PROGENICS PHARMACEUTICALS INC
S-1/A, 1997-10-09
PHARMACEUTICAL PREPARATIONS
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<PAGE>
   
    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 9, 1997
    
 
                                                      REGISTRATION NO. 333-13627
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
 
   
                                AMENDMENT NO. 7
                                       TO
                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
    
 
                        PROGENICS PHARMACEUTICALS, INC.
             (Exact name of registrant as specified in its charter)
 
<TABLE>
<S>                              <C>                            <C>
           DELAWARE                          2834                  13-3379479
 (State or other jurisdiction    (Primary Standard Industrial   (I.R.S. Employer
              of                 Classification Code Number)     Identification
incorporation or organization)                                        No.)
</TABLE>
 
                          777 OLD SAW MILL RIVER ROAD
                           TARRYTOWN, NEW YORK 10591
                                 (914) 789-2800
       (Address, including zip code and telephone number, including area
               code, of registrant's principal executive offices)
 
                          PAUL J. MADDON, M.D., PH.D.
          CHAIRMAN OF THE BOARD, CHIEF EXECUTIVE OFFICER AND PRESIDENT
                        PROGENICS PHARMACEUTICALS, INC.
                          777 OLD SAW MILL RIVER ROAD
                           TARRYTOWN, NEW YORK 10591
                                 (914) 789-2800
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
 
                           --------------------------
 
COPIES OF ALL COMMUNICATIONS, INCLUDING ALL COMMUNICATIONS SENT TO THE AGENT FOR
                          SERVICE, SHOULD BE SENT TO:
 
   
        DONALD J. MURRAY, ESQ.                    DAVID E. REDLICK, ESQ.
         DEWEY BALLANTINE LLP                       HALE AND DORR LLP
     1301 AVENUE OF THE AMERICAS                     60 STATE STREET
       NEW YORK, NEW YORK 10019                BOSTON, MASSACHUSETTS 02109
            (212) 259-8000                            (617) 526-6000
 
                           --------------------------
    
 
        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
As soon as practicable after the effective date of this Registration Statement.
 
                           --------------------------
 
    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box: / /
 
    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: / /
 
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box: / /
 
                           --------------------------
 
    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 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(A),
MAY DETERMINE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
                                    PART II
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
    The following is an itemized statement of the estimated amounts of all
expenses payable by the Registrant in connection with the registration of the
Common Stock offered hereby, other than underwriting discounts and commissions:
 
   
<TABLE>
<S>                                                               <C>
Registration Fee--Securities and Exchange Commission............  $   9,061
NASD Filing Fee.................................................      3,490
Blue Sky fees and expenses......................................     20,000
Accountants' fees and expenses..................................      *
Legal fees and expenses.........................................      *
Printing and engraving expenses.................................      *
Transfer agent and registrar fees...............................      *
Miscellaneous...................................................      *
                                                                  ---------
            Total...............................................  $ 750,000
                                                                  ---------
                                                                  ---------
</TABLE>
    
 
- ------------------------
 
   
*   To be completed by amendment.
    
 
ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
    Section 145(a) of the General Corporation Law of the State of Delaware (the
"DGCL") provides that a Delaware corporation may indemnify any person who was or
is a party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the corporation) by
reason of the fact that he is or was a director, officer, employee or agent of
the corporation or is or was serving at the request of the corporation as a
director, officer, employee or agent of another corporation or enterprise,
against expenses, judgments, fines and amounts paid in settlement actually and
reasonably incurred by him in connection with such action, suit or proceeding if
he acted in good faith and in a manner he reasonably believed to be in or not
opposed to the best interests of the corporation, and, with respect to any
criminal action or proceeding, had no cause to believe his conduct was unlawful.
 
    Section 145(b) of the DGCL provides that a Delaware corporation may
indemnify any person who was or is a party or is threatened to be made a party
to any threatened, pending or completed action or suit by or in the right of the
corporation to procure a judgment in its favor by reason of the fact that such
person acted in any of the capacities set forth above, against expenses actually
and reasonably incurred by him in connection with the defense or settlement of
such action or suit if he acted under similar standards, except that no
indemnification may be made in respect of any claim, issue or matter as to which
such person shall have been adjudged to be liable to the corporation unless and
only to the extent that the court in which such action or suit was brought shall
determine that despite the adjudication of liability, such person is fairly and
reasonably entitled to be indemnified for such expenses which the court shall
deem proper.
 
    Section 145 of the DGCL further provides that to the extent a director or
officer of a corporation has been successful in the defense of any action, suit
or proceeding referred to in subsections (a) and (b) or in the defense of any
claim, issue, or matter therein, he shall be indemnified against expenses
actually and reasonably incurred by him in connection therewith; that
indemnification provided for by Section 145 shall not be deemed exclusive of any
other rights to which the indemnified party may be entitled; and that the
corporation may purchase and maintain insurance on behalf of a director or
officer of the corporation against any liability asserted against him or
incurred by him in any such capacity or arising out of his status
 
                                      II-1
<PAGE>
as such whether or not the corporation would have the power to indemnify him
against such liabilities under such Section 145.
 
    Section 102(b)(7) of the DGCL provides that a corporation in its original
certificate of incorporation or an amendment thereto validly approved by
stockholders may eliminate or limit personal liability of members of its board
of directors or governing body for breach of a director's fiduciary duty.
However, no such provision may eliminate or limit the liability of a director
for breaching his duty of loyalty, failing to act in good faith, engaging in
intentional misconduct or knowingly violating a law, paying a dividend or
approving a stock repurchase which was illegal, or obtaining an improper
personal benefit. A provision of this type has no effect on the availability of
equitable remedies, such as injunction or rescission, for breach of fiduciary
duty. The Company's Restated Certificate of Incorporation contains such a
provision.
 
    The Company's Certificate of Incorporation and By-Laws provide that the
Company shall indemnify officers and directors, and to the extent authorized by
the Board of Directors, employees and agents of the Company, to the full extent
permitted by and in the manner permissible under the laws of the State of
Delaware. In addition, the By-Laws permit the Board of Directors to authorize
the Company to purchase and maintain insurance against any liability asserted
against any director, officer, employee or agent of the Company arising out of
his capacity as such.
 
    The Company has entered into Indemnification Agreements with each of its
officers and directors, pursuant to which the Company has agreed to indemnify
and advance expenses to such officers and directors to the fullest extent
permitted by applicable law.
 
    The Company has obtained an insurance policy providing coverage for certain
liabilities of its officers and directors.
 
ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES
 
   
    During the past three years, the Registrant has issued securities to a
limited number of persons, as described below. No underwriter or underwriting
discounts or commissions were involved. There was no public offering in any such
transaction and the Company believes that each transaction was exempt from the
registration requirements of the Securities Act of 1933, as amended (the
"Securities Act"), by reason of Section 4(2) thereof based on the private nature
of the transactions and the sophistication of the purchasers, all of whom had
access to information concerning the Registrant and acquired the securities for
investment and not with a view to the distribution thereof.
    
 
    From January 1993 through August 1993, the registrant issued a total of
272,270 shares of Series B Preferred Stock, $.001 par value per share, and
warrants to purchase 272,270 shares of Series B Preferred Stock, to 33
individuals and entities of whom two entities are affiliates of the Company, one
individual is a director and the rest are accredited investors for an aggregate
purchase price of $1,089,080 in cash.
 
    In September 1993 and October 1993, the registrant issued a total of 562,500
shares of Series B Preferred Stock, and warrants to purchase 562,500 shares of
Series B Preferred Stock, to three entities of whom two entities are affiliates
of the Company and the remaining entity is an accredited investor for an
aggregate purchase price of $2,250,000.
 
    In February 1994, the registrant issued a total of 719,310 shares of Series
B Preferred Stock to 22 individuals and entities of whom one entity is an
affiliate of the Company, one individual is a director and the remaining
individuals and entities are accredited investors for an aggregate purchase
price of $3,596,550 in cash.
 
    In November 1995 and December 1995, the registrant issued a total of 424,184
shares of Series C Preferred Stock, $.001 par value per share, and warrants to
purchase 106,046 shares of Series C Preferred Stock, to seven individuals and
entities of whom one individual is a director, two entities are affiliated with
a director of the Company and the remaining individuals and entities are
accredited investors for an
 
                                      II-2
<PAGE>
aggregate purchase price of $897,249 in cash and conversion of a note payable in
the principal amount of $1,200,000 plus accrued interest thereon of $23,671.
 
   
    In August 1995, the registrant issued 45,000 shares of Common Stock, $.0013
par value per share, to one entity which is a licensor as partial consideration
for a license agreement.
    
 
    In January 1996 and February 1996, the registrant issued a total of 964,812
shares of Series C Preferred Stock, and warrants to purchase 241,203 shares of
Series C Preferred Stock, to 52 individuals and entities of whom two entities
are affiliates of the Company, two individuals are directors and the remaining
individuals and entities are accredited investors for an aggregate purchase
price of $4,824,060 in cash.
 
   
    From January 1, 1993 to August 31, 1997, the Company issued options to
purchase 1,613,738 shares of Common Stock (of which options to purchase 80,156
shares of Common Stock subsequently have been cancelled) to employees and
consultants of the Company pursuant to the 1989 Option Plan, the 1993 Option
Plan and the 1993 Executive Option Plan. None of such options has been
exercised.
    
 
   
    In July 1997 the Registrant issued 120,000 shares of Common Stock to one
entity as consideration in part for such entity consenting to certain agreements
entered into by the Registrant with another entity.
    
 
   
    In March, June and July of 1997, the Registrant issued to two entities
warrants to purchase in the aggregate 70,000 shares of Common Stock at an
exercise price of $3.00 (subject to adjustment in the event certain liquidity
events occur prior to December 31, 1997).
    
 
   
    In January 1997 one person exercised options granted to such person in April
1989 to purchase 27,000 shares of Common Stock at an exercise price of $1.33 per
share.
    
 
ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
    (a) Exhibits
 
   
<TABLE>
<C>        <S>
    **1.1  --Revised Form of Underwriting Agreement
 
    **3.1  --Certificate of Incorporation, as amended, of the Registrant
 
    **3.2  --By-Laws of the Registrant
 
    **4.1  --Specimen Certificate for Common Stock, $.0013 par value per share, of the
             Registrant
 
 TRIANGLE 5.1 --Opinion of Dewey Ballantine LLP
 
   **10.1  --Form of Registration Rights Agreement
 
   **10.2  --1989 Non-Qualified Stock Option Plan
 
   **10.3  --1993 Stock Option Plan as amended
 
   **10.4  --1993 Executive Stock Option Plan
 
   **10.5  --Amended 1996 Stock Incentive Plan
 
   **10.6  --Form of Indemnification Agreement
 
   **10.7  --Employment Agreement dated December 15, 1993 between the Registrant and Dr. Paul
             J. Maddon
 
   **10.8  --Letter dated August 25, 1994 between the Registrant and Dr. Robert J. Israel
 
   **10.9  --Sublease dated July 13, 1988 between the Registrant and Union Carbide Corporation
 
 **+10.10  --gp120 Supply Agreement dated July 19, 1995 between the Registrant and E. I.
             DuPont De Nemours and Company, as amended, October 27, 1995
 
 **+10.11  --sCD4 Supply Agreement dated June 27, 1995 between the Registrant and E. I. DuPont
             De Nemours and Company
 
 **+10.12  --Supply Agreement dated February 8, 1996 between the Registrant and Intracel
             Corporation
</TABLE>
    
 
                                      II-3
<PAGE>
   
<TABLE>
<C>        <S>
 **+10.13  --License Agreement dated November 17, 1994 between the Registrant and
             Sloan-Kettering Institute for Cancer Research
 
 **+10.14  --Clinical Trial Agreement dated December 12, 1994 between the Registrant and
             Sloan-Kettering Institute for Cancer Research
 
 **+10.15  --QS-21 License and Supply Agreement dated August 31, 1995 between the Registrant
             and Cambridge Biotech Corporation (now known as Aquila Biopharmaceuticals, Inc.)
 
 **+10.16  --gp120 Sublicense Agreement dated March 17, 1995 between the Registrant and
             Cambridge Biotech Corporation (now known as Aquila Biopharmaceuticals, Inc.)
 
 **+10.17  --Cooperative Research and Development Agreement dated February 25, 1993 between
             the Registrant and the Centers for Disease Control and Prevention
 
 **+10.18  --License Agreement dated March 1, 1989, as amended by a Letter Agreement dated
             March 1, 1989 and as amended by a Letter Agreement dated October 22, 1996 between
             the Registrant and the Trustees of Columbia University
 
 **+10.19  --License Agreement dated June 25, 1996 between the Registrant and The Regents of
             the University of California
 
 **+10.20  --KLH Supply Agreement dated July 1, 1996 between the Registrant and PerImmune,
             Inc.
 
 **+10.21  --sCD4 Supply Agreement dated November 3, 1993 between the Registrant and E.I.
             DuPont De Nemours and Company
 
  **10.22  --Lease dated June 30, 1994 between the Registrant and Keren Limited Partnership
 
  ++10.23  --Joint Development and Master License Agreement dated as of April 15, 1997 between
             Bristol-Myers Squibb Company and the Registrant
 
  ++10.24  --Sublicense Agreement with respect to the Sloan-Kettering License Agreement dated
             as of April 15, 1997 between Bristol-Myers Squibb Company and the Registrant
 
  ++10.25  --Sublicense Agreement with respect to The Regents' License Agreement dated April
             15, 1997 between Bristol-Myers Squibb Company and the Registrant
 
  ++10.26  --Sublicense Agreement with respect to Aquila Biopharmaceuticals, Inc. License and
             Supply Agreement dated April 15, 1997 between Bristol-Myers Squibb Company and
             the Registrant
 
  ++10.27  --Letter agreement dated as of April 15, 1997 among Bristol-Myers Squibb Company,
             Registrant and the Sloan-Kettering Institute for Cancer Research
 
   +10.28  --Letter agreement dated as of April 15, 1997 among Bristol-Myers Squibb Company,
             Registrant and The Regents of the University of California
 
  ++10.29  --Letter agreement dated as of April 15, 1997 among Bristol-Myers Squibb Company,
             Registrant and Aquila Biopharmaceuticals, Inc.
 
   +10.30  --Form of Warrant to purchase Series C Preferred Stock
 
   +10.31  --Form of Warrant issued to Tudor BVI Futures, Ltd. and Tudor Global Trading LLC
 
   **11.1  --Statement of computation of loss per share for the years ended December 31, 1994,
             1995 and 1996
 
   **11.2  --Statement of computation of loss per share for the six months ended June 30, 1996
             and 1997
 
   **11.3  --Pro forma statement of computation of loss per share
 
   **23.1  --Consent of Coopers & Lybrand L.L.P.
 
 TRIANGLE 23.2 --Consent of Dewey Ballantine LLP (contained in Exhibit 5.1)
 
   **24.1  --Power of Attorney (included on page II-5)
 
   **27.1  --Financial Data Schedule
</TABLE>
    
 
- ------------------------
 
**  Previously filed.
 
                                      II-4
<PAGE>
   
+  Confidential treatment requested as to certain portions, which portions are
    omitted and filed separately with the Commission.
    
 
   
+   Filed herewith.
    
 
   
 TRIANGLE  To be filed by amendment.
    
 
    (b) Financial Statement Schedules
 
    All schedules have been omitted because they are not required or because the
required information is given in the Financial Statements or Notes thereto.
 
ITEM 17. UNDERTAKINGS
 
    The undersigned Registrant hereby undertakes to provide to the underwriters,
at the closing specified in the underwriting agreement, certificates in such
denominations and registered in such names as required by the underwriters to
permit prompt delivery to each purchaser.
 
    Insofar as indemnification for liabilities arising under the Securities Act
of 1933 may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other 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, 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 Act and will be governed by the final adjudication of
such issue.
 
    The undersigned Registrant hereby undertakes that:
 
        (1) For purposes of determining any liability under the Securities Act
    of 1933, the information omitted from the form of prospectus filed as part
    of this registration statement in reliance upon Rule 430A and contained in a
    form of prospectus filed by the Registrant pursuant to Rule 424(b)(1) or (4)
    or 497(h) under the Securities Act shall be deemed to be part of this
    registration statement as of the time it was declared effective.
 
        (2) For the purpose of determining any liability under the Securities
    Act of 1933, each post-effective amendment that contains a form of
    prospectus 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.
 
                                      II-5
<PAGE>
                                   SIGNATURES
 
   
    Pursuant to the requirements of the Securities Act of 1933, the Registrant
has duly caused this Amendment to the Registration Statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of Tarrytown,
State of New York, on October 9, 1997.
    
 
                                PROGENICS PHARMACEUTICALS, INC.
 
                                BY:        /s/ PAUL J. MADDON, M.D., PH.D
                                     -----------------------------------------
                                            Paul J. Maddon, M.D., Ph.D.
                                               Chairman of the Board,
                                       Chief Executive Officer and President
 
                               POWER OF ATTORNEY
 
   
    Pursuant to the requirements of the Securities Act of 1933, as amended, this
Amendment to the Registration Statement has been signed by the following persons
on October 9, 1997 in the capacities indicated:
    
 
   
          SIGNATURE                        TITLE                    DATE
- ------------------------------  ---------------------------  -------------------
 
                                Chairman of the Board,
              *                   Chief Executive Officer
- ------------------------------    and President (principal     October 9, 1997
 Paul J. Maddon, M.D., Ph.D.      executive officer)
 
                                Vice President, Finance and
              *                   Operations, Treasurer
- ------------------------------    (principal accounting and    October 9, 1997
      Robert A. McKinney          financial officer)
 
              *                 Director
- ------------------------------                                 October 9, 1997
       Charles A. Baker
 
              *                 Director
- ------------------------------                                 October 9, 1997
        Mark F. Dalton
 
              *                 Director
- ------------------------------                                 October 9, 1997
    Stephen P. Goff, Ph.D.
 
              *                 Director
- ------------------------------                                 October 9, 1997
    Elizabeth M. Greetham
 
    
 
                                      II-6
<PAGE>
 
   
          SIGNATURE                        TITLE                    DATE
- ------------------------------  ---------------------------  -------------------
 
              *                 Director
- ------------------------------                                 October 9, 1997
       Paul F. Jacobson
 
              *                 Director
- ------------------------------
  David A. Scheinberg, M.D.,                                   October 9, 1997
            Ph.D.
 
    
 
*By:                    /s/ ROBERT A. MCKINNEY
            -------------------------------------------
                         Robert A. McKinney
                       (As Attorney-in-Fact)
 
                                      II-7
<PAGE>
                               INDEX TO EXHIBITS
 
   
<TABLE>
<CAPTION>
   EXHIBITS                                              DESCRIPTION                                              PAGE
- --------------  ----------------------------------------------------------------------------------------------  ---------
<C>             <S>                                                                                             <C>
         **1.1  --Revised Form of Underwriting Agreement
 
         **3.1  --Certificate of Incorporation, as amended, of the Registrant
 
         **3.2  --By-Laws of the Registrant
 
         **4.1  --Specimen Certificate for Common Stock, $.0013 par value per share, of the Registrant
 
  TRIANGLE 5.1  --Opinion of Dewey Ballantine LLP
 
        **10.1  --Form of Registration Rights Agreement
 
        **10.2  --1989 Non-Qualified Stock Option Plan
 
        **10.3  --1993 Stock Option Plan as amended
 
        **10.4  --1993 Executive Stock Option Plan
 
        **10.5  --Amended 1996 Stock Incentive Plan
 
        **10.6  --Form of Indemnification Agreement
 
        **10.7  --Employment Agreement dated December 15, 1993 between the Registrant and Dr. Paul J. Maddon
 
        **10.8  --Letter dated August 25, 1994 between the Registrant and Dr. Robert J. Israel
 
        **10.9  --Sublease dated July 13, 1988 between the Registrant and Union Carbide Corporation
 
      **+10.10  --gp120 Supply Agreement dated July 19, 1995 between the Registrant and E. I. DuPont De
                 Nemours and Company, as amended, October 27, 1995
 
      **+10.11  --sCD4 Supply Agreement dated June 27, 1995 between the Registrant and E. I. DuPont De Nemours
                 and Company
 
      **+10.12  --Supply Agreement dated February 8, 1996 between the Registrant and Intracel Corporation
 
      **+10.13  --License Agreement dated November 17, 1994 between the Registrant and Sloan-Kettering
                 Institute for Cancer Research
 
      **+10.14  --Clinical Trial Agreement dated December 12, 1994 between the Registrant and Sloan-Kettering
                 Institute for Cancer Research
 
      **+10.15  --QS-21 License and Supply Agreement dated August 31, 1995 between the Registrant and
                 Cambridge Biotech Corporation (now known as Aquila Biopharmaceuticals, Inc.)
 
      **+10.16  --gp120 Sublicense Agreement dated March 17, 1995 between the Registrant and Cambridge Biotech
                 Corporation (now known as Aquila Biopharmaceuticals, Inc.)
 
      **+10.17  --Cooperative Research and Development Agreement dated February 25, 1993 between the
                 Registrant and the Centers for Disease Control and Prevention
 
      **+10.18  --License Agreement dated March 1, 1989, as amended by a Letter Agreement dated March 1, 1989
                 and as amended by a Letter Agreement dated October 22, 1996 between the Registrant and the
                 Trustees of Columbia University
 
      **+10.19  --License Agreement dated June 25, 1996 between the Registrant and The Regents of the
                 University of California
 
      **+10.20  --KLH Supply Agreement dated July 1, 1996 between the Registrant and PerImmune, Inc.
 
      **+10.21  --sCD4 Supply Agreement dated November 3, 1993 between the Registrant and E.I. DuPont De
                 Nemours and Company
 
       **10.22  --Lease dated June 30, 1994 between the Registrant and Keren Limited Partnership
 
       ++10.23  --Joint Development and Master License Agreement dated as of April 15, 1997 between
                 Bristol-Myers Squibb Company and the Registrant
</TABLE>
    
<PAGE>
   
<TABLE>
<C>             <S>                                                                                             <C>
       ++10.24  --Sublicense Agreement with respect to the Sloan-Kettering License Agreement dated as of April
                 15, 1997 between Bristol-Myers Squibb Company and the Registrant
 
       ++10.25  --Sublicense Agreement with respect to The Regents' License Agreement dated April 15, 1997
                 between Bristol-Myers Squibb Company and the Registrant
 
       ++10.26  --Sublicense Agreement with respect to Aquila Biopharmaceuticals, Inc. License and Supply
                 Agreement dated April 15, 1997 between Bristol-Myers Squibb Company and the Registrant
 
       ++10.27  --Letter agreement dated as of April 15, 1997 among Bristol-Myers Squibb Company, Registrant
                 and the Sloan-Kettering Institute for Cancer Research
 
        +10.28  --Letter agreement dated as of April 15, 1997 among Bristol-Myers Squibb Company, Registrant
                 and The Regents of the University of California
 
       ++10.29  --Letter agreement dated as of April 15, 1997 among Bristol-Myers Squibb Company, Registrant
                 and Aquila Biopharmaceuticals, Inc.
 
        +10.30  --Form of Warrant to purchase Series C Preferred Stock
 
        +10.31  --Form of Warrant issued to Tudor BVI Futures, Ltd. and Tudor Global Trading LLC
 
        **11.1  --Statement of computation of loss per share for the years ended December 31, 1994, 1995 and
                 1996
 
        **11.2  --Statement of computation of loss per share for the six months ended June 30, 1996 and 1997
 
        **11.3  --Pro forma statement of computation of loss per share
 
        **23.1  --Consent of Coopers & Lybrand L.L.P.
 
 TRIANGLE 23.2  --Consent of Dewey Ballantine LLP (contained in Exhibit 5.1)
 
        **24.1  --Power of Attorney (included on page II-5)
 
        **27.1  --Financial Data Schedule
</TABLE>
    
 
- ------------------------
 
**  Previously filed.
 
   
+  Confidential treatment requested as to certain portions, which portions are
    omitted and filed separately with the Commission.
    
 
   
+   Filed herewith.
    
 
   
 TRIANGLE  To be filed by amendment.
    

<PAGE>

                                                                   Exhibit 10.23


                                JOINT DEVELOPMENT
                                       AND
                            MASTER LICENSE AGREEMENT

                                     BETWEEN

                        PROGENICS PHARMACEUTICALS, INC.

                                      AND

                          BRISTOL-MYERS SQUIBB COMPANY

                                  DATED AS OF

                                 APRIL 15, 1997


[Note: Certain portions of this document have been marked "[XXX]" to 
indicate that confidentiality has been requested for this information. The 
confidential portions have been omitted and filed separately with the 
Securities and Exchange Commission.]

<PAGE>

                              TABLE OF CONTENTS

                                                                            Page
                                                                            ----

1.   DEFINITIONS .........................................................    2
       1.1       "Adjuvant ...............................................    2
       1.2       "Affiliate" .............................................    2
       1.3       "Aquila Field of Use" ...................................    2
       1.4       "Aquila Knowhow" ........................................    2
       1.5       "Aquila Licensed Patent Rights" .........................    2
       1.6       "Aquila Licensed Product" ...............................    2
       1.7       "Aquila Sublicense Agreement" ...........................    2
       1.8       "BCG" ...................................................    2
       1.9       "BMS Clinical Trials" ...................................    2
       1.10      "Clinical Trial Agreements" .............................    3
       1.11      "Compound" ..............................................    3
       1.12      "Confidential Information" ..............................    3
       1.13      "Derivative" ............................................    3
       1.14      "Effective Date" ........................................    3
       1.15      "FDA" ...................................................    3
       1.16      "First Commercial Sale" .................................    4
       1.17      "GD2" ...................................................    4
       1.18      "Generic Product" .......................................    4
       1.19      "GM2" ...................................................    4
       1.20      "GMK Development Completion" ............................    4
       1.21      "GMK Vaccine" ...........................................    4
       1.22      "Joint Steering Committee" ..............................    4
       1.23      "KLH" ...................................................    4
       1.24      "Licensed Patents" ......................................    4
       1.25      "Licensed Products" .....................................    4
       1.26      "Licensed Technical Information" ........................    4
       1.27      "MGV Development Completion" ............................    4
       1.28      "MGV Vaccine" ...........................................    5
       1.29      "Net Sales" .............................................    5
       1.30      "Party" .................................................    5
       1.31      "Person" ................................................    5
       1.32      "PROGENICS Clinical Trials" .............................    5
       1.33      "PROGENICS License" .....................................    5
       1.34      "PROGENICS Technical Information" .......................    5
       1.35      "QS-2l" .................................................    5
       1.36      "Regents' Field" ........................................    6
       1.37      "Regents' Method" .......................................    6
       1.38      "Regents' Patent Rights" ................................    6
       1.39      "Regents' Products" .....................................    6
       1.40      "S-K Field" .............................................    6
       1.41      "S-K Licensed Patents" ..................................    6
       1.42      "S-K Products" ..........................................    6
       1.43      "S-K Technical Information" .............................    6
       1.44      "Sloan-Kettering Sublicense Agreement" ..................    6
       1.45      "Sub-sublicensee" .......................................    6
       1.46      "Territory" .............................................    6
       1.47      "The Regents Sublicense Agreement" ......................    6


                                     (i)
<PAGE>

                          TABLE OF CONTENTS (continued)

                                                                            Page
                                                                            ----

       1.48      "Third Party" ...........................................    6
       1.49      "Valid Claim" ...........................................    6

2.   REPRESENTATIONS AND WARRANTIES ......................................    6
       2.1       Representations and Warranties of Both Parties ..........    6
       2.2       Representations and Warranties of PROGENICS .............    7

3.   JOINT STEERING COMMITTEE ............................................    8
       3.1       Creation ................................................    8
       3.2       Purpose .................................................    8
       3.3       Meetings ................................................    8
       3.4       Deadlock ................................................    9

4.   PRODUCT DEVELOPMENT .................................................    9
       4.1       Current Research Collaborations .........................    9
       4.2       Continued  Development  of  Licensed Products by
                 PROGENICS ...............................................   10
       4.3       Conduct of Development by PROGENICS .....................   12
       4.4       Delivery of Data; Transfer of IND .......................   12
       4.5       Development by BMS ......................................   13
       4.6       BMS Diligence Milestones ................................   14
       4.7       Conduct of BMS Clinical Trials ..........................   15
       4.8       Records .................................................   16
       4.9       Pricing Matters .........................................   16
       4.10      Adverse Reaction Reporting ..............................   16

5.   GRANT OF RIGHTS .....................................................   17
       5.1       Grant of License Under this Agreement ...................   17
       5.2       Grant of Sublicense Under Sloan-Kettering License
                 Agreement ...............................................   18
       5.3       Grant  of  Sublicense  Under  The  Regents License
                 Agreement ...............................................   18
       5.4       Grant of Sublicense Under Aquila License and Supply
                 Agreement ...............................................   18
       5.5       Sublicense Rights .......................................   18
       5.6       Reservation of Rights by PROGENICS ......................   19

6.   UP-FRONT; MILESTONE AND ROYALTY PAYMENTS ............................   19
       6.1       Reimbursement of Expenses ...............................   19
       6.2       Up-front Fee ............................................   19
       6.3       Milestone Payments Regarding GMK Vaccine ................   20
       6.4       Milestone Payments Regarding MGV Vaccine ................   21
       6.5       Royalty Payments ........................................   22
       6.6       Reductions to Royalties .................................   26
       6.7       Obligation to Pay Royalties .............................   26


                                      (ii)
<PAGE>

                          TABLE OF CONTENTS (continued)

                                                                            Page
                                                                            ----

7.   PAYMENTS AND REPORTS ................................................   27
       7.1       Reports; Payments .......................................   27
       7.2       Mode of Payment; Taxes ..................................   27
       7.3       Records Retention .......................................   27
       7.4       Audit Request ...........................................   27
       7.5       Cost of Audit ...........................................   28
       7.6       No Non-Monetary Consideration for Sales .................   28
              
8.     INDEMNIFICATION; INFRINGEMENT .....................................   28
       8.1       Indemnification .........................................   28
       8.2       Conditions to Indemnification ...........................   29
       8.3       Infringement Action by Third Parties ....................   30

9.   CONFIDENTIALITY AND NON-USE .........................................   30
       9.1       Notification ............................................   30
       9.2       Review of Proposed Publications .........................   31
       9.3       Confidentiality and Non-use; Exceptions .................   31
       9.4       Authorized Disclosure ...................................   31
              
10.  TERMINATION .........................................................   32
      10.1       Term ....................................................   32
      10.2       Breach ..................................................   32
      10.3       Termination by BMS ......................................   33
      10.4       Effect of Termination ...................................   34
      10.5       Right to Sell Stock on Hand .............................   38
      10.6       Termination of Sublicenses ..............................   38
      10.7       Accrued Rights, Surviving Obligations ...................   38
               
11.  MISCELLANEOUS .......................................................   38
      11.1       Relationship of Parties .................................   38
      11.2       Force Majeure ...........................................   38
      11.3       Assignment ..............................................   39
      11.4       Further Actions .........................................   39
      11.5       Notice ..................................................   39
      11.6       Use of Name .............................................   40
      11.7       Public Announcements ....................................   40
      11.8       Costs and Expenses ......................................   40
      11.9       Waiver ..................................................   40
      11.10      Inconsistency ...........................................   41
      11.11      Compliance with Law .....................................   41
      11.12      Severability ............................................   41
      11.13      Amendment ...............................................   41
      11.14      Governing Law ...........................................   41
      11.15      Arbitration .............................................   41
      11.16      Entire Agreement ........................................   41
      11.17      Counterparts ............................................   42
      11.18      Descriptive Headings ....................................   42


                                      (iii)
<PAGE>

                               LIST OF EXHIBITS

EXHIBIT A               List of Licensed Patents
EXHIBIT B               Description of PROGENICS Clinical Trials
EXHIBIT C               Budget for PROGENICS Clinical Trials
EXHIBIT D               Adverse Event Reporting Form
EXHIBIT E               Sloan-Kettering Sublicense Agreement
EXHIBIT F               The Regents Sublicense Agreement
EXHIBIT G               Aquila Sublicense Agreement


                                      (iv)
<PAGE>

                 JOINT DEVELOPMENT AND MASTER LICENSE AGREEMENT

      THIS JOINT DEVELOPMENT AND MASTER LICENSE AGREEMENT (this "Agreement")
is dated as of April 15, 1997 between Progenics Pharmaceuticals, Inc., a
Delaware corporation, having offices at 777 Old Saw Mill River Road, Tarrytown,
New York 10591 ("PROGENICS"), and Bristol-Myers Squibb Company, a Delaware
corporation, having offices at P.O. Box 4000, Route 206 and Province Line Road,
Princeton, New Jersey 08543-4000, for and on behalf of itself and its Affiliates
("BMS").

                             PRELIMINARY STATEMENTS

      A. PROGENICS has acquired a license to certain patents and technology
relating to the treatment of human cancers using vaccines pursuant to a license
agreement dated November 17, 1994 (the "Sloan-Kettering License Agreement")
between PROGENICS and Sloan-Kettering Institute for Cancer Research, a
not-for-profit membership corporation of the State of New York
("Sloan-Kettering").

      B. PROGENICS has also entered into a license agreement dated June 25, 1996
("The Regents License Agreement") with The Regents of The University of
California, a California corporation ("The Regents") pursuant to which PROGENICS
acquired a license to certain patent rights relating to such vaccines.

      C. In addition, PROGENICS has entered into a license and supply agreement
dated August 31, 1995 (the "Aquila License and Supply Agreement") with Aquila
Biopharmaceuticals, Inc. (formerly known as Cambridge Biotech Corporation)
("Aquila"), pursuant to which PROGENICS has acquired a license to certain Aquila
technology and patent rights needed to formulate certain of such vaccines, and
Aquila supplies to PROGENICS one of the ingredients in certain of the vaccines
being developed by PROGENICS.

      D. Research and development of certain of the technology licensed to
PROGENICS by Sloan-Kettering, The Regents and Aquila is being conducted on
behalf of PROGENICS by various cancer centers and cooperative cancer research
groups in the United States, Europe, Australia and New Zealand.

      E. The Parties desire to collaborate with respect to the development,
commercialization and marketing of the Licensed Products upon the terms and
conditions set forth in this Agreement and in the agreements contemplated
hereby. In connection therewith, BMS desires to obtain, and PROGENICS desires to
grant to BMS, a license to certain technical information of PROGENICS and
sublicenses for certain of the Sloan-Kettering technology, The Regents
technology and the Aquila technology pursuant to sublicense agreements as
contemplated by this Agreement.


                                       -1-
<PAGE>

      F. It is anticipated that BMS and Aquila will enter into a supply
agreement, pursuant to which it is contemplated that Aquila will provide BMS
with one of the ingredients in certain of the vaccines being developed by BMS
and PROGENICS under this Agreement, on terms and conditions substantially the
same as those between PROGENICS and Aquila pursuant to the Aquila License and
Supply Agreement.

      NOW, THEREFORE, in consideration of the mutual covenants and agreements of
the Parties contained in this Agreement, the Parties agree as follows:

1. DEFINITIONS.

      As used in this Agreement, the following terms will have those meanings
set forth in this Section 1 unless the context dictates otherwise.

      1.1 "Adjuvant" shall have the meaning ascribed to such term in the Aquila
Sublicense Agreement.

      1.2 "Affiliate", with respect to any Party, shall mean any Person which,
directly or indirectly, controls, is controlled by, or is under common control
with, such Party. For these purposes, "control" shall refer to: (i) the
possession, directly or indirectly, of the power to direct the management or
policies of a Person or to veto any material decision relating to the management
or policies of a Person, in each case, whether through the ownership of equity
participation, voting securities or beneficial interests, by contract, by
agreement, or otherwise.

      1.3 "Aquila Field of Use" shall have the meaning ascribed to such term in
the Aquila Sublicense Agreement.

      1.4 "Aquila Knowhow" shall have the meaning ascribed to such term in the
Aquila Sublicense Agreement.

      1.5 "Aquila Licensed Patent Rights" shall have the meaning ascribed to
such term in the Aquila Sublicense Agreement.

      1.6 "Aquila Licensed Product" shall have the meaning ascribed to such term
in the Aquila Sublicense Agreement.

      1.7 "Aquila Sublicense Agreement" shall have the meaning set forth in
Section 5.4.

      1.8 "BCG" shall mean bacille de Calmette et Guerin, a nonspecific immune
stimulant (cow tuberculosis) vaccine.

      1.9 "BMS Clinical Trials" shall have the meaning set forth in Section
4.5(c).


                                      -2-
<PAGE>

      1.10 "Clinical Trial Agreements" shall have the meaning set forth in
Section 4.1.

      1.11 "Compound" shall mean any of BCG, GM2, GD2, KLH and QS-21.

      1.12 "Confidential Information" shall mean the collection of technical
information included in the Licensed Technical Information or technical
information of BMS, all information required to be kept confidential by
PROGENICS pursuant to the terms of the Sloan-Kettering License Agreement, The
Regents License Agreement or the Aquila License and Supply Agreement, and
confidential non-public information concerning BMS's or PROGENICS's business
plans, strategy and the like. All information which shall be disclosed in
confidence by the disclosing party to the receiving party, and which affords a
competitive advantage to the disclosing party or its Affiliates, shall be
presumed to be Confidential Information, even though limited portions of such
technical information may be in the public domain. In addition, the material
financial terms of this Agreement shall be considered Confidential Information
of both Parties.

            The following information shall be excluded from the definition of
Confidential Information: (a) information which the receiving party demonstrates
was in the receiving party's possession in written or other tangible form prior
to any disclosure; (b) information which the receiving party demonstrates was
received from a third party without restriction and not in violation of any duty
of nondisclosure on the part of such third party; (c) information which is
independently discovered or invented by personnel of a party who do not have
direct or indirect access to the information provided to that party by the other
party; or (d) from the time it becomes so known, any information which the
receiving party demonstrates was generally known to the trade. Information shall
not be considered to be generally known to the trade if, in order to acquire
such information from publicly available sources, the receiving party used the
disclosing party's Confidential Information to guide it in reviewing such
sources in order to select therefrom a series of relatively unconnected
information which may be fit together to match the Confidential Information
first learned from the disclosing party.

      1.13 "Derivative" shall mean a chemical substance derived from another
substance either directly or by modification or partial substitution.

      1.14 "Effective Date" shall mean the date first above written as the date
of this Agreement.

      1.15 "FDA" shall mean the United States Food and Drug Administration, or
the successor thereto.


                                       -3-
<PAGE>

      1.16 "First Commercial Sale" shall mean, in each country of the Territory,
the date that Licensed Product(s) are first sold, marketed or publicly made
available for sale. Licensed Products distributed or used for clinical trials or
experimental purposes only shall not be considered sold, marketed or made
publicly available and shall not establish the First Commercial Sale.

      1.17 "GD2" shall mean [XXX].

      1.18 "Generic Product" shall mean, on a country-by-country basis, a
Licensed Product: (i) the manufacture, use or sale of which is not covered by a
Valid Claim in such country, and (ii) that is also marketed by an unlicensed
Third Party or Parties in such country, which Third Party or Parties have, in
the aggregate, at least [XXX] in such country, as measured by IMS.

      1.19 "GM2" shall mean [XXX].

      1.20 "GMK Development Completion" shall have the meaning set forth in
Section 4.5(f).

      1.21 "GMK Vaccine" shall mean that certain Licensed Product composed of
GM2 conjugated to KLH and combined with QS-21.

      1.22 "Joint Steering Committee" shall have the meaning set forth in
Section 3.1.

      1.23 "KLH" shall mean keyhole limpet hemocyanin.

      1.24 "Licensed Patents" shall mean all S-K Licensed Patents, Regents'
Patent Rights and Aquila Licensed Patent Rights. All Licensed Patents existing
on the Effective Date are set forth on Exhibit A attached.

      1.25 "Licensed Products" shall mean any product for the treatment or
prevention of neoplastic human disease or the treatment or prevention of human
cancer which contains as an active ingredient: (i) GM2, (ii) GD2, or (iii) any
combination of the foregoing, including, without limitation, S-K Products,
Regents' Products and Aquila Products.

      1.26 "Licensed Technical Information" shall mean all S-K Technical
Information, all Aquila Knowhow and all PROGENICS Technical Information.

      1.27 "MGV Development Completion" shall have the meaning set forth in
Section 4.5(g).


                                       -4-
<PAGE>

      1.28 "MGV Vaccine" shall mean that certain Licensed Product composed of
GM2 conjugated to KLH and combined with GD2 conjugated to KLH and further
combined with QS-21.

      1.29 "Net Sales" shall mean the gross amount invoiced by BMS [XXX]. Such 
amounts shall be determined from the books and records of BMS, its Affiliates or
Sub-sublicensees, maintained in accordance with the accounting principles used
by such entity, consistently applied.

      1.30 "Party" shall mean PROGENICS or BMS and, when used in the plural,
shall mean PROGENICS and BMS.

      1.31 "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, or any organization which can exercise independent legal standing.

      1.32 "PROGENICS Clinical Trials" shall have the meaning set forth in
Section 4.1.

      1.33 "PROGENICS License" shall have the meaning set forth in Section 5.1.

      1.34 "PROGENICS Technical Information" shall mean unpublished research and
development information, unpatented inventions, formulae, processes, know-how,
trade secrets, and technical data which PROGENICS owns or has acquired a license
to or to which PROGENICS has the right to grant licenses or sublicenses (other
than the S-K Technical Information or the Aquila Knowhow), as of the Effective
Date or at any time during the term of this Agreement, which relate to the
Compounds and/or the Licensed Products or which are needed to produce or gain
government approvals to market Licensed Products.

      1.35 "QS-21" shall mean [XXX].


                                       -5-
<PAGE>

      1.36 "Regents' Field" shall have the meaning ascribed to such term in The
Regents Sublicense Agreement.

      1.37 "Regents' Method" shall have the meaning ascribed to such term in The
Regents Sublicense Agreement.

      1.38 "Regents' Patent Rights" shall have the meaning ascribed to such term
in The Regents Sublicense Agreement.

      1.39 "Regents' Products" shall have the meaning ascribed to such term in
The Regents Sublicense Agreement.

      1.40 "S-K Field" shall have the meaning ascribed to such term in the
Sloan-Kettering Sublicense Agreement.

      1.41 "S-K Licensed Patents" shall have the meaning ascribed to such term
in the Sloan-Kettering Sublicense Agreement.

      1.42 "S-K Products" shall have the meaning ascribed to such term in the
Sloan-Kettering Sublicense Agreement.

      1.43 "S-K Technical Information" shall have the meaning ascribed to such
term in the Sloan-Kettering Sublicense Agreement.

      1.44 "Sloan-Kettering Sublicense Agreement" shall have the meaning set
forth in Section 5.2.

      1.45 "Sub-sublicensee" shall mean any non-Affiliate Third Party who is
granted sublicense rights by BMS pursuant to this Agreement, the Sloan-Kettering
Sublicense Agreement, The Regents Sublicense Agreement or the Aquila Sublicense
Agreement.

      1.46 "Territory" shall mean the entire world.

      1.47 "The Regents Sublicense Agreement" shall have the meaning set forth
in Section 5.3.

      1.48 "Third Party" shall mean any Person who or which is neither a Party
nor an Affiliate of a Party.

      1.49 "Valid Claim" shall mean a claim of any Licensed Patent which has not
been held invalid or unenforceable by final decision of a court or other
governmental agency of competent jurisdiction, unappealed or unappeased within
the time allowed for appeal, and which is not admitted to be invalid or
unenforceable through reissue, disclaimer or otherwise.

2.    REPRESENTATIONS AND WARRANTIES.

      2.1 Representations and Warranties of Both Parties. Each Party represents
and warrants to the other Party that: (i) it is free to enter into this
Agreement; (ii) in so doing, it will not violate any other agreement to which it
is a party; (iii) it has


                                       -6-
<PAGE>

taken all corporate action necessary to authorize the execution and delivery of
this Agreement and the performance of its obligations under this Agreement; and
(iv) no person or entity has or will have, as a result of the transactions
contemplated by this Agreement, any right, interest or valid claim against or
upon such Party for any commission, fee or other compensation as a finder or 
broker because of any act or omission by such Party or any of its agents.

