SUGEN INC
10-Q, 1996-11-14
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
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================================================================================

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

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

                                    FORM 10-Q
(Mark one)

   X     Quarterly  report  pursuant  to Section  13 or 15(d) of the  Securities
_______  Exchange Act of 1934.  For the  quarterly  period ended  September  30,
         1996.
         or
         Transition  report  pursuant  to Section 13 or 15(d) of the  Securities
_______  Exchange Act of 1934. For the transition period from ___________ to
         ___________.


                             Commission File Number:
                                     0-24814
                          -----------------------------


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

          Delaware                                          13-3629196
(State or other jurisdiction of                          (I.R.S. Employer
incorporation or organization)                           Identification No.)


               515 Galveston Drive, Redwood City, California 94063
                    (address of principal executive offices)

                                 (415) 306-7700
              (Registrant's telephone number, including area code)


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


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange act of 1934 during
the  preceding 12 months (or for such  shorter  period that the  registrant  was
required to file such reports),  and (2) has been subject to filing requirements
for the past 90 days. Yes  X  No
                          ---    ---

Indicate the number of shares  outstanding  of each of the  issuer's  classes of
common stock, as of the latest  practicable  date.  Common Stock $.01 par value;
12,909,350 shares outstanding at October 31, 1996.


This  report on form 10-Q,  including  all  exhibits,  contains  ___ pages.  The
exhibit index is located on page 14 of this report.

================================================================================

                                       1
<PAGE>


                                   SUGEN, Inc.

                                      INDEX

                                                                       PAGE NO.
                                                                       --------
PART I.   FINANCIAL INFORMATION

Item 1.   Financial Statements and Notes

          Condensed Balance Sheets - September 30, 1996
          and December 31, 1995                                           3

          Statements of Operations - for the three and nine months
          ended September 30, 1996 and 1995                               4

          Condensed Statements of Cash Flows - for the nine
          months ended September 30, 1996 and 1995                        5

          Notes to Financial Statements                                   6

Item 2.   Management's Discussion and Analysis of Financial
          Condition and Results of Operations                             8


PART II.  OTHER INFORMATION


Item 6.   Exhibits and Reports on Form 8-K                                12


Signatures                                                                13


Exhibit Index                                                             14


                                       2
<PAGE>

                          PART I. FINANCIAL INFORMATION

Item 1. FINANCIAL STATEMENTS AND NOTES

                                   SUGEN, Inc.

                            CONDENSED BALANCE SHEETS
                                 (In thousands)


                                                    September 30,   December 31,
                                                        1996            1995
                                                    ------------    ------------
ASSETS                                              (unaudited)
Current assets:                                                     
     Cash and cash equivalents                        $  4,249         $  8,226
     Short-term investments                             29,127           45,027
     Prepaid expenses and other current assets             840            1,034
                                                      --------         --------
        Total current assets                            34,216           54,287
                                                                    
Property and equipment, net                              4,064            4,513
Other assets                                             1,371              443
                                                      --------         --------
                                                      $ 39,651         $ 59,243
                                                      ========         ========
                                                                    
LIABILITIES AND STOCKHOLDERS' EQUITY                                
Current liabilities:                                                
     Accounts payable                                 $  1,052         $    652
     Accrued liabilities                                 5,933            3,587
     Deferred revenue                                     --              6,558
     Capital lease obligations - current portion         1,706            1,354
                                                      --------         --------
        Total current liabilities                        8,691           12,151
                                                                    
Capital lease obligations - non-current portion          3,250            3,651

Commitments                                                         

Stockholders' equity:                                               
                                                                    
     Common stock                                       81,382           81,802
     Deferred compensation                                (785)            (397)
     Note receivable from stockholder                     (883)            --
     Accumulated deficit                               (52,004)         (37,964)
                                                      --------         --------
        Total stockholders' equity                      27,710           43,441
                                                      --------         --------
                                                      $ 39,651         $ 59,243
                                                      ========         ========
                                                                    
  
                             See accompanying notes.
  
                                        3
<PAGE>

<TABLE>

                                              SUGEN, Inc.

                                       STATEMENTS OF OPERATIONS
                               (In thousands, except per share amounts)
                                              (unaudited)
<CAPTION>

                                                           Three Months Ended      Nine Months Ended
                                                             September 30,          September 30,
                                                         ---------------------   --------------------
                                                           1996         1995       1996       1995
                                                         --------    --------    --------    --------
<S>                                                      <C>         <C>         <C>         <C>
Contract revenue (includes amounts from
   related party)                                        $  2,430    $  3,427    $ 10,338    $ 10,302

Costs and expenses:
   Research and development                                 7,047       6,034      21,379      16,597
   General and administrative                               1,104       1,423       4,071       3,812
                                                         --------    --------    --------    --------
   Total costs and expenses                                 8,151       7,457      25,450      20,409
                                                         --------    --------    --------    --------

Operating loss                                             (5,721)     (4,030)    (15,112)    (10,107)

Other income and expenses:
   Interest income                                            450         439       1,738       1,347
   Interest expense                                          (167)       (136)       (521)       (345)
   Gain on sale of investment in Selectide Corporation       --          --          --         1,006
                                                         --------    --------    --------    --------
   Other income, net                                          283         303       1,217       2,008
                                                         --------    --------    --------    --------
Net loss                                                 $ (5,438)   $ (3,727)   $(13,895)   $ (8,099)
                                                         ========    ========    ========    ========

Net loss per share                                       $  (0.51)   $  (0.42)   $  (1.32)   $  (0.93)
                                                         ========    ========    ========    ========

Shares used in computing net loss
  per share                                                10,592       8,780      10,521       8,694
                                                         ========    ========    ========    ========
<FN>
  
                             See accompanying notes.
</FN>

</TABLE>
  
                                        4
<PAGE>
<TABLE>

                                          SUGEN, Inc.

                               CONDENSED STATEMENTS OF CASH FLOWS
                        Increase (decrease) in cash and cash equivalents
                                         (In thousands)
                                          (unaudited)
<CAPTION>
                                                                        Nine Months Ended
                                                                          September 30,
                                                                  ----------------------------
                                                                    1996                1995
                                                                  --------            --------
<S>                                                               <C>                 <C>   
Cash flows from operating activities
Net loss                                                          $(13,895)           $ (8,099)  
Adjustments to reconcile net loss to net cash used in                                
   operating activities:                                                             
   Depreciation and amortization                                     1,673               1,154
   Deferred revenue                                                 (6,558)                (97)
   Issuance of common stock for services                              --                   139
   Gain on sale of investment in Selectide Corporation                --                (1,006)
   Changes in operating assets and liabilities:                                      
     Prepaid expenses and other current assets                         194                  66
     Other assets                                                     (928)                (63)
     Accounts payable                                                  400                  39
     Accrued liabilities                                             2,346               1,433
                                                                  --------            --------
Net cash used in operating activities                              (16,768)             (6,434)
                                                                  --------            --------
                                                                                     
Cash flows from investing activities                                                 
Sales/maturities (purchases) of short-term investments, net         15,755             (13,564)
Purchases of property and equipment                                 (1,074)             (1,413)
Proceeds from sale of investment in Selectide Corporation             --                 2,923
                                                                  --------            --------
Net cash provided by (used in) investing activities                 14,681             (12,054)
                                                                  --------            --------
                                                                                     
Cash flows from financing activities                                                 
Proceeds from issuance of common stock, net                            657              27,397
Repurchase of common stock                                          (2,698)               --
Proceeds from issuance of warrant                                      200                --
Proceeds from lease financing of property and equipment                995               1,338
Payments under capital lease obligations                            (1,044)               (649)
                                                                  --------            --------
Net cash provided by (used in) financing activities                 (1,890)             28,086
                                                                  --------            --------
                                                                                     
Net increase (decrease) in cash and cash equivalents                (3,977)              9,598
Cash and cash equivalents at beginning of period                     8,226              12,599
                                                                  --------            --------
Cash and cash equivalents at end of period                        $  4,249            $ 22,197
                                                                  ========            ========
<FN>

                             See accompanying notes.
</FN>

</TABLE>
                                        5

<PAGE>

                                   SUGEN, Inc.

                          NOTES TO FINANCIAL STATEMENTS

                                   (Unaudited)


1.       Basis of Presentation

         The financial information at September 30, 1996 and for the nine months
         ended  September  30,  1996  and 1995 is  unaudited  but  includes  all
         adjustments  (consisting  only of normal recurring  adjustments)  which
         SUGEN,   Inc.  (the  "Company")   considers   necessary  for  the  fair
         presentation  of the financial  position at such date and the operating
         results and cash flows for those periods.  The  accompanying  condensed
         financial  statements  should be read in conjunction with the financial
         statements  and notes  thereto  for the year ended  December  31,  1995
         included in the  Company's  Form 10-K,  as amended.  The results of the
         Company's  operations  for  any  interim  period  are  not  necessarily
         indicative of the results of the Company's operations for a full fiscal
         year.

