SUGEN INC
8-K, 1999-06-21
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
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                                       SECURITIES AND EXCHANGE COMMISSION
                                              WASHINGTON, DC 20549



                                                    FORM 8-K

                                                 CURRENT REPORT
                                     Pursuant to Section 13 or 15(d) of the
                                         Securities Exchange Act of 1934



                         Date of Report (Date of earliest event reported): June 15, 1999



                                                   SUGEN, INC.
                             (Exact name of registrant as specified in its charter)



            Delaware                                0-24814                              13-3629196
(State or other jurisdiction of              (Commission File No.)            (IRS Employer Identification No.)
         incorporation)


                                              230 East Grand Avenue
                                          South San Francisco, CA 94808
                              (Address of principal executive offices and zip code)


                       Registrant's telephone number, including area code: (650) 553-8300


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<PAGE>

Item 5.  Other Events.

On June 15, 1999, SUGEN, Inc., a Delaware  corporation (the "Company"),  entered
into an Agreement and Plan of Merger (the "Merger  Agreement")  with Pharmacia &
Upjohn,  Inc., a Delaware  corporation  ("Parent"),  and University  Acquisition
Corp., a Delaware  corporation  and wholly owned  subsidiary of Parent  ("Merger
Subsidiary").

Subject to the terms and conditions of the Merger  Agreement,  Merger Subsidiary
will be merged with and into the Company (the "Merger") at the effective time of
the Merger,  and the Company will become a wholly owned subsidiary of Parent. At
the effective time of the Merger,  the outstanding  shares of common stock, $.01
par value per share, of the Company ("Company Common Stock"),  other than shares
of Company Common Stock to be canceled in accordance with the Merger  Agreement,
will be converted into the right to receive that number of shares (the "Exchange
Ratio") of common stock,  par value $.01 per share,  of Parent  ("Parent  Common
Stock"), based on the average (rounded to the 1/10,000, or if there shall not be
a  nearest  1/10,000,  to the next  highest  1/10,000)  of the  volume  weighted
averages (rounded to the 1/10,000,  or if there shall not be a nearest 1/10,000,
to the next highest  1/10,000) of the trading  prices of Parent  Common Stock on
the New York Stock Exchange,  Inc. ("NYSE"),  as reported by Bloomberg Financial
Markets for each of the 20 NYSE trading days ending on and  including  the third
trading day  immediately  preceding the meeting of  stockholders  of the Company
called to vote on the Merger (the "Average Price"), determined as follows:

         (i)   if the  Average  Price is greater  than  $49.21875  and less than
         $60.15626,  then the Exchange  Ratio shall equal $31.00  divided by the
         Average Price;

         (ii)  if the Average Price is equal to or less than $49.21875, then the
         Exchange Ratio shall equal 0.62984; or

         (iii) if the Average Price is equal to or greater than $60.15625,  then
         the Exchange Ratio shall equal 0.51533.

In addition,  Parent will assume  outstanding  options  exercisable  for Company
Common Stock.

The  Merger is  intended  to be a  tax-free  reorganization  under the  Internal
Revenue  Code of 1986,  as amended,  and is intended  to be  accounted  for as a
pooling-of-interests.  The Merger is subject to approval by the  stockholders of
the Company, regulatory approvals and other customary closing conditions.

Also on June 15, 1999,  the Company  entered into a Stock Option  Agreement with
Parent (the "Stock Option  Agreement")  pursuant to which the Company granted an
option to Parent to purchase up to 3,372,255 shares of Company Common Stock at a
price of $31.00  per share upon the  occurrence  of  certain  events  related to
termination  of the Merger  Agreement.  In addition,  certain  affiliates of the
Company entered into voting agreements on June 15, 1999,  pursuant to which such
affiliates agreed to vote shares owned by them in favor of the Merger.

The foregoing  summaries of certain  principal terms of the Merger Agreement and
the Stock Option  Agreement  do not purport to be complete and are  qualified in
their  entirety  by  reference  to the  Merger  Agreement  and the Stock  Option
Agreement,  copies of which are attached  hereto as Exhibit 2.1 and Exhibit 2.2,
respectively, and are hereby incorporated by reference herein.

<PAGE>

A copy of the press release issued by Parent and the Company on June 15, 1999 is
attached hereto as Exhibit 99.1 and is hereby incorporated by reference herein.

A  registration  statement  relating to the Parent  Common Stock to be issued in
connection  with the Merger has not yet been filed with the SEC, nor has a proxy
statement  relating to a vote of the Company's  stockholders  on the Merger been
filed with the SEC. The Parent  Common Stock may not be offered,  nor may offers
to  acquire  such  stock be  accepted,  prior to the  time  such a  registration
statement becomes  effective.  This Report shall not constitute an offer to sell
or the  solicitation  of an offer to buy any  Parent  Common  Stock or any other
security,  and shall not constitute the solicitation of any vote with respect to
the Merger.

This Current Report on Form 8-K contains  forward-looking  statements within the
meaning of Section 27A of the  Securities  Act of 1933, as amended,  and Section
21E of the  Securities  Exchange Act of 1934,  as amended.  The  forward-looking
statements  contained  herein involve risks and  uncertainties,  including those
relating to the possible inability to complete the merger transaction  involving
the Company and Parent as scheduled,  if at all, and those  associated  with the
ability of the  combined  company to achieve  the  anticipated  benefits  of the
merger.  Actual  results  and  developments  may  differ  materially  from those
described or  incorporated  by reference  in this Report.  For more  information
about Parent and the Company and risks arising when  investing in Parent and the
Company, investors are directed to Parent's and the Company's most recent report
on Form 10-K and most  recent  report on Form 10-Q as filed with the  Securities
and Exchange Commission (the "SEC").

Item 7.  Financial Statements and Exhibits.

(a)      Financial statements of businesses acquired.

Not applicable.

(b)      Pro forma financial information.

Not applicable.

(c)      Exhibits

         2.1      Agreement  and Plan of  Merger,  dated June 15,  1999,  by and
                  among  Pharmacia  &  Upjohn,   Inc.,  a  Delaware  corporation
                  ("Parent"),   University   Acquisition   Corp.,   a   Delaware
                  corporation,  and SUGEN,  Inc.,  a Delaware  corporation  (the
                  "Company").

         2.2      Stock Option  Agreement,  dated June 15, 1999,  by and between
                  Parent and the Company.

         99.1     Joint Press Release of Parent and the Company, issued June 15,
                  1999.

<PAGE>

                                   SIGNATURES

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

                                  SUGEN, INC.


                                  /s/ James L. Knighton
                                  ----------------------------------------------
                                  By:  James L. Knighton
                                       Senior Vice President and Chief Financial
                                       Officer

Dated: June 17, 1999

<PAGE>

Exhibit
Number            Exhibit Description
- -------           -------------------

2.1               Agreement  and Plan of  Merger,  dated June 15,  1999,  by and
                  among  Pharmacia  &  Upjohn,   Inc.,  a  Delaware  corporation
                  ("Parent"),   University   Acquisition   Corp.,   a   Delaware
                  corporation  and  SUGEN,  Inc.,  a Delaware  corporation  (the
                  "Company").

2.2               Stock Option  Agreement,  dated June 15, 1999,  by and between
                  Parent and the Company.

99.1              Joint Press Release of Parent and the Company.




                                                                     EXHIBIT 2.1


                                                                  EXECUTION COPY







                          AGREEMENT AND PLAN OF MERGER


                                      among


                                  SUGEN, INC.,


                            PHARMACIA & UPJOHN, INC.


                                       and


                          UNIVERSITY ACQUISITION CORP.



                            Dated as of June 15, 1999



<PAGE>

                                Table of Contents
                                -----------------

Section                                                                     Page
- -------                                                                     ----

                                    ARTICLE I

                       The Merger; Closing; Effective Time

1.1.       The Merger..........................................................2
1.2.       Closing.............................................................2
1.3.       Effective Time......................................................3

                                   ARTICLE II

                          Certificate of Incorporation
                     and Bylaws of the Surviving Corporation

2.1.       The Certificate of Incorporation....................................3
2.2.       The Bylaws..........................................................3

                                   ARTICLE III

                             Officers and Directors
                          of the Surviving Corporation

3.1.       Directors...........................................................3
3.2.       Officers............................................................4

                                   ARTICLE IV

                     Effect of the Merger on Capital Stock;
                            Exchange of Certificates

4.1.       Effect on Capital Stock.............................................4
           (a) Merger Consideration............................................4
           (b) Cancellation of Excluded Shares.................................5
           (c) Merger Sub......................................................5
4.2.       Exchange of Certificates for Shares.................................6
           (a) Exchange Agent..................................................6
           (b) Exchange Procedures.............................................6
           (c) Distributions with Respect to Unexchanged Shares; Voting........7
           (d) Transfers.......................................................8
           (e) Fractional Shares...............................................8
           (f) Termination of Exchange Fund....................................9
           (g) Lost, Stolen or Destroyed Certificates..........................9
4.3.       Dissenters' Rights..................................................9

                                       -i-


<PAGE>


Section                                                                     Page
- -------                                                                     ----

4.4.       Adjustments to Prevent Dilution....................................10
4.5.       Treatment of Convertible Notes.....................................10

                                    ARTICLE V

                         Representations and Warranties

5.1.       Representations and Warranties of the Company......................10
           (a)  Organization, Good Standing and Qualification.................10
           (b)  Capital Structure.............................................12
           (c)  Corporate Authority; Approval and Fairness....................14
           (d)  Governmental Filings; No Violations...........................15
           (e)  Company Reports; Financial Statements.........................17
           (f)  Absence of Certain Changes....................................18
           (g)  Litigation and Liabilities....................................19
           (h)  Employee Benefits.............................................19
           (i)  Compliance....................................................22
           (j)  Antitakeover Statutes.........................................23
           (k)  Environmental Matters.........................................23
           (l)  Accounting and Tax Matters....................................25
           (m)  Taxation......................................................25
           (n)  Certain Regulatory Matters....................................27
           (o)  Intellectual Property.........................................29
           (p)  Product Registration Files....................................33
           (q)  Year 2000 Compliance..........................................34
           (r)  Labor Matters.................................................34
           (s)  Rights Agreement..............................................34
           (t)  Brokers and Finders...........................................35
           (u)  Supply Arrangements...........................................35
           (v)  Investigational Compounds.....................................35
5.2.       Representations and Warranties of Parent and Merger Sub............36
           (a) Capitalization of Merger Sub...................................36
           (b) Organization, Good Standing and Qualification..................36
           (c) Capital Structure..............................................37
           (d) Corporate Authority............................................38
           (e) Governmental Filings; No Violations............................39
           (f) Parent Reports; Financial Statements...........................40
           (g) Absence of Certain Changes.....................................41
           (h) Litigation and Liabilities.....................................41
           (i) Compliance.....................................................42
           (j) Accounting and Tax Matters.....................................42
           (k) Brokers and Finders............................................42

                                      -ii-


<PAGE>


Section                                                                     Page
- -------                                                                     ----


                                   ARTICLE VI

                                    Covenants

6.1.       Company Interim Operations.........................................43
6.2.       Conduct of Business of Parent......................................46
6.3.       Acquisition Proposals..............................................47
6.4.       Information Supplied...............................................50
6.5.       Stockholders Meeting...............................................50
6.6.       Filings; Other Actions; Notification...............................51
6.7.       Taxation and Accounting............................................55
6.8.       Access.............................................................57
6.9.       Affiliates.........................................................58
6.10.      Listing; De-registration...........................................59
6.11.      Publicity..........................................................59
6.12.      Benefits...........................................................60
           (a) Stock Options..................................................60
           (b) Employee Benefits..............................................61
6.13.      Expenses...........................................................61
6.14.      Indemnification; Directors' and Officers' Insurance................62
6.15.      Other Actions by the Company and Parent............................64
           (a) Rights  .......................................................64
           (b) Antitakeover Statutes..........................................64
6.16.      Convertible Notes and Warrants.....................................64
6.17.      Funding Mechanism..................................................64

                                   ARTICLE VII

                                   Conditions

7.1.       Conditions to Each Party's Obligation to Effect the Merger.........66
           (a) Stockholder Approval...........................................66
           (b) Regulatory Consents............................................66
           (c) Litigation.....................................................66
           (d) Registration Statement.........................................67
7.2.       Conditions to Obligations of Parent and Merger Sub.................67
           (a) Representations and Warranties.................................67
           (b) Performance of Obligations of the Company......................68
           (c) Regulatory Consents............................................68
           (d) Consents Under Agreements......................................68
           (e) Tax Opinion....................................................69

                                      -iii-


<PAGE>


Section                                                                     Page
- -------                                                                     ----

           (f) Rights Agreement...............................................69
           (g) Affiliates Letters.............................................69
           (h) Accountants' Letters...........................................69
7.3.       Conditions to Obligation of the Company............................69
           (a) Representations and Warranties.................................69
           (b) Performance of Obligations of Parent and Merger Sub............70
           (c) Regulatory Consents............................................70
           (d) Tax Opinion....................................................71
           (e) NYSE Listing...................................................71
           (f) Accountants' Letters...........................................71

                                  ARTICLE VIII

                                   Termination

8.1.       Termination by Mutual Consent......................................71
8.2.       Termination by Either Parent or the Company........................71
8.3.       Termination by the Company.........................................72
8.4.       Termination by Parent..............................................73
8.5.       Effect of Termination and Abandonment..............................74

                                   ARTICLE IX

                            Miscellaneous and General

9.1.       Survival...........................................................77
9.2.       Modification or Amendment..........................................77
9.3.       Waiver of Conditions...............................................77
9.4.       Counterparts.......................................................77
9.5.       GOVERNING LAW AND VENUE; WAIVER OF JURY TRIAL......................77
9.6.       Notices............................................................79
9.7.       Entire Agreement...................................................80
9.8.       No Third Party Beneficiaries.......................................80
9.9.       Obligations of Parent and of the Company...........................80
9.10.      Severability.......................................................81
9.11.      Specific Performance...............................................81
9.12.      Interpretation.....................................................81
9.13.      Assignment.........................................................81
9.14.      Captions...........................................................82


                                      -iv-


<PAGE>

                  AGREEMENT  AND  PLAN  OF  MERGER   (hereinafter   called  this
"Agreement"),  dated  as of  June  15,  1999,  among  SUGEN,  Inc.,  a  Delaware
corporation (the "Company"),  Pharmacia & Upjohn,  Inc., a Delaware  corporation
("Parent"),  and  University  Acquisition  Corp., a Delaware  corporation  and a
wholly  owned  subsidiary  of Parent  ("Merger  Sub," the Company and Merger Sub
sometimes  being  hereinafter  collectively  referred  to  as  the  "Constituent
Corporations").


                                    RECITALS

                  WHEREAS, the respective boards of directors of each of Parent,
Merger Sub and the Company have  approved the merger of Merger Sub with and into
the Company (the "Merger") and approved the Merger upon the terms and subject to
the conditions set forth in this Agreement and have  determined  that the Merger
and the other  transactions  contemplated  by this Agreement are fair to, and in
the best interest of, their respective stockholders;

                  WHEREAS, it is intended that, for federal income tax purposes,
the Merger shall  qualify as a  reorganization  under the  provisions of Section
368(a) of the  Internal  Revenue  Code of 1986,  as  amended,  and the rules and
regulations promulgated thereunder (the "Code");

                  WHEREAS,  for financial  accounting  purposes,  it is intended
that the Merger shall be accounted for as a "pooling-of-interests;"

                  WHEREAS,  contemporaneously with the execution and delivery of
this  Agreement,  the Company is entering  into a stock  option  agreement  with
Parent (the "Stock Option Agreement"), pursuant to which the Company has granted
to Parent an option to purchase  Shares (as defined in Section 4.1(a)) under the
terms and conditions set forth in the Stock Option Agreement; and

                  WHEREAS,  contemporaneously with the execution and delivery of
this Agreement,  certain holders of Shares are entering into a voting  agreement
with Parent (the  "Voting  Agreement")  pursuant to which such holders have made
certain agreements with respect to the Shares held by them.

                  NOW, THEREFORE,  in consideration of the premises,  and of the
representations,  warranties,  covenants and  agreements contained herein and in
the Stock Option Agreement, the parties hereto agree as follows:

<PAGE>

                                    ARTICLE I

                       The Merger; Closing; Effective Time

                  1.1. The Merger.  Upon the terms and subject to the conditions
set forth in this  Agreement,  at the Effective Time (as defined in Section 1.3)
Merger Sub shall be merged with and into the Company and the separate  corporate
existence  of  Merger  Sub  shall  thereupon  cease.  The  Company  shall be the
surviving  corporation in the Merger (sometimes  hereinafter  referred to as the
"Surviving  Corporation")  and shall  continue to be governed by the laws of the
State of Delaware,  and the separate corporate existence of the Company with all
its  rights,  privileges,  immunities,  powers  and  franchises  shall  continue
unaffected by the Merger, except as set forth in Articles II and III. The Merger
shall have the effects  specified in the Delaware  General  Corporation  Law, as
amended (the "DGCL").  Parent,  as the sole  stockholder  of Merger Sub,  hereby
approves the Merger and this Agreement.

                  1.2. Closing.  The closing of the Merger (the "Closing") shall
take place (i) at the  offices of  Sullivan & Cromwell,  125 Broad  Street,  New
York,  New York at 10:00 a.m. on the latest to occur of (A) the  business day on
which the condition set forth in Section  7.1(a) shall be satisfied or waived in
accordance with this Agreement and (B) the first business day following the date
on which the last to be satisfied or waived of the other conditions set forth in
Article  VII  (other  than  those  conditions  that by  their  nature  are to be
satisfied at the  Closing,  but subject to the  satisfaction  or waiver of those
conditions)  shall be satisfied or waived in accordance with this Agreement,  or
(ii) at such other  place and time  and/or on such other date as the Company and
Parent may agree in writing (the "Closing Date").

                  1.3.  Effective  Time.  As soon as  practicable  following the
Closing,  the Company will cause a Certificate  of Merger (the  "Certificate  of
Merger") to be executed,  acknowledged  and filed with the Secretary of State of
Delaware  as  provided  in  Section  251 of the DGCL.  The Merger  shall  become
effective  at the time when the  Certificate  of Merger has been duly filed with
the  Secretary  of State of the State of Delaware or, if agreed to by Parent and
the

                                       -2-


<PAGE>

Company,  such later time or date set forth in the  Certificate  of Merger  (the
"Effective Time").


                                   ARTICLE II

                          Certificate of Incorporation
                     and Bylaws of the Surviving Corporation

                  2.1. The  Certificate  of  Incorporation.  The  certificate of
incorporation of Merger Sub as in effect immediately prior to the Effective Time
shall be the certificate  of  incorporation  of the Surviving  Corporation  (the
"Charter"), except that Article FIRST of the Charter shall be amended to read in
its entirety as follows: "The name of the corporation is SUGEN, Inc."

                  2.2.   The  Bylaws.   The  bylaws  of  Merger  Sub  in  effect
immediately  prior to the  Effective  Time shall be the bylaws of the  Surviving
Corporation (the "Bylaws"),  until thereafter  amended as provided therein or by
applicable law.


                                   ARTICLE III

                             Officers and Directors
                          of the Surviving Corporation

                  3.1. Directors.  The directors of Merger Sub immediately prior
to the Effective Time shall, from and after the Effective Time, be the directors
of the Surviving  Corporation  until their  successors have been duly elected or
appointed and qualified or until their earlier death,  resignation or removal in
accordance with the Charter and Bylaws. Prior to the Effective Time, the Company
shall take all actions  necessary to obtain any  resignations  of its  directors
necessary to give effect to the provisions of this Section.

                  3.2. Officers.  The officers of the Company  immediately prior
to the Effective Time shall,  from and after the Effective Time, be the officers
of the Surviving  Corporation  until their  successors have been duly elected or
appointed and qualified or until their earlier death,  resignation or removal in
accordance with the Charter and Bylaws.


                                       -3-

<PAGE>

                                   ARTICLE IV

                     Effect of the Merger on Capital Stock;
                            Exchange of Certificates

                  4.1.  Effect on Capital  Stock.  At the  Effective  Time, as a
result of the Merger and without any action on the part of the Company,  Parent,
Merger Sub or any holder of any capital stock of the Company:

                  (a) Merger Consideration.  (i) Each share of common stock, par
value $0.01 per share,  of the Company  (each a "Share"  or,  collectively,  the
"Shares") issued and outstanding  immediately prior to the Effective Time (other
than  Shares  owned by Parent or any  direct or  indirect  Subsidiary  of Parent
(collectively,  the "Parent  Companies") or Shares that are owned by the Company
or any direct or indirect  Subsidiary  of the Company (and in each case not held
on  behalf of third  Parties)("Excluded  Shares"))  shall,  subject  to  Section
4.2(e), be converted into, and become exchangeable for the right to receive (the
"Merger  Consideration")  that number of shares (the "Exchange Ratio") of common
stock,  par  value  $0.01 per  share  (the  "Parent  Common  Stock"),  of Parent
determined by dividing $31.00 by the Average Price (as defined below); provided,
that (A) if the Average Price is equal to or less than  $49.21875,  the Exchange
Ratio shall be .62984;  and (B) if the Average Price is equal to or greater than
$60.15625, the Exchange Ratio shall be .51533. "Average Price" means the average
(rounded to the nearest  1/10,000,  or if there shall not be a nearest 1/10,000,
to the next highest  1/10,000) of the volume weighted  averages  (rounded to the
nearest  1/10,000,  or if there  shall  not be a nearest  1/10,000,  to the next
highest  1/10,000) of the trading  prices of Parent Common Stock on the New York
Stock Exchange, Inc. (the "NYSE") as reported by Bloomberg Financial Markets (or
such other  source as the parties  shall agree in writing)  for each of the NYSE
Trading Days; and (ii) "NYSE Trading Days" means the 20 NYSE trading days ending
on (and including) the third trading day immediately  preceding the Stockholders
Meeting (as defined in Section 6.5).

                  (ii) At the  Effective  Time,  all  Shares  shall no longer be
outstanding and shall be canceled and retired and shall cease to exist, and each
certificate (a  "Certificate")  formerly  representing any of such Shares (other
than Excluded Shares) shall thereafter represent only the right

                                       -4-


<PAGE>

to receive the Merger Consideration,  cash in lieu of fractional shares pursuant
to Section 4.2(e),  if any, and any distribution or dividend pursuant to Section
4.2(c).

                  (b)  Cancellation  of Excluded  Shares.  Each  Excluded  Share
issued and outstanding  immediately prior to the Effective Time shall, by virtue
of the Merger and without any action on the part of the holder thereof, cease to
be   outstanding,   shall  be  canceled  and  retired  without  payment  of  any
consideration therefor and shall cease to exist.

                  (c) Merger Sub. As of and following the Effective  Time,  each
share of Common  Stock,  par value  $.01 per  share,  of Merger  Sub  issued and
outstanding  immediately  prior to the Effective  Time shall  continue to remain
outstanding  and shall  constitute  one share of common  stock of the  Surviving
Corporation.

                  4.2. Exchange of Certificates for Shares.

                  (a) Exchange  Agent.  As of the Effective  Time,  Parent shall
deposit,  or shall cause to be  deposited,  with an exchange  agent  selected by
Parent and reasonably  acceptable to the Company (the "Exchange Agent"), for the
benefit of the holders of Shares, certificates representing the shares of Parent
Common Stock and, after the Effective Time, if applicable,  any cash,  dividends
or other  distributions  with respect to the Parent Common Stock to be issued or
paid  pursuant  to  Section  4.1(a)(ii)  (including  cash in lieu of  fractional
shares)  to be  exchanged  for  Shares  outstanding  immediately  prior  to  the
Effective Time upon due surrender of the  Certificates (or affidavits of loss in
lieu thereof)  pursuant to the provisions of this Article IV (such  certificates
for shares of Parent Common Stock,  together with the amount of any dividends or
other  distributions  payable  with  respect  thereto  and  any  cash in lieu of
fractional shares, being hereinafter referred to as the "Exchange Fund").

                  (b) Exchange  Procedures.  Promptly after the Effective  Time,
the Surviving  Corporation shall cause the Exchange Agent to mail to each holder
of record of Shares  (other  than  holders of  Excluded  Shares) (i) a letter of
transmittal  specifying  that delivery  shall be effected,  and risk of loss and
title to the Certificates shall pass, only upon delivery of the Certificates (or
affidavits of loss in

                                       -5-


<PAGE>

lieu thereof) to the Exchange Agent and (ii)  instructions  for use in effecting
the surrender of the Certificates in exchange for (A) certificates  representing
shares  of  Parent  Common  Stock  and  (B)  any  unpaid   dividends  and  other
distributions and cash in lieu of fractional shares.  Subject to Section 4.2(g),
upon surrender of a Certificate for  cancellation to the Exchange Agent together
with such letter of transmittal,  duly executed,  the holder of such Certificate
shall be entitled to receive in exchange therefor (x) a certificate representing
that number of whole shares of Parent  Common Stock that such holder is entitled
to receive  pursuant  to this  Article  IV and (y) a check in the amount  (after
giving  effect  to any  required  tax  withholdings)  of (A) any cash in lieu of
fractional  shares as provided in Section  4.2(e) plus (B) any unpaid  non-stock
dividends and any other  dividends or other  distributions  that such holder has
the right to receive  pursuant  to the  provisions  of this  Article IV, and the
Certificate so surrendered shall forthwith be canceled. No interest will be paid
or accrued on any amount payable upon due surrender of the Certificates.  In the
event of a  transfer  of  ownership of  Shares  that is not  registered  in  the
transfer records of the Company, a certificate representing the proper number of
shares of Parent  Common  Stock,  together  with a check for any cash to be paid
upon due surrender of the Certificate  and any other dividends or  distributions
in  respect  thereof,  may be issued  and/or  paid to such a  transferee  if the
Certificate  formerly  representing  such Shares is  presented  to the  Exchange
Agent,  accompanied  by all  documents  required  to  evidence  and effect  such
transfer and to evidence  that any  applicable  stock  transfer  taxes have been
paid. If any  certificate for shares of Parent Common Stock is to be issued in a
name other than that in which the Certificate  surrendered in exchange  therefor
is  registered,  it shall be a condition  of such  exchange  that the Person (as
defined  below)  requesting  such exchange shall pay any transfer or other taxes
required by reason of the issuance of  certificates  of shares of Parent  Common
Stock in a name other  than that of the  registered  holder of the   Certificate
surrendered,  or shall  establish to the  satisfaction of Parent or the Exchange
Agent that such tax has been paid or is not applicable.

                  For the purposes of this  Agreement,  the term "Person"  shall
mean any individual, corporation (including not-for-profit),  general or limited
partnership, limited liability company, joint venture, estate, trust,

                                       -6-


<PAGE>

association, organization, Governmental Entity (as defined in Section 5.1(d)) or
other entity of any kind or nature.

                  (c) Distributions with Respect to Unexchanged Shares;  Voting.
(i) All shares of Parent Common Stock to be issued  pursuant to the Merger shall
be deemed  issued  and  outstanding  as of the  Effective  Date and  whenever  a
dividend  or other  distribution  is declared by Parent in respect of the Parent
Common Stock,  the record date for which is at or after the Effective Time, that
declaration  shall include  dividends or other  distributions  in respect of all
shares issuable pursuant to this Agreement.  No dividends or other distributions
in  respect  of the  Parent  Common  Stock  shall be paid to any  holder  of any
unsurrendered  Certificate until such Certificate is surrendered for exchange in
accordance  with this  Article  IV.  Subject to the effect of  applicable  laws,
reasonably promptly following surrender of any such Certificate,  there shall be
issued  and/or  paid to the holder  certificates  representing  whole  shares of
Parent Common Stock issued in exchange  therefor,  without interest,  (A) at the
time of such surrender,  the dividends or other distributions with a record date
after the Effective Time  theretofore  payable with respect to such whole shares
of Parent Common Stock and not paid and (B) at the appropriate payment date, the
dividends  or other  distributions  payable with respect to such whole shares of
Parent  Common  Stock  with a record  date after the  Effective  Time but with a
payment date subsequent to surrender.

                  (ii) Holders of unsurrendered  Certificates  shall be entitled
to vote  after the  Effective  Time at any  meeting of Parent  stockholders  the
number of whole shares of Parent Common Stock represented by such  Certificates,
regardless of whether such holders have exchanged their Certificates.

                  (d)  Transfers.  After the Effective  Time,  there shall be no
transfers  on the stock  transfer  books of the  Company of the Shares that were
outstanding immediately prior to the Effective Time.

                  (e) Fractional Shares.  Notwithstanding any other provision of
this Agreement,  no fractional  shares of Parent Common Stock will be issued and
any holder of Shares  entitled to receive a  fractional  share of Parent  Common
Stock but for this Section  4.2(e) shall be entitled to receive,  as of the date
on which those holders entitled to receive  fractional shares are determined,  a
cash payment in

                                       -7-


<PAGE>


lieu of such fractional share,  without interest,  which payment shall represent
such  holder's  proportionate  interest in the net proceeds from the sale by the
Exchange  Agent on behalf of such holder of the aggregate  fractional  shares of
Parent Common Stock that such holder otherwise would be entitled to receive. Any
such sale shall be made by the Exchange Agent on the date on which those holders
entitled to receive fractional shares are determined.