      2.2 Representations and Warranties of PROGENICS. PROGENICS hereby
represents and warrants to BMS that:

            (a) Each of the Sloan-Kettering License Agreement, The Regents
License Agreement, the Aquila License and Supply Agreement and the Clinical
Trial Agreements which have been executed as of the Effective Date are in full
force and effect; PROGENICS has complied with all provisions of all said
agreements; there does not exist any event of default with respect to PROGENICS
under any said agreement which, after notice or lapse of time or both, would
constitute an event of default with respect to PROGENICS under said agreement;
and PROGENICS has no knowledge of any breach or anticipated breach by any other
party to any said agreement;

            (b) PROGENICS has all consents necessary to grant the rights and
licenses granted to BMS under this Agreement;

            (c) PROGENICS has: (1) exclusive rights to all of the S-K Licensed
Patents in the S-K Field; (2) exclusive rights to all of the Regents' Patent
Rights in the Regents' Field; and (3) co-exclusive rights to all of the Aquila
Licensed Patent Rights in the Aquila Field of Use; and has the exclusive right
(except with respect to the Aquila Licensed Patent Rights, for which it has the
co-exclusive right) to grant sublicenses to each of the foregoing;

            (d) To the best of PROGENICS's knowledge, PROGENICS has: (1)
exclusive rights to all of the PROGENICS Technical Information; (2) exclusive
rights to all of the S-K Technical Information in the S-K Field; and (3)
co-exclusive rights to all of the Aquila Knowhow in the Aquila Field of Use, and
has the exclusive right (except with respect to the Aquila Knowhow, for which it
has the co-exclusive right) to grant sublicenses to each of the foregoing;

            (e) To the best of PROGENICS's knowledge, all of the Licensed
Patents in existence on the Effective Date are in full force and effect and have
been maintained to date;

            (f) PROGENICS is not aware of any asserted or unasserted claim or
demand which it believes can be enforced against such Licensed Patents;

            (g) To the best of PROGENICS's knowledge, after due investigation,
the Licensed Patents and the Licensed Technical Information constitute all of
the proprietary rights necessary for


                                       -7-
<PAGE>

the formulation of that certain GMK Vaccine and that certain MGV Vaccine, each
as currently under development, in finished form, and the distribution and sale
of that certain GMK Vaccine and that certain MGV Vaccine, each as currently
under development, by BMS in accordance with the terms of this Agreement, and
such formulation, distribution and sale do not infringe upon or conflict with
any patent or other proprietary rights of any Third Party; and

            (h) PROGENICS has not entered into any agreement with any Third
Party which is in conflict with the rights granted to BMS pursuant to this
Agreement.

3.    JOINT STEERING COMMITTEE.

      3.1 Creation. PROGENICS and BMS shall establish a joint steering committee
(the "Joint Steering Committee"), which shall consist of an equal number of
representatives appointed by each of the Parties. Within 30 days after the
execution of this Agreement by both Parties, PROGENICS and BMS shall determine
the number of representatives to be appointed initially to the Joint Steering
Committee, and each shall appoint its representatives to serve on the Committee.
Each Party may designate appropriate personnel who shall assist the
representatives of the Party. Each Party shall be free to change its
representatives, on notice to the other Party. The Joint Steering Committee
shall meet at such times and in such places as agreed upon from time to time by
the Parties. The Joint Steering Committee will be chaired by one representative,
who shall be appointed by BMS from time to time. The Joint Steering Committee
shall exist until the expiration or termination of this Agreement.

      3.2 Purpose. The Joint Steering Committee shall have the following
responsibilities: (i) to select Licensed Products for development pursuant to
this Agreement, provided that the Parties agree that the GMK Vaccine and the MGV
Vaccine shall be chosen for such development; (ii) to plan, supervise and
coordinate the development of Licensed Products; (iii) to review overall
strategic development plans and budgets, clinical study protocols, clinical
study write-ups, NDA submissions, and the like; (iv) to review all studies
relating to the Licensed Products and any other studies proposed to be performed
by either Party in connection with the registration process for the Licensed
Products; (v) to make changes to development strategies, as deemed necessary or
desirable; (vi) to provide a mechanism for the exchange of information with
regard to Licensed Technical Information and the Licensed Products; (vii) to
resolve disputes between the Parties with respect to the foregoing; and (viii)
to have such other responsibilities assigned to the Joint Steering Committee
pursuant to this Agreement or as may be mutually agreed upon by the Parties from
time to time.

      3.3 Meetings. The Joint Steering Committee will meet at least once each
calendar quarter during the term of this Agreement, or less frequently as the
Parties may mutually agree is appropriate


                                       -8-
<PAGE>

from time to time, at such dates and times as agreed to by the Parties. Meetings
in person shall alternate between the offices of the Parties or such other place
as may be mutually agreed upon. The Joint Steering Committee may also convene or
be polled or consulted from time to time by means of telecommunications or
correspondence. All decisions made or actions taken by the Joint Steering
Committee will be made unanimously by its members with the PROGENICS members
cumulatively having one vote and the BMS members cumulatively having one vote.
The Secretary of the Joint Steering Committee will prepare written minutes of
each meeting and a written record of all decisions, whether made at a formal
meeting or not. A quorum for a meeting shall require at least one PROGENICS
member and at least one BMS member.

      3.4 Deadlock. If there are issues on which the Joint Steering Committee
cannot reach agreement because of a deadlock (as hereinafter defined), such
matters shall be referred for further review and resolution to [XXX]. For the 
purpose of this Section 3.4, "deadlock" will mean (i) with respect to any matter
considered and voted upon by the Joint Steering Committee, that one Party votes
in favor of such matter and the other Party does not vote in favor of such
matter, or (ii) a quorum cannot be established for the Joint Steering Committee
to vote on a matter.

4.    PRODUCT DEVELOPMENT.

      4.1 Current Research Collaborations. The Parties acknowledge that
PROGENICS has entered into, or has commenced negotiations for, contracts
(collectively, the "Clinical Trial Agreements") with the following cancer
research organizations for the conduct of the following clinical trials
(collectively, the "PROGENICS Clinical Trials"):

            (a) [XXX];

            (b) [XXX]


                                       -9-
<PAGE>

[XXX];

            (c) [XXX];

            (d) [XXX];

            (e) [XXX];

            (f) [XXX];

            (g) [XXX];

            (h) [XXX]; and

            (i) [XXX].

            A description of each of the PROGENICS Clinical Trials currently
being conducted, or scheduled to commence pursuant to any of the Clinical Trial
Agreements, is set forth in Exhibit B.

      4.2 Continued Development of Licensed Products by PROGENICS. During the
term of this Agreement, PROGENICS shall continue the development of the GMK
Vaccine and the MGV Vaccine pursuant to the Clinical Trial Agreements, under the
auspices of,


                                      -10-
<PAGE>

and subject to review and approval by, the Joint Steering Committee; provided
that BMS shall pay PROGENICS for all reasonable costs paid or incurred by
PROGENICS with respect to the performance of the PROGENICS Clinical Trials by
the respective cancer research organizations. In the event that any of the
PROGENICS Clinical Trials are terminated prior to completion for any reason,
PROGENICS shall use all reasonable efforts to promptly close-out such PROGENICS
Clinical Trial in a cost-efficient manner. BMS shall pay PROGENICS for any
non-cancelable third party costs and any internal costs paid or incurred by
PROGENICS with respect to such close-out for a period of six months after
termination of such PROGENICS Clinical Trial.

            (a) Attached to this Agreement as Exhibit C is a budget (the
"Budget") that details [XXX]. The Budget is not intended to provide a maximum
amount of funding to be provided by BMS to PROGENICS pursuant to this Section
4.2. However, the Budget is intended to set forth all of the tasks currently
contemplated as necessary to complete the PROGENICS Clinical Trials, [XXX].

            (b) BMS shall make payments to PROGENICS based on the amount
included in the Budget for each calendar quarter. Such amount shall be paid in
quarterly installments in advance on the first day of January, April, July and
October of each year, with adjustments made from time to time as required, but
in any event at the end of each calendar year, based on the statements submitted
by PROGENICS to BMS pursuant to Section 4.2(c). However, the first payment shall
be made in the amount of [XXX] on the Effective Date of this Agreement (in lieu 
of any payment on April 1, 1997).

            (c) Within 30 days following the end of each calendar quarter,
PROGENICS shall submit a statement to BMS showing [XXX].

            (d) BMS shall have the right, at reasonable times and upon
reasonable notice, to examine those records as may be necessary to determine the
correctness of any statement submitted


                                      -11-
<PAGE>

by PROGENICS pursuant to Section 4.2(c). Results of any such examination shall
be made available to both Parties.

      4.3 Conduct of Development by PROGENICS. During the conduct of the
PROGENICS Clinical Trials, PROGENICS shall:

            (a) Use all reasonable efforts and proceed diligently to cause the
PROGENICS Clinical Trials to be conducted pursuant to the time schedule
anticipated in the respective Clinical Trial Agreements;

            (b) Cause the PROGENICS Clinical Trials to be conducted in good
scientific manner, and in compliance in all material respects with all
requirements of applicable laws, rules and regulations, and all other
requirements of any applicable good laboratory practices to attempt to achieve
its objectives efficiently and expeditiously;

            (c) Provide written progress reports to the Joint Steering Committee
within 30 days after the end of every second calendar quarter (ending for each
particular PROGENICS Clinical Trial upon completion of such PROGENICS Clinical
Trial), indicating efforts and progress toward achieving research tasks and
development milestones described in the respective Clinical Trial Agreements;
and

            (d) Allow representatives of BMS, upon reasonable notice and during
normal business hours, to consult informally, during visits to PROGENICS and by
telephone, with personnel involved in the PROGENICS Clinical Trials.

      4.4 Delivery of Data: Transfer of IND.

            (a) During the term of this Agreement, promptly upon the completion
of each of the PROGENICS Clinical Trials, PROGENICS shall deliver to BMS copies
of all reports, data, results and other information relating to the GMK Vaccine
and/or the MGV Vaccine from such PROGENICS Clinical Trial, including, without
limitation, all reports, data, results and other information received under any
of the Clinical Trial Agreements.

            (b) Upon completion of all of the PROGENICS Clinical Trials relating
to the GMK Vaccine pursuant to all of the Clinical Trial Agreements, or such
earlier time as the Parties may agree, PROGENICS shall promptly transfer to BMS
the IND relating to the GMK Vaccine.

            (c) Upon completion of all of the PROGENICS Clinical Trials relating
to the MGV Vaccine pursuant to all of the Clinical Trial Agreements, or such
earlier time as the Parties may agree, PROGENICS shall promptly transfer to BMS
the IND relating to the MGV Vaccine.


                                      -12-
<PAGE>

            (d) At the request of BMS at any time after the Effective Date,
PROGENICS shall promptly provide to BMS a copy of the IND relating to the GMK
Vaccine and/or the MGV Vaccine.

      4.5 Development by BMS.

            (a) Except for the PROGENICS Clinical Trials to be conducted
pursuant to any of the Clinical Trial Agreements with respect to the GMK Vaccine
and the MGV Vaccine, as of the Effective Date, BMS shall be obligated to conduct
all development and regulatory activity with respect to Licensed Products,
including the payment of all costs and expenses associated therewith except as
otherwise provided in this Agreement, necessary to obtain approvals throughout
the Territory. Such development and regulatory activities shall include,
without limitation, those set forth in Section 5 of the Sloan-Kettering
Sublicense Agreement, Section 5 of The Regents Sublicense Agreement and Section
5 of the Aquila Sublicense Agreement.

            (b) BMS shall provide to the Joint Steering Committee a development
plan, as amended from time to time by BMS (each, a "Development Plan"),
outlining BMS's development objectives for Licensed Products during the
forthcoming period. A new Development Plan shall be submitted to the Joint
Steering Committee in writing at least three months prior to the end of the
period covered by the Development Plan in effect at the time of such submission.
Development Plans shall be submitted, as provided herein, until the later of:
(i) the First Commercial Sale of a Licensed Product has occurred in any country
in the Territory; or (ii) a Licensed Product has been approved for marketing by
the FDA.

            (c) BMS shall be responsible for the preparation of all further
protocols and the conduct of all further studies proposed to be conducted or
required to be conducted by any regulatory authority in any country in the
Territory in connection with the registration process for each Licensed Product
in accordance with the Development Plan in effect at such time for such Licensed
Product (all of the foregoing studies, collectively, the "BMS Clinical Trials"),
including, without limitation, payment for all costs and expenses associated
with all of the foregoing.

            (d) BMS shall use all commercially reasonable efforts necessary or
desirable to register each Licensed Product in all countries in the Territory,
in the name of BMS (or its designated Affiliate or Sub-sublicensee), as soon as
practicable; provided, however, that BMS shall not be obligated under this
Section 4.5(d) or Sections 4.5(c) or 4.5(e) with respect to any country in the
Territory where BMS does not have all legal rights deemed reasonably necessary
by BMS for BMS to sell and market Licensed Products in such country. BMS shall
be responsible for all costs associated with the regulatory filing and approval
processes for the Licensed Products in all countries in the Territory. PROGENICS
shall provide all technical data and support necessary for BMS to make such
regulatory filings. BMS shall keep PROGENICS informed as


                                      -13-
<PAGE>

to the status of such efforts from time to time. During such process, the
Parties shall cooperate in the preparation and filing of all documents necessary
therefor and all regulatory interactions and compliance with regulatory
authorities in the Territory.

            (e) BMS shall use all commercially reasonable efforts necessary or
desirable to market and sell each Licensed Product in each country in the
Territory as soon as practicable following receipt of all governmental approvals
in such country necessary therefor.

            (f) Consistent with BMS's development obligations with respect to
the GMK Vaccine as provided in Section 4.5(a), except as provided in Section
10.3(a), BMS shall be obligated to develop the GMK Vaccine pursuant to this
Agreement [XXX].

            (g) Consistent with BMS's development obligations with respect to
the MGV Vaccine as provided in Section 4.5(a), except as provided in Section
10.3(d), BMS shall be obligated to develop the MGV Vaccine pursuant to this
Agreement [XXX].

      4.6 BMS Diligence Milestones.

            (a) BMS, its Affiliates or its Sub-sublicensees shall achieve the
following objectives in accordance with the following schedule:

                  (i)   [XXX].

                  (ii)  [XXX].

            (b) Failure to achieve these objectives shall result in PROGENICS
having the option to terminate the PROGENICS License granted under this
Agreement, subject to BMS's right to achieve the missed objective within 60 days
of receipt of written notice of termination from PROGENICS. PROGENICS shall not
unreasonably withhold its consent to any revision in the preceding schedule
requested in writing by BMS and supported by evidence of technical difficulties
or delays in the clinical studies or regulatory process that could not have been
reasonably avoided. Notwithstanding the foregoing, PROGENICS shall not have the
right


                                      -14-
<PAGE>

to terminate the PROGENICS License for the failure of BMS to meet a goal if such
failure is a result of (i) causes beyond BMS's direct control; (ii) PROGENICS's
failure to meet its obligations hereunder; (iii) infringement of Third Party
patents; or (iv) actions or inactions of a federal or state agency whose
approval is required for commercial sales.

            (c) The Parties further acknowledge and agree that the milestones
contained in this Section 4.6 were established on the assumption that the
milestones would apply to development of the GMK Vaccine. In the event that
development of the GMK Vaccine is terminated due to safety or efficacy reasons,
the parties agree that the milestones set forth in this Section 4.6 shall not
apply and the Parties will negotiate in good faith to establish new milestones.

            (d) PROGENICS agrees that, in the event that Sloan-Kettering agrees
to change the schedule for achievement of any comparable milestone contained in
the Sloan-Kettering License Agreement, or otherwise waives compliance with such
milestone, the comparable milestone in this Section 4.6 shall automatically be
changed or waived by PROGENICS in like manner.

      4.7 Conduct of BMS Clinical Trials. During the conduct of the BMS Clinical
Trials, BMS shall:

            (a) Use all reasonable efforts and proceed diligently to conduct the
development of Licensed Products as set forth in the applicable Development
Plan(s) and as required by Sections 4.5 and 4.6;

            (b) Conduct the development of the Licensed Products in good
scientific manner, and in compliance in all material respects with all
requirements of applicable laws, rules and regulations, and all other
requirements of any applicable good laboratory practices to attempt to achieve
its objectives efficiently and expeditiously;

            (c) Provide written progress reports to the Joint Steering Committee
within 30 days after the end of every second calendar quarter (ending for each
particular Licensed Product with the First Commercial Sale of that particular
Licensed Product), indicating efforts and progress toward achieving research
tasks and development milestones described in the Development Plan; and

            (d) Allow representatives of PROGENICS, upon reasonable notice and
during normal business hours, to visit the facilities where any aspect of the
BMS Clinical Trials are being conducted, and consult informally, during such
visits and by telephone, with personnel performing work on the BMS Clinical
Trials.


                                      -15-
<PAGE>

      4.8 Records.

            (a) Each Party shall maintain records, in sufficient detail and in
good scientific manner, which shall be complete and accurate and shall fully and
properly reflect all work done and results achieved in the performance of the
PROGENICS Clinical Trials and the BMS Clinical Trials, respectively (including
all data in the form required under all applicable laws and regulations).

            (b) Each Party shall have the right, during normal business hours
and upon reasonable notice, to inspect and copy all such records of the other
Party to the extent reasonably required for the performance of its obligations
under this Agreement. Each Party shall maintain such records and information
contained therein in confidence in accordance with Section 9 and shall not use
such records or information except to the extent otherwise permitted by this
Agreement.

      4.9 Pricing Matters. Notwithstanding anything in this Agreement to the
contrary, BMS may elect not to pursue a product registration for a Licensed
Product or market a Licensed Product in any country in the European Union
because the government-approved reimbursement price or government fixed price in
such country is substantially lower than the price BMS is selling or proposes to
sell such Licensed Product for in other countries in the Territory. In such
event, BMS shall notify PROGENICS of such and PROGENICS shall not have the right
and option to terminate this Agreement as to such country pursuant to Section
10.2; provided that BMS shall use its best efforts to obtain a satisfactory
government-approved reimbursement price or government fixed price in such
country.

      4.10 Adverse Reaction Reporting.

            (a) Each Party shall record, investigate, summarize and review all
adverse drug experiences associated with the Compounds and the Licensed
Products. In order that each Party may be fully informed of the adverse drug
experiences known to the other Party associated therewith, each Party shall
report:

                  (1)   In the case of PROGENICS, to:

                        Progenics Pharmaceuticals, Inc.
                        777 Old Saw Mill River Road
                        Tarrytown, NY 10591
                        Attention: Dr. Paul Maddon
                        Facsimile No.: (914) 789-2817
                        Telephone No.: (914) 789-2800


                                      -16-
<PAGE>

                  (2)   In the case of BMS, to:

                        Bristol-Myers Squibb Company
                        P.O. Box 4000
                        Route 206 & Province Line Road
                        Princeton, New Jersey 08543-4000
                        Attention: Trevor Woodward, M.D.
                        Vice President, Worldwide Safety and Surveillance
                        Facsimile No.: (609) 252-3804
                        Telephone No.: (609) 252-3737

all "adverse events" involving the Compounds and/or the Licensed Products ("AE
Reports"). "Serious" adverse events shall be reported to the other Party within
three (3) working days of a Party's becoming aware of such an event (a
"reporting party") and shall either be reported by facsimile or telephone. The
reporting party shall report all other adverse events on a monthly basis. In
addition, the reporting party shall report all known instances of use of a
Licensed Product during pregnancy. Attached as Exhibit D is a sample of an
adverse event reporting form which may be used by the reporting party as a basis
for such reports. The form indicates the information sought with each report. In
any event, each Party shall promptly notify the other of any complaint received
by such Party in sufficient detail and in sufficient time to allow the
responsible party to comply with any and all regulatory requirements imposed
upon it in any country in their respective territories. Each Party shall also
advise the other of any regulatory developments (e.g., proposed recalls,
labeling and other registrational dossier changes, etc.) affecting the Compounds
or the Licensed Products in any country.

            (b) An "adverse event" is any negative symptom experienced at the
time of or after the taking of the drug, whether or not considered drug related,
including any side effects, injury, toxicity or sensitivity reaction, or
significant failure of expected pharmacological action. Also included are
instances of symptomatic overdose, abuse or withdrawal reactions.

            (c) A "serious" adverse event is one that is life-threatening; that
is, an adverse event that puts the patient at risk of dying, requires
hospitalization, prolongs existing hospitalization or results in permanent
disability, birth defect, cancer or death.

5.    GRANT OF RIGHTS.

      5.1 Grant of License Under this Agreement. PROGENICS hereby grants to BMS
an exclusive (even as to PROGENICS) right and license to use the PROGENICS
Technical Information to make, have made, use, sell, have sold and develop
Licensed Products throughout the Territory, pursuant to the terms and conditions
set forth in this Agreement, in connection with BMS's performance of its


                                      -17-
<PAGE>

obligations and exercise of its rights under this Agreement, the Sloan-Kettering
Sublicense Agreement, The Regents Sublicense Agreement and the Aquila Sublicense
Agreement (the "PROGENICS License").

      5.2 Grant of Sublicense Under Sloan-Kettering License Agreement. PROGENICS
grants BMS an exclusive (even as to PROGENICS) sublicense, under the
Sloan-Kettering License Agreement, to use the S-K Licensed Patents and the S-K
Technical Information to make, have made, use, sell, have sold and develop S-K
Products in the S-K Field throughout the Territory, pursuant to the terms and
conditions set forth in the Sublicense Agreement by and between BMS and
PROGENICS, dated as of the date hereof (the "Sloan-Kettering Sublicense
Agreement"), a copy of which is attached as Exhibit E.

      5.3 Grant of Sublicense Under The Regents License Agreement. PROGENICS
grants BMS an exclusive (even as to PROGENICS) sublicense, under The Regents
License Agreement, to use the Regents' Patent Rights in jurisdictions where the
Regents' Patent Rights exist, to make, have made, use, sell, have sold and offer
to sell Regents' Products and to practice the Regents' Method in the Regents'
Field, pursuant to the terms and conditions set forth in the Sublicense
Agreement by and between BMS and PROGENICS, dated as of the date hereof ("The
Regents Sublicense Agreement"), a copy of which is attached as Exhibit F.

      5.4 Grant of Sublicense Under Aquila License and Supply Agreement.
PROGENICS grants BMS a non-exclusive, worldwide sublicense under the Aquila
License and Supply Agreement to use the Aquila Knowhow and practice the Aquila
Licensed Patent Rights to develop, manufacture, have manufactured, use, sell,
and have sold Aquila Licensed Products, pursuant to the terms and conditions set
forth in the Sublicense Agreement by and between BMS and PROGENICS, dated as of
the date hereof (the "Aquila Sublicense Agreement"), a copy of which is attached
as Exhibit G.

      5.5 Sublicense Rights.

            (a) BMS shall have the right to grant sublicenses to its Affiliates
of the PROGENICS License granted to BMS herein, provided that: (i) BMS shall
guarantee and be responsible for the making of all payments due, and the making
of reports under this Agreement, by reason of sales of any Licensed Products by
its Affiliates and their compliance with all applicable terms of this Agreement;
and (ii) each Affiliate agrees in writing to keep books and records and permit
PROGENICS to review such books and records pursuant to the relevant provisions
and to observe all other applicable terms of this Agreement. No consent or
approval of PROGENICS shall be required in connection with the granting of such
sublicenses.

            (b) BMS shall have the right to grant sublicenses to
Sub-sublicensees of the PROGENICS License granted to BMS herein,


                                      -18-
<PAGE>

except that BMS does not have the right to grant such sublicenses with respect
to the United States, provided that: (i) PROGENICS shall have consented to such
sublicense, which consent shall not be unreasonably withheld (it will be
reasonable for PROGENICS to withhold consent if PROGENICS determines that the
capabilities of the proposed Sub-sublicensee are not comparable to BMS's
capabilities in the country or countries to be sublicensed); (ii) BMS shall
guarantee and be responsible for the making of all payments due, and the making
of reports under this Agreement, by reason of sales of any Licensed Products by
its Sub-sublicensees and their compliance with all applicable terms of this
Agreement; and (iii) each Sub-sublicensee agrees in writing to keep books and
records and permit PROGENICS to review such books and records pursuant to the
relevant provisions and to observe all other applicable terms of this Agreement.

            (c) BMS hereby unconditionally guarantees the performance of any of
its Affiliates and Sub-sublicensees hereunder. In the event of a breach by an
Affiliate or Sub-sublicensee in the observance of applicable terms of this
Agreement, PROGENICS shall be entitled to proceed against either such Affiliate
or Sub-sublicensee or directly against BMS, as PROGENICS may determine in its
sole discretion, to enforce this Agreement.

      5.6 Reservation of Rights by PROGENICS. The PROGENICS License granted
under this Agreement and the sublicenses granted under each of the
Sloan-Kettering Sublicense Agreement, The Regents Sublicense Agreement and the
Aquila Sublicense Agreement are exclusive to BMS, except that PROGENICS reserves
the right to use the Licensed Patents and the Licensed Technical Information,
without cost, and subject to the confidentiality provisions of this Agreement,
for non-commercial internal research and development purposes.

6.    UP-FRONT, MILESTONE AND ROYALTY PAYMENTS.

      6.1 Reimbursement of Expenses. As reimbursement to PROGENICS for expenses
incurred by PROGENICS in the development of the GMK Vaccine and the MGV Vaccine
conducted by PROGENICS prior to the Effective Date, BMS shall pay to PROGENICS
the sum of: [XXX] upon the execution of this Agreement by both Parties. Such sum
shall be non-refundable.

      6.2 Up-front Fee. As consideration to PROGENICS for the grant of the
sublicenses to BMS pursuant to the Sloan-Kettering Sublicense Agreement, The
Regents Sublicense Agreement and the Aquila Sublicense Agreement, BMS shall pay
to PROGENICS the sum of: [XXX] reduced by the sum of the up-front fees being 
made by BMS to PROGENICS pursuant to Section 4.1 of the Sloan-Kettering


                                      -19-
<PAGE>

Sublicense Agreement, Section 4.1 of The Regents Sublicense Agreement and
Section 4.1 of the Aquila Sublicense Agreement. Such up-front fee shall be paid
upon the execution of this Agreement by both Parties. Such sum shall be
non-refundable.

      6.3 Milestone Payments Regarding GMK Vaccine. As consideration to
PROGENICS for the development of the GMK Vaccine conducted by PROGENICS prior to
the Effective Date, the PROGENICS License granted to BMS by PROGENICS under this
Agreement and the sublicense granted to BMS by PROGENICS pursuant to The Regents
Sublicense Agreement, and subject to prior termination of this Agreement in
whole or in all countries in the Territory with respect the Licensed Product to
which any milestone payment relates, BMS shall pay to PROGENICS the following
milestone payments upon the occurrence of each event set forth below:

            (a) [XXX];

            (b) [XXX];

            (c) [XXX];

            (d) [XXX];

            (e) [XXX];

            (f) [XXX];


                                      -20-
<PAGE>

            (g) [XXX];

            (h) [XXX];

            (i) [XXX]; and

            (j) [XXX].

            Each of the foregoing milestone payments shall be reduced by the
amount of the milestone payment made by BMS to PROGENICS for the comparable
milestone pursuant to Section 4.2 of The Regents Sublicense Agreement.

            Each of the payments required pursuant to this Section 6.3 shall be
paid within 30 days after such milestone has been achieved, and shall be
non-refundable.

      6.4 Milestone Payments Regarding MGV Vaccine. As consideration to
PROGENICS for the development of the MGV Vaccine conducted by PROGENICS prior to
the Effective Date, the PROGENICS License granted to BMS by PROGENICS under this
Agreement and the sublicense granted to BMS by PROGENICS pursuant to The Regents
Sublicense Agreement, and subject to prior termination of this Agreement in
whole or in all countries in the Territory with respect the Licensed Product to
which any milestone payment relates, BMS shall pay to PROGENICS the following
milestone payments upon the occurrence of each event set forth below:

            (a) [XXX];

            (b) [XXX];


                                      -21-
<PAGE>

            (c) [XXX];

            (d) [XXX];

            (e) [XXX];

            (f) [XXX]; and

            (g) [XXX].

            With respect to the milestones set forth in Sections 6.4(b) through
(g) above, the Parties may mutually agree to cause any of such milestones to
apply to another cancer type with comparable projected market potential as the
cancer type set forth in such milestone.

            Each of the foregoing milestone payments shall be reduced by the
amount of the milestone payment made by BMS to PROGENICS for the comparable
milestone pursuant to Section 4.3 of The Regents Sublicense Agreement.

            Each of the payments required pursuant to this Section 6.4 shall be
paid within 30 days after such milestone has been achieved and shall be
non-refundable.

      6.5 Royalty Payments. As consideration to PROGENICS for the development of
the GMK Vaccine and the MGV Vaccine conducted by PROGENICS prior to the
Effective Date and for the PROGENICS License and other rights (excluding the
sublicenses) granted to BMS by PROGENICS under this Agreement, during the term
of this Agreement, BMS shall pay to PROGENICS a royalty on Net Sales of any
Licensed Product commencing on the First Commercial Sale of such Licensed
Product by BMS, its Affiliates or its Sub-sublicensees as follows:

            (a) With respect to the GMK Vaccine:

                  (i) With respect to those countries in the Territory where 
such Licensed Product is not a Generic Product:


                                      -22-
<PAGE>

                        (A) [XXX] of the Net Sales of such Licensed Product in
                  such countries for any calendar year until Net Sales of such
                  Licensed Product throughout the Territory in such calendar
                  year equal [XXX]; and

                        (B) After Net Sales of such Licensed Product throughout
                  the Territory in such calendar year exceed [XXX], [XXX] of any
                  further Net Sales of such Licensed Product in such countries 
                  until the end of such calendar year;

                  reduced by:

                        (C) The sum of the royalty payments due by BMS to
                  PROGENICS during the comparable period with respect to such
                  Licensed Product pursuant to Sections 4.2(a)(i) and (ii) of
                  the Sloan-Kettering Sublicense Agreement, Section 4.4(a) of
                  The Regents Sublicense Agreement and Sections 4.2(a)(i) and
                  (ii) of the Aquila Sublicense Agreement.

                        (ii) With respect to those countries in the Territory
where such Licensed Product is a Generic Product:

                        (A) [XXX] of the Net Sales of such Licensed Product in
                  such countries for any calendar year until Net Sales of such
                  Licensed Product throughout the Territory in such calendar
                  year equal [XXX]; and

                        (B) After Net Sales of such Licensed Product throughout
                  the Territory in such calendar year exceed [XXX], [XXX] of any
                  further Net Sales of such Licensed Product in such countries 
                  until the end of such calendar year;

                  reduced by:

                        (C) The sum of the royalty payments due by BMS to
                  PROGENICS during the comparable period with respect to such
                  Licensed Product pursuant to Section 4.2(a)(iii) of the
                  Sloan-Kettering Sublicense Agreement and Section 4.2(a)(iii)
                  of the Aquila Sublicense Agreement.

                        (iii) Royalties shall be paid at the royalty rates set
forth in Sections 6.5(a)(i)(A) and 6.5(a)(ii)(A) (reduced by the amounts set
forth in Sections 6.5(a)(i)(C) and 6.5(a)(ii)(C), respectively) through the
end of the calendar quarter preceding the calendar quarter in which annual Net
Sales in all countries throughout the Territory first exceed [XXX] in any year. 
Royalties shall be paid at the royalty rates set forth in Sections


                                      -23-
<PAGE>

6.5(a)(i)(B) and 6.5(a)(ii)(B) (reduced by the amounts set forth in Sections
6.5(a)(i)(C) and 6.5(a)(ii)(C), respectively) for the calendar quarter in which
annual Net Sales in all countries throughout the Territory first exceed [XXX] in
any year, and for each calendar quarter in such year thereafter other than the
last calendar quarter of such year. Following the end of the last calendar
quarter of each year, the total amount of royalties actually due for such year
shall be calculated as provided in Section 6.5(a)(iv) (as such amount has been
reduced by the amounts set forth in Sections 6.5(a)(i)(C) and 6.5(a)(ii)(C)),
and such amount of royalties shall be paid, reduced by (A) the total amount of
royalties paid with respect to such Licensed Product throughout the Territory
for the first three calendar quarters of such year (as such amount has been
reduced by the amounts set forth in Sections 6.5(a)(i)(C) and 6.5(a)(ii)(C),
respectively), and further reduced by (B) the total amount of royalties paid or
due with respect to such Licensed Product throughout the Territory for such year
pursuant to Section 4.2(a)(iv) of the Sloan-Kettering Sublicense Agreement,
Section 4.4(a) of The Regents Sublicense Agreement and Section 4.2(a)(iv) of the
Aquila Sublicense Agreement (after giving effect, for purposes of this
calculation, to any credit due to BMS pursuant to any of the foregoing sections
of any of the sublicense agreements, which credit shall be extinguished to the
extent given effect therefor). The calculation of the amount to be paid with
respect to the fourth calendar quarter of each year shall be included on the
royalty report for such calendar quarter. In the event that BMS has paid more
royalties during the first three calendar quarters of any year than BMS owes for
the entire year, BMS shall be entitled to a credit, equal to the amount of such
excess royalties paid, to be applied against [XXX] of accrued royalties until
the entire credit has been used.

                        (iv) The total amount of royalties actually due for
each year under this Section 6.5(a) (before such amount has been reduced by the
amounts set forth in Sections 6.5(a)(i)(C) and 6.5(a)(ii)(C)) shall be
calculated as follows:

                        (A) The royalty rate set forth in Section 6.5(a)(i)(A)
                  shall be applied to that amount of Net Sales of such Licensed
                  Product determined under the formula X(1) x Y(1)/Z;

                        (B) The royalty rate set forth in Section 6.5(a)(i)(B)
                  shall be applied to that amount of Net Sales of such Licensed
                  Product determined under the formula X(2) x Y(1)/Z;

                        (C) The royalty rate set forth in Section 6.5(a)(ii)(A) 
                  shall be applied to that amount of Net Sales of such Licensed 
                  Product determined under the formula X(1) x Y(2)/Z; and

                        (D) The royalty rate set forth in Section 6.5(a)(ii)(B) 
                  shall be applied to that amount of


                                      -24-
<PAGE>

                  Net Sales of such Licensed Product determined under the
                  formula X(2) x Y(2)/Z;

            Where:

            X(1)     =    the smaller of: (i) the actual annual Net Sales of
                          such Licensed Product throughout the Territory for
                          such year, or (ii) [XXX]

            X(2)     =    the actual annual Net Sales of such Licensed Product
                          throughout the Territory for such year in excess of
                          [XXX]

            Y(1)     =    the annual Net Sales of such Licensed Product for such
                          year in all countries when Section 6.5(a)(i) applies

            Y(2)     =    the annual Net Sales of such Licensed Product for such
                          year in all countries when Section 6.5(a)(ii) applies

            Z        =    the annual Net Sales of such Licensed Product for such
                          year in all countries in the Territory

            (b) With respect to the MGV Vaccine and any other Licensed Products:

                  (i) With respect to those countries in the Territory where 
such Licensed Product is not a Generic Product:

                        (A) [XXX] of the Net Sales of such Licensed Product in
                  such countries for any calendar year;

                  reduced by:

                        (B) the sum of the royalty payments due by BMS to
                  PROGENICS during the comparable period with respect to such
                  Licensed Product pursuant to Sections 4.2(b)(i), (ii) and (iv)
                  of the Sloan-Kettering Sublicense Agreement, Section 4.4(b)
                  of The Regents Sublicense Agreement and Sections 4.2(b)(i) and
                  (ii) of the Aquila Sublicense Agreement.

                        (ii) With respect to those countries in the Territory
where such Licensed Product is a Generic Product:

                        (A) [XXX] of the Net Sales of such Licensed Product in 
                  such countries for any calendar year;

                  reduced by:


                                      -25-
<PAGE>

                        (B) the sum of the royalty payments due by BMS to
                  PROGENICS during the comparable period with respect to such
                  Licensed Product pursuant to Section 4.2(b)(iii) of the
                  Sloan-Kettering Sublicense Agreement and Section 4.2(b)(iii)
                  of the Aquila Sublicense Agreement.

            (c) The royalty rates applicable to Generic Products pursuant to
Sections 6.5(a)(ii) and 6.5(b)(ii), respectively, shall apply to Net Sales in
any country commencing with the calendar quarter during which such Licensed
Product first becomes a Generic Product in such country.

      6.6 Reductions to Royalties. BMS shall be entitled to deduct from the
royalties payable pursuant to Section 6.5:

            (a) All costs and expenses incurred by BMS in connection with the
exercise of its rights under: (i) Section 3 of that certain side letter
agreement proposed to be entered into among Sloan-Kettering, PROGENICS and BMS;
(ii) Section 3 of that certain side letter agreement proposed to be entered into
among The Regents, PROGENICS and BMS; and (iii) Section 3 of that certain side
letter agreement proposed to be entered into among Aquila, PROGENICS and BMS;
and

            (b) The amount of any credit to which BMS is entitled pursuant to
Section 8.3(c).

      6.7 Obligation to Pay Royalties. The obligation to pay royalties to
PROGENICS under this Section 6 is imposed only once with respect to the same
unit of Licensed Product regardless of the number of Licensed Patents pertaining
thereto. BMS shall only be entitled to a credit against royalties or a reduction
of the royalty rate once with respect to any Licensed Product in any country
pursuant to any provision in this Agreement. There shall be no obligation to pay
royalties to PROGENICS under this Section 6 on sales of Licensed Products among
BMS, its Affiliates and Sub-sublicensees, but in such instances the obligation
to pay royalties shall arise upon the sale by BMS, its Affiliates or
Sub-sublicensees to Third Parties. Payments due under this Section 6 shall be
deemed to accrue when Licensed Products are shipped or billed, whichever event
shall first occur. In the instance where BMS, its Affiliates or Sub-sublicensees
use the Licensed Product or provide it as part of some other service or product,
a royalty shall be due to PROGENICS at the time such Licensed Product is used or
provided based on a Net Sales amount equal to the price at which BMS or its
Affiliate or Sub-sublicensee sells such Licensed Product to Third Parties in the
country in which the Licensed Product was used or provided.


                                      -26-
<PAGE>

7.    PAYMENTS AND REPORTS.

      7.1 Reports; Payments. Except as otherwise specifically provided in this
Agreement, all payments due under this Agreement shall be paid quarterly within
50 days after the end of each calendar quarter. Each such payment for running
royalties shall be accompanied by a statement, Licensed Product-by-Licensed
Product and country-by-country, of the amount of Net Sales during such quarter
and the amount of royalties due on such Net Sales and, with respect to the last
calendar quarter of each year, such report shall include the calculation of the
adjustment referred to in Section 6.5(a)(iii).

      7.2 Mode of Payment; Taxes. All payments due under this Agreement shall be
paid by wire transfer of funds to an account at PROGENICS's designated bank in
New York, New York, and shall be paid in U.S. Dollars, calculated at BMS's
customary internal corporate monthly exchange rates for the last month of the
calendar quarter for which remittance is made for royalties. Such payments shall
be free of any taxes, charges, or remittance fees, except for income tax levied
upon or required to be withheld and paid by BMS, its Affiliates or its
Sub-sublicensees for the account of PROGENICS. BMS shall provide PROGENICS
appropriate receipts of payment of such withholding taxes or other proof
thereof. For each month and each currency, BMS's customary internal corporate
monthly exchange rate shall equal the arithmetic average of the daily exchange
rates (obtained as described below) during the period from (i) the 20th day of
the preceding month (or, if such 20th day is not a business day, the immediately
preceding business day) through (ii) the 19th day of the current month (or, if
such 19th day is not a business day, the immediately preceding business day);
each daily exchange rate shall be obtained from the Reuters Daily Rate Report or
The Wall Street Journal, Eastern U.S. Edition, or, if not so available, as
furnished by BMS's local Affiliates.

      7.3 Records Retention. BMS and its Affiliates and Sub-sublicensees shall
keep accurate records of all operations affecting payments hereunder, and shall
permit PROGENICS or its duly authorized agent to inspect all such records and to
make copies of or extracts from such records during regular business hours
throughout the term of this Agreement and for a reasonable period of not less
than 3 years thereafter.

      7.4 Audit Request. At the request and expense of PROGENICS, BMS and its
Affiliates and Sub-sublicensees shall permit PROGENICS or an independent,
certified public accountant appointed by PROGENICS and reasonably acceptable to
BMS, at reasonable times and upon reasonable notice, to examine those records as
may be necessary to: (i) determine the correctness of any report or payment made
under this Agreement; or (ii) obtain all information as to Net Sales and the
royalties payable for any calendar quarter. If an accountant is used, said
accountant shall not disclose to PROGENICS any information other than
information relating to said


                                      -27-
<PAGE>

reports, royalties, and payments. Results of any such examination shall be made
available to both Parties.

      7.5 Cost of Audit. PROGENICS shall bear the full cost of the performance
of any such audit except as hereinafter set forth. If, as a result of any
inspection of the books and records of BMS, its Affiliates or its
Sub-sublicensees, it is shown that BMS's payments under this Agreement were less
than the amount which should have been paid, then BMS shall make all payments
required to be made to eliminate any discrepancy revealed by said inspection
within 30 days after PROGENICS's demand therefor, plus interest at the prime
rate from the date payment should have been made. Furthermore, if the payments
were less than the amount which should have been paid by an amount in excess of
five percent of the payments actually made during the period in question, BMS
shall also reimburse PROGENICS for the costs of such audit in addition to the
payment required to be made to eliminate any discrepancy.

      7.6 No Non-Monetary Consideration for Sales. Without the prior written
consent of PROGENICS, BMS and its Affiliates and Sub-sublicensees shall not
accept or solicit any non-monetary consideration in the sale of Licensed
Products other than as would be reflected in Net Sales. The use by BMS and its
Affiliates and Sub-sublicensees of commercially reasonable amounts of Licensed
Products for clinical trials and promotional sampling shall not violate this
provision.

8.    INDEMNIFICATION; INFRINGEMENT.

      8.1 Indemnification.

            (a) PROGENICS shall defend, indemnify and hold BMS and its
Affiliates and Sub-sublicensees, and each of their respective directors,
officers and employees, harmless from and against any and all claims, suits or
demands for liability, damages, losses, costs and expenses (including the costs
and expenses of attorneys and other professionals) arising out of Third Party
claims or suits resulting from a breach of PROGENICS's representations and
warranties set forth in Section 2, or from the performance of the PROGENICS
Clinical Trials.

            (b) If required by Section 10.4(g), PROGENICS shall defend,
indemnify and hold BMS and its Affiliates and Sub-sublicensees, and each of
their respective directors, officers and employees, harmless from and against
any and all claims, suits or demands for liability, damages, losses, costs and
expenses (including the cost and expenses of attorneys and other professionals)
arising out of PROGENICS' use of any data, information or government
registrations returned or provided to PROGENICS pursuant to Section 10.4(g),
including any use by any subsequent sublicensee of PROGENICS, or the
development, manufacture, marketing, use and/or sale of products or services
from any of the foregoing.


                                      -28-
<PAGE>

            (c) BMS shall defend, indemnify and hold PROGENICS, its Affiliates,
and their respective directors, officers and employees, harmless from and
against any and all claims, suits or demands for liability, damages, losses,
costs and expenses (including the costs and expenses of attorneys and other
professionals) arising out of: (i) Third Party claims or suits resulting from
(1) a breach of BMS's representations and warranties set forth in Section 2, (2)
the performance of the BMS Clinical Trials, (3) the manufacture, packaging, use,
sale, rental or lease of Licensed Products, even if altered or used for a
purpose not intended, or (4) the use of Licensed Patents or Licensed Technical
Information by BMS, its Affiliates or its Sub-sublicensees or its (or their)
customers and any representation made or warranty given by BMS, its Affiliates
or its Sub-sublicensees with respect to Licensed Products, Licensed Patents or
Licensed Technical Information, or (ii) claims or suits by Sloan-Kettering, The
Regents and/or Aquila against PROGENICS as a result of BMS's actions under this
Agreement.

            (d) As the Parties intend complete indemnification, all costs and
expenses of enforcing this Section 8.1 shall also be reimbursed by the
indemnifying Party.

      8.2 Conditions to Indemnification. A person or entity that intends to
claim indemnification under Section 8.1 (the "Indemnitee") shall promptly notify
the other Party (the "Indemnitor") of any loss, claim, damage, liability or
action in respect of which the Indemnitee intends to claim such indemnification,
and the Indemnitor shall assume the defense thereof with counsel mutually
satisfactory to the Indemnitee whether or not such claim is rightfully brought;
provided, however, that an Indemnitee shall have the right to retain its own
counsel, with the fees and expenses to be paid by the Indemnitor if Indemnitor
does not assume the defense, or if representation of such Indemnitee by the
counsel retained by the Indemnitor would be inappropriate due to actual or
potential differing interests between such Indemnitee and any other person
represented by such counsel in such proceedings. The indemnity agreement in
Section 8.1 shall not apply to amounts paid in settlement of any loss, claim,
damage, liability or action if such settlement is effected without the consent
of the Indemnitor, which consent shall not be withheld or delayed unreasonably.
The failure to deliver notice to the Indemnitor within a reasonable time after
the commencement of any such action, only if prejudicial to its ability to
defend such action, shall relieve such Indemnitor of any liability to the
Indemnitee under Section 8.1, but the omission so to deliver notice to the
Indemnitor will not relieve it of any liability that it may have to any
Indemnitee otherwise than under Section 8.1. The Indemnitee under Section 8.1,
its officers, directors, employees and agents, shall cooperate fully with the
Indemnitor and its legal representatives in the investigations of any action,
claim or liability covered by this indemnification.