2.       Research and Development Agreements

         In January  1996,  the Company and Amgen Inc.  reached an  agreement to
         conclude their research  collaboration one year earlier than originally
         planned due to their changed research  priorities over the three years.
         Under the terms of this  wind-down  agreement,  Amgen made a final cash
         payment to the  Company of $2.5  million  (of which  $1.1  million  was
         advanced in December 1995) and forgave certain advance payments made to
         the Company for future research work.  These amounts have been recorded
         as  wind-down  revenue  in  1996.  Amgen  also  granted  back to  SUGEN
         exclusive  worldwide  rights  to  22  proprietary  signal  transduction
         targets  discovered  in the  course of the  collaboration,  subject  to
         royalty payments back to Amgen with respect to potential future product
         sales.  In addition,  in January 1996 the Company  repurchased  235,000
         shares of its  Common  Stock from Amgen at a price of $11.48 per share,
         thereby reducing Amgen's current holdings of the Company's Common Stock
         to 152,878 shares.  Amgen also purchased in January 1996 for $200,000 a
         warrant  expiring in 2003 to purchase 200,000 shares of Common Stock at
         an exercise price of $15.50 per share.

3.       Accrued Liabilities

         The components of accrued liabilities consist of the following:

                                                     September 30,  December 31,
                                                        1996            1995
                                                     -------------  ------------
                                                           (In thousands)

         Accrued Research & Development Services     $   2,947      $   1,381
         Accrued Compensation                              707            657
         Accrued Professional Fees                         767            344
         Other                                           1,512          1,205
                                                     ---------      ---------
                                                     $   5,933      $   3,587
                                                     =========      =========

                                       6

<PAGE>

                                   SUGEN, Inc.

                          NOTES TO FINANCIAL STATEMENTS

                                   (Unaudited)

4.       Stockholder's Equity

         Option Exercise and Stockholder Note

         In August 1996, an officer of the Company exercised options to purchase
         132,333  shares of Common  Stock at prices  ranging from $6.00 to $7.50
         per share. As consideration for the purchase, the officer issued a full
         recourse  Promissory  Note (the "Note") to the Company.  The Note bears
         interest of 6.84% per annum and is due and payable on August 29,  2001.
         However,  in the  event  that  the  officer's  continous  status  as an
         employee, director or consultant with the Company is terminated for any
         reason  prior to the  full  payment  of the  Note,  the  Note  shall be
         accelerated  and all  remaining  unpaid  principal  and interest  shall
         become due and payable on the 90th day following such  termination.  In
         addition,  the officer has pledged the shares  purchased with this Note
         as collateral.

         Long-Term Objectives Stock Option Plan

         In August 1996,  the Company  amended the options on 180,000  shares of
         Common Stock then  outstanding  under the  Long-Term  Objectives  Stock
         Option Plan to modify the vesting provisions. The amendment resulted in
         deferred  compensation  which will be  amortized  over the new  vesting
         period  of  approximately  five  years.  However,  recognition  of  the
         deferred  compensation  may be accelerated  upon achievement of certain
         milestones.

  5.     Subsequent Events

         Allergan Research and Development Collaboration Agreement

         In October 1996, the Company  established an ophthamology  research and
         development    collaboration   with   Vision    Pharmaceuticals    L.P.
         ("Allergan"),  an affiliate of  Allergan,  Inc. The Company  received a
         $2.0 million initial payment for past research  services,  will receive
         annual research funding and expects to receive additional fees upon the
         achievement of specified milestones and royalties on any product sales.
         In addition,  Allergan,  purchased 191,571 shares of SUGEN Common Stock
         at a price of $20.88  per share in  connection  with the  collaboration
         agreement.  Subsequently,  Allergan  purchased 250,000 shares of Common
         Stock in the  Company's  recently  completed  public  offering as noted
         below.


         Common Stock

         In October 1996, the Company sold 2,000,000  shares of its Common Stock
         in an  underwritten  public  offering  at a price of $12.00  per share,
         resulting in net proceeds of  approximately  $21.7 million.  As part of
         the  offering,  two  of the  Company's  collaborators,  Zeneca  Limited
         ("Zeneca") and Allergan  purchased 509,000 shares and 250,000 shares of
         Common Stock, respectively.

                                       7
<PAGE>

                                   SUGEN, Inc.

Item 2.         MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

     In addition to  historical  information  contained  herein,  the  following
discussion   contains   forward-looking   statements   that  involve  risks  and
uncertainties.  The Company's actual results could differ significantly from the
results discussed in the forward-looking statements. Factors that could cause or
contribute to such  differences  include the factors  discussed below as well as
the factors discussed in the Company's Form 10-K for the year ended December 31,
1995, as amended.

Overview

     SUGEN was founded in July 1991 to discover and develop small molecule drugs
that target specific cellular signal transduction pathways.  These pathways have
been  implicated  in  diseases  such  as  cancer  and  diabetes  as  well  as in
dermatologic,  immunologic,  cardiovascular and neurologic  disorders.  To date,
substantially  all of the Company's  revenue has been pursuant to collaborations
with Zeneca Limited ("Zeneca"),  ASTA Medica  Aktiengesellschaft ("ASTA Medica")
and Amgen Inc.  ("Amgen").  The  Company  intends  to pursue its drug  discovery
programs independently and in collaboration with other pharmaceutical companies.

     In January 1995, the Company established an oncology research collaboration
with Zeneca. The Company received a $5.0 million technology set-up fee, receives
annual research funding and will receive additional fees upon the achievement of
specified  milestones.  In addition,  Zeneca purchased  789,141 shares of Common
Stock at a price of $15.84 per share.

     In December 1995, the Company  established an oncology product  development
collaboration  with ASTA Medica.  The Company received a $4.0 million technology
set-up fee and will receive  additional  fees upon the  achievement of specified
milestones as well as additional  consideration in the form of contract services
for non-collaboration work. In addition, ASTA Medica purchased 431,137 shares of
SUGEN Common Stock for $9.0 million, or $20.88 per share.

     In  January  1996,  the  Company  and  Amgen   terminated   their  research
collaboration one year prior to the scheduled expiration. In connection with the
termination, Amgen paid SUGEN $2.5 million, forgave amounts previously advanced,
and purchased  from SUGEN for $200,000 a warrant to purchase  200,000  shares of
Common  Stock with an exercise  price of $15.50 per share.  In  addition,  SUGEN
repurchased 235,000 of the 387,878 shares of SUGEN Common Stock held by Amgen at
$11.48 per share. The termination  arrangement further provides that the Company
will  make  royalty  and  certain  other  payments  to Amgen in the  event  that
designated potential products are developed and marketed.

     In April 1996, the Company established a second multi-project Collaborative
Research and Development  Agreement ("CRADA") with the National Cancer Institute
("NCI") for the application of SUGEN's proprietary transcript imaging technology
in  order  to  identify  the  differences  in  expression   patterns  of  signal
transduction  genes that  characterize  each of the sixty tumor cell lines which
constitute the NCI's screening panel.  Interesting lead compounds from the NCI's
collection will be tested in SUGEN's target-specific signal transduction assays,
and lead compounds  from SUGEN also will be tested against the NCI panel.  SUGEN
will have the  option to license  discoveries  made  through  this  process  for
adoption into SUGEN's drug discovery programs.

     The Company has not been  profitable  since  inception and expects to incur
substantial losses for the foreseeable future, primarily due to the expansion of
its  research  and  development  programs,  including  preclinical  studies  and
clinical trials.  The Company expects that losses will fluctuate from quarter to
quarter and that such fluctuations may be substantial. As of September 30, 1996,
the Company's accumulated deficit was $52.0 million.

                                       8
<PAGE>

Recent Developments

     In  October  1996,  the  Company  established  an  ophthalmology   research
collaboration with Allergan. The Company received a $2.0 million initial payment
for past research services,  will receive annual research funding and expects to
receive  additional  fees  upon the  achievement  of  specified  milestones  and
royalties on any product sales. In addition,  Allergan  purchased 191,571 shares
of Common Stock at a price of $20.88 per share.

     In October 1996, the Company sold  2,000,000  shares of its common stock in
an underwritten public offering at a price of $12.00 per share, resulting in net
proceeds  of  approximately  $21.7  million.  As  part of the  offering,  Zeneca
purchased  509,000  and  Allergan  purchased  250,000  shares of  Common  Stock,
respectively.

Results of Operations

     The  Company's  revenues for the nine months ended  September 30, 1996 were
$10.3  million,  level  with the same  period in the prior  year.  For the three
months ended September 30, 1996,  revenues were $2.4 million as compared to $3.4
million in the  corresponding  period in the  previous  year.  The  decrease  in
revenue in the third quarter of 1996 compared to the corresponding period in the
previous year is primarily  related to the  recognition of the Zeneca set-up fee
which was fully  recognized  as revenue in 1995.  Revenues  for the nine  months
ended September 30, 1996 included contract revenue from the Zeneca collaboration
and the  final  recognition  of both  the $4.0  million  technology  set-up  fee
received in connection with the ASTA Medica  collaboration  and the $4.3 million
wind-down fee associated with the Amgen termination.  The Company recognizes the
revenue from technology set-up fees and wind-down fees as the related activities
are  performed,  which is  generally  over a  twelve-month  period or less.  The
Company will not recognize any additional revenue under the Amgen collaboration,
and will only recognize  additional revenue under the ASTA Medica  collaboration
upon the achievement of specified  milestones and for contract  services related
to  non-collaboration  work. As a result,  the Company will be required to enter
into new collaborations,  in addition to the Allergan collaboration, in order to
replace the revenues recognized under these collaborations in 1996. No assurance
can be given as to the ability of the Company to enter into such  collaborations
on a timely basis or at all.