                  (f)  Termination of Exchange Fund. Any portion of the Exchange
Fund  (including  the proceeds of any investments  thereof and any Parent Common
Stock) that  remains  unclaimed by the  stockholders  of the Company for 60 days
after the  Effective  Time  shall be paid to  Parent.  Any  stockholders  of the
Company who have not theretofore  complied with this Article IV shall thereafter
look only to Parent for payment of their  shares of Parent  Common Stock and any
cash,  dividends and other  distributions  in respect of the Parent Common Stock
payable  and/or  issuable  pursuant to Section  4.1 and Section  4.2(c) upon due
surrender of their Certificates (or affidavits of loss in lieu thereof), in each
case,  without any interest  thereon.  Notwithstanding  the  foregoing,  none of
Parent, the Surviving Corporation,  the Exchange Agent or any other Person shall
be liable to any former holder of Shares for any amount properly  delivered to a
public official pursuant to applicable  abandoned  property,  escheat or similar
laws.

                  (g) Lost, Stolen or Destroyed  Certificates.  In the event any
Certificate  shall have been lost,  stolen or  destroyed,  upon the making of an
affidavit  of that fact by the  Person  claiming  such  Certificate  to be lost,
stolen or destroyed and, if required by Parent,  the posting by such Person of a
bond in an amount  determined by Parent as indemnity  against any claim that may
be made against it with  respect to such  Certificate,  the Exchange  Agent will
issue in exchange for such lost,  stolen or destroyed  Certificate the shares of
Parent  Common  Stock and any cash  payable  and any unpaid  dividends  or other
distributions  in respect of Parent Common Stock pursuant to Section 4.2(c) upon
due surrender of and  deliverable  in respect of the Shares  represented by such
Certificate pursuant to this Agreement.

                  4.3. Dissenters' Rights. In accordance with Section 262 of the
DGCL, no appraisal  rights shall be available to holders of Shares in connection
with the Merger.

                                       -8-

<PAGE>

                  4.4. Adjustments to Prevent Dilution. In the event that (i) on
or after the date hereof and prior to the Effective Time the Company changes the
number of Shares or securities  convertible or exchangeable  into or exercisable
for  Shares  (except  as  specifically  contemplated  by or  permitted  by  this
Agreement or the Schedules hereto),  or (ii) Parent changes the number of shares
of  Parent  Common  Stock or  securities  convertible  or  exchangeable  into or
exercisable  for shares of Parent Common Stock issued and  outstanding  prior to
the Effective Time as a result of a  reclassification,  stock split (including a
reverse split) with a record date prior to the Effective Time, stock dividend or
distribution  with a record date prior to the Effective Time,  recapitalization,
merger,  subdivision,   issuer  tender  or  exchange  offer,  or  other  similar
transaction,  then,  in either  such  case,  the Merger  Consideration  shall be
equitably adjusted.

                  4.5. Treatment of Convertible Notes. The Convertible Notes and
Warrants  (as each such term is defined in Section  5.1(b))  shall be treated as
set forth in Section 6.16.


                                    ARTICLE V

                         Representations and Warranties

                  5.1.  Representations  and  Warranties  of  the  Company.  The
Company hereby represents and warrants to Parent and Merger Sub as follows:

                  (a)  Organization,  Good Standing  and  Qualification. Each of
the  Company and its  Subsidiaries  is a  corporation  duly  organized,  validly
existing and in good standing (where such concept is recognized)  under the laws
of its respective  jurisdiction of organization and has all requisite  corporate
or similar power and authority to own and operate its  properties and assets and
to carry on its business as presently  conducted and is qualified to do business
and is in good standing as a foreign  corporation  in each  jurisdiction  (where
such concept is  recognized)  where the ownership or operation of its properties
or conduct of its business requires such qualification, except where the failure
of any  of  the  Company's  Subsidiaries  to be so  qualified  or in  such  good
standing,  when taken together with all other such  failures,  is not reasonably
likely to have a

                                       -9-

<PAGE>

Company  Material  Adverse  Effect (as defined  below) or materially  impair the
ability  of the  Company,  the  Surviving  Corporation,  Parent  or any of their
respective  affiliates,  following  consummation  of the Merger,  to conduct any
material  business or  operations in any  jurisdiction  where they are now being
conducted.  The Company has made available to Parent a complete and correct copy
of the Company's and its Subsidiaries' certificates of incorporation  and bylaws
(or documents of a similar  scope for  corporations  organized in  jurisdictions
outside  the United  States),  each as amended to date.  The  Company's  and its
Subsidiaries' certificates of incorporation and bylaws (or similar documents) so
delivered are in full force and effect.  Schedule  5.1(a) contains a correct and
complete list of each jurisdiction  under the laws of which the Company and each
of its Subsidiaries is organized.

                  As  used in  this  Agreement,  (i)  "Subsidiary"  means,  with
respect to the  Company,  Parent or Merger  Sub, as the case may be, any entity,
whether  incorporated  or unincorporated,   of which  at least a majority of the
securities or ownership interests having by their terms ordinary voting power to
elect a majority of the board of directors or other persons  performing  similar
functions is directly or indirectly  owned or controlled by such party or by one
or more of its respective  Subsidiaries  or by such party and any one or more of
its respective  Subsidiaries,  (ii) "Company  Material Adverse Effect" means any
change in or effect on the business of the Company and its Subsidiaries that is,
or is  reasonably  likely to be,  materially  adverse  to the  business,  assets
(including intangible assets), liabilities (contingent or otherwise), prospects,
condition (financial or otherwise) of the Company and its Subsidiaries, taken as
a whole or the Projected Expenses; provided, however, that changes in or effects
on the  financial  condition  of the  Company and its  Subsidiaries,  taken as a
whole,  that result solely from expenditures by the Company and its Subsidiaries
which do not exceed the Projected  Expenses and expenses  incurred in connection
with the  transactions  contemplated  by this  Agreement  shall  not,  in and of
themselves,  constitute a Company  Material  Adverse  Effect,  and changes in or
effects on the  financial  condition  or results of operation of the Company and
its  Subsidiaries,  taken as a whole,  that result solely from  decreases in the
revenues of the Company and its  Subsidiaries  shall not, in and of  themselves,
constitute a Company Material Adverse Effect,  (iii) "Projected  Expenses" means
the aggregate projected expenses for the periods up to

                                      -10-


<PAGE>

and  including the Closing Date set forth in the budget of the Company set forth
in  Schedule  6.1(a)  (the  "Budget"),  and  (iv)  "due  investigation"  means a
commercially  reasonable  investigation  for a  company  engaged  in a  business
similar to that of the Company.

                  (b) Capital  Structure.  The  authorized  capital stock of the
Company  consists of 30,000,000  Shares,  of which only  16,951,307  Shares were
outstanding as of the close of business on June 14, 1999, and 20,000,000  shares
of Preferred Stock, par value $0.01 per share (the "Preferred Shares"), of which
none are  outstanding.  All of the outstanding  Shares have been duly authorized
and are validly issued, fully paid and nonassessable. Other than Shares reserved
for issuance  pursuant to the Stock Option Agreement,  the Company has no Shares
or Preferred Shares subject to issuance,  except (i) 300,000  Preferred  Shares,
designated Series A Junior  Participating  Preferred Stock,  subject to issuance
upon  exercise  of the  Rights  (the  "Rights")  issued  pursuant  to the Rights
Agreement,  dated as of August 1, 1995 (the  "Rights  Agreement"),  between  the
Company and The First National Bank of Boston,  as Rights Agent,  (ii) 1,681,839
Shares  subject  to  issuance  upon  conversion  of  the  Company's  12%  Senior
Convertible Notes due 2002 (the "12% Notes"),  (iii) 1,261,385 Shares subject to
issuance upon conversion of 12% Senior  Convertible  Notes (the "Warrant Notes")
issuable upon exercise of  outstanding  warrants to purchase  Warrant Notes (the
Warrants Notes,  collectively with the 12% Notes, the "Convertible Notes"), (iv)
1,806,776  Shares  reserved  for  issuance  in  connection  with the  payment of
interest on the Convertible  Notes (it being agreed that any such issuance shall
constitute a breach of this Agreement), (v) 675,798 Shares reserved for issuance
pursuant to the warrants  summarized in Schedule 5.1(b) (the  "Warrants"),  (vi)
3,187,244  shares  reserved for issuance  under the Company's  1992 Stock Option
Plan, as amended,  of which options to acquire  2,601,393 shares are outstanding
as of June 14, 1999,  (vii)  298,000  shares  reserved  for  issuance  under the
Company's 1994  Non-Employee  Directors'  Stock Option Plan, of which options to
acquire  165,000  shares are  outstanding  as of June 14, 1999,  (viii)  270,000
shares  reserved for issuance  under the Company's  Long-Term  Objectives  Stock
Option Plan for Senior  Management,  of which options to acquire  180,000 shares
are  outstanding as of June 14, 1999,  (xi) 206,422 shares reserved for issuance
under the Company's  Employee  Stock  Purchase Plan as of June 14, 1999, and (x)
50,000 Shares subject to issuance pursuant to

                                      -11-


<PAGE>

the Letter Agreement,  dated as of July 21, 1998, by and between the Company and
Stephen  Evans-Freke  (the  "Letter  Agreement").  Schedule  5.1(b) sets forth a
correct and complete list of each  outstanding  option to purchase  Shares under
the Stock  Plans,  as defined  below (each a "Company  Option"),  as of June 14,
1999,  including the holder, date of grant,  exercise price and number of Shares
subject  thereto.  All issued and  outstanding  shares of capital stock or other
securities of each of the Company's  Subsidiaries are duly  authorized,  validly
issued,  fully paid and  nonassessable  and,  except for  directors'  qualifying
shares,  owned by a direct or indirect  wholly owned  Subsidiary of the Company,
free  and  clear  of  any  lien,  pledge,  security  interest,  claim  or  other
encumbrance,  other than  immaterial  liens  which do not  affect the  Company's
right,  title and  interest in and to such shares or  securities.  Except as set
forth above or as disclosed in Schedule 5.1(b) or as  specifically  permitted by
this Agreement or the Schedules hereto,  there are no shares of capital stock of
the Company authorized,  issued or outstanding and except as set forth above and
as provided in the Stock Option  Agreement,  there are no preemptive  rights nor
any outstanding subscriptions, options, warrants, rights, convertible securities
or other  agreements or commitments of any character to which the Company or any
of its  Subsidiaries  is a party  or may be  bound  relating  to the  issued  or
unissued  capital  stock  or  other  securities  of  the  Company  or any of its
Subsidiaries.  Except for the  Warrants and the  Convertible  Notes as described
above,  the Company does not have  outstanding any bonds,  debentures,  notes or
other  obligations  the holders of which have the right to vote (or  convertible
into  or  exercisable  for  securities  having  the  right  to  vote)  with  the
stockholders  of the  Company  on any  matter  ("Voting  Debt").  Except for the
Company's  1992 Stock Option Plan,  1994  Non-Employee  Directors'  Stock Option
Plan,  Long-Term  Objectives Stock Option Plan for Senior  Management,  Employee
Stock  Purchase  Plan  and the  Letter  Agreement  (such  plans  and  agreements
collectively,  the "Stock Plans"),  at or after the Effective Time,  neither the
Surviving  Corporation nor Parent nor their respective  affiliates will have any
obligation to issue,  transfer or sell any shares or securities of the Surviving
Corporation,  Parent  or any of  their  respective  affiliates  pursuant  to any
Compensation  and  Benefit  Plan (as defined in Section  5.1(h)(i)).  No Shares,
Preferred Shares or other securities of the Company, the Surviving  Corporation,
Parent  or any of  their  respective  affiliates  will be  subject  to  issuance
pursuant to the Rights Agreement as a result of the

                                      -12-


<PAGE>

Merger or the other  transactions  contemplated  by  this  Agreement,  the Stock
Option  Agreement and the Voting  Agreement and no  Distribution  Date or Shares
Acquisition Date (as such terms are defined in the Rights  Agreement) shall have
occurred  as a result of the Merger or the other  transactions  contemplated  by
this Agreement, the Stock Option Agreement and the Voting Agreement.

                  (c)  Corporate  Authority;  Approval  and  Fairness.  (i)  The
Company  has all  requisite  corporate  power  and  authority  and has taken all
corporate  action  necessary  in order  to  execute,  deliver  and  perform  its
obligations  under  this  Agreement  and  the  Stock  Option  Agreement  and  to
consummate,  subject  only to  obtaining  the  adoption of this  Agreement  by a
majority  of the  shares  outstanding  as of the  record  date of the  Company's
stockholders  meeting (the "Company Requisite Vote"), the Merger. This Agreement
and the Stock Option Agreement are valid and binding  agreements of the Company,
enforceable against the Company in accordance with their respective terms.

                  (ii) The board of directors of the Company (A) has unanimously
approved this  Agreement  and the Stock Option  Agreement and the Merger and the
other transactions contemplated hereby and thereby and (B) has received the oral
opinion of its financial advisors,  Lehman Brothers Inc., to the effect that the
consideration  to be received by the holders of the Shares in the Merger is fair
to such holders from a financial point of view,  which opinion will be confirmed
in writing  promptly  after the date hereof (and a copy of such written  opinion
will be promptly  delivered to Parent).  It is agreed and  understood  that such
opinion is for the sole benefit of the Company's  board of directors and may not
be relied on by Parent or Merger Sub.

                  (d) Governmental  Filings;  No Violations.  (i) Other than any
filings  and/or  notices  required  (A)  pursuant to Section  1.3, (B) under the
Hart-Scott-Rodino  Antitrust  Improvements  Act of 1976,  as  amended  (the "HSR
Act"), the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and
the Securities  Act of 1933, as amended (the  "Securities  Act"),  (C) to comply
with state  securities  or "blue sky" laws,  and (D) such  filings or  consents,
registrations, approvals, permits or authorizations as may be required under the
competition or antitrust  laws of  jurisdictions  outside the United States,  no
notices or other filings are required to be made with, nor are any consents,

                                      -13-

<PAGE>

registrations,  approvals,  permits or authorizations required to be obtained by
the Company from, any governmental or regulatory authority,  agency, commission,
body or other governmental entity  ("Governmental  Entity"),  in connection with
the execution and delivery of this  Agreement and the Stock Option  Agreement by
the  Company  and the  consummation  by the  Company of the Merger and the other
transactions  contemplated hereby and thereby,  except those that the failure to
make or obtain are not,  individually or in the aggregate,  reasonably likely to
have  a  Company  Material  Adverse  Effect  or  prevent,  materially  delay  or
materially  impair the ability of the  Company to  consummate  the  transactions
contemplated  by this  Agreement  and the Stock Option  Agreement or  materially
impair the ability of the Company, the Surviving  Corporation,  Parent or any of
their respective  affiliates,  following  consummation of the Merger, to conduct
any material business or operations in any jurisdiction where they are now being
conducted.

                  (ii)  Except  as  set  forth  in  Schedule   5.1(d)(ii),   the
execution,  delivery  and  performance  of this  Agreement  and the Stock Option
Agreement  by the  Company  do not and will  not,  and the  consummation  by the
Company of the Merger and the other transactions contemplated hereby and thereby
will not,  constitute  or result in (A) a breach or  violation  of, or a default
under,  the  certificate  or bylaws of the Company or the  comparable  governing
instruments  of any of its  Subsidiaries,  (B) a breach  or  violation  of, or a
default under,  the  acceleration  of any obligations or the creation of a lien,
pledge,  security  interest or other encumbrance on the assets of the Company or
any of its Subsidiaries (with or without notice, lapse of time or both) pursuant
to,  any  agreement,  lease,  contract,  note,  mortgage,   indenture  or  other
obligation  ("Contracts") binding upon the Company or any of its Subsidiaries or
any Law (as  defined in  Section  5.1(i)) or  governmental  or  non-governmental
permit or license to which the Company or any of its Subsidiaries is subject, or
(C) any  change in the  rights  or  obligations  of any  party  under any of the
Contracts,  except,  in the case of clause  (B) or (C)  above,  for any  breach,
violation,  default,  acceleration,  creation or change that, individually or in
the  aggregate,  is not  reasonably  likely to have a Company  Material  Adverse
Effect,  prevent,  materially  delay or  materially  impair  the  ability of the
Company to consummate the  transactions  contemplated  by this Agreement and the
Stock Option  Agreement  or  materially  impair the ability of the Company,  the
Surviving Corporation, Parent or

                                      -14-

<PAGE>

any of their respective  affiliates,  following  consummation of the Merger,  to
conduct any material  business or operations in any jurisdiction  where they are
now being conducted.  Schedule 5.1(d)(ii) sets forth a correct and complete list
of all consents and waivers which are or may be required in connection  with the
consummation  of the  transactions  contemplated by this Agreement and the Stock
Option Agreement (whether or not subject to the exception set forth with respect
to clause (B) or (C) above)  under  Contracts to which the Company or any of its
Subsidiaries  is a party,  other than any consent or waiver (other than consents
or waivers  pursuant to Contracts  relating to  indebtedness,  securities or the
guarantee  thereof)  the  failure to obtain  which is not  reasonably  likely to
materially   affect  the  business  or   operations   of  the  Company  and  its
Subsidiaries.

                  (e) Company Reports; Financial Statements. The Company and, to
the extent  applicable,  each of its then or current  Subsidiaries  has made all
filings  required  to be  made  by  it  with  the  SEC  since  October  4,  1994
(collectively,  including any such reports filed  subsequent to the date hereof,
the "Company  Reports").  The Company has delivered or made  available to Parent
each registration  statement,  report, proxy statement or information  statement
filed  with the  Securities  and  Exchange  Commission  (the  "SEC") by it since
December 31, 1998 (the "Audit Date"),  including,  without  limitation,  (i) the
Company's  Annual Report on Form 10-K for the year ended December 31, 1998, (ii)
the Company's Quarterly Report for the quarter ended March 31, 1999, as amended,
(iii) the Company's  Proxy Statement filed on April 20, 1999, (iv) the Company's
Registration  Statement  on Form  S-3  filed  on  April  23,  1999,  and (v) the
Company's  Current  Report on Form 8-K filed on March 29, 1999,  all in the form
(including  exhibits,  annexes and any  amendments  thereto) filed with the SEC.
Except  as set forth in  Schedule  5.1(e),  as of their  respective  dates,  the
Company  Reports did not, and any Company  Reports filed with the SEC subsequent
to the date hereof will not,  contain any untrue statement of a material fact or
omit to state a material fact required to be stated therein or necessary to make
the statements made therein,  in light of the  circumstances  in which they were
made, not  misleading.  Each of the  consolidated  balance sheets included in or
incorporated by reference into the Company Reports  (including the related notes
and  schedules)  presents  fairly,  or  will  present  fairly,  in all  material
respects, the consolidated financial

                                      -15-

<PAGE>

position  of the  Company  and its  Subsidiaries  as of its date and each of the
consolidated  statements of income and of changes in financial position included
in or incorporated by reference into the Company Reports  (including any related
notes and schedules)  presents fairly,  or will present fairly,  in all material
respects, the results of operations,  retained earnings and changes in financial
position,  as the case  may be,  of the  Company  and its  Subsidiaries  for the
periods set forth therein (except as otherwise noted therein and subject, in the
case of unaudited  statements,  to notes and normal  year-end audit  adjustments
that will not be material in amount or effect),  in each case in accordance with
generally accepted  accounting  principles ("GAAP")  consistently applied during
the periods involved,  except, in the case of unaudited financial statements, as
permitted by SEC Form 10-Q, and except as may be noted  therein.  Other than the
Company  Reports  specifically  recited in clauses  (i) through (v) of the first
sentence of this  Section  5.1(e),  the Company has not, on or prior to the date
hereof,  filed any other definitive reports or statements with the SEC since the
Audit Date.

                  (f)  Absence of Certain  Changes.  Except as  disclosed in the
Company Reports filed prior to the date hereof or in Schedule 5.1(f),  since the
Audit Date the Company and its  Subsidiaries  have  conducted  their  respective
businesses  in all  material  respects  only in,  and have  not  engaged  in any
material  transaction  other than according to, the ordinary and usual course of
such  businesses  and  there  has not  been  (i)  any  change  in the  financial
condition,  properties,  business or results of operations of the Company or any
of its Subsidiaries or any occurrence or combination of occurrences of which the
Company has knowledge  that,  individually  or in the  aggregate,  has had or is
reasonably  likely to have a Company Material Adverse Effect;  (ii) any material
damage, destruction or other casualty loss with respect to any material asset or
property  owned,  leased  or  otherwise  used  by  the  Company  or  any  of its
Subsidiaries,  whether  or not  covered  by  insurance;  (iii) any  declaration,
setting  aside or payment of any dividend or other   distribution  in respect of
the capital  stock of the  Company;  or (iv) other than as set forth in Schedule
5.1(f),  any  change by the  Company  in  accounting  principles,  practices  or
methods.  Schedule  5.1(f)  contains a document  setting forth the name,  title,
salary and other  compensation  of each  employee  of the Company as of June 14,
1999. Since the date of such document, there has not been any increase in the

                                      -16-

<PAGE>

compensation  payable or that could become  payable by the Company or any of its
Subsidiaries to officers or key employees of the Company or its Subsidiaries, or
any amendment of any of the Stock Plans or Compensation and Benefit Plans.

                  (g)  Litigation  and  Liabilities.   Except  as  disclosed  in
Schedule  5.1(g) or as disclosed in the Company  Reports filed prior to the date
hereof, and except for matters which are not,  individually or in the aggregate,
reasonably  likely to have a Company  Material  Adverse  Effect  or  prevent  or
materially  delay or materially  impair the ability of the Company to consummate
the transactions contemplated by this Agreement and the Stock Option  Agreement,
there are no (i) civil, criminal,  administrative or regulatory actions,  suits,
claims, hearings,  investigations or proceedings pending or, to the knowledge of
the Company after due  investigation,  overtly threatened against the Company or
any of its  Subsidiaries  or (ii)  obligations  or  liabilities,  whether or not
accrued,  contingent  or otherwise  and whether or not required to be disclosed,
including those relating to matters  involving any Environmental Law (as defined
in Section 5.1(k)),  other than  liabilities  incurred in the ordinary course of
business by the Company and its Subsidiaries since the Audit Date.

                  (h) Employee Benefits.

                  (i) The Company  Reports  accurately  describe in all material
respects all  incentive,  bonus,  deferred  compensation,  pension,  retirement,
profit-sharing,  thrift, savings,  employee stock ownership,  stock bonus, stock
purchase,  restricted  stock,  stock  option and other  stock based  plans,  all
employment  or severance  agreements,  plans,  policies or  arrangements,  other
employee  benefit  plans and any  applicable  "change  of  control"  or  similar
provisions in any plan, agreement, policy or arrangement which covers current or
former  employees of the Company and its  subsidiaries  (the  "Compensation  and
Benefit Plans"). The Compensation and Benefit Plans and all other benefit plans,
agreements,  policies or arrangements  covering  current or former  employees or
directors of the Company and its Subsidiaries (the "Employees"),  including, but
not limited to,  "employee  benefit plans" within the meaning of Section 3(3) of
the Employee  Retirement Income Security Act of 1974, as amended ("ERISA"),  are
listed in Schedule 5.1(h)(i). True and complete copies of all Compensation and

                                      -17-

<PAGE>

Benefit  Plans  and  such  other   benefit   plans,   agreements,   policies  or
arrangements,  including,  but to  limited  to,  any  trust  instruments  and/or
insurance  contracts,  if any,  forming a part of any such plans and agreements,
and all amendments thereto have been provided or made available to Parent.

                  (ii) All employee  benefit  plans,  other than  "multiemployer
plans"  within the meaning of Sections  3(37) of ERISA,  covering  Employees and
maintained in the United States (the  "Plans"),  to the extent subject to ERISA,
are in  substantial  compliance  with  ERISA.  Each Plan  which is an  "employee
pension  benefit  plan"  within the meaning of Section  3(2) of ERISA  ("Pension
Plan")  and  which is  intended  to be  qualified  under  Section  401(a) of the
Internal Revenue Code of 1986, as amended (the "Code"), has received a favorable
determination  letter from the Internal Revenue Service,  and the Company is not
aware of any circumstances  likely to result in revocation of any such favorable
determination  letter.  There is no material pending or, to the knowledge of the
Company after due investigation,  threatened,  litigation relating to the Plans.
Neither  the Company nor any of its  Subsidiaries  has engaged in a  transaction
with respect to any Plan that,  assuming the taxable period of such  transaction
expired  as of  the  date  hereof,  could  subject  the  Company  or  any of its
Subsidiaries  to a tax or penalty  imposed by either Section 4975 of the Code or
Section 502(i) of ERISA in an amount which would be material.

                  (iii) No liability  under Subtitle C or D of Title IV of ERISA
has been or is expected to be incurred by the Company or any of its Subsidiaries
with respect to any ongoing, frozen or terminated "single-employer plan," within
the meaning of Section 4001(a)(15) of ERISA, currently or formerly maintained by
any of them, or the  single-employer  plan of any entity which is considered one
employer with the Company under Section 4001 of ERISA or Section 414 of the Code
(an "ERISA Affiliate").  The Company and its  Subsidiaries have not incurred and
do not expect to incur any withdrawal  liability with respect to a multiemployer
plan under  Subtitle  E of Title IV of ERISA  (regardless  of  whether  based on
contributions of an ERISA Affiliate).  No notice of a "reportable event," within
the meaning of Section 4043 of ERISA for which the 30-day reporting  requirement
has not been waived, has been required to be filed for any Pension

                                      -18-

<PAGE>

Plan or by any ERISA  Affiliate  within the 12-month  period  ending on the date
hereof.

                  (iv) All contributions  required to be made under the terms of
any Plan have been timely made or accrued on the Company's financial statements.
Neither any Pension Plan nor any single-employer  plan of an ERISA Affiliate has
an "accumulated  funding deficiency"  (whether or not waived) within the meaning
of Section 412 of the Code or Section 302 of ERISA and no ERISA Affiliate has an
outstanding funding waiver.  Neither the Company nor any of its Subsidiaries has
provided,  or is  required to  provide,  security to any Pension  Plan or to any
single-employer plan of an ERISA Affiliate pursuant to Section 401(a)(29) of the
Code.

                  (v) Under each Pension Plan which  is a single-employer  plan,
as of the last day of the most recent plan year ended prior to the date  hereof,
the actuarially  determined present value of all "benefit  liabilities,"  within
the meaning of Section  4001(a)(16)  of ERISA (as determined on the basis of the
actuarial  assumptions  contained  in the Pension  Plan's most recent  actuarial
valuation),  did not exceed the then current value of the assets of such Pension
Plan, and there has been no material  change in the financial  condition of such
Pension  Plan since the last day of the most  recent plan year.  The  withdrawal
liability  of the  Company  and its  Subsidiaries  under each  Compensation  and
Benefit Plan which is a  multiemployer  plan within the meaning of Section 3(37)
of ERISA to which  the  Company,  its  Subsidiaries  or an ERISA  Affiliate  has
contributed  during  the  preceding  12  months,  determined  as if a  "complete
withdrawal," within the meaning of Section 4203 of ERISA, had occurred as of the
date hereof, does not exceed $100,000.

                  (vi) Neither the Company nor any of its  Subsidiaries  has any
obligations  for retiree health and life benefits under any Plan,  except as set
forth on  Schedule  5.1(h)(vi).  The  Company or its  Subsidiaries  may amend or
terminate any such Plan at any time without incurring any liability thereunder.

                  (vii)  Except  as  set  forth  on  Schedule  5.1(h)(vii),  the
consummation  of the  transactions  contemplated  by this Agreement will not (x)
entitle any Employees to severance  pay, (y)  accelerate  the time of payment or
vesting or trigger any payment or funding

                                      -19-

<PAGE>

(through a grantor  trust or  otherwise)  of  compensation  or  benefits  under,
increase the amount  payable or trigger any other material  obligation  pursuant
to, any of the  Compensation  and Benefit Plans or (z) result in payments  under
any of the Plans which would not be deductible  under Section  162(m) or Section
280G of the Code.

                  (viii) All Compensation  and Benefit Plans maintained  outside
of the United States comply in all material  respects with applicable local law.
The Company and its  Subsidiaries  have no material  unfunded  liabilities  with
respect to any such Compensation and Benefit Plan.

                  (i)  Compliance.  Except  as set  forth  in  Schedule  5.1(i),
neither the Company nor any of its  Subsidiaries  is in default or violation of,
(i) any law, ordinance,  rule, regulation,  order, judgment, decree, arbitration
award,  license  or permit of any  Governmental  Entity  (collectively,  "Laws")
applicable to the Company or any of its  Subsidiaries  or by which its or any of
their respective properties are bound, or (ii) any Contract to which the Company
or any of its  Subsidiaries  is a party or by which  the  Company  or any of its
Subsidiaries or its or any of their respective properties are bound or affected,
except  for  any  such  defaults  or  violations  that,  individually  or in the
aggregate,  are not reasonably likely to have a Company Material Adverse Effect,
or prevent or materially delay the  transactions  contemplated by this Agreement
or  materially  impair the ability of the Company,  the  Surviving  Corporation,
Parent or any of their  respective  affiliates,  following  consummation  of the
Merger, to conduct any material business or operations in any jurisdiction where
they  are now  being  conducted.  To the  knowledge  of the  Company  after  due
investigation,  no material  change is required in the  Company's  or any of its
Subsidiaries'  processes,  properties  or  procedures  in order to comply in all
material  respects with any Laws, and the Company has not received any notice or
overt  communication of any material  noncompliance  with any such Laws that has
not been cured.