                                      -29-
<PAGE>

      8.3 Infringement Action by Third Parties.

            (a) In the event of the institution of any suit by a Third Party
against BMS for patent infringement involving the manufacture, sale,
distribution or marketing of any Licensed Products in the Territory and such
infringement claim is a result of the use of the PROGENICS Technical
Information, BMS shall promptly notify PROGENICS in writing of such suit.
PROGENICS may defend such action at PROGENICS's sole expense on behalf of BMS
with attorneys of its own selection, and BMS hereby agrees to assist and
cooperate with PROGENICS, at its own expense, to the extent necessary in the
defense of such suit. In such event (i.e., where PROGENICS has elected to defend
in accordance with the preceding sentence), PROGENICS shall bear the full costs
and expenses of such defense (including fees of attorneys and other
professionals) and, in any event, whether or not PROGENICS has elected to defend
such action, PROGENICS shall assume full responsibility for the payment of any
award for damages, or any amount due pursuant to any settlement entered into by
PROGENICS with such Third Party, which PROGENICS shall have the right to do in
its sole discretion. In addition, BMS shall be entitled to retain its own
counsel in such proceedings, at BMS's sole expense. During the pendency of such
action, BMS shall continue to make all payments due under this Agreement.

            (b) If PROGENICS does not commence a defense of such action with 90
days after receiving notice thereof, BMS shall have the right to defend such
suit at its own expense, and PROGENICS hereby agrees to assist and cooperate
with BMS, at its own expense, to the extent necessary in the defense of such
suit. In such event, BMS shall not enter into any settlement arrangement or
other amicable arrangement without the prior written consent of PROGENICS.
During the pendency of such action, BMS shall continue to make all payments due
under this Agreement.

            (c) If as a result of any judgment, award, decree or settlement
resulting from an action instituted by a Third Party, BMS is required to pay a
royalty to such Third Party, BMS shall continue to pay the royalties for such
Licensed Product in the country which is the subject of such action, [XXX].

9.    CONFIDENTIALITY AND NON-USE.

      9.1 Notification. Both Parties recognize that each may wish to publish the
results of their work relating to the Compounds and the Licensed Products.
However, both Parties also recognize the importance of acquiring patent
protection. Consequently,


                                      -30-
<PAGE>

subject to any applicable laws or regulations obligating either Party to do
otherwise (including any laws or regulations applicable to any of the
cooperative research groups conducting any of the PROGENICS Clinical Trials, to
the extent applicable to the Parties), any proposed publication by either Party
shall comply with this Section 9. At least 60 days before a manuscript is to be
submitted to a publisher, the publishing Party will provide the other Party with
a copy of the manuscript. If the publishing Party wishes to make an oral
presentation, it will provide the other Party with a copy of the abstract (if
one is submitted) at least 40 days before it is to be submitted. The publishing
Party will also provide to the other Party a copy of the text of the
presentation, including all slides, posters, and any other visual aids, at least
40 days before the presentation is made.

      9.2 Review of Proposed Publications. The receiving Party will review the
manuscript, abstract, text or any other material provided under Section 9.1 to
determine if patentable subject matter is disclosed. The reviewing Party will
notify the publishing Party within 30 days of receipt of the proposed
publication if the reviewing Party, in good faith, determines that patentable
subject matter is or may be disclosed, or if the reviewing Party, in good faith,
believes Confidential Information or proprietary information is or may be
disclosed. If it is determined by the reviewing Party that patent applications
should be filed, the publishing Party shall delay its publication or
presentation for a period not to exceed 90 days from the reviewing Party's
receipt of the proposed publication to allow time for the filing of patent
applications covering patentable subject matter. In the event that the delay
needed to complete the filing of any necessary patent application will exceed
the 90 day period, the Parties will discuss the need for obtaining an extension
of the publication delay beyond the 90 day period. If it is determined in good
faith by the reviewing Party that Confidential Information or proprietary
information is being disclosed, the Parties will consult in good faith to arrive
at an agreement on mutually acceptable modifications to the proposed publication
to avoid such disclosure.

      9.3 Confidentiality and Non-use; Exceptions. Except to the extent
expressly authorized by this Agreement or otherwise agreed in writing, the
Parties agree that, for the term of this Agreement and for five (5) years
thereafter the receiving Party and its Affiliates and Sub-sublicensees shall
keep, and shall ensure that its officers, directors, employees and agents keep,
completely confidential and shall not publish or otherwise disclose and shall
not use for any purpose any Confidential Information furnished to it by the
other Party or its Affiliates or Sub-sublicensees or developed under the
PROGENICS Clinical Trials, the BMS Clinical Trials or otherwise pursuant to this
Agreement.

      9.4 Authorized Disclosure. Each Party may disclose the other's data and
information, including Confidential Information, to its Affiliates, licensors
and Sub-sublicensees, and its and


                                      -31-
<PAGE>

their officers, directors, employees and outside consultants, as reasonably
necessary, and to others to the extent such disclosure is reasonably necessary
in filing or prosecuting patent applications, prosecuting or defending
litigation, complying with applicable governmental laws and regulations,
undertaking basic research with outside collaborators, or conducting preclinical
or clinical trials, provided that if a Party is required to make any such
disclosure of the other Party's Confidential Information it will, except where
impracticable for necessary disclosures, for example to physicians conducting
studies or to health authorities, give reasonable advance notice to the other
Party of such disclosure requirement and, except to the extent inappropriate in
the case of patent applications, will use its best efforts to secure
confidential treatment of such information required to be disclosed.

10.   TERMINATION.

      10.1 Term. This Agreement shall commence as of the Effective Date of this
Agreement and, unless sooner terminated as provided hereunder, shall terminate
as follows:

            (a) As to each Licensed Product in each country in the Territory,
upon the later of: (i) 15 years from the First Commercial Sale of such Licensed
Product in such country, or (ii) the expiration of the last Valid Claim to
expire that covers the manufacture, use or sale of such Licensed Product in such
country.

            (b) This Agreement shall terminate in its entirety upon its
expiration with respect to all Licensed Products in all countries in the
Territory pursuant to Section 10.1(a).

      10.2 Breach.

            (a) Failure by either Party to comply with any of the material
obligations of such Party contained in this Agreement shall entitle the other
Party to give notice to the defaulting Party specifying the nature of the
default and requiring it to cure such default. If such default is not cured
within 60 days after the receipt of such notice (or, if such default cannot be
cured within such 60 day period, if the defaulting Party does not commence and
diligently continue actions to cure such default), the other Party shall be
entitled, without prejudice to any of its other rights conferred on it by this
Agreement, in addition to any other remedies available to it by law or in
equity, to terminate this Agreement by giving written notice to take effect
immediately. The right to terminate this Agreement, as hereinabove provided,
shall not be affected in any way by the other Party's waiver or failure to take
action with respect to any previous default.

            (b) Notwithstanding Section 10.2(a), in the event that BMS fails
materially to satisfy its development and/or marketing obligations with respect
to any Licensed Product in any country in


                                      -32-
<PAGE>

the Territory under this Agreement, the Sloan-Kettering Sublicense Agreement,
The Regents Sublicense Agreement or the Aquila Sublicense Agreement, such
failure shall not be deemed a breach of a material obligation of BMS pursuant to
Section 10.2(a) if such failure is by reason of force majeure as provided in
Section 11.2 or as provided in Section 4.9.

      10.3 Termination by BMS.

            (a) [XXX] Such termination shall be effective immediately upon 
receipt by PROGENICS of BMS's notice thereof, and BMS shall have no further
obligations to PROGENICS pursuant to this Agreement with respect to the GMK 
Vaccine other than to pay the close-out costs associated therewith pursuant to
Section 4.2 and to pay other amounts previously accrued under this Agreement.

            (b) Following [XXX], BMS shall have the right to terminate this
Agreement with respect to the GMK Vaccine throughout the Territory at any time
upon 60 days' prior written notice to PROGENICS.

            (c) Following regulatory approval of the GMK Vaccine in any country
in the Territory, BMS shall have the right to terminate this Agreement with
respect to the GMK Vaccine in such country at any time upon 60 days' prior
written notice to PROGENICS. In addition, following [XXX], BMS shall have the
right to terminate this Agreement with respect to the GMK Vaccine [XXX] during
such time upon 60 days' prior written notice to PROGENICS.

            (d) Upon [XXX], BMS shall have the right, at its sole discretion, to
terminate this Agreement, but only with respect to the MGV Vaccine, upon written
notice to PROGENICS, sent not later than 90 days after [XXX]. In such event,
from and after the date of such notice, BMS shall have no further obligations to
PROGENICS pursuant to this Agreement with respect to the MGV Vaccine, including,
without limitation, any obligation to make the milestone payments set forth in
Section 6.4 or to continue to fund any clinical trials or ongoing development
thereof, other than to pay the close-out costs associated therewith pursuant to
Section 4.2. Such termination shall be without prejudice to the rights of BMS to
develop the GMK Vaccine or any other Licensed Product pursuant to


                                      -33-
<PAGE>

this Agreement. If within such 90-day period BMS does not make such termination,
it shall be required to make the milestone payment required under Section
6.4(a).

            (e) Following [XXX], BMS shall have the right to terminate this
Agreement with respect to the MGV Vaccine throughout the Territory at any time
upon 60 days' prior written notice to PROGENICS.

            (f) Following regulatory approval of the MGV Vaccine in any country
in the Territory, BMS shall have the right to terminate this Agreement with
respect to the MGV Vaccine in such country at any time upon 60 days' prior
written notice to PROGENICS. In addition, following [XXX], BMS shall have the
right to terminate this Agreement with respect to the MGV Vaccine [XXX] during
such time upon 60 days' prior written notice to PROGENICS.

            (g) With respect to all other Licensed Products, BMS shall have the
right to terminate this Agreement with respect to any Licensed Product
throughout the Territory at any time upon 60 days' prior written notice to
PROGENICS.

            (h) Following regulatory approval of any other Licensed Product in
any country in the Territory, BMS shall have the right to terminate this
Agreement with respect to such Licensed Product in such country at any time upon
60 days' prior written notice to PROGENICS. In addition, at any time prior to
regulatory approval of any other Licensed Product [XXX], BMS shall have the
right to terminate this Agreement with respect to such other Licensed Product
[XXX] during such time upon 60 days' prior written notice to PROGENICS.

      10.4 Effect of Termination.

            (a) Upon termination of this Agreement with respect to the GMK
Vaccine throughout the Territory pursuant to Section 10.3(a) or 10.3(b), [XXX],
then BMS shall promptly: (1) provide to PROGENICS, at BMS's expense, all data
and information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to the GMK Vaccine throughout the Territory; (2) transfer, at
BMS's expense, to PROGENICS or such other Person as PROGENICS shall designate,
any and all rights that it may have


                                      -34-
<PAGE>

under any government registrations or authorizations in every country in the
Territory with respect to the GMK Vaccine; (3) cancel, at BMS's expense, any
government registrations or authorizations with respect to the GMK Vaccine as
may not be transferable; (4) provide to PROGENICS, at BMS's expense, all data
and information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to any such governmental registrations or authorizations in
every country in the Territory with respect to the GMK Vaccine; and (5)
discontinue all use, sale and distribution of the GMK Vaccine throughout the
Territory and the use of the Licensed Patents and Licensed Technical Information
in connection therewith. In such event, the PROGENICS License and the
sublicenses with respect to the GMK Vaccine granted to BMS pursuant to this
Agreement, the Sloan-Kettering License Agreement, The Regents Sublicense
Agreement and the Aquila Sublicense Agreement shall terminate with respect to
the GMK Vaccine throughout the Territory, subject to any rights BMS may have
hereunder and thereunder to continue to sell stock on hand pursuant to Section
10.5 of this Agreement, Section 8.5 of the Sloan-Kettering Sublicense Agreement,
Section 9.4 of The Regents Sublicense Agreement and Section 9.4 of the Aquila
Sublicense Agreement, respectively, but shall continue in effect for all other
Licensed Products in all countries throughout the Territory.

            (b) Upon termination of this Agreement with respect to the MGV
Vaccine throughout the Territory pursuant to Section 10.3(d) or 10.3(e), [XXX],
then BMS shall promptly: (1) provide to PROGENICS, at BMS's expense, all data
and information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to the MGV Vaccine throughout the Territory; (2) transfer, at
BMS's expense, to PROGENICS or such other Person as PROGENICS shall designate,
any and all rights that it may have under any government registrations or
authorizations in every country in the Territory with respect to the MGV
Vaccine; (3) cancel, at BMS's expense, any government registrations or
authorizations with respect to the MGV Vaccine as may not be transferable; (4)
provide to PROGENICS, at BMS's expense, all data and information in BMS's, or
its Affiliates' or Sub-sublicensees', possession or control relating to any such
governmental registrations or authorizations in every country in the Territory
with respect to the MGV Vaccine; and (5) discontinue all use, sale and
distribution of the MGV Vaccine throughout the Territory, and the use of the
Licensed Patents and Licensed Technical Information in connection therewith. In
such event, the PROGENICS License and


                                      -35-
<PAGE>

the sublicenses with respect to the MGV Vaccine granted to BMS pursuant to this
Agreement, the Sloan-Kettering License Agreement, The Regents Sublicense
Agreement and the Aquila Sublicense Agreement shall terminate with respect to
the MGV Vaccine throughout the Territory, subject to any rights BMS may have
hereunder and thereunder to continue to sell stock on hand pursuant to Section
10.5 of this Agreement, Section 8.5 of the Sloan-Kettering Sublicense Agreement,
Section 9.4 of The Regents Sublicense Agreement and Section 9.4 of the Aquila
Sublicense Agreement, respectively, but shall continue in effect for all other
Licensed Products in all countries throughout the Territory.

            (c) Upon termination of this Agreement with respect to any other
Licensed Product throughout the Territory pursuant to Section 10.3(g), then BMS
shall promptly: (1) provide to PROGENICS, at BMS's expense, all data and
information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to such Licensed Product throughout the Territory; (2)
transfer, at BMS's expense, to PROGENICS or such other Person as PROGENICS shall
designate, any and all rights that it may have under any government
registrations or authorizations in every country in the Territory with respect
to such Licensed Product; (3) cancel, at BMS's expense, any government
registrations or authorizations with respect to the GMK Vaccine as may not be
transferable; (4) provide to PROGENICS, at BMS's expense, all data and
information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to any such governmental registrations or authorizations in
every country in the Territory with respect to such Licensed Product; and (5)
discontinue all use, sale and distribution of such Licensed Product throughout
the Territory, and the use of the Licensed Patents and Licensed Technical
Information in connection therewith. In such event, the PROGENICS License and
the sublicenses with respect to such Licensed Product granted to BMS pursuant to
this Agreement, the Sloan-Kettering License Agreement, The Regents Sublicense
Agreement and the Aquila Sublicense Agreement shall terminate with respect to
such Licensed Product throughout the Territory, subject to any rights BMS may
have hereunder and thereunder to continue to sell stock on hand pursuant to
Section 10.5 of this Agreement, Section 8.5 of the Sloan-Kettering Sublicense
Agreement, Section 9.4 of The Regents Sublicense Agreement and Section 9.4 of
the Aquila Sublicense Agreement, respectively, but shall continue in effect for
all other Licensed Products in all countries throughout the Territory.

            (d) Upon termination of this Agreement in part with respect to any
country in the Territory and/or as to any Licensed Product pursuant to Section
10.3(c), 10.3(f) or 10.3(h), BMS shall promptly: (1) transfer, at BMS's expense,
to PROGENICS or such other Person as PROGENICS shall designate, any and all
rights that it may have under any government registrations or authorizations in
such country with respect to such Licensed Product; (2) cancel, at BMS's
expense, any government registrations or authorizations in such country with
respect to such Licensed Product as may not be transferable; (3) provide to
PROGENICS, at BMS's expense, all data


                                      -36-
<PAGE>

and information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to any such governmental registrations or authorizations in
such country with respect to such Licensed Product; (4) grant to PROGENICS, or
such other Person as PROGENICS shall designate, a royalty-free license to use
any trademark and/or trade name used by BMS in connection with such Licensed
Product in such country; and (5) discontinue all use, sale and distribution of
such Licensed Product in such country and the use of the Licensed Patents and
the Licensed Technical Information in connection therewith. In such event, the
PROGENICS License and the sublicenses with respect to such Licensed Product
granted to BMS pursuant to this Agreement, the Sloan-Kettering License
Agreement, The Regents Sublicense Agreement and the Aquila Sublicense Agreement
in such country shall terminate and revert to PROGENICS, subject to any rights
BMS may have hereunder and thereunder to continue to sell stock on hand pursuant
to Section 10.5 of this Agreement, Section 8.5 of the Sloan-Kettering Sublicense
Agreement, Section 9.4 of The Regents Sublicense Agreement and Section 9.4 of
the Aquila Sublicense Agreement, respectively, but shall continue in effect for
all other Licensed Products in all other countries throughout the Territory.

            (e) Upon termination of this Agreement in its entirety pursuant to
any provision in this Section 10 other than Section 10.1, BMS shall promptly:
(1) return to PROGENICS, at BMS's expense, all relevant data and other
information concerning the Licensed Patents and Licensed Technical Information
in the possession or control of BMS, its Affiliates and Sub-sublicensees; (2)
transfer, at BMS's expense, to PROGENICS or such other Person, as PROGENICS
shall designate, any and all rights that it may have under any government
registrations or authorizations in any country in the Territory with respect to
the Licensed Products; (3) cancel, at BMS's expense, any government
registrations or authorizations with respect to the Licensed Products as may not
be transferable; (4) provide to PROGENICS, at BMS's expense, all data and other
information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to such governmental registrations or authorities in any
country in the Territory with respect to all Licensed Products; and (5)
discontinue all use, sale and distribution of all Licensed Products throughout
the Territory, and the use of the Licensed Patents and Licensed Technical
Information in connection therewith. In such event, the PROGENICS License and
the sublicenses with respect to the Licensed Products granted to BMS pursuant to
this Agreement, the Sloan-Kettering License Agreement, The Regents Sublicense
Agreement and the Aquila Sublicense Agreement shall terminate and revert to
PROGENICS, subject to any rights BMS may have hereunder and thereunder to
continue to sell stock on hand pursuant to Section 10.5 of this Agreement,
Section 8.5 of the Sloan-Kettering Sublicense Agreement, Section 9.4 of The
Regents Sublicense Agreement and Section 9.4 of the Aquila Sublicense Agreement,
respectively.

            (f) Upon termination of this Agreement with respect to any Licensed
Product in any country in the Territory , or in its


                                      -37-
<PAGE>

entirety, pursuant to Section 10.1, BMS shall have the right to make, have made,
use, sell, have sold, and offer to sell such Licensed Product(s) in such country
or countries without further obligations to PROGENICS, and as provided in
Section 8.4(a) of the Sloan-Kettering Sublicense Agreement, Section 9.3(a) of
The Regents Sublicense Agreement and Section 9.1 of the Aquila Sublicense
Agreement, respectively.

            (g) In the event that BMS is required, pursuant to any provision of
this Section 10.4, to provide, return, transfer or otherwise convey any data,
information or government registrations or authorizations relating to any
Licensed Product in any country in the Territory, PROGENICS shall indemnify BMS
as provided in Section 8.1(b).

      10.5 Right to Sell Stock on Hand. If BMS is not in material breach of this
Agreement at the time of termination of this Agreement, then BMS shall have the
right for one year thereafter to dispose of all Licensed Products then in its
inventory, and shall pay royalties thereon, in accordance with the provisions of
this Agreement, as though this Agreement had not terminated.

      10.6 Termination of Sublicenses. Upon any termination of this Agreement,
all sublicenses granted by BMS under this Agreement shall terminate
simultaneously, subject, nevertheless, to Section 10.5.

      10.7 Accrued Rights, Surviving Obligations.

            (a) Termination, relinquishment or expiration of this Agreement for
any reason shall be without prejudice to any rights which shall have accrued to
the benefit of either Party prior to such termination, relinquishment or
expiration. Such termination, relinquishment or expiration shall not relieve
either Party from obligations which are expressly indicated to survive
termination or expiration of this Agreement.

            (b) All of the Parties' rights and obligations under Sections 4.8,
4.10, 7, 8, 9, 10.4, 10.5, 10.7, 11.14 and 11.15 shall survive termination.

11.   MISCELLANEOUS.

      11.1 Relationship of Parties. Nothing in this Agreement is intended or
shall be deemed to constitute a partnership, agency, employer-employee or joint
venture relationship between the Parties. No Party shall incur any debts or make
any commitments for the other, except to the extent, if at all, specifically
provided herein.

      11.2 Force Majeure. Neither Party shall be liable to the other for loss or
damages or shall have any right to terminate this Agreement for any default or
delay attributable to any act of God,


                                      -38-
<PAGE>

flood, fire, explosion, strike, lockout, labor dispute, shortage of raw
materials, casualty or accident, war, revolution, civil commotion, act of public
enemies, blockage or embargo, injunction, law, order, proclamation, regulation,
ordinance, demand or requirement of any government or subdivision, authority or
representative of any such government, or any other cause beyond the reasonable
control of such Party, if the Party affected shall give prompt notice of any
such cause to the other Party. The Party giving such notice shall thereupon be
excused from such of its obligations hereunder as it is thereby disabled from
performing for so long as it is so disabled and for 30 days thereafter.
Notwithstanding the foregoing, nothing in this Section 11.2 shall excuse or
suspend the obligation to make any payment due hereunder in the manner and at
the time provided.

      11.3 Assignment. Neither Party shall be entitled to assign its rights
hereunder, except that PROGENICS may otherwise assign its rights and transfer
its duties hereunder to any assignee of all or substantially all of its
business. No assignment and transfer shall be valid and effective unless and
until the assignee/transferee shall agree in writing to be bound by the
provisions of this Agreement.

      11.4 Further Actions. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all such other acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

      11.5 Notice. Any notice or request required or permitted to be given under
or in connection with this Agreement shall be deemed to have been sufficiently
given if in writing and personally delivered by messenger, facsimile
transmission (receipt verified), express courier service (signature required),
or telegram, prepaid, to the Party for which such notice is intended, at the
address set forth for such Party below:

            (a)   In the case of PROGENICS, to:

                  Progenics Pharmaceuticals, Inc.
                  777 Old Saw Mill River Road
                  Tarrytown, New York 10591
                  Attention: Dr. Paul Maddon
                  Facsimile No.: (914) 789-2817


                                      -39-
<PAGE>

            (b)   In the case of BMS, to:

                  Bristol-Myers Squibb Company
                  P.O. Box 4000
                  Route 206 & Province Line Road
                  Princeton, New Jersey 08543-4000
                  Attention:  Vice President and Senior Counsel,
                            Pharmaceutical Research Institute, and
                            Worldwide Franchise Management and
                            Strategic Business Development
                  Facsimile No.: (609) 252-4232

or to such other address for such Party as it shall have specified by like
notice to the other Party, provided that notices of a change of address shall be
effective only upon receipt thereof. If sent by messenger, facsimile
transmission, express courier service, or telegram, the date of mailing or
transmission shall be deemed to be the date on which such notice or request has
been given.

      11.6 Use of Name. Except as otherwise provided herein, neither Party shall
have any right, express or implied, to use in any manner the name or other
designation of the other Party or any other trade name or trademark of the other
Party for any purpose in connection with the performance of this Agreement.

      11.7 Public Announcements. Except as required by applicable law, neither
Party shall issue any press release or make any other public announcement
concerning this Agreement or the subject matter hereof without the prior written
consent of the other Party, which consent shall not be unreasonably withheld. In
the event of a required press release or other public announcement, the Party
making such announcement shall provide the other Party with a copy of the
proposed text prior to such announcement. The Parties agree that if either is
required to file this Agreement with any governmental agency, such Party will
redact the financial terms of this Agreement to the extent possible in order to
keep the financial terms of this Agreement confidential to the extent permitted
by law.

      11.8 Costs and Expenses. Except as otherwise expressly provided in this
Agreement, each Party shall bear all costs and expenses associated with the
performance of such Party's obligations under this Agreement.

      11.9 Waiver. A waiver by either Party of any of the terms and conditions
of this Agreement in any instance shall not be deemed or construed to be a
waiver of such term or condition for the future, or of any subsequent breach
hereof. All rights, remedies, undertakings, obligations and agreements contained
in this Agreement shall be cumulative and none of them shall be in limitation of
any other remedy, right, undertaking, obligation or agreement of either Party.


                                      -40-
<PAGE>

      11.10 Inconsistency. If there is any inconsistency between the provisions
of this Agreement and any purchase order or other document passing between the
Parties, the provisions of this Agreement shall control and be determinative.

      11.11 Compliance with Law. Nothing in this Agreement shall be deemed to
permit a Party to export, reexport or otherwise transfer any Licensed Product
sold under this Agreement without compliance with applicable laws.

      11.12 Severability. When possible, each provision of this Agreement will
be interpreted in such manner as to be effective and valid under applicable law,
but if any provision of this Agreement is held to be prohibited by or invalid
under applicable law, such provision will be ineffective only to the extent of
such prohibition or invalidity, without invalidating the remainder of this
Agreement.

      11.13 Amendment. No amendment, modification or supplement of any
provisions of this Agreement shall be valid or effective unless made in writing
and signed by a duly authorized officer of each Party.

      11.14 Governing Law. This Agreement shall be governed by and interpreted
in accordance with the laws of the State of New York without regard to its
choice of law principles.

      11.15 Arbitration. Any dispute arising out of or relating to any
provisions of this Agreement shall be finally settled by arbitration to be held
in New York, New York, under the auspices and then current commercial
arbitration rules of the American Arbitration Association. Such arbitration
shall be conducted by three (3) arbitrators appointed according to said rules.
Judgment upon any award rendered may be entered in any court having
jurisdiction, or application may be made to such court for a judicial acceptance
of the award and an order of enforcement, as the case may be.

      11.16 Entire Agreement. This Agreement, together with the Sloan-Kettering
Sublicense Agreement, The Regents Sublicense Agreement, the Aquila Sublicense
Agreement, the side letter agreements proposed to be entered into among BMS,
PROGENICS and each of Sloan-Kettering, The Regents and Aquila, and the Exhibits
attached hereto and thereto, sets forth the entire agreement and understanding
between the Parties as to the subject matter hereof and merges all prior
discussions and negotiations between them, and neither of the Parties shall be
bound by any conditions, definitions, warranties, understandings or
representations with respect to such subject matter other than as expressly
provided herein or as duly set forth on or subsequent to the date hereof in
writing and signed by a proper and duly authorized officer or representative of
the Party to be bound thereby.


                                      -41-
<PAGE>

      11.17 Counterparts. This Agreement may be executed simultaneously in any
number of counterparts, any one of which need not contain the signature of more
than one Party but all such counterparts taken together shall constitute one and
the same agreement.

      11.18 Descriptive Headings. The descriptive headings of this Agreement are
for convenience only, and shall be of no force or effect in construing or
interpreting any of the provisions of this Agreement.

      IN WITNESS WHEREOF, each of the Parties has caused this Agreement to be
executed and delivered by its duly authorized officer as of the day and year
first above written.

                                        PROGENICS PHARMACEUTICALS, INC.


                                        By: /s/ Paul J. Maddon
                                            -----------------------------
                                        Name:  Paul J. Maddon, M.D., Ph.D.
                                        Title: Chairman and Chief
                                                 Executive Officer

                                        BRISTOL-MYERS SQUIBB COMPANY


                                        By: /s/ Charles Linzner
                                            -----------------------------
                                        Name:  Charles Linzner
                                        Title: Vice President


                                      -42-
<PAGE>

                                   EXHIBIT A

                            LIST OF LICENSED PATENTS

A. S-K Licensed Patents

Application or Patent Number        Filing or Issue Date
- ----------------------------        --------------------

          [XXX]                            [XXX]


B. Aquila Licensed Patent Rights

Application or Patent Number        Filing or Issue Date
- ----------------------------        --------------------

U.S. Patent No. 5,057,540           October 15, 1991

          [XXX]                            [XXX]

Canadian Patent No. 1,331,443       August 16, 1994
European Patent No. 362,279         January 11, 1995
German Patent No. 3,852,761         February 23, 1995

C. Regents' Patent Rights

Application or Patent Number        Filing or Issue Date
- ----------------------------        --------------------

U.S. Patent No. 4,557,931           December 10, 1985
<PAGE>

                                    EXHIBIT B

                    DESCRIPTION OF PROGENICS CLINICAL TRIALS

1.    001 GMK Phase III Clinical Trial

      [XXX].

2.    002 GMK Phase III Clinical Trial

      [XXX].

3.    003 GMK Phase III Clinical Trial

      [XXX].

4.    004 MGV Phase I/II Clinical Trial

      [XXX].
<PAGE>

                                  EXHIBIT C

                     BUDGET FOR PROGENICS CLINICAL TRIALS


                                      [XXX]


Costs in subsequent years through completion are estimated to be equivalent.
<PAGE>

                                    EXHIBIT D

                          ADVERSE EVENT REPORTING FORM
<PAGE>

                      [LOGO] Bristol-Myers Squibb Company
                             Pharmaceutical Research Institute

                                                      Approved by FDA: 11/01/93 
                                                      ------------------------- 
                                                      Mfr report #              
                                                                                
                                                      ------------------------- 
                                                      UF/Dist report #          
                                                                                
                                                      ------------------------- 
MED WATCH
- ------------------------------------------                         FDA Use Only 
THE FDA MEDICAL PRODUCTS REPORTING PROGRAM            ------------------------- 
- ------------------------------------------

                                   Page    of

- --------------------------------------------------------------------------------
A. Patient information
- --------------------------------------------------------------------------------

1. Patient identifier   2. Age at time          3. Sex          4. Weight
                           of event:               [_] female   ________ lbs
                          or ________________                      or
                           Date                    [_] male     ________ kgs
   in confidence           of birth:

- --------------------------------------------------------------------------------
B. Adverse event or product problem
- --------------------------------------------------------------------------------

1. [_] Adverse event    and/or      [_] Product problem
- --------------------------------------------------------------------------------

2. Outcomes attributed to adverse event
   (check all that apply)                   [_] disability

   [_] death ______________________         [_] congenital anomaly

   [_] life-threatening                     [_] required intervention to prevent
                                                permanent impairment/damage
   [_] hospitalization-initial or prolonged
                                            [_] other

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

3. Date of                                   4. Date of
   event                                        this report

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

5. Describe event or problem




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

6. Relevant tests/laboratory data




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

7. Other relevant history, including preexisting medical conditions




- --------------------------------------------------------------------------------
C. Suspect medication(s)
- --------------------------------------------------------------------------------

1. Name
________________________________________________________________________________

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

2. Dose, frequency & route used           3. Therapy dates

___________________________________         ____________________________________

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

4. Diagnosis for use                      5. Event abated after use
                                             stopped or dose reduced
____________________________________        [_] yes  [_] no  [_] doesn't apply
                                            ___________________________________
- -----------------------------------------
                                            [_] yes  [_] no  [_] doesn't apply
6. Lot #                 7. Exp. date
                                           -------------------------------------
___________________        _______________ 
                                           8. Event reappeared after 
                                              reintroduction
- ------------------------------------------
9. NDC #                                    [_] yes  [_] no  [_] doesn't apply
                                            ____________________________________

                                            [_] yes  [_] no  [_] doesn't apply

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

10. Concomitant medical products



- --------------------------------------------------------------------------------
G. All manufacturers
- --------------------------------------------------------------------------------

1. Contact office - name/address                       2. Phone number

                                                       _________________________

                                                       3. Report source
                                                          (check all that apply)

                                                          [_] foreign

                                                          [_] study

                                                          [_] literature

                                                          [_] consumer
- ------------------------------------------------------
                                                          [_] health
4. Date received by manufacturer   5.                         professional
                                   (A)NDA # _________     
                                                          [_] user facility
- --------------------------------    IND #   _________
                                                          [_] company
6. If IND, protocol #               PLA #   __________        representative

                                    pre-1938  [_] yes     [_] distributor
- ---------------------------------
7. Type of report                   OTC                   [_] other:
   (check all that apply)           product   [_] yes
                                                              _____________
[_] 5-day   [_] 15-day              --------------------------------------------
                                    8. Adverse event terms(s)
[_] 10-day  [_] periodic

[_] initial [_] follow-up # _____

- ---------------------------------
9. Mfr. report number


- --------------------------------------------------------------------------------
E. Initial reporter
- --------------------------------------------------------------------------------
1. Name, address & phone number




- --------------------------------------------------------------------------------
2. Health professional?       3. Occupation           4. Initial reporter also
                                                         sent report to FDA

   [_] yes        [_] no                                 [_] yes [_] no [_] unk

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

FDA                     Submission of a report does not constitute an
Facsimile Form 3500A    admission that medical personnel, user facility,
                        distributor, manufacturer or product caused or
                        contributed to the event.


<PAGE>

                                                                   Exhibit 10.24


                              SUBLICENSE AGREEMENT
                     WITH RESPECT TO SLOAN-KETTERING LICENSE

                                     BETWEEN

                         PROGENICS PHARMACEUTICALS, INC.

                                       AND

                          BRISTOL-MYERS SQUIBB COMPANY

                                   DATED AS OF

                                 APRIL 15, 1997



[Note: Certain portions of this document have been marked "[XXX]" to 
indicate that confidentiality has been requested for this information. The 
confidential portions have been omitted and filed separately with the 
Securities and Exchange Commission.]

<PAGE>

                                TABLE OF CONTENTS

                                                                            Page
                                                                            ----

1.    DEFINITIONS .........................................................    1
      1.1      "Affiliate" ................................................    1
      1.2      "BCG" ......................................................    2
      1.3      "Compound" .................................................    2
      1.4      "Derivative" ...............................................    2
      1.5      "Distributor" ..............................................    2
      1.6      "Effective Date" ...........................................    2
      1.7      "End User" .................................................    2
      1.8      "FDA" ......................................................    2
      1.9      "First Commercial Sale" ....................................    2
      1.10     "GD2" ......................................................    2
      1.11     "Generic Product" ..........................................    2
      1.12     "GM2" ......................................................    2
      1.13     "GMK Vaccine" ..............................................    2
      1.14     "Government" ...............................................    3
      1.15     "KLH" ......................................................    3
      1.16     "MGV Vaccine" ..............................................    3
      1.17     "NDA" ......................................................    3
      1.18     "Net Sales" ................................................    3
      1.19     "Party" ....................................................    3
      1.20     "Person" ...................................................    3
      1.21     "PLA" ......................................................    3
      1.22     "QS-21" ....................................................    3
      1.23     "S-K Field" ................................................    3
      1.24     "S-K Licensed Patents" .....................................    4
      1.25     "S-K Licensed Technology" ..................................    4
      1.26     "S-K Products" .............................................    4
      1.27     "S-K Technical Information" ................................    4
      1.28     "Sub-sublicensee" ..........................................    5
      1.29     "Territory" ................................................    5
      1.30     "Third Party" ..............................................    5
      1.31     "Use" ......................................................    5
      1.32     "Valid Claim" ..............................................    5

2.    REPRESENTATIONS AND WARRANTIES OF PROGENICS .........................    5
      2.1      Representations and Warranties .............................    5

3.    GRANT OF RIGHTS .....................................................    6
      3.1      Sublicense Grant Under Sloan-Kettering/PROGENICS
               License Agreement ..........................................    6
      3.2      Sublicense Rights ..........................................    7
      3.3      BMS Rights under Sloan-Kettering/PROGENICS
               License Agreement ..........................................    8

4.    UPFRONT FEE; ROYALTY PAYMENTS .......................................    9
      4.1      Upfront Fee ................................................    9
      4.2      Royalty Payments ...........................................    9


                                       (1)
<PAGE>

                          TABLE OF CONTENTS (continued)

                                                                            Page
                                                                            ----

      4.3      Obligation to Pay Royalties ................................   15

5.    DILIGENCE OBLIGATIONS OF BMS ........................................   15
      5.1      Diligence Obligations ......................................   15

6.    PAYMENTS AND REPORTS ................................................   16
      6.1      Reports; Payments ..........................................   16
      6.2      Mode of Payment; Taxes .....................................   16
      6.3      Records Retention ..........................................   17
      6.4      Audit Request ..............................................   17
      6.5      Cost of Audit ..............................................   17
      6.6      No Non-Monetary Consideration for Sales ....................   17
          
7.    PATENT PROSECUTION; ENFORCEMENT; INFRINGEMENT .......................   18
      7.1      Patent Prosecution .........................................   18
      7.2      Patent Costs ...............................................   18
      7.3      Patent Enforcement .........................................   18
      7.4      Infringement Action by Third Parties .......................   19
         
8.    TERM; TERMINATION ...................................................   20
      8.1      Term .......................................................   20
      8.2      Acknowledgment of Termination Rights Under Sloan-
               Kettering/PROGENICS License Agreement ......................   20
      8.3      Breach by Either Party .....................................   20
      8.4      Effect of Termination ......................................   20
      8.5      Right to Sell Stock on Hand ................................   21
      8.6      Termination of Sublicenses .................................   21
      8.7      Accrued Rights: Surviving Obligations ......................   21
         
9.    ASSIGNABILITY .......................................................   22
      9.1      Non-Assignability ..........................................   22
      9.2      Assignability ..............................................   22

10.   MISCELLANEOUS .......................................................   22
      10.1     Relationship of Parties ....................................   22
      10.2     Force Majeure ..............................................   22
      10.3     Further Actions ............................................   22
      10.4     Notice .....................................................   22
      10.5     Use of Name ................................................   23
      10.6     Non-Solicitation ...........................................   24
      10.7     Marking ....................................................   24
      10.8     Costs and Expenses .........................................   24
      10.9     Manufacture in United States ...............................   24
      10.10    Waiver .....................................................   24
      10.11    Compliance with Law ........................................   24
      10.12    Severability ...............................................   25
      10.13    Amendment ..................................................   25


                                       (2)
<PAGE>

                          TABLE OF CONTENTS (continued)

                                                                            Page
                                                                            ----

      10.14    Sloan-Kettering/PROGENICS License Agreement ................   25
      10.15    Governing Law ..............................................   25
      10.16    Arbitration ................................................   25
      10.17    Counterparts ...............................................   26
      10.18    Descriptive Headings .......................................   26


                                EXHIBITS

                      Exhibit A           S-K Licensed Patents


                                      (3)
<PAGE>

                              SUBLICENSE AGREEMENT
                     WITH RESPECT TO SLOAN-KETTERING LICENSE

      THIS SUBLICENSE AGREEMENT WITH RESPECT TO SLOAN-KETTERING LICENSE (this
"Agreement") is dated as of April 15, 1997 between Progenics Pharmaceuticals,
Inc., a Delaware corporation, having offices at 777 Old Saw Mill River Road,
Tarrytown, New York 10591 ("PROGENICS"), and Bristol-Myers Squibb Company, a
Delaware corporation, having offices at P.O. Box 4000, Route 206 and Province
Line Road, Princeton, New Jersey 08543-4000, for and on behalf of itself and its
Affiliates ("BMS").

                             PRELIMINARY STATEMENTS

      A. PROGENICS has acquired a license to certain patents and technology
relating to the treatment of human cancers using vaccines pursuant to a license
agreement dated November 17, 1994 (the "Sloan-Kettering/PROGENICS License
Agreement") between PROGENICS and Sloan-Kettering Institute for Cancer Research,
a not-for-profit membership corporation of the State of New York
("Sloan-Kettering").

      B. BMS is interested in obtaining a worldwide sublicense to formulate,
manufacture, use and sell products using the patent rights and technology to
which PROGENICS has acquired a license from Sloan-Kettering, and PROGENICS
wishes to grant such rights to BMS, pursuant to the terms and conditions set
forth in this Agreement.

      C. It is anticipated that BMS, PROGENICS and Sloan-Kettering will enter
into a side letter agreement (the "Sloan-Kettering Letter Agreement") with
respect to this Agreement and the Sloan-Kettering/PROGENICS License Agreement,
and the rights and obligations of such parties hereunder and thereunder.

      NOW, THEREFORE, in consideration of the mutual covenants and agreements of
the Parties contained in this Agreement, the Parties agree as follows:

1.  DEFINITIONS.

      As used in this Agreement, the following terms will have those meanings
set forth in this Section 1 unless the context dictates otherwise.

      1.1 "Affiliate", with respect to any Party, shall mean any Person which,
directly or indirectly, controls, is controlled by, or is under common control
with, such Party. For these purposes, "control" shall refer to the possession,
directly or indirectly, of the power to direct the management or policies of a
Person or to veto any material decision relating to the management or policies
of a Person, in each case, whether through the ownership of equity
<PAGE>

participation, voting securities or beneficial interests, by contract, by
agreement, or otherwise.

      1.2 "BCG" shall mean bacille de Calmette et Guerin, a nonspecific immune
stimulant (cow tuberculosis) vaccine.

      1.3  "Compound" shall mean any of BCG, GM2, GD2, KLH and QS-21.

      1.4 "Derivative" shall mean a chemical substance derived from another
substance either directly or by modification or partial substitution.

      1.5 "Distributor" shall mean any Person engaged by BMS, or any agent or
representative of BMS, to distribute any S-K Product(s) either directly or
indirectly through other distributors.

      1.6 "Effective Date" shall mean the date first above written as the date
of this Agreement.

      1.7 "End User" shall mean any Person licensed or otherwise authorized to
Use S-K Product(s) for its own personal use, or any Person licensed to Use S-K
Product(s) in the regular conduct of its own business and not for licensing to
other Persons.

      1.8 "FDA" shall mean the United States Food and Drug Administration, or
the successor thereto.

      1.9 "First Commercial Sale" shall mean, in each country in the Territory,
the date that the S-K Product(s) are first sold, marketed or publicly made
available for sale. S-K Product(s) distributed or used for clinical trials or
experimental purposes only shall not be considered sold, marketed or made
publicly available and shall not establish the First Commercial Sale.

      1.10 "GD2" shall mean [XXX].

      1.11 "Generic Product" shall mean, on a country-by-country basis, an S-K
Product: (i) the manufacture, use or sale of which is not covered by a Valid
Claim in such country, and (ii) that is also marketed by an unlicensed Third
Party or Parties in such country, which Third Party or Parties have, in the
aggregate, at least [XXX] in such country, as measured by IMS.

      1.12 "GM2" shall mean [XXX].

      1.13 "GMK Vaccine" shall mean that certain S-K Product composed of GM2
conjugated to KLH and combined with QS-21.


                                       -2-
<PAGE>

      1.14  "Government" means the Federal Government of the United States of
America.

      1.15  "KLH" shall mean keyhole limpet hemocyanin.

      1.16 "MGV Vaccine" shall mean that certain S-K Product composed of GM2
conjugated to KLH and combined with GD2 conjugated to KLH and further combined
with QS-21.

      1.17  "NDA" shall mean New Drug Application as defined by the FDA.

      1.18 "Net Sales" shall mean the gross amount [XXX]. Such amounts shall be 
determined from the books and records of BMS, its Affiliates or 
Sub-sublicensees, maintained in accordance with the accounting principles used 
by such entity, consistently applied.

      1.19 "Party" shall mean PROGENICS or BMS and, when used in the plural,
shall mean PROGENICS and BMS.

      1.20 "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, or any organization which can exercise independent legal standing.

      1.21 "PLA" shall mean a Product License Application filed with the FDA.

      1.22 "QS-21" shall mean the [XXX].