     Research  and  development  expenses  increased  to $7.0  million and $21.4
million for the three and nine months ended  September  30, 1996,  respectively,
from $6.0 million and $16.6 million for the  comparable  periods last year.  The
increases  during  1996  are  due to the  expenses  associated  with  additional
personnel  committed to the  Company's  research and  development  programs.  In
addition,  the progression of clinical activities,  including Phase I studies of
the Company's lead anti-cancer compound,  SU101, and the advancement of multiple
programs through preclinical  development  contributed to higher expenses during
1996.  The Company  expects  that its  research and  development  expenses  will
continue to grow  significantly  throughout  the remainder of 1996 and in future
years due to the  hiring  of  personnel,  additional  preclinical  studies,  the
progression of SU101 clinical studies, the initiation of new clinical trials and
pursuant to requirements under the Company's collaborations.

     General and administrative  expenses increased to $4.1 million for the nine
months ended September 30, 1996, from $3.8 million in the same period last year.
However,  general and administrative expenses  decreased to $1.1 million for the
three months ended September 30, 1996 from $1.4 million in the comparable period
in 1995 principally due to lower headcount related expenses (including salaries,
travel,  and similar expenses) and consulting  services during the quarter.  For
the nine months ended  September  30, 1996,  the increase was  primarily  due to
additional  administrative  staffing,  the associated  recruiting and relocation
expenses as well as costs  associated  with the  resignation of an officer.  The
Company  expects that its general and  administrative  expenses will continue to
increase in order to support the Company's research and development efforts.

                                       9
<PAGE>

     Interest  income  increased  to $450,000 and $1.7 million for the three and
nine months ended  September  30,  1996,  respectively,  from  $439,000 and $1.3
million  earned in the  comparable  periods  last year.  The increase was due to
higher  investment  balances  arising  primarily from issuances of the Company's
capital stock.  Interest expense of $167,000 and $521,000 for the three and nine
months ended  September  30, 1996,  respectively,  increased  from  $136,000 and
$345,000 incurred in the same periods last year. This increase was primarily due
to  the  Company's  continued  use  of  capital  lease  financing  for  property
improvements  and  equipment  related to the  expansion of its  facilities.  The
Company  expects that interest  expense will continue to increase in 1996 due to
the  continued  use of  capital  lease  financing  for  equipment  and  facility
improvements.  A $1.0 million gain on the sale of the  Company's  investment  in
Selectide Corporation was included in other income during 1995.

Liquidity and Capital Resources

     The  Company had cash,  cash  equivalents  and  short-term  investments  of
approximately  $33.4 million at September  30, 1996 compared with  approximately
$53.3 million at December 31, 1995. The cash,  cash  equivalents  and short-term
investments  balance at September 30, 1996 does not include the $21.7 million in
net proceeds  received upon the completion of the Company's  follow-on  offering
and the $6.0 million  received  upon the signing of the Allergan  collaboration,
both of  which  were  completed  in  October  1996.  The  decrease  in cash  and
investments during the nine months ended September 30, 1996 was primarily due to
the net loss for the nine  month  period  combined  with the  repurchase  of the
Company's  Common Stock from Amgen, as discussed  above,  partially offset by an
increase in accrued liabilities.

     Through  September 30, 1996, the Company's  principal  sources of financing
were its initial  public  offering of Common Stock,  placements of the Company's
Preferred  and Common Stock and funds  received  under the  Company's  corporate
collaborations.  The Company's  current  principal  sources of liquidity are its
research and development  collaborations with Zeneca, ASTA Medica, and Allergan,
its  cash,  cash  equivalents  and  short-term  investments  and  capital  lease
financing.  The  Company  has a capital  lease  line of $3.5  million  available
through  December 1996 for the purchase of equipment and facility  improvements,
of which $915,000 was available at September 30, 1996.

     The Company has entered into license and  research  agreements  whereby the
Company funds research  projects  performed by others or  in-licenses  compounds
from third  parties.  Some of these  agreements  may require the Company to make
milestone and royalty payments.  Under these programs,  total annual commitments
for research funding are approximately $3.5 million and $2.0 million in 1996 and
1997,  respectively.  A number of these agreements expire in late 1997, however,
the Company anticipates renewing these agreements which will increase the future
commitments of the Company.  Most of these  commitments are cancelable  within a
three to six month  period  and limit the  amounts  payable by the  Company  for
sponsored  research  under the  programs  after  notice of  cancellation  by the
Company.

     From  time  to  time,  the  Company  evaluates  potential   investments  in
complementary businesses,  products, or technologies.  Currently, the Company is
considering modest investments in such complementary businesses during 1996. The
Company  has no other  present  undertakings,  commitments  or  agreements  with
respect to investments in other businesses.

     Net additions of equipment and leasehold  improvements  for the nine months
ended September 30, 1996 were $1.1 million compared to $1.5 million for the same
period last year.  Capital additions have decreased in 1996 due to the timing of
equipment purchases and facility  improvements.  Total capital spending for 1996
is  anticipated  to remain  comparable  to that of the prior  year.  The Company
intends to fund future capital expenditures  principally through lease financing
arrangements.  However,  there can be no assurance  that such  financing will be
available.

                                       10
<PAGE>

     The Company  estimates that its existing  capital  resources,  after giving
effect to the net  proceeds  of its  October  1996  Common  Stock  offering  and
collaboration  agreement  with  Allergan,  together  with facility and equipment
financing,  anticipated revenues from its current  collaborations and net income
from investment  activities,  will be sufficient to fund its planned  operations
into the second half of 1998. The Company anticipates that the funds from future
collaborations will extend this time period.  However, there can be no assurance
that the Company will enter into any such collaborations. In addition, there can
be no assurance that the  underlying  assumed levels of revenue and expense will
prove  accurate.  Whether or not these  assumptions  prove to be  accurate,  the
Company  will  need  to  raise  substantial   additional  capital  to  fund  its
operations.  The  Company  intends  to  seek  such  additional  funding  through
collaborative  arrangements,  public or private  equity or debt  financings  and
capital lease transactions;  however,  there can be no assurance that additional
financing will be available on acceptable  terms or at all. If additional  funds
are raised by issuing equity  securities,  further  dilution to stockholders may
result.  In addition,  in the event that additional  funds are obtained  through
arrangements  with  collaborative  partners,  such  arrangements may require the
Company to relinquish rights to certain of its technologies,  product candidates
or products that the Company would  otherwise  seek to develop or  commercialize
itself.  If  adequate  funds are not  available,  the Company may be required to
delay,  reduce  the  scope  of or  eliminate  one or  more  of its  research  or
development programs, which could have a material adverse effect on the Company.

     The Company is at an early stage of  development  and must be  evaluated in
light of the uncertainties and complications present in a biotechnology company.
The  Company  has been in  existence  only since 1991 and to date a single  drug
candidate  (SU101) has entered human  clinical  testing.  To achieve  profitable
operations  on a  continuing  basis,  the Company,  alone or with  collaborative
partners,  must  successfully  develop,  manufacture,  introduce  and market its
proposed products.  Products,  if any, resulting from the Company's research and
development programs are not expected to be commercially  available for a number
of years,  even if they are  developed  successfully  and  proven to be safe and
effective.  Before obtaining regulatory clearance for the commercial sale of any
of  its  products  under  development,  the  Company  must  demonstrate  through
preclinical  studies and clinical trials that the potential  product is safe and
efficacious  for use in  humans  for each  target  indication.  The  failure  to
adequately  demonstrate  the safety and  efficacy  of a product  under  clinical
development could delay or prevent regulatory clearance of the potential product
and could have a material  adverse effect on the Company.  In addition,  many of
the  Company's  currently  proposed  products  are  subject to  development  and
licensing arrangements with the Company's collaborators.  Therefore, the Company
is dependent on the research and development efforts of these collaborators with
respect to some of its proposed  products  and is entitled  only to a portion of
the revenues,  if any, realized from the commercial sale of any of the potential
products covered by the  collaborations in many  jurisdictions.  The Company has
experienced  significant  operating  losses  since its  inception.  The  Company
expects  to incur  significant  operating  losses at least for the next  several
years and expects  cumulative  losses to increase as the Company's  research and
development efforts,  including  preclinical and clinical testing, are expanded.
Substantially all of the Company's  revenues to date have been received pursuant
to the Company's collaborations. Should the Company or its collaborators fail to
perform in accordance with the terms of any of their agreements,  any consequent
loss of revenue under the agreements could have a material adverse effect on the
Company's results of operations. The foregoing risks reflect the Company's early
stage of  development  and the nature of the  Company's  industry and  potential
products.  Also inherent at the Company's  stage of  development  are a range of
additional risks, including manufactuting  uncertainties,  the Company's lack of
sales  and  marketing   capabilities,   competition,   uncertainties   regarding
protection  of  patents  and  proprietary  rights,   government  regulation  and
uncertainties regarding pharmaceutical pricing and reimbursement.

                                       11
<PAGE>

                           PART II. OTHER INFORMATION



Item 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

         None.

