parties and are not intended to be descriptive
of the entire contents of, or to affect, any of the terms or provisions hereof.

              [The remainder of this page intentionally left blank]




                                       11
<PAGE>



         IN WITNESS WHEREOF, this LICENSE AGREEMENT has been executed by each of
the parties on the date first above written.

                                            ORAVAX, INC.



                                            By:_________________________________
                                                  Name:
                                                  Title:



                                            MERIEUX ORAVAX S.N.C.



                                            By:_________________________________
                                                  Name:
                                                  Title:

                                            By:_________________________________
                                                  Name:
                                                  Title:

                                            By:_________________________________
                                                  Name:
                                                  Title:



<PAGE>


                                                                      ANNEX D TO
                                                                   EXHIBIT 10.10


                               AMENDMENT AGREEMENT

                  This Amendment Agreement (the "Amendment Agreement") is
entered into as of this ___ day of ________, 1999 by and between:

                  1. PASTEUR MERIEUX Serums & Vaccins S.A., a SOCIETE ANONYME
existing and organized under the laws of France, registered under number RCS
LYON B 349 505 370, whose registered head office is located at 58, avenue
Leclerc, 69007 Lyon, France (hereinafter referred to as "PMC");

AND

                  2. ORAVAX, Inc., a corporation existing and organized under
the laws of the State of Delaware, having its principal place of business at 38
Sidney Street, Cambridge, Massachusetts, United States of America (hereinafter
referred to as "OraVax").

                  Capitalized terms used but not defined herein shall have the
same meanings assigned to them in the Master Agreement dated March 31, 1995 as
amended by that certain Amendment Agreement dated November 2, 1998 (the "Master
Agreement").

                                   WITNESSETH

                  WHEREAS, OraVax and PMC have entered into the Master Agreement
with respect to the development of products for the treatment and/or prevention
of Helicobacter pylori infections; and

                  WHEREAS, the Master Agreement provides that the parties may
extend the scope of the Collaboration to include products for the prevention of
other infections; and

                  WHEREAS, the Executive Committees of each of the Partnerships
have agreed to extend the scope of the Collaboration to include vaccines for the
prevention of Hepatitis C in humans and in connection therewith each of the
Partnerships has entered into license agreements with PMC for certain technology
relating to vaccines for the prevention of Hepatitis C (collectively, the
"Hepatitis C License Agreements"); and

                  WHEREAS, in connection with entering into the Hepatitis C
License Agreements, the parties desire to amend certain terms of the Master
Agreement to include vaccines for the prevention of Hepatitis C within the Field
of the Collaboration;

                  NOW, THEREFORE, in consideration of the mutual promises,
conditions, covenants and undertakings hereinafter set forth, the parties
hereto, intending to be legally bound, hereby agree as follows:



<PAGE>


                  1. Section 1.1 of the Master Agreement is hereby amended to
include vaccines for the prevention of hepatitis C in humans which utilize the
Technology set forth in the Hepatitis C License Agreements within the Field of
the Collaboration.

                  2. The definition of "OraVax Technology" in Section 1.2 of the
Master Agreement shall, for all purposes other than Article 5 of the Master
Agreement, be amended to include the Technology licensed to PMC from OraVax
relating to vaccines for the prevention of Hepatitis C in humans pursuant to
that certain OraVax / PMC Hepatitis C License Agreement dated as of the date
hereof.

                  3. The definition of "Target Products" in Section 1.2 of the
Master Agreement shall be amended to include products for the prevention,
treatment or cure of Hepatitis C in humans which utilizes the Technology
licensed to the Partnerships pursuant to the Hepatitis C License Agreements.

                  4. A new Section 7.3(c) is hereby added which reads in its
entirety as follows:

                  "(c) Notwithstanding the foregoing, the Parties agree that
                  Sections 7.3(a) and 7.3(b) hereof shall not apply to any
                  license given by OraVax to the Partnerships with respect
                  to hepatitis C."

                  5. A new Section 7.7 is hereby added which reads in its
entirety as follows:

                  "7.7 RESEARCH, DEVELOPMENT AND MANUFACTURE OF TARGET PRODUCTS.
                  In the event that the Program Committee determines that []*
                  is useful or necessary for the research, development and/or 
                  manufacture of a Target Product, PMC agrees to research,  
                  develop and/or manufacture such Target Product using such 
                  []* Notwithstanding the foregoing (but subject to the 
                  obligation of PMC to apply such technology at no additional 
                  cost), the Parties agree that []*constitutes Severable
                  Technology."

                  6. Except as expressly amended hereby, the Master Agreement
and all rights and obligations of the parties thereunder, shall remain in full
force and effect. This Amendment Agreement shall not be deemed to be a consent
to any waiver or modification of any other terms or provisions of the Master
Agreement.


- ----------

* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.



<PAGE>


                  IN WITNESS WHEREOF, this Amendment Agreement has been executed
by each of the parties on the date first above written.