      1.23 "S-K Field" shall mean, and is limited to, the practice of the S-K
Licensed Patents and S-K Technical Information for the treatment or prevention
of neoplastic human disease or the treatment of human cancer with any of the
following: [XXX]


                                       -3-
<PAGE>

[XXX]

      1.24  "S-K Licensed Patents" shall mean:

            (a) The following patent applications and patents relating to
ganglioside vaccines, intermediates or methods of producing them, or methods of,
or compositions using, them which are owned by or licensed to PROGENICS [XXX]: 
(i) [XXX] all patents issuing therefrom and all divisions, continuations, 
patents issuing therefrom and all divisions, continuations, reissues,
substitutes, and extensions thereof and the foreign equivalents thereof; and
(ii) all patents and patent applications, whether filed before or after the
effective date of the Sloan-Kettering/PROGENICS License Agreement, which claim
priority under 35 U.S.C. ss. 119 or the benefit of the filing date under 35
U.S.C. ss. 120 of the patent applications and patents of clause (i), but only to
the extent of subject matter in such applications and patents for which priority
or benefit is claimed; and

            (b) Any developments related to or arising out of the subject matter
described in Section 1.24(a) which are dominated by the patent applications or
patents described in Section 1.24(a) or [XXX].

      1.25 "S-K Licensed Technology" shall mean the S-K Licensed Patent(s) and
the S-K Technical Information.

      1.26 "S-K Products" shall mean any and all products which fall within the
S-K Field and which: (i) would infringe a claim of any S-K Licensed Patent(s),
but for this Agreement and the Sloan-Kettering/PROGENICS License Agreement, or
(ii) are produced or used using a process or method that would infringe, but for
this Agreement and the Sloan-Kettering/PROGENICS License Agreement, a claim of
any S-K Licensed Patent, or (iii) were developed using S-K Technical
Information. S-K Products shall include, without limitation, the GMK Vaccine and
the MGV Vaccine.

      1.27 "S-K Technical Information" shall mean unpublished research and
development information, unpatented inventions, know-how, trade secrets, and
technical data in the possession of Sloan-Kettering at the effective date of the
Sloan-Kettering/PROGENICS License Agreement which are needed to produce or gain
government approvals to market S-K Product(s) and which Sloan-Kettering has the
right to and will provide to PROGENICS upon request. However, S-K Technical
Information does not include patient names. Information and materials shall no
longer be


                                       -4-
<PAGE>

considered to be S-K Technical Information if such information or materials
cease to be Confidential Information.

      1.28 "Sub-sublicensee" shall mean any Person, not an Affiliate of BMS,
which is licensed by BMS, pursuant to the authority granted in this Agreement,
which has rights to S-K Licensed Technology beyond those rights commonly granted
to an End User.

      1.29  "Territory" shall mean the entire world.

      1.30 "Third Party" shall mean any Person who or which is neither a Party
nor an Affiliate of a Party.

      1.31 "Use" shall mean any form of practice or utilization of the S-K
Licensed Technology, or any portion thereof.

      1.32 "Valid Claim" shall mean a claim of any S-K Licensed Patent which has
not been held invalid or unenforceable by final decision of a court or other
governmental agency of competent jurisdiction, unappealed or unappeased within
the time allowed for appeal, and which is not admitted to be invalid or
unenforceable through reissue, disclaimer or otherwise.

2.  REPRESENTATIONS AND WARRANTIES OF PROGENICS.

      2.1  Representations and Warranties. PROGENICS represents and warrants to
BMS as of the Effective Date:

            (a)  The Sloan-Kettering/PROGENICS License Agreement is in full
force and effect and has not been modified or amended;

            (b) To the best of PROGENICS's knowledge, neither Sloan-Kettering
nor PROGENICS is in default under, and neither party claims or has grounds upon
which to claim the other party is in default under, the
Sloan-Kettering/PROGENICS License Agreement;

            (c) To the best of PROGENICS's knowledge, the rights Sloan-Kettering
has licensed to PROGENICS pursuant to the Sloan-Kettering/PROGENICS License
Agreement were not and are not subject to any restrictions or limitations except
as set forth in the Sloan-Kettering/PROGENICS License Agreement;

            (d) To the best of PROGENICS's knowledge, Sloan-Kettering has not
accepted funding from any non-governmental parties which would diminish
PROGENICS's rights to technology under the Sloan-Kettering/PROGENICS License
Agreement;

            (e) The milestones set forth in Sections 5.01(a), (b) and (e) of the
Sloan-Kettering/PROGENICS License Agreement have been fully satisfied by
PROGENICS as of the Effective Date; and


                                       -5-
<PAGE>

            (f) Attached hereto as Exhibit A is a true and complete list of all
patents and patent applications comprising the S-K Licensed Patents as of the
Effective Date

3.  GRANT OF RIGHTS.

      3.1  Sublicense Grant Under Sloan-Kettering/PROGENICS License Agreement.

            (a) Subject to the terms and conditions of this Agreement, PROGENICS
hereby grants to BMS an exclusive (including as to PROGENICS) sublicense, under
the Sloan-Kettering License Agreement, to use the S-K Licensed Patents and the
S-K Technical Information to make, have made, use, sell, have sold and develop
S-K Products in the S-K Field throughout the Territory. No license under the S-K
Licensed Patents and S-K Technical Information is granted, and no license should
be implied, with respect to activities of BMS outside the S-K Field.

            (b) The sublicense granted to S-K Licensed Patents pursuant to
Section 3.1(a) shall be exclusive, with the right to grant sublicenses as
provided in Section 3.2. The sublicense granted to S-K Technical Information
pursuant to Section 3.1(a) shall be exclusive for the S-K Field with the right
to grant sublicenses as provided in Section 3.2.

            (c) The sublicense granted in this Section 3 shall be granted to
Affiliates of BMS, effective five days after receipt of written notification
from BMS by PROGENICS thereof.

            (d) Without limiting the foregoing sublicense grants, PROGENICS
agrees that this grant will extend to and authorize the manufacture, sale, lease
or other transfer of S-K Products through an Affiliate or a Distributor and
shall authorize End Users' Use of S-K Products transferred by PROGENICS to BMS's
Affiliates or Distributors.

            (e) All rights granted in this Agreement are expressly granted
subject to the rights of the Government pursuant to 35 U.S.C. ss. 200 et seq.,
as amended, and the implementing regulations, and such rights are specifically
reserved by this Agreement to the Government. If Sloan-Kettering or PROGENICS is
required to grant licenses pursuant to the statutory and regulatory requirements
referred to in this Section 3.1(e), or if the sublicense granted to BMS under
this Agreement is otherwise modified or limited by the Government pursuant to
such requirements, PROGENICS and BMS shall negotiate in good faith a reduction
of the sublicense fees and royalties payable hereunder and such other amendments
of this Agreement as may be appropriate under the circumstances.


                                       -6-
<PAGE>

            (f) Notwithstanding the exclusive field sublicense granted herein,
BMS hereby acknowledges that: (i) Sloan-Kettering has specifically reserved the
rights to manufacture, or use the S-K Licensed Patents, S-K Products and S-K
Technical Information for its own internal purposes, including continuing
research, development, testing, clinical use and all other internal uses; (ii)
Sloan-Kettering may have the S-K Products manufactured by Third Parties solely
for Sloan-Kettering's internal use provided any such Third Party agrees in
writing (a) not to use the S-K Technical Information except for such purpose and
(b) not to disclose the S-K Technical Information to others; and (iii)
Sloan-Kettering also has reserved the right to permit other Persons to use the
S-K Licensed Patents, S-K Products, and S-K Technical Information solely for
academic research purposes provided such other Persons agree in writing (x) to
use the same only for academic research purposes, (y) not to provide the same to
other entities or individuals and (z) not to disclose the S-K Technical
Information to others.

            (g) Provided Sloan-Kettering's Affiliate(s) is capable and accepts,
BMS hereby grants to Sloan-Kettering's Affiliate(s) a right of first refusal to
function as a site at which the clinical tests or trials of any S-K products are
performed. Such right of first refusal shall mean that BMS shall request a
proposal from Sloan-Kettering setting forth the procedures which Sloan-Kettering
would follow in the tests and the associated costs. If BMS decides not to
accept Sloan-Kettering's proposal, then BMS may only contract with a clinical
test site(s) whose proposal is more favorable (taken as a whole) to BMS than
that proposed by Sloan-Kettering.

      3.2  Sublicense Rights.

            (a) BMS shall have the right to grant sublicenses to its Affiliates
of the sublicense granted to BMS herein, provided that: (i) BMS shall guarantee
and be responsible for the making of all payments due, and the making of reports
under this Agreement, by reason of sales of any S-K Products by its Affiliates
and their compliance with all applicable terms of this Agreement (including the
applicable terms of the Sloan-Kettering/PROGENICS License Agreement); and (ii)
each Affiliate agrees in writing to keep books and records and permit PROGENICS
to review such books and records pursuant to the relevant provisions and to
observe all other applicable terms of this Agreement. No consent or approval of
PROGENICS shall be required in connection with the granting of such sublicenses.

            (b) BMS shall have the right to grant sublicenses to
Sub-sublicensees of the sublicense granted to BMS herein, except that BMS does
not have the right to grant such sublicenses with respect to the United States,
provided that: (i) PROGENICS shall have consented to such sublicense, which
approval shall not be


                                       -7-
<PAGE>

unreasonably withheld (it will be reasonable for PROGENICS to withhold consent
if PROGENICS determines that the capabilities of the proposed Sub-sublicensee
are not comparable to BMS's capabilities in the country or countries to be
sublicensed); (ii) BMS shall guarantee and be responsible for the making of all
payments due, and the making of reports under this Agreement, by reason of sales
of any S-K Products by its Sub-sublicensees and their compliance with all
applicable terms of this Agreement (including the applicable terms of the
Sloan-Kettering/PROGENICS License Agreement); and (iii) each Sub-sublicensee
agrees in writing to keep books and records and permit PROGENICS to review such
books and records pursuant to the relevant provisions and to observe all other
applicable terms of this Agreement.

            (c) BMS hereby unconditionally guarantees the performance of any of
its Affiliates and Sub-sublicensees hereunder. In the event of a breach by an
Affiliate or Sub-sublicensee in the observance of applicable terms of this
Agreement, PROGENICS shall be entitled to proceed against either such Affiliate
or Sub-sublicensee or directly against BMS, as PROGENICS may determine in its
sole discretion, to enforce this Agreement.

      3.3 BMS Rights under Sloan-Kettering/PROGENICS License Agreement.
PROGENICS agrees that, with respect to the Sloan-Kettering/PROGENICS License
Agreement:

            (a)  PROGENICS will diligently fulfill all of its obligations
thereunder, to the extent such obligations have not been delegated to BMS;

            (b) PROGENICS shall not enter into any subsequent agreement with
Sloan-Kettering which modifies or amends the Sloan-Kettering/PROGENICS License
Agreement in a way which is deleterious to the rights of BMS under this
Agreement;

            (c) PROGENICS shall not terminate the Sloan-Kettering/PROGENICS
License Agreement, in whole or in part, directly or indirectly, without the
prior written consent of BMS, which shall not be unreasonably withheld in the
event that Sloan-Kettering is in material default under the terms thereof at the
time PROGENICS seeks to make such exercise;

            (d) PROGENICS shall promptly furnish BMS with copies of all reports
it receives from Sloan-Kettering which relate to the subject of this Agreement;

            (e) PROGENICS shall promptly furnish BMS with copies of all reports
PROGENICS furnishes to Sloan-Kettering which relate to the subject of this
Agreement, including without limitation all correspondence of any kind with
respect to the filing, prosecution or maintenance of the S-K Licensed Patents in
any jurisdiction;


                                       -8-
<PAGE>

            (f) PROGENICS shall promptly deliver to Sloan-Kettering's patent
counsel all of BMS's comments with respect to the filing, prosecution or
maintenance of the S-K Licensed Patents in any jurisdiction, including without
limitation requests for filing for foreign protection, as if such comments were
comments of PROGENICS; and

            (g) PROGENICS shall furnish to BMS copies of all notices received by
PROGENICS relating to alleged breaches or defaults by PROGENICS of its
obligations under the Sloan-Kettering/PROGENICS License Agreement within three
business days of PROGENICS's receipt thereof and, provided that PROGENICS cannot
or chooses not to cure or otherwise resolve such alleged breaches or defaults,
PROGENICS shall allow BMS, in BMS's sole discretion, to cure or otherwise
resolve such alleged breaches or defaults in order to preserve BMS's rights
under this Agreement.

4.  UPFRONT FEE; ROYALTY PAYMENTS.

      4.1 Upfront Fee. As consideration to PROGENICS for the issuance of the
sublicense and other rights to BMS under this Agreement, BMS shall pay to
PROGENICS the sum of: [XXX]. Such up-front fee shall be paid upon the execution
of this Agreement by both Parties. Such sum shall be non-refundable.

      4.2 Royalty Payments. As consideration to PROGENICS for the sublicense and
other rights granted to BMS under this Agreement, during the term of this
Agreement, BMS shall pay to PROGENICS a royalty on Net Sales of any S-K Product
commencing on the First Commercial Sale of such S-K Product by BMS, its
Affiliates or its Sub-sublicensees as follows:

            (a)  With respect to the GMK Vaccine:

                  (i) With respect to those countries in the Territory where
such S-K Product is covered by a Valid Claim in such countries:

                        (A) [XXX] of the Net Sales of such S-K Product in such 
                  countries for any calendar year until royalties relating to 
                  all S-K Products throughout the Territory in the amount of 
                  [XXX] have accrued and are payable by BMS to PROGENICS in such
                  calendar year; and

                        (B) After royalties relating to all S-K Products
                  throughout the Territory in the amount of [XXX] have accrued 
                  and are payable by


                                       -9-
<PAGE>

                  BMS to PROGENICS in such calendar year, [XXX] of any further
                  Net Sales of such S-K Product in such countries until Net
                  Sales of such S-K Product throughout the Territory in such
                  calendar year equal [XXX]; and

                        (C) After Net Sales of such S-K Product throughout the
                  Territory in such calendar year exceed [XXX] of any further
                  Net Sales of such S-K Product in such countries until the end
                  of such calendar year.

                  (ii) With respect to those countries in the Territory where
such S-K Product is not covered by, or is no longer covered by, a Valid Claim in
such countries (unless such S-K Product has become a Generic Product in any such
country, in which case subparagraph (iii) below shall apply):

                        (A) [XXX] of the Net Sales of such S-K Product in such
                  countries for any calendar year until Net Sales of such S-K
                  Product throughout the Territory in such calendar year equal
                  [XXX]; and

                        (B) After Net Sales for such S-K Product throughout the
                  Territory in such calendar year exceed [XXX] of any further
                  Net Sales of such S-K Product in such countries until the end
                  of such calendar year.

                  (iii) With respect to those countries in the Territory where
such S-K Product is a Generic Product:

                        (A) [XXX] of the Net Sales of such S-K Product in such
                  countries for any calendar year until Net Sales of such S-K
                  Product throughout the Territory in such calendar year equal
                  [XXX]; and

                        (B) After Net Sales for such S-K Product throughout the
                  Territory in such calendar year exceed [XXX] of any further
                  Net Sales of such S-K Product in such countries until the end
                  of such calendar year.


                                      -10-
<PAGE>

                  (iv) Royalties shall be paid at the royalty rates set forth in
Sections 4.2(a)(i)(A), 4.2(a)(ii)(A) and 4.2(a)(iii)(A) through the end of the
calendar quarter preceding the calendar quarter in which annual Net Sales in all
countries throughout the Territory first exceed [XXX] in any year; provided,
however, that in the calendar quarter in which royalties relating to all S-K
Products throughout the Territory in the aggregate amount of at least [XXX] have
accrued and are payable by BMS to PROGENICS for the calendar year, and in each
subsequent calendar quarter in that calendar year, royalties under Section
4.2(a)(i) shall be paid at the royalty rate set forth in Section 4.2(a)(i)(B) in
lieu of the royalty rate set forth in Section 4.2(a)(i)(A). Royalties shall be
paid at the royalty rates set forth in Sections 4.2(a)(i)(C), 4.2(a)(ii)(B) and
4.2(a)(iii)(B) for the calendar quarter in which annual Net Sales in all
countries throughout the Territory first exceed [XXX] in any year, and for each
calendar quarter in such year thereafter other than the last calendar quarter of
such year. Following the end of the last calendar quarter of each year, the
total amount of royalties actually due for such year shall be calculated as
provided in Section 4.2(a)(v), and such amount of royalties shall be paid,
reduced by the total amount of royalties paid with respect to such S-K Product
throughout the Territory for the first three calendar quarters of such year. The
calculation of the amount to be paid with respect to the fourth calendar quarter
of each year shall be included on the royalty report for such calendar quarter.
In the event that BMS has paid more royalties during the first three calendar
quarters of any year than BMS owes for the entire year, BMS shall be entitled to
a credit, equal to the amount of such excess royalties, paid, to be applied
against [XXX] of accrued royalties until the entire credit has been used.

                  (v) The total amount of royalties actually due for each year
under this Section 4.2(a) shall be calculated as follows:

                        (A) The royalty rate set forth in Section 4.2(a)(i)(A)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(1), x Y(1)/Z x [XXX]/W;


                        (B) The royalty rate set forth in Section 4.2(a)(i)(B)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(1) x Y(1)/Z x 
                  [1-[XXX]/W];

                        (C) The royalty rate set forth in Section 4.2(a)(i)(C)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(2) x Y(1)/Z;


                                      -11-
<PAGE>

                        (D) The royalty rate set forth in Section 4.2(a)(ii)(A)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(1) x Y(2)/Z;

                        (E) The royalty rate set forth in Section 4.2(a)(ii)(B)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(2) x Y(2)/Z;

                        (F) The royalty rate set forth in Section 4.2(a)(iii)(A)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(1) x Y(3)/Z; and

                        (G) The royalty rate set forth in Section 4.2(a)(iii)(B)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X(2) x Y(3)/Z;

            Where:

            W       =   the sum of the amount of the royalties that are
                        generated by the first [XXX] of Net Sales of each S-K
                        Product which have accrued and are payable by BMS to
                        PROGENICS for any calendar year with respect to each S-K
                        Product included in all S-K Products throughout the
                        Territory; provided that if the foregoing sum of
                        royalties is less than [XXX] then W shall equal [XXX]

            X(1)    =   smaller of: (i) the actual annual Net Sales of such S-K
                        Product throughout the Territory for such year; or (ii)
                        [XXX]

            X(2)    =   the actual annual Net Sales of such S-K Product
                        throughout the Territory for such year in excess of
                        [XXX]

            Y(1)    =   the annual Net Sales of such S-K Product for such year
                        in all countries when Section 4.2(a)(i) applies

            Y(2)    =   the annual Net Sales of such S-K Product for such year
                        in all countries when Section 4.2(a)(ii) applies

            Y(3)    =   the annual Net Sales of such S-K Product for such year
                        in all countries when Section 4.2(a)(iii) applies


                                      -12-
<PAGE>

            Z     =     the annual Net Sales of such S-K Product for such year
                        in all countries in the Territory

            (b)  With respect to the MGV Vaccine and any other S-K
Products:

                  (i) With respect to those countries in the Territory where
such S-K Product is covered by a Valid Claim in such countries:

                        (A) [XXX] of the Net Sales of such S-K Product in such
                  countries for any calendar year until royalties relating to
                  all S-K Products throughout the Territory in the amount of
                  [XXX] have accrued and are payable by BMS to PROGENICS in such
                  calendar year; and

                        (B) After royalties relating to all S-K Products
                  throughout the Territory in the amount of [XXX] have accrued
                  and are payable by BMS to PROGENICS in such calendar year,
                  [XXX] of any further Net Sales of such S-K Product in such
                  countries until the end of such calendar year.

                  (ii) With respect to those countries in the Territory where
such S-K Product is not covered by, or is no longer covered by, a Valid Claim in
such countries (unless such S-K Product has become a Generic Product in any such
country, in which case subparagraph (iii) below shall apply), [XXX] of the Net 
Sales of such S-K Product in such countries for any calendar year.

                  (iii) With respect to those countries in the Territory where
such S-K Product is a Generic Product, [XXX] of the Net Sales of such S-K 
Product in such countries for any calendar year.

                  (iv) Royalties shall be paid at the royalty rate set forth in
Section 4.2(b)(i)(A) through the end of the calendar quarter preceding the
calendar quarter in which royalties relating to all S-K Products throughout the
Territory in the aggregate amount of at least [XXX] have accrued and are 
payable by BMS to PROGENICS for the calendar year. Royalties shall be paid at
the royalty rate set forth in Section 4.2(b)(i)(B) for the calendar quarter in
which royalties relating to all S-K Products throughout the Territory in the
aggregate amount of at least [XXX] have accrued and are payable by BMS to
PROGENICS for the calendar year, and for each calendar quarter in such year
thereafter other than the last calendar quarter of such year. Following the end
of the last calendar quarter of each year, the total amount of royalties


                                      -13-
<PAGE>

actually due for such year shall be the aggregate of the amounts for the entire
year, calculated as provided in Sections 4.2(b)(ii), (iii) and (v), and such
amount of royalties shall be paid, reduced by the total amount of royalties paid
with respect to such S-K Product throughout the Territory for the first three
calendar quarters of such year. The calculation of the amount to be paid with
respect to the fourth calendar quarter of each year shall be included on the
royalty report for such calendar quarter. In the event that BMS has paid more
royalties during the first three calendar quarters of any year than BMS owes for
the entire year, BMS shall be entitled to a credit, equal to the amount of such
excess royalties paid, to be applied against [XXX] of accrued royalties until 
the entire credit has been used.

                  (v) The total amount of royalties actually due for each year
under this Section 4.2(b)(i) shall be calculated as follows:

                        (A) The royalty rate set forth in Section 4.2(b)(i)(A)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X x [XXX]/W; and

                        (B) The royalty rate set forth in Section 4.2(b)(i)(B)
                  shall be applied to that amount of Net Sales of such S-K
                  Product determined under the formula X x [1-[XXX]/W];

            Where:

            W     =     the sum of the amount of the royalties that are
                        generated by the first [XXX] of Net Sales of each S-K
                        Product which have accrued and are payable by BMS to
                        PROGENICS for any calendar year with respect to each S-K
                        Product included in all S-K Products throughout the
                        Territory; provided that if the foregoing sum of
                        royalties is less than [XXX], then W shall equal [XXX]

            X     =     the actual annual Net Sales of such S-K Product
                        throughout the Territory for such year

            (c) The royalty rates applicable to S-K Products not covered by a
Valid Claim pursuant to Sections 4.2(a)(ii) and 4.2(b)(ii), respectively, shall
apply to Net Sales in any country commencing with the calendar quarter during
which such S-K Product is first not covered by a Valid Claim in such country.

            (d)  The royalty rates applicable to Generic Products pursuant to
Sections 4.2(a)(iii) and 4.2(b)(iii), respectively,


                                      -14-
<PAGE>

shall apply to Net Sales in any country commencing with the calendar quarter
during which such S-K Product first becomes a Generic Product in such country.

      4.3 Obligation to Pay Royalties. The obligation to pay royalties to
PROGENICS under Section 4.2 is imposed only once with respect to the same unit
of S-K Product regardless of the number of S-K Licensed Patents pertaining
thereto. BMS shall only be entitled to a credit against royalties or a reduction
of the royalty rate once with respect to any S-K Product in any country pursuant
to any provision in this Agreement. There shall be no obligation to pay
royalties to PROGENICS under Section 4.2 on sales of S-K Products among BMS, its
Affiliates and Sub-sublicensees, but in such instances the obligation to pay
royalties shall arise upon the sale by BMS, its Affiliates or Sub-sublicensees
to Third Parties. Payments due under Section 4.2 shall be deemed to accrue when
S-K Products are shipped or billed, whichever event shall first occur. In the
instance where BMS, its Affiliates or Sub-sublicensees use the S-K Product or
provide it as part of some other service or product, a royalty shall be due to
PROGENICS at the time such S-K Product is used or provided based on a Net Sales
amount equal to the price at which BMS or its Affiliate or Sub-sublicensee sell
such S-K Product to Third Parties in the country in which the S-K Product was
used or provided.

5.  DILIGENCE OBLIGATIONS OF BMS.

      5.1 Diligence Obligations. BMS shall use its best reasonable efforts to
develop and market S-K Product(s) for commercial sale and distribution
throughout the Territory pursuant to this Agreement, and to such end, BMS, its
Affiliates or its Sub-sublicensees shall achieve the following objectives in
accordance with the following schedule:

            (i)  [XXX].

            (ii) [XXX].

      The Parties acknowledge that, subject to certain limitations set forth in
Section 5.01 of the Sloan-Kettering/PROGENICS License Agreement, failure to
achieve these objectives shall entitle Sloan-Kettering to terminate the license
granted under the Sloan-Kettering/PROGENICS License Agreement and, thereby, the
license granted under this Agreement. PROGENICS shall not unreasonably withhold
its consent to, and shall use all reasonable efforts to obtain the consent of
Sloan-Kettering to, any revision in the preceding schedule requested in writing
by BMS and supported by evidence of technical difficulties or delays in the
clinical studies or regulatory process that could not have been reasonably


                                      -15-
<PAGE>

avoided. Notwithstanding the foregoing, the Parties acknowledge that
Sloan-Kettering shall not have the right to terminate the license granted under
the Sloan-Kettering/PROGENICS License Agreement, and therefore PROGENICS shall
not have a right to terminate the license granted under this Agreement, for the
failure of BMS to meet a goal if such failure is a result of (i) causes beyond
BMS's direct control; (ii) Sloan-Kettering's or PROGENICS's failure to meet its
obligations hereunder; (iii) infringement of Third Party patents; or (iv)
actions or inactions of a federal or state agency whose approval is required for
commercial sales.

      The Parties further acknowledge and agree that the milestones contained in
this Section 5.1 were established on the assumption that the milestones would
apply to development of the GMK Vaccine. In the event that development of the
GMK Vaccine is terminated due to safety or efficacy reasons, the parties agree
that the milestones set forth in this Section 5.1 shall not apply and the
Parties will negotiate in good faith to establish new milestones.

6.  PAYMENTS AND REPORTS.

      6.1 Reports; Payments. Except as otherwise specifically provided in this
Agreement, all payments due under this Agreement shall be paid quarterly within
50 days after the end of each calendar quarter. Each such payment for running
royalties shall be accompanied by a statement, S-K Product-by-S-K Product and
country-by-country, of the amount of Net Sales during such quarter and the
amount of royalties due on such Net Sales and, with respect to the last calendar
quarter of each year, such report shall include the calculation of the
adjustments referred to in Sections 4.2(a)(iv) and 4.2(b)(iv).

      6.2 Mode of Payment; Taxes. All payments due under this Agreement shall be
paid by wire transfer of funds to an account at PROGENICS's designated bank in
New York, New York, and shall be paid in U.S. Dollars, calculated at BMS's
customary internal corporate monthly exchange rates for the last month of the
calendar quarter for which remittance is made for royalties. Such payments shall
be free of any taxes, charges, or remittance fees, except for income tax levied
upon or required to be withheld and paid by BMS, its Affiliates or its
Sub-sublicensees for the account of PROGENICS. BMS shall provide PROGENICS
appropriate receipts of payment of such withholding taxes or other proof
thereof. For each month and each currency, BMS's customary internal corporate
monthly exchange rate shall equal the arithmetic average of the daily exchange
rates (obtained as described below) during the period from (i) the 20th day of
the preceding month (or, if such 20th day is not a business day, the immediately
preceding business day) through (ii) the 19th day of the current month (or, if
such 19th day is not a business day, the immediately preceding business day);
each daily exchange rate shall be obtained from the Reuters Daily Rate Report


                                      -16-
<PAGE>

or The Wall Street Journal, Eastern U.S. Edition, or, if not so available, as
furnished by BMS's local Affiliates.

      6.3 Records Retention. BMS and its Affiliates and Sub-sublicensees shall
keep accurate records of all operations affecting payments hereunder, and shall
permit PROGENICS or its duly authorized agent to inspect all such records and to
make copies of or extracts from such records during regular business hours
throughout the term of this Agreement and for a reasonable period of not less
than three (3) years thereafter.

      6.4 Audit Request. At the request and expense of PROGENICS, BMS and its
Affiliates and Sub-sublicensees shall permit PROGENICS or an independent,
certified public accountant appointed by PROGENICS and reasonably acceptable to
BMS, at reasonable times and upon reasonable notice, to examine those records as
may be necessary to: (i) determine the correctness of any report or payment made
under this Agreement; or (ii) obtain all information as to Net Sales and the
royalties payable for any calendar quarter. If an accountant is used, said
accountant shall not disclose to PROGENICS any information other than
information relating to said reports, royalties, and payments. Results of any
such examination shall be made available to both Parties.

      6.5 Cost of Audit. PROGENICS shall bear the full cost of the performance
of any such audit except as hereinafter; set forth. If, as a result of any
inspection of the books and records of BMS, its Affiliates or its
Sub-sublicensees, it is shown that BMS's payments under this Agreement were less
than the amount which should have been paid, then BMS shall make all payments
required to be made to eliminate any discrepancy revealed by said inspection
within 30 days after PROGENICS's demand therefor, plus interest at the prime
rate from the date payment should have been made. Furthermore, if the payments
were less than the amount which should have been paid by an amount in excess of
five percent of the payments actually made during the period in question, BMS
shall also reimburse PROGENICS for the costs of such audit in addition to the
payment required to be made to eliminate any discrepancy.

      6.6 No Non-Monetary Consideration for Sales. Without the prior written
consent of PROGENICS, BMS and its Affiliates and Sub-sublicensees shall not
accept or solicit any non-monetary consideration in the sale of S-K Products
other than as would be reflected in Net Sales. The use by BMS and its Affiliates
and Sub-sublicensees of commercially reasonable amounts of S-K Products for
clinical trials and promotional sampling shall not violate this provision.


                                      -17-
<PAGE>

7.  PATENT PROSECUTION; ENFORCEMENT; INFRINGEMENT.

      7.1 Patent Prosecution. BMS acknowledges and agrees that the S-K Licensed
Patents will continue to be prosecuted (in the case of patent applications) and
maintained (in the case of patents) by Sloan-Kettering or PROGENICS. PROGENICS
agrees that the S-K Licensed Patents shall be prosecuted and/or maintained in
accordance with the Sloan-Kettering/PROGENICS License Agreement, and, to the
extent permitted thereunder, with diligence the same as or greater than is used
for PROGENICS's own patents and patent applications. To the extent that
PROGENICS has the right to do so, PROGENICS shall not permit any S-K Licensed
Patent to be abandoned.

      7.2 Patent Costs. BMS shall, from time to time, upon invoice from
PROGENICS, promptly reimburse PROGENICS for all out-of-pocket costs and expenses
incurred in connection with the prosecution and maintenance of the S-K Licensed
Patents including amounts payable by PROGENICS to Sloan-Kettering therefor as
required by the Sloan-Kettering/PROGENICS License Agreement.

      7.3  Patent Enforcement.

            (a) Each Party shall inform the other Party promptly in writing of
any alleged infringement of any S-K Licensed Patent by a third party of which it
shall have knowledge, and provide any available evidence of infringement.

            (b) BMS acknowledges and agrees that PROGENICS shall have the right
to defend the S-K Licensed Patents against infringement or interference by other
parties in whole or in part in the S-K Field in any country in which an S-K
Licensed Patent is in effect hereunder, including by bringing any legal action
for infringement or defending any counterclaim of invalidity or action of a
third party for declaratory judgment of non-infringement or interference
(however, as between PROGENICS and BMS, BMS shall have the right, but not the
obligation, to prosecute at its own expense any infringement of the S-K Licensed
Patents in the S-K Field). Sloan-Kettering agrees to join as a party plaintiff
in any such lawsuit initiated by PROGENICS and to cooperate with PROGENICS in
PROGENICS's prosecution, if requested by PROGENICS, with all reasonable costs,
attorney fees, and expenses to be paid by PROGENICS.

            (c) BMS acknowledges and agrees that, in the event that PROGENICS
shall undertake the enforcement of the S-K Licensed Patents by litigation,
PROGENICS may withhold [XXX] of the payments otherwise thereafter due
Sloan-Kettering and apply the same toward reimbursement of up to [XXX] of
PROGENICS's expenses, including reasonable attorneys' fees, in connection
therewith. Any recovery of damages by PROGENICS for each such suit shall be
applied first in satisfaction of any unreimbursed expenses and legal fees of
PROGENICS relating to such suit, and next toward reimbursement of


                                      -18-
<PAGE>

Sloan-Kettering for any payments past due or withheld and applied pursuant to
Section 10 of the Sloan-Kettering/PROGENICS License Agreement. The balance
remaining from any such recovery shall be retained by PROGENICS. (As between BMS
and PROGENICS, from the remaining balance, BMS shall be entitled to
reimbursement of expenses incurred by BMS in connection with such suit, and the
balance remaining from any such recovery shall be divided as follows: [XXX] to 
BMS and the remaining [XXX] to PROGENICS.)

            (d) BMS acknowledges and agrees that, under the Sloan-Kettering
License Agreement, if PROGENICS does not institute suit for infringements within
90 days of receipt of written notice from Sloan-Kettering of Sloan-Kettering's
desire to bring suit for infringement in its own name and on its own behalf,
then Sloan-Kettering may, at its own expense, bring suit or take any other
appropriate action. [XXX] shall be entitled to recovery of damages resulting 
from any lawsuit brought by [XXX] to enforce any S-K Licensed Patent, pursuant 
to Sloan-Kettering/PROGENICS License Agreement.

            (e) BMS acknowledges that the Sloan-Kettering/PROGENICS License
Agreement also provides that neither party may settle with any infringer without
the prior approval of the other party if such settlement would affect the rights
of the other party under the S-K Licensed Patents. (As between PROGENICS and
BMS, PROGENICS agrees to defer to BMS any reasonable objection that BMS may have
to any such settlement, consent judgment or final disposition.)

      7.4  Infringement Action by Third Parties.

            (a) Each Party shall promptly notify the other in writing in the
event that a third party shall bring a claim of infringement against either
Party, either in the United States or in any foreign country in which there is
an S-K Licensed Patent.

            (b) BMS acknowledges and agrees that PROGENICS, in its own name and
at its sole expense, shall have the first right to defend the S-K Licensed
Patents and may compromise, settle or otherwise pursue such defense in such a
manner and on such terms as PROGENICS shall see fit. (However, as between
PROGENICS and BMS, BMS shall have the first right, but not the obligation, to
defend, at its own expense, the S-K Licensed Patents in the S-K Field.)

            (c) BMS acknowledges and agrees that, in the event that PROGENICS
shall undertake such defense, PROGENICS may withhold [XXX] of the payments
otherwise thereafter due Sloan-Kettering and apply the same toward reimbursement
of PROGENICS's expenses, including reasonable attorneys' fees, in connection
therewith. Any recovery of damages by PROGENICS for each such suit shall be
applied first in satisfaction of any unreimbursed expenses and legal fees of
PROGENICS relating to such suit, and next toward


                                      -19-
<PAGE>

reimbursement of Sloan-Kettering for any payments past due or withheld and
applied pursuant to Section 10 of the Sloan-Kettering/PROGENICS License
Agreement. The balance remaining from any such recovery shall be retained by
PROGENICS.

8.  TERM: TERMINATION.

      8.1 Term. This Agreement shall commence as of the Effective Date of this
Agreement and, unless sooner terminated as provided hereunder, shall terminate
upon the expiration of the last to expire of the S-K Licensed Patents included
herein, or upon the abandonment of the last to be abandoned of any patent
applications included herein, or 15 years from the date of the First Commercial
Sale, whichever is later, unless the Sloan-Kettering/PROGENICS License Agreement
is sooner terminated, pursuant to the terms thereof.

      8.2 Acknowledgment of Termination Rights Under Sloan-Kettering/PROGENICS
License Agreement. BMS acknowledges that: (i) subject to Section 3.3 of this
Agreement, PROGENICS has certain rights to terminate the
Sloan-Kettering/PROGENICS License Agreement pursuant to Sections 9.01 and 9.04
thereof; and (ii) Sloan-Kettering and, subject to Section 3.3 of this Agreement,
PROGENICS have certain rights to terminate the Sloan-Kettering/PROGENICS License
Agreement upon the default, bankruptcy, insolvency or similar such event of the
other party, pursuant to Section 9.02 thereof.

      8.3 Breach by Either Party. Failure by either Party to comply with any of
the material obligations of such Party contained in this Agreement shall entitle
the other Party to give notice to the defaulting Party specifying the nature of
the default and requiring it to cure such default. If such default is not cured
within 60 days after the receipt of such notice (or, if such default cannot be
cured within such 60-day period, if the defaulting Party does not commence and
diligently continue actions to cure such default), the other Party shall be
entitled, without prejudice to any of its other rights conferred on it by this
Agreement, in addition to any other remedies available to it by law or in
equity, to terminate this Agreement by giving written notice to take effect
immediately. The right to terminate this Agreement, as hereinabove provided,
shall not be affected in any way by the other Party's waiver or failure to take
action with respect to any previous default.

      8.4  Effect of Termination.

            (a) Following termination of this Agreement pursuant to Section 8.1,
BMS shall have the right to manufacture, have manufactured, use, sell, have
sold, and develop S-K Products without further obligations to PROGENICS
hereunder.


                                      -20-
<PAGE>

            (b) Upon termination of this Agreement in its entirety for any
reason other than expiration of this Agreement pursuant to Section 8.1, BMS
shall promptly: (1) return to PROGENICS, at BMS's expense, all relevant data and
other information concerning the S-K Licensed Patents and S-K Technical
Information in the possession or control of BMS, its Affiliates and
Sub-sublicensees; (2) transfer, at BMS's expense, to PROGENICS or such other
Person, as PROGENICS shall designate, any and all rights that it may have under
any government registrations or authorizations in any country in the Territory
with respect to the S-K Products; (3) cancel, at BMS's expense, any government
registrations or authorizations with respect to the S-K Products as may not be
transferable; (4) provide to PROGENICS, at BMS's expense, all data and other
information in BMS's, or its Affiliates' or Sub-sublicensees', possession or
control relating to such governmental registrations or authorities in any
country in the Territory with respect to all S-K Products; and (5) discontinue
all manufacture, use, sale and distribution of all S-K Products and the use of
the S-K Licensed Patents and S-K Technical Information in connection therewith.
All rights granted to BMS under this Agreement shall revert to PROGENICS.

      8.5 Right to Sell Stock on Hand. If BMS is not in material breach of this
Agreement at the time of termination of this Agreement, then BMS shall have the
right for one year thereafter to dispose of all S-K Products then in its
inventory, and shall pay royalties thereon, in accordance with the provisions of
this Agreement, as though this Agreement had not terminated.

      8.6  Termination of Sublicenses. Upon any termination of this Agreement,
all sublicenses granted by BMS under this Agreement shall terminate
simultaneously, subject, nevertheless, to Section 8.5.

      8.7  Accrued Rights; Surviving Obligations.

            (a) Termination, relinquishment or expiration of this Agreement for
any reason shall be without prejudice to any rights which shall have accrued to
the benefit of either Party prior to such termination, relinquishment or
expiration. Such termination, relinquishment or expiration shall not relieve
either Party from obligations which are expressly indicated to survive
termination or expiration of this Agreement.

            (b) Termination of this Agreement shall not terminate BMS's
obligation to pay the royalties for S-K Products which has been sold under this
Agreement. All of the Parties' rights and obligations under Sections 1, 6,
7.3(b), (c) and (d), 7.4 (solely with respect to actions in existence at the
time of termination), 8.4, 8.5, 10.5, 10.6, 10.11, 10.15 and 10.16 shall survive
termination.



                                      -21-
<PAGE>

9.  ASSIGNABILITY.

      9.1 Non-Assignability. The Parties agree that this Agreement imposes
personal obligations on BMS. BMS shall not assign any rights under this
Agreement not specifically transferable by its terms (other than to an
Affiliate). PROGENICS may not assign its rights hereunder (other than to any
assignee of all or substantially all of its business, which assignee has
previously agreed to be bound by all of the terms and conditions of this
Agreement). Any purported assignment not in accordance with this Section 9.1
shall be ineffective.

      9.2 Assignability. BMS acknowledges that Sloan-Kettering may assign its
rights under the Sloan-Kettering/PROGENICS License Agreement, but not to a
competitor of PROGENICS.

10.  MISCELLANEOUS.

      10.1 Relationship of Parties. Nothing in this Agreement is intended or
shall be deemed to constitute a partnership, agency, employer-employee or joint
venture relationship between the Parties. No Party shall incur any debts or make
any commitments for the other, except to the extent, if at all, specifically
provided herein.

      10.2 Force Majeure. Neither Party shall be liable to the other for loss or
damages or shall have any right to terminate this Agreement for any default or
delay attributable to any act of God, flood, fire, explosion, strike, lockout,
labor dispute, shortage of raw materials, casualty or accident, war, revolution,
civil commotion, act of public enemies, blockage or embargo, injunction, law,
order, proclamation, regulation, ordinance, demand or requirement of any
government or subdivision, authority or representative of any such government,
or any other cause beyond the reasonable control of such Party, if the Party
affected shall give prompt notice of any such cause to the other Party. The
Party giving such notice shall thereupon be excused from such of its obligations
hereunder as it is thereby disabled from performing for so long as it is so
disabled and for 30 days thereafter. Notwithstanding the foregoing, nothing in
this Section 10.2 shall excuse or suspend the obligation to make any payment due
hereunder in the manner and at the time provided.

      10.3 Further Actions. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all such other acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

      10.4  Notice. Any notice or request required or permitted to be given
under or in connection with this Agreement shall be deemed to have been
sufficiently given if in writing and personally


                                      -22-
<PAGE>

delivered by messenger, facsimile transmission (receipt verified), express
courier service (signature required), or telegram, prepaid, to the Party for
which such notice is intended, at the address set forth for such Party below:

            (a)  In the case of PROGENICS, to:

                        Progenics Pharmaceuticals, Inc.
                        777 Old Saw Mill River Road
                        Tarrytown, New York 10591
                        Attention: Dr. Paul Maddon
                        Facsimile No.: (914) 789-2817

            (b)  In the case of BMS, to:

                        Bristol-Myers Squibb Company
                        P.O. Box 4000
                        Route 206 & Province Line Road
                        Princeton, New Jersey 08543-4000
                        Attention:  Vice President and Senior
                        Counsel, Pharmaceutical Research
                        Institute, and Worldwide Franchise
                        Management and Strategic Business
                        Development
                        Facsimile No.:  (609) 252-4232

            (c)  In the case of Sloan-Kettering, to:

                        Sloan-Kettering Institute for Cancer Research
                        1275 York Avenue
                        New York, New York 10021
                        Attention:  Senior Vice President, Research
                          Resources Management
                        Facsimile No.: (212) 753-5764

or to such other address for such Party as it shall have specified by like
notice to the other Party, provided that notices of a change of address shall be
effective only upon receipt thereof. If sent by messenger, facsimile
transmission, express courier service, or telegram, the date of mailing or
transmission shall be deemed to be the date on which such notice or request has
been given.

      10.5 Use of Name. Except as otherwise provided herein, neither Party shall
have any right, express or implied, to use in any manner the name or other
designation of, or otherwise refer to, the other Party (and, in the case of BMS,
Sloan-Kettering or any organization related to Sloan-Kettering), or any other
trade name or trademark of the other Party, for any purpose in connection with
the performance of this Agreement, without the written approval of the other
Party or Sloan-Kettering, as the case may be, except that BMS may make
statements to the effect that (i) it is sublicensed by PROGENICS, pursuant to
this Agreement and further pursuant to the


                                      -23-
<PAGE>

Sloan-Kettering/PROGENICS License Agreement, under the S-K Licensed Patents, and
(ii) Alan B. Houghton, M.D., Philip O. Livingston, M.D. and David A. Scheinberg,
M.D., Ph.D. are staff of Sloan-Kettering and there is a relationship between
these individuals and PROGENICS. It is understood that the other Party or
Sloan-Kettering, as the case may be, shall respond to any request for the use of
such name or the making of such reference within 14 days after the receipt of
such request.

      10.6  Non-Solicitation. BMS shall not hire as board members or employees
any of [xxx] without first obtaining Sloan-Kettering's prior written
consent.

      10.7 Marking. BMS, its Affiliates and its Sub-sublicensees shall place in
a conspicuous location on S-K Products that would infringe S-K Licensed Patents
but for this Agreement and the Sloan-Kettering/PROGENICS License Agreement, a
patent notice in accordance with 35 U.S.C. ss. 282. BMS agrees to mark, and to
cause its Affiliates and its Sub-sublicensees to mark, any products made using a
process covered by any S-K Licensed Patent with the number of each such patent
and, with respect to such S-K Licensed Patents, to respond to any request for
disclosure under 35 U.S.C. ss.287 (b)(4)(B) by only notifying PROGENICS of the
request for disclosure.