Item 6.  EXHIBITS AND REPORTS ON FORM 8-K

(a)      Exhibits

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

   3.1       Restated Certificate of Incorporation (2)
   3.2(ii)   Bylaws of the Registrant (1)
   3.3       Certificate of Designation of Series A Junior Participating 
                 Preferred Stock of the Registrant (5)
   10.54+    Research and Development Agreement between the Registrant
                 and Arqule, Inc.
   10.55     Extension of Research and License Agreement between the 
                 Registrant and the Max Planck Institut
   10.56     Promissory Note received by the Registrant from Stephen Evans-Freke
   10.57     Agreement for the purchase of Common Stock of the Registrant   
                 by Vision Pharmaceuticals L.P.
   10.58+    Collaboration Agreement by and between the Registrant and
                 Vision Pharmaceuticals L.P.
   10.59+    Extension of Research Agreement between the Registrant and Yissum 
                 Development Company of the Hebrew University
   10.60+++  James L. Tyree Separation Agreement
   27        Financial Data Schedule

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

    +        The Registrant has requested confidential treatment with respect to
                 portions of this Exhibit.
  +++        Exhibit B  of this  Exhibit is incorporated by reference to Exhibit
                10.38 filed in response to Item 6 "Exhibits" of the Registrant's
                Form 10-Q for the quarter ended June 30, 1995.

   (1)       Incorporated by reference to identically numbered exhibits filed in
                 response to Item 16 "Exhibits" of the Company's  Registration
                 Statement on Form S-1, as amended (File Number 33-77074), 
                 which became effective October 4, 1994.
   (2)       Incorporated by reference to identically numbered exhibits filed in
                 response to Item 14 "Exhibits" of the Company's Annual Report
                 of Form 10-K for the year ended December 31, 1994.
   (5)       Filed as an exhibit to the Form 8-K Current Report dated July 26, 
                 1995 and incorporated herein by reference.


(b)   Reports on Form 8-K

         No reports on Form 8-K were filed  during the quarter  ended  September
30, 1996.


                                       12
<PAGE>

                                   SUGEN, Inc.

                                   SIGNATURES


Date:         November 14, 1996           SUGEN, Inc.
      --------------------------------



By:        /s/ Stephen Evans-Freke        By:    /s/ Christine E. Gray-Smith
      --------------------------------        ---------------------------------
       Stephen Evans-Freke                      Christine E. Gray-Smith
       Chairman and                             Senior Director of Finance
       Chief Executive Officer                  (Principal Financial and
                                                  Accounting Officer)



                                       13
<PAGE>

                                   SUGEN, Inc.

                                  EXHIBIT INDEX



Exhibit Number                      Description
- --------------                      -----------
       3.1          Restated Certificate of Incorporation (2)
       3.2(ii)      Bylaws of the Registrant (1)
       3.3          Certificate of Designation of Series A Junior Participating
                        Preferred Stock of the Registrant (5)
       10.54+       Research and Development Agreement between the Registrant
                        and Arqule, Inc.
       10.55       Extension of Research and License Agreement between the  
                        Registrant and the Max Planck Institut
       10.56        Promissory Note received by the Registrant from Stephen 
                        Evans-Freke
       10.57        Agreement for the purchase of Common Stock of the Registrant
                        by Vision Pharmaceuticals L.P.
       10.58+       Collaboration Agreement by and between the Registrant and
                        Vision Pharmaceuticals L.P.
       10.59+       Extension of Research Agreement between the Registrant and 
                        Yissum Development Company of the Hebrew University
       10.60+++     James L. Tyree Separation Agreement
       27           Financial Data Schedule

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

      +        The Registrant has requested  confidential treatment with respect
                to portions of this Exhibit.
    +++        Exhibit B of this Exhibit is incorporated by reference to Exhibit
                10.38 filed in response to Item 6 "Exhibits" of the Registrant's
                Form 10-Q for the quarter ended June 30, 1995.
     (1)       Incorporated  by reference to identically numbered exhibits filed
                in response to Item 16 "Exhibits" of the Company's  Registration
                Statement on Form S-1, as amended (File Number 33-77074),  which
                became effective October 4, 1994.
     (2)       Incorporated by  reference to identically numbered exhibits filed
                in response to Item 14 "Exhibits" of the Company's Annual Report
                of Form 10-K for the year ended December 31, 1994.
     (5)       Filed as an  exhibit to the Form 8-K  Current  Report  dated July
                26, 1995 and incorporated herein by reference.

                                       14

                                                                   EXHIBIT 10.54




           Certain   confidential   information   contained  in  this
           document, marked by brackets, is filed with the Securities
           and  Exchange  Commission  pursuant  to Rule  24b-2 of the
           Securities Exchange Act of 1934, as amended.



                       RESEARCH AND DEVELOPMENT AGREEMENT

                                     between

                                  ARQULE, INC.

                                       and

                                   SUGEN, INC.



<PAGE>

                                TABLE OF CONTENTS

                                                                            Page

1.  Definitions.............................................................. 1.
    1.1      "Active Homolog"................................................ 1.
    1.2      "Active Sugen Compound"......................................... 1.
    1.3      "Affiliate"..................................................... 1.
    1.4      "Array"......................................................... 2.
    1.5      "Base Rate of Interest"......................................... 2.
    1.6      "Confidential Information"...................................... 2.
    1.7      "Directed Array"................................................ 2.
    1.8      "Directed Array Program......................................... 2.
    1.9      "Field"......................................................... 2.
    1.10     "Licensed Compound"............................................. 2.
    1.11     "Materials"..................................................... 2.
    1.12     "Mapping Array"................................................. 2.
    1.13     "Net Sales"..................................................... 3.
    1.14     "Net Sales Price"............................................... 3.
    1.15     "Party.......................................................... 3.
    1.16     "Patent Rights.................................................. 3.
    1.17     "Preclinical Development"....................................... 3.
    1.18     "Proprietary Materials"......................................... 3.
    1.19     "Research Committee"............................................ 3.
    1.20     "Research Plan"................................................. 3.
    1.21     "Research Program".............................................. 4.
    1.22     "Research Results".............................................. 4.
    1.23     "Royalty-Bearing Product"....................................... 4.
    1.24     "Royalty Period"................................................ 4.
    1.25     "Sublicensee"................................................... 4.
    1.26     "Sublicense Revenue............................................. 4.
    1.27     "Substantial Homology".......................................... 4.
    1.28     "Sugen Compound"................................................ 4.
    1.29     "Sugen Derivative Compound"..................................... 4.
    1.30     "Target"........................................................ 5.

2.  Management of Research Program........................................... 5.
    2.1      Research Committee.............................................. 5.
             2.1.1    Creation of Research Committee......................... 5.
             2.1.2    Meetings of the Research Committee..................... 5.
             2.1.3    Decisions of Research Committee........................ 5.
             2.1.4    Responsibilities of Research Committee................. 5.
             2.1.5    Research Committee Reports............................. 6.
             2.1.6    Business Deadlock...................................... 6.

                                       i.

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)
                                                                            Page

3.  License Grants........................................................... 6.
    3.1      Screening Licenses.............................................. 6.
    3.2      Development Licenses............................................ 6.
    3.3      Commercialization Licenses...................................... 6.
             3.3.1    Grant of License by ArQule to Sugen.................... 6.
             3.3.2    Grant of Licenses by Sugen to ArQule................... 7.
             3.3.3    Other Licenses......................................... 7.
    3.4      Diligence....................................................... 7.

4.  Collaborative Research Program........................................... 7.
    4.1      Nature of Relationship.......................................... 7.
    4.2      Conduct of Research Program..................................... 7.
    4.3      Directed Array Program.......................................... 8.
             4.3.1    Conduct of Directed Array Program...................... 8.
             4.3.2    Completion of Testing.................................. 8.
    4.4      Designation of Licensed Compounds............................... 8.
    4.5      Disclosure of Research Results.................................. 8.
    4.6      Research Records................................................ 8.
    4.7      Payment of Costs and Expenses................................... 9.

5.  Ownership of Sugen Compounds............................................. 9.

6.  Intellectual Property Rights............................................. 9.
    6.1      Ownership of Patent Rights...................................... 9.
    6.2      Management of Joint Patent Rights...............................10.
    6.3      Cooperation of the Parties......................................10.
    6.4      Infringement by Third Parties...................................10.

7.  Royalties; Sublicense Revenues; Reports..................................11.
    7.1      Royalty Payments................................................11.
             7.1.1    Sugen Royalty Payments.................................11.
             7.1.2    ArQule Payments........................................11.
    7.2      Reports and Payments............................................11.
    7.3      Payments in U.S. Dollars........................................11.
    7.4      Payments in Other Currencies....................................12.
    7.5      Late Payments...................................................12.

8.  Records; Inspection......................................................12.
    8.1      Records.........................................................12.


                                       ii.

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)
                                                                            Page
    8.2      Inspection......................................................12.

9.  Proprietary Materials....................................................12.
    9.1      Ownership of Proprietary Materials..............................12.
    9.2      Use of Proprietary Materials....................................13.
    9.3      Transfer of Proprietary Materials...............................13.
    9.4      Disposition of Unused Proprietary Materials.....................13.

10. Confidential Information.................................................13.
    10.1     Confidential Information........................................13.

11. Term and Termination.....................................................15.
    11.1     Term............................................................15.
    11.2     Termination for Breach..........................................15.
    11.3     Force Majeure...................................................15.
    11.4     Effect of Termination...........................................15.
    11.5     Survival of Provisions..........................................15.

12. Miscellaneous............................................................15.
    12.1     Publicity.......................................................15.
    12.2     Relationship of Parties.........................................15.
    12.3     Dispute Resolution..............................................16.
    12.4     Counterparts....................................................16.
    12.5     Headings........................................................16.
    12.6     Binding Effect..................................................16.
    12.7     Assignment......................................................16.
    12.8     Notices.........................................................16.
    12.9     Amendment and Waiver............................................17.
    12.10    Governing Law...................................................17.
    12.11    Severability....................................................17.
    12.12    Entire Agreement................................................18.
    12.13    Indemnification.................................................18.