                  (j)  Antitakeover  Statutes.  The  board of  directors  of the
Company has taken all necessary action to approve the transactions  contemplated
by this Agreement, the Stock Option Agreement and the Voting Agreement such that
the  restrictions  under  Section  203 of the  DGCL  shall  not  apply  to  such
transactions.  No "fair price,"  "moratorium,"  "control share  acquisition"  or
other similar antitakeover

                                      -20-


<PAGE>

statute or regulation  (each,  an  "Antitakeover  Statute") is applicable to the
Company, the Shares, the Merger, this Agreement, the Stock Option Agreement, the
Voting Agreement or the other transactions  contemplated by this Agreement,  the
Stock Option Agreement or the Voting Agreement.

                  (k) Environmental Matters.  Except as disclosed in the Company
Reports filed with the SEC prior to the date hereof or in Schedule  5.1(k),  (i)
the Company and its Subsidiaries  have complied in all material  respects at all
relevant times with all applicable  Environmental Laws; (ii) to the knowledge of
the Company, after due investigation, no property currently or formerly owned or
operated  by  the  Company  or  any  of  its  Subsidiaries   (including   soils,
groundwater, surface water, buildings or other structures) has been contaminated
with any Hazardous Substance;  (iii) to the knowledge of the Company,  after due
investigation, neither the Company nor any of its Subsidiaries is subject to any
liability for Hazardous  Substance  disposal or contamination on any third party
property; (iv) to the knowledge of the Company, after due investigation, neither
the Company nor any of its  Subsidiaries is subject to liability for any release
or threat of release of any Hazardous Substance; (v) neither the Company nor any
of its Subsidiaries has received any notice,  demand,  letter,  claim or request
for  information  indicating  that  it  may be in  violation  of or  subject  to
liability under any  Environmental  Law; (vi) neither the Company nor any of its
Subsidiaries is subject to any order,  decree,  injunction or other  arrangement
with any Governmental  Entity or any indemnity or other agreement with any third
party relating to liability under any Environmental  Law; (vii) to the knowledge
of the Company,  after due investigation,  none of the properties of the Company
or  any  of  its   Subsidiaries   contain   any   underground   storage   tanks,
asbestos-containing  material,  lead  products,  or  polychlorinated  biphenyls;
(viii) to the knowledge of the Company,  after due  investigation,  there are no
other  circumstances  or  conditions   involving  the  Company  or  any  of  its
Subsidiaries  that  could  reasonably  be  expected  to  result  in any  claims,
liability,  investigations,  costs or  restrictions  on the  ownership,  use, or
transfer of any property in connection with any Environmental  Law; and (ix) the
Company has delivered or made  available to Parent  copies of all  environmental
reports, studies, assessments, sampling data and other environmental information
in its possession relating to the Company or any of its

                                      -21-

<PAGE>

Subsidiaries or any of their current or former properties or operations.

                  "Environmental  Law"  means any  federal,  state or local law,
regulation,  order,  decree,  permit,   authorization,   common  law  or  agency
requirement relating to (A) the protection,  investigation or restoration of the
environment,  health,  safety,  or natural  resources,  (B) the  handling,  use,
presence,  disposal, release or threatened release of any Hazardous Substance or
(C)  noise,   odor,  indoor  air,  employee   exposure,   wetlands,   pollution,
contamination or any injury or threat of injury to persons or property  relating
to any Hazardous Substance.

                  "Hazardous  Substance" means any substance that is (A) listed,
classified  or regulated  pursuant to any  Environmental  Law; (B) any petroleum
product or by-product,  asbestos-containing  material,  lead-containing paint or
plumbing,  polychlorinated biphenyls, radioactive materials or radon; or (C) any
other  substance  which  may  be  the  subject  of  regulatory   action  by  any
Governmental Authority in connection with any Environmental Law.

                  (l)  Accounting  and Tax Matters.  As of the date hereof,  the
Company  does not have any  knowledge  of any fact or  circumstance  that  would
prevent the Company from being a "poolable entity" for purposes of Opinion 16 of
the Accounting Principles Board or prevent the Merger and the other transactions
contemplated by this Agreement from qualifying as a "reorganization"  within the
meaning of Section 368(a) of the Code.

                  (m)  Taxation.  (a) The Company and each of its  Subsidiaries,
and any  consolidated,  combined or unitary  group for tax purposes of which the
Company or any of its Subsidiaries is or has been a member, has timely filed all
Tax Returns  required to be filed by it in the manner  provided by law. All such
Tax Returns are true, correct and complete in all material respects. The Company
and each of its  Subsidiaries  have  timely paid all Taxes due or required to be
withheld  from amounts  owing to any  employee,  creditor or third party or have
provided adequate reserves in their financial statements for any Taxes that have
not been paid,  whether or not shown as being due on any Tax Returns.  Except as
has been  disclosed  to Parent in Schedule  5.1(m):  (i) no  material  claim for
unpaid Taxes has become a lien or  encumbrance  of any kind against the property
of the Company

                                      -22-


<PAGE>

or any of its  Subsidiaries  or is being asserted  against the Company or any of
its Subsidiaries; (ii) no audit, examination,  investigation or other proceeding
in  respect  of  Taxes  is  pending,  threatened  or  being  conducted  by a Tax
authority;  (iii) no material  issues have been  raised by the  relevant  taxing
authority in  connection  with any  examination  of the Tax Returns filed by the
Company  and its  Subsidiaries;  (iv) no  extension  or waiver of the statute of
limitations  on the  assessment  of any Taxes has been granted by the Company or
any of its Subsidiaries and is currently in effect;  (v) neither the Company nor
any of its Subsidiaries is a party to, is bound by, or has any obligation under,
or  potential  liability  with  regards  to,  any  Tax  sharing  agreement,  Tax
indemnification  agreement or similar contract or arrangement;  (vi) no power of
attorney  has been  granted  by or with  respect  to the  Company  or any of its
Subsidiaries  with respect to any matter  relating to Taxes;  (vii)  neither the
Company nor any of its Subsidiaries is a party to any agreement,  plan, contract
or arrangement that would result, separately or in the aggregate, in the payment
of any "excess  parachute  payments"  within the meaning of Section  280G of the
Code;  (viii) neither the Company nor any of its  Subsidiaries  has any deferred
intercompany  gain  or loss  arising  as a  result  of a  deferred  intercompany
transaction  within the meaning of Treasury  Regulation  Section  1.1502-13  (or
similar provision under state, local or foreign law) or any excess loss accounts
within the meaning of Treasury Regulation Section 1.1502-19; (ix) the Company is
not and has not been a United  States  real  property  holding  corporation  (as
defined in Section 897(c)(2) of the Code) during the applicable period specified
in Section  897(c)(1)(ii)  of the Code;  (x)  neither the Company nor any of its
Subsidiaries  has been the subject to a Tax ruling that has  continuing  effect;
and (xi) neither the Company nor any of its  Subsidiaries has agreed to include,
or is required to include,  in income any adjustment under either Section 481(a)
or 482 of the Code (or an analogous provision of state, local or foreign law) by
reason of a change in accounting method or otherwise.

                  (b) Except as disclosed in Schedule 5.1(m),  as of the date of
this Agreement,  to the knowledge of the Company after due investigation,  there
are no facts or  circumstances  that have materially  adversely  affected or are
reasonably  likely to materially  adversely affect the ability of the Company or
its Subsidiaries to obtain the cantonal and Swiss federal tax benefits described
in the September

                                      -23-

<PAGE>


1998  ruling  of  the  Canton  of  Schaffhausen,   the  corresponding   Business
Development Agreement, and the March 1999 ruling of the Swiss Federal Office for
Economy and Labor, respectively.

                  "Taxes" means any taxes of any kind, including but not limited
to those on or measured by or referred to as income,  gross  receipts,  capital,
sales, use, ad valorem, franchise,  profits, license,  withholding,  employment,
payroll, premium, value added, property or windfall profits taxes, environmental
transfer taxes, customs,  duties or similar fees,  assessments or charges of any
kind whatsoever,  together with any interest and any penalties, additions to tax
or  additional  amounts  imposed  by any  governmental  authority,  domestic  or
foreign.

                  "Tax Return" means any return, report or statement required to
be filed with any governmental authority with respect to Taxes.

                  (n) Certain Regulatory Matters. (i) Schedule 5.1(n) sets forth
a complete and accurate list for the last five years, of (A) all Warning Letters
(as defined below), Section 305 notices and similar letters or notices issued by
the Food and Drug Administration  (the "FDA") or any other governmental  entity,
domestic or foreign,  that is concerned  with the quality,  identity,  strength,
purity,  safety,  efficacy or manufacturing of the  pharmaceutical  compounds or
products  tested  or  sold  by  the  Company  or  its  Subsidiaries   (any  such
governmental entity, a "Pharmaceutical Regulatory Agency") to the Company or any
of its  Subsidiaries;  (B)  all  United  States  Pharmacopoeia  product  problem
reporting program  complaints or reports,  MedWatch form FDA-3500A,  FDA-1639 or
Form CIMOS I filed by the Company or any of its  Subsidiaries,  which complaints
or reports pertain to any incident  involving  death or serious injury,  and for
which incident  there has been (I) a notice or follow-up  inquiry to the Company
or any of its Subsidiaries by the FDA, (II) a litigation or arbitration claim or
cause of action  commenced,  or (III) a notice to any  insurance  carrier of the
Company or any of its Subsidiaries tendering the defense or giving any notice of
a possible  or actual  claim  against the  Company or such  subsidiary;  (C) all
product recalls conducted by or issued to the Company or any of its Subsidiaries
and any  requests  from the FDA or any other  Pharmaceutical  Regulatory  Agency
requesting the Company or any of its Subsidiaries to cease to investigate,

                                      -24-

<PAGE>

test or market any compound or product;  (D) any civil penalty  actions begun by
the FDA or any other Pharmaceutical Regulatory Agency against the Company or any
of its  Subsidiaries  and all consent decrees and all documents  relating to the
negotiation  of and  compliance  with such consent decree issued with respect to
the Company or any of its Subsidiaries; and (E) any other written communications
between the Company or any of its Subsidiaries,  on the one hand, and the FDA or
any other  Pharmaceutical  Regulatory  Agency on the  other  hand that  describe
matters  that could have a material  adverse  effect on the  projected  sales or
revenues attributable to any compound, product or product line of the Company or
its  Subsidiaries or discuss material issues  concerning the quality,  identity,
strength,  purity,  safety or efficacy of any such compound,  product or product
line. The Company has made available to Parent copies of all documents  referred
to in Schedule 5.1(n), as well as copies of all complaints and other information
required to be maintained by the Company  pursuant to the United States  Federal
Food, Drug and Cosmetic Act and Comprehensive  Drug Abuse Prevention and Control
Act of 1970 and the  corresponding  laws of jurisdictions  other than the United
States.  For purposes of this  subparagraph (i), "Warning Letter" means a letter
characterized  by the FDA or any  other  Pharmaceutical  Regulatory  Agency as a
warning  letter,  a notice of adverse  finding or a similar  letter or report in
which FDA or any other  Pharmaceutical  Regulatory  Agency expresses the opinion
that violations of law have occurred.

                  (ii) With such  exceptions as are not material with respect to
(x) any of compounds SU101, SU5271,  SU5416 or SU6668 or (y) the other compounds
and products of the Company and its Subsidiaries, taken as a whole and except as
set forth in Schedule  5.1(n),  (A) the Company (or, if  applicable,  one of its
Subsidiaries)   has   obtained   all   consents,   approvals,    certifications,
authorizations  and permits of, and has made all filings with, or  notifications
to, all Pharmaceutical  Regulatory Agencies pursuant to applicable  requirements
of all FDA regulations and consent decrees, and all applicable state and foreign
laws, and regulations applicable to the Company or any of its Subsidiaries;  (B)
all representations made by the Company or any of its Subsidiaries in connection
with any such  consents,  approvals,  certifications,  authorizations,  permits,
filings and notifications  were true and correct in all material respects at the
time such  representations and warranties were made, and the Company's compounds
and

                                      -25-

<PAGE>

products,  and the  compounds  and products of its  Subsidiaries,  substantially
comply with,  and perform in accordance  with the  specifications  described in,
such representations;  (C) the Company and its Subsidiaries and their respective
products and all of the facilities and entities which manufacture such compounds
and products,  are in  substantial  compliance  with all  applicable  FDA rules,
regulations  and consent  decrees,  and all  applicable  state and foreign laws,
rules and  regulations  (including  Good  Manufacturing  Practices)  relating to
pharmaceutical  manufacturers  and  distributors or otherwise  applicable to the
Company's or its  Subsidiaries'  business;  and (D) the Company has no reason to
believe  that any of the  consents,  approvals,  authorizations,  registrations,
certifications,  permits,  filings  or  notifications  that  it or  any  of  its
Subsidiaries  has received or made to operate their  respective  businesses have
been or are being revoked or challenged.

                  (o) Intellectual Property.

                  (i) Set forth in Schedule 5.1(o)(i) is a complete list of each
of the following items (1) all patents and applications therefor,  registrations
of  trademarks  (including  service  marks)  and  applications   therefor,   and
registrations  of  copyrights  and  applications  therefor that are owned by the
Company or any of its  Subsidiaries  or  licensed  to the  Company or any of its
Subsidiaries   (collectively,   the  "Company  Owned  IP"),  (2)  all  licenses,
agreements  and  contracts  relating to the Company  Intellectual  Property  (as
defined in Section  5.1(o)(ii) of this Agreement)  pursuant to which the Company
or any of its Subsidiaries are entitled to use any Company Intellectual Property
owned by any third party (the "Third  Party  Licenses")  and (3) all  agreements
under which the Company or any of its  Subsidiaries  has granted any third party
the right to use any Company  Intellectual  Property,  including  the  unexpired
material transfer agreements.

                  (ii) Except to the extent  identified  in Schedule 5.1 (o)(ii)
and except for any failures of this  representation  and warranty to be true and
accurate that arise from instances  involving the infringement by the Company or
its  Subsidiaries  on  the  intellectual   property  rights  of  others  or  the
infringement  by others on  intellectual  property  rights of the Company or its
Subsidiaries of which, in either such case, the Company does

                                      -26-

<PAGE>

not have any knowledge after due investigation, the Company, or its Subsidiaries
where expressly indicated,  is the owner of, or is licensed to use, or otherwise
possesses legally enforceable rights in, all intellectual  property,  including,
without  limitation,   all  patents  and  patent   applications,   supplementary
protection   certificates  and  patent  extensions,   trademarks  and  trademark
applications,  service mark and service mark  registrations,  logos,  commercial
symbols,  business name  registrations,  trade names,  copyrights  and copyright
registrations,   computer  software,  mask  works  and  mask  work  registration
applications,  industrial  designs and  applications  for  registration  of such
industrial designs, including,  without limitation, any and all applications for
renewal,  extensions,  reexaminations  and  reissues  of any  of  the  foregoing
intellectual property rights where applicable, inventions, biological materials,
trade  secrets,  formulae,  know-how,  technical  information,   research  data,
research  raw  data,  laboratory  notebooks,  procedures,  designs,  proprietary
technology and  information  held or used in the business of the Company and its
Subsidiaries (hereinafter the "Company Intellectual Property").

                  (iii) Except to the extent identified in Schedule 5.1(o)(iii),
the Company and its Subsidiaries are the sole legal and beneficial owners of all
the Company Intellectual  Property (except for the Company Intellectual Property
that  is  the  subject  of  any  Third  Party  Licenses)  and  all  the  Company
Intellectual Property is valid and subsisting.

                  (iv) The Company has not entered into any agreements, licenses
or  created  any  mortgages,   liens,  security  interests,   leases,   pledges,
encumbrances,  equities, claims, charges, options, restrictions, rights of first
refusal,  title retention  agreements or other  exceptions to title which affect
the Company  Intellectual  Property or restrict the use by the Company or any of
its  Subsidiaries  of the Company  Intellectual  Property in any way,  except as
provided in agreements  and  instruments  disclosed in Schedule  5.1(o)(ii)  and
furnished to Parent prior to the date of this Agreement.

                  (v) Except as listed in Schedule  5.1(o)(v),  to the knowledge
of the Company after due investigation,  the Company and its Subsidiaries are in
compliance  in all  material  respects  with the Third Party  Licenses  that are
material to the conduct of the business of the Company.

                                      -27-

<PAGE>

                  (vi) The Company and its Subsidiaries are not, and will not be
as a result of the execution,  delivery or performance  of this  Agreement,  the
Stock Option Agreement or the Voting Agreement or the consummation of the Merger
or the other transactions contemplated hereby or thereby in breach, violation or
default of any Third  Party  Licenses  that are  material  to the conduct of the
business of the Company. Except as indicated in Schedule 5.1(o)(vi),  the rights
of the Company or any of its Subsidiaries to the Company  Intellectual  Property
will  not  be  affected  by the  execution,  delivery  or  performance  of  this
Agreement,   the  Stock  Option   Agreement  or  the  Voting  Agreement  or  the
consummation  of the  Merger or the other  transactions  contemplated  hereby or
thereby.

                  (vii)  The  Company  and its  Subsidiaries  have the  right to
license to third parties the use of the Company Owned IP.

                  (viii)  Except  as  listed  in  Schedule   5.1(o)(viii),   all
registrations and filings relating to the Company Owned IP are in good standing.
All maintenance and renewal fees necessary to preserve the rights of the Company
in  respect  of the  Company  Owned IP have been made.  Except as  indicated  in
Schedule  5.1(o)(viii),  the  registrations  and filings relating to the Company
Owned IP are proceeding and there are no material facts of which the Company has
knowledge  after due  investigation  which could  significantly  undermine those
registrations  or  filings  or  reduce  to a  significant  extent  the  scope of
protection of any patents arising from such applications.

                  (ix) The manufacturing,  marketing, distribution, sale and use
of  SU101,  SU5271,  SU5416  and  SU6668  by the  Company  or its  Subsidiaries,
licensees or  sublicensees  in the countries  where the Company has conducted or
proposes to conduct such  activities,  to the knowledge of the Company after due
investigation, does not and would not infringe the patents, patent applications,
trademarks,  trademark  applications,  service marks, service mark applications,
copyrights,  copyright  applications,  and proprietary trade names,  publication
rights,  computer programs (including source code and object code),  inventions,
know-how, trade secrets, technology, processes, confidential information and all
other   intellectual   property  rights  throughout  the  world   (collectively,
"Intellectual Property Rights") of any third party.

                                      -28-

<PAGE>

                  (x) Except for the matters  set forth in  Schedule  5.1(o)(x),
there are no  allegations,  claims or  proceedings  instituted  or pending which
challenge  the rights  possessed by the Company or its  Subsidiaries  to use the
Company  Intellectual  Property or the validity or  effectiveness of the Company
Intellectual   Property,   including  without   limitation  any   interferences,
oppositions, cancellations or other contested proceedings.

                  (xi) There are no outstanding claims or proceedings instituted
or pending by any third party  challenging  the  ownership,  priority,  scope or
validity or effectiveness of any Company Intellectual Property.

                  (xii) To the knowledge of the Company after due investigation,
there are no  Intellectual  Property Rights of any third party that have been or
would be infringed by the identification,  manufacture,  marketing, distribution
and sale and use of any products  (except  products  SU101,  SU5271,  SU5416 and
SU6668,  which  are  addressed  by  subparagraph  (ix)  above)  that  have  been
identified for development by the Company.

                  (xiii)   To  the   knowledge   of  the   Company   after   due
investigation, there are no Intellectual Property Rights of any third party that
would be infringed by the continued practice of any technologies previously used
or presently in use by the Company.

                  (xiv) To the knowledge of the Company after due investigation,
except  for  the  matters  set  forth  in  Schedule  5.1(o)(xiv),  there  is  no
unauthorized use,  infringement or misappropriation of the Company  Intellectual
Property by any third party,  including  any employee or former  employee of the
Company or any of its Subsidiaries.

                  (xv) Except for the matters set forth in Schedule  5.1(o)(xv),
the Company and its  Subsidiaries  have not  granted any  licenses,  immunities,
options or other rights to the Company Intellectual Property which could provide
a third  party  with a  defense  to  patent  infringement  proceedings,  whether
domestic or foreign.

                  (xvi)  Commercially  reasonable  measures  have been  taken to
maintain  the  confidentiality  of  the  inventions,  trade  secrets,  formulae,
know-how,  technical  information,  research data, research raw data, laboratory
notebooks,

                                      -29-


<PAGE>

procedures,  designs,  proprietary technology and information of the Company and
its Subsidiaries, and all other information the value of which to the Company or
any of its  Subsidiaries is contingent upon  maintenance of the  confidentiality
thereof.  Without limiting the generality of the foregoing, (1) each employee of
the Company and each consultant to the Company who has had access to proprietary
information  with respect to the Company has entered into an agreement  suitable
to vest ownership rights to any inventions,  creations,  developments, and works
in  the  Company  and  has  entered  into  an  agreement  for   maintaining  the
confidential information of the Company and (2) each officer and director of the
Company has entered into an agreement to maintain the  confidential  information
of the  Company,  except for those  individuals  listed in Schedule  5.1(o)(xvi)
whose  involvement in the business of the Company is described with  specificity
therein.

                  (p) Product Registration Files. The product registration files
and  dossiers  of the  Company  and its  Subsidiaries  have been  maintained  in
accordance  with  reasonable  industry  standards.  The  Company and each of its
Subsidiaries  has in its  possession  copies of all the  material  documentation
filed in connection with filings made by the Company or any of its  Subsidiaries
for  regulatory  approval or  registration  of the compounds and products of the
Company or any of its Subsidiaries,  as the case may be. To the knowledge of the
Company  after  due  investigation,  the  filings  made by the  Company  and its
Subsidiaries  for  regulatory  approval or  registration  of the products of the
Company or any of its  Subsidiaries  did not contain any untrue  statement  of a
material  fact or  omit  to  state  any  material  fact  necessary  to make  the
statements therein not misleading.

                  (q)  Year  2000  Compliance.   Schedule  5.1(q)  contains  the
Company's  Year 2000 plan,  which  indicates the actions to be taken pursuant to
such  plan that have been  completed  as of the date of this  Agreement  and the
actions to be taken pursuant to such plan that have not been completed as of the
date of this Agreement and the aggregate  expense expected to be incurred by the
Company in  connection  with the actions to be taken  pursuant to such plan that
have not been completed as of the date of this Agreement.

                  (r)  Labor  Matters.  Neither  the  Company  nor  any  of  its
Subsidiaries is a party to or otherwise bound by any

                                      -30-

<PAGE>

collective  bargaining  agreement,  contract or other agreement or understanding
with a labor  union  or labor  organization,  nor is the  Company  or any of its
Subsidiaries the subject of any material  proceeding  asserting that the Company
or any of its  Subsidiaries has committed an unfair labor practice or is seeking
to compel it to bargain with any labor union or labor  organization nor is there
pending or, to the knowledge of the Company after due investigation, threatened,
any  labor  strike,  dispute,  walkout,  work  stoppage,  slow-down  or  lockout
involving the Company or any of its Subsidiaries.

                  (s) Rights  Agreement.  The  Company  has  amended  the Rights
Agreement  to  provide  that  neither  Parent  nor  Merger  Sub nor any of their
respective affiliates shall be deemed to be an Acquiring Person (as such term is
defined in the Rights Agreement),  that neither a Distribution Date nor a Shares
Acquisition Date (as each such term is defined in the Rights Agreement) shall be
deemed to occur,  and the Rights will not separate from the Shares,  as a result
of the execution,  delivery or performance of this  Agreement,  the Stock Option
Agreement or the Voting Agreement or the consummation of the Merger or the other
transactions  contemplated  hereby or  thereby,  and that  none of the  Company,
Parent, Merger Sub, nor the Surviving  Corporation,  nor any of their respective
affiliates,  shall have any obligations under the Rights Agreement to any holder
(or former holder) of Rights as of and following the Effective Time.

                  (t)  Brokers  and  Finders.  Except as  disclosed  in Schedule
5.1(t), neither the Company nor any of its Subsidiaries,  officers, directors or
employees  has employed any broker or finder or incurred any  liability  for any
brokerage  fees,  commissions or finders' fees in connection  with the Merger or
the  other  transactions  contemplated  by  this  Agreement,  the  Stock  Option
Agreement or the Voting  Agreement,  except that the Company has employed Lehman
Brothers Inc. as its financial  advisor,  the arrangements  with which have been
disclosed to Parent prior to the date hereof.

                  (u) Supply Arrangements.  As of the date of this Agreement, to
the  Company's  knowledge  after  due  investigation,  there  are  no  facts  or
circumstances  that have materially  adversely affected or are reasonably likely
to  materially  adversely  affect the  continued  supply  (either  for  clinical
purposes or in bulk) of the active ingredients of

                                      -31-

<PAGE>


the  compounds of the Company and its  Subsidiaries  currently  used in clinical
trials.

                  (v)  Investigational   Compounds.  As  of  the  date  of  this
Agreement,  to the Company's  knowledge  after due  investigation,  there are no
facts  or  circumstances  that  have  materially   adversely  affected  or  that
management of the Company has  determined  are  reasonably  likely to materially
adversely  affect the  commercialization  of compound SU5416 or compound SU6668,
other  than  factors  that  are  generally  applicable  to the  development  and
commercialization  of  pharmaceutical  compounds  that are not  specific  to the
Company or such compounds.

                  5.2.  Representations and Warranties of Parent and Merger Sub.
Parent  and Merger  Sub each  hereby  represent  and  warrant to the  Company as
follows:

                  (a)  Capitalization  of Merger Sub.  The   authorized  capital
stock of Merger Sub consists of one thousand (1,000) shares of Common Stock, par
value $.01 per share,  all of which are validly issued and  outstanding.  All of
the issued and outstanding  capital stock of Merger Sub is, and at the Effective
Time will be,  owned by  Parent,  and there are (i) no other  shares of  capital
stock or other voting securities of Merger Sub, (ii) no securities of Merger Sub
convertible  into  or  exchangeable  for  shares  of  capital  stock  or  voting
securities  of Merger Sub and (iii) no options or other  rights to acquire  from
Merger Sub, and no obligations of Merger Sub to issue, any capital stock, voting
securities or securities  convertible  into or exchangeable for capital stock or
voting securities of Merger Sub. Merger Sub has not conducted any business prior
to the date  hereof  and has no, and prior to the  Effective  Time will have no,
assets,  liabilities  or  obligations of any nature other than those incident to
its  formation  and  pursuant  to this  Agreement  and the  Merger and the other
transactions contemplated by this Agreement.

                  (b)  Organization,  Good Standing  and  Qualification. Each of
Parent and its  Subsidiaries is a corporation  duly organized,  validly existing
and in good standing  (where such concept is  recognized)  under the laws of its
respective  jurisdiction  of  organization  and has all  requisite  corporate or
similar power and authority to own and operate its  properties and assets and to
carry on its business as presently conducted and is qualified to do business and
is

                                      -32-

<PAGE>

in good  standing as a foreign  corporation  in  each  jurisdiction  (where such
concept is  recognized)  where the  ownership or operation of its  properties or
conduct of its business requires such qualification, except where the failure to
be so qualified or in such good  standing,  when taken  together  with all other
such failures, is not reasonably likely to have a Parent Material Adverse Effect
(as defined  below).  Parent has made  available  to the Company a complete  and
correct copy of Parent's  certificate of incorporation and bylaws, as amended to
the date hereof.  Parent's  certificate of incorporation and bylaws so delivered
are in full force and effect.

                  As  used in  this  Agreement,  (i)  "Parent  Material  Adverse
Effect"  means  any  change  in or effect  on the  business  of  Parent  and its
Subsidiaries that is, or is reasonably  likely to be, materially  adverse to the
business,  assets  (including  intangible  assets),  liabilities  (contingent or
otherwise),   prospects,  condition  (financial  or  otherwise)  or  results  of
operations  of  Parent  and  its  Subsidiaries  taken  as a  whole,  and  (ii) a
"Significant  Subsidiary"  of the Company  means with  respect to the Company or
Parent, as the case may be, a direct or indirect  Subsidiary of such party which
is a significant subsidiary within the meaning of Rule 1.02(w) of Regulation S-X
promulgated pursuant to the Exchange Act.