      10.8 Costs and Expenses. Except as otherwise expressly provided in this
Agreement, each Party shall bear all costs and expenses associated with the
performance of such Party's obligations under this Agreement.

      10.9  Manufacture in United States. S-K Product(s) used, sold, leased, or
transferred within the United States shall be manufactured substantially in the
United States.

      10.10 Waiver. A waiver by either Party of any of the terms and conditions
of this Agreement in any instance shall not be deemed or construed to be a
waiver of such term or condition for the future, or of any subsequent breach
hereof. All rights, remedies, undertakings, obligations and agreements contained
in this Agreement shall be cumulative and none of them shall be in limitation of
any other remedy, right, undertaking, obligation or agreement of either Party.

      10.11  Compliance with Law.

            (a) BMS agrees to comply with the laws and rules of the Government
regarding prohibition of exportation of S-K Technical Information furnished to
BMS either directly or indirectly by PROGENICS or Sloan-Kettering.



                                      -24-
<PAGE>

            (b) BMS, its Affiliates and its Sub-sublicensees shall comply upon
reasonable notice from PROGENICS or Sloan-Kettering with all governmental
requests directed to PROGENICS or Sloan-Kettering and provide all information
and assistance necessary to comply with the governmental requests.

      10.12 Severability. When possible, each provision of this Agreement will
be interpreted in such manner as to be effective and valid under applicable law,
but if any provision of this Agreement is held to be prohibited by or invalid
under applicable law, such provision will be ineffective only to the extent of
such prohibition or invalidity, without invalidating the remainder of this
Agreement.

      10.13 Amendment. No amendment, modification or supplement of any
provisions of this Agreement shall be valid or effective unless made in writing
and signed by a duly authorized officer of each Party.

      10.14  Sloan-Kettering/PROGENICS License Agreement.

            (a) This Agreement shall automatically be modified, in whole or in
part, upon any modification, in whole or in part, of the
Sloan-Kettering/PROGENICS License Agreement, if and to the extent that such
modification is relevant and affects the terms of this Agreement. Such
modification of this Agreement shall be consistent with and reflect the
modification of the Sloan-Kettering/PROGENICS License Agreement.

            (b) The Parties acknowledge and agree that Sections 1, 3.1, 6.3,
7.3(a), 7.3(c), 7.3(d), 8.1, 8.2, 8.7, 9, 10.5, 10.6, 10.7, 10.11(a) and 10.15
of this Agreement have been included herein in satisfaction of Section 6.02 of
the Sloan-Kettering License Agreement. BMS acknowledges and agrees that
Sloan-Kettering shall be a third party beneficiary under this Agreement with
respect to the foregoing sections.

      10.15  Governing Law. This Agreement shall be governed by and interpreted
in accordance with the laws of the State of New York without regard to its
choice of law principles.

      10.16 Arbitration. Any dispute arising out of or relating to any
provisions of this Agreement shall be finally settled by arbitration to be held
in New York, New York, under the auspices and then current commercial
arbitration rules of the American Arbitration Association. Such arbitration
shall be conducted by three (3) arbitrators appointed according to said rules.
Judgment upon any award rendered may be entered in any court having
jurisdiction, or application may be made to such court for a judicial acceptance
of the award and an order of enforcement, as the case may be.


                                      -25-
<PAGE>

      10.17 Counterparts. This Agreement may be executed simultaneously in any
number of counterparts, any one of which need not contain the signature of more
than one Party but all such counterparts taken together shall constitute one and
the same agreement.

      10.18  Descriptive Headings. The descriptive headings of this Agreement
are for convenience only, and shall be of no force or effect in construing or
interpreting any of the provisions of this Agreement.

      IN WITNESS WHEREOF, each of the Parties has caused this Agreement to be
executed and delivered by its duly authorized officer as of the day and year
first above written.


                                      PROGENICS PHARMACEUTICALS, INC.


                                      By: /s/ Paul J. Maddon
                                          --------------------------------
                                      Name:  Paul J. Maddon, M.D., Ph.D.
                                      Title:  Chairman and Chief 
                                                Executive Officer


                                      BRISTOL-MYERS SQUIBB COMPANY


                                      By: /s/ Charles Linzner
                                          --------------------------------

                                      Name: Charles Linzner
                                            ------------------------------

                                      Title: Vice President
                                             -----------------------------


                                      -26-
<PAGE>

                                    EXHIBIT A

                              S-K LICENSED PATENTS

    Application or Patent Number             Filing or Issue Date
    ----------------------------             --------------------

              [XXX]                                 [XXX]



<PAGE>

                                                                   Exhibit 10.25


                              SUBLICENSE AGREEMENT
                 WITH RESPECT TO THE REGENTS' LICENSE AGREEMENT

                                     BETWEEN

                         PROGENICS PHARMACEUTICALS, INC.

                                       AND

                          BRISTOL-MYERS SQUIBB COMPANY

                                   DATED AS OF

                                 APRIL 15, 1997


[Note: Certain portions of this document have been marked "[XXX]" to 
indicate that confidentiality has been requested for this information. The 
confidential portions have been omitted and filed separately with the 
Securities and Exchange Commission.]

<PAGE>

                                TABLE OF CONTENTS

                                                                            Page
                                                                            ----
1.    DEFINITIONS ..........................................................  1
      1.1      "Affiliate" .................................................  1
      1.2      "BCG" .......................................................  2
      1.3      "Effective Date" ............................................  2
      1.4      "FDA" .......................................................  2
      1.5      "First Commercial Sale" .....................................  2
      1.6      "GD2" .......................................................  2
      1.7      "GM2" .......................................................  2
      1.8      "GMK Vaccine" ...............................................  2
      1.9      "Invention" .................................................  2
      1.10     "KLH" .......................................................  2
      1.11     "MGV Vaccine" ...............................................  2
      1.12     "Net Sales" .................................................  2
      1.13     "Party" .....................................................  3
      1.14     "Person" ....................................................  3
      1.15     "PLA" .......................................................  3
      1.16     "QS-21" .....................................................  3
      1.17     "Regents' Field" ............................................  3
      1.18     "Regents' Method" ...........................................  3
      1.19     "Regents' Patent Rights" ....................................  3
      1.20     "Regents' Product" ..........................................  3
      1.21     "Sub-sublicensee" ...........................................  4
      1.22     "Territory" .................................................  4
      1.23     "Third Party" ...............................................  4
             
2.    REPRESENTATIONS AND WARRANTIES OF PROGENICS ..........................  4
      2.1      Representations and Warranties ..............................  4

3.    GRANT OF RIGHTS ......................................................  4
      3.1      Sublicense Grant Under The Regents/PROGENICS License
               Agreement ...................................................  4
      3.2      Sublicense Rights ...........................................  5
      3.3      BMS Rights under The Regents/PROGENICS License
               Agreement ...................................................  6

4.    UPFRONT FEE; MILESTONE AND ROYALTY PAYMENTS ..........................  7
      4.1      Upfront Fee .................................................  7
      4.2      Milestone Payments Regarding GMK Vaccine ....................  7
      4.3      Milestone Payments Regarding MGV Vaccine ....................  8
      4.4      Royalty Payments ............................................  9
      4.5      Obligation to Pay Royalties .................................  9

5.    DILIGENCE OBLIGATIONS OF BMS ......................................... 10
      5.1      Commercialization ........................................... 10
      5.2      Governmental Approvals ...................................... 10
      5.3      Diligence Obligations ....................................... 10


                                       (i)
<PAGE>

                          TABLE OF CONTENTS (continued)
                                                                            Page
                                                                            ----

6.    PAYMENTS AND REPORTS ................................................. 11
      6.1      Reports; Payments ........................................... 11
      6.2      Mode of Payment; Taxes ...................................... 11
      6.3      Records Retention ........................................... 11
      6.4      Audit Request ............................................... 11
      6.5      Cost of Audit ............................................... 12
      6.6      No Non-Monetary Consideration for Sales ..................... 12
      6.7      Small Entity Status ......................................... 12

7.    PATENT FILING, PROSECUTION AND MAINTENANCE ........................... 12
      7.1      Patent Prosecution .......................................... 12
      7.2      Patent Costs ................................................ 13

8.    PATENT ENFORCEMENT AND INFRINGEMENT .................................. 13
      8.1      Patent Enforcement .......................................... 13

9.    TERM; TERMINATION .................................................... 14
      9.1      Term ........................................................ 14
      9.2      Breach by Either Party ...................................... 14
      9.3      Effect of Termination ....................................... 14
      9.4      Right to Sell Stock on Hand ................................. 15
      9.5      Termination of Sublicenses .................................. 15
      9.6      Accrued Rights; Surviving Obligations ....................... 15

10.   NON-ASSIGNABILITY .................................................... 16
      10.1     Non-Assignability ........................................... 16

11.   MISCELLANEOUS ........................................................ 16
      11.1     Relationship of Parties ..................................... 16
      11.2     Force Majeure ............................................... 16
      11.3     Further Actions ............................................. 16
      11.4     Notice ...................................................... 16
      11.5     Use of Name ................................................. 17
      11.6     Marking ..................................................... 17
      11.7     Costs and Expenses .......................................... 18
      11.8     Manufacture in United States ................................ 18
      11.9     Waiver ...................................................... 18
      11.10    Compliance with Law ......................................... 18
      11.11    Severability ................................................ 18
      11.12    Amendment ................................................... 18
      11.13    Governing Law ............................................... 19
      11.14    Arbitration ................................................. 19
      11.15    Counterparts ................................................ 19
      11.16    Descriptive Headings ........................................ 19


                                      (ii)
<PAGE>

                              SUBLICENSE AGREEMENT
                WITH RESPECT TO THE REGENTS' LICENSE AGREEMENT

      THIS SUBLICENSE AGREEMENT WITH RESPECT TO THE REGENTS' LICENSE AGREEMENT
(this "Agreement") is dated as of April 15, 1997 between Progenics
Pharmaceuticals, Inc., a Delaware corporation, having offices at 777 Old Saw
Mill River Road, Tarrytown, New York 10591 ("PROGENICS"), and Bristol-Myers
Squibb Company, a Delaware corporation, having offices at P.O. Box 4000, Route
206 and Province Line Road, Princeton, New Jersey 08543-4000, for and on behalf
of itself and its Affiliates ("BMS").

                             PRELIMINARY STATEMENTS

      A. PROGENICS has entered into a license agreement dated June 25, 1996
("The Regents/PROGENICS License Agreement") with The Regents of The University
of California, a California corporation ("The Regents") pursuant to which
PROGENICS acquired a license to certain patent rights relating to vaccines
relating to the treatment of human cancers.

      B. BMS is interested in obtaining a worldwide sublicense to formulate,
manufacture, use and sell products using the patent rights and technology to
which PROGENICS has acquired a license from The Regents, and PROGENICS wishes to
grant such rights to BMS, pursuant to the terms and conditions set forth in this
Agreement.

      C. It is anticipated that BMS, PROGENICS and The Regents will enter into a
side letter agreement (the "Regents Letter Agreement") with respect to this
Agreement and The Regents/PROGENICS License Agreement, and the rights and
obligations of such parties hereunder and thereunder.

      NOW, THEREFORE, in consideration of the mutual covenants and agreements of
the Parties contained in this Agreement, the Parties agree as follows:

1. DEFINITIONS.

      As used in this Agreement, the following terms will have those meanings
set forth in this Section 1 unless the context dictates otherwise.

      1.1 "Affiliate", with respect to any Party, shall mean any Person which,
directly or indirectly, controls, is controlled by, or is under common control
with, such Party. For these purposes, "control" shall refer to the possession,
directly or indirectly, of the power to direct the management or policies of a
Person or to veto any material decision relating to the management or policies
of a Person, in each case, whether through the ownership of equity
participation, voting securities or beneficial interests, by contract, by
agreement, or otherwise.
<PAGE>

      1.2 "BCG" shall mean bacille Calmette et Guerin, a nonspecific immune
stimulant (cow tuberculosis) vaccine.

      1.3 "Effective Date" shall mean the date first above written as the date
of this Agreement.

      1.4 "FDA" shall mean the United States Food and Drug Administration, or
the successor thereto.

      1.5 "First Commercial Sale" shall mean, in each country in the Territory,
the date that the Regents' Product(s) are first sold, marketed or publicly made
available for sale. Regents' Product(s) distributed or used for clinical trials
or experimental purposes only shall not be considered sold, marketed or made
publicly available and shall not establish the First Commercial Sale.

      1.6 "GD2" shall mean [XXX].

      1.7 "GM2" shall mean [XXX].

      1.8 "GMK Vaccine" shall mean that certain Regents' Product composed of GM2
conjugated to KLH and combined with QS-21.

      1.9 "Invention" shall mean that certain invention generally characterized
as "Antigenic Compositions and Methods for Using Same" (U.S. Case No. 92-078-01)
that was made in the course of research at the University of California, Los
Angeles, by Reiko Irie, Tadashi Tai, Donald L. Morton, James C. Paulson and
Leslie Cahan.

      1.10 "KLH" shall mean keyhole limpet hemocyanin.

      1.11 "MGV Vaccine" shall mean that certain Regents' Product composed of
GM2 conjugated to KLH and combined with GD2 conjugated to KLH and further
combined with QS-21.

      1.12 "Net Sales" shall mean the gross amount invoiced by BMS [XXX]


                                       -2-
<PAGE>

[XXX]. Such amounts shall be determined from the books and records of BMS, its
Affiliates or Sub-sublicensees, maintained in accordance with the accounting
principles used by such entity, consistently applied.

      1.13 "Party" shall mean PROGENICS or BMS and, when used in the plural,
shall mean PROGENICS and BMS.

      1.14 "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, or any organization which can exercise independent legal standing.

      1.15 "PLA" shall mean a Product License Application filed with the FDA.

      1.16 "QS-21" shall mean the [XXX].

      1.17 "Regents' Field" shall mean, and is limited to, the practice of the
Regents' Patent Rights for the prevention or treatment of neoplastic human
disease or the prevention or treatment of human cancer with any of the
following: (i) GM2-KLH conjugated vaccines plus QS-21, or (ii) GD2-KLH
conjugated vaccines plus QS-21, or (iii) GM2 attached to the surface of BCG, or
(iv) any combination of the above.

      1.18 "Regents' Method" shall mean any process or method which is covered
by the Regents' Patent Rights or the use or practice of which would constitute
an infringement of any claim within the Regents' Patent Rights.

      1.19 "Regents' Patent Rights" shall mean patent rights to any subject
matter claimed in or covered by the patent entitled "Antigenic Compositions and
Methods for Using Same," U.S. patent No. 4,557,931 (issued December 10, 1985),
assigned to The Regents (UCLA Case No. LA92-078-01), including reissues and
reexaminations. The Regents' Patent Rights shall include, without limitation,
the Invention.

      1.20 "Regents' Product" shall mean any article, composition, apparatus,
substance, chemical, or any other material covered by the Regents' Patent Rights
or the manufacture, use or sale of which would constitute an infringement of any
claim within the Regents' Patent Rights, or any service, article, composition,
apparatus, chemical, substance, or any other material made, used, or sold
utilizing or practicing a Regents' Method in the Regents' Field.


                                       -3-
<PAGE>

      1.21 "Sub-sublicensee" shall mean any Third Party sublicensed by BMS to
make, have made, use, sell, or have sold any Regents' Product or to practice any
Regents' Method.

      1.22 "Territory" shall mean all jurisdictions where the Regents' Patent
Rights exist, from time to time.

      1.23 "Third Party" shall mean any Person who or which is neither a Party
nor an Affiliate of a Party.

2. REPRESENTATIONS AND WARRANTIES OF PROGENICS.

      2.1 Representations and Warranties. PROGENICS represents and warrants to
BMS as of the Effective Date as follows:

            (a) The Regents/PROGENICS License Agreement is in full force and
effect and has not been modified or amended;

            (b) To the best of PROGENICS's knowledge, neither The Regents nor
PROGENICS is in default under, and neither party claims or has grounds upon
which to claim the other party is in default under, The Regents/PROGENICS
License Agreement;

            (c) To the best of PROGENICS's knowledge, the rights The Regents has
licensed to PROGENICS pursuant to The Regents/PROGENICS License Agreement were
not and are not subject to any restrictions or limitations except as set forth
in The Regents/PROGENICS License Agreement;

            (d) To the best of PROGENICS's knowledge, the Regents has not
accepted funding from any non-governmental parties which would diminish
PROGENICS's rights to technology under The Regents/PROGENICS License Agreement;
and

            (e) The milestones set forth in Sections 6.3(a) and 6.3(d) of The
Regents/PROGENICS License Agreement have been fully satisfied by PROGENICS as of
the Effective Date.

3. GRANT OF RIGHTS.

      3.1 Sublicense Grant Under The Regents/PROGENICS License Agreement.

            (a) Subject to the terms and conditions of this Agreement and the
rights of The Regents under The Regents/PROGENICS License Agreement, PROGENICS
hereby grants BMS an exclusive (even as to PROGENICS) sublicense, under The
Regents License Agreement, to use the Regents' Patent Rights in the Territory,
to make, have made, use, sell, have sold and offer to sell Regents' Products and
to practice the Regents' Method in the Regents' Field.


                                       -4-
<PAGE>

            (b) The sublicense granted in this Section 3.1 shall be granted to
Affiliates of BMS five days after receipt of written notification by PROGENICS.

            (c) The sublicense granted in Section 3.1(a) is subject to all the
applicable provisions of any license to the United States Government executed by
The Regents. The sublicense granted in Section 3.1(a) is subject to any
overriding obligations to the United States Federal Government under 35 U.S.C.
ss.ss.201-212.

            (d) BMS hereby acknowledges that the Regents have expressly reserved
the right to use the Regents' Patent Rights and associated technology for
educational, research and clinical purposes and for any other purpose that is
not inconsistent with the rights granted to PROGENICS in The Regents/PROGENICS
License Agreement.

      3.2 Sublicense Rights.

            (a) BMS shall have the right to grant sublicenses to its Affiliates
of the sublicense granted to BMS herein, provided that: (i) BMS shall guarantee
and be responsible for the making of all payments due, and the making of reports
under this Agreement, by reason of sales of any Regents' Products by its
Affiliates and their compliance with all applicable terms of this Agreement
(including the applicable terms of The Regents/PROGENICS License Agreement); and
(ii) each Affiliate agrees in writing to keep books and records and permit
PROGENICS to review such books and records pursuant to the relevant provisions
and to observe all other applicable terms of this Agreement. No consent or
approval of PROGENICS shall be required in connection with the granting of such
sublicenses.

            (b) BMS shall have the right to grant sublicenses to
Sub-sublicensees of the sublicense granted to BMS herein, except that BMS does
not have the right to grant such sublicenses with respect to the United States,
provided that: (i) PROGENICS shall have consented to such sublicense, which
approval shall not be unreasonably withheld (it will be reasonable for PROGENICS
to withhold consent if PROGENICS determines that the capabilities of the
proposed Sub-sublicensee are not comparable to BMS's capabilities in the country
or countries to be sublicensed); (ii) BMS shall guarantee and be responsible for
the making of all payments due, and the making of reports under this Agreement,
by reason of sales of any Regents' Products by its Sub-sublicensees and their
compliance with all applicable terms of this Agreement (including the applicable
terms of The Regents/PROGENICS License Agreement); and (iii) each
Sub-sublicensee agrees in writing to keep books and records and permit PROGENICS
to review such books and records pursuant to the relevant provisions and to
observe all other applicable terms of this Agreement.


                                       -5-
<PAGE>

            (c) BMS hereby unconditionally guarantees the performance of any of
its Affiliates and Sub-sublicensees hereunder. In the event of a breach by an
Affiliate or Sub-sublicensee in the observance of applicable terms of this
Agreement, PROGENICS shall be entitled to proceed against either such Affiliate
or Sub-sublicensee or directly against BMS, as PROGENICS may determine in its
sole discretion, to enforce this Agreement.

      3.3 BMS Rights under The Regents/PROGENICS License Agreement. PROGENICS
agrees that, with respect to The Regents/PROGENICS License Agreement:

            (a) PROGENICS will diligently fulfill all of its obligations
thereunder, to the extent such obligations have not been delegated to BMS;

            (b) PROGENICS shall not enter into any subsequent agreement with The
Regents which modifies or amends The Regents/ PROGENICS License Agreement in a
way which is deleterious to the rights of BMS under this Agreement;

            (c) PROGENICS shall not terminate The Regents/PROGENICS License
Agreement, in whole or in part, directly or indirectly, without the prior
written consent of BMS, which shall not be unreasonably withheld in the event
that The Regents is in material default under the terms thereof at the time
PROGENICS seeks to make such exercise;

            (d) PROGENICS shall promptly furnish BMS with copies of all reports
it receives from The Regents which relate to the subject of this Agreement;

            (e) PROGENICS shall promptly furnish BMS with copies of all reports
PROGENICS furnishes to The Regents which relate to the subject of this
Agreement, including without limitation all correspondence of any kind with
respect to the filing, prosecution or maintenance of the Regents' Patent Rights
in any jurisdiction;

            (f) PROGENICS shall promptly deliver to The Regents' patent counsel
all of BMS's comments and decisions with respect to the filing, prosecution or
maintenance of the patents comprising the Regents' Patent Rights in any
jurisdiction, including without limitation requests for filing for foreign
protection and notices of elections pursuant to Section 7.4 of The
Regents/PROGENICS License Agreement, as if such comments were comments of
PROGENICS; and

            (g) PROGENICS shall furnish to BMS copies of all notices received by
PROGENICS relating to alleged breaches or defaults by PROGENICS of its
obligations under The Regents/PROGENICS License Agreement within three business
days of


                                       -6-
<PAGE>

PROGENICS's receipt thereof and, provided that if PROGENICS cannot or chooses
not to cure or otherwise resolve such alleged breaches or defaults, PROGENICS
shall allow BMS, in BMS's sole discretion, to cure or otherwise resolve such
alleged breaches or defaults in order to preserve BMS's rights under this
Agreement.

4. UPFRONT FEE; MILESTONE AND ROYALTY PAYMENTS.

      4.1 Upfront Fee. As consideration to PROGENICS for the grant of the
sublicense and other rights to BMS under this Agreement, BMS shall pay to
PROGENICS the sum of $150,000. Such up-front fee shall be paid upon the
execution of this Agreement by both Parties. Such sum shall be non-refundable.

      4.2 Milestone Payments Regarding GMK Vaccine. As consideration to
PROGENICS for the sublicense and other rights granted to BMS by PROGENICS under
this Agreement, and subject to prior termination of this Agreement in whole or
in all countries in the Territory with respect the Regents' Product to which any
milestone payment relates, BMS shall pay to PROGENICS the following milestone
payments upon the occurrence of each event set forth below:

            (a) [XXX];

            (b) [XXX];

            (c) [XXX];

            (d) [XXX];

            (e) [XXX]; and


                                       -7-
<PAGE>

            (f) [XXX].

            Each of the payments required pursuant to this Section 4.2 shall be
paid within 30 days after such milestone has been achieved, and shall be
non-refundable.

      4.3 Milestone Payments Regarding MGV Vaccine. As consideration to
PROGENICS for the sublicense and other rights granted to BMS by PROGENICS under
this Agreement, and subject to prior termination of this Agreement in whole or
in all countries in the Territory with respect the Regents' Product to which any
milestone payment relates, BMS shall pay to PROGENICS the following milestone
payments upon the occurrence of each event set forth below:

            (a) [XXX].

            (b) [XXX];

            (c) [XXX];

            (d) [XXX];

            (e) [XXX];

            (f) [XXX]; and


                                       -8-
<PAGE>

            (g) [XXX].

            With respect to the milestones set forth in Sections 4.3(b) through
(g) above, the Parties may mutually agree to cause any of such milestones to
apply to another cancer type with comparable projected market potential as the
cancer type set forth in such milestone.

            Each of the payments required pursuant to this Section 4.3 shall be
paid within 30 days after such milestone has been achieved and shall be
non-refundable.

      4.4 Royalty Payments. As consideration to PROGENICS for the sublicense and
other rights granted to BMS under this Agreement, during the term of this
Agreement, BMS shall pay to PROGENICS a royalty on Net Sales of any Regents'
Product commencing on the First Commercial Sale of such Regents' Product by BMS,
its Affiliates or its Sub-sublicensees as follows:

            (a) With respect to the GMK Vaccine and with respect to each country
in the Territory:

                  (i) [XXX] of the Net Sales of such Regents' Product in such
            country for any calendar year until Net Sales throughout the
            Territory in such calendar year equal [XXX]; and

                  (ii) After Net Sales for such Regents' Product throughout the
            Territory in such calendar year exceed [XXX] of any further Net
            Sales of such Regents' Product in such country until the end of such
            calendar year.

            (b) With respect to the MGV Vaccine and any other Regents' Products,
and with respect to each country in the Territory, [XXX] of the Net Sales of 
such Regents' Product in such country for any calendar year.

      4.5 Obligation to Pay Royalties. The obligation to pay royalties to
PROGENICS under Section 4.4 is imposed only once with respect to the same unit
of Regents' Product regardless of the number of Regents' Patents Rights
pertaining thereto. BMS shall only be entitled to a credit against royalties or
a reduction of the royalty rate once with respect to any Regents' Product in any
country pursuant to any provision in this Agreement. There shall be no
obligation to pay royalties to PROGENICS under Section 4.4 on


                                       -9-
<PAGE>

sales of Regents' Products among BMS, its Affiliates and Sub-sublicensees, but
in such instances the obligation to pay royalties shall arise upon the sale by
BMS, its Affiliates or Sub-sublicensees to Third Parties. Payments due under
Section 4.4 shall be deemed to accrue when Regents' Products are shipped or
billed, whichever event shall first occur. In the instance where BMS, its
Affiliates or Sub-sublicensees use the Regents' Product or provide it as part of
some other service or product, a royalty shall be due to PROGENICS at the time
such Regents' Product is used or provided based on a Net Sales amount equal to
the price at which BMS or its Affiliate or Sub-sublicensee sell such Regents'
Product to Third Parties in the country in which the Regents' Product was used
or provided.

5. DILIGENCE OBLIGATIONS OF BMS.

      5.1 Commercialization. Subject to the terms of this Agreement, BMS, its
Affiliates or its Sub-sublicensees must diligently proceed with the development,
manufacture and sale ("Commercialization") of Regents' Products and must
earnestly and diligently endeavor to market them within a reasonable time after
execution of this Agreement and in quantities sufficient to meet the market
demands therefor.

      5.2 Governmental Approvals. Subject to the terms of this Agreement, BMS,
its Affiliates or Sub-sublicensees must endeavor to obtain all necessary
governmental approvals for the Commercialization of the Regents' Products.

      5.3 Diligence Obligations. Pursuant to this Agreement, BMS, its Affiliates
or its Sub-sublicensees shall achieve the following objectives in accordance
with the following schedule:

            (i)   [XXX]; and

            (ii)  [XXX].

      The parties acknowledge and agree that the milestones contained in this
Section 5.3 were established on the assumption that the milestones would apply
to development of the GMK Vaccine. In the event that the development of the GMK
Vaccine is terminated due to safety or efficacy reasons, the Parties agree that
the milestones set forth in this Section 5.3 shall not apply and the Parties
will negotiate in good faith to establish new milestones.


                                      -10-
<PAGE>

6. PAYMENTS AND REPORTS.

      6.1 Reports; Payments. Except as otherwise specifically provided in this
Agreement, all payments due under this Agreement shall be paid quarterly within
50 days after the end of each calendar quarter. Each such payment for running
royalties shall be accompanied by a statement, Regents' Product-by-Regents'
Product and country-by-country, of the amount of Net Sales during such quarter
and the amount of royalties due on such Net Sales.

      6.2 Mode of Payment; Taxes. All payments due under this Agreement shall be
paid by wire transfer of funds to an account at PROGENICS's designated bank in
New York, New York, and shall be paid in U.S. Dollars, calculated at BMS's
customary internal corporate monthly exchange rates for the last month of the
calendar quarter for which remittance is made for royalties. Such payments shall
be free of any taxes, charges, or remittance fees, except for income tax levied
upon or required to be withheld and paid by BMS, its Affiliates or its
Sub-sublicensees for the account of PROGENICS. BMS shall provide PROGENICS
appropriate receipts of payment of such withholding taxes or other proof
thereof. For each month and each currency, BMS's customary internal corporate
monthly exchange rate shall equal the arithmetic average of the daily exchange
rates (obtained as described below) during the period from (i) the 20th day of
the preceding month (or, if such 20th day is not a business day, the immediately
preceding business day) through (ii) the 19th day of the current month (or, if
such 19th day is not a business day, the immediately preceding business day);
each daily exchange rate shall be obtained from the Reuters Daily Rate Report or
The Wall Street Journal, Eastern U.S. edition, or, if not so available, as
furnished by BMS's local Affiliates.

      6.3 Records Retention. BMS and its Affiliates and Sub-sublicensees shall
keep accurate records of all operations affecting payments hereunder, and shall
permit PROGENICS or its duly authorized agent to inspect all such records and to
make copies of or extracts from such records during regular business hours
throughout the term of this Agreement and for a reasonable period of not less
than three years thereafter.

      6.4 Audit Request. At the request and expense of PROGENICS, BMS and its
Affiliates and Sub-sublicensees shall permit PROGENICS or an independent,
certified public accountant appointed by PROGENICS and reasonably acceptable to
BMS, at reasonable times and upon reasonable notice, to examine those records as
may be necessary to: (i) determine the correctness of any report or payment made
under this Agreement; or (ii) obtain all information as to Net Sales and the
royalties payable for any calendar quarter. If an accountant is used, said
accountant shall not disclose to PROGENICS any information other than
information relating to said reports, royalties, and payments. Results of any
such examination shall be made available to both Parties.


                                      -11-
<PAGE>

      6.5 Cost of Audit. PROGENICS shall bear the full cost of the performance
of any such audit except as hereinafter set forth. If, as a result of any
inspection of the books and records of BMS, its Affiliates or its
Sub-sublicensees, it is shown that BMS's payments under this Agreement were less
than the amount which should have been paid, then BMS shall make all payments
required to be made to eliminate any discrepancy revealed by said inspection
within 30 days after PROGENICS's demand therefor, plus interest at the prime
rate from the date payment should have been made. Furthermore, if the payments
were less than the amount which should have been paid by an amount in excess of
five percent of the payments actually made during the period in question, BMS
shall also reimburse PROGENICS for the costs of such audit in addition to the
payment required to be made to eliminate any discrepancy.

      6.6 No Non-Monetary Consideration for Sales. Without the prior written
consent of PROGENICS, BMS and its Affiliates and Sub-sublicensees shall not
accept or solicit any non-monetary consideration in the sale of Regents'
Products other than as would be reflected in Net Sales. The use by BMS and its
Affiliates and Sub-sublicensees of commercially reasonable amounts of Regents'
Products for clinical trials and promotional sampling shall not violate this
provision.

      6.7 Small Entity Status. BMS must notify PROGENICS if BMS or any of its
Affiliates or Sub-sublicensees ceases to be a small entity (as defined by the
United States Patent and Trademark Office) under the provisions of 35 U.S.C.
ss.41(h). Pursuant to the preceding sentence, BMS hereby notifies PROGENICS that
BMS is not a small entity thereunder.

7. PATENT FILING, PROSECUTION AND MAINTENANCE.

      7.1 Patent Prosecution. BMS acknowledges and agrees that the Regents'
Patent Rights will continue to be prosecuted (in the case of patent
applications) and maintained (in the case of patents) by The Regents or
PROGENICS. PROGENICS agrees that the Regents' Patent Rights shall be prosecuted
and/or maintained in accordance with The Regents/PROGENICS License Agreement
with diligence the same as or greater than is used for PROGENICS's own patents
and patent applications. To the extent that PROGENICS has the right to do so,
PROGENICS shall not permit any Regents' Patent Right to be abandoned. PROGENICS
shall provide to BMS copies of each patent request for terminal disclaimer, and
request for reissue or reexamination of any patent under Regents' Patent Rights,
that PROGENICS receives from The Regents pursuant to The Regents/PROGENICS
License Agreement. PROGENICS shall submit any comments or suggestions made by
BMS with respect thereto to The Regents for consideration, to the extent
permitted under The Regents/PROGENICS License Agreement.


                                      -12-
<PAGE>

      7.2 Patent Costs. BMS shall, from time to time, upon invoice from
PROGENICS, promptly reimburse PROGENICS for all out-of-pocket costs and expenses
incurred in connection with the prosecution and maintenance of The Regents'
Patent Rights including amounts payable by PROGENICS to The Regents therefor as
required by The Regents/PROGENICS License Agreement.

8. PATENT ENFORCEMENT AND INFRINGEMENT.

      8.1 Patent Enforcement.

            (a) Each Party shall inform the other Party promptly in writing of
any alleged infringement of any Regents' Patent Rights by any Third Party of
which it shall have knowledge, and provide any available evidence of
infringement.

            (b) BMS acknowledges and agrees that The Regents shall have the
right to defend the Regents' Patent Rights against infringement or interference
by other parties. BMS further acknowledges and agrees that PROGENICS shall have
the right to join, and shall cooperate with The Regents in, any infringement
action brought by The Regents (however, as between PROGENICS and BMS, BMS shall
have the right, but not the obligation, to join any such action, at its own
expense, with respect to any infringement of the Regents' Patent Rights in the
Regents' Field).

            (c) BMS acknowledges and agrees that, under The Regents/PROGENICS
License Agreement, if The Regents elects not to commence suit for infringement
of the Regents' Patent Rights within 100 days after PROGENICS's request therefor
and if the infringement occurred during the period and in a jurisdiction where
the Third Party had allegedly infringed PROGENICS's exclusive rights under The
Regents/PROGENICS License Agreement, then PROGENICS may thereafter bring suit in
its own name (however, as between PROGENICS and BMS, BMS shall have the right,
but not the obligation, to prosecute at its own expense any infringement of the
Regents' Patent Rights in the Regents' Field). BMS further acknowledges and
agrees that The Regents shall have the right to join, and shall cooperate with
PROGENICS in, any infringement action brought by PROGENICS, at The Regents' sole
expense.

            (d) BMS acknowledges and agrees that [XXX] shall be entitled to any
recovery in a legal action brought by [XXX] to enforce any Regents Patent
Rights, pursuant to The Regents/PROGENICS License Agreement.

            (e) BMS acknowledges and agrees that any recovery in a legal action
brought jointly by The Regents and PROGENICS and fully participated in by both
shall [XXX]. (As between BMS and PROGENICS, from the portion allocated to
PROGENICS, each of


                                      -13-
<PAGE>

BMS and PROGENICS shall be entitled to reimbursement, pro rata, of expenses
incurred by such Party in connection with such action, and the balance remaining
from such allocation shall be divided as follows: [XXX] to BMS and the remaining
[XXX] to PROGENICS.)

            (f) BMS acknowledges and agrees that, in the event that PROGENICS
shall undertake the enforcement of any Regents' Patent Rights by litigation, any
recovery of damages by PROGENICS will be applied first toward PROGENICS's
unreimbursed expenses and fees relating to such suit. PROGENICS shall pay The
Regents a royalty of [XXX] of the remaining balance and shall be entitled to
retain the remainder. (As between BMS and PROGENICS, from such remainder, BMS
shall be entitled to reimbursement of expenses incurred by BMS in connection
with such action, and the balance remaining from such allocation shall be
divided as follows: [XXX] to BMS and the remaining [XXX] to PROGENICS.)

9. TERM; TERMINATION.

      9.1 Term. This Agreement shall commence as of the Effective Date of this
Agreement and, unless sooner terminated as provided hereunder, shall terminate
upon the expiration of the last to expire of the patents comprising the Regents'
Patent Rights, unless The Regents/PROGENICS License Agreement is sooner
terminated, pursuant to the terms thereof.

      9.2 Breach by Either Party. Failure by either Party to comply with any of
the material obligations of such Party contained in this Agreement shall entitle
the other Party to give notice to the defaulting Party specifying the nature of
the default and requiring it to cure such default. If such default is not cured
within 60 days after the receipt of such notice (or, if such default cannot be
cured within such 60-day period, if the defaulting Party does not commence and
diligently continue actions to cure such default), the other Party shall be
entitled, without prejudice to any of its other rights conferred on it by this
Agreement, in addition to any other remedies available to it by law or in
equity, to terminate this Agreement by giving written notice to take effect
immediately. The right to terminate this Agreement, as hereinabove provided,
shall not be affected in any way by the other Party's waiver or failure to take
action with respect to any previous default.

      9.3 Effect of Termination.

            (a) Upon termination of this Agreement pursuant to Section 9.1, BMS
shall have the right to make, have made, use, sell, have sold and offer to sell
Regents' Products and to practice Regents' Methods in the Regents' Field.


                                      -14-
<PAGE>

            (b) Upon termination of this Agreement in its entirety for any
reason other than expiration of this Agreement pursuant to Section 9.1, BMS
shall promptly: (1) return to PROGENICS, at BMS's expense, all relevant data and
other information concerning the Regents' Patent Rights in the possession or
control of BMS, its Affiliates and Sub-sublicensees; (2) transfer, at BMS's
expense, to PROGENICS or such other Person, as PROGENICS shall designate, any
and all rights that it may have under any government registrations or
authorizations in any country in the Territory with respect to the Regents'
Products; (3) cancel, at BMS's expense, any government registrations or
authorizations with respect to the Regents' Products as may not be transferable;
(4) provide to PROGENICS, at BMS's expense, all data and other information in
BMS's, or its Affiliates' or Sub-sublicensees', possession or control relating
to such governmental registrations or authorities in any country in the
Territory with respect to all Regents' Products; and (5) discontinue all
manufacture, use, sale and distribution of all Regents' Products and the use of
the Regents' Patent Rights in connection therewith. All rights granted to BMS
under this Agreement shall revert to PROGENICS.

      9.4 Right to Sell Stock on Hand. If BMS is not in material breach of this
Agreement at the time of termination of this Agreement, then BMS shall have the
right for one year thereafter to dispose of all Regents' Products then in its
inventory, and shall pay royalties thereon, in accordance with the provisions of
this Agreement, as though this Agreement had not terminated.

      9.5 Termination of Sublicenses. Upon any termination of this Agreement,
all sublicenses granted by BMS under this Agreement shall terminate
simultaneously, subject, nevertheless, to Section 9.4.

      9.6 Accrued Rights; Surviving Obligations.

            (a) Termination, relinquishment or expiration of this Agreement for
any reason shall be without prejudice to any rights which shall have accrued to
the benefit of either Party prior to such termination, relinquishment or
expiration. Such termination, relinquishment or expiration shall not relieve
either Party from obligations which are expressly indicated to survive
termination or expiration of this Agreement.

            (b) All of the Parties' rights and obligations under Sections 1, 6,
8.1 (solely with respect to actions in existence at the time of termination),
9.3, 9.4, 11.5, 11.6, 11.11(a), 11.13 and 11.14 shall survive termination.


                                      -15-
<PAGE>

10. NON-ASSIGNABILITY.

      10.1 Non-Assignability. This Agreement is personal to BMS and is not
assignable by BMS. PROGENICS may not assign its rights hereunder (other than to
any assignee of all or substantially all of its business, which assignee has
previously agreed to be bound by all of the terms and conditions of this
Agreement). Any purported assignment not in accordance with this Section 10.1
shall be ineffective.

11. MISCELLANEOUS.

      11.1 Relationship of Parties. Nothing in this Agreement is intended or
shall be deemed to constitute a partnership, agency, employer-employee or joint
venture relationship between the Parties. No Party shall incur any debts or make
any commitments for the other, except to the extent, if at all, specifically
provided herein.

      11.2 Force Majeure. Neither Party shall be liable to the other for loss or
damages or shall have any right to terminate this Agreement for any default or
delay attributable to any act of God, flood, fire, explosion, strike, lockout,
labor dispute, shortage of raw materials, casualty or accident, war, revolution,
civil commotion, act of public enemies, blockage or embargo, injunction, law,
order, proclamation, regulation, ordinance, demand or requirement of any
government or subdivision, authority or representative of any such government,
or any other cause beyond the reasonable control of such Party, if the Party
affected shall give prompt notice of any such cause to the other Party. The
Party giving such notice shall thereupon be excused from such of its obligations
hereunder as it is thereby disabled from performing for so long as it is so
disabled and for 30 days thereafter. Notwithstanding the foregoing, nothing in
this Section 11.2 shall excuse or suspend the obligation to make any payment due
hereunder in the manner and at the time provided.

      11.3 Further Actions. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all such other acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

      11.4 Notice. Any notice or request required or permitted to be given under
or in connection with this Agreement shall be deemed to have been sufficiently
given if in writing and personally delivered by messenger, facsimile
transmission (receipt verified), express courier service (signature required),
or telegram, prepaid, to the Party for which such notice is intended, at the
address set forth for such Party below:


                                      -16-
<PAGE>

               (a)   In the case of PROGENICS, to:

                           Progenics Pharmaceuticals, Inc.
                           777 Old Saw Mill River Road
                           Tarrytown, New York 10591
                           Attention: Dr. Paul Maddon
                           Facsimile No.: (914) 789-2817

               (b)   In the case of BMS, to:

                           Bristol-Myers Squibb Company
                           P.O. Box 4000
                           Route 206 & Province Line Road
                           Princeton, New Jersey 08543-4000
                           Attention: Vice President and Senior
                           Counsel, Pharmaceutical Research
                           Institute, and Worldwide Franchise
                           Management and Strategic Business
                           Development
                           Facsimile No.: (609) 252-4232

               (c)   In the case of The Regents, to:

                           The Regents of the University of California
                           Business Research Partnerships
                           Box 951525, 1106 Ueberroth Building
                           University of California, Los Angeles
                           Los Angeles, California  90095-1525
                           Attention: Fredrica S. Reiter
                           Facsimile No.: (310) 206-3619

or to such other address for such Party as it shall have specified by like
notice to the other Party, provided that notices of a change of address shall be
effective only upon receipt thereof. If sent by messenger, facsimile
transmission, express courier service, or telegram, the date of mailing or
transmission shall be deemed to be the date on which such notice or request has
been given.

      11.5 Use of Name. Neither Party is permitted to use any name, trade name,
trademark or other designation of the other Party (and, in the case of BMS, of
The Regents) or its employees (including contraction, abbreviation or simulation
of any of the foregoing) in advertising, publicity or other promotional
activity. Unless required by law, BMS is expressly prohibited from using the
name "The Regents of the University of California" or the name of any campus of
the University of California.

      11.6 Marking. BMS, its Affiliates and its Sub-sublicensees shall mark all
Regents' Products made, used or sold under the terms of this Agreement, or their
containers, in accordance with the applicable patent marking laws.


                                      -17-
<PAGE>

      11.7 Costs and Expenses. Except as otherwise expressly provided in this
Agreement, each Party shall bear all costs and expenses associated with the
performance of such Party's obligations under this Agreement.

      11.8 Manufacture in United States. Because this Agreement grants an
exclusive right to a particular use of the Invention, BMS, its Affiliates and
its Sub-sublicensees must manufacture in the United States any products
embodying the Invention or produced through the Invention's use to the extent
required by 35 U.S.C. ss.ss.201-212.

      11.9 Waiver. A waiver by either Party of any of the terms and conditions
of this Agreement in any instance shall not be deemed or construed to be a
waiver of such term or condition for the future, or of any subsequent breach
hereof. All rights, remedies, undertakings, obligations and agreements contained
in this Agreement shall be cumulative and none of them shall be in limitation of
any other remedy, right, undertaking, obligation or agreement of either Party.

      11.10 Compliance with Law.

            (a) BMS, its Affiliates and its Sub-sublicensees must observe all
applicable United States and foreign laws with respect to the transfer of
Regents' Products and related technical data to foreign countries, including the
International Traffic in Arms Regulations (ITAR) and the Export Administration
Regulations.

            (b) If this Agreement or any associated transaction is required by
the law of any nation to be either approved or registered with any governmental
agency, BMS will assume all legal obligations to do so. BMS will notify
PROGENICS if it becomes aware that this Agreement is subject to a United States
or foreign government reporting or approval requirement. BMS will make all
necessary filings and pay all costs including fees, penalties, and all other
out-of-pocket costs associated with such reporting or approval process.

      11.11 Severability. When possible, each provision of this Agreement will
be interpreted in such manner as to be effective and valid under applicable law,
but if any provision of this Agreement is held to be prohibited by or invalid
under applicable law, such provision will be ineffective only to the extent of
such prohibition or invalidity, without invalidating the remainder of this
Agreement.

      11.12 Amendment. No amendment, modification or supplement of any
provisions of this Agreement shall be valid or effective unless made in writing
and signed by a duly authorized officer of each Party.