                                      iii.


<PAGE>

                        RESEARCH COLLABORATION AGREEMENT

         THIS RESEARCH  COLLABORATION  AGREEMENT  (this  "Agreement") is entered
into as of September 4, 1996 (the "Effective Date") by and between ARQULE, INC.,
a Delaware  corporation  ("ArQule"),  and SUGEN,  INC.,  a Delaware  corporation
("Sugen").


                                    RECITALS

         WHEREAS,  Sugen is engaged in research  involving  the  evaluation  and
analysis  of  compounds  related  to the  inhibition  of  tyrosine,  serine  and
threonine kinases;

         WHEREAS,  ArQule has developed certain proprietary  technology enabling
it to  synthesize  arrays of small organic  molecules  suitable for screening in
molecular assays;

         WHEREAS,  Sugen and ArQule desire to collaborate  on research  directed
towards the  discovery  and  development  of new  compounds  by testing  certain
compound  arrays  produced by ArQule from  compounds  provided by Sugen  against
selected chemical targets specified by Sugen; and

         WHEREAS,  ArQule has developed certain proprietary  compounds which can
be used to  facilitate  the  discovery and  development  of new  compounds  from
compounds provided by Sugen; and

         WHEREAS,  Sugen and ArQule desire to commercialize any new compounds so
developed on the terms and subject to the conditions provided herein.

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

1.       DEFINITIONS.

         1.1 "Active  Homolog"  shall mean any Sugen  Derivative  Compound  that
exhibits  Substantial  Homology  with an Active Sugen  Compound as determined by
Sugen using appropriate business and scientific criteria.

         1.2 "Active Sugen  Compound" shall mean any Sugen  Derivative  Compound
which exhibits  confirmed  significant  functional  activity against a Target as
defined by Sugen using appropriate business and scientific  criteria;  provided,
however, that Sugen shall receive input and guidance from the Research Committee
with  respect to the number of Active Sugen  Compounds  that are subject to this
Research Program.

         1.3  "Affiliate"  shall mean any person or entity  which,  directly  or
indirectly,  controls,  or is  controlled  by, a  party.  For  purposes  of this
definition,  "control" means the ownership, directly or indirectly, of more than
fifty percent (50%) of the outstanding equity securities of


                                       1.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

a corporation entitled to vote in the election of directors or a more than fifty
percent (50%)  interest in the net assets or profits of an entity which is not a
corporation.

         1.4      "Array" shall mean a set of [                                ]
that are synthesized  by ArQule using its proprietary technology and arranged in
a format such as a microtiter screening plate.

         1.5 "Base Rate of  Interest"  shall mean the rate of interest  declared
from time to time by the Bank of Boston as being its prime rate.

         1.6 "Confidential Information" shall mean any confidential,  secret, or
proprietary  information  regardless of whether such  information is in written,
oral  (provided any such oral  information  is reduced to writing  within thirty
(30)  days),  electronic,  or other  form (a)  resulting  from or related to the
Research  Program or (b)  relating to the  scientific  and  business  affairs of
either  Party  (and  not  otherwise  described  in  clause  (a))  and  which  is
specifically designated as "Confidential".  Such Confidential  Information shall
include,  without  limitation,  the results of any tests conducted in connection
with the Research Program, all Research Committee reports, the screening systems
used to  identify  Active  Sugen  Compounds  and the  compositions  of the Sugen
Compounds and Sugen Derivative Compounds. Such Confidential Information may also
include, without limitation, trade secrets, know-how, inventions, technical data
or specifications,  testing methods, business or financial information, research
and  development  activities,  product and  marketing  plans,  and  customer and
supplier information.

         1.7 "Directed Array" shall mean any Array comprised of Sugen Derivative
Compounds synthesized by ArQule under the Directed Array Program as set forth in
Section 4.3.

         1.8 "Directed Array Program" shall mean the Directed Array component of
the Research Program as set forth in Section 4.3.

         1.9  "Field"  shall  mean each  field  described  on Exhibit B attached
hereto.

         1.10 "Licensed Compound" shall mean any Active Sugen Compound or Active
Homolog  thereto with respect to which Sugen,  using one or more of the criteria
set forth on Exhibit C hereto, has elected to conduct Preclinical Development.

         1.11 "Materials"  shall mean any tangible research  materials,  whether
biological, chemical, physical, or otherwise.

         1.12  "Mapping  Array"  shall mean an Array of [                      ]
(which may include, without limitation, [                 ], but may not include
[                        ] and which are licensed from time to time by ArQule to
third parties on a non-exclusive basis for [                         ].


                                       2.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         1.13  "Net  Sales"  shall  mean  the   aggregate  Net  Sales  Price  of
Royalty-Bearing Products in any Royalty Period.

         1.14 "Net Sales Price" shall mean the gross amount received on sales by
either Party and its Affiliates of Royalty-Bearing Products, less the following:
[

                                                                       ]  In any
transfers of Royalty-Bearing  Products between such Party and an Affiliate,  the
Net  Sales  Price  shall  be   calculated   based  on  the  final  sale  of  the
Royalty-Bearing  Product to an independent  third party.  In the event that such
Party receives non-monetary  consideration for any Royalty-Bearing Products, the
Net Sales Price shall be  calculated  based on the average price charged by such
Party for such Royalty-Bearing Products during the preceding Royalty Period.

         1.15  "Party"  means  ArQule or Sugen or their  respective  Affiliates;
"Parties" means ArQule and Sugen and their respective Affiliates.

         1.16  "Patent  Rights"  shall  mean all Valid  Claims of all issued and
unexpired  patents and reissues,  reexaminations,  extensions and  supplementary
protection  certificates  thereof and all patent applications and any divisions,
continuations,  or continuations-in-part thereof or patents issuing thereon. For
the purposes of this Section,  "Valid Claim" shall mean either (a) a claim of an
issued patent that has not been held  unenforceable or invalid by an agency or a
court of competent  jurisdiction in any  unappealable or unappealed  decision or
(b) a claim that is based upon a specification  of a pending patent  application
that has not been  abandoned  or finally  rejected  without the  possibility  of
appeal or refiling and that has been pending in the U.S.  Patent Office for less
than five (5) years or in the  Japanese  Patent  Office  for less than seven (7)
years.

         1.17 "Preclinical  Development"  shall mean, with respect to a Licensed
Compound,  the testing of the Licensed Compound in appropriate  systems in order
to meet regulatory  requirements  for a United States  Investigational  New Drug
Application  which,  except  as  may be  otherwise  agreed  to by  the  Research
Committee,  shall include one or more of the  following:  (a)  demonstration  of
potency  and  efficacy in  validated  animal  models,  (b)  compiling  an animal
pharmacology  profile, (c) testing of acute toxicity and (d) toxicology testing,
including  histopathology  of vital organs,  all as appropriate  for the disease
indication and compound selected.

         1.18  "Proprietary  Materials"  shall  mean  any  Materials  that  were
developed  by a Party  prior  to or  outside  the  performance  of the  Research
Program;  provided,  however, that Proprietary Materials shall not include Sugen
Derivative Compounds, Active Sugen Compounds or any Active Homologs thereto.

         1.19 "Research  Committee" shall mean the Research Committee  described
in Section 2.1.

         1.20  "Research  Plan" shall mean the Research Plan attached  hereto as
Exhibit A, as revised by the Research Committee from time to time.


                                       3.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         1.21 "Research  Program" shall mean the collaborative  research program
described in Section 4 of this Agreement.

         1.22  "Research   Results"   shall  mean  any   inventions   (including
Materials), laboratory notes, technical data or specifications, test results, or
other information or materials that arise as a result of the Research Program.

         1.23  "Royalty-Bearing  Product" shall mean a product  covered by Joint
Patent  Rights  containing  as one of its  constituents  (a)  any  Active  Sugen
Compound and/or any Active Homolog thereto; (b) any other compound discovered or
designed by Sugen as a direct result of information  provided by ArQule to Sugen
under the  Directed  Array  Program;  or (c) any other  compound  discovered  or
designed by ArQule or any third party customer or  collaborator of ArQule from a
Sugen Compound or a Sugen Derivative Compound.

         1.24 "Royalty  Period" shall mean every  calendar  quarter,  or partial
calendar  quarter,  commencing  on the date of the  first  commercial  sale of a
Royalty-Bearing  Product in any country and  continuing  until the last calendar
quarter during which any Royalty-Bearing Product is sold in any country.

         1.25 "Sublicensee" shall mean any non-Affiliate third party licensed by
either Party to make, use or sell any Royalty-Bearing Product.

         1.26 "Sublicense  Revenue" shall mean any payments that are received by
a Party from a Sublicensee, including all initial payments, royalties, milestone
payments and other periodic  payments in connection with the sublicensing of any
Royalty-Bearing Product, but excluding [






                                                 ]

         1.27  "Substantial  Homology"  shall mean an alteration  from an Active
Sugen Compound at [         ] sites where no more than [     ] atoms are altered
in total; e.g., [
                           ]

         1.28 "Sugen  Compound"  shall mean any  chemical  compound  provided by
Sugen or its Affiliates to ArQule under the Directed Array Program.  Examples of
such  compounds  are shown in Exhibit D, which may be updated by Sugen from time
to time in writing.