                  (c) Capital Structure.  The authorized capital stock of Parent
consists  of  1,500,000,000  shares  of  Parent  Common  Stock,  of  which  only
508,718,107  shares  were  outstanding  as of the close of  business on June 14,
1999, and 100,000,000  shares of Preferred  Stock, par value $.01 per share (the
"Parent Preferred Stock"),  of which only 6,795 shares,  designated the Series A
convertible  Perpetual  Preferred Stock (the "Series A Preferred  Stock"),  were
outstanding as of the close of business on June 14, 1999. All of the outstanding
shares of  Parent  Common  Stock and  Series A  Preferred  Stock  have been duly
authorized and are validly issued,  fully paid and nonassessable.  Parent has no
Parent  Common  Stock  or  Parent  Preferred  Stock,  designated   Participating
Preferred Stock,  subject to issuance or subject to issuance,  except that as of
the close of business on June 14, 1999,  there were 24,818,686  shares of Parent
Common Stock reserved for issuance pursuant to Parent's Long Term Incentive Plan
(the  "Parent  Stock  Plan"),   5,087,181  shares  of  Parent  Preferred  Stock,
designated Participating Preferred Stock, subject to issuance pursuant to the

                                      -33-

<PAGE>

Stockholder Protection Rights Agreement,  dated as of March 4, 1997, between the
Parent and Harris Trust & Savings Bank, as Rights Agent, and 9,852,750 shares of
Parent Common Stock  subject to issuance  upon  conversion of shares of Series A
Preferred  Stock.  Each of the  outstanding  shares of capital  stock of each of
Parent's Significant Subsidiaries is duly authorized, validly issued, fully paid
and  nonassessable  and,  except for directors'  qualifying  shares,  owned by a
direct or indirect  wholly  owned  subsidiary  of Parent,  free and clear of any
lien, pledge, security interest, claim or other encumbrance. Except as set forth
above,  there are no shares of  capital  stock of Parent  authorized,  issued or
outstanding  and except as set forth above,  there are no preemptive  rights nor
any outstanding subscriptions, options, warrants, rights, convertible securities
or other  agreements or commitments  of any character  relating to the issued or
unissued  capital  stock or other  securities  of Parent.  Parent  does not have
outstanding  any bonds,  debentures,  notes or other obligations  the holders of
which have the right to vote (or convertible  into or exercisable for securities
having the right to vote) with the stockholders of Parent on any matter.

                  (d) Corporate Authority.

                  (i) No vote of holders of capital stock of Parent is necessary
to approve this Agreement and the Merger and the other transactions contemplated
hereby.  Each of Parent  and Merger Sub has all  requisite  corporate  power and
authority and each has taken all corporate action necessary in order to execute,
deliver and perform its  obligations  under this Agreement and to consummate the
Merger. Parent has all requisite power and authority and has taken all corporate
action necessary in order to execute,  deliver and perform its obligations under
the Stock Option  Agreement.  This Agreement is a valid and binding agreement of
Parent  and Merger  Sub,  enforceable  against  each of Parent and Merger Sub in
accordance  with its terms.  The Stock  Option  Agreement  are valid and binding
agreements  of Parent  enforceable  against  Parent  in  accordance  with  their
respective terms.

                  (ii) Prior to the Effective  Time,  Parent will have taken all
necessary  action to permit  it to issue the  number of shares of Parent  Common
Stock required to be issued pursuant to Article IV. The Parent Common Stock,

                                      -34-

<PAGE>

when  issued,  will be  validly  issued,  fully paid and  nonassessable,  and no
stockholder of Parent will have any preemptive right of subscription or purchase
in respect  thereof.  The Parent Common Stock,  when issued,  will be registered
under  the  Securities  Act and  Exchange  Act and  registered  or  exempt  from
registration under any applicable state securities or "blue sky" laws.

                  (e) Governmental  Filings;  No Violations.  (i) Other than any
filings and/or  notices  required (A) pursuant to Section 1.3, (B) under the HSR
Act,  the  Securities  Act  and the  Exchange  Act,  (C) to  comply  with  state
securities  or "blue sky" laws,  (D)  required  to be made with the NYSE and the
Stockholm  Stock  Exchange,  and (E) such  filings or  consents,  registrations,
approvals,  permits or  authorizations  as may be required under the laws of the
competition or antitrust  laws of  jurisdictions  outside the United States,  no
notices or other  filings are  required to be made by Parent or Merger Sub with,
nor  are any  consents,  registrations,  approvals,  permits  or  authorizations
required to be obtained by Parent or Merger Sub from, any  Governmental  Entity,
in connection  with the  execution and delivery of this  Agreement by Parent and
Merger Sub or the execution and delivery of the Stock Option Agreement by Parent
or the  consummation  by  Parent  and  Merger  Sub of the  Merger  and the other
transactions contemplated hereby and by the Stock Option Agreement, except those
that the failure to make or obtain are not,  individually  or in the  aggregate,
reasonably  likely  to  have  a  Parent  Material  Adverse  Effect  or  prevent,
materially  delay or  materially  impair the  ability of Parent or Merger Sub to
consummate the transactions  contemplated by this Agreement and the Stock Option
Agreement.

                  (ii) The execution, delivery and performance of this Agreement
and the Stock Option Agreement by Parent,  by Parent and Merger Sub, as the case
may be, do not and will not,  and the  consummation  by Parent and Merger Sub of
the  Merger  and the other  transactions  contemplated  hereby  and by the Stock
Option  Agreement,  will not,  constitute or result in (A) a breach or violation
of, or a default  under,  the  certificate or bylaws of Parent and Merger Sub or
the comparable governing instruments of any of its Subsidiaries, (B) a breach or
violation of, or a default under, the acceleration of or the creation of a lien,
pledge, security interest or other encumbrance on the assets of Parent or any of
its Subsidiaries (with or without notice, lapse of time

                                      -35-


<PAGE>

or  both)  pursuant  to,  any  Contracts  binding  upon  Parent  or  any  of its
Subsidiaries or any Law or governmental or non-governmental permit or license to
which  Parent or any of its  Subsidiaries  is subject,  or (C) any change in the
rights or obligations of any party under any of the  Contracts,  except,  in the
case of clause (B) or (C) above, for breach,  violation, default,  acceleration,
creation or change that,  individually  or in the  aggregate,  is not reasonably
likely to have a Parent Material Adverse Effect or prevent,  materially delay or
materially  impair  the  ability  of  Parent  or Merger  Sub to  consummate  the
transactions contemplated by this Agreement.

                  (f) Parent Reports;  Financial Statements.  Parent and, to the
extent  applicable,  each of its  then or  current  Subsidiaries,  has  made all
filings  required  to be  made  by it  with  the SEC  since  December  31,  1993
(collectively,  including any such reports filed  subsequent to the date hereof,
the "Parent  Reports") and Parent has delivered or made available to the Company
each registration  statement,  report, proxy statement or information  statement
filed with the SEC by it since  December 31, 1998 (the  "Parent  Audit Date") in
the form (including  exhibits and any amendments thereto) filed with the SEC. As
of their  respective  dates,  the Parent Reports did not, and any Parent Reports
filed with the SEC  subsequent  to the date hereof will not,  contain any untrue
statement  of a material  fact or omit to state a material  fact  required to be
stated therein or necessary to make the statements made therein, in light of the
circumstances in which they were made, not  misleading. Each of the consolidated
balance sheets  included in or incorporated by reference into the Parent Reports
(including the related notes and  schedules)  presents  fairly,  or will present
fairly, in all material respects,  the consolidated financial position of Parent
and its Subsidiaries as of its date and each of the  consolidated  statements of
income and of changes in  financial  position  included  in or  incorporated  by
reference  into the Parent  Reports  (including any related notes and schedules)
presents  fairly,  or will present fairly,  the results of operations,  retained
earnings  and changes in financial  position,  as the case may be, of Parent and
its  Subsidiaries for the periods set forth therein (except as noted therein and
subject, in the case of unaudited statements, to notes and normal year-end audit
adjustments  that will not be  material  in amount or  effect),  in each case in
accordance with GAAP consistently  applied during the periods involved,  except,
in the case of

                                      -36-

<PAGE>


unaudited  statements,  as permitted by SEC Form 10-Q and except as may be noted
therein.

                  (g) Absence of Certain  Changes.  Except as  disclosed  in the
Parent  Reports  filed  prior to the date  hereof,  since the Parent  Audit Date
Parent and its  Subsidiaries have conducted their  respective  businesses in all
material  respects  only in, and have not  engaged in any  material  transaction
other than  according to, the ordinary and usual course of such  businesses  and
there  has not been  (i) any  change  in the  financial  condition,  properties,
business  or  results  of  operations  of Parent  and its  Subsidiaries,  or any
occurrence or combination  of  occurrences  of which Parent has knowledge  that,
individually  or in the  aggregate,  has had or is  reasonably  likely to have a
Parent Material Adverse Effect;  (ii) any material damage,  destruction or other
casualty loss with respect to any material  asset or property  owned,  leased or
otherwise used by Parent or any of its  Subsidiaries,  whether or not covered by
insurance;  (iii) any  declaration,  setting aside or payment of any dividend or
other  distribution  in  respect  of the  capital  stock of  Parent,  except for
regularly quarterly dividends declared and paid on shares of Parent Common Stock
and  Series A  Preferred  Stock;  or (iv) any  change by  Parent  in  accounting
principles, practices or methods.

                  (h)  Litigation  and  Liabilities.  Except as disclosed in the
Parent Reports filed prior to the date hereof,  and except for matters which are
not,  individually  or in the  aggregate,  reasonably  likely  to have a  Parent
Material Adverse Effect or prevent or materially delay or materially  impair the
ability of Parent or Merger Sub to consummate the  transactions  contemplated by
this Agreement and the Stock Option Agreement, there are no (i) civil, criminal,
administrative or regulatory actions, suits, claims, hearings, investigations or
proceedings  pending or, to the  knowledge  of Parent  after due  investigation,
overtly threatened against Parent or any of its Subsidiaries or (ii) obligations
or liabilities,  whether or not accrued,  contingent or otherwise and whether or
not required to be disclosed,  including those relating to matters involving any
Environmental  Law, other than  liabilities  incurred in the ordinary  course of
business by Parent and its Subsidiaries since the Audit Date.

                  (i) Compliance.  Neither Parent nor any of its Subsidiaries is
in default or violation of, (i) any Law

                                      -37-

<PAGE>

applicable to Parent or any of its  Subsidiaries or by which its or any of their
respective  properties are bound, or (ii) any Contract to which Parent or any of
its Subsidiaries is a party or by which Parent or any of its Subsidiaries or its
or any of their respective properties are bound or affected, except for any such
defaults  or  violations  that,  individually  or  in  the  aggregate,  are  not
reasonably  likely  to have a Parent  Material  Adverse  Effect  or  prevent  or
materially delay the transactions contemplated by this Agreement.

                  (j) Accounting and Tax Matters. As of the date hereof,  Parent
does not have any knowledge of any fact or circumstance  relating to the Company
or its  affiliates  that would prevent  Parent from  accounting for the business
combination  to be effected by the Merger as a "pooling of interests" or prevent
the  Merger  and the other  transactions  contemplated  by this  Agreement  from
qualifying  as a  "reorganization"  within the meaning of Section  368(a) of the
Code.

                  (k)  Brokers  and  Finders.  Neither  Parent  nor  any  of its
Subsidiaries, officers, directors or employees has employed any broker or finder
or incurred any liability for any brokerage  fees,  commissions or finders' fees
in connection  with the Merger or the other  transactions  contemplated  by this
Agreement,  the Stock  Option  Agreement  or the Voting  Agreement,  except that
Parent has employed Goldman, Sachs & Co. as its financial advisor.


                                   ARTICLE VI

                                    Covenants

                  6.1.  Company Interim  Operations.  Except as set forth in the
document entitled "Schedule 6.1" furnished to the Company by Parent prior to the
execution and delivery of this Agreement, the Company covenants and agrees as to
itself  and its  Subsidiaries  that,  after  the date  hereof  and  prior to the
Effective Time (unless Parent shall  otherwise  consent in writing (such consent
not to be  unreasonably  withheld or delayed) and except as otherwise  expressly
contemplated by this Agreement and the Stock Option Agreement):


                                      -38-

<PAGE>

                  (a)  the  business  of  it  and  its  Subsidiaries   shall  be
conducted,  in all material  respects,  in the ordinary and usual course and, to
the  extent  consistent  therewith,  it and its  Subsidiaries  shall  use  their
respective  commercially  reasonable  best  efforts  to  preserve  its  business
organization  substantially  intact  and  substantially  maintain  its  existing
relations  and goodwill  with  customers,  suppliers,  distributors,  creditors,
lessors, employees and business associates;

                  (b) it  shall  not (i)  issue,  sell,  pledge,  dispose  of or
encumber any capital  stock owned by it in any of its  Subsidiaries;  (ii) amend
its  certificate or bylaws or amend,  modify or terminate the Rights  Agreement,
except as set forth in Section 5.1(s) hereof; (iii) split, combine or reclassify
its  outstanding  shares of capital  stock;  (iv) declare,  set aside or pay any
dividend  payable in cash, stock or property in respect of any capital stock, or
(v) repurchase, redeem or otherwise acquire, except in connection with the Stock
Plans, or permit any of its Subsidiaries to purchase or otherwise  acquire,  any
shares of its capital stock or any securities  convertible  into or exchangeable
or exercisable for any shares of its capital stock;

                  (c)  neither it nor any of its  Subsidiaries  shall (i) issue,
sell,  pledge,  dispose of or encumber any shares of, or securities  convertible
into  or  exchangeable  or  exercisable  for,  or  options,   warrants,   calls,
commitments or rights of any kind to acquire, any shares of its capital stock of
any class or any Voting Debt or any other property or assets (other than (A) the
issuance of Shares pursuant to options outstanding on the date of this Agreement
under the Stock Plans,  (B) the  issuance of Shares  pursuant to the exercise of
Warrants  set  forth  on  Schedule  5.1(b),  (C)  the  issuance  of  12%  Senior
Convertible Notes upon exercise of Warrant Notes outstanding on the date of this
Agreement,   (D)  the  issuance  of  warrants  for  Shares  upon  redemption  of
Convertible Notes outstanding on the date of this Agreement and (E) the issuance
of Shares upon conversion of Convertible  Notes  outstanding on the date of this
Agreement;  (ii)  other  than in the  ordinary  and usual  course  of  business,
transfer,  lease,  license,  guarantee,  sell,  mortgage, pledge,  dispose of or
encumber any other  property or assets  (including  capital  stock of any of its
Subsidiaries)  or incur or modify any material  indebtedness or other liability;
or (iii) make any commitments for, make or

                                      -39-

<PAGE>

authorize  any  capital  expenditures  other than in the  amounts set forth with
respect to particular items in the Budget or, by any means, make any acquisition
of, or investment in, assets or stock of any other Person or entity;

                  (d)  Except  as  may  be  required  by  existing   contractual
commitments,  existing corporate policy with respect to severance or termination
pay or as required by  applicable  law,  neither it nor any of its  Subsidiaries
shall (i) enter into any new  agreements  or  commitments  for any  severance or
termination pay to, or enter into employment or severance agreement with, any of
its directors, officers or employees, or (ii) terminate, establish, adopt, enter
into,  make any new  grants or awards  under,  amend or  otherwise  modify,  any
Compensation and Benefit Plans or increase or accelerate the salary, wage, bonus
or other  compensation  of any  employees,  officers  or  directors  (except for
increases in salaries,  wages and cash bonuses of nonexecutive employees made in
the ordinary  course of business  consistent with past practice) or pay or agree
to pay any pension,  retirement allowance or other employee benefit not required
by any existing Compensation and Benefit Plan;

                  (e)  neither it nor any of its  Subsidiaries  shall  settle or
compromise any material  claims or litigation or modify,  amend or terminate any
of its  material  Contracts or waive,  release or assign any material  rights or
claims;

                  (f) neither it nor any of its Subsidiaries  shall make any Tax
election  or  permit  any  insurance  policy  naming  it  as  a  beneficiary  or
loss-payable payee to be canceled or terminated except in the ordinary and usual
course of business;

                  (g) except as may be  required  as a result of a change in law
or in  generally  accepted  accounting  principles,  neither  it nor  any of its
Subsidiaries shall change any of the accounting  practices or principles used by
it;

                  (h) neither it nor any of its Subsidiaries  shall adopt a plan
of  complete  or  partial  liquidation,   dissolution,   merger,  consolidation,
restructuring,  recapitalization,  or other reorganization of the Company or any
of its  subsidiaries  not  constituting an inactive  Subsidiary  (other than the
Merger);


                                      -40-

<PAGE>

                  (i)  neither it nor any of its  Subsidiaries  shall  knowingly
take any action, or knowingly fail to take any action, that is reasonably likely
to  jeopardize  the  treatment  of the Merger as a "pooling  of  interests"  for
accounting  purposes  or as a  "reorganization"  within  the  meaning of Section
368(a) of the Code or that would cause any of its representations and warranties
herein to be or become untrue in any material respect;

                  (j) it  shall  not  suffer  or  permit  expenditures  made  or
incurred by the Company and its Subsidiaries for any period to materially exceed
the  Projected  Expenses  for  such  period  except  for  expenses  incurred  in
connection with the transactions contemplated by this Agreement; and

                  (k) neither it nor any of its  Subsidiaries  will offer to, or
enter into an agreement to, do any of the foregoing.

                  6.2.  Conduct of  Business  of Parent.  Parent  covenants  and
agrees as to itself and its  Subsidiaries  that, after the date hereof and prior
to the  Effective  Time (unless the Company shall  otherwise  consent in writing
(such  consent  not to be  unreasonably  withheld  or  delayed)  and  except  as
otherwise  expressly  contemplated  by  this  Agreement  and  the  Stock  Option
Agreement):

                  (a) it shall not amend the terms of the Parent Common Stock;

                  (b) it shall not  acquire or agree to  acquire,  by merging or
consolidating  with, or by purchasing a substantial portion of the assets of, or
by any  other  manner,  any  business  of any  corporation,  partnership,  joint
venture,  association or other business  organization  or division  thereof,  or
otherwise acquire or agree to acquire, or dispose of or agree to dispose of, any
assets of any person, which, in each case, could reasonably be expected to delay
materially   the   consummation   of,  or  increase   materially   the  risk  of
non-consummation of, the transaction contemplated by this Agreement;

                  (c) except as may be  required  as a result of a change in law
or in generally  accepted  accounting  principles,  it shall not change,  in any
material respect, any of the accounting practices or principles used by it;


                                      -41-

<PAGE>

                  (d) it shall not  knowingly  take any action that would result
in a failure of Parent Common Stock to be listed on the NYSE;

                  (e)  neither it nor any of its  Subsidiaries  shall  knowingly
take any action, or knowingly fail to take any action, that is reasonably likely
to  jeopardize  the  treatment  of the Merger as a "pooling  of  interests"  for
accounting  purposes  or as a  "reorganization"  within  the  meaning of Section
368(a) of the Code or that would cause any of its representations and warranties
herein to be or become untrue in any material respect; and

                  (f) neither it nor any of its  Subsidiaries  will offer to, or
enter into any agreement to, do any of the foregoing.

                  6.3. Acquisition Proposals. The Company shall, and shall cause
its nonstockholder  affiliates and the officers,  directors and employees of the
Company and its subsidiaries  to, and shall instruct its stockholder  affiliates
and  the  representatives  and  agents  of  the  Company  and  its  subsidiaries
(including,  without limitation,  any investment banker,  attorney or accountant
retained by the Company or any of its  subsidiaries)  to,  immediately cease and
terminate any existing activities, discussions or negotiations, if any, with any
parties conducted  heretofore with respect to any acquisition or exchange of all
or any  material  portion  of the  assets  of,  or more  than 15% of the  equity
interest in, the Company or any of its Subsidiaries (by direct purchase from the
Company,  tender or exchange  offer or otherwise)  or any business  combination,
merger or similar transaction (including an exchange of stock or assets) with or
involving  the  Company  or  any  Subsidiary  or  division  of the  Company  (an
"Acquisition  Transaction"),  other than the Merger. Except as set forth in this
Section  6.2,  the  Company  shall  not,  and  shall  cause  its  nonstockholder
affiliates  and the  officers,  directors  and  employees of the Company and its
subsidiaries  not to, and shall  instruct  its  stockholder  affiliates  and the
representatives  and  agents of the  Company  and its  subsidiaries  (including,
without  limitation,  any investment banker,  attorney or accountant retained by
the  Company  or  any of its  subsidiaries)  not  to,  directly  or  indirectly,
knowingly  encourage,   solicit,  participate  in  or  initiate  discussions  or
negotiations  with, or provide any information or data (other than the Company's
standard public

                                      -42-

<PAGE>

information package) to, any corporation, partnership, person or other entity or
group  (other than Parent and Merger Sub,  any  affiliate or associate of Parent
and Merger Sub or any  designees  of Parent and Merger Sub) with  respect to any
inquiries or the making of any offer or proposal (including, without limitation,
any  offer  or  proposal  to the  stockholders  of the  Company)  concerning  an
Acquisition  Transaction  (an  "Acquisition  Proposal")  or otherwise  knowingly
facilitate any effort or attempt to make or implement an  Acquisition  Proposal;
provided,  however,  that prior to the receipt of the Company Requisite Vote the
Company may furnish  information  and access,  but only in response to a request
for  information  or access,  to any person or entity making a bona fide written
Acquisition  Proposal to the board of  directors  of the Company  after the date
hereof which was not knowingly encouraged, solicited or initiated by the Company
or any of its affiliates or any director,  employee,  representative or agent of
the  Company or any of its  subsidiaries  (including,  without  limitation,  any
investment banker,  attorney or accountant retained by the Company or any of its
subsidiaries) on or after the date hereof and may participate in discussions and
negotiate with such person or entity  concerning any such  Acquisition  Proposal
and authorize the Company,  subject to compliance with Section 8.3(a),  to enter
into a binding  written  agreement  concerning  a Superior  Proposal (as defined
below),  if and only if, in any such  case,  (i) the board of  directors  of the
Company determines in good faith, (A) taking into account the written,  reasoned
advice of outside  counsel to the Company to the effect that  failing to provide
such information or access or to participate in such discussions or negotiations
or so to  authorize,  as the case may be, is  reasonably  likely to constitute a
breach of such board's  fiduciary  duties under  applicable law, that failing to
provide such  information  or access or to  participate  in such  discussions or
negotiations or to so authorize,  as the case may be, would  constitute a breach
of such  board's  fiduciary  duties  under  applicable  law, and (B) taking into
account the written advice of financial  advisors to the Company to such effect,
that  such  Acquisition  Proposal,  if  accepted,  is  reasonably  likely  to be
consummated,  taking into account all legal, financial and regulatory aspects of
the  proposal  and the  person or entity  making  the  proposal  and  would,  if
consummated,   result  in  a  transaction   more   favorable  to  the  Company's
stockholders from a financial point of view than the transaction contemplated by
this Agreement (any such more favorable Acquisition Proposal as to which both of
the

                                      -43-

<PAGE>

determinations  referred  to in  subclauses  (A) and (B) of this clause (i) have
been made being  referred to in this  Agreement as a "Superior  Proposal"),  and
(ii) the board of  directors of the Company  receives  from the person or entity
making such bona fide written Acquisition  Proposal an executed  confidentiality
agreement  the  terms  of  which  are  (without  regard  to the  terms  of  such
Acquisition  Proposal)  (A) no less  favorable to the  Company,  and (B) no less
restrictive  to the person or entity  making such bona fide written  Acquisition
Proposal than those contained in the Confidentiality  Agreement, dated as of May
21, 1999,  referring to Parent as the "Recipient" (the "Company  Confidentiality
Agreement"),  between the Company and Parent.  Nothing in this  Agreement  shall
prohibit the Board of Directors of the Company from,  to the extent  applicable,
complying with Rule 14e-2  promulgated  under the Exchange Act with regard to an
Acquisition Proposal. The Company will notify Parent within 36 hours if any such
inquiries or proposals are received by, any such  information is requested from,
or any such  negotiations or discussions are sought to be initiated or continued
with the Company and shall in such notice  indicate  the identity of the offeror
and the terms and  conditions  of any such  proposal and  thereafter  shall keep
Parent  informed,  on a current basis, of the status and terms of such proposals
and the status of such  negotiations or discussions,  providing copies to Parent
of any Acquisition  Proposals made in writing.  The Company shall provide Parent
with five days' advance notice of its intention to enter into any agreement with
or to provide any information to any person or entity making any such inquiry or
proposal.  The Company  agrees not to release any third party from, or waive any
provisions of, any confidentiality or standstill  agreement to which the Company
is a party.  The Company will inform the individuals or entities  referred to in
the first  sentence of this Section 6.3 of the  obligations  undertaken  in this
Section 6.3. The Company also will promptly  request each person or entity which
has  executed,  within  36  months  prior  to the  date  of  this  Agreement,  a
confidentiality  agreement in connection with its consideration of acquiring the
Company to return or destroy all confidential  information  heretofore furnished
to such person or entity by or on behalf of the Company.

                  6.4.  Information  Supplied.  Each of the  Company  and Parent
agrees, as to itself and its Subsidiaries, that none of the information supplied
or to be supplied by it or its  Subsidiaries  for inclusion or  incorporation by
reference

                                      -44-

<PAGE>

in (i) the Registration Statement on Form S-4 to be filed with the SEC by Parent
in  connection  with the issuance of shares of Parent Common Stock in the Merger
(including the proxy statement and prospectus (the "Prospectus/Proxy Statement")
constituting a part thereof) (the  "Registration  Statement")  will, at the time
the Registration  Statement  becomes effective under the Securities Act, contain
any untrue  statement  of a  material  fact or omit to state any  material  fact
required to be stated  therein or necessary to make the statements  therein,  in
light of the circumstances under which they were made, not misleading,  and (ii)
the Prospectus/Proxy  Statement and any amendment or supplement thereto will, at
the  date of  mailing  to  stockholders  and at the  times  of the  meetings  of
stockholders  of the Company to be held in connection  with the Merger,  contain
any untrue  statement  of a  material  fact or omit to state any  material  fact
required  to be stated  therein  or  necessary  in order to make the  statements
therein,  in  light  of the  circumstances  under  which  they  were  made,  not
misleading.

                  6.5.   Stockholders   Meeting.   The  Company  will  take,  in
accordance with applicable law and its certificate of incorporation  and bylaws,
all  action   necessary   to  convene  a  meeting  of  holders  of  Shares  (the
"Stockholders   Meeting")  as  promptly  as  reasonably  practicable  after  the
Registration  Statement  is declared  effective  to  consider  and vote upon the
adoption of this Agreement. Subject to fiduciary obligations under the DGCL, the
board of directors of the Company shall  recommend such adoption and the Company
shall use its reasonable best efforts to solicit such adoption.

                  6.6. Filings; Other Actions;  Notification. (a) Parent and the
Company  shall  promptly  prepare  and file  with  the SEC the  Prospectus/Proxy
Statement,  and  Parent  shall  prepare  and file with the SEC the  Registration
Statement,  as promptly as  practicable.  Parent and the Company shall use their
commercially  reasonable best efforts to cause the Registration  Statement to be
declared  effective  under the Securities  Act as promptly as practicable  after
such filing, and promptly thereafter mail the Prospectus/Proxy  Statement to the
stockholders of the Company.  Parent shall also use its commercially  reasonable
best efforts to obtain prior to the effective date of the Registration Statement
all necessary state securities law or "blue sky" permits and approvals  required
in connection with the Merger and the consummation of the other transactions

                                      -45-

<PAGE>

contemplated  by this Agreement and the Stock Option  Agreement and will pay all
expenses incident thereto.

                  (b) The Company  shall use its  commercially  reasonable  best
efforts to cause to be  delivered  to Parent and its  directors  a letter of its
independent  auditors,  dated (i) the date on which the  Registration  Statement
shall become  effective  and (ii) the third  business day prior to the Effective
Time, and addressed to Parent and its directors, in form and substance customary
for "comfort" letters delivered by independent  public accountants in connection
with registration statements similar to the Registration Statement.

                  (c) The Company and Parent shall cooperate with each other and
use (and shall  cause their  respective  Subsidiaries  to use) their  respective
commercially   reasonable best efforts to take or cause to be taken all actions,
and do or cause to be done all things, necessary, proper or advisable under this
Agreement,  the Stock Option Agreement, the Voting Agreement and applicable Laws
to  consummate  and  make  effective  the  Merger  and  the  other  transactions
contemplated  by this  Agreement,  the Stock  Option  Agreement  and the  Voting
Agreement as soon as practicable,  including preparing and filing as promptly as
practicable all  documentation  to effect all necessary  applications,  notices,
petitions,  filings and other documents and to obtain as promptly as practicable
all permits, consents, approvals and authorizations necessary or advisable to be
obtained  from any  third  party  and/or  any  Governmental  Entity  in order to
consummate  the  Merger or any of the other  transactions  contemplated  by this
Agreement,  the Stock Option Agreement and the Voting Agreement.  In particular,
the  Company  and Parent each agree to use  commercially  reasonable  efforts to
take, or cause to be taken, all appropriate action, and do, or cause to be done,
such things as may be necessary  under federal or state  securities  laws or the
HSR Act or  Foreign  Merger  Laws  (as  hereinafter  defined)  applicable  to or
necessary  for,  and  will  file as  soon  as  reasonably  practicable  and,  if
appropriate,  use commercially  reasonable efforts to have declared effective or
approved, all documents and notifications with the SEC and other governmental or
regulatory bodies (including, without limitation, the FDA and equivalent foreign
regulatory  bodies,  and other foreign regulatory bodies that administer Foreign
Merger Laws,  and any foreign labor  councils or bodies as may be required) that
they deem necessary or

                                      -46-

<PAGE>

appropriate for, the consummation of the Merger or any of the other transactions
contemplated hereby, and each party shall give the other information  reasonably
requested  by  such  other  party  pertaining  to it and  its  subsidiaries  and
affiliates to enable such other party to take such actions. Although the parties
do not anticipate any legislative,  administrative or judicial  objection to the
consummation  of the  Merger  or any of the  transactions  contemplated  by this
Agreement, each of the Company, Parent and Merger Sub agrees to use commercially
reasonable  efforts to contest  and resist any  action,  including  legislative,
administrative  or judicial  action,  and to have vacated,  lifted,  reversed or
overturned any decree,  judgment,  injunction or other order (whether temporary,
preliminary  or  permanent)  that is in effect and that  restricts,  prevents or
prohibits  the  consummation  of the  Merger  or any of the  other  transactions
contemplated  by this  Agreement,  including,  without  limitation,  by pursuing
available  avenues of administrative  and judicial appeal.  Each of the Company,
Parent and Merger Sub also agrees to use commercially reasonable efforts to take
any and all actions  necessary to avoid or eliminate  each and every  impediment
under any  antitrust  law that may be  asserted  by any  governmental  antitrust
authority  or any other  party so as to enable the  parties to close by the date
specified in Section  8.2(i) the  transactions  contemplated  hereby;  provided,
however,  that  nothing in this  Section 6.6 shall  require,  or be construed to
require,  Parent to proffer to, or agree to, sell or hold  separate and agree to
sell, before or after the Effective Time, any assets, businesses, or interest in
any assets or  businesses  of  Parent,  the  Company or any of their  respective
affiliates  (or to consent to any sale,  or agreement to sell, by the Company of
any of its  assets  or  businesses)  or to  agree  to any  material  changes  or
restriction in the  operations of any such assets or  businesses;  and provided,
further,  that  nothing in this  Section 6.6 shall  require,  or be construed to
require,  a proffer or  agreement  that  would,  in the good faith  judgment  of
Parent,  be  reasonably  likely  to have a  significant  adverse  effect  on the
benefits to Parent of the transactions  contemplated by this Agreement.  Subject
to  applicable  Laws  relating to the  exchange of  information,  Parent and the
Company shall have the right to review in advance, and to the extent practicable
each will  consult the other on, all the  information  relating to Parent or the
Company,  as the case may be,  and any of their  respective  Subsidiaries,  that
appear in any filing made with,  or written  materials  submitted  to, any third
party and/or any Governmental Entity

                                      -47-

<PAGE>

in connection  with the Merger and the other  transactions  contemplated by this
Agreement,  the Stock Option Agreement and the Voting  Agreement.  In exercising
the foregoing right,  each of the Company and Parent shall act reasonably and as
promptly as practicable.