                                      -18-
<PAGE>

      11.13 Governing Law. THIS AGREEMENT IS TO BE INTERPRETED AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF CALIFORNIA, but the scope and validity
of any patent or patent application will be governed by the applicable laws of
the country of the patent or patent application.

      11.14 Arbitration. Any dispute arising out of or relating to any
provisions of this Agreement (including, without limitation, Section 5) shall be
finally settled by arbitration to be held in Los Angeles, California, under the
auspices and then current licensing agreement arbitration rules of the American
Arbitration Association. Such arbitration shall be conducted by three
arbitrators appointed according to said rules. Judgment upon any award rendered
may be entered in any court having jurisdiction, or application may be made to
such court for a judicial acceptance of the award and an order of enforcement,
as the case may be.

      11.15 Counterparts. This Agreement may be executed simultaneously in any
number of counterparts, any one of which need not contain the signature of more
than one Party but all such counterparts taken together shall constitute one and
the same agreement.

      11.16 Descriptive Headings. The descriptive headings of this Agreement are
for convenience only, and shall be of no force or effect in construing or
interpreting any of the provisions of this Agreement.


                                      -19-
<PAGE>

      IN WITNESS WHEREOF, each of the Parties has caused this Agreement to be
executed and delivered by its duly authorized officer as of the day and year
first above written.


                                      PROGENICS PHARMACEUTICALS, INC.


                                      By: /s/ Paul J. Maddon
                                         -----------------------------------
                                      Name:  Paul J. Maddon, M.D., Ph.D.
                                      Title: Chairman and Chief
                                               Executive Officer

                                      BRISTOL-MYERS SQUIBB COMPANY


                                      By: /s/ Charles Linzner
                                         -----------------------------------
                                      Name:  Charles Linzner
                                      Title: Vice President


                                      -20-


<PAGE>

                                                                   Exhibit 10.26


                              SUBLICENSE AGREEMENT
                 WITH RESPECT TO AQUILA BIOPHARMACEUTICALS, INC.
                          LICENSE AND SUPPLY AGREEMENT

                                     BETWEEN

                         PROGENICS PHARMACEUTICALS, INC.

                                       AND

                          BRISTOL-MYERS SQUIBB COMPANY

                                   DATED AS OF

                                 APRIL 15, 1997


[Note: Certain portions of this document have been marked "[XXX]" to 
indicate that confidentiality has been requested for this information. The 
confidential portions have been omitted and filed separately with the 
Securities and Exchange Commission.]

<PAGE>

                               TABLE OF CONTENTS

                                                                            Page
                                                                            ----
1.    DEFINITIONS ..........................................................   1
      1.1    "Adjuvant .....................................................   2
      1.2    "Affiliate" ...................................................   2
      1.3    "Agreement" ...................................................   2
      1.4    "Aquila Field of Use" .........................................   2
      1.5    "Aquila Knowhow" ..............................................   2
      1.6    "Aquila Licensed Patent Rights" ...............................   2
      1.7    "Aquila Licensed Product" .....................................   3
      1.8    "Aquila Licensed Territory" ...................................   3
      1.9    "cGLPs" .......................................................   3
      1.10   "cGMPs" .......................................................   3
      1.11   "Commercial Introduction" .....................................   3
      1.12   "Effective Date" ..............................................   3
      1.13   "FDA" .........................................................   3
      1.14   "GD2" .........................................................   3
      1.15   "Generic Product" .............................................   3
      1.16   "GM2" .........................................................   4
      1.17   "GMK Vaccine" .................................................   4
      1.18   "KLH" .........................................................   4
      1.19   "Manufacture" .................................................   4
      1.20   "MGV Vaccine" .................................................   4
      1.21   "Net Sales" ...................................................   4
      1.22   "Party" and "Parties" .........................................   4
      1.23   "Person" ......................................................   4
      1.24   "PLA" .........................................................   4
      1.25   "PLA-Enabling Human Clinical Trial" ...........................   5
      1.26   "Sub-sublicensees" ............................................   5
      1.27   "Term" ........................................................   5
      1.28   "Third Party" .................................................   5
      1.29   "Valid Claim" .................................................   5
                                                          
2.    REPRESENTATIONS AND WARRANTIES OF PROGENICS ..........................   5
      2.1    Representations and Warranties ................................   5

3.    LICENSE ..............................................................   6
      3.1    Grant of Sublicense Rights ....................................   6
      3.2    Sublicenses ...................................................   6
      3.3    On-Going Transfer of Aquila Knowhow and Aquila Licensed           
             Patent Rights .................................................   7
      3.4    BMS Rights under Aquila/PROGENICS License and Supply              
             Agreement .....................................................   7
                                                                              
4.    UPFRONT FEE; ROYALTIES ...............................................   8
      4.1    Upfront Fee ...................................................   8
      4.2    Royalties .....................................................   8
      4.3    Obligation to Pay Royalties ...................................  12


                                      (i)
<PAGE>

                          TABLE OF CONTENTS (continued)

                                                                            Page
                                                                            ----
5.    DUE DILIGENCE ........................................................  12
      5.1    Maintenance of License ........................................  12
      5.2    Pre-Clinical and Clinical Programs ............................  13
                                                  
6.    ROYALTY PAYMENTS, REPORTS AND RECORDS ................................  13
      6.1    Commercial Introduction .......................................  13
      6.2    Reports; Payments .............................................  13
      6.3    Mode of Payment; Taxes ........................................  13
      6.4    Records Retention .............................................  14
      6.5    Audit Request .................................................  14
      6.6    Cost of Audit; Discrepancies ..................................  14
      6.7    No Non-Monetary Consideration for Sales .......................  15
                                                                     
7.    MANUFACTURE AND SUPPLY ...............................................  15
      7.1    Retained Right of Aquila ......................................  15

8.    PATENTS PROSECUTION; ENFORCEMENT .....................................  15
      8.1    Patent Prosecution ............................................  15
      8.2    Patent Costs ..................................................  15
      8.3    Patent Enforcement ............................................  15
                                   
9.    TERM; TERMINATION ....................................................  16
      9.1    Term ..........................................................  16
      9.2    Material Breach ...............................................  16
      9.3    Effect of Termination .........................................  16
      9.4    Right to Sell Stock on Hand ...................................  17
      9.5    Termination of Sublicenses ....................................  17
      9.6    Accrued Rights; Surviving Obligations .........................  17
                                                                        
10.   ARBITRATION ..........................................................  17
      10.1   Arbitration ...................................................  17

11.   MISCELLANEOUS PROVISIONS .............................................  18
      11.1   No Partnership ................................................  18
      11.2   Assignments ...................................................  18
      11.3   Further Actions ...............................................  19
      11.4   No Name or Trademark Rights ...................................  19
      11.5   Force Majeure .................................................  19
      11.6   Severability ..................................................  19
      11.7   Amendments ....................................................  19
      11.8   Captions ......................................................  20
      11.9   Applicable Law ................................................  20
      11.10  Notices and Deliveries ........................................  20
      11.11  Counterparts ..................................................  21
      11.12  Compliance with Laws ..........................................  21
                                                

                                      (ii)
<PAGE>

                         TABLE OF CONTENTS (continued)

                                                                            Page
                                                                            ----
                                    EXHIBITS

                  Exhibit A        Aquila Licensed Patent Rights


                                     (iii)
<PAGE>

                              SUBLICENSE AGREEMENT
                             WITH RESPECT TO AQUILA
              BIOPHARMACEUTICALS, INC. LICENSE AND SUPPLY AGREEMENT

      THIS SUBLICENSE AGREEMENT WITH RESPECT TO AQUILA BIOPHARMACEUTICALS, INC.
LICENSE AND SUPPLY AGREEMENT (this "Agreement") is dated as of April 15, 1997
(the "Effective Date") between Progenics Pharmaceuticals, Inc., a Delaware
corporation, having offices at 777 Old Saw Mill River Road, Tarrytown, New York
10591 ("PROGENICS"), and Bristol-Myers Squibb Company, a Delaware corporation,
having offices at P.O. Box 4000, Route 206 and Province Line Road, Princeton,
New Jersey 08543-4000, for and on behalf of itself and its Affiliates ("BMS")
(each singularly a "Party" and collectively the "Parties") with reference to the
following:

                             PRELIMINARY STATEMENTS

      A. PROGENICS has acquired a license to certain patents and technology
relating to the an adjuvant [XXX] pursuant to a license and supply agreement
dated August 31, 1995 (the "Aquila/PROGENICS License and Supply Agreement")
between PROGENICS and Aquila Biopharmaceuticals, Inc., a corporation in the
State of Delaware ("Aquila"), formerly known as Cambridge Biotech Corporation.

      B. BMS is interested in obtaining a worldwide sublicense to formulate,
manufacture, use and sell products using the patent rights and technology to
which PROGENICS has acquired a license from Aquila, and PROGENICS wishes to
grant such rights to BMS, pursuant to the terms and conditions set forth in this
Agreement.

      C. It is anticipated that BMS and Aquila will enter into a Supply
Agreement pursuant to which it is contemplated that BMS will purchase from
Aquila, and Aquila will supply to BMS, 100% of BMS' requirements for Adjuvant on
the terms and conditions to be stated therein.

      D. It is anticipated that BMS, PROGENICS and Aquila will enter into a side
letter agreement (the "Aquila Letter Agreement") with respect to this Agreement
and the Aquila/PROGENICS License and Supply Agreement, and the rights and
obligations of such parties hereunder and thereunder.

      NOW, THEREFORE, in consideration of the mutual covenants and agreements of
the Parties contained in this Agreement, the Parties agree as follows:

1. DEFINITIONS.

      The following terms shall have the following meanings for purposes of this
Agreement:
<PAGE>

      1.1 "Adjuvant" [XXX].

      1.2 "Affiliate" means with respect to any Party, shall mean any Person
which, directly or indirectly, controls, is controlled by, or is under common
control with, such Party. For these purposes, "control" shall refer to the
possession, directly or indirectly, of the power to direct the management or
policies of a Person or to veto any material decision relating to the management
or policies of a Person, in each case, whether through the ownership of equity
participation, voting securities or beneficial interests, by contract, by
agreement, or otherwise.

      1.3 "Agreement" means this Sublicense Agreement, including any exhibits,
schedules or other attachments thereto, as any of the foregoing may be validly
amended from time to time.

      1.4 "Aquila Field of Use" means vaccines containing purified GM2 and GD2
preparations (whether alone or in combination with each other) for the
prevention or treatment of human cancers.

      1.5 "Aquila Knowhow" means materials, data, results, formulae, designs,
specifications, methods, processes, improvements, techniques, ideas,
discoveries, technical information, process information, clinical information
and any other information, whether or not any of the foregoing is patentable,
known to and which is confidential and proprietary to Aquila now or hereafter
during the Term, to the extent that any of the foregoing relates to an Aquila
Licensed Patent Rights or the development, manufacture, use or sale of Adjuvant
in connection with the development, manufacture, use or sale of any Aquila
Licensed Product; provided, however, that the term "Aquila Knowhow" shall not
include any of the foregoing that is subject to proprietary rights of Third
Parties.

      1.6 "Aquila Licensed Patent Rights" means any and all patent applications
and patents (including inventor's certificates and utility models) throughout
the world, including any substitutions,


                                      -2-
<PAGE>

extensions, reissues, reexaminations, renewals, divisions, continuations and
continuations-in-part of the foregoing, which Aquila now or hereafter during the
Term owns or controls (solely or jointly) or under which Aquila has the right to
grant sublicenses (regardless of any royalty or other payments to a third party
required of Aquila), to the extent that any of the foregoing covers, in whole or
in part, the development, manufacture, use or sale of Adjuvant in connection
with the development, manufacture, use or sale of any Aquila Licensed Product.
"Aquila Licensed Patent Rights" shall include, without limitation, the patent
listed on Exhibit A attached and incorporated into this Agreement.

      1.7 "Aquila Licensed Product" means any vaccine or vaccines formulated
using Aquila Licensed Patent Rights or Aquila Knowhow in the Field of Use.

      1.8 "Aquila Licensed Territory" means the world.

      1.9 "cGLPs" means the current Good Laboratory Practices for Finished
Pharmaceuticals pursuant to 21 C.F.R. 58 et seq., as amended from time to time.

      1.10 "cGMPs" means the current Good Manufacturing Practices for Finished
Pharmaceuticals pursuant to 21 C.F.R. 210 et seq., as amended from time to time.

      1.11 "Commercial Introduction" means, in each country of the Territory,
the date that Aquila Licensed Product(s) are first sold, marketed or publicly
made available for sale. Aquila Licensed Products distributed or used for
clinical trials or experimental purposes only shall not be considered sold,
marketed or made publicly available and shall not establish the First Commercial
Sale.

      1.12 "Effective Date" is defined in the introductory paragraph.

      1.13 "FDA" means the United States Food and Drug Administration, or the
successor thereto.

      1.14 "GD2" means [XXX].

      1.15 "Generic Product" shall mean, on a country-by-country basis, an
Aquila Licensed Product: (i) the manufacture, use or sale of which is not
covered by a Valid Claim in such country, and (ii) that is also marketed by an
unlicensed Third Party or Parties in such country, which Third Party or Parties
have, in the aggregate,


                                      -3-
<PAGE>

at least [XXX] of the unit volume of sales for such Aquila Licensed Product in 
any calendar quarter in such country, as measured by IMS.

      1.16 "GM2" means [XXX].

      1.17 "GMK Vaccine" means that certain Aquila Licensed Product composed of
GM2 conjugated to KLH and combined with Adjuvant.

      1.18 "KLH" means keyhole limpet hemocyanin.

      1.19 "Manufacture" means the aseptic storage, handling, production,
processing and packaging of Adjuvant in accordance with this Agreement.

      1.20 "MGV Vaccine" means that certain Aquila Licensed Product composed of
GM2 conjugated to KLH and combined with GD2 conjugated to KLH and further
combined with Adjuvant.

      1.21 "Net Sales" shall mean the gross amount invoiced by BMS [XXX]. Such
amounts shall be determined from the books and records of BMS, its Affiliates or
Sub-sublicensees, maintained in accordance with the accounting principles used
by such entity, consistently applied.

      1.22 "Party" and "Parties" are defined in the introductory paragraph.

      1.23 "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, or any organization which can exercise independent legal standing.

      1.24 "PLA" means a Product License Application filed with the FDA.


                                      -4-
<PAGE>

      1.25 "PLA-Enabling Human Clinical Trial" means as to a specific Aquila
Licensed Product, a controlled and lawful study of the efficacy of such Aquila
Licensed Product by administration of such Aquila Licensed Product to human
beings where the principal purpose of such trial is to provide statistically
significant efficacy data to serve pivotal support for an application to the FDA
for approval of a Aquila Licensed Product for the indication being investigated
by the trial.

      1.26 "Sub-sublicensees" shall mean any Third Party sublicensed by BMS to
make, have made, use, sell, or have sold any Aquila Licensed Product or to
practice any Aquila Licensed Patent Rights.

      1.27 "Term" is defined in Section 9.1.

      1.28 "Third Party" shall mean any Person who or which is neither a Party
nor an Affiliate of a Party.

      1.29 "Valid Claim" means a claim of any Aquila Licensed Patent Rights
which has not been held invalid, unpatentable or unenforceable in an
unappealable decision of a court or other governmental body of competent
jurisdiction, which has not been rendered unenforceable through disclaimer or
otherwise, and which has not been lost through an interference proceeding.

2. REPRESENTATIONS AND WARRANTIES OF PROGENICS.

      2.1 Representations and Warranties. PROGENICS represents and warrants to
BMS as of the Effective Date as follows:

            (a) The Aquila/PROGENICS License and Supply Agreement is in full
force and effect and has not been modified or amended;

            (b) To the best of PROGENICS's knowledge, neither Aquila nor
PROGENICS is in default under, and neither party claims or has grounds upon
which to claim the other party is in default under, the Aquila/PROGENICS License
and Supply Agreement;

            (c) To the best of PROGENICS's knowledge, the rights Aquila has
licensed to PROGENICS pursuant to the Aquila/PROGENICS License and Supply
Agreement were not and are not subject to any restrictions or limitations except
as set forth in the Aquila/PROGENICS License and Supply Agreement;

            (d) To the best of PROGENICS's knowledge, Aquila has not accepted
funding from any non-governmental parties which would diminish PROGENICS's
rights to technology under the Aquila/PROGENICS License and Supply Agreement;


                                      -5-
<PAGE>

            (e) The milestones set forth in Sections 5.1(a), 5.1(b) and 5.1(e)
of the Aquila/PROGENICS License and Supply Agreement have been fully satisfied
by PROGENICS as of the date of this Agreement; and

            (f) Attached as Exhibit A is a true and complete list of all patents
and patent applications comprising the Aquila Licensed Patent Rights as of the
Effective Date.

3. LICENSE.

      3.1 Grant of Sublicense Rights. Pursuant to Section 2.2 of the
Aquila/PROGENICS License and Supply Agreement, PROGENICS hereby grants BMS a
non-exclusive, worldwide sublicense under the Aquila License and Supply
Agreement to use the Aquila Knowhow and practice the Aquila Licensed Patent
Rights to develop, manufacture, have manufactured, use, sell, and have sold
Aquila Licensed Products.

      3.2 Sublicenses.

            (a) BMS shall have the right to grant to its Affiliates sublicenses
of its rights under this Agreement with respect to Aquila Licensed Products (but
not the Adjuvant alone) (a "Sublicense") only for purposes of manufacturing
and/or marketing the Aquila Licensed Products developed by or under continuing
development by PROGENICS, provided that (i) BMS shall guarantee and be
responsible for the making of all payments due, and the making of reports under
this Agreement, by reason of sales of any Aquila Licensed Products by its
Affiliates and their compliance with all applicable terms of this Agreement; and
(ii) each Affiliate must agree in writing to keep books and records and permit
PROGENICS to review such books and records pursuant to the relevant provisions
and to observe all other applicable terms of this Agreement. No consent or
approval of PROGENICS shall be required in connection with the granting of such
sublicenses.

            (b) BMS shall have the right to grant Sublicenses to
Sub-sublicensees only for purposes of manufacturing and/or marketing the Aquila
Licensed Products developed by or under continuing development by PROGENICS,
except that BMS does not have the right to grant such sublicenses with respect
to the United States, provided that (i) PROGENICS's consent thereto shall be
required, which consent shall not be unreasonably withheld (it will be
reasonable for PROGENICS to withhold consent if PROGENICS determines that the
capabilities of the proposed Sub-sublicensee are not comparable to BMS's
capabilities in the country or countries to be sublicensed); (ii) BMS shall
guarantee and be responsible for the making of all payments due, and the making
of reports under this Agreement, by reason of sales of any Aquila Licensed
Products by its Sub-sublicensees and their compliance with all applicable terms
of this Agreement; and (iii) each Sub-sublicensee must agree in writing to


                                      -6-
<PAGE>

keep books and records and permit PROGENICS to review such books and records
pursuant to the relevant provisions and to observe all other applicable terms of
this Agreement.

            (c) BMS hereby unconditionally guarantees the performance of any of
its Affiliates and Sub-sublicensees hereunder. In the event of a breach by an
Affiliate or Sub-sublicensee in the observance of applicable terms of this
Agreement, PROGENICS shall be entitled to proceed against either such Affiliate
or Sub-sublicensee or directly against BMS, as PROGENICS may determine in its
sole discretion, to enforce this Agreement.

      3.3 On-Going Transfer of Aquila Knowhow and Aquila Licensed Patent Rights.
PROGENICS shall promptly transfer to BMS existing Aquila Knowhow and Aquila
Licensed Patent Rights in PROGENICS's possession or control for purposes of
BMS's research and development (including but not limited to preclinical trials
and human clinical trials but excluding Aquila Knowhow relating to the
Manufacture of the Adjuvant) with respect to Aquila Licensed Products. On an
on-going basis during the Term, PROGENICS shall disclose to BMS in writing any
and all Aquila Knowhow (exclusive of Aquila Knowhow relating to the
Manufacturing the Adjuvant) then existent, whether or not potentially
patentable, and any and all Aquila Licensed Patent Rights then existent promptly
after the same is identified and disclosed by Aquila pursuant to the
Aquila/PROGENICS License and Supply Agreement.

      3.4 BMS Rights under Aquila/PROGENICS License and Supply Agreement.
PROGENICS agrees that, with respect to the Aquila/PROGENICS License and Supply
Agreement:

            (a) PROGENICS will diligently fulfill all of its obligations
thereunder, to the extent such obligations have not been delegated to BMS;

            (b) PROGENICS shall not enter into any subsequent agreement with
Aquila which modifies or amends the Aquila/PROGENICS License and Supply
Agreement in a way which is deleterious to the rights of BMS under this
Agreement;

            (c) PROGENICS shall not terminate the Aquila/PROGENICS License and
Supply Agreement, in whole or in part, directly or indirectly, without the prior
written consent of BMS, which shall not be unreasonably withheld in the event
that Aquila is in material default under the terms thereof at the time PROGENICS
seeks to make such exercise;

            (d) PROGENICS shall promptly furnish BMS with copies of all reports
it receives from Aquila which relate to the subject of this Agreement;


                                      -7-
<PAGE>

            (e) PROGENICS shall promptly furnish BMS with copies of all reports
PROGENICS furnishes to Aquila which relate to the subject of this Agreement;

            (f) PROGENICS shall furnish to BMS copies of all notices received by
PROGENICS relating to alleged breaches or defaults by PROGENICS of its
obligations under the Aquila/PROGENICS License and Supply Agreement within three
business days of PROGENICS's receipt thereof and, provided that PROGENICS cannot
or chooses not to cure or otherwise resolve such alleged breaches or defaults,
PROGENICS shall allow BMS, in BMS's sole discretion, to cure or otherwise
resolve such alleged breaches or defaults in order to preserve BMS's rights
under this Agreement.

4. UPFRONT FEE; ROYALTIES.

      4.1 Upfront Fee. As consideration to PROGENICS for the issuance of the
sublicense and other rights to BMS under this Agreement, BMS shall pay to
PROGENICS the sum of: [XXX]. Such up-front fee shall be paid upon the execution
of this Agreement by both Parties. Such sum shall be non-refundable.

      4.2 Royalties. Subject to the other terms of this Agreement, as
consideration to PROGENICS for the grant of the sublicense and other rights to
BMS under this Agreement, during the term of this Agreement, BMS shall pay to
PROGENICS royalties on Net Sales of any Aquila Licensed Product commencing on
the Commercial Introduction of such Aquila Licensed Product by BMS, its
Affiliates or its Sub-sublicensees as follows:

            (a) With respect to the GMK Vaccine:

                  (i) With respect to those countries in the Territory where
such Aquila Licensed Product is covered by a Valid Claim in such countries
(unless the Aquila Licensed Patent Rights existing in any such country are not
sufficient to afford such Aquila Licensed Product sufficient protection from
competition by a vaccine in the Aquila Field of Use manufactured by a Third
Party using an adjuvant based on [XXX] and such Third Party holds at least 
[XXX] of the market for such vaccine in the Field of Use in any such country,
based on unit volume of sales as measured by IMS (a "Competing Product"), in
which case subparagraph (ii) below shall apply):

                        (A) [XXX] of the Net Sales of such Aquila Licensed
                  Product in such countries for any calendar year until Net
                  Sales throughout the


                                      -8-
<PAGE>

                  Territory in such calendar year equal [XXX]; and

                        (B) After Net Sales of such Aquila Licensed Product
                  throughout the Territory in such calendar year exceed [XXX] of
                  any further Net Sales of such Licensed Product in such
                  countries until the end of such calendar year.

                  (ii) With respect to those countries in the Territory where
such Aquila Licensed Product is not covered by a Valid Claim in any such country
or there is a Competing Product in any such country (unless the Aquila Licensed
Product is a Generic Product in any such country, in which case subparagraph
(iii) below shall apply):

                        (A) [XXX] of the Net Sales of such Aquila Licensed
                  Product in such countries for any calendar year until Net
                  Sales throughout the Territory in such calendar year equal
                  [XXX]; and

                        (B) After Net Sales of such Aquila Licensed Product
                  throughout the Territory in such calendar year exceed [XXX] of
                  any further Net Sales of such Licensed Product in such
                  countries until the end of such calendar year.

                  (iii) With respect to those countries in the Territory where
such Aquila Licensed Product is a Generic Product:

                        (A) [XXX] of the Net Sales of such Licensed Product in
                  such countries for any calendar year until Net Sales
                  throughout the Territory in such calendar year equal [XXX]; 
                  and

                        (B) After Net Sales of such Aquila Licensed Product
                  throughout the Territory in such calendar year exceed [XXX] of
                  any further Net Sales of such Licensed Product in such
                  countries until the end of such calendar year.

                  (iv) Royalties shall be paid at the royalty rates set forth in
Sections 4.2(a)(i)(A), 4.2(a)(ii)(A) and 4.2(a)(iii)(A) through the end of the
calendar quarter preceding the calendar quarter in which annual Net Sales in all
countries throughout the Territory first exceed [XXX] in any year. Royalties 
shall be


                                      -9-
<PAGE>

paid at the royalty rates set forth in Sections 4.2(a)(i)(B), 4.2(A)(ii)(B) and
4.2(a)(iii)(B) for the calendar quarter in which annual Net Sales in all
countries throughout the Territory first exceed [XXX] in any year, and for each
calendar quarter in such year thereafter other than the last calendar quarter of
such year. Following the end of the last calendar quarter of each year, the
total amount of royalties actually due for such year shall be calculated as
provided in Section 4.2(a)(v), and such amount of royalties shall be paid,
reduced by the total amount of royalties paid with respect to such Aquila
Licensed Product throughout the Territory for the first three calendar quarters
of such year. The calculation of the amount to be paid with respect to the
fourth calendar quarter of each year shall be included on the royalty report for
such calendar quarter. In the event that BMS has paid more royalties during the
first three calendar quarters of any year than BMS owes for the entire year, BMS
shall be entitled to a credit, equal to the amount of such excess royalties
paid, to be applied against [XXX] of accrued royalties until the entire credit
has been used.

                  (v) The total amount of royalties actually due under this
Section 4.2(a) shall be calculated as follows:

                        (A) The royalty rate set forth in Section 4.2(a)(i)(A)
                  shall be applied to that amount of Net Sales of such Aquila
                  Licensed Product determined under the formula X(1) x Y(1)/Z;

                        (B) The royalty rate set forth in Section 4.2(a)(i)(B)
                  shall be applied to that amount of Net Sales of such Aquila
                  Licensed Product determined under the formula X(2) x Y(1)/Z;

                        (C) The royalty rate set forth in Section 4.2(a)(ii)(A)
                  shall be applied to that amount of Net Sales of such Aquila
                  Licensed Product determined under the formula X(1) x Y(2)/Z;

                        (D) The royalty rate set forth in Section 4.2(a)(ii)(B)
                  shall be applied to that amount of Net Sales of such Aquila
                  Licensed Product determined under the formula X(2) x Y(2)/Z;

                        (E) The royalty rate set forth in Section 4.2(a)(iii)(A)
                  shall be applied to that amount of Net Sales of such Aquila
                  Licensed Product determined under the formula X(1) x Y(3)/Z;
                  and

                        (F) The royalty rate set forth in Section 4.2(a)(iii)(B)
                  shall be applied to that amount of Net Sales of such Aquila
                  Licensed Product determined under the formula X(2) x Y(3)/Z;


                                      -10-
<PAGE>

            Where:

            X(1)   =    the smaller of: (i) the actual annual Net Sales of such
                        Aquila Licensed Product throughout the Territory for
                        such year, or (ii) [XXX]
                  
            X(2)   =    the actual annual Net Sales of such Aquila Licensed
                        Product throughout the Territory for such year in excess
                        of [XXX]
                  
            Y(1)   =    the annual Net Sales of such Aquila Licensed Product for
                        such year in all countries when Section 4.2(a)(i)
                        applies
                  
            Y(2)   =    the annual Net Sales of such Aquila Licensed Product for
                        such year in all countries when Section 4.2(a)(ii)
                        applies
                  
            Y(3)   =    the annual Net Sales of such Aquila Licensed Product for
                        such year in all countries when Section 4.2(a)(iii)
                        applies
                  
            Z      =    the annual Net Sales of such Aquila Licensed Product for
                        such year in all countries in the Territory
                 
            (b) With respect to the MGV Vaccine and any other Aquila Licensed 
Products:

                  (i) With respect to those countries in the Territory where
such Aquila Licensed Product is covered by a Valid Claim in such country [XXX] 
of the Net Sales of such Aquila Licensed Product in such countries for any
calendar year (unless there is a Competing Product in that country, in which
case subparagraph (ii) below shall apply).

                  (ii) With respect to those countries in the Territory where
such Aquila Licensed Product is not covered by a Valid Claim in such country or
there is a Competing Product in any such country (unless the Aquila Licensed
Product is a Generic Product in any such country, in which case subparagraph
(iii) below shall apply), [XXX] of the Net Sales of such Aquila Licensed Product
in such country for any calendar year.

                  (iii) With respect to each country in the Territory where such
Aquila Licensed Product is a Generic Product, [XXX] of the Net Sales of such 
Aquila Licensed Product in such country for any calendar year.


                                      -11-
<PAGE>

            (c) The royalty rates applicable to Aquila Licensed Products not
covered by a Valid Claim or where there is a Competing Product pursuant to
Sections 4.2(a)(ii) and 4.2(b)(ii), respectively, shall apply to Net Sales in
any country commencing with the calendar quarter during which such Aquila
Licensed Product is first not covered by a Valid Claim, or is first subject to a
Competing Product, in such country.

            (d) The royalty rates applicable to Generic Products pursuant to
Sections 4.2(a)(iii) and 4.2(b)(iii), respectively, shall apply to Net Sales in
any country commencing with the calendar quarter during which such Aquila
Licensed Product first becomes a Generic Product in such country.

      4.3 Obligation to Pay Royalties. The obligation to pay royalties to
PROGENICS under Section 4.2 is imposed only once with respect to the same unit
of Aquila Licensed Product regardless of the number of Aquila Licensed Patents
Rights pertaining thereto. BMS shall only be entitled to a credit against
royalties or a reduction of the royalty rate once with respect to any Aquila
Licensed Product in any country pursuant to any provision in this Agreement.
There shall be no obligation to pay royalties to PROGENICS under Section 4.2 on
sales of Aquila Licensed Products among BMS, its Affiliates and
Sub-sublicensees, but in such instances the obligation to pay royalties shall
arise upon the sale by BMS, its Affiliates or Sub-sublicensees to Third Parties.
Payments due under Section 4.2 shall be deemed to accrue when Aquila Licensed
Products are shipped or billed, whichever event shall first occur. In the
instance where BMS, its Affiliates or Sub-sublicensees use the Aquila Licensed
Product or provide it as part of some other service or product, a royalty shall
be due to PROGENICS at the time such Aquila Licensed Product is used or provided
based on a Net Sales amount equal to the price at which BMS or its Affiliate or
Sub-sublicensee sell such Aquila Licensed Product to Third Parties in the
country in which the Aquila Product was used or provided.

5. DUE DILIGENCE.

      5.1 Maintenance of License. In order to maintain the sublicense granted
pursuant to Section 3.1 with respect to a designated Aquila Licensed Product,
BMS agrees to:

            (a) [XXX]; and

            (b) [XXX].

            If BMS shall fail to achieve any of the above objectives and such
failure shall remain unremedied for a period of 50 days


                                      -12-
<PAGE>

after notice of such failure to BMS by PROGENICS (the "Grace Period"), this
license shall automatically terminate at the end of the Grace Period (except
with respect to the first Aquila Licensed Product if BMS has fulfilled the
obligations set forth in this Section 5.1). Notwithstanding the foregoing, if
such failure is a result of BMS's not having obtained a Third Party license
necessary to make, use or sell Aquila Licensed Products and reasonable evidence
is submitted by BMS to PROGENICS that such license can be obtained in a
reasonable period of time, PROGENICS shall request from Aquila that the Grace
Period be extended for a period of time set forth in the request.
Notwithstanding the foregoing, PROGENICS shall not have the right to terminate
the license for failure of BMS to meet a goal if such failure is a result of:
(i) PROGENICS's failure to meet its obligations hereunder, or (ii) an action
brought by a Third Party claiming that the use of the Adjuvant in Aquila
Licensed Products infringed a patent of such Third Party.

      The parties acknowledge and agree that the milestones contained in this
Section 5.1 were established on the assumption that the milestones would apply
to development of the GMK Vaccine. In the event that development of the GMK
Vaccine is terminated due to safety or efficacy reasons, the parties agree that
the milestones set forth in this Section 5.1 shall not apply and the parties
will negotiate in good faith to establish new milestones.

      5.2 Pre-Clinical and Clinical Programs. BMS and PROGENICS or their
respective Affiliates or Sub-sublicensees or sublicensees, as the case may be,
shall conduct preclinical and clinical testing with respect to all Aquila
Licensed Products, and otherwise shall be responsible for the development
thereof, in accordance with the terms of this Agreement.

6. ROYALTY PAYMENTS, REPORTS AND RECORDS.

      6.1 Commercial Introduction. BMS shall promptly give PROGENICS notice of
the occurrence of Commercial Introduction of each Aquila Licensed Product.

      6.2 Reports; Payments. Except as otherwise specifically provided in this
Agreement, all payments due under this Agreement shall be paid quarterly within
50 days after the end of each calendar quarter. Each such payment for running
royalties shall be accompanied by a statement, Aquila Licensed Product-by-Aquila
Licensed Product and country-by-country, of the amount of Net Sales during such
quarter and the amount of royalties due on such Net Sales and, with respect to
the last calendar quarter of each year, such report shall include the
calculation of the adjustments referred to in Section 4.2(a)(iv).

      6.3 Mode of Payment; Taxes. All payments due under this Agreement shall be
paid by wire transfer of funds to an account at


                                      -13-
<PAGE>

PROGENICS's designated bank in New York, New York, and shall be paid in U.S.
Dollars, calculated at the BMS's customary internal corporate monthly exchange
rates for the last month of the calendar quarter for which remittance is made
for royalties. Such payments shall be free of any taxes, charges, or remittance
fees, except for income tax levied upon or required to be withheld and paid by
BMS, its Affiliates or its Sub-sublicensees for the account of PROGENICS. BMS
shall provide PROGENICS appropriate receipts of payment of such withholding
taxes or other proof thereof. For each month and each currency, BMS's customary
internal corporate monthly exchange rate shall equal the arithmetic average of
the daily exchange rates (obtained as described below) during the period from
(i) the 20th day of the preceding month (or, if such 20th day is not a business
day, the immediately preceding business day) through (ii) the 19th day of the
current month (or, if such 19th day is not a business day, the immediately
preceding business day); each daily exchange rate shall be obtained from the
Reuters Daily Rate Report or The Wall Street Journal, Eastern U.S. Edition, or,
if not so available, as furnished by BMS's local Affiliates.

      6.4 Records Retention. BMS and its Affiliates and Sub-sublicensees shall
keep accurate records of all operations affecting payments hereunder, shall
maintain such records for a period of three years and shall permit PROGENICS or
its duly authorized agent to inspect all such records and to make copies of or
extracts from such records during regular business hours throughout the term of
this Agreement and for a reasonable period of three years thereafter.

      6.5 Audit Request. At the request and expense of PROGENICS, BMS and its
Affiliates and Sub-sublicensees shall permit PROGENICS or an independent,
certified public accountant appointed by PROGENICS and reasonably acceptable to
BMS, at reasonable times and upon reasonable notice, to examine those records as
may be necessary to: (i) determine the correctness of any report or payment made
under this Agreement; or (ii) obtain information as to Net Sales and the
royalties payable for any calendar quarter. If an accountant is used, said
accountant shall not disclose to PROGENICS any information other than
information relating to said reports, royalties, and payments. Results of any
such examination shall be made available to both Parties.

      6.6 Cost of Audit; Discrepancies. PROGENICS shall bear the full cost of
the performance of any such audit except as hereinafter set forth. If, as a
result of any inspection of the books and records of BMS, its Affiliates or its
Sub-sublicensees, it is shown that BMS's payments under this Agreement were less
than the amount which should have been paid, then BMS shall make all payments
required to be made to eliminate any discrepancy revealed by said inspection
within 30 days after PROGENICS's demand therefor, plus interest at the prime
rate from the date payment should have been made. Furthermore, if the payments
were less than the amount which


                                      -14-
<PAGE>

should have been paid by an amount in excess of five percent of the payments
actually made during the period in question, BMS shall also reimburse PROGENICS
for the costs of such audit in addition to the payment required to be made to
eliminate any discrepancy.

      6.7 No Non-Monetary Consideration for Sales. Without the prior written
consent of PROGENICS, BMS and its Affiliates and Sub-sublicensees shall not
accept or solicit any non-monetary consideration in the sale of Aquila Licensed
Products other than as would be reflected in Net Sales. The use by BMS and its
Affiliates and Sub-sublicensees of commercially reasonable amounts of Aquila
Licensed Products for clinical trials and promotional sampling shall not violate
this provision.

7. MANUFACTURE AND SUPPLY.

      7.1 Retained Right of Aquila. BMS agrees that Aquila retains the right to
Manufacture the Adjuvant for use in Aquila Licensed Products.

8. PATENTS PROSECUTION; ENFORCEMENT.

      8.1 Patent Prosecution. BMS acknowledges and agrees that the Aquila
Licensed Patent Rights will continue to be prosecuted (in the case of patent
applications) and maintained (in the case of patents) by Aquila or PROGENICS.
PROGENICS agrees that the Aquila Licensed Patent Rights shall be prosecuted
and/or maintained in accordance with the Aquila/PROGENICS License and Supply
Agreement and, to the extent permitted thereunder, with diligence the same as or
greater than is used for PROGENICS' own patents and patent applications. To the
extent that PROGENICS has the right to do so, PROGENICS shall not permit any
Aquila Licensed Patent Rights to be abandoned.

      8.2 Patent Costs. All out-of-pocket costs and expenses incurred by
PROGENICS under the Aquila/PROGENICS License and Supply Agreement in connection
with the prosecution and maintenance of the Aquila Licensed Patent Rights shall
be the sole responsibility of PROGENICS.

      8.3 Patent Enforcement.

            (a) Each Party shall inform the other Party promptly in writing of
any alleged infringement of any Aquila Licensed Patent Rights by a Third Party
of which it shall have knowledge and provide any available evidence of
infringement.

            (b) BMS acknowledges and agrees that, under the Aquila/PROGENICS
License and Supply Agreement, Aquila and PROGENICS shall consult as to potential
litigation strategies against any


                                      -15-
<PAGE>

alleged infringer, and PROGENICS simultaneously shall consult with BMS as to
same.

            (c) BMS acknowledges and agrees that, if Aquila and PROGENICS do not
jointly commence an action within 30 days after notice of alleged infringement
of the Aquila Licensed Patent Rights, Aquila shall have the right to bring suit
against the allegedly infringing party, at its sole expense. Aquila and/or
PROGENICS shall be entitled to recovery of damages resulting from any lawsuit
brought by Aquila and PROGENICS jointly or Aquila alone, as the case may be,
pursuant to the Aquila/PROGENICS License and Supply Agreement.

9. TERM; TERMINATION.

      9.1 Term. This Agreement shall commence as of the Effective Date and,
unless sooner terminated as provided in this Section 9, shall expire on the date
royalties are no longer payable by PROGENICS to Aquila under Section 3.3 of the
Aquila/PROGENICS License and Supply Agreement (the "Term"), upon which
expiration BMS shall thereafter have in perpetuity a royalty-free license
hereunder in the Aquila Licensed Territory to use the Aquila Knowhow, and
practice the Aquila Licensed Patent Rights to develop, make, have made, use and
sell Aquila Licensed Products without any accounting to PROGENICS.

      9.2 Material Breach. Subject to Section 11.5, failure by either Party to
comply with any of the material obligations contained in this Agreement shall
entitle the other Party to give to the Party in default notice specifying the
nature of the default and requiring it to cure such default. If such default is
not cured within 60 days after the receipt of such notice (or, if such default
cannot reasonably be cured within such 60-day period, if the defaulting party
has not promptly commenced and diligently pursued cure of such default during
such 60-day period), the notifying Party shall be entitled, without prejudice to
any of its other rights conferred on it by this Agreement and in addition to any
other remedies available to it by law or in equity, to terminate this Agreement
effective upon written notice to the other Party. The right of a Party to
terminate this Agreement, as hereinabove provided, shall not be affected in any
way by its waiver or failure to take action with respect to any previous
default.

      9.3 Effect of Termination. Upon termination of this Agreement in its
entirety for any reason other than expiration of this Agreement pursuant to
Section 9.1, BMS shall promptly: (1) return to PROGENICS, at BMS's expense, all
relevant data and other information concerning the Aquila Licensed Patent Rights
in the possession or control of BMS, its Affiliates and Sub-sublicensees; (2)
transfer, at BMS's expense, to PROGENICS or such other Person, as PROGENICS
shall designate, any and all rights that it may have


                                      -16-
<PAGE>

under any government registrations or authorizations in any country in the
Territory with respect to the Aquila Licensed Products; (3) cancel any
government registrations or authorizations with respect to the Aquila Licensed
Products as may not be transferable; (4) provide to PROGENICS, at BMS's expense,
all data and other information in BMS's, or its Affiliates' or
Sub-sublicensees', possession or control relating to such governmental
registrations or authorities in any country in the Territory with respect to all
Aquila Licensed Products; and (5) discontinue all manufacture, use, sale and
distribution of all Aquila Licensed Products and the use of the Aquila Licensed
Patent Rights in connection therewith. All rights granted to BMS under this
Agreement shall revert to PROGENICS.

      9.4 Right to Sell Stock on Hand. If BMS is not in material breach of this
Agreement at the time of termination of this Agreement, then BMS shall have the
right for one year thereafter to dispose of all Aquila Licensed Products then in
its inventory, and shall pay royalties thereon, in accordance with the
provisions of this Agreement, as though this Agreement had not terminated.

      9.5 Termination of Sublicenses. Upon any termination of this Agreement,
all sublicenses granted by BMS under this Agreement shall terminate
simultaneously, subject, nevertheless, to Section 9.4.

      9.6 Accrued Rights; Surviving Obligations. Expiration or any termination
of this Agreement for any reason shall be without prejudice to any rights which
shall have accrued to the benefit of either Party prior to such expiration or
termination. Such expiration or termination shall not relieve either Party from
obligations which are expressly indicated to survive expiration or termination
of this Agreement, which obligations include, without limitation, those under
Sections 1, 6, 8.3 (solely with respect to actions in existence at the time of
termination), 9.3, 9.4, 10, 11.4, 11.9 and 11.12.

10. ARBITRATION.

      10.1 Arbitration. Any dispute, controversy or claim between the Parties,
arising out of or relating to this Agreement or the Parties' respective rights
and obligations hereunder either during or after the Term (including the
question as to whether any such matter is arbitrable shall be subject to binding
arbitration in accordance with then-existing commercial arbitration rules of the
American Arbitration Association. The Parties agree that, in the course of any
such arbitration, service of any notice at their respective addresses in
accordance with Section 11.10 of this Agreement shall be valid and sufficient,
and any arbitration hereunder shall be in New York, New York, unless Aquila is a
defendant in such arbitration pursuant to Section 12 of the


                                      -17-
<PAGE>

Aquila/PROGENICS License and Supply Agreement, in which event such arbitration
shall be held in Massachusetts. In any such arbitration, an award shall be
rendered by a majority of the members of a board of arbitration consisting of
three members, one of whom shall be chosen by each of Progenics and BMS and the
third of whom shall be appointed by mutual agreement of such two arbitrators. In
the event of failure of such two arbitrators to agree within 60 days after the
commencement of arbitration (as defined below) upon appointment of the third
arbitrator, or in the event that either Party shall fail to appoint an
arbitrator within 30 days after the commencement of the arbitration proceedings,
the third arbitrator or (upon request of the other Party) the second arbitrator
and the third arbitrator, as the case may be, shall be appointed by the American
Arbitration Association in accordance with its then existing commercial
arbitration rules. For purposes of this Section 10.1, the "commencement of the
arbitration proceeding" shall mean the date upon which the defendant Party
receives from the American Arbitration Association a copy of the request for
arbitration filed by the party desiring to have recourse to arbitration. The
decision of the arbitrators shall be in writing and shall set forth the basis
therefor. The Parties shall abide by all awards rendered in arbitration
proceedings, and such awards may be enforced and executed upon in any court
having jurisdiction over the Party against whom enforcement of such award is to
be sought. The Parties shall divide equally the administrative charges,
arbitrators' fees, and related expenses of arbitration, but each Party shall pay
its own legal fees incurred in connection with any such arbitration; provided,
however, if the arbitrators determine that the Party prevailed clearly and
substantially over the other Party, then the non-prevailing party shall also pay
the reasonable attorneys' fees and expert witness costs and other arbitration
costs of the prevailing Party.