         1.29  "Sugen  Derivative  Compound"  shall  mean  a  chemical  compound
synthesized by ArQule under the Directed Array Program in [         ] steps from
another chemical compound by a process of [        ] of [        ] component


                                       4.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

wherein [   ] structural feature is retained at each process step. The number of
intermediate  steps or  compounds  is not  relevant to the  classification  of a
compound as a Sugen  Derivative  Compound.  A compound need not have  structural
similarity to another  compound in order to be classified as a Sugen  Derivative
Compound.  The term  excludes  those  compounds  synthesized  by Sugen  prior to
signing this Agreement.

         1.30 "Target"  shall mean any target in the Field selected by Sugen for
which Sugen has certain proprietary technology and/or expertise.

2.       MANAGEMENT OF RESEARCH PROGRAM.

         2.1      Research Committee.

                  2.1.1  Creation of  Research  Committee.  The  Parties  hereby
create a Research Committee which shall consist of [  ] members, [   ] of which
shall be designated by ArQule and [   ] of which shall be designated by Sugen at
any time. The chairperson of the Research Committee shall be designated annually
on an alternating  basis between the Parties,  who shall  initially be Joseph C.
Hogan, Jr. The Party not designating the chairperson  shall designate one of its
representatives as secretary to the Research Committee for such year.
Each member of the Research Committee shall have equal voting rights.

                  2.1.2 Meetings of the Research Committee.  Regular meetings of
the Research Committee shall be held with such frequency as the Parties may deem
appropriate,  at such times and places as the members of the Research  Committee
shall from time to time agree. Special meetings of the Research Committee may be
called by  either  Party on ten (10)  days'  written  notice to the other  Party
unless notice is waived by the Parties. All meetings shall alternate between the
offices of the Parties unless the Parties otherwise agree. The chairperson shall
be responsible for sending notice of meetings to all members.

                  2.1.3  Decisions  of  Research  Committee.  A  quorum  of  the
Research  Committee shall be present at any meeting of the Research Committee if
at least one  representative  of each Party is present at such meeting in person
or by telephone. If a quorum exists at any meeting, the unanimous consent of all
members of the  Research  Committee  present at such meeting is required to take
any action on behalf of the Research  Committee.  Unless otherwise  specifically
stated to the  contrary  herein,  no  individual  Party shall  purport to act on
behalf of the other Party unless and then only to the extent authorized to do so
by the Research Committee.

                  2.1.4    Responsibilities of Research Committee.  The Research
Committee  shall  be  responsible for the day-to-day conduct and progress of the
Research Program, including, without limitation:

                           (i)      directing  and  administering  the  Research
                                    Program;

                           (ii)     providing  a  forum  for  the   exchange  of
                                    scientific  information among the scientists
                                    participating in the Research Program;


                                       5.

<PAGE>

                           (iii)    reviewing test reports  provided by Sugen as
                                    to  the  significant   functional   activity
                                    derived  from testing  Directed  Arrays and,
                                    based  on  such  results,   recommending  to
                                    ArQule   whether   to   develop   additional
                                    Directed   Arrays  for  any   Active   Sugen
                                    Compound;

                           (iv)     providing  guidance to Sugen with respect to
                                    the number of Active  Sugen  Compounds  that
                                    are subject to this Research Program;

                           (v)      resolving   matters   involving   scientific
                                    questions; and

                           (vi)     updating the Research Plan.

                  2.1.5  Research  Committee  Reports.   Within  ten  (10)  days
following each meeting of the Research Committee held pursuant to Section 2.1.2,
the secretary of the Research  Committee  shall prepare and send to each Party a
written report of actions taken at the meeting in such form and containing  such
detail as shall be determined by the Research Committee.

                  2.1.6  Business  Deadlock.  In the  event  that  the  Research
Committee  cannot  agree  with  respect  to a  matter  that  is  subject  to its
decision-making  authority, then the matter shall be resolved in accordance with
Section 12.3.

3.       LICENSE GRANTS.

         3.1  Screening  Licenses.  ArQule  hereby grants to Sugen an exclusive,
royalty-free  license  (without the right to  sublicense)  to (i) test any Sugen
Derivative Compounds for significant  functional activity against Targets within
the  Field  and (ii) and to  conduct  such  additional  tests on any such  Sugen
Derivative Compounds within the Field prior to Preclinical  Development as Sugen
may from time to time determine.  Notwithstanding the foregoing,  Sugen may from
time to time deliver Sugen Derivative  Compounds to one or more third parties so
as to allow such third  parties to perform  testing and  analytical  work on any
such Sugen Derivative Compounds;  provided, that, prior to delivery of any Sugen
Derivative  Compounds to any such third  party,  Sugen and each such third party
enter into a materials  transfer  agreement in a form  reasonably  acceptable to
ArQule.

         3.2  Development  Licenses.  Upon  the  identification  by Sugen of any
Active Sugen Compound or any Active  Homolog  thereto and the  determination  by
Sugen that such Active  Sugen  Compound  or any Active  Homolog  thereto  should
properly be  designated  as a Licensed  Compound,  ArQule  shall grant to Sugen,
under any intellectual property rights covering the composition,  manufacture or
use of such Licensed  Compound,  an exclusive,  royalty-free  license to conduct
Preclinical Development of such Licensed Compound.

         3.3      Commercialization Licenses.

                  3.3.1    Grant of  License  by ArQule to Sugen.  ArQule hereby
grants to  Sugen an exclusive,  royalty-bearing license (with the right to grant
sublicenses) (i) to make or have


                                       6.

<PAGE>

made Licensed  Compounds for use,  distribution  and sale within the Field,  and
(ii) to distribute for sale and sell Licensed Compounds within the Field.

                  3.3.2  Grant of  Licenses  by Sugen to  ArQule.  Sugen  hereby
grants to ArQule an  exclusive,  royalty-bearing,  worldwide  license  (with the
right to grant sublicenses) to incorporate Sugen Derivative  Compounds which are
not Sugen Compounds, Active Sugen Compounds or Licensed Compounds in any Mapping
Arrays to be provided by ArQule to its third party  customers and  collaborators
for screening only outside the Field;  provided,  that, prior to delivering such
Sugen  Derivative  Compounds to any such third party  customer or  collaborator,
ArQule and each such third party customer or collaborator enter into a materials
transfer agreement in a form reasonably  acceptable to Sugen. In connection with
the grant of the license described in this Section 3.3.2,  Sugen agrees that (i)
ArQule may grant  royalty-bearing  world-wide licenses solely under Joint Patent
Rights to any  third  parties  to  commercialize  products  derived  from  Sugen
Derivative  Compounds which are not Sugen  Compounds,  Active Sugen Compounds or
Licensed  Compounds  included in any such Mapping Arrays outside the Field, (ii)
ArQule  may  conduct  Preclinical  Development  of  any  such  Sugen  Derivative
Compounds or products  derived  therefrom but may not itself  commercialize  any
such Sugen Derivative Compounds or products derived therefrom, (iii) Sugen shall
not grant to any third party a license to permit Sugen  Derivative  Compounds to
be included in any screening  program  competitive  with ArQule's  Mapping Array
Program and (iv)  Arqule  shall not grant to any third party a license to permit
Sugen Derivative  Compounds or any compound  discovered or designed by ArQule or
any third party  customer or  collaborator  of ArQule from a Sugen Compound or a
Sugen Derivative Compound to be used within the Field.

                  3.3.3 Other  Licenses.  Each Party hereby agrees that no other
license is granted by either Party to any of its existing or future intellectual
property other than as is expressly described in this Agreement.

         3.4 Diligence.  ArQule agrees to use reasonable  commercial  efforts to
develop and market Mapping  Arrays based on or  incorporating  Sugen  Derivative
Compounds for which it has obtained a license under Section 3.3.2, using a level
of effort  consistent  with that used for other Mapping  Arrays  having  similar
commercial potential.

4.       COLLABORATIVE RESEARCH PROGRAM.

         4.1 Nature of Relationship.  The purpose of this research collaboration
is to identify Sugen Derivative  Compounds which demonstrate  certain functional
activity  against  selected  Targets and to develop  and/or license to corporate
parties compounds so identified within the Field.

         4.2  Conduct  of  Research  Program.   Unless  earlier   terminated  in
accordance  with Section 11 of this  Agreement,  the Research  Program  shall be
conducted by the Parties in accordance with the Research Plan attached hereto as
Exhibit  A, as  amended  from  time to time by the  Research  Committee,  and as
described in this Section 4.


                                       7.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         4.3      Directed Array Program.