PASTEUR MERIEUX Serums & Vaccins S.A.


By:      ___________________________________
         Name:
         Title:



ORAVAX, INC.



By:      ___________________________________
         Name:
         Title:


<PAGE>


                                                                      ANNEX E TO
                                                                   EXHIBIT 10.10



                          MILESTONE DEFERRAL AGREEMENT

         This Milestone Deferral Agreement (the "Milestone Deferral Agreement")
is entered into as of this ____ day of ______, 1999 by and between:

         1. PASTEUR MERIEUX SERUMS & VACCINS S.A., a SOCIETE ANONYME existing
and organized under the laws of France, registered under number RCS LYON B 349
505 370, whose registered head office is located at 58, avenue Leclerc, 69007
Lyon, France (hereinafter referred to as "PMC");

         2. ORAVAX, Inc., a corporation existing and organized under the laws of
the State of Delaware, having its principal place of business at 38 Sidney
Street, Cambridge, Massachusetts, United States of America (hereinafter referred
to as "OraVax");

         3. MERIEUX ORAVAX S.N.C., the SOCIETE EN NOM COLLECTIF established by
OraVax and PMC under French law (hereinafter referred to as "SNC"); and

         4. ORAVAX MERIEUX CO., a general partnership organized under the laws
of Massachusetts (hereinafter referred to as the "U.S. Partnership").

                                   WITNESSETH

         WHEREAS, PMC and OraVax have entered into a license agreement related
to vaccines against dengue viruses effective as of October 1, 1998 (the "Dengue
License");

         WHEREAS, PMC and Peptide Therapeutics Limited ("Limited") have entered
into an agreement effective as of January 22, 1999 (the "Overview Agreement")
under which, among other things, Limited agrees, in accordance with the terms
and conditions thereof, to cause OraVax to enter into this Agreement and certain
license agreements;

         WHEREAS, OraVax JVM, Inc. and Connaught Laboratories have entered into
an amendment effective as of January 22, 1999 to the Facility Agreement dated as
of November 2, 1998 (the "Loan Amendment").

         NOW, THEREFORE, in consideration of the mutual promises, conditions,
covenants and undertakings hereinafter set forth, the parties hereto, intending
to be legally bound, hereby agree as follows:

         1. As used herein, the following terms shall have the following
meanings:

         "Hepatitis C Licenses" means, collectively, the License Agreement
between OraVax and the U.S. Partnership dated as of the date hereof and the
License Agreement between OraVax and SNC dated as of the date hereof.



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         "JEV/TBE License" means the License Agreement between OraVax and PMC
dated as of the date hereof.

         "Master Agreement" means the Master Agreement between OraVax and PMC
dated March 31, 1995 and amended November 2, 1998 and further amended as of the
date hereof.

         2. As consideration for and an inducement to PMC to enter into the
JEV/TBE License and for SNC and the U.S. Partnership to enter into the Hepatitis
C Licenses and in consideration of the research funding, milestone payments and
royalties to be received by OraVax under the Dengue License, the JEV/TBE
License, the Hepatitis C Licenses and the Master Agreement and the loan deferral
under the Loan Amendment, the parties hereby agree that PMC or SNC or the U.S.
Partnership (as the case may be) may, at its sole option and on written notice
to OraVax, defer in the aggregate up to three million United States dollars
($3,000,000) (the "Deferral Credit") in milestone payments payable to OraVax
under the Master Agreement, Dengue License, JEV/TBE License and Hepatitis C
Licenses. The amount of any milestone payment in respect of any licensed product
under any such Agreement deferred by PMC or SNC or the U.S. Partnership (the
"Product Deferral") shall be added to the last four remaining milestones
relating to such licensed product at a rate of []* of the Product
Deferral per milestone.

         3. Except as expressly provided hereunder, the Dengue License,
Hepatitis C Licenses, JEV/TBE License, Master Agreement and Loan Amendment and
all rights and obligations of the parties thereunder, shall remain in full force
and effect.

                  [Remainder of page intentionally left blank]



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* This portion of the Exhibit has been omitted pursuant to a request for 
Confidential Treatment under Rule 406 of the Securities Act of 1933, as 
amended.  The Complete Exhibit, including the portions for which confidential 
treatment has been requested, has been filed separately with the Securities 
and Exchange Commission.




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         IN WITNESS WHEREOF, this Milestone Deferral Agreement has been executed
by each of the parties on the date first above written.

PASTEUR MERIEUX Serums & Vaccins S.A.


By: ___________________________________
Name:
Title:

ORAVAX, Inc.


By: ___________________________________
Name:
Title:

MERIEUX ORAVAX S.N.C.


By: ___________________________________
Name:
Title:


By: ___________________________________
Name:
Title:

ORAVAX MERIEUX CO.


By: ___________________________________
Name:
Title:


By: ___________________________________
Name:
Title:



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