                  (d) The Company and Parent  each  shall,  upon  request by the
other,   furnish  the  other  with  all  information   concerning   itself,  its
Subsidiaries, directors, officers and stockholders and such other matters as may
be reasonably  necessary or advisable in connection  with  the  Prospectus/Proxy
Statement, the Registration Statement or any other statement,  filing, notice or
application  made  by or on  behalf  of  Parent,  the  Company  or any of  their
respective  Subsidiaries  to any third party and/or any  Governmental  Entity in
connection with the Merger and the transactions  contemplated by this Agreement,
the Stock Option Agreement and the Voting Agreement.

                  (e) The Company and Parent each shall keep the other  apprised
of  the  status  of  matters   relating  to   completion  of   the  transactions
contemplated  hereby,  including  promptly  furnishing  the other with copies of
notice or other  communications  received by Parent or the Company,  as the case
may be, or any of its Subsidiaries, from any third party and/or any Governmental
Entity with  respect to the Merger and the other  transactions  contemplated  by
this Agreement, the Stock Option Agreement and the Voting Agreement. The Company
and Parent  each shall give  prompt  notice to the other of any change  that has
resulted  in or is  reasonably  likely to result in a Company  Material  Adverse
Effect or Parent Material Adverse Effect, respectively.

                  (f)  Parent  shall  notify  the  Company  promptly  (i) of the
receipt  of the  comments  of the  SEC,  (ii)  of any  request  by the  SEC  for
amendments or supplements to the Registration Statement,  (iii) of the time when
the  Registration  Statement has become effective or any supplement or amendment
has been filed,  or the issuance of any stop order and (iv) of the suspension of
the  qualification  of the Parent Common Stock  issuable in connection  with the
Merger for  offering or sale in any  jurisdiction,  and shall supply the Company
with copies of all correspondence  with the SEC with respect to the Registration
Statement.


                                      -48-

<PAGE>

                  (g) If at any time prior to the Effective  Time,  any event or
circumstance  relating to the Company,  any Subsidiary,  or the Company's or any
Subsidiary's officers or directors should occur and be discovered by the Company
that is required to be described in an amendment or supplement to the definitive
Proxy  Statement/Prospectus  or the  Registration  Statement,  the Company shall
promptly inform Parent. If at any time prior to the Effective Time, any event or
circumstance  relating to Parent or any of its  subsidiaries or their respective
officers or directors  should occur and be discovered by Parent that is required
to  be  described  in  an  amendment  or  supplement  to  the  definitive  Proxy
Statement/Prospectus or the Registration Statement, Parent shall promptly inform
the Company.  Whenever any event occurs that should be described in an amendment
of,  or  supplement  to,  the  definitive  Proxy   Statement/Prospectus  or  the
Registration  Statement,  the Company or Parent, as the case may be, shall, upon
learning of such event, promptly notify the other and consult and cooperate with
the other in connection with the preparation of a mutually acceptable  amendment
or supplement. The parties shall promptly file such amendment or supplement with
the SEC and mail such amendment or supplement as soon as practicable after it is
cleared by the SEC. No amendment or supplement to the Proxy Statement/Prospectus
or the Registration  Statement will be made by Parent or the Company without the
approval of the other party (such  approval not to be  unreasonably  withheld or
delayed).

                  (h) The  Company  will use its  commercially  reasonable  best
efforts to obtain,  as soon as  practicable  prior to the  Effective  Time,  the
consents and waivers required under the Contracts listed in Schedule  5.1(d)(ii)
in connection  with the  consummation of the  transactions  contemplated by this
Agreement and the Stock Option Agreement.

                  (i) The Company will periodically  provide Parent with current
draft  versions of any filings to be made by the Company  subsequent to the date
hereof  pursuant  to the  Securities  Act or the  Exchange  Act,  including  any
documents incorporated therein by reference,  promptly after preparation of such
draft.

                  6.7. Taxation and Accounting. (a) At or prior to the filing of
the  Registration  Statement  and at or prior to the  Closing,  the  Company and
Parent shall execute and

                                      -49-

<PAGE>

deliver to Cooley  Godward  LLP and to  Sullivan & Cromwell  tax  representation
letters  reasonably   satisfactory  to  such  counsel  setting  forth  customary
representations  which may be  relied  upon by such  counsel  in  rendering  any
opinions   contemplated  by  this  Agreement.   Parent  shall  use  commercially
reasonable  efforts to cause  Sullivan  & Cromwell  to deliver to Parent a legal
opinion,  satisfying the  requirements of Item 601 of Regulation S-K promulgated
under  the  Securities  Act and  dated  as of a date  that is no more  than  two
business days prior to the date of filing of the Registration  Statement, to the
effect that the Merger will  constitute a  reorganization  within the meaning of
Section  368(a) of the  Code,  based in part on the tax  representation  letters
described in this Section 6.7(a). The Company shall use commercially  reasonable
efforts to cause Cooley  Godward LLP to deliver to the Company a legal  opinion,
satisfying the requirements of Item 601 of Regulation S-K promulgated  under the
Securities  Act and dated as of a date that is no more  than two  business  days
prior to the date of filing of the  Registration  Statement,  to the effect that
the Merger will constitute a reorganization within the meaning of Section 368(a)
of the Code, based in part on the tax  representation  letters described in this
Section 6.7(a).

                  (b) Parent  shall  cooperate  with the Company and the Company
shall use  reasonable  best  efforts to cause to be  delivered to Parent and the
Company,  a letter from Ernst & Young LLP  addressed to the  Company,  as of the
Closing Date,  stating that based upon discussions with officials of the Company
responsible for financial and accounting matters,  and information  furnished to
Ernst & Young LLP to the date of its letter,  Ernst & Young LLP concurs with the
Company's  management's  conclusion  that,  as of the  date  of its  letter,  no
conditions exist related to the Company that would preclude Parent's  accounting
for the Merger as a pooling of interests.

                  (c) The Company shall  cooperate  with Parent and Parent shall
use  reasonable  best efforts to cause to be delivered to Parent,  a letter from
PricewaterhouseCoopers  LLP  addressed to Parent,  dated as of the Closing Date,
confirming as of the Closing Date that, based upon discussions with officials of
Parent  responsible for financial and accounting matters and the letter provided
by Ernst & Young LLP to the  Company,  PricewaterhouseCoopers  LLP concurs  with
Parent management's conclusions that the Merger

                                      -50-

<PAGE>

will  qualify  as a pooling of  interests  transaction  under  Opinion 16 of the
Accounting Principles Board and applicable SEC rules and regulations.

                  6.8.  Access.  Upon  reasonable  notice,  and  except  as  may
otherwise be required by  applicable  law,  each of the Company and Parent shall
(and shall cause its  Subsidiaries to) afford the other's  officers,  employees,
counsel,  accountants and other authorized  representatives  ("Representatives")
access,  during  normal  business  hours  throughout  the  period  prior  to the
Effective  Time, to its properties,  books,  contracts,  records,  personnel and
advisors and, during such period,  each shall (and shall cause its  Subsidiaries
to) furnish promptly to the other all documents, data and information concerning
its  business,  properties  (tangible  and  intangible)  and  personnel  as  may
reasonably  be  requested.  The Company and Parent shall  provide  access to the
information  described above  regardless of whether or not such documents,  data
and information are or may be covered by the attorney-client privilege, lawyer's
work product privilege or other privileges  against  disclosure,  as the parties
have  concluded  that  such  disclosure  shall  not  constitute  a waiver of the
attorney-client  or any  other  privilege  due to  the  substantially  identical
interest  of the  Company  and  Parent  with  respect  to such  information.  No
investigation  pursuant to this Section  shall affect or be deemed to modify any
representation  or  warranty  made  by  the  Company,  Parent or Merger  Sub. No
provision of this  Agreement  shall  require the Company or Parent to permit any
inspection,  or to disclose any information,  that in the reasonable judgment of
the Company or the Parent, as the case may be, would result in the disclosure of
any trade  secrets of third parties or violate any of its  obligations  to third
parties with respect to  confidentiality  if the Company or Parent,  as the case
may be, shall have used  reasonable  efforts to obtain the consent of such third
party to such  inspection  or  disclosure.  All  requests for  information  made
pursuant  to this  Section  shall be  directed  to an  executive  officer of the
Company or Parent,  as the case may be, or such  Person as may be designated  by
either of its  officers.  All such  information  shall be subject to the Company
Confidentiality Agreement and the Confidentiality Agreement, dated as of May 21,
1999,  referring to the Company as the  Recipient  (the "Parent  Confidentiality
Agreement"), between the Company and Parent, as the case may be.


                                      -51-

<PAGE>

                  6.9. Affiliates. (i) Prior to the Effective Time, Parent shall
deliver to the Company a list of names and  addresses of those  Persons who are,
in the opinion of Parent, as of the time of the Stockholders Meeting referred to
in Section 6.5, "affiliates" of the Company within the meaning of Rule 145 under
the Securities Act and for the purposes of applicable  interpretations regarding
the pooling of interests  method of  accounting.  The Company  shall  provide to
Parent such  information  and documents as Parent shall  reasonably  request for
purposes of such list. There shall be added to such list the names and addresses
of any other Person the Company later  identifies as an affiliate of the Company
or Parent  reasonably  identifies  (by written  notice to the Company within ten
business  days after the  Company's  receipt of such list) as being a Person who
may be deemed to be such an affiliate of the Company; provided, however, that no
such Person identified by Parent shall be added to the list of affiliates of the
Company if Parent shall  receive from the Company,  on or before the date of the
Stockholders Meeting, an opinion of counsel reasonably satisfactory to Parent to
the  effect  that  such  Person  is not an  affiliate.  The  Company  shall  use
reasonable  efforts to deliver or cause to be delivered to Parent,  prior to the
date of the  Stockholders  Meeting,  (i)  from  each of such  affiliates  of the
Company  identified in the foregoing  list (as the same may be  supplemented  as
aforesaid),  other than  AstraZeneca  plc, a letter dated as of the Closing Date
substantially  in the form  attached  as Exhibit  A-1 (the  "Company  Affiliates
Letter"),  and (ii) from  AstraZeneca  plc a letter dated as of the Closing Date
substantially in the form attached as Exhibit AZ-1 (the  "AstraZeneca  Affiliate
Letter").

                  (ii) Parent shall use  reasonable  efforts to obtain from each
of those  Persons  who are,  in the  opinion of Parent,  "affiliates"  of Parent
within the meaning of Rule 145 under the  Securities Act and for the purposes of
applicable   interpretations  regarding  the  pooling  of  interests  method  of
accounting  a letter  dated as of the  Closing  Date  substantially  in the form
attached as Exhibit A-2 (the "Pooling Affiliates Letter").

                  (iii) If the Merger  would  otherwise  qualify  for pooling of
interests  accounting  treatment,  shares of Parent  Common Stock issued to such
affiliates of the Company in exchange for Shares shall not be transferable until
such time as financial results covering at least 30 days of

                                      -52-

<PAGE>

combined  operations  of Parent and the Company have been  published  within the
meaning of  Section  201.01 of the SEC's  Codification  of  Financial  Reporting
Policies,  regardless  of whether each such  affiliate  has provided the written
agreement referred to in this Section, except to the extent permitted by, and in
accordance with, Accounting Series Release 135 and Staff Accounting Bulletins 65
and 76. Any Shares held by such affiliates shall not be transferable, regardless
of whether each such affiliate has provided the written agreement referred to in
this Section,  if such  transfer,  either alone or in the  aggregate  with other
transfers by  affiliates,  would  preclude  Parent's  ability to account for the
business combination to be effected by the Merger as a pooling of interests. The
Company shall not register the transfer of any Certificate, unless such transfer
is made in compliance with the foregoing.

                  6.10.  Listing;  De-registration.  Parent  shall  use its best
efforts to cause the shares of Parent Common Stock to be issued in the Merger to
be approved  for listing on the NYSE  subject to  official  notice of  issuance,
prior to the Closing  Date.  The Company shall use its best efforts to cause the
Shares to be  de-registered  from the Nasdaq National  Market and  de-registered
under the Exchange Act as soon as practicable following the Effective Time.

                  6.11. Publicity. Parent shall control and coordinate the press
relations and publicity activities of the parties in connection with the Merger.
The Company shall consult with Parent with respect to issuing any press releases
or  otherwise  making  public  announcements  with respect to the Merger and the
other transactions  contemplated by this Agreement, the Voting Agreement and the
Stock Option  Agreement and will not issue any press  releases or otherwise make
any public  announcements  with respect thereto  without  Parent's prior consent
(which consent shall not be unreasonably withheld), except as may be required by
law or pursuant to the Company's  listing  agreement with or rules of the Nasdaq
National Market.

                  6.12. Benefits.

                  (a) Stock Options.

                  (i) At the Effective  Time,  each  outstanding  Company Option
under the Stock Plans, whether vested or unvested, shall be deemed to constitute
an option to acquire

                                      -53-

<PAGE>

(a "New Parent  Option"),  on the same terms and  conditions as were  applicable
under such  Company  Option,  the same number of shares of Parent  Common  Stock
(rounded to the nearest whole number) as the holder of such Company Option would
have been entitled to receive  pursuant to the Merger had such holder  exercised
such option in full  immediately  prior to the  Effective  Time,  at an exercise
price per share  (rounded to the nearest  whole cent) equal to (y) the aggregate
exercise  price for the Shares  otherwise  purchasable  pursuant to such Company
Option  divided by (z) the number of full shares of Parent  Common  Stock deemed
purchasable  pursuant to such Company  Option in accordance  with the foregoing;
provided,  however,  that in the case of any Company Option to which Section 422
of the Code applies, the option price, the number of shares purchasable pursuant
to such option and the terms and  conditions of exercise of such option shall be
determined in accordance with the foregoing,  subject to such adjustments as are
necessary in order to satisfy the requirements of Section 424(a) of the Code. At
or prior to the Effective Time, the Company shall take all necessary  actions to
permit the assumption of the  unexercised  Company Options by Parent pursuant to
this Section.

                  (ii) Effective at the Effective Time,  Parent shall assume, as
a New Parent Option,  each  outstanding  Company Option in accordance  with this
Section  and with the terms of the Stock Plan under  which it was issued and the
stock  option  agreement by which it is  evidenced.  Not later than ten calendar
days after the Closing Date,  Parent shall file a registration  statement  under
the  Securities  Act of 1933 on Form S-8, or other  appropriate  form,  covering
shares of Parent Common Stock subject to such New Parent Options.

                  (b) Employee  Benefits.  Parent  agrees that during the period
commencing at the Effective  Time and ending on the first  anniversary  thereof,
the Employees will continue to be provided with benefits under employee  benefit
plans  (other  than stock  options or other  plans  involving  the  issuance  of
securities of the Company or Parent)  which in the  aggregate are  substantially
comparable  to  those  currently  provided  by the  Company  to such  Employees;
provided,  however,  that Employees covered by collective  bargaining agreements
need not be provided with such benefits. Parent will cause each employee benefit
plan of Parent in which  Employees  are  eligible  to  participate  to take into
account for purposes of eligibility and vesting

                                      -54-

<PAGE>
thereunder  the service of such  Employees  with the Company as if such  service
were with  Parent,  to the same extent that such  service was  credited  under a
comparable  plan of the  Company.  Parent  will,  and will  cause the  Surviving
Corporation  to, honor in accordance  with their terms (i) all employee  benefit
obligations to current and former Employees accrued as of the Effective Time and
(ii) to the extent set forth on Schedule 5.1(h)(i), all employee severance plans
in  existence  on the date hereof and all  employment  or  severance  agreements
entered into prior to the date hereof.

                  6.13.  Expenses.  The  Surviving  Corporation  shall  pay  all
charges and expenses,  including those of the Exchange Agent, in connection with
the  transactions  contemplated  in Article IV, and Parent shall  reimburse  the
Surviving  Corporation  for such  charges  and  expenses.  Except  as  otherwise
provided in Section 8.5(b), whether or not the Merger is consummated,  all costs
and  expenses  incurred in  connection  with this  Agreement,  the Stock  Option
Agreement,  the  Voting  Agreement  and the  Merger  and the other  transactions
contemplated  by this  Agreement,  the Stock  Option  Agreement  and the  Voting
Agreement shall be paid by the party incurring such expense.

                  6.14. Indemnification; Directors' and Officers' Insurance. (a)
From and after the Effective Time, Parent agrees that it will indemnify,  defend
and  hold  harmless  each  individual  entitled  to  indemnification  as of  the
Effective Time under the Company's certificate of incorporation and bylaws as in
effect on the date of this Agreement (the  "Indemnified  Parties"),  against any
costs or expenses  (including  reasonable  attorneys' fees),  judgments,  fines,
losses,  claims,  damages or  liabilities  (collectively,  "Costs")  incurred in
connection with any claim,  action, suit,  proceeding or investigation,  whether
civil,  criminal,  administrative  or  investigative,  arising  out  of  matters
existing or occurring at or prior to the Effective Time (including  transactions
contemplated  by this  Agreement),  whether  asserted or claimed prior to, at or
after the Effective Time, to the fullest extent that the Company would have been
permitted under the DGCL and its certificate of incorporation,  bylaws and other
agreements  (including  the  Indemnification  Agreements  referred  to below) in
effect on the date  hereof to  indemnify  such  Person  (and  Parent  shall also
advance  expenses as incurred to the fullest extent  permitted under  applicable
law,  provided the Person to whom expenses are advanced  provides an undertaking
to repay such

                                      -55-

<PAGE>

advances if it is  ultimately  determined  that such  Person is not  entitled to
indemnification).

                  (b) From and after the Effective  Time,  Parent will cause the
Surviving  Corporation  to fulfill and honor in all respects the  obligations of
the  Company  pursuant  to each  indemnification  agreement  listed in  Schedule
6.14(b).

                  (c) Any  Indemnified  Party  wishing to claim  indemnification
under  paragraph  (a) of this  Section  6.14,  upon  learning of any such claim,
action, suit, proceeding or investigation, shall promptly notify Parent thereof.
In the  event of any such  claim,  action,  suit,  proceeding  or  investigation
(whether  arising  before  or after  the  Effective  Time),  (i)  Parent  or the
Surviving  Corporation  shall have the right to assume the  defense  thereof and
Parent shall not be liable to such Indemnified Parties for any legal expenses of
other counsel or any other expenses  subsequently  incurred by such  Indemnified
Parties in  connection  with the defense  thereof  unless there is a conflict of
interest between the Indemnified Parties and Parent, in which event Parent shall
be liable to the Indemnified  Parties for the fees and expenses of not more than
one firm of counsel,  (ii) the Indemnified Parties will cooperate in the defense
of any such  matter  and (iii)  Parent  shall not be liable  for any  settlement
effected  without its prior written  consent and no  Indemnified  Party shall be
liable for any settlement effected without its prior written consent unless such
settlement includes a complete release of claims against such Indemnified Party;
and provided,  further,  that Parent shall not have any obligation  hereunder to
any  Indemnified  Party  if and  when a court of  competent  jurisdiction  shall
ultimately  determine,  and such determination shall have become final, that the
indemnification of such Indemnified Party in the manner  contemplated  hereby is
prohibited by applicable law.

                  (d)  Notwithstanding any contrary provision of this Agreement,
prior to the  Effective  Time,  the  Company  may  purchase  insurance  coverage
extending  for a period of six  years the  Company's  directors'  and  officers'
liability  insurance  coverage in effect as of the date hereof (covering past or
future  claims with  respect to periods  prior to and  including  the  Effective
Time);  provided that the aggregate premium payable for such insurance shall not
exceed 175% of the last annual  premium paid for such coverage prior to the date
hereof.

                                      -56-

<PAGE>

                  (e) If the Surviving  Corporation  or any of its successors or
assigns (i) shall consolidate with or merge into any other corporation or entity
and shall  not be the  continuing  or  surviving  corporation  or entity of such
consolidation or merger or (ii) shall transfer all or  substantially  all of its
properties and assets to any individual,  corporation or other entity,  then and
in each such case,  proper  provisions  shall be made so that the successors and
assigns of the Surviving  Corporation  shall assume all of the  obligations  set
forth in this Section.

                  (f)  The   provisions   of  this  Section  shall  survive  the
consummation  of the Merger at the  Effective  Time,  are intended to be for the
benefit  of, and shall be  enforceable  by, each of the  Indemnified  Parties as
intended  third  party  beneficiaries  and their  heirs and estates and shall be
binding on all successors and assigns of Parent and the Surviving Corporation.

                  6.15. Other Actions by the Company and Parent.

                  (a)  Rights.  Prior  to  the  Effective  Time,  the  board  of
directors  of the  Company  shall take all  necessary  action to ensure that the
representation and warranty in Section 5.1(s) is accurate.

                  (b) Antitakeover  Statutes.  If any Antitakeover Statute is or
may become  applicable to the Merger or the other  transactions  contemplated by
this Agreement,  the Stock Option Agreement,  or the Voting  Agreement,  each of
Parent and the Company and its board of directors shall grant such approvals and
take such  lawful  actions as are  necessary  so that such  transactions  may be
consummated  as  promptly  as  practicable  on the  terms  contemplated  by this
Agreement,  the Stock Option  Agreement or the Voting Agreement or by the Merger
and  otherwise  act to  eliminate  or minimize  the  effects of such  statute or
regulation on such transactions.

                  6.16.  Convertible Notes and Warrants.  Prior to the Effective
Time, the Company and Parent shall take all action  necessary to provide that on
and after the Effective Time the Convertible  Notes and Warrants  (including the
Note Warrants) will be convertible only into the Merger  Consideration,  subject
to any holder's right to hold securities through maturity.


                                      -57-

<PAGE>

                  6.17.  Funding  Mechanism.  Parent  and the  Company  agree as
follows.

                  (a)  Parent   agrees  to  cause  one  of  its   wholly   owned
subsidiaries (the "Lender") to make available as a loan to the Company,  subject
to the  provisions of Sections  6.17(b)  through (e), (i)  $15,000,000  (or such
lesser amount as the Company  elects to borrow) on September 1, 1999 (the "First
Loan"),  (ii) an  additional  $10,000,000  (or such lesser amount as the Company
elects  to  borrow)  on  November  1,  1999 (the  "Second  Loan"),  and (iii) an
additional  $10,000,000  (or such lesser amount as the Company elects to borrow)
on December 31, 1999 (the "Third Loan" and, collectively with the First Loan and
the Second Loan, the "Loans" and each such date,  with respect to the Loan to be
made on such date, the "Funding Date" for such Loan).

                  (b) The Lender  shall not be obligated to make any Loan if, on
or prior to the Funding Date for such Loan,  there has been a material breach by
the  Company of any  covenant or  agreement  of the  Company  contained  in this
Agreement (a "Breach").

                  (c) The Lender  shall not be obligated to make the Second Loan
or the Third Loan if, on or prior to the Funding Date for any such Loan:

                             (i) The  Stockholders  Meeting  (as  defined in the
         Merger Agreement) shall have been convened and the adoption referred to
         in  Section  7.1(a)  shall not have  been  obtained  thereat  or at any
         adjournment or postponement thereof (a "Vote Failure"), or

                             (ii)  The  Company  shall  have   terminated   this
         Agreement,  other than pursuant to Section  8.2(i),  8.2(iii) or 8.3(b)
         thereof (a "Company Termination").

                  (d) Unless the Lender and the Company  agree  otherwise,  each
Loan  will  mature  on a date  (which  date  shall  not be later  than the fifth
anniversary  of the Funding Date for such Loan)  determined in  accordance  with
Section  6.17(e).  The maturity  date of each Loan will  accelerate to the first
anniversary  of the Funding Date for such Loan in the event of a Breach,  a Vote
Failure or a Company Termination.


                                      -58-

<PAGE>

                  (e) The parties  agree that the terms and  conditions  of, and
the  definitive  documentation  concerning  the  Loans  (the  "Terms")  shall be
reasonable  and customary in light of the Company's  creditworthiness,  business
prospects and industry.  Parent and the Company agree to negotiate in good faith
concerning  the Terms and the  consents,  waivers  and  approvals  necessary  or
appropriate  in  connection  with the funding of the Loans on and subject to the
Terms (such consents, waivers and approvals, the "Waivers").

                  (f) The Terms and Waivers will be determined,  if possible, by
the mutual  agreement of Parent and the  Company.  If Parent and the Company are
unable to reach such an agreement by July 15, 1999, Parent and the Company shall
jointly  designate an individual or entity to determine no later than August 15,
1999 the Terms and Waivers after due  consideration of this Section 6.17 and any
submissions  the Company and Parent choose to make to such individual or entity,
and the  decision of such person or entity  shall be final and binding  upon the
parties. If Parent and the Company are unable to mutually agree on an individual
or entity by July 15, 1999, each shall choose an investment  banking firm (other
than Goldman,  Sachs & Co. and Lehman Brothers Inc.) and the two firms so chosen
shall  select  an  individual  or entity  which  shall  determine  the Terms and
Waivers,  which  determination  shall be final and  binding on the  parties.  If
either Parent or the Company  fails to select an investment  banking firm within
five  calendar  days of receipt of a notice  specifying  such  failure from such
other  party,  such other party may select an  individual  or entity which shall
determine the Terms and Waivers,  which determination shall be final and binding
on the parties.


                                   ARTICLE VII

                                   Conditions

                  7.1.  Conditions  to Each  Party's  Obligation  to Effect  the
Merger. The respective  obligation of each party to effect the Merger is subject
to the  satisfaction  or  waiver  at or  prior  to the  Closing  of  each of the
following conditions:

                  (a) Stockholder Approval.  This Agreement shall have been duly
adopted by holders of Shares constituting the Company Requisite Vote.

                                      -59-

<PAGE>

                  (b) Regulatory Consents.  The waiting period applicable to the
consummation  of the  Merger  under  the  HSR Act  shall  have  expired  or been
terminated.

                  (c) Litigation.  No court or Governmental  Entity of competent
jurisdiction shall have enacted,  issued, enforced or entered any statute, rule,
regulation,  judgment,  decree,  injunction or other order  (whether  temporary,
preliminary or permanent) that is in effect and restrains,  enjoins or otherwise
prohibits  consummation  of the  transactions  contemplated  by  this  Agreement
(collectively, an "Order"), and no Governmental Entity shall have instituted any
proceeding seeking any such Order.

                  (d) Registration  Statement.  The Registration Statement shall
have become  effective under the Securities Act and no stop order suspending the
effectiveness  of the  Registration  Statement  shall  have been  issued  and no
proceedings for that purpose shall have been initiated or be threatened  overtly
by the SEC.

                  7.2.  Conditions to  Obligations of Parent and Merger Sub. The
obligations  of Parent and  Merger Sub to effect the Merger are also  subject to
the  satisfaction  or  waiver  by  Parent  prior  to the  Effective  Time of the
following conditions:

                  (a)  Representations  and Warranties.  (i) The representations
and  warranties  of the  Company set forth in this  Agreement  shall be true and
correct in all material respects as of the date of this Agreement,  and (ii) the
representations  and warranties of the Company set forth in Sections 5.1(b), (c)
and (j) shall be true and  correct in all  material  respects  as of the Closing
Date as though made on and as of the Closing Date, and (iii) the representations
and  warranties  of the  Company  set forth in this  Agreement  (other  than the
representations  and warranties of the Company set forth in Sections 5.1(b), (c)
and (j)),  considered  without regard to any qualification by, or references to,
"material," "in all material  respects" or "Company  Material  Adverse  Effect,"
shall be true and correct as of the  Closing  Date as though made on the Closing
Date, except for such failures of such representations and warranties to be true
and  correct  as  do  not  arise  from  events,  occurrences  or  matters  that,
individually and in the aggregate, have not had and are not reasonably likely to
have a Company Material Adverse Effect, and (iv) Parent

                                      -60-

<PAGE>

shall have received a  certificate  signed on behalf of the Company by the chief
executive  officer and chief  financial  officer of the Company to the effect of
the foregoing.