                  4.3.1 Conduct of Directed Array  Program.  Under the direction
of the Research  Committee and in accordance with the Research Plan, ArQule will
synthesize  Sugen  Derivative  Compounds from Sugen Compounds in such quantities
and at such times as shall be determined by the Research Committee in accordance
with Section 2.1.4.  The  Parties intend that ArQule will produce  approximately
[               ] of each Sugen  Derivative  Compound  in the  Directed  Arrays,
subject to the availability of the original Sugen Compounds;  provided, however;
that the amount of each Sugen Derivative  Compound that ArQule actually produces
under the Directed  Array Program will  ultimately be determined by the Research
Committee.  Promptly  upon its receipt of any such Directed  Array,  Sugen shall
commence testing of such Directed Array for activity against Targets;  provided,
however,  that it is the intention of the Parties that (i) the initial  shipment
of Directed  Arrays based on Sugen  Compounds be delivered by ArQule to Sugen on
or  before  [             ] and  (ii) the  initial  screening  of such  Directed
Arrays be completed by Sugen on or before [                    ]. Promptly  upon
the  completion  by Sugen of its  testing of each  Directed  Array,  Sugen shall
provide the  Research  Committee  with notice of the  discovery  of Active Sugen
Compounds, together with relevant information concerning the functional activity
identified. Under the direction of the Research Committee and in accordance with
the  Research  Plan,  ArQule  will  thereafter  provide  Sugen  with  additional
quantities  [                     ] of each such  Active  Sugen  Compound  so as
to enable Sugen to conduct additional testing or Preclinical Development of such
Active Sugen Compound.

                  4.3.2  Completion of Testing.  The Parties shall  continue the
procedure  described in Section 4.3.1 for each Active Sugen  Compound  until the
earliest to occur of (i) the  determination by Sugen to cease further testing of
such  Active  Sugen  Compound,  or (ii) the  termination  of this  Agreement  in
accordance with Section 11.

         4.4 Designation of Licensed  Compounds.  The Parties hereby acknowledge
and agree that Sugen, in making its determination as to whether to designate any
Active Sugen Compound as a Licensed Compound,  shall use the good scientific and
business criteria set forth on Exhibit C attached hereto, it being the intention
of the Parties  that such  criteria  shall be used as the basis for  determining
whether  any  Active  Sugen  Compound  shall  also be  designated  as a Licensed
Compound.

         4.5 Disclosure of Research  Results.  Each Party agrees to promptly and
regularly  communicate all Research Results to the other Party. Without limiting
the  generality  of the  foregoing,  each Party  agrees to provide the  Research
Committee  with  quarterly  reports  detailing  all tests  conducted and results
obtained by such Party in connection with the Research Program.

         4.6 Research  Records.  Each Party shall prepare and maintain  adequate
records,  including  bound  laboratory  notebooks  maintained in accordance with
standard scientific  procedures,  containing all appropriate data reflecting the
Research  Results.  In  addition,  each Party  shall  retain  under  appropriate
conditions  any  necessary or desirable  samples of  Materials  that  constitute
Research Results.


                                       8.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         4.7 Payment of Costs and Expenses.  Each Party shall bear the costs and
expenses of its respective  activities in connection  with the Research  Program
and shall promptly make payments to third parties arising therefrom.

5.       OWNERSHIP OF SUGEN COMPOUNDS.

         All Sugen Compounds shall be owned by Sugen or its Affiliates,  except,
and only to the extent that, with respect to the Directed Array Program,  ArQule
can show that any such compound [



                                                                      ] prior to
Sugen's description of such Sugen Compound in any written documentation.

6.       INTELLECTUAL PROPERTY RIGHTS.

         6.1      Ownership of Patent Rights.

                  (a) Sugen  Patent  Rights.  Any Patent  Rights filed by either
         Party  after  the  Effective  Date of  this  Agreement  claiming  Sugen
         Compounds will be owned solely by Sugen.

                  (b) Joint Patent Rights. Any Patent Rights conceived after the
         Effective Date of this Agreement filed by either Party [



                                                          ]  Each of the Parties
         hereby agrees that it will not practice or license  such  Joint  Patent
         Rights to any third party except as follows:  [



                                                                               ]
         provided,  however,  that if any such  license  involves  an  exclusive
         license to commercialize a product covered by Joint Patent Rights,  the
         Party  licensing  such Joint Patent Rights shall notify the other Party
         prior to the execution of any such license.

                  (c)  Breach.  If  either  Party  shall  practice  or grant any
         license to a third party in  violation  of Section  6.1(b)  above,  the
         licensed  Joint  Patent  Rights  will  immediately  vest  solely in the
         non-granting  Party and the license granted will be  automatically  and
         immediately  rescinded.  The granting Party may prevent such vesting by
         obtaining the written consent of the non-granting  Party, which consent
         will not be unreasonably withheld.

                                       9.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                  (d) Other Patent  Rights.  All other  Patent  Rights are owned
         according to existing laws.

         6.2  Management  of Joint  Patent  Rights.  In the case of Joint Patent
Rights, the Parties shall agree on the allocation of responsibility for, and the
expense of, the preparation,  filing, prosecution,  and maintenance of any Joint
Patent  Rights  claiming  such  inventions.  In the  event  of any  disagreement
concerning any Joint Patent Rights, the matter shall be resolved by the Research
Committee  or, in the  absence  thereof,  by the  President  of  ArQule  and the
Executive Vice President-Research of Sugen. The Party controlling a Joint Patent
Right  shall  consult  with  the  other  party  as to the  preparation,  filing,
prosecution,  and maintenance of such Joint Patent Right reasonably prior to any
deadline or action with the U.S. Patent & Trademark Office or any foreign patent
office,  and shall  furnish to the other Party copies of all relevant  documents
reasonably  in  advance  of such  consultation.  In the  event  that  the  Party
controlling a Joint Patent Right desires to abandon such Joint Patent Right,  or
if  the  Party  assuming   control  of  a  Joint  Patent  Right  later  declines
responsibility  for such Joint Patent Right, the controlling Party shall provide
reasonable  prior written notice to the other Party of such intention to abandon
or decline  responsibility,  and such other Party  shall have the right,  at its
expense, to prepare, file, prosecute, and maintain such Joint Patent Rights.

         6.3  Cooperation  of the  Parties.  The  Parties  hereby  agree to file
appropriate  applications  for  Patent  Rights  prior to taking any  action,  or
failing to take any action,  that would  jeopardize  or prevent the obtaining of
commercially reasonable patent protection in the [
                           ] under the Patent Rights.  Each Party further agrees
to  cooperate  fully  in  the preparation, filing, and prosecution of any Patent
Rights under this Agreement.  Such cooperation includes, but is not limited to:

                  (a)  executing  all papers and  instruments,  or requiring its
         employees or agents,  to execute such papers and instruments,  so as to
         effectuate  the  ownership  of Patent  Rights set forth in Section  6.1
         above and to  enable  the  other  Party to apply  for and to  prosecute
         patent applications in any country;

                  (b) promptly  informing the other Party of any matters  coming
         to a Party's  attention  that may affect the  preparation,  filing,  or
         prosecution of any such patent applications; and

                  (c) undertaking no actions that are potentially deleterious to
         the preparation, filing, or prosecution of such patent applications.

         6.4 Infringement by Third Parties. ArQule and Sugen shall each promptly
notify the other in writing of any alleged or threatened infringement by a third
party of any Joint Patent Right of which they become  aware.  The Parties  shall
consult concerning the action(s) to be taken.


                                       10.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

7.       ROYALTIES; SUBLICENSE REVENUES; REPORTS.

         7.1      Royalty Payments.

                  7.1.1 Sugen Royalty Payments. In consideration of the licenses
granted  to Sugen  hereunder,  Sugen  shall pay to ArQule,  during  the  Royalty
Period, as applicable (A) (i) a royalty of [      ] of Net Sales by Sugen or any
Affiliate of any Royalty-Bearing Product in the United States and (ii) a royalty
of [  ] of Net Sales by Sugen or any Affiliate of any Royalty-Bearing Product in
all other countries or (B) [
             ] of any Sublicense Revenues received by Sugen from any Sublicensee
in  connection  with its  sublicensing  of any  Royalty-Bearing  Product  in any
country.

                  7.1.2 ArQule Payments. In consideration of the license granted
to ArQule hereunder, ArQule shall pay to Sugen, during the Royalty Period, [   ]
of any Sublicense  Revenue received by ArQule from any Sublicensee in connection
with its sublicensing of any Royalty-Bearing Product.

         7.2 Reports and Payments. Within [  ] days after the conclusion of each
Royalty Period,  each Party shall deliver to the other Party a report containing
the following information:

                  [






                                                         .]

All such  reports  shall be  maintained  in  confidence  by the  Parties.  If no
royalties  are due to any Party for any  reporting  period,  the report shall so
state.  Concurrent with each such report,  the Party delivering the report shall
remit to the other Party any payment due for the applicable  Royalty Period with
the method of payment mutually agreed to by the Parties.  All amounts payable to
the Parties  under this Section 7.2 will first be  calculated in the currency of
sale and then  converted into U.S.  dollars in accordance  with Section 7.3, and
such  amounts  shall  be  paid  without  deduction  of  any  withholding  taxes,
value-added taxes, or other charges applicable to such payments.

         7.3 Payments in U.S.  Dollars.  All  payments due under this  Agreement
shall,  except as  provided in Section  7.4 below,  be payable in United  States
dollars.  Conversion  of foreign  currency to U.S.  dollars shall be made at the
average  conversion  rate existing in the United States (as reported in the Wall
Street  Journal)  during the last  calendar  quarter  preceding  the  applicable
calendar  quarter.  Such  payments  shall  be  without  deduction  of  exchange,
collection, or other charges.