11. MISCELLANEOUS PROVISIONS.

      11.1 No Partnership. Nothing in this Agreement is intended or shall be
deemed to constitute a partnership, distributorship, agency, employer-employee
or joint venture relationship between the Parties. No Party shall incur any
debts or make any commitments for the other, except to the extent, if at all,
specifically provided herein.

      11.2 Assignments. Neither Party shall assign any of its right or
obligations hereunder or this Agreement, except that either Party may do so: (a)
as incident to the merger, consolidation, reorganization or acquisition of stock
or assets affecting substantially all of the assets or voting control of such
Party; (b) to any wholly-owned subsidiary if such Party remains liable and
responsible for the performance and observance of all of the subsidiary's duties
and obligations hereunder; or (c) with the prior written consent of the other
Party. This Agreement shall be binding


                                      -18-
<PAGE>

upon the successors and permitted assigns of the Parties and the name of a Party
appearing herein shall be deemed to include the names of such Party's successors
and permitted assigns of the extent necessary to carry out the intent of this
Agreement. Any assignment not in accordance with this Section 11.2 shall be
void.

      11.3 Further Actions. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all such other acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

      11.4 No Name or Trademark Rights. Except as otherwise provided herein, no
right, express or implied, is granted to BMS by this Agreement to use in any
manner the name "Aquila Biopharmaceuticals, Inc." or any contraction thereof or
any other trade name or trademark of Aquila in connection with the performance
of this Agreement.

      11.5 Force Majeure. Neither Party shall be liable to the other for loss or
damages or shall have any right to terminate this Agreement for any default or
delay attributable to any act of God, flood, fire, explosion, strike, lockout,
labor dispute, shortage of raw materials, casualty or accident, war, revolution,
civil commotion, act of public enemies, blockage or embargo, injunction, law,
order, proclamation, regulation, ordinance, demand or requirement of any
government or subdivision, authority or representative of any such government,
or any other cause beyond the reasonable control of such Party, if the Party
affected shall give prompt notice of any such cause to the other Party. The
Party giving such notice shall thereupon be excused from such of its obligations
hereunder as it is thereby disabled from performing for so long as it is so
disabled and for 30 days thereafter. Notwithstanding the foregoing, nothing in
this Section 11.5 shall excuse or suspend the obligation to make any payment due
hereunder in the manner and at the time provided.

      11.6 Severability. In the event that any of the provisions of this
Agreement shall for any reason be held by any court or authority of competent
jurisdiction to be invalid, illegal or unenforceable, such provision or
provisions shall be validly reformed to as nearly as possible approximate the
intent of the Parties and, if unreformable, shall be divisible and deleted in
such jurisdiction; elsewhere, this Agreement shall not be affected so long as
the Parties are still able to realize the principal benefits bargained for in
this Agreement.

      11.7 Amendments. No waiver, modification or amendment of any provision of
this Agreement shall be valid or effective unless made in writing and signed by
a duly authorized officer of each of the Parties.


                                      -19-
<PAGE>

      11.8 Captions. The captions to this Agreement are for convenience only,
and are to be of no force or effect in construing or interpreting any of the
provisions of this Agreement.

      11.9 Applicable Law. This Agreement shall be governed by and interpreted
in accordance with the laws of the Commonwealth of Massachusetts applicable to
agreements made and performed wholly within such state without regard to its
principles of conflicts of laws.

      11.10 Notices and Deliveries. Any notice, requests, delivery, approval or
consent required or permitted to be given under this Agreement shall be in
writing and shall be deemed to have been sufficiently given if delivered in
person, transmitted by telecopy (with written confirmation to follow via United
States first class mail) or five days after being sent by United States
certified mail to the Party to whom it is directed at its address shown below or
such other address as such Party shall have last given by written notice to the
other Party in accordance with this Section 11.10.

            (a) If to PROGENICS, addressed to:

                    Progenics Pharmaceuticals, Inc.
                    777 Old Saw Mill River Road
                    Tarrytown, NY 10591
                    Attention: Dr. Paul Maddon
                    Telecopy: 914-789-2817

            (b) If to BMS, addressed to:

                    Bristol-Myers Squibb Company
                    P.O. Box 4000
                    Route 206 & Province Line Road
                    Princeton, New Jersey 08543-4000
                    Attention:  Vice President and Senior
                    Counsel, Pharmaceutical Research
                    Institute, and Worldwide Franchise
                    Management and Strategic Business
                    Development
                    Telecopy: (609) 252-4232


                                      -20-
<PAGE>

            (c) If to Aquila, addressed to:

                    Aquila Biopharmaceuticals, Inc.
                    365 Plantation Street
                    Worcester, MA 01605
                    Attention: President
                    Telecopy: 508-797-4014
                    
                    with a copy to:
                    
                    Attention: General Counsel
                    Telecopy: 508-797-4014

      11.11 Counterparts. This Agreement may be executed simultaneously 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.

      11.12 Compliance with Laws. PROGENICS and BMS each shall comply with all
applicable laws in connection with its own performance under this Agreement.
Without limiting the generality of the foregoing, BMS shall be responsible for
compliance with all applicable product safety, product testing, product
labeling, package marking, and product advertising laws and regulations.

      IN WITNESS WHEREOF, the Parties hereto have caused this Sublicense
Agreement to be signed by their respective corporate officers, duly authorized
as of the day and year first above written.

                                        PROGENICS PHARMACEUTICALS, INC.
                                        
                                        
                                        By: /s/ Paul J. Maddon
                                           -------------------------------------
                                        Name:  Paul J. Maddon, M.D., Ph.D.
                                        Title: Chairman and Chief 
                                                 Executive Officer
                                        
                                        
                                        BRISTOL-MYERS SQUIBB COMPANY
                                        

                                        By: /s/ Charles Linzner
                                           -------------------------------------
                                        Name:  Charles Linzner
                                        Title: Vice President


                                      -21-
<PAGE>

                                   EXHIBIT A

                         AQUILA LICENSED PATENT RIGHTS

Application or Patent Number              Filing or Issue Date
- ----------------------------              --------------------

U.S. Patent No. 5,057,540, 
  entitled "Saponin Adjuvant" 
  inventors Charlotte A. Kensil 
  and Dante J. Marciani                   October 15, 1991

           [XXX]                                [XXX]

Canadian Patent No. 1,331,443             August 16, 1994

European Patent No. 362,279               January 11, 1995

German Patent No. 3,852,761               February 23, 1995


<PAGE>

                                                               Exhibit 10.27

[Note: Certain portions of this document have been marked "[XXX]" to 
indicate that confidentiality has been requested for this information. The 
confidential portions have been omitted and filed separately with the 
Securities and Exchange Commission.]

As of April 15, 1997

Sloan-Kettering Institute for Cancer Research
1275 York Avenue
New York, New York 10021
Attention:  Mr. James S. Quirk

      RE: Progenics Pharmaceuticals, Inc.

Dear Mr. Quirk:

      As you may know, Progenics Pharmaceuticals, Inc. ("Progenics") and
Bristol-Myers Squibb Company ("BMS") have entered into a sublicense agreement
(the "Progenics/BMS Sublicense Agreement") whereby Progenics has sublicensed BMS
under certain patent and technology rights relating to the treatment of human
cancers for which Progenics has acquired a license from you pursuant to that
license agreement dated November 17, 1994 between Progenics and you (the "Sloan-
Kettering/Progenics License Agreement"). A copy of the Progenics/BMS Sublicense
Agreement is enclosed.

      To facilitate the creation of the relationship between BMS and Progenics
and to provide for certain terms of the relationship among BMS, Progenics and
you, we ask that you agree with us to the following:

      1.    Sublicense.

            (a) We believe that the Progenics/BMS Sublicense Agreement meets the
requirements of Section 6.02 of the Sloan-Kettering/Progenics License Agreement,
to the extent relevant and appropriate. Further, in compliance with Section 6.02
of the Sloan-Kettering/Progenics License Agreement, BMS acknowledges and agrees
that Sloan-Kettering shall be a third party beneficiary under the Progenics/BMS
Sublicense Agreement with respect to BMS's obligations under such relevant
Sections.

            (b) All upfront fees and royalty payments to be made by BMS to
Progenics pursuant to Section 4 of the Progenics/BMS Sublicense Agreement shall
be paid by Progenics to Sloan-Kettering in satisfaction of Progenics's royalty
obligation to Sloan-Kettering under the Sloan-Kettering/Progenics License
Agreement with respect to Sublicense Royalties due on Sublicense Income (as such
terms are defined in the Sloan-Kettering/Progenics License Agreement) received
by Progenics from BMS thereunder.

      2. Representations and Warranties. Sloan-Kettering represents and warrants
that: (a) the Sloan-Kettering/Progenics License Agreement is in full force and
effect and has not been modified or amended; and (b) to the best of
Sloan-Kettering's knowledge, neither Sloan-Kettering nor Progenics is in default
under, and neither party claims or has grounds upon which to claim the other
party is in default under, the Sloan-Kettering/Progenics License Agreement.

      3. Termination of Sloan-Kettering/Progenics License Agreement by Sloan-
Kettering.

            (a) In the event that Sloan-Kettering seeks to terminate the Sloan-
Kettering/Progenics License Agreement due to a default by Progenics, Sloan-
Kettering shall provide to BMS a simultaneous copy of any notice of termination
given to Progenics.

            (b) Upon receipt of any such notice from Sloan-Kettering by BMS, BMS
shall have 45 days to determine whether to cure such default. In the event that
Sloan-Kettering receives written notice from BMS during such 45-day period that
BMS agrees to cure such default, Sloan-Kettering shall succeed to all of the
rights and obligations of Progenics under the Progenics/BMS Sublicense Agreement
as if Sloan-Kettering was a party thereto in lieu of Progenics. Commencing on
the date of BMS's notice to Sloan-
<PAGE>

Sloan-Kettering Institute for Cancer Research
As of April 15, 1997
Page 2

Kettering, BMS shall have an additional 30 days within which to cure the prior
default by Progenics. This shall be in lieu of BMS's rights as a sublicensee set
forth in Section 6.03 of the Sloan-Kettering/Progenics License Agreement.

      4.    Amendments and Waivers by Sloan-Kettering.

            (a) Sloan-Kettering and Progenics hereby agree to amend the
milestones set forth in Sections 5.01(c) and (d) of the Sloan-
Kettering/Progenics License Agreement to read in their entirety as follows:

                  "c) [XXX].
     
                   d) [XXX]."

            (b) Sloan-Kettering and Progenics hereby agree to amend Section 5.01
of the Sloan-Kettering/Progenics License Agreement to add the following
provision:

            "The parties acknowledge and agree that the milestones contained in
      this Section 5.01 were established on the assumption that the milestones
      would apply to development of that certain LICENSED PRODUCT composed of
      GM2 conjugated to KLH and combined with QS-21 (the "GMK Vaccine"). In the
      event that development of the GMK Vaccine is terminated due to safety or
      efficacy reasons, the parties agree that the milestones set forth in this
      Section 5.01 shall not apply and the parties will negotiate in good faith
      to establish new milestones."

            (c) Sloan-Kettering hereby waives Section 14.01 of the 
Sloan-Kettering/Progenics License Agreement with respect to BMS, such that 
the Progenics/BMS Sublicense Agreement shall not be required to contain a 
comparable provision. Instead, BMS agrees that it will not hire as board 
members or employees any of [XXX] without first obtaining Sloan-Kettering's 
prior written consent.

            (d) Sloan-Kettering and Progenics hereby agree to amend the notice
provision set forth in Article XIX of the Sloan-Kettering/Progenics License
Agreement so that all notices to LICENSEE thereunder shall be copied to BMS at
the following address:

                  Bristol-Myers Squibb Company
                  P.O. Box 4000
                  Route 206 & Province Line Road
                  Princeton, New Jersey 08543-4000
                  Attention:  Vice President and Senior Counsel,
                        Pharmaceutical Research Institute,
                        and Worldwide Franchise Management 
                        and Strategic Business Development

or to such other address of which BMS shall notify the other parties in writing.

      5. Indemnification. BMS will indemnify and hold Sloan-Kettering harmless
against any and all actions, suits, claims, demands, prosecutions, costs and
expenses (including actual reasonable attorneys' fees) based on or arising out
of the Progenics/BMS Sublicense Agreement, including, without limitation, the
manufacture, packaging, use, sale, rental or lease of S-K Products, even if
altered or used for a purpose not intended, or the use of S-K Licensed Patents
or S-K Licensed Technical Information by BMS, its Affiliates, its Sublicensees
or its (or their) customers and any
<PAGE>

Sloan-Kettering Institute for Cancer Research
As of April 15, 1997
Page 3

representation made or warranty given by BMS, its Affiliates or Sublicensees
with respect to S-K Products or S-K Licensed Technology. Capitalized terms used
in this Section and not defined in this Agreement shall have the meanings
ascribed to them in the Progenics/BMS Sublicense Agreement.

      If the terms set forth in this letter are acceptable to you, please sign
the two enclosed copies of this letter and return them in the envelope provided.


Sincerely yours,


PROGENICS PHARMACEUTICALS, INC.           BRISTOL-MYERS SQUIBB COMPANY


By: /s/ Paul J. Maddon                    By: /s/ Charles Linzner
    ------------------------------            ------------------------------
Name:  Paul J. Maddon, M.D., Ph.D.        Name:     Charles Linzner
Title: Chairman and Chief                 Title:    Vice President
         Executive Officer



AGREED TO AND ACCEPTED ON
5/28, 1997:

SLOAN-KETTERING INSTITUTE
     FOR CANCER RESEARCH


By: /s/ James S. Quirk
    ------------------------------
Name:     James S. Quirk
Title:    Senior Vice President
          Research Resources Management


<PAGE>

                                                                Exhibit 10.28


As of April 15, 1997


The Regents of the University of California
Business Research Partnerships
Box 951525, 1106 Ueberroth Building
University of California, Los Angeles
Los Angeles, California 90095-1525
Attention: Ms. Fredrica S. Reiter

     RE:  Progenics Pharmaceuticals, Inc.
          -------------------------------

Dear Ms. Reiter:

     As you may know, Progenics Pharmaceuticals, Inc. ("Progenics") and 
Bristol-Myers Squibb Company ("BMS") have entered into a sublicense 
agreement (the "Progenics/BMS Agreement") whereby Progenics has sublicensed 
BMS under the patent right for which Progenics has acquired a license from 
you pursuant to that license agreement dated June 25, 1996 between Progenics 
and you ("The Regents/Progenics License Agreement"). A copy of the 
Progenics/BMS Sublicense Agreement is enclosed.

     To facilitate the creation of the relationship between BMS and Progenics 
and to provide for certain terms of the relationship among BMS, Progenics and 
you, we ask that you agree with us to the following:

     1.  Sublicense.

         (a)  The Regents acknowledges receipt of a copy of the Progenics/BMS 
Sublicense Agreement.

         (b)  All upfront fees, milestone payments and royalty payments to be 
made by BMS to Progenics pursuant to Section 4 of the Progenics/BMS 
Sublicense Agreement shall be paid by Progenics to The Regents in 
satisfaction of Progenics's obligation to The Regents under The 
Regents/Progenics License Agreement with respect to Sublicensing Income (as 
such term is defined in The Regents/Progenics License Agreement) received by 
Progenics from BMS thereunder.

         (c)  Pursuant to Section 9.3 of The Regents/Progenics License 
Agreement, Progenics hereby notifies The Regents that BMS, a Sublicensee of 
Progenics, is not a small entity (as such term is defined by the United 
States Patent and Trademark Office) under the provisions of 35 U.S.C. Section 
41(h).

     2.  Representations and Warranties. The Regents represents and warrants 
that: (a) The Regents/Progenics License Agreement is in full force and effect 
and has not been modified or amended; and (b) to the best of The Regents' 
knowledge, neither The Regents nor Progenics is in default under, and neither 
party claims or has grounds upon which to claim the other party is in 
default under, The Regents/Progenics License Agreement.

     3.  Termination of The Regents/Progenics License Agreement by The 
Regents. In furtherance of the provision contained in Section 3.4 of The 
Regents/Progenics License Agreement:

         (a)  In the event that The Regents seeks to terminate The 
Regents/Progenics License Agreement pursuant to Section 6.4 or 12.1 thereof 
due to a default by Progenics, The Regents shall provide to BMS a 
simultaneous copy of any notice of termination given to Progenics.

         (b)  Upon receipt of any such notice from The Regents by BMS, BMS 
shall have 45 days to determine whether to cure such default. In the



<PAGE>

The Regents of the University of California
As of April 15, 1997
Page 2

event that The Regents receives written notice from BMS during such 45-day 
period that BMS agrees to cure such default, then Progenics shall assign the 
Progenics/BMS Sublicense Agreement to The Regents, who shall succeed to all 
of the rights and obligations of Progenics under the Progenics/BMS Sublicense 
Agreement as if The Regents was a party thereto in lieu of Progenics, except 
that the duties of The Regents under the Progenics/BMS Sublicense Agreement 
will not be greater than the duties of The Regents under The 
Regents/Progenics License Agreement, and the rights of The Regents under the 
Progenics/BMS Sublicense Agreement will not be less than the rights of The 
Regents under The Regents/Progenics License Agreement. Commencing on the date 
of BMS's notice to The Regents, BMS shall have an additional 30 days within 
which to cure the prior default by Progenics. This shall be in lieu of 
Section 3.4 of The Regents/Progenics License Agreement.

     4.  Amendments and Waivers by The Regents.

         (a)  The Regents and PROGENICS hereby agree to amend Section 6.3 of 
The Regents/PROGENICS License Agreement to add the following provision:

         "The parties acknowledge and agree that the milestones contained in 
     this Section 6.3 were established on the assumption that the milestones 
     would apply to development of that certain Licensed Product composed of 
     GM2 conjugated to KLH and combined with QS-21 (the "GMK Vaccine"). In 
     the event that development of the GMK Vaccine is terminated due to safety
     or efficacy reasons, the parties agree that the milestones set forth in 
     this Section 6.3 shall not apply and the parties will negotiate in good 
     faith to establish new milestones."

         (b)  The Regents hereby agrees to waive the requirements of Sections 
9.2(b), (e) and (f) of The Regents/Progenics License Agreement with respect 
to reports from Progenics that pertain to work being performed by or with BMS.

         (c)  The Regents and Progenics hereby agree to amend Section 10.1 of 
The Regents/Progenics License Agreement to provide that books and records 
need only be retained for three years from the date of the royalty payment to 
which they pertain, rather than five years.

         (d)  The Regents and Progenics hereby agree to amend Section 14.1 of 
The Regents/Progenics License Agreement to provide that Progenics will have 
the right to dispose of Licensed Products for a period of one year, rather 
than six months.

         (e)  The Regents and Progenics hereby agree to amend the notice 
provision set forth in Section 19 of The Regents/Progenics License Agreement 
so that all notices to Licensee thereunder shall be copied to BMS at the 
following address:

              Bristol-Myers Squibb Company
              P.O. Box 4000
              Route 206 & Province Line Road
              Princeton, New Jersey 08543-4000
              Attention:  Vice President and Senior Counsel,
                    Pharmaceutical Research Institute,
                    and Worldwide Franchise Management
                    and Strategic Business Development


<PAGE>

The Regents of the University of California
As of April 15, 1997
Page 3

or to such other address of which BMS shall notify the other parties in 
writing.

     5.  Indemnification. BMS must indemnify, hold harmless and defend The 
Regents, its officers, employees, and agents, the inventors of the patents 
and patent applications in Regents' Patent Rights and their respective 
employers from and against any and all liability, claims, suites, losses, 
damages, costs, fees and expenses resulting from or arising out of exercise 
of the Progenics/BMS Sublicense Agreement. Capitalized terms used in this 
Section and not defined in this Agreement shall have the meanings ascribed to 
them in the Progenics/BMS Sublicense Agreement.

     If the terms set forth in this letter are acceptable to you, please sign 
the two enclosed copies of this letter and return them in the envelope 
provided.


Sincerely yours,


PROGENICS PHARMACEUTICALS, INC.             BRISTOL-MYERS SQUIBB COMPANY


By: /s/Paul J. Maddon                       By: /s/Charles Linzner
    ------------------------------              ------------------------
Name:  Paul J. Maddon, M.D., Ph.D.          Name:  Charles Linzner
Title: Chairman and Chief                         ----------------------
        Executive Officer
                                            Title: Vice President
                                                  ----------------------



AGREED TO AND ACCEPTED ON
June 9, 1997:
- ------

THE REGENTS OF THE UNIVERSITY
    OF CALIFORNIA


By: /s/Fredrica A. Reiter
    ---------------------
Name: Fredrica A. Reiter
      -------------------
Title: Technology Transfer Officer
       ---------------------------


<PAGE>

[Note: Certain portions of this document have been marked "[XXX]" to 
indicate that confidentiality has been requested for this information. The 
confidential portions have been omitted and filed separately with the 
Securities and Exchange Commission.]

                                                                   Exhibit 10.29

As of April 15, 1997


Aquila Biopharmaceuticals, Inc.
365 Plantation Street
Worcester, Massachusetts 01605
Attention:  Dr. Alison Taunton-Rigby

      RE: Progenics Pharmaceuticals, Inc.

Dear Dr. Taunton-Rigby:

      As you may know, Progenics Pharmaceuticals, Inc. ("Progenics") and
Bristol-Myers Squibb Company ("BMS") have entered into a sublicense agreement
(the "Progenics/BMS Sublicense Agreement") whereby Progenics has sublicensed BMS
under certain patent and technology rights relating to the adjuvant (the
"Adjuvant") derived from the tree Quillaja saponaria for which Progenics has
acquired a license from you pursuant to that license and supply agreement dated
August 31, 1995 between Progenics and Cambridge Biotech Corporation, the name
under which Aquila was formerly known (the "Aquila/Progenics License and Supply
Agreement"). A copy of the Progenics/BMS Sublicense Agreement is enclosed.

      To facilitate the creation of the relationship between BMS and Progenics
and to provide for certain terms of the relationship among BMS, Progenics and
you, we ask that you agree with us to the following:

      1.    Sublicense.

            (a) Aquila acknowledges receipt of a copy of the Progenics/BMS
Sublicense Agreement.

            (b) All upfront fees and royalty payments to be made by BMS to
Progenics pursuant to Section 4 of the Progenics/BMS Sublicense Agreement shall
be paid by Progenics to Aquila in satisfaction of Progenics's obligation to
Aquila under the Aquila/Progenics License and Supply Agreement with respect to
the Sublicense (as such term is defined in the Aquila/Progenics License and
Supply Agreement) granted to BMS by Progenics under the Progenics/BMS Sublicense
Agreement.

      2. Representations and Warranties. Aquila represents and warrants that:
(a) the Aquila/Progenics License and Supply Agreement is in full force and
effect and has not been modified or amended; and (b) to the best of Aquila's
knowledge, neither Aquila nor Progenics is in default under, and neither party
claims or has grounds upon which to claim the other party is in default under,
the Aquila/Progenics License and Supply Agreement.

      3. Termination of the Aquila/Progenics License and Supply Agreement by
Aquila.

            (a) In the event that Aquila seeks to terminate the Aquila/Progenics
License and Supply Agreement pursuant to Section 5.1 or 10.2 thereof due to a
default by Progenics, Aquila shall provide to BMS a simultaneous copy of any
notice of termination given to Progenics.

            (b) Upon receipt of any such notice from Aquila by BMS, BMS shall
have 45 days to determine whether to cure such default. In the event that Aquila
receives written notice from BMS during such 45-day period that BMS agrees to
cure such default, Aquila shall succeed to all of the rights and obligations of
Progenics under the Progenics/BMS
<PAGE>

Aquila Biopharmaceuticals, Inc.
As of April 15, 1997
Page 2

Sublicense Agreement as if Aquila was a party thereto in lieu of Progenics.
Commencing on the date of BMS's notice to Aquila, BMS shall have an additional
30 days within which to cure the prior default by Progenics. This shall be in
lieu of BMS's rights as a sublicensee of Progenics to seek a license from Aquila
pursuant to Section 10.3 of the Aquila/Progenics License and Supply Agreement.

      4.    Amendments and Waivers by Aquila.

            (a) Aquila and Progenics hereby agree to amend the first sentence of
Section 4.2(a) of the Aquila/Progenics License and Supply Agreement to provide
that royalty payments will be made within sixty (60) days after the end of each
calendar quarter, rather than thirty (30) days with respect to payments due from
Progenics as a result of the Progenics/BMS Sublicense Agreement.

            (b) Aquila and Progenics hereby agree to amend the milestones set
forth in Sections 5.01(c) and (d) of the Aquila/Progenics License and Supply
Agreement to read in their entirety as follows:

                 "(c) [XXX];

                  (d) [XXX]"

            (c) Aquila and Progenics hereby agree to amend Section 5.1 of the
Aquila/Progenics License and Supply Agreement to add the following provision:

            "The parties acknowledge and agree that the milestones contained in
      this Section 5.1 were established on the assumption that the milestones
      would apply to development of that certain Licensed Product composed of
      GM2 conjugated to KLH and combined with QS-21 (the "GMK Vaccine"). In the
      event that development of the GMK Vaccine is terminated due to safety or
      efficacy reasons, the parties agree that the milestones set forth in this
      Section 5.1 shall not apply and the parties will negotiate in good faith
      to establish new milestones."

            (d) Aquila and Progenics hereby agree to amend the second sentence
of Section 10.2 of the Aquila/Progenics License and Supply Agreement to read in
its entirety as follows:

            "If such default is not cured within sixty (60) days after the
      receipt of such notice (or, if such default cannot reasonably be cured
      within such 60-day period, if the defaulting party has not promptly
      commenced and diligently pursued cure of such default during such 60-day
      period), the notifying party shall be entitled, without prejudice to any
      of its other rights conferred on it by the Agreement and in addition to
      any other remedies available to it by law or in equity, to terminate this
      Agreement effective upon written notice to the other Party."
<PAGE>

Aquila Biopharmaceuticals, Inc.
As of April 15, 1997
Page 3

            (e) Aquila and Progenics hereby agree to amend Section 13.11 of the
Aquila/Progenics License and Supply Agreement so that all notices to Progenics
thereunder shall be copied to BMS at the following address:

                  Bristol-Myers Squibb Company
                  P.O. Box 4000
                  Route 206 & Province Line Road
                  Princeton, New Jersey 08543-4000
                  Attention:  Vice President and Senior Counsel,
                        Pharmaceutical Research Institute,
                        and Worldwide Franchise Management
                        and Strategic Business Development

or to such other address of which BMS shall notify the other parties in writing.

      If the terms set forth in this letter are acceptable to you, please sign
the two enclosed copies of this letter and return them in the envelope provided.


Sincerely yours,


PROGENICS PHARMACEUTICALS, INC.           BRISTOL-MYERS SQUIBB COMPANY


By: /s/ Paul J. Maddon                    By: /s/ Charles Linzner
    ------------------------------            ------------------------------
Name:  Paul J. Maddon, M.D., Ph.D.        Name:  Charles Linzner
Title: Chairman and Chief                 Title: Vice President
       Executive Officer



AGREED TO AND ACCEPTED ON
6/10/97, 1997:

AQUILA BIOPHARMACEUTICALS, INC.


By: /s/ Alison Taunton-Rigby
    ------------------------------
Name:  Alison Taunton-Rigby
Title: President & CEO


<PAGE>

                                                                   Exhibit 10:30

THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933.  THIS WARRANT HAS BEEN ACQUIRED FOR
INVESTMENT AND NOT WITH A VIEW TO THE DISTRIBUTION HEREOF OR OF THE SECURITIES
ISSUABLE UPON EXERCISE HEREOF WITHIN THE MEANING OF THE SECURITIES ACT OF 1933
AND THE RULES AND REGULATIONS THEREUNDER.  NEITHER THIS WARRANT NOR THE
SECURITIES ISSUABLE UPON EXERCISE HEREOF MAY BE TRANSFERRED IN THE ABSENCE OF AN
EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE SECURITIES ACT OF
1933 OR UPON RECEIPT BY THE COMPANY OF AN OPINION SATISFACTORY TO THE COMPANY OF
COUNSEL TO THE PROPOSED TRANSFEREE OR THE COMPANY AS TO AN EXEMPTION THEREFROM. 
THIS WARRANT IS ALSO SUBJECT TO CERTAIN RIGHTS OF FIRST REFUSAL AND REPURCHASE
SET FORTH IN A SUBSCRIPTION AGREEMENT, A COPY OF WHICH IS AVAILABLE FOR
INSPECTION AT THE PRINCIPAL OFFICE OF THE COMPANY.

                        Warrant Number: 
                        Warrant to Subscribe for _______ Shares of Stock


                                STOCK PURCHASE WARRANT

                        To Subscribe for and Purchase Stock of

                           PROGENICS PHARMACEUTICALS, INC.


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


    THIS CERTIFIES that, for value received, ____________, or registered
assigns, is entitled to subscribe for and purchase from Progenics
Pharmaceuticals, Inc., a Delaware corporation (hereinafter called the
"Company"), up to ___________ Warrant Shares (as hereinafter defined) at the
Warrant Purchase Price (as hereinafter defined) which shall initially be $5.00
per share at any time during the period from the date hereof to and including
the close of business on December 8, 2000.  If this Warrant is exercised prior
to the date on which the Company has completed an initial public offering (the
"IPO Date") of its Common Stock, par value $.01 per share (the "Common Stock"),
the Warrant Shares will be fully paid and nonassessable shares of Series C
Preferred Stock, $.001 par value per share, of the Company (the "Series C
Preferred Stock").  If this Warrant is exercised on or after the IPO Date, the
Warrant Shares shall be fully paid and nonassessable shares of Common Stock as
set forth in Section 5.5 herein.  Any exercise of this Warrant shall be subject
to the provisions and upon the terms and conditions hereinafter set forth.  This
Warrant is one of a series of Warrants issued by the Company in connection with
a private placement offering (the "Offering") pursuant to a Confidential Private
Placement Memorandum dated June 26, 1995.


<PAGE>

Warrant Number: 
Warrant Holder: 
Number of Warrant Shares: 
Page 2

    Section 1.     Exercise of Warrant.  The rights represented by this Warrant
may be exercised by the holder hereof, in whole or in part (in minimum lots of
1,000 Warrant Shares or such lesser amount as is at the time unexercised), upon
the surrender of this Warrant (properly endorsed if required) at the principal
office of the Company in Tarrytown, New York, or such other office or agency of
the Company as it may designate by notice in writing to the holder hereof at the
address of such holder appearing on the books of the Company at any time within
the period above named and upon payment to it by certified or bank cashier's
check of the purchase price for the Warrant Shares issuable upon such exercise. 
The Company agrees that the shares so purchased shall be deemed to be issued to
the holder hereof as the record owner of such shares as of the close of business
on the date on which this Warrant shall have been surrendered and payment made
for such shares as aforesaid.  Certificates for the Warrant Shares so purchased
shall be delivered to the holder hereof within a reasonable time, not exceeding
thirty (30) days, after the rights represented by this Warrant shall have been
so exercised, and unless this Warrant has expired, a new Warrant exercisable for
the number of Warrant Shares, if any, with respect to which this Warrant shall
not then have been exercised shall also be issued to the holder hereof within
such time.

    Section 2.     Issuance of Shares; Reservation of Series C Preferred Stock
and Common Stock.  The Company covenants and agrees that all shares which may be
issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be fully paid and nonassessable and free from all taxes, liens and
charges with respect to the issue thereof (other than taxes in respect of any
transfer occurring contemporaneously with such issue).  The Company further
covenants and agrees that during the period within which the rights represented
by this Warrant may be exercised, the Company will at all times have authorized,
and reserved, a sufficient number of shares of Series C Preferred Stock and
Common Stock to provide for the exercise of the rights represented by this
Warrant, and will at its expense expeditiously upon each such reservation of
shares use its best efforts to procure the listing thereof (subject to issuance
or notice of issuance) on all stock exchanges on which any stock of the Company
of the same class as the Warrant Shares are then listed.

    Section 3.     Payment of Taxes.  The issue of stock certificates on any
exercise of this Warrant shall be made without charge to the holder of the
Warrant for any documentary stamp tax in respect of the issue thereof.  The
Company shall not, however, be required to pay any documentary stamp tax or
other tax which may be payable in respect of any transfer involved in the issue
and delivery of stock in any name other than that of the holder of the Warrant
and the Company shall not be required to issue or deliver any such stock
certificate unless and until the person or persons requesting the issue thereof
shall have paid to the Company the amount of such tax or shall have established
to the reasonable satisfaction of the Company that such tax has been paid.

    Section 4.     Fractional Shares.  The Company shall not be required to
issue certificates representing fractions of shares of Series C Preferred Stock
or Common Stock, as the 

<PAGE>

Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 3

case may be, upon the exercise of the Warrant, but in respect of any final
fraction of a share it will make a payment in cash based on the then excess of
the market price of the Series C Preferred Stock or Common Stock, as the case
may be, over the Warrant Purchase Price.  The market price shall be the last
regular day sales price of the Series C Preferred Stock or Common Stock, as the
case may be, on a national securities exchange where the Series C Preferred
Stock or Common Stock, is traded immediately prior to determination of the
market price, or, if the Series C Preferred Stock or Common Stock, is not traded
on a national securities exchange, the mean of the reported high bid and low
asked prices of the Series C Preferred Stock or Common Stock, as the case may
be, in the over-the-counter market immediately prior to such determination, or,
if not so traded, as determined in good faith by, or at the direction of, the
Board of Directors of the Company.

    Section 5.     Adjustments.

    5.1  The term "Basic Warrant Purchase Price" with respect to any period
during which this Warrant is outstanding shall mean $5.00 per Warrant Share. 
The Basic Warrant Purchase Price shall be subject to adjustment from time to
time as hereinafter provided.  The term "Warrant Purchase Price" shall mean,
unless and until any such adjustment shall occur, the Basic Warrant Purchase
Price resulting from such adjustment and any other previous adjustments.

    5.2 If at any time or from time to time prior to the IPO Date and during
the term of this Warrant the Company shall (i) take a record of the holders of
Series C Preferred Stock for the purpose of entitling them to receive a dividend
payable in, or other distribution of, Series C Preferred Stock or any securities
convertible into or exchangeable for Series C Preferred Stock (ii) subdivide its
outstanding shares of Series C Preferred Stock into a larger number of shares,
or (iii) combine its outstanding shares of Series C Preferred Stock into a
smaller number of shares, then the number of Warrant Shares immediately after
the happening of any such event shall be adjusted so as to consist of the number
of shares of Series C Preferred Stock that the holder hereof would own or be
entitled to receive after the happening of such event if the holder had
exercised this Warrant immediately prior to the happening of such event and, in
the event of subdivision or combination, the Warrant Purchase Price in effect
immediate prior to such event shall be proportionately decreased, in the case of
a subdivision, or increased, in the case of a combination.  If the Company shall
take a record of the holders of the Series C Preferred Stock for the purpose of
entitling them to receive a dividend or distribution or subscription or purchase
rights and shall, thereafter and before the distribution thereof to
shareholders, legally abandon its plan to pay or deliver such dividend,
distribution, subscription or purchase rights, then thereafter no adjustment
shall be required by reason of the taking of such record and any such adjustment
previously made in respect thereof shall be rescinded and annulled.

    5.3 If at any time or from time to time on or after the IPO Date and during
the term of this Warrant the Company shall (i) take a record of the holders of
Common Stock for the purpose of entitling them to receive a dividend payable in,
or other distribution of, Common Stock or any 

<PAGE>

Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 4


securities convertible into or exchangeable for Common Stock (ii) subdivide its
outstanding shares of Common Stock into a larger number of shares, or (iii)
combine its outstanding shares of Common Stock into a smaller number of shares,
then the number of Warrant Shares immediately after the happening of any such
event shall be adjusted so as to consist of the number of shares of Common Stock
that the holder hereof would own or be entitled to receive after the happening
of such event if the holder had exercised this Warrant immediately prior to the
happening of such event and, in the event of subdivision or combination, the
Warrant Purchase Price in effect immediate prior to such event shall be
proportionately decreased, in the case of a subdivision, or increased, in the
case of a combination.  If the Company shall take a record of the holders of
Common Stock for the purpose of entitling them to receive a dividend or
distribution or subscription or purchase rights and shall, thereafter and before
the distribution thereof to shareholders, legally abandon its plan to pay or
deliver such dividend, distribution, subscription or purchase rights, then
thereafter no adjustment shall be required by reason of the taking of such
record and any such adjustment previously made in respect thereof shall be
rescinded and annulled.

    5.4  If there shall be effected any capital reorganization or
reclassification of the capital stock of the Company, or consolidation or merger
or amalgamation of the Company with another corporation, or the sale of all or
substantially all of its assets to another corporation (each such event being
hereinafter called a "Major Corporate Event") then, as a condition of such Major
Corporate Event, lawful and adequate provision shall be made whereby the holder
hereof shall thereafter have the right to purchase and receive upon the basis
and upon the terms and conditions specified in this Warrant and in lieu of the
Warrant Shares immediately theretofore purchasable and receivable upon the
exercise of the rights represented hereby, (i) such shares of stock, securities
or assets as may be issued or payable with respect to or in exchange for a
number of outstanding Warrant Shares equal to the number of Warrant Shares
immediately theretofore purchasable and receivable upon the exercise of the
rights represented hereby had such Major Corporate Event not taken place, and
(ii) if such Major Corporate Event is with any person (or any affiliate of such
person) who shall have made a purchase, tender or exchange offer which was
accepted by the holders of more than ten percent (10%) of the outstanding shares
of the class of securities then-purchasable or receivable upon the exercise of
this Warrant, the holder of this Warrant shall have been given a reasonable
opportunity then to elect to receive, either (x) the stock, securities, cash or
properties he would have received pursuant to clause (i) immediately preceding
or (y) the stock, securities, cash or properties issued to previous holders of
such securities in accordance with such offer, or the equivalent thereof.  In
any such case appropriate provision shall be made with respect to the rights and
interests of the holder of this Warrant to the end that the provisions hereof
(including, without limitation, provisions for adjustment of the Warrant
Purchase Price and of the number of shares purchasable upon the exercise of this
Warrant) shall thereafter be applicable, as nearly as may be, in relation to any
shares of stock, securities or assets thereafter deliverable upon the exercise
hereof.  The Company shall not effect any such Major Corporate Event, unless
prior to or simultaneously with the consummation thereof the successor
corporation (if other than the Company) resulting from such consolidation 


<PAGE>

Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 5



or merger or amalgamation or the corporation purchasing such assets shall assume
by written instrument executed and mailed or delivered to the registered holder
hereof at the last address of such holder appearing on the books of the Company,
the obligation to deliver to such holder such shares of stock, securities or
assets as, in accordance with the foregoing provisions, such holder may be
entitled to purchase.  The above provisions of this paragraph shall similarly
apply to each successive Major Corporate Event.

    5.5  (a)  If at any time which is prior to the IPO Date the Company shall
(i) issue any shares of Series C Preferred Stock ("Additional Series C Stock"),
(ii) issue any securities convertible into or exchangeable for Series C
Preferred Stock ("Series C Convertible Securities") or (iii) issue any warrants
or other rights to subscribe for Additional Series C Stock or Series C
Convertible Securities and the consideration per share received upon issuance of
any such Additional Series C Stock or which may at any time thereafter be
payable to the Company upon issuance of such Additional Series C Stock pursuant
to such warrants or rights or pursuant to the terms of such Series C Convertible
Securities is less than the Current Market Price (as defined below) per share of
the Series C Preferred Stock, then no adjustment to the number of Warrant Shares
shall be made, and adjustments, if any, to the number of shares of Common Stock
issuable upon exercise of the Series C Preferred Stock shall be made in
accordance with the terms of the Series C Preferred Stock.

         (b)  On the IPO Date, the Warrant Shares issuable upon the exercise of
this Warrant shall be adjusted so as to consist of the number of shares of
Common Stock that would be received upon conversion of the Series C Preferred
Stock that the holder hereof would own or be entitled to own if such holder had
exercised this Warrant and converted the Series C Preferred Stock received upon
exercise of this Warrant immediately prior to the IPO Date.  On the IPO Date,
the Warrant Purchase Price shall be adjusted to that price determined by
multiplying the Warrant Purchase Price immediately prior to the IPO Date by a
fraction (i) the numerator of which is the number of Warrant Shares in effect
immediately prior to the IPO Date, and (ii) the denominator of which is the
newly applicable number of Warrant Shares on the IPO Date following adjustment
as set forth above in this Section 5.5(b).

    5.6  If at any time which is after the IPO Date but before December 31,
1996 the Company shall (except as hereinafter provided) (i) issue any shares of
Common Stock ("Additional Common Stock"), (ii) issue any securities convertible
into or exchangeable for Common Stock ("Common Stock Convertible Securities") or
(iii) issue any warrants or other rights to subscribe for Additional Common
Stock or Common Stock Convertible Securities and the consideration per share
received upon issuance of any such Additional Common Stock (or in the case of
Common Stock Convertible Securities, the consideration per share of Common Stock
assuming such Common Stock Convertible Securities had been so converted) or
which may at any time thereafter be payable to the Company upon issuance of
Additional Common Stock pursuant to such warrants or rights is less than the
Warrant Purchase Price, then the Warrant Purchase Price shall be reduced to such
lower price.  Upon such an event, the number of Warrant 

<PAGE>

Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 6

Shares shall be adjusted to that number determined by multiplying the number of
Warrant Shares immediately prior to such adjustment by a fraction (i) the
numerator of which is the Warrant Purchase Price in effect immediately prior to
the such event, and (ii) the denominator of which is the newly applicable
Warrant Purchase Price following adjustment as set forth above in this Section
5.6.

    5.7  If at any time which is after the IPO Date but after December 31, 1996
the Company shall (except as hereinafter provided) (i) issue any Additional
Common Stock, (ii) issue any Common Stock Convertible Securities or (iii) issue
any warrants and other rights to subscribe for Additional Common Stock or Common
Stock Convertible Securities and the consideration per share received upon
issuance of any such Additional Common Stock (or in the case of Common Stock
Convertible Securities, the consideration per share of Common Stock assuming
such Common Stock Convertible Securities had been so converted) or which may at
any time thereafter be payable to the Company upon issuance of Additional Common
Stock pursuant to such warrants or rights is less than the Current Market Price
per share of the Common Stock, then the Warrant Purchase Price shall be reduced
to a price determined by dividing (a) the sum of (i) the total number of shares
of Capital Stock (as defined below) outstanding immediately prior to such
issuance multiplied by the Warrant Purchase Price in effect immediately prior to
such issuance and (ii) the consideration received by the Company upon such
issuance, by (b) the number of shares of Capital Stock outstanding immediately
after such issuance.  Upon such an event, the number of Warrant Shares shall be
adjusted to that number determined by a fraction (i) the numerator of which is
the Warrant Purchase Price in effect immediately prior to such event, and (ii)
the denominator of which is the newly applicable Warrant Purchase Price
following such adjustments as set forth above in this Section 5.7. 

    5.8  (a) "Current Market Price" per share of a security for the purposes of
any provision of this Warrant at the date herein specified shall mean the price
per share of such security on such date determined by the Board of Directors as
provided below.  The Current Market Price shall be the average of the daily
closing price per share of such security for thirty (30) consecutive business
days ending no more than fifteen (15) business days before the day in question
(as adjusted for any stock dividend, split, combination or reclassification that
took effect during such 30-day period).  The closing price for each day shall be
the last reported sales price regular way or, in the case no such reported sales
take place on such day, the average of the last reported bid and asked prices
regular way, in either case, on the principal national securities exchange on
which such security is listed or admitted to trading, unless such principal
national securities exchange is a regional securities exchange and such security
is also quoted on the Nasdaq Stock Market, or if not listed or admitted to
trading on a national securities exchange or if such principal securities
exchange is a regional securities exchange and such security is also quoted on
the Nasdaq Stock Market, the average of the highest bid and the lowest asked
prices quoted on the Nasdaq Stock Market, or, if not so quoted, as reported by
the National Quotation Bureau, Inc.; provided, however, that if such security is
not traded in such manner that any of the quotations referred to above is
available for the period required hereunder, the Current 


<PAGE>


Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 7



Market Price per share of such security shall be deemed to be the fair market
value as determined by the Board of Directors in good faith, irrespective of any
accounting treatment.