                  (b)  Performance of  Obligations  of the Company.  The Company
shall have  performed in all material  respects all  obligations  required to be
performed by it under this Agreement and the Stock Option  Agreement at or prior
to the Closing  Date,  and Parent shall have  received a  certificate  signed on
behalf of the Company by the chief executive officer and chief financial officer
of the Company to such effect.

                  (c) Regulatory Consents. Other than the filing provided for in
Section 1.3, all filings  required to be made prior to the Effective Time by the
Company  or any of its  Subsidiaries,  with,  and all  consents,  approvals  and
authorizations  required  to be  obtained  prior to the  Effective  Time by, the
Company or any of its Subsidiaries  from, any Governmental  Entity in connection
with the execution and delivery of this  Agreement and the  consummation  of the
transactions contemplated hereby by the Company shall have been made or obtained
(as the case may be),  except  where the  failure to so make or obtain  will not
result in either a Company  Material Adverse Effect or a Parent Material Adverse
Effect or have a  significant  adverse  effect on the  benefits to Parent of the
transactions contemplated by this Agreement.

                  (d) Consents Under Agreements. The Company shall have obtained
the  consent or  approval of each  Person  whose  consent or  approval  shall be
required under each Contract to which the Company or any of its  Subsidiaries is
a party,  except those for which the failure to obtain such consent or approval,
individually  or in the aggregate,  is not  reasonably  likely to have a Company
Material Adverse Effect, is not reasonably likely to materially adversely affect
the ability of the Company to consummate the  transactions  contemplated by this
Agreement  and is not  reasonably  likely to impair the ability of the Parent or
any of their respective  affiliates,  following  consummation of the Merger,  to
conduct any material  business or operations in any jurisdiction  where they are
now being conducted.

                  (e) Tax  Opinion.  Parent  shall have  received the opinion of
Sullivan & Cromwell,  counsel to Parent,  dated the Closing  Date, to the effect
that the Merger will be

                                      -61-


<PAGE>

treated for Federal income tax purposes as a  reorganization  within the meaning
of  Section  368(a) of the Code,  and that each of  Parent,  Merger  Sub and the
Company  will be a party to that  reorganization  within the  meaning of Section
368(b)  of the  Code.  In  rendering  such  opinion,  such  counsel  may rely on
customary factual  representations  furnished by the Company,  Parent and Merger
Sub.

                  (f) Rights  Agreement.  All  necessary  action shall have been
taken to  ensure  that  neither  the  entering  into of this  Agreement  nor the
consummation of the Merger will cause the preferred stock purchase rights issued
pursuant to the Rights Agreement to become  exercisable,  cause Parent to become
an Acquiring Person (as such term is defined in the Rights  Agreement),  or give
rise to a  Distribution  Date or a Shares  Acquisition  Date (as such  terms are
defined in the Rights Agreement).

                  (g) Affiliates  Letters.  Parent shall have received a Company
Affiliates  Letter from each Person  identified  as an  affiliate of the Company
pursuant to Section 6.9(i) (other than  AstraZeneca plc) and shall have received
the AstraZeneca Affiliates Letter from AstraZeneca plc.

                  (h)  Accountants'  Letters.  Parent  shall have  received  the
letters described in Sections 6.7(b) and 6.7(c), unless the failure of Parent to
receive the letter  described in Section 6.7(c) has been  proximately  caused by
Parent's failure to issue or sell shares of Parent Common Stock.

                  7.3.  Conditions to Obligation of the Company.  The obligation
of the  Company  to effect the Merger is also  subject  to the  satisfaction  or
waiver by the Company prior to the Effective Time of the following conditions:

                  (a)  Representations  and Warranties.  (i) The representations
and  warranties  of Parent and Merger Sub set forth in this  Agreement  shall be
true and correct in all material respects as of the date of this Agreement,  and
(ii) the  representations  and  warranties of Parent and Merger Sub set forth in
Sections 5.2(c) and (d) shall be true and correct in all material respects as of
the Closing  Date as though made on and as of the  Closing  Date,  and (iii) the
representations  and  warranties  of  Parent  and  Merger  Sub set forth in this
Agreement (other than the representations and

                                      -62-

<PAGE>
warranties  of the  Company set forth in  Sections  5.2(c) and (d)),  considered
without regard to any  qualification  by, or reference to,  "material,"  "in all
material  respects"  or  "Parent  Material  Adverse  Effect,"  shall be true and
correct as of the Closing  Date as though made on the Closing  Date,  except for
such failures of such  representations  and warranties to be true and correct as
do not arise from events,  occurrences or matters that,  individually and in the
aggregate,  have not had and are not reasonably likely to have a Parent Material
Adverse Effect, and (iv) the Company shall have received a certificate signed on
behalf of Parent by the chief executive  officer and chief financial  officer of
Parent to the effect of the foregoing.

                  (b)  Performance of Obligations of Parent and Merger Sub. Each
of Parent and  Merger Sub shall have  performed  in all  material  respects  all
obligations  required to be performed by it under this  Agreement  and the Stock
Option  Agreement at or prior to the Closing  Date,  and the Company  shall have
received a certificate signed on behalf of Parent by the chief executive officer
and chief financial officer of Parent to such effect.

                  (c) Regulatory Consents. All filings required to be made prior
to the  Effective  Time by  Parent  or any of its  Subsidiaries,  with,  and all
consents,  approvals  and  authorizations  required to be obtained  prior to the
Effective  Time by, Parent or any of its  Subsidiaries  from,  any  Governmental
Entity in connection  with the execution and delivery of this  Agreement and the
consummation of the  transactions  contemplated  hereby by Parent and Merger Sub
shall have been made or obtained (as the case may be),  except where the failure
to so make or obtain will not result in either a Company Material Adverse Effect
or a Parent Material Adverse Effect.

                  (d) Tax Opinion.  The Company  shall have received the opinion
of Cooley  Godward LLP,  counsel to the Company,  dated the Closing Date, to the
effect  that the Merger will be treated  for  Federal  income tax  purposes as a
reorganization  within the meaning of Section  368(a) of the Code, and that each
of Parent,  Merger Sub and the  Company  will be a party to that  reorganization
within the meaning of Section  368(b) of the Code.  In rendering  such  opinion,
such  counsel may rely on  customary  factual  representations  furnished by the
Company, Parent and Merger Sub.


                                      -63-

<PAGE>

                  (e) NYSE  Listing.  The  shares of Parent  Common  Stock to be
delivered  pursuant to the Merger shall have been duly authorized for listing on
the NYSE, subject to official notice of issuance.

                  (f) Accountants'  Letters. The Company shall have received the
letter described in Section 6.7(b).


                                  ARTICLE VIII

                                   Termination

                  8.1.  Termination  by Mutual  Consent.  This  Agreement may be
terminated  and the Merger may be abandoned  at any time prior to the  Effective
Time,  whether  before or after the  approval  by  stockholders  of the  Company
referred to in Section 7.1(a), by mutual written consent of the Company,  Parent
and Merger Sub, by action of their respective boards of directors.

                  8.2.  Termination  by  Either  Parent  or  the  Company.  This
Agreement may be terminated and the Merger may be abandoned at any time prior to
the  Effective  Time by action of the board of directors of either Parent or the
Company if (i) the Merger shall not have been  consummated by November 30, 1999,
whether such date is before or after the date of approval by the stockholders of
the Company referred to in Section 7.1(a); provided,  however, that if a request
for  additional  information  is received from the United  States  Federal Trade
Commission or the Antitrust  Division of the United States Department of Justice
pursuant to the HSR Act or additional information is requested by a governmental
authority  (a  "Foreign  Authority")  pursuant  to the  antitrust,  competition,
foreign  investment,  or similar laws or any foreign  countries or supranational
commissions  or boards that  require  pre-merger  notifications  or filings with
respect to the Merger  (collectively,  "Foreign  Merger  Laws"),  then such date
shall be extended to the 30th day following  certification  by Parent and/or the
Company,  as applicable,  that Parent and/or the Company,  as  applicable,  have
substantially  complied  with such  request,  but in any  event  not later  than
January 31, 2000, (ii) the Stockholders Meeting shall have been convened and the
adoption  referred to in Section 7.1(a) shall not have been obtained  thereat or
at any  adjournment  or  postponement  thereof,  or (iii) any Order  permanently
restraining, enjoining or otherwise

                                      -64-

<PAGE>

prohibiting the Merger shall become final and non-appealable  (whether before or
after the adoption  referred to in Section  7.1(a));  provided that the right to
terminate this Agreement  pursuant to clause (i) above shall not be available to
any party that has breached in any material  respect its obligations  under this
Agreement in any manner that shall have been the proximate cause of, or resulted
in, the failure to  consummate  the Merger by the date referred to in clause (i)
of this Section 8.2 and,  provided,  further,  that the right to terminate  this
Agreement  pursuant to clause  (iii) above shall not be  available  to any party
that has breached its covenant to use  commercially  reasonable  best efforts to
prevent such Order from being  issued and to use  commercially  reasonable  best
efforts to cause such Order to be lifted.

                  8.3.  Termination  by  the  Company.  This  Agreement  may  be
terminated  and the Merger may be abandoned  at any time prior to the  Effective
Time,  whether  before or after the  approval  by  stockholders  of the  Company
referred  to in  Section  7.1(a),  by action of the  board of  directors  of the
Company:

                  (a) If (i) the Company is not in material breach of any of the
terms of this Agreement,  (ii) the board of directors of the Company  authorizes
the Company,  subject to complying  with the terms of this  Agreement,  to enter
into a binding written agreement  concerning a Superior Proposal and the Company
notifies  Parent in  writing,  that it intends to enter into such an  agreement,
attaching the most current  version of such agreement to such notice,  and (iii)
Parent does not make,  within  five  calendar  days of receipt of the  Company's
written notification of its intention to enter into such an agreement,  an offer
that  is at  least  as  favorable,  from  a  financial  point  of  view,  to the
stockholders  of the Company as the Superior  Proposal.  The Company  agrees (x)
that it will not enter into a binding  agreement  referred  to in clause (ii) of
the  previous  sentence  until at least  the  sixth  calendar  day  after it has
provided the written notice to Parent required  thereby and (y) to notify Parent
promptly if its intention to enter into a written agreement  referred to in such
notice shall change at any time after giving such notification.

                  (b) If there  has been a  material  breach by Parent or Merger
Sub of any representation,  warranty,  covenant or agreement of Parent or Merger
Sub contained in

                                      -65-

<PAGE>

this  Agreement  such that the  conditions in Section  7.3(a) or (b) will not be
satisfied (a "Terminating  Parent  Breach");  provided,  however,  that, if such
Terminating  Parent  Breach  is  curable  by  Parent  through  the  exercise  of
reasonable best efforts and such cure is reasonably likely to be completed prior
to the applicable date specified in Section  8.2(i),  then for so long as Parent
continues to exercise  reasonable best efforts to cure such  Terminating  Parent
Breach, the Company may not terminate this Agreement under this Section 8.3(b).

                  8.4.  Termination by Parent.  This Agreement may be terminated
and the  Merger may be  abandoned  at any time  prior to the  Effective  Time by
action of the board of directors of Parent:

                  (a) If the  board  of  directors  of the  Company  shall  have
withdrawn or adversely modified its approval or recommendation of this Agreement
or failed to reconfirm its recommendation of this Agreement within five calendar
days after a written request by Parent to do so.

                  (b) There has been a  material  breach by the  Company  of any
representation, warranty, covenant or agreement of the Company contained in this
Agreement  such  that  the  conditions  in  Section  7.2(a)  or (b)  will not be
satisfied (a "Terminating  Company Breach");  provided,  however,  that, if such
Terminating  Company  Breach is curable by the Company  through the  exercise of
reasonable best efforts and such cure is reasonably likely to be completed prior
to the  applicable  date  specified in Section  8.2(i),  then for so long as the
Company continues to exercise reasonable best efforts,  Parent may not terminate
this Agreement under this Section 8.4(b).

                  8.5. Effect of Termination and  Abandonment.  (a) In the event
of termination of this Agreement and the  abandonment of the Merger  pursuant to
this Article VIII, this Agreement (other than as set forth in Section 9.1) shall
become void and of no effect with no  liability  of any party  hereto (or any of
its directors,  officers,  employees,  agents,  legal and financial  advisors or
other representa tives) except pursuant to Section 6.13,  Section 6.17,  Section
8.5 and Article IX; provided, however, that except as otherwise provided herein,
no such  termination  shall relieve any party hereto of any liability or damages
resulting from any willful breach of this Agreement.

                                      -66-

<PAGE>

                  (b) In the event that (i) (A) a bona fide Acquisition Proposal
shall  have been made to the  Company or any of its  Subsidiaries  or any of its
stockholders  or any Person shall have  announced  an intention  (whether or not
conditional) to make an Acquisition  Proposal with respect to the Company or any
of its Subsidiaries, and on or following the date of this Agreement but prior to
the date of the Stockholders Meeting such Acquisition Proposal,  announcement or
intention is or becomes publicly known, and (B) on or following the date of this
Agreement  and  prior to the time such  Acquisition  Proposal,  announcement  or
intention is or becomes  publicly  known,  the  occurrence of a Parent  Material
Adverse Effect shall not have become publicly known, and (C) on or following the
date on which such Acquisition Proposal, announcement or intention is or becomes
publicly  known,  this  Agreement is  terminated by either Parent or the Company
pursuant to Section  8.2(ii),  or (ii) this  Agreement is terminated  (x) by the
Company  pursuant to Section 8.3(a) or (y) by Parent pursuant to Section 8.4(a),
then, subject to Section 8.5(c), the Company (p) shall promptly, but in no event
later than two days  after the date of such  termination  (except  as  otherwise
provided  in the  proviso to this  sentence),  pay Parent a  termination  fee of
$16,900,000  payable by wire transfer of same day funds, and (q) shall promptly,
but in no event later than two  calendar  days after  being  notified of such by
Parent,  pay all of the charges and expenses incurred by Parent or Merger Sub in
connection  with this  Agreement,  the Stock  Option  Agreement  and the  Voting
Agreement and the transactions  contemplated by this Agreement, the Stock Option
Agreement and the Voting  Agreement,  up to a maximum of  $5,000,000;  provided,
however, that no termination fee shall be payable to Parent by reason of Section
8.5(b)(i) or a termination of this  Agreement  pursuant to Section 8.3(a) unless
and until (I) any person or entity  (other than Parent) (an  "Acquiring  Party")
has acquired,  by purchase,  merger,  consolidation,  sale,  assignment,  lease,
transfer or otherwise,  in one transaction or any related series of transactions
within 18 months of such  termination,  a majority  of the  voting  power of the
outstanding  securities  of the  Company  or (II) there has been  consummated  a
merger, consolidation or similar business combination between the Company and an
Acquiring Party or an affiliate thereof as a result of which the stockholders of
the Company  immediately prior to the transaction do not own at least 75% of the
surviving entity. The Company acknowledges that the agreements contained in this
Section 8.5(b) are an integral part of the  transactions  con-

                                      -67-
<PAGE>

templated by this  Agreement,  and that,  without these  agreements,  Parent and
Merger  Sub would not enter into this  Agreement;  accordingly,  if the  Company
fails to promptly pay the amount due pursuant to this  Section  8.5(b),  and, in
order to obtain  such  payment,  Parent or Merger  Sub  commences  a suit  which
results  in a  judgment  against  the  Company  for the fee  set  forth  in this
paragraph  (b),  the  Company  shall pay to  Parent or Merger  Sub its costs and
expenses (including attorneys' fees) in connection with such suit, together with
interest on the amount of the fee at the prime rate of Citibank,  N.A. in effect
on the date such payment was required to be made.

                  (c) Parent  agrees  that the payment  provided  for in Section
8.5(b) shall be the sole and exclusive remedy of Parent upon termination of this
Agreement  pursuant to Section  8.3(a) or 8.4(a) or (c), as the case may be, and
such remedy  shall be limited to the  aggregate of the sums  stipulated  in such
Section 8.5(b);  provided,  however, that nothing herein shall relieve any party
from liability for the willful breach of any of its representations, warranties,
covenants  or  agreements  set forth in this  Agreement.  In no event  shall the
Company be required to pay to Parent more than one  termination  fee pursuant to
Section 8.5(b)(p).  Notwithstanding any other provision of this Agreement or the
Stock  Option  Agreement,  any  termination  fee  required  to be paid to Parent
pursuant  to  Section  8.5(b)(p)  shall be reduced  (but not below  zero) to the
extent  necessary so that the sum of the portion of any termination fee actually
paid to Parent,  the  aggregate of all  Cancellation  Amounts (as defined in the
Stock Option  Agreement) paid to Parent  pursuant to the Stock Option  Agreement
and the proceeds  actually received by Parent as the result of selling Shares to
a third party which acquires more than 50% of the Company's  outstanding  voting
securities  (other than the Company or any of its  affiliates)  shall not exceed
$21,900,000. In no event shall (i) the sum of the portion of any termination fee
actually paid to Parent and the cash proceeds actually received by Parent as the
result of selling  Shares to a third party which  acquires  more than 50% of the
Company's  outstanding  voting  securities (other than the Company or any of its
affiliates)  exceed  $21,900,000,  or  (ii)  the  sum  of  the  portion  of  any
termination fee actually paid to Parent, the aggregate Cancellation Amounts paid
to parent pursuant to the Stock Option Agreement and the cash proceeds  actually
received by parent as the result of selling Shares to a third party

                                      -68-


<PAGE>

which  acquires  more than 50% of the  Company'  outstanding  voting  securities
(other than the Company or any of its affiliates) exceed $21,900,000.


                                   ARTICLE IX

                            Miscellaneous and General

                  9.1.  Survival.  This  Article  IX and the  agreements  of the
Company,  Parent and  Merger Sub  contained  in  Articles  I, II, III and IV and
Sections 6.7 (Taxation and Accounting),  6.12 (Benefits),  6.13 (Expenses), 6.14
and  (Indemnification;  Directors'  and Officers'  Insurance)  shall survive the
consummation  of the Merger.  This Article IX and the agreements of the Company,
Parent  and Merger  Sub  contained  in Section  6.13  (Expenses),  Section  6.17
(Funding  Mechanism)  and Section 8.5 (Effect of  Termination  and  Abandonment)
shall survive the  termination  of this  Agreement.  All other  representations,
warranties,  agreements  and covenants in this  Agreement  shall not survive the
consummation of the Merger or the termination of this Agreement.

                  9.2.  Modification or Amendment.  Subject to the provisions of
applicable  law, at any time prior to the Effective Time, the parties hereto may
modify or amend this Agreement,  by written agreement  executed and delivered by
duly authorized officers of the respective parties.

                  9.3.  Waiver  of  Conditions.  The  conditions  to each of the
parties'  obligations  to consummate the Merger are for the sole benefit of such
party  and may be  waived  by  such  party  in  whole  or in part to the  extent
permitted by applicable law.

                  9.4.  Counterparts.  This  Agreement  may be  executed  in any
number of  counterparts,  each such  counterpart  being deemed to be an original
instrument,  and all  such  counterparts  shall  together  constitute  the  same
agreement.

                  9.5.  GOVERNING LAW AND VENUE;  WAIVER OF JURY TRIAL. (a) THIS
AGREEMENT  SHALL  BE  DEEMED  TO BE  MADE  IN  AND  IN  ALL  RESPECTS  SHALL  BE
INTERPRETED,  CONSTRUED AND GOVERNED BY AND IN  ACCORDANCE  WITH THE LAWS OF THE
STATE OF NEW YORK WITHOUT REGARD TO THE CONFLICT OF LAW PRINCIPLES THEREOF.  The
parties hereby irrevocably submit to the

                                      -69-


<PAGE>

jurisdiction  of the courts of the State of New York and the  Federal  courts of
the United States of America  located in the Borough of  Manhattan,  The City of
New  York  solely  in  respect  of the  interpretation  and  enforcement  of the
provisions  of this  Agreement,  the  Stock  Option  Agreement  and  the  Voting
Agreement and of the documents  referred to in this Agreement,  the Stock Option
Agreement  and  the  Voting  Agreement,  and  in  respect  of  the  transactions
contemplated hereby and thereby, and hereby waive, and agree not to assert, as a
defense in any action,  suit or proceeding for the interpretation or enforcement
hereof or of any such  document,  that it is not  subject  thereto  or that such
action,  suit or proceeding  may not be brought or is not  maintainable  in said
courts or that the venue thereof may not be appropriate or that this  Agreement,
the Stock Option  Agreement or the Voting Agreement or any such document may not
be enforced in or by such courts,  and the parties hereto irrevocably agree that
all  claims  with  respect  to such  action  or  proceeding  shall be heard  and
determined in such a New York State or Federal court. The parties hereby consent
to and grant any such court  jurisdiction  over the person of such  parties  and
over the subject  matter of such  dispute  and agree that  mailing of process or
other  papers in  connection  with any such action or  proceeding  in the manner
provided  in Section  9.6 or in such other  manner as may be  permitted  by law,
shall be valid and sufficient service thereof.

                  (b) EACH PARTY  ACKNOWLEDGES  AND AGREES THAT ANY  CONTROVERSY
WHICH MAY ARISE UNDER THIS AGREEMENT,  THE STOCK OPTION  AGREEMENT OR THE VOTING
AGREEMENT IS LIKELY TO INVOLVE  COMPLICATED AND DIFFICULT ISSUES,  AND THEREFORE
EACH SUCH PARTY HEREBY  IRREVOCABLY  AND  UNCONDITIONALLY  WAIVES ANY RIGHT SUCH
PARTY  MAY HAVE TO A TRIAL BY JURY IN  RESPECT  OF ANY  LITIGATION  DIRECTLY  OR
INDIRECTLY  ARISING  OUT OF OR  RELATING  TO THIS  AGREEMENT,  THE STOCK  OPTION
AGREEMENT OR THE VOTING AGREEMENT,  OR THE TRANSACTIONS  CONTEMPLATED  HEREBY OR
THEREBY. EACH PARTY CERTIFIES AND ACKNOWLEDGES THAT (I) NO REPRESENTATIVE, AGENT
OR ATTORNEY OF ANY OTHER PARTY HAS  REPRESENTED,  EXPRESSLY OR  OTHERWISE,  THAT
SUCH OTHER  PARTY  WOULD NOT,  IN THE EVENT OF  LITIGATION,  SEEK TO ENFORCE THE
FOREGOING  WAIVER,  (II) EACH SUCH  PARTY  UNDERSTANDS  AND HAS  CONSIDERED  THE
IMPLICATIONS   OF  THIS  WAIVER,   (III)  EACH  SUCH  PARTY  MAKES  THIS  WAIVER
VOLUNTARILY,  AND (IV)  EACH  SUCH  PARTY HAS BEEN  INDUCED  TO ENTER  INTO THIS
AGREEMENT  OR THE STOCK OPTION  AGREEMENT  BY,  AMONG OTHER  THINGS,  THE MUTUAL
WAIVERS AND CERTIFICATIONS IN THIS SECTION 9.5.

                                      -70-

<PAGE>

                  9.6.  Notices.  Any  notice,  request,  instruction  or  other
document to be given  hereunder  by any party to the others  shall be in writing
and  delivered  personally  or sent by  registered  or certified  mail,  postage
prepaid, or by facsimile:

                  if to Parent or Merger Sub

                  Richard T. Collier
                  Pharmacia & Upjohn, Inc.
                  95 Corporate Drive
                  Bridgewater, New Jersey 08807
                  fax: (908) 306-4489

                  with copies to:

                  Neil T. Anderson
                  Matthew G. Hurd
                  Martin J. Travers
                  Sullivan & Cromwell
                  125 Broad Street
                  New York, NY 10004
                  fax:  (212) 558-3588

                  if to the Company

                  Bruce E. MacMillan
                  SUGEN, Inc.
                  230 East Grand Avenue
                  South San Francisco, CA 94080
                  fax: (650) 553-8342

                  with  copies to:

                  Alan C. Mendelson
                  Suzanne Sawochka Hooper
                  Gianna M. Bosko
                  Cooley Godward LLP
                  5 Palo Alto Square
                  3000 El Camino Real
                  Palo Alto, California 94306
                  fax:  (650) 857-0663

or to such other  persons or  addresses as may be  designated  in writing by the
party to receive such notice as provided above.


                                      -71-

<PAGE>

                  9.7. Entire Agreement.  This Agreement (including any exhibits
and schedules hereto), the Stock Option Agreement,  the Company  Confidentiality
Agreement  and  the  Parent  Confidentiality  Agreement  constitute  the  entire
agreement,   and   supersede   all  other  prior   agreements,   understandings,
representations  and warranties both written and oral,  among the parties,  with
respect to the subject matter hereof.

                  9.8.  No Third  Party  Beneficiaries.  Except as  provided  in
Section  6.14  (Indemnification;   Directors'  and  Officers'  Insurance),  this
Agreement  is not  intended  to confer  upon any Person  other than the  parties
hereto any rights or remedies hereunder.

                  9.9.  Obligations of Parent and of the Company.  Whenever this
Agreement  requires a Subsidiary of Parent to take any action,  such requirement
shall be deemed to  include an  undertaking  on the part of Parent to cause such
Subsidiary to take such action. Whenever this Agreement requires a Subsidiary of
the Company to take any action,  such requirement  shall be deemed to include an
undertaking  on the part of the  Company to cause such  Subsidiary  to take such
action and, after the Effective  Time, on the part of the Surviving  Corporation
to cause such Subsidiary to take such action.

                  9.10. Severability.  The provisions of this Agreement shall be
deemed severable and the invalidity or  unenforceability  of any provision shall
not affect the validity or enforceability of the other provisions hereof. If any
provision of this  Agreement,  or the  application  thereof to any Person or any
circumstance,  is  invalid  or  unenforceable,  (a)  a  suitable  and  equitable
provision shall be substituted  therefor in order to carry out, so far as may be
valid and  enforceable,  the intent and purpose of such invalid or unenforceable
provision and (b) the remainder of this  Agreement and the  application  of such
provision  to other  Persons  or  circumstances  shall not be  affected  by such
invalidity or  unenforceability,  nor shall such invalidity or  unenforceability
affect the validity or  enforceability  of such  provision,  or the  application
thereof, in any other jurisdiction.

                  9.11.   Specific   Performance.   The   parties   hereto  each
acknowledge  that, in view of the uniqueness of the subject  matter hereof,  the
parties  hereto  would not have an adequate  remedy at law for money  damages if
this Agreement

                                      -72-

<PAGE>

were not performed in accordance  with its terms,  and therefore  agree that the
parties hereto shall be entitled to specific  enforcement of the terms hereof in
addition to any other remedy to which the parties  hereto may be entitled at law
or in equity.

                  9.12.  Interpretation.  The  table of  contents  and  headings
herein are for  convenience of reference  only, do not  constitute  part of this
Agreement  and  shall  not be deemed  to limit or  otherwise  affect  any of the
provisions  hereof.  Where a reference  in this  Agreement is made to a Section,
Schedule  or  Exhibit,  such  reference  shall be to a Section of or Schedule or
Exhibit  to this  Agreement  unless  otherwise  indicated.  Whenever  the  words
"include,"  "includes" or "including" are used in this Agreement,  they shall be
deemed to be followed by the words "without limitation."

                  9.13.  Assignment.  This Agreement  shall not be assignable by
operation of law or otherwise;  provided, however, that Parent may designate, by
written notice to the Company,  another  wholly owned direct  subsidiary to be a
Constituent  Corporation  in lieu of Merger  Sub,  in the  event of  which,  all
references  herein  to  Merger  Sub shall be  deemed  references  to such  other
subsidiary  except  that all  representations  and  warranties  made herein with
respect  to  Merger  Sub as of the  date  of  this  Agreement  shall  be  deemed
representations  and warranties made with respect to such other subsidiary as of
the date of such designation.  Any purported assignment made in contravention of
this Agreement shall be null and void.

                  9.14.  Captions.  The Article,  Section and paragraph captions
herein are for  convenience of reference only and do not constitute part of this
Agreement  and  shall  not be deemed  to limit or  otherwise  affect  any of the
provisions hereof.

                                      -73-

<PAGE>

                  IN WITNESS WHEREOF,  this Agreement has been duly executed and
delivered  by duly  authorized  officers  of the  parties  hereto as of the date
hereof.


                                      SUGEN, INC.



                                      By: /s/ Stephen Evans-Freke
                                          ---------------------------------
                                          Name:   Stephen Evans-Freke
                                          Title:  Chairman of the Board and
                                                    Chief Executive Officer


                                      PHARMACIA & UPJOHN, INC.



                                      By: /s/ Christopher J. Coughlin
                                          ---------------------------------
                                          Name:   Christopher J. Coughlin
                                          Title:  Executive Vice President


                                      UNIVERSITY ACQUISITION CORP.