         (b)  "Capital Stock" shall mean the Common Stock and all other capital
stock of the Company that is convertible into Common Stock.  For purposes of
this Warrant, the number of shares of Capital Stock outstanding at any time
shall equal the number of shares of Common Stock outstanding plus the total
number of shares of Common Stock into which all other capital stock of the
Company outstanding at such time is convertible.

         (c)  To the extent that any such issuance shall be for a consideration
other than cash, then, the amount of such consideration shall be deemed to be
the fair value of such consideration at the time of such issuance as determined
in good faith by the Company's Board of Directors.  

         (d)  If the Company takes any action after the date hereof, other than
actions described above, which would have an adverse effect upon the rights of
the holder of this Warrant, then the Warrant Purchase Price shall be adjusted in
such manner and at such time as the Company's Board of Directors shall in good
faith determine to be equitable under the circumstances.

         (e)  No adjustments shall be made to the number of Warrant Shares or
the Warrant Purchase Price under this Section 5.5 in respect of (1) Common Stock
or any other capital stock of the Company to be issued pursuant to the Company's
1989 Stock Option Plan, 1993 Stock Option Plan, 1993 Executive Stock Option Plan
or any other stock options or warrants granted or sold to employees,
consultants, advisors or directors of the Company relating to the provision of
services to the Company; (2) shares of Common Stock or any other capital stock
of the Company issued by the Company under provisions of the Company's
Certificate of Incorporation as from time to time in effect or by virtue of
agreements designed to protect against dilution; and (3) shares of Common Stock
or any other capital stock of the Company issued or reserved for issuance by the
Company upon conversion of any capital stock of the Company.

    5.9  Upon any adjustment of the Warrant Purchase Price or the number of
Warrant Shares, then and in each such case the Company shall give written notice
thereof, by first class mail, postage prepaid, addressed to the registered
holder of this Warrant at the address of such holder as shown on the books of
the Company, which notice shall state the Warrant Purchase Price resulting from
such adjustment and/or the increase or decrease, if any, in the number of shares
purchasable upon the exercise of this Warrant, setting forth in reasonable
detail the method of calculation and the facts upon which such calculation is
based.

<PAGE>




Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 8


    5.10 In case at any time:

          (i)  the Company shall pay any dividend payable in stock upon the
               Class of securities then-purchasable or receivable upon the
               exercise of this Warrant or make any distribution (other than
               regular cash dividends out of earned surplus) to the holders of
               such securities;
              
         (ii)  the Company shall offer for subscription pro rata to the holders
               of the class of securities then-purchasable or receivable upon
               the exercise of this Warrant any additional shares of stock of
               any class or other rights;
              
        (iii)  there shall be any Major Corporate Event;
              
         (iv)  the Company shall issue Additional Series C Stock, Series C
               Convertible Securities, Additional Common Stock or Common Stock
               Convertible Securities; or 
              
          (v)  there shall be a voluntary or involuntary dissolution,
               liquidation or winding up of the Company;

then, in any one or more of such cases, the Company shall give to the holder of
this Warrant (a) at least twenty days' prior written notice of the date on which
the books of the Company shall close or a record shall be taken for such
dividend, distribution or subscription rights or for determining rights to vote
in respect of any such reorganization, reclassification, consolidation, merger,
sale, amalgamation, dissolution, liquidation or winding up, and (b) in the case
of any such reorganization, reclassification, consolidation, merger,
amalgamation, sale, dissolution, liquidation or winding up, at least twenty
days' prior written notice of the date when the same shall take place.  Such
notice in accordance with the foregoing clause (a) shall also specify, in the
case of any such dividend, distribution or subscription rights, the date on
which the holders of such securities shall be entitled thereto, and such notice
in accordance with the foregoing clause (b) shall also specify the date on which
the holders of such securities shall be entitled to exchange their securities
for securities or other property deliverable upon such reorganization,
reclassification, consolidation, merger, amalgamation, sale, dissolution,
liquidation or winding up, as the case may be.  Each such written notice shall
be given by first class mail, postage prepaid, addressed to the holder of this
Warrant at the address of such holder as shown on the books of the Company.


<PAGE>




Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 9


    Section 6.     Execution of Agreement.  The holder hereof agrees that upon
exercise, in whole or in part, of this Warrant, he will execute and deliver to
the Company an agreement substantially in the form of the agreement referred to
in the legend at the head of this Warrant, and the certificates representing any
securities, so acquired upon exercise may bear a legend substantially as
referred to in the aforesaid agreement and that the Company may issue
appropriate stop transfer order instructions to any and all transfer agents of
the Company's.

    Section 7.  No Rights as a Shareholder.  The Warrant shall not entitle the
holder hereof to any rights as a stockholder of the Company, including, without
limitation, voting rights.

    Section 8.  Transferability.  This Warrant and all rights hereunder are,
subject to the provisions of the agreement referred to in the legend at the head
of this Warrant, transferable, in whole or in part, at the office or agency of
the Company referred to in the second paragraph hereof by the holder hereof in
person or by duly authorized attorney, upon surrender of this Warrant properly
endorsed.  Each taker and holder of this Warrant, by taking or holding the same,
consents and agrees that this Warrant, when endorsed in blank, shall be deemed
negotiable, and that the holder hereof, when so endorsed, may be treated by the
Company and all other persons dealing with this Warrant as the absolute owner
hereof for any purposes and as the person entitled to exercise the rights
represented by this Warrant, or to the transfer hereof on the books of the
Company, any notice to the contrary notwithstanding; but until each transfer on
such books, the Company may treat the registered holder hereof as the owner
hereof for all purposes.

    Section 9.  Exchange of Warrant.  This Warrant is exchangeable, upon the
surrender hereof by the holder hereof at such office or agency of the Company,
for new Warrants of like tenor representing in the aggregate the right to
subscribe for and purchase the number of shares which may be subscribed for and
purchased hereunder, each of such new Warrants to represent the right to
subscribe for and purchase such number of shares as shall be designated by such
holder hereof at the time of such surrender. 

<PAGE>

Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 10


    IN WITNESS WHEREOF, Progenics Pharmaceuticals, Inc. has caused this Warrant
to be signed by its duly authorized officers under its corporate seal, and this
Warrant to be dated this 8th day of December, 1995.


ATTEST:                            PROGENICS PHARMACEUTICALS, INC.


- ------------------------           ---------------------------------- 
Robert A. McKinney                 Paul J. Maddon, M.D., Ph.D.
Assistant Secretary                President 

<PAGE>

Warrant Number:  
Warrant Holder:  
Number of Warrant Shares:  
Page 11



                      [FORM OF LETTER TO EXERCISE THE WARRANTS]
                                SUBSCRIPTION AGREEMENT


                                       Date__________________  


To Progenics Pharmaceuticals, Inc.


    The undersigned, pursuant to the provisions set forth in the within
Warrant, hereby agrees to subscribe for and purchase the number of shares of
[Series C Preferred Stock] [Common Stock] set forth below which are covered by
such Warrant, and makes payment herewith in full therefor at the price per share
provided by this Warrant.

    Choose One:

    ----------     Exercise Warrant in full as to _______ shares.

    ----------     Exercise Warrant as to _______ shares and request the
                   issuance of a new Warrant for the balance of _______ shares.


                         Signature                                             
                                   --------------------------------------------

                        Print Name:                                         
                                   --------------------------------------------

                          Address:                                         
                                   --------------------------------------------

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


   
<PAGE>

THIS WARRANT AND THE SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE NOT BEEN   
REGISTERED UNDER THE SECURITIES ACT OF 1933.  THIS WARRANT HAS BEEN ACQUIRED 
FOR INVESTMENT AND NOT WITH A VIEW TO THE DISTRIBUTION HEREOF OR OF THE 
SECURITIES ISSUABLE UPON EXERCISE HEREOF WITHIN THE MEANING OF THE SECURITIES 
ACT OF 1933 AND THE RULES AND REGULATIONS THEREUNDER. NEITHER THIS WARRANT 
NOR THE SECURITIES ISSUABLE UPON EXERCISE HEREOF MAY BE TRANSFERRED IN THE 
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES UNDER THE 
SECURITIES ACT OF 1933 OR UPON RECEIPT BY THE COMPANY OF AN OPINION 
SATISFACTORY TO THE COMPANY OF COUNSEL TO THE PROPOSED TRANSFEREE OR THE 
COMPANY AS TO AN EXEMPTION THEREFROM.
   
                         Warrant Number:          
                         Warrant to Subscribe for 
                         Shares of Stock          
   
   
                   STOCK PURCHASE WARRANT
   
           To Subscribe for and Purchase Stock of
   
               PROGENICS PHARMACEUTICALS, INC.
   
   
                      -------------------     
   
   
     THIS CERTIFIES that, for value received,                , or registered  
assigns, is entitled to subscribe for and purchase from Progenics    
Pharmaceuticals, Inc., a Delaware corporation (hereinafter called the    
"Company"), up to          Warrant Shares (as hereinafter defined) at any 
time during the period from the Initial Exercise Date (as hereinafter 
defined) to and including the close of business on March 12, 2002 at the 
Warrant Purchase Price (as hereinafter defined).  Upon the exercise of this 
Warrant, the Warrant Shares shall be fully paid and nonassessable shares of 
the Company's Common Stock, par value $.01 per share (the "Common Stock").  
Any exercise of this Warrant shall be subject to the provisions and upon the 
terms and conditions hereinafter set forth.  This Warrant is one of a series 
of Warrants issued by the Company in connection with a loan guarantee by      
         and                (the "Guarantee") pursuant to a Loan Guarantee 
Agreement by and among the Company,                  and                 LLC 
dated March 12, 1997.  The Initial Exercise Date shall be the earliest of the 
completion of an IPO (as hereinafter defined), the completion of a Corporate 
Partnership (as hereinafter defined), the completion of a Sale (as 
hereinafter defined) or December 31, 1997.
   
     Section 1.     Exercise of Warrant. The rights represented by this 
Warrant may be exercised by the holder hereof, in whole or in part (in 
minimum lots of 1,000 Warrant Shares or such lesser amount as is at the 
time unexercised), upon the surrender of this Warrant (properly endorsed 
if required) at the principal office of the Company in Tarrytown, New 
York, or such other office or agency of the Company as it may designate by 
notice in writing to the holder 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 2

hereof at the  address of such holder appearing on the books of the Company 
at any time within the period above named and upon (i) payment to it by 
certified or bank cashier's check of the purchase price for the Warrant 
Shares issuable upon such exercise (ii) in the event that the holder is also 
the holder of a note issued by the Company and the outstanding principal 
amount of, and/or accrued but unpaid interest on, such note is equal to or 
greater than the purchase price for the Warrant Shares issuable upon such 
exercise, by decreasing the outstanding  principal amount of, and/or accrued 
but unpaid interest on, such note by the amount of such purchase price,or 
(iii) by the holder surrendering its rights to a number of Warrant Shares 
having an aggregate Fair Market Value (as hereinafter defined) on the date of 
exercise equal to or greater than the required purchase price for the Warrant 
Shares issuable upon such exercise, in which case the holder would receive 
the number of Warrant Shares to which it would otherwise be entitled upon 
such exercise, less the surrendered shares.  The Company agrees that the 
shares so purchased shall be deemed to be issued to the holder hereof as the 
record owner of such shares as of the close of business on the date on which 
this Warrant shall have been surrendered and payment made for such shares as 
aforesaid. Certificates for the Warrant Shares so purchased shall be 
delivered to the holder hereof within a reasonable time, not exceeding thirty 
(30) days, after the rights represented by this Warrant shall have been so 
exercised, and unless this Warrant has expired, a new Warrant exercisable for 
the number of Warrant Shares, if any, with respect to which this Warrant 
shall not then have been exercised shall also be issued to the holder hereof 
within such time.  For purposes of this Section 1, "Fair Market Value" of a 
share shall mean (a) the closing price (or if there is no closing price, the 
average of the last reported bid and asked prices regular way) on the day 
immediately prior to the date of exercise (or if not available on such day, 
on the last day on which such price is available if such price is available 
within the prior fifteen days) on the principal national securities exchange 
is a regional securities exchange and such security is also quoted on the 
NASDAQ Stock Market, or if not listed or admitted to trading on a national 
securities exchange or if such principal securities exchange is a regional 
securities exchange and such security is also quoted on the NASDAQ Stock 
Market, the average of the highest bid and the lowest asked priced quoted on 
the NASDAQ Stock Market, or, if not so quoted, as reported by the National 
Quotation Bureau, Inc. minus (b) the purchase price for one Warrant Share 
issuable upon exercise, provided, that, if the Company's shares are not 
traded in such manner that any of the quotations referred to above is 
available for the day of valuation hereunder, Fair Market Value shall be 
deemed to be the fair market value as determined by the Board of Directors in 
good faith, irrespective of any accounting treatment. 
   
     Section 2.     Issuance of Shares; Reservation of Common Stock.  The 
Company covenants and agrees that all shares which may be issued upon the 
exercise of the rights represented by this Warrant will, upon issuance, be 
fully paid and nonassessable and free from all taxes, liens and charges with 
respect to the issue thereof (other than taxes in respect of any transfer 
occurring contemporaneously with such issue).  The Company further covenants 
and agrees that during the period within which the rights represented by this 
Warrant may be exercised, the Company will at all times have authorized, and 
reserved, a sufficient number of shares of Common Stock to provide for the 
exercise of the rights represented by this Warrant, 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 3

and will at its expense expeditiously upon each such reservation of shares 
use its best efforts to procure the listing thereof (subject to issuance or 
notice of issuance) on all stock exchanges on which any stock of the Company 
of the same class as the Warrant Shares are then listed.
   
     Section 3.     Payment of Taxes.  The issue of stock certificates on any 
exercise of this Warrant shall be made without charge to the holder of the 
Warrant for any documentary stamp tax in respect of the issue thereof.  The 
Company shall not, however, be required to pay any documentary stamp tax or 
other tax which may be payable in respect of any transfer involved in the 
issue and delivery of stock in any name other than that of the holder of the 
Warrant and the Company shall not be required to issue or deliver any such 
stock certificate unless and until the person or persons requesting the issue 
thereof shall have paid to the Company the amount of such tax or shall have 
established to the reasonable satisfaction of the Company that such tax has 
been paid.
   
     Section 4.     Fractional Shares.  The Company shall not be required to 
issue certificates representing fractions of shares of Common Stock upon the 
exercise of the Warrant, but in respect of any final fraction of a share it 
will make a payment in cash based on the then excess of the market price of 
the Common Stock over the Warrant Purchase Price.  The market price shall be 
the last regular day sales price of the Common Stock on a national securities 
exchange where the Common Stock is traded immediately prior to determination 
of the market price, or, if the Common Stock is not traded on a national 
securities exchange, the mean of the reported high bid and low asked prices 
of the Common Stock in the over-the-counter market immediately prior to such 
determination, or, if not so traded, as determined in good faith by, or at 
the direction of, the Board of Directors of the Company.
   
     Section 5.     Adjustments.
   
     5.1  The term "Basic Warrant Purchase Price" with respect to any period 
during which this Warrant is outstanding shall mean: (i) if the Company and 
Bristol-Myers Squibb ("Bristol") enter into a corporate partnership (the 
"Corporate Partnership") involving a upfront payment to the Company by 
Bristol of at least $8.0 million prior to December 31, 1997, $3.00 per share, 
unless, subsequent to the closing of the Corporate Partnership but prior to 
December 31, 1997, (a) the Company has completed an initial public offering 
(an "IPO") of its Common Stock, in which case the Basic Warrant Purchase 
Price shall, upon completion of the IPO, become 50% of the gross sales price 
of a share of Common Stock in the IPO, or (b) a Sale (as hereinafter defined) 
of the Company occurs, in which case the Basic Warrant Purchase Price shall, 
upon completion of a Sale, become 50% of the per share Sale Price (as 
hereinafter defined), provided that no change shall be made in the Basic 
Warrant Purchase Price with respect to a Sale if an IPO has previously been 
completed; (ii)  if an IPO occurs prior to December 31, 1997, 50% of the 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 4

gross sales price of a share of Common Stock in the IPO, even if subsequent 
to the IPO, but prior to December 31, 1997, the Company enters into a 
Corporate Partnership or there is a Sale of the Company; (iii) if a Sale of 
the Company occurs prior to December 31, 1997, 50% of the per share Sale 
Price, or (iv) if, prior to December 31, 1997, the Company does not enter 
into a Corporate Partnership, the IPO does not occur and there is no Sale of 
the Company, $1.10 per share.  "Sale" is defined herein as (x) a sale by the 
stockholders of the Company, in a single transaction or a series of related 
transactions, of the majority of the Company's outstanding stock to a single 
buyer or group of related buyers, (y) a sale by the Company  of all or 
substantially all of the Company's assets, or (z) a merger in which the 
stockholders of the Company receive in exchange for their stock in the 
Company cash or stock of another corporation.  "Sale Price" is defined herein 
as the average consideration received by stockholders per share of Common 
Stock from the Sale of the Company, with the value of any non-cash 
consideration to be determined by the Board of Directors of the Company.  The 
Basic Warrant Purchase Price shall be subject to adjustment from time to time 
as hereinafter provided. The term "Warrant Purchase Price" shall mean, unless 
and until any such adjustment shall occur, the Basic Warrant Purchase Price 
resulting from such adjustment and any other previous adjustments.
   
     5.2  If during the term of this Warrant the Company shall (i) take a 
record of the holders of Common Stock for the purpose of entitling them to 
receive a dividend payable in, or other distribution of, Common Stock or any 
securities convertible into or exchangeable for Common Stock (ii) subdivide 
its outstanding shares of Common Stock into a larger number of shares, or 
(iii) combine its outstanding shares of Common Stock into a smaller number of 
shares, then the number of Warrant Shares immediately 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 4

after the happening of any such event shall be adjusted so as to consist of 
the number of shares of Common Stock that the holder hereof would own or be 
entitled to receive after the happening of such event if the holder had 
exercised this Warrant immediately prior to the happening of such event and, 
in the event of subdivision or combination, the Warrant Purchase Price in 
effect immediately prior to such event shall be proportionately decreased, in 
the case of a subdivision, or increased, in the case of a combination.  If 
the Company shall take a record of the holders of Common Stock for the 
purpose of entitling them to receive a dividend or distribution or 
subscription or purchase rights and shall, thereafter and before the 
distribution thereof to shareholders, legally abandon its plan to pay or 
deliver such dividend, distribution, subscription or purchase rights, then 
thereafter no adjustment shall be required by reason of the taking of such 
record and any such adjustment previously made in respect thereof shall be 
rescinded and annulled.
   
     5.3  If there shall be effected any capital reorganization or 
reclassification of the capital stock of the Company, or consolidation or 
merger or amalgamation of the Company with another corporation, or the sale 
of all or substantially all of its assets to another corporation (each such 
event being hereinafter called a "Major Corporate Event") then, as a 
condition of such Major Corporate Event, lawful and adequate provision shall 
be made whereby the holder hereof shall thereafter have the right to purchase 
and receive upon the basis and upon the terms and conditions specified in 
this Warrant and in lieu of the Warrant Shares immediately theretofore 
purchasable and receivable upon the exercise of the rights represented 
hereby, (i) such shares of stock, securities or assets as may be issued or 
payable with respect to or in exchange for a number of outstanding Warrant 
Shares equal to the number of Warrant Shares immediately 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 5

theretofore purchasable and receivable upon the exercise of the rights 
represented hereby had such Major Corporate Event not taken place, and (ii) 
if such Major Corporate Event is with any person (or any affiliate of such 
person) who shall have made a purchase, tender or exchange offer which was 
accepted by the holders of more than ten percent (10%) of the outstanding 
shares of the class of securities then-purchasable or receivable upon the 
exercise of this Warrant, the holder of this Warrant shall have been given a 
reasonable opportunity then to elect to receive, either (x) the stock, 
securities, cash or properties he would have received pursuant to clause (i) 
immediately preceding or (y) the stock, securities, cash or properties issued 
to previous holders of such securities in accordance with such offer, or the 
equivalent thereof.  In any such case appropriate provision shall be made 
with respect to the rights and interests of the holder of this Warrant to the 
end that the provisions hereof (including, without limitation, provisions for 
adjustment of the Warrant Purchase Price and of the number of shares 
purchasable upon the exercise of this Warrant) shall thereafter be 
applicable, as nearly as may be, in relation to any shares of stock, 
securities or assets thereafter deliverable upon the exercise hereof.  The 
Company shall not effect any such Major Corporate Event, unless prior to or 
simultaneously with the consummation thereof the successor corporation (if 
other than the Company) resulting from such consolidation or merger or 
amalgamation or the corporation purchasing such assets shall assume by 
written instrument executed and mailed or delivered to the registered holder 
hereof at the last address of such holder appearing on the books of the 
Company, the obligation to deliver to such holder such shares of stock, 
securities or assets as, in accordance with the foregoing provisions, such 
holder may be entitled to purchase.  The above provisions of this paragraph 
shall similarly apply to each successive Major Corporate Event.
   
     5.4  If the Company shall (except as hereinafter provided) (i) issue any 
shares of Common Stock ("Additional Common Stock"), (ii) issue any securities 
convertible into or exchangeable for Common Stock ("Common Stock Convertible 
Securities") or (iii) issue any warrants and other rights to subscribe for 
Additional Common Stock or Common Stock Convertible Securities and the 
consideration per share received upon issuance of any such Additional Common 
Stock (or in the case of Common Stock Convertible Securities, the 
consideration per share of Common Stock assuming such Common Stock 
Convertible Securities had been so converted) or which may at any time 
thereafter be payable to the Company upon issuance of Additional Common Stock 
pursuant to such warrants or rights or is less than the Current Market Price 
per share of the Common Stock, then the Warrant Purchase Price shall be 
reduced to a price determined by dividing (a) the sum of (i) the total number 
of shares of Capital Stock (as defined below) outstanding immediately prior 
to such issuance multiplied by the Warrant Purchase Price in effect 
immediately prior to such issuance and (ii) the consideration received by the 
Company upon such issuance, by (b) the number of shares of Capital Stock 
outstanding immediately after such issuance.  Upon such an event, the number 
of Warrant Shares shall be adjusted to that number determined by a fraction 
(i) the numerator of which is the Warrant Purchase Price in effect 
immediately prior to such event, and (ii) the denominator of which is the 
newly applicable Warrant Purchase Price following such adjustments as set 
forth above in this Section 5.4. 
   
<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 6

     5.5  (a)  "Current Market Price" per share of a security for the 
purposes of any provision of this Warrant at the date herein specified shall 
mean the price per share of such security on such date determined by the 
Board of Directors as provided below.  The Current Market Price shall be the 
average of the daily closing price per share of such security for thirty (30) 
consecutive business days ending no more than fifteen (15) business days 
before the day in question (as adjusted for any stock dividend, split, 
combination or reclassification that took effect during such 30-day period).  
The closing price for each day shall be the last reported sales price regular 
way or, in the case no such reported sales take place on such day, the 
average of the last reported bid and asked prices regular way, in either 
case, on the principal national securities exchange on which such security is 
listed or admitted to trading, unless such principal national securities 
exchange is a regional securities exchange and such security is also quoted 
on the Nasdaq Stock Market, or if not listed or admitted to trading on a 
national securities exchange or if such principal securities exchange is a 
regional securities exchange and such security is also quoted on the Nasdaq 
Stock Market, the average of the highest bid and the lowest asked prices 
quoted on the Nasdaq Stock Market, or, if not so quoted, as reported by the 
National Quotation Bureau, Inc.; provided, however, that if such security is 
not traded in such manner that any of the quotations referred to above is 
available for the period required hereunder, the Current Market Price per 
share of such security shall be deemed to be the fair market value as 
determined by the Board of Directors in good faith, irrespective of any 
accounting treatment. 
   
          (b)  "Capital Stock" shall mean the Common Stock and all other 
capital stock of the Company that is convertible into Common Stock.  For 
purposes of this Warrant, the number of shares of Capital Stock outstanding 
at any time shall equal the number of shares of Common Stock outstanding plus 
the total number of shares of Common Stock into which all other capital stock 
of the Company outstanding at such time is convertible.
   
          (c)  To the extent that any such issuance shall be for a 
consideration other than cash, then, the amount of such consideration shall 
be deemed to be the fair value of such consideration at the time of such 
issuance as determined in good faith by the Company's Board of Directors.  
   
          (d)  If the Company takes any action after the date hereof, other 
than actions described above, which would have an adverse effect upon the 
rights of the holder of this Warrant, then the Warrant Purchase Price shall 
be adjusted in such manner and at such time as the Company's Board of 
Directors shall in good faith determine to be equitable under the 
circumstances.
   
          (e)  No adjustments shall be made to the number of Warrant Shares 
or the Warrant Purchase Price under this Section 5 in respect of (1) Common 
Stock or any other capital stock of the Company to be issued pursuant to the 
Company's 1989 Stock Option Plan, 1993 Stock Option Plan, 1993 Executive 
Stock Option Plan, 1996 Stock Incentive Plan or any other stock options or 
warrants granted or sold to employees, consultants, advisors or directors of 
the 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 7

Company relating to the provision of services to the Company; (2) shares of 
Common Stock or any other capital stock of the Company issued by the Company 
under provisions of the Company's Certificate of Incorporation as from time 
to time in effect or by virtue of agreements designed to protect against 
dilution; and (3) shares of Common Stock or any other capital stock of the 
Company issued or reserved for issuance by the Company upon conversion of any 
capital stock of the Company.
   
     5.6  Upon any adjustment of the Warrant Purchase Price or the number of 
Warrant Shares, then and in each such case the Company shall give written 
notice thereof, by first class mail, postage prepaid, addressed to the 
registered holder of this Warrant at the address of such holder as shown on 
the books of the Company, which notice shall state the Warrant Purchase Price 
resulting from such adjustment and/or the increase or decrease, if any, in 
the number of shares purchasable upon the exercise of this Warrant, setting 
forth in reasonable detail the method of calculation and the facts upon which 
such calculation is based.
   
     5.7  In case at any time:
   
          (i)  the Company shall pay any dividend payable in stock upon the
               class of securities then-purchasable or receivable upon the
               exercise of this Warrant or make any distribution (other than
               regular cash dividends out of earned surplus) to the holders of
               such securities;
   
          (ii) the Company shall offer for subscription pro rata to the holders
               of the class of securities then-purchasable or receivable upon
               the exercise of this Warrant any additional shares of stock of
               any class or other rights;
   
         (iii) there shall be any Major Corporate Event;
  
          (iv) the Company shall issue Additional Common Stock or Common Stock
               Convertible Securities; or 
   
          (v)  there shall be a voluntary or involuntary dissolution,
               liquidation or winding up of the Company;
   
then, in any one or more of such cases, the Company shall give to the holder 
of this Warrant (a) at least twenty days' prior written notice of the date on 
which the books of the Company shall close or a record shall be taken for 
such dividend, distribution or subscription rights or for determining rights 
to vote in respect of any such reorganization, reclassification, 
consolidation, merger, sale, amalgamation, dissolution, liquidation or 
winding up, and (b) in the case of any such reorganization, reclassification, 
consolidation, merger, amalgamation, sale, dissolution, liquidation or 
winding up, at least twenty days' prior written notice of the date when the 
same shall take place.  Such notice in accordance with the foregoing clause 
(a) shall also specify, in 

<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 8

the case of any such dividend, distribution or subscription rights, the date 
on which the holders of such securities shall be entitled thereto, and such 
notice in accordance with the foregoing clause (b) shall also specify the 
date on which the holders of such securities shall be entitled to exchange 
their securities for securities or other property deliverable upon such 
reorganization, reclassification, consolidation, merger, amalgamation, sale, 
dissolution, liquidation or winding up, as the case may be.  Each such 
written notice shall be given by first class mail, postage prepaid, addressed 
to the holder of this Warrant at the address of such holder as shown on the 
books of the Company.
   
     Section 6.     Legend.  The holder hereof agrees that upon exercise, in 
whole or in part, of this Warrant, the certificates representing any 
securities, so acquired upon exercise may bear a legend substantially as set 
forth below and that the Company may issue appropriate stop transfer order 
instructions to any and all transfer agents of the Company.
   
          "The securities represented by this certificate have not
           been registered under the Securities Act of 1933, as
           amended, and cannot be sold or otherwise transferred except
           pursuant to registration under said Act or in compliance
           with an exception therefrom."
   
     Section 7.  No Rights as a Shareholder.  The Warrant shall not entitle 
the holder hereof to any rights as a stockholder of the Company, including, 
without limitation, voting rights.
   
     Section 8.  Transferability.  This Warrant and all rights hereunder are, 
subject to the provisions regarding stock transfer restrictions and rights of 
first refusal as set forth in Exhibit B attached to this Warrant, 
transferable, in whole or in part, at the office or agency of the Company 
referred to in the second paragraph hereof by the holder hereof in person or 
by duly authorized attorney, upon surrender of this Warrant properly 
endorsed.  Each taker and holder of this Warrant, by taking or holding the 
same, consents and agrees that this Warrant, when endorsed in blank, shall be 
deemed negotiable, and that the holder hereof, when so endorsed, may be 
treated by the Company and all other persons dealing with this Warrant as the 
absolute owner hereof for any purposes and as the person entitled to exercise 
the rights represented by this Warrant, or to the transfer hereof on the 
books of the Company, any notice to the contrary notwithstanding; but until 
each transfer on such books, the Company may treat the registered holder 
hereof as the owner hereof for all purposes.
   
     Section 9.  Exchange of Warrant.  This Warrant is exchangeable, upon the 
surrender hereof by the holder hereof at such office or agency of the 
Company, for new Warrants of like tenor representing in the aggregate the 
right to subscribe for and purchase the number of shares which may be 
subscribed for and purchased hereunder, each of such new Warrants to 
represent the right to subscribe for and purchase such number of shares as 
shall be designated by such holder hereof at the time of such surrender.
   
<PAGE>

Warrant Number:
Warrant Holder:
Number of Warrant Shares:
Page 9


     IN WITNESS WHEREOF, Progenics Pharmaceuticals, Inc. has caused this 
Warrant to be signed by its duly authorized officers under its corporate 
seal, and this Warrant to be dated this 9th day of June, 1997.
   
   
                                         PROGENICS PHARMACEUTICALS, INC.
   
   
   
                                         ------------------------------
                                         Paul J. Maddon, M.D., Ph.D.
                                         President
   
   
ATTEST:
   
   
   
- ----------------------------
Robert A. McKinney
Assistant Secretary
       
<PAGE>
   

          [FORM OF LETTER TO EXERCISE THE WARRANTS]
   
   
   
                                                    Date ----------------------
   
   
To Progenics Pharmaceuticals, Inc.
   
   
     The undersigned, pursuant to the provisions set forth in the within 
Warrant, hereby agrees to subscribe for and purchase the number of shares of 
Common Stock set forth below which are covered by such Warrant, and makes 
payment herewith in full therefor at the price per share provided by this 
Warrant.
   
     Choose One:
   
     -----------   Exercise Warrant in full as to _______ shares.
   
     -----------   Exercise Warrant as to _______ shares and request the 
                   issuance of a new Warrant for the balance of _______ shares.
   
   
                                  Signature------------------------------------
   
   
                                  Print Name:----------------------------------
   
                                  Address:-------------------------------------
   
                                          -------------------------------------
   
   <PAGE>
                                      EXHIBIT B
                                          to
                                Stock Purchase Warrant
                                       between

                                                     
                                   (the "Investor")
                                         and
                           Progenics Pharmaceuticals, Inc.
                                   (the "Company")


               STOCK TRANSFER RESTRICTIONS AND RIGHTS OF FIRST REFUSAL


    1.   Restrictions on Voluntary Non-Sale Transfers.  Except for a proposed 
sale, the Investor (which term for the purpose of this Exhibit shall include 
each person who acquires Securities (as hereinafter defined) from the 
Investor) shall not transfer, pledge or otherwise dispose of any or all of 
the warrants (the "Warrants") granted to the Investor under the Loan 
Guarantee Agreement dated March 12, 1997 between the Company and Investor or 
any security acquired in exercise of or in exchange for the Warrants 
(collectively, the "Securities") which the Investor then owns to any person, 
firm, partnership, corporation, trust or other entity other than a Permitted 
Transferee or Advisory Client (as defined in Section 2), without the prior 
approval of the Board of Directors.  Any such transfer, pledge or other 
disposition shall be on such terms and conditions as the Board of Directors 
shall, in its sole discretion, approve, including, without limitation, the 
condition that the transferee enter into a restrictive agreement with the 
Company as to the sale, transfer, pledge or other disposition of the 
Securities on terms and conditions satisfactory to the Company.  As used 
herein the term "Permitted Transferee" means (i) any stockholder of the 
Company, (ii) a stockholder's spouse, sibling, spouse's sibling, child 
(natural or adopted), stepchild, grandchild, uncle, aunt, niece, nephew, 
parent, or grandparent, (iii) any trust for the sole benefit of one or more 
of the foregoing persons, (iv) a corporation the majority of whose voting 
securities of all classes is directly or indirectly owned by the Investor, 
(v) any non-corporate entity the majority of the beneficial interests of 
which is owned by the Investor, (vi) a corporation or non-corporate entity 
which owns, directly or indirectly, a majority of the voting securities of 
all classes of the Investor, or (vii) a corporation or non-corporate entity, 
the majority of whose securities or interests of all classes is directly or 
indirectly owned by the same corporate or non-corporate entity or by the same 
natural person as the Investor; provided that in each case such transferee, 
prior to and as a condition of such transfer, must agree in writing to be 
bound by all of the terms and conditions of this Agreement.

    2.   Sale of Securities; Right of First Refusal.  In the event the 
Investor proposes to sell any or all of the Securities (the "Offered Shares") 
to any person other than a Permitted Transferee or an Advisory Client the 
Investor shall first give written notice thereof to the Company (the 
"Notice") and shall offer to sell the Offered Shares to the Company.  The 
term "Advisory Client" shall mean a person with respect to which the Investor 
acts as an investment advisor and as to which the Investor has direct or 
indirect securities, commodities or futures trading discretion under an 
investment advisory contract.  The Notice shall specify the name of the 
person or persons to whom the Investor proposes to transfer the Offered 
Shares (or if no particular purchaser is identified, then the general class 
of persons to whom he proposes to transfer the Offered Shares), and a price 
per share which shall be the minimum price at which the Investor proposes to 
effect the transfer (the "Minimum Price").  The Notice shall contain an 
affirmation by the Investor that he or it has a reasonable expectation of 
being able to effect a transfer at the Minimum Price and to such person or 
persons (or class of persons) and shall recite the basis for such 
expectation.  The Notice shall offer to sell the Offered Shares to the 
Company, at the Minimum Price and on such other terms and conditions, if any, 
not less favorable to the Company as those proposed to be offered to such

                                         B-1
<PAGE>

other person or persons (or class of persons).  In the event all or any part 
of the consideration shall consist of other than cash the Minimum Price shall 
mean the fair value of such consideration, including the fair value of any 
promissory notes of the prospective purchaser (taking into account, among 
other matters, the terms of the notes and the creditworthiness of the 
prospective purchaser).

    The Company shall act upon the offer of the Investor by giving written 
notice (the "Company's Notice") to the Investor setting forth the Company's 
intention as to the Offered Shares.  The Company's Notice shall be given as 
soon as practicable after receipt of the Notice, and in all events within 
thirty (30) days after such receipt (the "Acceptance Period").  In the event 
the Company shall elect to purchase or acquire all of the Offered Shares, 
written notice to the Investor of such election to purchase or so acquire all 
of the Offered Shares shall, when taken in conjunction with the Notice, be 
deemed to constitute a valid and legally binding purchase and sale agreement. 
 The Company may assign in whole or in part its right to purchase the Offered 
Shares.

    If the Company fails to accept the Investor's offer to sell all of the 
Offered Shares, the Investor shall be free to proceed to sell all, but not 
less than all, of the Offered Shares to the person or persons (or class of 
persons) specified in the Notice at not less than the Minimum Price.  If the 
Investor fails to complete the proposed sale within a period of ninety (90) 
days after the earlier to occur of the date of rejection of the offer 
contained in the Notice or the expiration of the Acceptance Period, then, the 
Offered Shares shall once again be subject to the requirements of a prior 
offer pursuant to the provisions of this Agreement.

    The closing of a purchase of Offered Shares by the Company (or its 
assignee) shall take place at the principal executive offices of the Company 
on the thirtieth (30th) day following the expiration of the Acceptance Period 
(unless another time is mutually agreed upon), at which time the Investor 
shall deliver the stock certificate or certificates representing the Offered 
Shares so sold (duly endorsed or accompanied by a duly executed stock power 
or assignment to effect transfer of ownership to the purchaser or purchasers 
on the records of the Company together with evidence of the payment of any 
applicable transfer tax) against the Investor's receipt of payment of the 
Minimum Price in cash (by certified check, bank cashier's check or wire 
transfer); provided, however, if the Minimum Price consists in whole or in 
part of promissory notes, the Company shall have the option of giving 
promissory notes of like tenor or cash in an amount equal to the fair market 
value of such promissory notes.

    Notwithstanding the foregoing, in the event that the Company fails to 
accept the offer by the Investor to sell the Offered Shares and the Notice 
given by the Investor did not identify the specific person to whom the 
Investor proposed to sell the Offered Shares, the Investor shall not later 
than fifteen (15) days prior to the closing of the proposed transaction 
identify the specific proposed purchaser (the "Identified Purchaser") and 
provide such further information with respect to the Identified Purchaser as 
the Company may reasonably request.  The Offered Shares may not be sold to 
the Identified Purchaser if the Company gives written notice to the Investor 
not later than seven (7) days prior to the closing of the proposed 
transaction stating that the Company intends to purchase the Offered Shares 
for the price they are proposed to be sold to the Identified Purchaser and 
within no later than ten (10) days after the date of such written notice the 
Company (or its assignee) purchases the Offered Shares at the same price and 
on substantially the same or equivalent terms which the Identified Purchaser 
was to have purchased the Offered Shares; provided, however, that if the 
Company (or its assignee) does not so purchase the Offered Shares within such 
time period the Investor may proceed to consummate the proposed sale with the 
Identified Purchaser.

    A sale of all or any of the Securities to a Permitted Transferee or 
Advisory Client shall not be subject to the Right of First Refusal provided 
herein if prior to and as a condition of such sale such Permitted Transferee 
or Advisory Client agrees in writing to be bound by all of the terms and 
conditions of this Agreement.

                                         B-2
<PAGE>


    3.   Involuntary Disposition Other Than By Death.  In the event the 
Securities are subject to an involuntary disposition, including dispositions 
pursuant to a divorce or separation proceeding, or any other judicial 
proceeding, but excluding by reason of death of the Investor, the Company 
shall have the right to repurchase the Securities prior to such disposition.  
At least thirty (30) days prior to any such disposition the Company shall be 
given written notice thereof.  The purchase price for each share repurchased 
hereunder shall at any time be the equivalent per share price at which the 
Company then most recently sold stock to outside investors.  If the Board of 
Directors of the Company (with the Investor abstaining if he is then a member 
of the Board of Directors) in good faith determines that at the time of such 
repurchase the fair market value is substantially different than such most 
recent sales price, it may elect to have the fair market value of such 
repurchased shares determined by a firm of nationally known independent 
public accountants mutually agreeable to the Company and the Investor, in 
which event such fair market value will be the repurchase price.  In the 
event that the Investor believes that at the time of such repurchase the fair 
market value is substantially different than such most recent sales price, it 
may elect, at its sole cost and expense, to have the fair market value of 
such repurchased shares determined by a firm of nationally known independent 
public accountants mutually agreeable to the Company and the Investor, in 
which event such fair market value will be the repurchase price.  If the 
Company elects to purchase such shares it shall have the option of paying 
such purchase price in cash, or by a combination of cash and non-negotiable 
unsecured promissory note of the Company (the "Company Note").  The Company 
shall act upon the deemed offer under this section within ninety (90) days of 
the Company's receipt of written notice setting forth the existence of such 
an involuntary disposition event.

    The Company Note shall have the following terms:  it shall have a 
maturity of no more than three years; the principal amount thereof will be 
paid in equal annual installments; interest shall accrue on the unpaid 
principal amount of the Company Note at the rate of nine percent (9%) simple 
interest per annum (or such higher rate as may be required to avoid imputed 
interest under the Internal Revenue Code of 1986, as amended, or under 
regulations promulgated thereunder), payment of accrued interest shall be 
made when payments of principal are due; it shall be subject to prepayment at 
the Company's option without penalty in whole or in part at any time; it 
shall by its terms be subordinate to, and the holder of the Company Note by 
receiving the same shall be deemed to have subordinated payment thereof to, 
existing or future indebtedness to banks or other lending institutions; 
provided that so long as the Company shall not be in default with respect to 
said indebtedness, the holder of the Company Note shall be entitled to 
receive payments of the principal of and interest accrued upon the Company 
Note in accordance with its terms.

    4.   Dispositions By Reason Of Death.  In the event of death of the 
Investor the beneficiaries of the Investor's estate or others to whom any of 
the Securities are distributed shall take such Securities subject to the 
terms and conditions hereof and shall become a party to and shall be bound by 
the terms and conditions hereof. Notwithstanding the foregoing if the Board 
of Directors makes a good faith determination that the transfer of the 
Securities to a particular person as a result of the death of the Investor 
would not be in the best interest of the Company or its stockholders the 
transfer shall be deemed to be subject to the provisions of Section 3 and the 
Company may repurchase the Securities involved as provided therein.  For 
purposes of illustration and without limiting the discretion of the Board, 
the Board may deem it contrary to the best interests of the Company for any 
Securities to be sold to a competitor of the Company or a competitor of 
another company with which the Company is engaged in business.

    5.   Lock-Up Agreement.  The Investor agrees that the Investor and the 
Securities shall be bound by any "lock-up" or other agreement between the 
Company and any underwriter of securities of the Company which may be entered 
into in connection with a registered initial public offering of the Company's 
securities.

    6.   Transferees To Be Bound By Restrictions.  It shall be a condition of 
any sale, assignment, transfer, pledge or other disposition of Securities 
that the Investor obtain an agreement, in form and substance satisfactory to 
the Company, from any such person or persons, pursuant to which such person 
or persons agree to be bound by and comply with the provisions of this 
Agreement.

                                         B-3
<PAGE>


    7.   Transfers Void.  Any sale, assignment, transfer, pledge or other 
disposition of Securities which is not in accordance with the provisions of 
this Agreement shall be void and of no effect and shall not be recognized by 
the Company.

    8.   Restrictions On Stock Certificates.  Each certificate representing 
the Securities owned by the Investor (including certificates acquired after 
the date hereof) shall bear the following legend on the back thereof:

         "Transfer of shares represented by this Certificate is also subject to
         certain restrictions and repurchase rights set forth in a Stock 
         Purchase Warrant dated June 9, 1997 between this Company and the 
         holder of these shares."

    9.   Termination Of Restrictions.  The restrictions contained in this 
Agreement (other than Section 5 hereof) shall cease to apply upon the 
earliest to occur of (a) such time as the shares of stock subject to this 
Agreement are either listed on a national securities exchange or are quoted 
in the daily over-the-counter list published by The Nasdaq Market, or (b) 
such class of stock is registered pursuant to the provisions of Section 12(g) 
of the Securities Exchange Act of 1934, as amended, and is held of record by 
not less than five hundred (500) persons at the time such determination is 
made, or (c) the Company is the subject of a merger or consolidation in which 
the Company is not the surviving entity, or (d) substantially all of the 
assets of the Company are sold, or (e) on dissolution of the Company.  The 
restrictions contained in Section 5 shall terminate at such time as any such 
agreement referred to therein terminates.

    10.  Power of Attorney.  The Investor hereby irrevocably appoints the 
Chairman, CEO or President of the Company, as from time to time in office, as 
his attorney-in-fact, acting singly or jointly, to execute any and all stock 
powers and assignments necessary or useful to accomplish the rights conferred 
on the Company hereby.

                                         B-4
<PAGE>

 
    IN WITNESS WHEREOF, the parties have executed or caused to be executed 
this Exhibit B as of the date(s) set forth below.

                                               ----------------------------    
                                               INVESTOR'S NAME


Dated:---------------, 1997                    By:-------------------------    
                                                  Name:
                                                  Title (if applicable):


                                               PROGENICS PHARMACEUTICALS, INC.


Dated:---------------, 1997                    By:-------------------------    
                                               Paul J. Maddon, M.D., Ph.D.
                                               Chairman, CEO and President

 
                                      B-5


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