                                      By: /s/ Mats Petterson
                                          ---------------------------------
                                          Name:   Mats Petterson
                                          Title:  Senior Vice President



<PAGE>


                                                                    EXHIBIT AZ-1


                         (AstraZeneca Affiliates Letter)


TO PHARMACIA & UPJOHN:

                  Re:        Agreement and Plan of Merger

Ladies and Gentlemen:

                  The  undersigned  has been advised that the undersigned may be
considered an  "affiliate"  of SUGEN,  Inc. (the  "Company") for purposes of (i)
Rule 145 of the General Rules and Regulations  (the "Rules and  Regulations") of
the Securities and Exchange  Commission  (the "SEC") under the Securities Act of
1933,  as amended (the  "Securities  Act"),  and/or (ii) SEC  Accounting  Series
Releases 130 and 135, as amended.  Pursuant to the Agreement and Plan of Merger,
dated as of June 15, 1999 (the "Merger Agreement"), among the Company, Pharmacia
& Upjohn, Inc.  ("Parent") and University  Acquisition Corp. ("Merger Sub"), the
undersigned  may  receive  shares of common  stock of Parent (the  "Shares")  in
exchange for the shares of stock of the Company owned by the  undersigned at the
effective  date  of  the  merger  provided  for  in the  Merger  Agreement  (the
"Merger").

                  The  undersigned  represents and warrants to, and agrees with,
Parent that:

                  A. The undersigned  will not make any sale,  transfer or other
         disposition of the undersigned's  Shares in violation of the Securities
         Act or the Rules and Regulations.

                  B. The  undersigned  has been advised that the offering,  sale
         and  delivery  of the Shares to the  undersigned  in the Merger will be
         registered under the Securities Act on a Registration Statement on Form
         S-4. The undersigned has also been advised,  however,  that,  since the
         undersigned may be considered an "affiliate" of the Company at the time
         the Merger Agreement is submitted for a vote of the stockholders of the
         Company,  any public  offering or sale by the undersigned of any of the
         Shares  will,  under  current  law,  require  either  (i)  the  further
         registration  under the  Securities Act of the Shares to be offered and
         sold, (ii)  compliance by the  undersigned  with SEC Rule 145 under the
         Securities  Act in  connection  with  such  offer and sale or (iii) the
         availability of another exemption

                                     AZ-1-1

<PAGE>

         from  registration  of such Shares  under the  Securities  Act for such
         offer and sale.

                  C. The  undersigned  has carefully read this letter  agreement
         and the Merger Agreement and has discussed their requirements and other
         applicable limitations upon the undersigned's ability to sell, transfer
         or otherwise  dispose of the Shares, to the extent the undersigned felt
         necessary, with the undersigned's counsel or counsel for the Company.

                  D. The  undersigned  has been informed by the Company that the
         Shares  have  not  been   registered   under  the  Securities  Act  for
         distribution by the undersigned and that the Shares must be held by the
         undersigned  for at least two years  unless (i) such  Shares  have been
         registered for  distribution  under the Securities  Act, (ii) a sale of
         the Shares is made in conformity with the volume and other  limitations
         of SEC Rule 145 under the  Securities  Act or (iii) in the  opinion  of
         counsel  reasonably  acceptable to Parent,  some other  exemption  from
         registration  under the Securities Act is available with respect to any
         such proposed sale, transfer or other disposition of the Shares.

                  E.  The  undersigned  understands  that  Parent  is  under  no
         obligation to register the sale,  transfer or other  disposition of the
         Shares by the  undersigned  or on behalf of the  undersigned  under the
         Securities  Act or to take any other action  necessary in order to make
         compliance  with an exemption from such  registration  available to the
         undersigned.

                  F.  The  undersigned   also  understands  that  stop  transfer
         instructions  will be given to all  transfer  agents for the Shares and
         that there will be placed on the  certificates for the Shares issued to
         the undersigned,  or any replacements or substitutes therefor, a legend
         stating in substance:

                             "The shares  represented by this  certificate  were
                  issued in a transaction to which Rule 145 under the Securities
                  Act  of  1933  applies.   The  shares   represented   by  this
                  certificate  may only be  transferred  in accordance  with the
                  terms of an  agreement,  dated  June  15,  1999,  between  the
                  registered

                                     AZ-1-2


<PAGE>



                  holder hereof and the issuer,  a copy of which  agreement will
                  be mailed to the holder hereof without  charge  promptly after
                  receipt by the issuer of a written request therefor."

                  G. The undersigned also understands  that, unless the transfer
         of the  undersigned's  Shares has been registered  under the Securities
         Act or the undersigned  represents and warrants to Parent that any such
         transfer has been made in  conformity  with the  provisions of SEC Rule
         145,  Parent shall have the right to place the following  legend on the
         certificates issued to any transferee of such Shares:

                             "The shares  represented by this  certificate  have
                  not been registered  under the Securities Act of 1933 and were
                  acquired   from  a  person  who  received  such  shares  in  a
                  transaction to which Rule 145 under the Securities Act of 1933
                  applies.  The  shares may not be sold,  pledged  or  otherwise
                  transferred  except in accordance  with an exemption  from the
                  registration requirements of the Securities Act of 1933."

                  It is  understood  and agreed  that the  legends  set forth in
paragraphs  F and G  above  shall  be  removed  by the  delivery  of  substitute
certificates  without  such legend if the  undersigned  shall have  delivered to
Parent a copy of a letter from the staff of the SEC, or an opinion of counsel in
form and substance  reasonably  satisfactory to Parent,  to the effect that such
legend is not  required  for purposes of the  Securities  Act. In addition,  the
legend  referred to in paragraph F above will be removed upon written request at
any time more than two years after the effective date of the Merger.

                  The  undersigned  further  represents  to and  covenants  with
Parent that the  undersigned  will not,  within the 30 days prior to the Closing
Date (as defined in the Merger Agreement),  sell,  transfer or otherwise dispose
of any shares of stock of the Company except  pursuant to and upon  consummation
of the Merger,  and that the  undersigned  will not sell,  transfer or otherwise
dispose of any Shares (whether or not acquired by the undersigned in the Merger)
until  after  such  time as  results  covering  at  least  30  days of  combined
operations of the Company and Parent have been

                                     AZ-1-3

<PAGE>


published  by Parent,  in the form of a quarterly  earnings  press  release,  an
effective registration statement filed with the SEC, a report filed with the SEC
on Form  10-K,  10-Q or 8-K or any  other  public  filing or  announcement  that
includes such  combined  results of  operations.  Furthermore,  the  undersigned
understands that the Company and Parent will give stop transfer  instructions to
their respective transfer agents in order to prevent the breach of the covenants
made by the undersigned in this paragraph.

                  Execution of this letter should not be considered an admission
on the part of the undersigned  that it is an "affiliate" of the Company,  nor a
waiver  of any  rights  that  the  undersigned  may have to  object  at any time
following the date hereof to any claim that the undersigned is an "affiliate" of
the Company.

                  This  letter and that  certain  Voting  Agreement  between the
undersigned and Parent constitutes the complete understanding between Parent and
the undersigned  concerning the subject matter hereof. The surviving corporation
is expressly  intended to be a beneficiary of this letter agreement.  Any notice
required  to be sent to any  party  hereunder  shall  be sent by  registered  or
certified mail, return receipt  requested,  using the addresses set forth herein
or such other  address as shall be  furnished  in writing by the  parties.  This
letter shall be governed by, and construed and  interpreted in accordance  with,
the  laws of the  State  of New  York  applicable  to  contracts  made and to be
performed within such state.

                                Very truly yours,

                                ZENECA LIMITED


                                _____________________________________


ACCEPTED:

PHARMACIA & UPJOHN, INC.



By: _____________________________

                                     AZ-1-4


<PAGE>


                                                                     EXHIBIT A-1


                           (Company Affiliates Letter)


TO PHARMACIA & UPJOHN, INC.:

                  Re:        Agreement and Plan of Merger

Ladies and Gentlemen:

                  The  undersigned  has been advised that the undersigned may be
considered an  "affiliate"  of SUGEN,  Inc. (the  "Company") for purposes of (i)
Rule 145 of the General Rules and Regulations  (the "Rules and  Regulations") of
the Securities and Exchange  Commission  (the "SEC") under the Securities Act of
1933,  as amended (the  "Securities  Act"),  and/or (ii) SEC  Accounting  Series
Releases 130 and 135, as amended.  Pursuant to the Agreement and Plan of Merger,
dated as of June 15, 1999 (the "Merger Agreement"), among the Company, Pharmacia
& Upjohn, Inc.  ("Parent") and University  Acquisition Corp. ("Merger Sub"), the
undersigned  may  receive  shares of common  stock of Parent (the  "Shares")  in
exchange for the shares of stock of the Company owned by the  undersigned at the
effective  date  of  the  merger  provided  for  in the  Merger  Agreement  (the
"Merger").

                  The  undersigned  represents and warrants to, and agrees with,
Parent that:

                  A. The undersigned  will not make any sale,  transfer or other
         disposition of the undersigned's  Shares in violation of the Securities
         Act or the Rules and Regulations.

                  B. The  undersigned  has been advised that the offering,  sale
         and  delivery  of the Shares to the  undersigned  in the Merger will be
         registered under the Securities Act on a Registration Statement on Form
         S-4. The undersigned has also been advised,  however,  that,  since the
         undersigned may be considered an "affiliate" of the Company at the time
         the Merger Agreement is submitted for a vote of the stockholders of the
         Company,  any public  offering or sale by the undersigned of any of the
         Shares  will,  under  current  law,  require  either  (i)  the  further
         registration  under the  Securities Act of the Shares to be offered and
         sold, (ii)  compliance by the  undersigned  with SEC Rule 145 under the
         Securities  Act in  connection  with  such  offer and sale or (iii) the
         availability of another exemption

                                      A-1-1

<PAGE>

         from  registration  of such Shares  under the  Securities  Act for such
         offer and sale.

                  C. The  undersigned  has carefully read this letter  agreement
         and the Merger Agreement and has discussed their requirements and other
         applicable limitations upon the undersigned's ability to sell, transfer
         or otherwise  dispose of the Shares, to the extent the undersigned felt
         necessary, with the undersigned's counsel or counsel for the Company.

                  D. The  undersigned  has been informed by the Company that the
         Shares  have  not  been   registered   under  the  Securities  Act  for
         distribution by the undersigned and that the Shares must be held by the
         undersigned  for at least two years  unless (i) such  Shares  have been
         registered for  distribution  under the Securities  Act, (ii) a sale of
         the Shares is made in conformity with the volume and other  limitations
         of SEC Rule 145 under the  Securities  Act or (iii) in the  opinion  of
         counsel  reasonably  acceptable to Parent,  some other  exemption  from
         registration  under the Securities Act is available with respect to any
         such proposed sale, transfer or other disposition of the Shares.

                  E.  The  undersigned  understands  that  Parent  is  under  no
         obligation to register the sale,  transfer or other  disposition of the
         Shares by the  undersigned  or on behalf of the  undersigned  under the
         Securities  Act or to take any other action  necessary in order to make
         compliance  with an exemption from such  registration  available to the
         undersigned.

                  F.  The  undersigned   also  understands  that  stop  transfer
         instructions  will be given to all  transfer  agents for the Shares and
         that there will be placed on the  certificates for the Shares issued to
         the undersigned,  or any replacements or substitutes therefor, a legend
         stating in substance:

                             "The shares  represented by this  certificate  were
                  issued in a transaction to which Rule 145 under the Securities
                  Act  of  1933  applies.   The  shares   represented   by  this
                  certificate  may only be  transferred  in accordance  with the
                  terms of an  agreement,  dated  June  15,  1999,  between  the
                  registered

                                      A-1-2

<PAGE>


                  holder hereof and the issuer,  a copy of which  agreement will
                  be mailed to the holder hereof without  charge  promptly after
                  receipt by the issuer of a written request therefor."

                  G. The undersigned also understands  that, unless the transfer
         of the  undersigned's  Shares has been registered  under the Securities
         Act or the undersigned  represents and warrants to Parent that any such
         transfer has been made in  conformity  with the  provisions of SEC Rule
         145,  Parent shall have the right to place the following  legend on the
         certificates issued to any transferee of such Shares:

                             "The shares  represented by this  certificate  have
                  not been registered  under the Securities Act of 1933 and were
                  acquired   from  a  person  who  received  such  shares  in  a
                  transaction to which Rule 145 under the Securities Act of 1933
                  applies.  The  shares may not be sold,  pledged  or  otherwise
                  transferred  except in accordance  with an exemption  from the
                  registration requirements of the Securities Act of 1933."

                  It is  understood  and agreed  that the  legends  set forth in
paragraphs  F and G  above  shall  be  removed  by the  delivery  of  substitute
certificates  without  such legend if the  undersigned  shall have  delivered to
Parent a copy of a letter from the staff of the SEC, or an opinion of counsel in
form and substance  reasonably  satisfactory to Parent,  to the effect that such
legend is not  required  for purposes of the  Securities  Act. In addition,  the
legend  referred to in Paragraph F above will be removed upon written request at
any time more than two years after the effective date of the Merger.

                  The  undersigned  further  represents  to and  covenants  with
Parent that the  undersigned  will not,  within the 30 days prior to the Closing
Date (as defined in the Merger Agreement),  sell,  transfer or otherwise dispose
of any shares of stock of the Company except  pursuant to and upon  consummation
of the Merger,  and that the  undersigned  will not sell,  transfer or otherwise
dispose of any Shares (whether or not acquired by the undersigned in the Merger)
until  after  such  time as  results  covering  at  least  30  days of  combined
operations of the Company and Parent have been

                                      A-1-3

<PAGE>

published  by Parent,  in the form of a quarterly  earnings  press  release,  an
effective registration statement filed with the SEC, a report filed with the SEC
on Form  10-K,  10-Q or 8-K or any  other  public  filing or  announcement  that
includes such  combined  results of  operations.  Furthermore,  the  undersigned
understands that the Company and Parent will give stop transfer  instructions to
their respective transfer agents in order to prevent the breach of the covenants
made by the undersigned in this paragraph.

                  Execution of this letter should not be considered an admission
on the part of the undersigned  that it is an "affiliate" of the Company,  nor a
waiver  of any  rights  that  the  undersigned  may have to  object  at any time
following the date hereof to any claim that the undersigned is an "affiliate" of
the Company.

                  This letter  constitutes  the complete  understanding  between
Parent and the undersigned  concerning the subject matter hereof.  The surviving
corporation is expressly  intended to be a beneficiary of this letter agreement.
Any  notice  required  to be  sent  to any  party  hereunder  shall  be  sent by
registered or certified mail, return receipt requested,  using the addresses set
forth  herein or such  other  address  as shall be  furnished  in writing by the
parties.  This letter shall be governed by, and  construed  and  interpreted  in
accordance  with, the laws of the State of New York applicable to contracts made
and to be performed within such state.

                                          Very truly yours,



                                          _________________________________
                                                (Name of Affiliate)

ACCEPTED:

PHARMACIA & UPJOHN, INC.



By: _________________________________



                                      A-1-4
<PAGE>


                                                                       ANNEX B-1

TO PHARMACIA & UPJOHN, INC.:


Ladies and Gentlemen:

                  I have  been  advised  that as of the  date  hereof,  I may be
deemed to be an "affiliate" of Pharmacia & Upjohn,  Inc., a Delaware corporation
("Parent"),  as such term (i) is defined for purposes of paragraphs  (c) and (d)
of  Rule  145 of the  Rules  and  Regulations  of the  Securities  and  Exchange
Commission (the "Commission")  under the Securities Act of 1933, as amended,  or
(ii) is used in and for purposes of Accounting  Series  Releases 130 and 135, as
amended,  of the Commission.  Pursuant to the terms of the Agreement and Plan of
Merger  (the  "Merger  Agreement"),  dated  as of June  15,  1999,  as it may be
amended,  supplemented  or modified from time to time,  among SUGEN,  a Delaware
corporation  (the  "Company"),  Parent,  and  University  Acquisition  Corp.,  a
Delaware  corporation  to be  formed  as a wholly  owned  subsidiary  of  Parent
("Merger  Sub"),  Merger  Sub will be  merged  with and  into the  Company  (the
"Merger").  Capitalized  terms used herein but not defined herein shall have the
meanings ascribed to such terms in the Merger Agreement.

                  I further  understand  that the  Merger  will be  treated  for
financial  accounting  purposes as a "pooling of interests"  in accordance  with
generally  accepted  accounting  principles and that the Staff of the Commission
has issued certain  guidelines  that should be followed to ensure the pooling of
the entities.

                  In  consideration  of the  agreements  contained  herein,  the
Company's  reliance on this letter in connection  with the  consummation  of the
Merger  and  for  other  good  and  valuable  consideration,   the  receipt  and
sufficiency of which are hereby  acknowledged,  I hereby represent,  warrant and
agree  that I will not make any  sale,  transfer,  or other  disposition  of any
shares of Common  Stock,  par value $0.01 per share of Parent  during the period
beginning 30 days prior to the Closing Date (as defined in the Merger Agreement)
and  ending  after such time as results  covering  at least 30 days of  combined
operations of the Company and Parent have been published by Parent,  in the form
of a quarterly earnings report, an effective registration

                                      B-1-1

<PAGE>

                                                                       ANNEX B-1

statement  filed with the  Commission,  a report to the Commission on Form 10-K,
10-Q or 8-K, or any other public  filing or  announcement  which  includes  such
combined results of operations.

                  Execution of this letter should not be considered an admission
on my  part  that I am an  "affiliate"  of  Parent  as  described  in the  first
paragraph of this  letter,  or as a waiver of any rights I may have to object to
any claim that I am such an affiliate on or after the date of this letter.

                  This letter agreement  constitutes the complete  understanding
between the Company and me  concerning  the subject  matter  hereof.  Any notice
required to be sent to either party  hereunder  shall be sent by  registered  or
certified mail, return receipt  requested,  using the addresses set forth herein
or such other  address as shall be  furnished  in writing by the  parties.  This
letter  agreement  shall  be  governed  by  and  construed  and  interpreted  in
accordance with, the laws of the State of New York.

                  If you are in agreement with the foregoing, please so indicate
by signing  below and  returning  a copy of this letter to the  undersigned,  at
which time this letter shall become a binding agreement between us.

                                      Very truly yours,


                                      _______________________________
                                      Name:
                                      Address:

Accepted this ____ day of ___________, 1999.

PHARMACIA & UPJOHN, INC.


By:______________________
   Name:
   Title:


                                      B-1-2




                                                                     EXHIBIT 2.2



                                                                  EXECUTION COPY




                             STOCK OPTION AGREEMENT


                  STOCK  OPTION  AGREEMENT,  dated  as of  June  15,  1999  (the
"Agreement"),  between  Pharmacia & Upjohn,  Inc., a Delaware  corporation  (the
"Grantee"), and SUGEN, Inc., a Delaware corporation (the "Grantor").

                  WHEREAS, the Grantee, University Acquisition Corp., a Delaware
corporation and a wholly owned subsidiary of the Grantee ("Merger Sub"), and the
Grantor are entering into an Agreement and Plan of Merger,  dated as of the date
hereof (the "Merger  Agreement"),  which provides,  among other things,  for the
merger of Merger Sub with and into Grantor (the "Merger");

                  WHEREAS,  the Grantee and Merger Sub have  requested  that the
Grantor  grant to the Grantee an option to purchase  up to  3,372,255  shares of
Common Stock, par value $0.01 per share, of the Grantor (the "Common Stock"), on
the terms and subject to the conditions hereof; and

                  WHEREAS,  the  Grantor  is willing  to grant the  Grantee  the
requested option.

                  NOW,  THEREFORE,  in  consideration  of the  premises  and the
mutual  covenants and agreements  set forth herein,  the parties hereto agree as
follows:

                  1. The  Option;  Exercise;  Adjustments;  Payment  of  Spread;
Repurchase Right. (a) Contemporaneously herewith the Grantee, Merger Sub and the
Grantor are entering into the Merger  Agreement.  Subject to the other terms and
conditions  set forth  herein,  the  Grantor  hereby  grants to the  Grantee  an
irrevocable  option (the "Option") to purchase up to 3,372,255  shares of Common
Stock (the  "Shares")  at a cash  purchase  price equal to $31.00 per share (the
"Purchase  Price").  The Option may be exercised by the Grantee,  in whole or in
part,  at any  time,  or from  time to time,  following  (but not  prior to) the
occurrence of the events set forth in any of clauses (i), (ii), (iii) or (iv) of
Section 2(d) hereof, and prior to the Termination Date (as defined herein).

                  (b) In the event the Grantee  wishes to  exercise  the Option,
the  Grantee  shall send a written  notice to the Grantor  (the "Stock  Exercise
Notice")  specifying the total number of Shares it wishes to purchase and a date
(subject




<PAGE>

to the expiration or termination of any applicable  waiting period under the HSR
Act (as defined  below)) not later than 10  business  days and not earlier  than
three  business days  following the date such notice is given for the closing of
such  purchase.  In the  event  of  any  change  in the  number  of  issued  and
outstanding  shares of  capital  stock of the  Company  (by  reason of any stock
dividend, stock split, split-up,  recapitalization,  merger, issuance of capital
stock upon  exercise of warrants or options or any other  event),  the number of
Shares  subject  to this  Option  and the  purchase  price  per  Share  shall be
appropriately adjusted to restore the Grantee to its rights hereunder, including
its right to purchase  Shares  representing  19.9% of the  capital  stock of the
Grantor  entitled to vote  generally  for the  election of the  directors of the
Grantor which is issued and outstanding immediately prior to the exercise of the
Option.

                  (c) If at any time the Option is then exercisable  pursuant to
the terms of Section  1(a)  hereof and at or prior to such time the  termination
fee  referred  to in Section  8.5(b) of the Merger  Agreement  shall have become
payable,  the  Grantee may from time to time elect,  in lieu of  exercising  the
Option to purchase  Shares  provided in Section 1(a)  hereof,  to send a written
notice to the Grantor (a "Cash  Exercise  Notice")  specifying  a date not later
than 20 business days and not earlier than 10 business  days  following the date
such  notice is given on which  date the  Grantor  shall pay to the  Grantee  an
amount in cash (the  "Cancellation  Amount") equal to the Spread (as hereinafter
defined)  multiplied by all or such portion of the Shares  subject to the Option
as Grantee shall specify. As used herein "Spread" shall mean the excess, if any,
over the Purchase  Price of the higher of (x) if  applicable,  the highest price
per share of Common Stock (including any brokerage  commissions,  transfer taxes
and soliciting dealers' fees) paid or proposed to be paid by any person pursuant
to any Acquisition Proposal (as defined in the Merger Agreement) occurring after
the date of this Agreement and prior to the Termination  Date (the  "Alternative
Purchase  Price") or (y) the average of the closing bid and asked  prices of the
Common Stock on the Nasdaq National Market  ("Nasdaq") or on such other national
securities on which the shares of the Grantor's  common stock are then listed on
the last trading day  immediately  prior to the date of the Cash Exercise Notice
(the "Closing Price").  If the Alternative  Purchase Price includes any property
other than cash,  the  Alternative  Purchase  Price  shall be the sum of (i) the
fixed cash


                                       -2-

<PAGE>

amount,  if any,  included in the Alternative  Purchase Price plus (ii) the fair
market  value  of such  other  property.  If such  other  property  consists  of
securities with an existing  public trading  market,  the average of the closing
prices (or the average of the closing bid and asked prices if closing prices are
unavailable) for such securities in their principal public trading market on the
five trading days ending five days prior to the date of the Cash Exercise Notice
shall be deemed to equal the fair market value of such  property.  If such other
property  consists of something  other than cash or securities  with an existing
public trading  market and, as of the payment date for the Spread,  agreement on
the value of such other property has not been reached,  the Alternative Purchase
Price shall be deemed to equal the Closing Price.  Upon exercise of its right to
receive cash pursuant to this Section 1(c),  the  obligations  of the Grantor to
deliver  Shares  pursuant to Section 3 shall be terminated  with respect to such
number of Shares for which the Grantee shall have elected to be paid the Spread.

                  (d) At the  request  of the  Grantor  at any time  during  the
180-day  period  commencing  on each date on which the Option is exercised  (the
"Call  Period"),  the Grantor may repurchase  from the Grantee,  and the Grantee
shall sell to the  Grantor,  any or all of the Shares  acquired  by the  Grantee
pursuant  hereto  as a result of such  exercise  and with  respect  to which the
Grantee has beneficial  ownership at the time of such  repurchase at a price per
share equal to the Repurchase  Price (defined below) per share in respect of the
Shares so acquired  (such price per share  multiplied by the number of Shares to
be repurchased pursuant to this Section 1(d) being herein called the "Repurchase
Consideration").  Each date on which the Grantor exercises its rights under this
Section  1(d) by  delivering  its  request to the  Grantee is  referred  to as a
"Grantor Request Date." "Repurchase Price" per share shall be the greater of (i)
the Purchase  Price,  and (ii) the average  (rounded to the nearest  cent, or if
there  shall not be a nearest  cent,  to the next  highest  cent) of the  volume
weighted  averages  (rounded  to the  nearest  cent,  or if there shall not be a
nearest  cent,  to the next highest cent) of the closing ask prices of one share
of Common  Stock on Nasdaq as reported by Bloomberg  Financial  Markets (or such
other  source as the parties  shall  agree in  writing)  for each of the Trading
Days.  "Trading  Days" means the Nasdaq  trading days during the Call Period and
prior to the  applicable  Grantor  Request  Date.  If the Grantor  exercises its
rights under this Section 1(d), the


                                       -3-

<PAGE>
Grantor shall,  within five business days after the applicable  Grantor  Request
Date,  pay the applicable  Repurchase  Consideration  in  immediately  available
funds,  and the Grantee shall surrender to the Grantor  certificates  evidencing
the Shares  purchased  hereunder,  and the Grantee  shall warrant to the Grantor
that, immediately prior to the repurchase thereof pursuant to this Section 1(d),
the  Grantee had sole record and  beneficial  ownership  of such Shares and that
such Shares were then held free and clear of all encumbrances.

                  2. Conditions to Delivery of Shares. The Grantor's  obligation
to deliver  Shares upon exercise of the Option is subject only to the conditions
that:

                  (a) No  preliminary  or  permanent  injunction  or other order
         issued  by  any  federal  or  state  court  of  competent  jurisdiction
         prohibiting the delivery of the Shares shall be in effect; and

                  (b) Any applicable waiting periods under the Hart-Scott-Rodino
         Antitrust  Improvements  Act of 1976 (the "HSR Act") shall have expired
         or been terminated; and

                  (c) the  representations and warranties of the Grantee made in
         Section 5 of this  Agreement  shall be true and correct in all material
         respects as of the date of the  closing of the  issuance of the Shares;
         and

                  (d) (i) in the event that (A) a bona fide Acquisition Proposal
         (as  defined  in the  Merger  Agreement)  shall  have  been made to the
         Company or any of its  subsidiaries  or any of its  stockholders or any
         person or entity  shall have  announced  an  intention  (whether or not
         conditional)  to make  an  Acquisition  Proposal  with  respect  to the
         Company or any of its subsidiaries, and on or following the date of the
         Merger Agreement but prior to the date of the Stockholders  Meeting (as
         defined   in  the  Merger   Agreement)   such   Acquisition   Proposal,
         announcement or intention is or becomes  publicly known,  and (B) on or
         following  the date of the Merger  Agreement but prior to the time such
         Acquisition Proposal,  announcement or intention is or becomes publicly
         known, the occurrence of a


                                       -4-

<PAGE>

         Parent  Material  Adverse  Effect (as defined in the Merger  Agreement)
         shall not have become publicly known,  and (C) on or following the date
         on which such  Acquisition  Proposal,  announcement  or intention is or
         becomes  publicly known,  the Merger  Agreement is terminated by either
         the  Grantee or the Grantor  pursuant to Section  8.2(ii) of the Merger
         Agreement,  or (ii) the Merger  Agreement is  terminated by the Grantor
         pursuant  to  Section  8.3(a)  of the  Merger  Agreement;  or (iii) the
         Merger  Agreement  is  terminated  by the  Grantee  pursuant to Section
         8.4(a)  of the  Merger  Agreement;  or  (iv)  the  Grantor  shall  have
         delivered  to Grantee  the  written  notification  pursuant  to Section
         8.3(a)(ii) of the Merger  Agreement and the Grantee shall have notified
         the Grantor in writing  that the  Grantee  does not intend to match the
         Superior Proposal (as defined in the Merger  Agreement)  referred to in
         such notification.  As used in this Agreement,  "person" shall have the
         meaning specified in Sections 3(a)(9) and 13(d)(3) of the Exchange Act.

                  3. The Closing.  (a) Any closing hereunder shall take place on
the date specified by the Grantee in its Stock Exercise  Notice or Cash Exercise
Notice or as specified in Section 1(d), as the case may be, at 10:00 A.M., local
time,  at the offices of Sullivan & Cromwell,  125 Broad Street,  New York,  New
York,  or, if the conditions set forth in Section 2(a), (b) or (c) have not then
been satisfied,  on the second  business day following the  satisfaction of such
conditions, or at such other time and place as the parties hereto may agree (the
"Closing Date").  On the Closing Date, (i) in the event of a closing pursuant to
Section 1(b) hereof,  the Grantor will deliver to the Grantee a  certificate  or
certificates,  representing  the Shares in the  denominations  designated by the
Grantee in its Stock  Exercise  Notice and the Grantee will purchase such Shares
from the Grantor at the price per Share equal to the Purchase Price, (ii) in the
event of a closing pursuant to Section 1(c) hereof,  the Grantor will deliver to
the Grantee cash in an amount  determined  pursuant to Section  1(c) hereof;  or
(iii) in the event of a closing  pursuant to Section  1(d)  hereof,  the Grantor
will  deliver to the Grantee  cash in an amount  determined  pursuant to Section
1(d) hereof.  Any payment made by the Grantee to the Grantor,  or by the Grantor
to the Grantee, pursuant to this Agreement shall be made by


                                       -5-

<PAGE>

certified or official  bank check or by wire transfer of federal funds to a bank
designated by the party receiving such funds.

                  (b) The Grantee agrees not to transfer or otherwise dispose of
the Option or the Shares, or any interest therein, except in compliance with the
Securities  Act of 1933, as amended (the  "Securities  Act") and any  applicable
state   securities  law.  The  Grantee  further  agrees  that  the  certificates
representing  the Shares shall bear an appropriate  legend  relating to the fact
that such Shares have not been registered under the Securities Act.

                  4.  Representations and Warranties of the Grantor. The Grantor
represents  and  warrants to the Grantee  that (a) the Grantor is a  corporation
duly  organized,  validly  existing and in good  standing  under the laws of the
State of Delaware and has the requisite  corporate  power and authority to enter
into  and  perform  this  Agreement;  (b) the  execution  and  delivery  of this
Agreement  by  the  Grantor  and  the  consummation  by it of  the  transactions
contemplated  hereby have been duly  authorized by the Board of Directors of the
Grantor  and this  Agreement  has been duly  executed  and  delivered  by a duly
authorized officer of the Grantor and constitutes a valid and binding obligation
of the Grantor, enforceable in accordance with its terms, subject to bankruptcy,
insolvency, fraudulent transfer, reorganization,  moratorium and similar laws of
general applicability  relating to or affecting creditors' rights and to general
equity principles;  (c) the Grantor has taken all necessary  corporate action to
authorize  and reserve the Shares  issuable  upon exercise of the Option and the
Shares, when issued and delivered by the Grantor upon exercise of the Option and
paid for by the Grantee as contemplated hereby, will be duly authorized, validly
issued,  fully paid and non-assessable and free of preemptive rights; (d) except
as otherwise required by the HSR Act or the rules and regulations of Nasdaq, the
execution and delivery of this Agreement by the Grantor and the  consummation by
it of the transactions  contemplated hereby do not require the consent,  waiver,
approval or  authorization  of or any filing with any person or public authority
and  will  not  violate,  result  in a  breach  of or  the  acceleration  of any
obligation  under, or constitute a default under, any provision of the Grantor's
certificate of incorporation or bylaws, or any indenture, mortgage, lien, lease,
agreement, contract,  instrument, order, rule, regulation,  judgment, ordinance,
or decree, or


                                       -6-

<PAGE>

restriction  by which the  Grantor  or any of its  subsidiaries  or any of their
respective  properties or assets is bound;  (e) no "fair  price",  "moratorium",
"control  share  acquisition,"   "interested   shareholder"  or  other  form  of
antitakeover statute or regulation  (including but not limited to Section 203 of
the  Delaware  General  Corporation  Law)  is or  shall  be  applicable  to  the
acquisition of Shares pursuant to this Agreement;  and (f) the Grantor has taken
all  corporate  action  necessary so that any Shares  acquired  pursuant to this
Agreement  shall not be counted for purposes of determining the number of shares
of Common Stock  beneficially  owned by the Grantee or any of its  Affiliates or
Associates pursuant to the Rights Agreement (as defined in the Merger Agreement,
the terms "Affiliate" and "Associate" having the respective meanings ascribed to
them in the Rights Agreement).

                  5.  Representations and Warranties of the Grantee. The Grantee
represents  and  warrants to the Grantor  that (a) the Grantee is a  corporation
duly  organized,  validly  existing and in good  standing  under the laws of the
State of Delaware and has the requisite  corporate  power and authority to enter
into  and  perform  this  Agreement,  (b) the  execution  and  delivery  of this
Agreement  by  the  Grantee  and  the  consummation  by it of  the  transactions
contemplated  hereby have been duly authorized by all necessary corporate action
on the  part of the  Grantee  and this  Agreement  has been  duly  executed  and
delivered by a duly  authorized  officer of the Grantee and  constitutes a valid
and binding obligation of the Grantee, enforceable in accordance with its terms,
subject  to  bankruptcy,   insolvency,   fraudulent  transfer,   reorganization,
moratorium  and similar laws of general  applicability  relating to or affecting
creditors'  rights  and to general  equity  principles;  and (c) the  Grantee is
acquiring the Option and, if and when it exercises the Option, will be acquiring
the Shares issuable upon the exercise thereof for its own account and not with a
view to  distribution or resale in any manner which would be in violation of the
Securities Act.

                  6. Listing of Shares; Filings;  Governmental Consents. Subject
to applicable law and the rules and regulations of Nasdaq or such other national
securities  exchange on which the shares of the Grantor's  common stock are then
listed,  after the  Option  becomes  exercisable  hereunder,  the  Grantor  will
promptly  file an  application  to list the  Shares on  Nasdaq or on such  other
national securi-

                                      -7-
<PAGE>

ties exchange on which the shares of the Grantor's  common stock are then listed
and will use its reasonable  best efforts to obtain approval of such listing and
to effect all  necessary  filings by the  Grantor  under the HSR Act;  provided,
however,  that if the Grantor is unable to effect such  listing on Nasdaq by the
Closing Date, the Grantor will  nevertheless  be obligated to deliver the Shares
upon the Closing Date.  Each of the parties hereto will use its reasonable  best
efforts to obtain consents of all third parties and governmental authorities, if
any,  necessary to the  consummation  of the  transactions  contemplated by this
Agreement.

                  7.  Registration  Rights.  (a) In the event  that the  Grantee
shall  desire to sell any of the Shares  within two years after the  purchase of
such Shares pursuant to this Agreement,  and such sale requires,  in the opinion
of counsel to the Grantee, which opinion shall be reasonably satisfactory to the
Grantor and its counsel,  registration  of such Shares under the Securities Act,
the  Grantor  will  cooperate  with  the  Grantee  and any  underwriters  (which
underwriters must be reasonably satisfactory to the Grantor) in registering such
Shares for resale, including, without limitation, promptly filing a registration
statement which complies with the  requirements of applicable  federal and state
securities  laws,  and  entering  into  an  underwriting   agreement  with  such
underwriters  upon such terms and  conditions  as are  customarily  contained in
underwriting agreements with respect to secondary  distributions;  provided that
the  Grantor  shall not be  required to have  declared  effective  more than two
registration  statements  hereunder and shall be entitled to delay the filing or
effectiveness  of any  registration  statement  and may  suspend  the use of any
registration  statement (and related prospectus) for one or more periods of time
not  exceeding  an  aggregate  of 60 days in any one year period if the offering
would,  in the  judgment  of the  board of  directors  of the  Grantor,  require
premature   disclosure  of  any  material  corporate   development  or  material
transaction  involving  the Grantor or  interfere  with any  previously  planned
securities offering by the Grantor.  In addition,  upon receipt of notice of the
happening  of any  event  as a  result  of  which  any  registration  statement,
prospectus or prospectus supplement,  contains any untrue statements of material
fact or fails or omits to state any material fact required to be stated  therein
or necessary to make the statements therein, in light of the circumstances under
which they are made, not misleading the Grantee shall


                                       -8-

<PAGE>

forthwith  discontinue  the  disposition  of any Shares under such  registration
statement,  prospectus or prospectus  supplement until the Grantee receives from
the Grantor  copies (which  subject to the  limitations  on suspension set forth
above  shall  promptly  be made  available  by the  Grantor)  of an  amended  or
supplemented  registration  statement,  prospectus  or  supplement  so that,  as
thereafter delivered to purchasers of such Shares, such registration  statement,
prospectus or prospectus  supplement  shall not contain any untrue  statement of
material  fact or fail or omit to state any material  fact required to be stated
therein  or  necessary  to  make  the  statements   therein,  in  light  of  the
circumstances under which they are made, not misleading.

                  (b)  If  the  Common  Stock  is  registered  pursuant  to  the
provisions  of this Section 7, the Grantor  agrees (i) to furnish  copies of the
registration statement and the prospectus relating to the Shares covered thereby
in such numbers as the Grantee may from time to time reasonably request and (ii)
if any event shall occur as a result of which it becomes  necessary  to amend or
supplement any registration  statement or prospectus,  to prepare and file under
the  applicable  securities  laws  such  amendments  and  supplements  as may be
necessary  to keep  available  for at least 45 days a  prospectus  covering  the
Shares  meeting the  requirements  of such  securities  laws, and to furnish the
Grantee such numbers of copies of the  registration  statement and prospectus as
amended or supplemented  as may reasonably be requested.  The Grantor shall bear
the cost of the  registration,  including,  but not limited to, all registration
and filing fees,  printing  expenses,  and fees and disbursements of counsel and
accountants  for the  Grantor,  except that the  Grantee  shall pay the fees and
disbursements of its counsel,  and the underwriting fees and selling commissions
applicable to the shares of Common Stock sold by the Grantee.  The Grantor shall
indemnify and hold harmless (i) the Grantee, its affiliates and its officers and
directors and (ii) each underwriter and each person who controls any underwriter
within the meaning of the Securities Act or the Securities Exchange Act of 1934,
as amended (collectively, the "Underwriters") ((i) and (ii) being referred to as
"Indemnified  Parties")  against any losses,  claims,  damages,  liabilities  or
expenses,  to which the Indemnified Parties may become subject,  insofar as such
losses,  claims,  damages,  liabilities  (or  actions  in respect  thereof)  and
expenses  arise out of or are based upon any untrue  statement or alleged untrue
statement of any material


                                       -9-


<PAGE>

fact contained or incorporated by reference in any registration  statement filed
pursuant to this  paragraph,  or arise out of or are based upon the  omission or
alleged  omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading;  provided,  however,
that the Grantor will not be liable in any such case to the extent that any such
loss, liability,  claim, damage or expense arises out of or is based upon (A) an
untrue  statement or alleged untrue statement in or omission or alleged omission
from  any  such  documents  in  reliance  upon and in  conformity  with  written
information  furnished to the Grantor by the Indemnified  Parties  expressly for
use or  incorporation  by  reference  therein,  or (B) the fact that the  person
asserting any such loss,  liability,  claim, damage or expense did not receive a
copy of an amended preliminary  prospectus or the final prospectus (or the final
prospectus as amended or supplemented)  at or prior to the written  confirmation
of the sale of the Shares to such  person  because of the failure of the Grantee
to so provide such amended preliminary or final prospectus.

                  (c) The Grantee and the Underwriters  shall indemnify and hold
harmless the Grantor,  its affiliates and its officers and directors against any
losses,  claims,  damages,  liabilities  or expenses to which the  Grantor,  its
affiliates  and its officers and directors may become  subject,  insofar as such
losses,  claims,  damages,  liabilities  (or  actions  in respect  thereof)  and
expenses arise out of or are based upon (i) any untrue statement of any material
fact contained or incorporated by reference in any registration  statement filed
pursuant to this  paragraph,  or arise out of or are based upon the  omission or
alleged  omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading,  in each case to the
extent,  but only to the extent,  that such untrue  statement or alleged  untrue
statement  or omission  or alleged  omission  was made in  reliance  upon and in
conformity with written  information  furnished to the Grantor by the Grantee or
the  Underwriters,  as  applicable,  specifically  for use or  incorporation  by
reference  therein,  or (ii) the fact that the person  asserting  any such loss,
liability,  claim,  damage  or  expense  did not  receive  a copy of an  amended
preliminary  prospectus  or the final  prospectus  (or the final  prospectus  as
amended or supplemented) at or prior to the written  confirmation of the sale of
the Shares to such person because of the failure of the


                                      -10-

<PAGE>

Grantee to so provide such amended preliminary or final prospectus.

                  (d)  Promptly  after  receipt by an  indemnified  party  under
subsection (b) or (c) above of notice of the  commencement  of any action,  such
indemnified party shall, if a claim in respect thereof is to be made against the
indemnifying  party  under such  subsection,  notify the  indemnifying  party in
writing  of  the  commencement  thereof;  but  the  omission  so to  notify  the
indemnifying  party shall not relieve it from any liability which it may have to
any  indemnified  party otherwise than under such  subsection.  In case any such
action shall be brought  against any  indemnified  party and it shall notify the
indemnifying party of the commencement  thereof, the indemnifying party shall be
entitled to participate  therein and, to the extent that it shall wish,  jointly
with any other  indemnifying  party  similarly  notified,  to assume the defense
thereof,  with counsel  satisfactory to such  indemnified  party (who shall not,
except with the consent of the indemnified party, be counsel to the indemnifying
party),  and, after notice from the indemnifying party to such indemnified party
of its election so to assume the defense thereof,  the indemnifying  party shall
not be liable to such  indemnified  party  under such  subsection  for any legal
expenses  of other  counsel  or any other  expenses,  in each case  subsequently
incurred by such indemnified party, in connection with the defense thereof other
than reasonable costs of  investigation.  No indemnified  party shall settle any
action or claim  without the consent of the  indemnifying  party,  which consent
shall not be unreasonably withheld or delayed.

                  8.  Expenses.  Each party  hereto  shall pay its own  expenses
incurred in connection  with this  Agreement,  except as otherwise  specifically
provided herein.

                  9.  Modification  or Amendment.  Subject to the  provisions of
applicable  law,  the  parties  hereto may modify or amend  this  Agreement,  by
written  agreement  executed and  delivered by duly  authorized  officers of the
respective parties.

                  10. Counterparts. This Agreement may be executed in any number
of  counterparts,   each  such  counterpart  being  deemed  to  be  an  original
instrument,  and all  such  counterparts  shall  together  constitute  the  same
agreement.



                                      -11-

<PAGE>

                  11.  GOVERNING LAW AND VENUE;  WAIVER OF JURY TRIAL.  (a) THIS
AGREEMENT  SHALL  BE  DEEMED  TO BE  MADE  IN  AND  IN  ALL  RESPECTS  SHALL  BE
INTERPRETED,  CONSTRUED AND GOVERNED BY AND IN  ACCORDANCE  WITH THE LAWS OF THE
STATE OF NEW YORK WITHOUT REGARD TO THE CONFLICT OF LAW PRINCIPLES THEREOF.  The
parties hereby irrevocably submit to the jurisdiction of the courts of the State
of New York and the Federal  courts of the United  States of America  located in
the  Borough  of  Manhattan,  The  City of New York  solely  in  respect  of the
interpretation  and enforcement of the provisions of this Agreement,  the Merger
Agreement  and of the other  documents  referred  to in this  Agreement  and the
Merger  Agreement,  and in respect of the transactions  contemplated  hereby and
thereby,  and hereby waive, and agree not to assert, as a defense in any action,
suit or proceeding for the  interpretation or enforcement  hereof or of any such
document, that it is not subject thereto or that such action, suit or proceeding
may not be  brought  or is not  maintainable  in said  courts  or that the venue
thereof may not be appropriate or that this Agreement,  the Merger Agreement, or
any such  document  may not be  enforced in or by such  courts,  and the parties
hereto  irrevocably  agree  that all  claims  with  respect  to such  action  or
proceeding  shall be heard and  determined  in such a New York  State or Federal
court. The parties hereby consent to and grant any such court  jurisdiction over
the person of such parties and over the subject matter of such dispute and agree
that  mailing of process or other papers in  connection  with any such action or
proceeding  in the manner  provided in Section 12 or in such other manner as may
be permitted by law, shall be valid and sufficient service thereof.

                  (b) EACH PARTY  ACKNOWLEDGES  AND AGREES THAT ANY  CONTROVERSY
WHICH MAY ARISE UNDER THIS AGREEMENT,  THE COMPOUND AGREEMENT,  THE STOCK OPTION
AGREEMENT OR THE VOTING AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT
ISSUES,  AND THEREFORE EACH SUCH PARTY HEREBY  IRREVOCABLY  AND  UNCONDITIONALLY
WAIVES  ANY  RIGHT  SUCH  PARTY  MAY HAVE TO A TRIAL BY JURY IN  RESPECT  OF ANY
LITIGATION  DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AGREEMENT,
THE MERGER AGREEMENT,  THE OTHER DOCUMENTS REFERRED TO IN THIS AGREEMENT AND THE
MERGER AGREEMENT, OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY. EACH PARTY
CERTIFIES AND ACKNOWLEDGES THAT (I) NO REPRESENTATIVE,  AGENT OR ATTORNEY OF ANY
OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD
NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER, (II) EACH
SUCH PARTY


                                      -12-

<PAGE>

UNDERSTANDS AND HAS CONSIDERED THE IMPLICATIONS OF THIS WAIVER,  (III) EACH SUCH
PARTY MAKES THIS WAIVER  VOLUNTARILY,  AND (IV) EACH SUCH PARTY HAS BEEN INDUCED
TO ENTER INTO THIS  AGREEMENT  BY, AMONG OTHER  THINGS,  THE MUTUAL  WAIVERS AND
CERTIFICATIONS IN THIS SECTION 11.

                  12.  Notices.  Any  notice,  request,   instruction  or  other
document to be given  hereunder  by any party to the others  shall be in writing
and  delivered  personally  or sent by  registered  or certified  mail,  postage
prepaid, or by facsimile:

                  if to the Grantee:

                           Richard T. Collier
                           Pharmacia & Upjohn, Inc.
                           95 Corporate Drive
                           Bridgewater, NJ  08807
                           fax:  (908) 306-4489

                  with copies to:

                           Neil T. Anderson
                           Matthew G. Hurd
                           Morgan N. Neuwirth
                           Martin J. Travers
                           Sullivan & Cromwell
                           125 Broad Street
                           New York, NY 10004
                           fax:  (212) 558-3588

                  if to the Grantor:

                           Bruce E. MacMillan
                           SUGEN, Inc.
                           230 East Grand Avenue
                           South San Francisco, CA  94080
                           fax:  (650) 553-8342



                                      -13-

<PAGE>

                  with  copies to:

                           Alan C. Mendelson
                           Suzanne Sawochka Hooper
                           Gianna M. Bosko
                           Cooley Godward LLP
                           5 Palo Alto Square
                           3000 El Camino Real
                           Palo Alto, California 94306
                           fax:  (650) 857-0663

or to such other  persons or  addresses as may be  designated  in writing by the
party to receive such notice as provided above.

                  13. Entire Agreement.  This Agreement  (including any exhibits
and schedules hereto),  the Merger Agreement and the other documents referred to
in this Agreement and the Merger Agreement, constitute the entire agreement, and
supersede  all  other  prior  agreements,  understandings,  representations  and
warranties both written and oral, among the parties, with respect to the subject
matter hereof.

                  14.  No  Third  Party  Beneficiaries.  This  Agreement  is not
intended to confer upon any person or entity  other than the parties  hereto any
rights or remedies hereunder.

                  15.  Severability.  The provisions of this Agreement  shall be
deemed severable and the invalidity or  unenforceability  of any provision shall
not affect the validity or enforceability of the other provisions hereof. If any
provision of this Agreement,  or the application thereof to any person or entity
or any circumstance,  is invalid or unenforceable,  (a) a suitable and equitable
provision shall be substituted  therefor in order to carry out, so far as may be
valid and  enforceable,  the intent and purpose of such invalid or unenforceable
provision and (b) the remainder of this  Agreement and the  application  of such
provision to other persons or entities or circumstances shall not be affected by
such   invalidity   or   unenforceability,   nor  shall   such   invalidity   or
unenforceability affect the validity or enforceability of such provision, or the
application thereof, in any other jurisdiction.

                  16. Specific Performance.  The parties hereto each acknowledge
that, in view of the uniqueness of the subject matter hereof, the parties hereto
would not have an


                                      -14-

<PAGE>

adequate remedy at law for money damages if this Agreement were not performed in
accordance with its terms,  and therefore agree that the parties hereto shall be
entitled to specific  enforcement  of the terms  hereof in addition to any other
remedy to which the parties hereto may be entitled at law or in equity.

                  17.  Assignment.  This  Agreement  shall not be  assignable by
operation of law or otherwise;  provided,  however,  that the Grantee may assign
its rights and obligations under this Agreement to any of its direct or indirect
wholly owned subsidiaries  (including Merger Sub). Any purported assignment made
in contravention of this Agreement shall be null and void.

                  18. Captions.  The Section captions herein are for convenience
of reference only and do not constitute  part of this Agreement and shall not be
deemed to limit or otherwise affect any of the provisions hereof.

                  19. Termination.  (a) The right to exercise the Option granted
pursuant to this Agreement shall terminate at (and the Option shall no longer be
exercisable  after) the  earliest of (i) the  Effective  Time (as defined in the
Merger  Agreement),  (ii) the first  anniversary of the earliest to occur of the
events set forth in any of clauses (i), (ii), (iii) or (iv) of Section 2(d), and
(iii) the fifteenth day following  the  termination  of the Merger  Agreement if
prior to such  fifteenth  day the events set forth in any of clauses (i),  (ii),
(iii) or (iv) of Section 2(d) shall not have occurred  (such earliest date being
referred to in this Agreement as the "Termination Date");  provided that, if the
Option cannot be exercised or the Shares cannot be delivered to the Grantee upon
such exercise because one or more of the conditions set forth in Section 2(a) or
(b) hereof have not yet been satisfied,  the Termination  Date shall be extended
until  thirty  days after such  impediment  to  exercise  or  delivery  has been
removed.

                  (b)  All  representations  and  warranties  contained  in this
Agreement shall survive delivery of and payment for the Shares.

                  20. Profit Limitation.  Notwithstanding any other provision of
this Agreement or the Merger Agreement, any Cancellation Amount shall be reduced
(but not below zero) to the extent  necessary  so that the sum of the portion of
any


                                      -15-
<PAGE>

termination  fee described in Section  8.5(b) of the Merger  Agreement  actually
paid to the Grantee (such portion  actually paid, the  "Termination  Fee"),  the
aggregate of all Cancellation Amounts paid to Grantee pursuant to this Agreement
and the cash proceeds  actually received by the Grantee as the result of selling
Shares  to a  third  party  which  acquires  more  than  50%  of  the  Grantor's
outstanding  voting securities (other than the Company or any of its affiliates)
shall not exceed  $21,900,000.  In no event  shall (i) the sum of the  aggregate
Cancellation  Amounts paid to Grantee  pursuant to this  Agreement  and the cash
proceeds  actually  received by the Grantee as the result of selling Shares to a
third party which  acquires  more than 50% of the Grantor's  outstanding  voting
securities (other than the Company or any of its affiliates) exceed $21,900,000,
or (ii) the sum of the Termination Fee, the aggregate  Cancellation Amounts paid
to Grantee pursuant to this Agreement and the cash proceeds actually received by
the Grantee as the result of selling Shares to a third party which acquires more
than 50% of the Grantor's  outstanding voting securities (other than the Company
or any of its affiliates) exceed $21,900,000.


                                      -16-

<PAGE>


                  IN WITNESS WHEREOF,  this Agreement has been duly executed and
delivered  by duly  authorized  officers  of the  parties  hereto as of the date
hereof.


                                      SUGEN, INC.



                                      By: /s/ Stephen Evans-Freke
                                          ---------------------------------
                                          Name:   Stephen Evans-Freke
                                          Title:  Chairman of the Board and
                                                    Chief Executive Officer


                                      PHARMACIA & UPJOHN, INC.



                                      By: /s/ Christopher J. Coughlin
                                          ---------------------------------
                                          Name:   Christopher J. Coughlin
                                          Title:  Executive Vice President


                                      UNIVERSITY ACQUISITION CORP.



                                      By: /s/ Mats Petterson
                                          ---------------------------------
                                          Name:   Mats Petterson
                                          Title:  Senior Vice President


                                      -17-




                                                                    EXHIBIT 99.1

Pharmacia & Upjohn to Acquire SUGEN, Inc.
Strategic Acquisition Strengthens Drug Discovery Capabilities and
Oncology Portfolio

BRIDGEWATER,  N.J. and  SOUTH SAN  FRANCISCO,  Calif.--(BWHealthWire) --June 15,
1999--Pharmacia & Upjohn, Inc. (NYSE: PNU - news) and SUGEN (NASDAQ:SUGN - news)
today  announced the signing of an agreement under which Pharmacia & Upjohn will
acquire  complete  ownership of SUGEN,  a  biotechnology  company and  worldwide
leader   in   target-driven   drug   discovery   and   development   for   novel
development-stage cancer therapies.

Under the terms of the agreement which is valued at  approximately  $650 million
on a net basis, each of approximately 23.5 million shares of SUGEN stock will be
exchanged for  approximately  $31 worth of Pharmacia & Upjohn stock,  so long as
the price of Pharmacia & Upjohn stock is between  $60.16 and $49.22 at the close
of the transaction.  In no event will SUGEN stockholders  receive less than .515
share of Pharmacia & Upjohn common stock,  nor more than .630 share of Pharmacia
& Upjohn stock for each share of SUGEN common stock.  The exact  exchange  ratio
will be based on the average price of Pharmacia & Upjohn stock prior to closing.
The transaction will be accounted for as a pooling of interests and will qualify
as a tax-free exchange.  The transaction has received the approval of the Boards
of Directors of both Pharmacia & Upjohn and SUGEN and is subject to the approval
by SUGEN's stockholders and other customary regulatory approvals.  Under certain
circumstances, if the merger agreement is terminated, Pharmacia & Upjohn has the
right to purchase up to 19.9% of SUGEN's common stock and has the right to a fee
of $17 million.

"SUGEN's  target-driven  approach to drug discovery and development is supported
by an  outstanding  scientific  team  and  proprietary  technology  that  we can
leverage  across our  company's  core research  areas," said Fred Hassan,  Chief
Executive   Officer,   Pharmacia  &  Upjohn.   "In  addition  to  enhancing  our
genomics-based  drug discovery  capabilities,  this acquisition  strengthens our
oncology  portfolio  by  providing  us with new  therapeutic  approaches  to the
treatment  of cancer.  We are  already in  cytotoxics,  hormonals  and  adjuvant
therapies. With the addition of the cytostatic platform represented by SUGEN, we
position P&U to become the new challenger in the oncology category."

Hassan added:  "The acquisition of SUGEN is yet another example of the new P&U's
strategy to supplement our internal R&D initiatives with external innovation."

Stephen Evans-Freke,  Chairman and Chief Executive Officer of SUGEN, said, "This
agreement  with Pharmacia & Upjohn  provides SUGEN with the resources,  critical
mass and global  infrastructure  to commercialize  the cancer drug candidates in
our pipeline  far more  rapidly  than we could  achieve on our own. It will also
enable us to apply our unique  capabilities to other important  disease areas in
which our efforts to date have been severely resource constrained."

The key to  SUGEN's  approach  to drug  discovery  is its broad and  proprietary
expertise  in  identifying   cell   signaling   targets  known  as  kinases  and
phosphatases.  These molecules are needed for normal  signaling to occur between
and within cells. Abnormal signaling can affect cell growth and division and can
result  in cancer  and  other  diseases.  SUGEN is a leader  in  developing  new
therapeutic  approaches  to these  diseases  through  its  development  of small
molecule inhibitors that regulate particular signaling pathways.

<PAGE>

SUGEN currently has three  anti-cancer drugs in clinical  development  including
novel cytostatic agents and angiogenesis inhibitors.  In addition to its current
focus in  oncology,  SUGEN is applying its  technology  platform to identify and
validate novel targets for a range of potential clinical applications.

"SUGEN's  outstanding  team of  scientists  has built a  substantial  technology
platform   including   an   impressive    intellectual    property    portfolio,
state-of-the-art genomics and bioinformatics, a large portfolio of novel targets
and  novel  chemistries  and a  growing  pipeline  of  candidates  that will add
immediate value to our research and development program," said Goran Ando, M.D.,
Pharmacia  &  Upjohn  Executive  Vice  President  and  President,  Research  and
Development. "Our respective research organizations have complementary strengths
that provide us with an  opportunity  to achieve  significant  synergies  and to
build competitive advantage."

SUGEN will remain  based at its  current  headquarters  in South San  Francisco.
Peter  Hirth,   SUGEN's  current  Executive  Vice  President  and  Chairman  R&D
Committee,  will become  President  of SUGEN and will  report to Ando.  A merger
integration team consisting of senior management  representatives of Pharmacia &
Upjohn and SUGEN has been  appointed to oversee the  successful  integration  of
SUGEN with Pharmacia & Upjohn.

The company  estimates that the transaction  will have a 1-2% dilutive impact on
earnings-per-share  next year and is  expected  to be neutral in an 18-24  month
period.  Said  Hassan,  "The SUGEN  acquisition  is an important  investment  in
sustaining  P&U's  long-term  growth.  Our  previously-stated   goal  of  annual
double-digit earnings growth remains unchanged."

Pharmacia & Upjohn is a global,  innovation-driven pharmaceutical and healthcare
company.  Pharmacia & Upjohn's products,  services and employees demonstrate its
commitment  to  improving  wellness  and  quality of life for people  around the
world.



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