                                       11.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         7.4  Payments in Other  Currencies.  If by law,  regulation,  or fiscal
policy of a  particular  country,  conversion  into  United  States  dollars  or
transfer of funds of a  convertible  currency to the United States is restricted
or forbidden,  the paying Party shall give the other Party prompt written notice
of such restriction, which notice shall satisfy the [                  ] payment
deadline  described in Section 7.2.  Such paying Party shall pay any amounts due
the other Party  through  whatever  lawful  methods such other Party  reasonably
designates;  provided, however, that if such other Party fails to designate such
payment method within [          ] days after it is notified of the restriction,
then the paying Party may deposit  such payment in local  currency to the credit
of the other Party in a recognized  banking  institution  selected by the paying
Party and  identified  by written  notice to the other  Party,  and such deposit
shall  fulfill  all  obligations  of the  paying  Party to the other  Party with
respect to such payment.

         7.5 Late  Payments.  Any  payments by any Party that are not paid on or
before the date such payments are due under this Agreement  shall bear interest,
to the extent permitted by law, at [           ] above the Base Rate of Interest
calculated based on the number of days that payment is delinquent.

8.       RECORDS; INSPECTION.

         8.1 Records. Each Party shall maintain complete and accurate records of
(i) all Royalty-Bearing  Products  commercialized by or through such Party under
this  Agreement,  (ii) all Net Sales and  Sublicense  Revenues  received by such
Party in connection with each such Royalty-Bearing Product and (iii) any amounts
payable to such Party in relation to each such  Royalty-Bearing  Product,  which
records shall contain sufficient information to permit each Party to confirm the
accuracy of any  payments  distributed  in  accordance  with Section 7.1 of this
Agreement. Each Party shall retain such records for at least [           ] years
after the termination of this Agreement.

         8.2 Inspection.  Each Party shall permit the other Party, at such other
Party's  expense,  to examine its books of account and records  which  relate to
this Agreement to the extent  necessary to ensure such Party's  compliance  with
the terms of this  Agreement;  provided,  however,  that neither  Party shall be
obligated  pursuant  to this  Section 8.2 to provide  access to any  information
which it  reasonably  considers  to be a trade  secret or  similar  confidential
information  except under appropriate  confidentiality  agreements.  The Parties
shall  reconcile  any  underpayment  or  overpayment  within [            ] days
after the  accountant  delivers the results of the audit.  In the event that any
inspection performed  under this Section  reveals an  underpayment  in excess of
[               ] in any Royalty Period, the Party obligated to make the payment
shall bear the full cost of such audit.

9.       PROPRIETARY MATERIALS.

         9.1 Ownership of Proprietary  Materials.  In the course of the Research
Program,  one Party  (the  "Provider")  may  transfer  to the other  Party  (the
"Recipient") certain of its Proprietary  Materials.  The Recipient  acknowledges
and  agrees  that  such  Proprietary  Materials  are and  shall  be owned by the
Provider. The Recipient agrees to execute and deliver any


                                       12.

<PAGE>

documents of assignment or conveyance to effectuate the ownership  rights of the
Provider in such Proprietary Materials.

         9.2  Use  of  Proprietary  Materials.   The  Recipient  agrees  to  use
Proprietary  Materials provided by the Provider solely for purposes set forth in
this  Agreement.  The Recipient  shall use such  Proprietary  Materials  only in
compliance with all applicable Federal, state, and local laws and regulations.

         9.3  Transfer  of  Proprietary  Materials.   The  Recipient  shall  not
distribute any Proprietary Materials to any third party other than its employees
who are working on the Research Program.

         9.4 Disposition of Unused Proprietary Materials. Upon completion of the
Research Program, or sooner at the request of the Provider,  the Recipient shall
either destroy or return to the Provider any unused Proprietary Materials.

10.      CONFIDENTIAL INFORMATION.

         10.1     Confidential Information.

                  (a) Restrictions on Confidential Information.  With respect to
all Confidential  Information furnished by one Party (the "Disclosing Party") to
the  other  (the  "Receiving  Party")  during  the term of this  Agreement,  the
Receiving Party shall:

                           (i)      maintain  such  Confidential  Information in
                                    strict confidence;

                           (ii)     not  disclose  or permit the  disclosure  of
                                    such Confidential Information to any persons
                                    other  than  to  its  directors,   officers,
                                    consultants  and  employees who need to know
                                    such  Confidential  Information  in order to
                                    conduct  the  Research  Program  and who are
                                    obligated  to  maintain   the   confidential
                                    nature of such Confidential Information;

                           (iii)    use such  Confidential  Information only for
                                    the  purposes  set  forth in this  Agreement
                                    herein  and not for its own  benefit  or for
                                    the benefit of any other  person or business
                                    entity; and

                           (iv)     allow its  directors,  officers,  employees,
                                    agents,   and   other   representatives   to
                                    reproduce the Confidential  Information only
                                    to  the  extent   necessary  to  effect  the
                                    purposes set forth in this  Agreement,  with
                                    all  such  reproductions   being  considered
                                    Confidential Information.


                                       13.

<PAGE>

                  (b)  Exceptions  to  Restrictions.   The  obligations  of  the
Receiving  Party under  Subsection  (a) above shall not apply to the extent that
the Receiving Party can demonstrate that certain Confidential Information:

                           (i)      was in the public domain prior  to  the time
                                    of its disclosure;

                           (ii)     entered the public  domain after the time of
                                    its  disclosure  through means other than an
                                    unauthorized  disclosure  resulting  from an
                                    act or omission by the Receiving Party;

                           (iii)    was independently developed or discovered by
                                    the Receiving Party at any time prior to the
                                    time of its disclosure under this Agreement,
                                    as shown by prior documentary evidence;

                           (iv)     is or was disclosed to the  Receiving  Party
                                    at any time,  whether  prior to or after the
                                    time of its disclosure under this Agreement,
                                    by  a  third  Party   having  no   fiduciary
                                    relationship  with the Disclosing  Party and
                                    having no obligation of confidentiality with
                                    respect to such Confidential Information; or

                           (v)      is required to be  disclosed  to comply with
                                    applicable  laws  or  regulations  or with a
                                    court or administrative order, provided that
                                    the Disclosing  Party receives prior written
                                    notice  of  such  disclosure  and  that  the
                                    Receiving  Party  takes all  reasonable  and
                                    lawful   actions   to  obtain   confidential
                                    treatment  for  such   disclosure   and,  if
                                    possible,  to  minimize  the  extent of such
                                    disclosure.

                  (c) Ownership of Confidential Information. The Receiving Party
agrees  that  the  Disclosing  Party  (or any  third  party  entrusting  its own
Confidential  Information  to the  Disclosing  Party)  is and shall  remain  the
exclusive  owner of the  Confidential  Information  disclosed by the  Disclosing
Party and all patent, copyright, trademark, trade secret, and other intellectual
property  rights in such  Confidential  Information  or  arising  therefrom.  No
option,  license, or conveyance of such rights to the Receiving Party is granted
except as expressly set forth in this Agreement.

                  (d) Return of Confidential  Information.  Upon the termination
of this  Agreement,  or at any time upon the written  request of the  Disclosing
Party,  the Receiving Party shall return to the Disclosing  Party all originals,
copies, and summaries of documents, materials, and other tangible manifestations
of Confidential Information in the possession or control of the Receiving Party,
except  that  the  Receiving  Party  may  retain  one  copy of the  Confidential
Information  in the  possession  of its legal counsel (for ArQule) and its Legal
and Trademarks  Department  (for Sugen) solely for the purpose of monitoring its
obligations under this Agreement.


                                       14.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

11.      TERM AND TERMINATION.

         11.1 Term.  This  Agreement  shall  commence on the Effective  Date and
shall continue for a period of one (1) year unless earlier  terminated  pursuant
to this Section 11;  provided,  however,  that upon the mutual  agreement of the
Parties,  the term of this Agreement may be extended for additional one (1) year
periods.

         11.2 Termination for Breach. This Agreement may be terminated by either
Party by reason of a material  breach that the  breaching  Party fails to remedy
within [     ] days after written notice thereof by the non-breaching Party.

         11.3  Force  Majeure.  Neither  Party  will be  responsible  for delays
resulting  from  acts  beyond  the  control  of such  Party,  provided  that the
nonperforming Party uses commercially reasonable efforts to avoid or remove such
causes of  nonperformance  and continues  performance  hereunder with reasonable
dispatch whenever such causes are removed.

         11.4  Effect  of  Termination.   Notwithstanding   the  termination  or
expiration of this Agreement, this Agreement shall remain in effect: (a) for any
Active  Sugen  Compound for the period of time as is necessary to allow Sugen to
determine if such Active Sugen  Compound is a Licensed  Compound and (b) for any
such Licensed Compound or for any other Licensed Compound for the period of time
as is necessary to complete  Preclinical  Development and  commercialization  of
such Licensed  Compound.  Upon the termination of this Agreement,  ArQule agrees
that it shall not  initiate  any  programs  for any other  party  involving  the
production of Directed  Arrays based upon any Sugen Compound,  Sugen  Derivative
Compound,  Active Sugen Compound or Active Homolog  thereto.  ArQule agrees that
any breach of this  clause may be  remedied  by an  injunction  against any such
program, among other remedies.

         11.5 Survival of  Provisions.  The following  provisions  shall survive
termination or expiration of this Agreement: Sections 3, 5, 6, 7, 8, 9, 10, 11.4
and 12.

12.      MISCELLANEOUS.

         12.1  Publicity.  No  press  release,  advertising,  promotional  sales
literature,  or other  promotional  oral or written  statements to the public in
connection  with or  alluding  to work  performed  under this  Agreement  or the
relationship  between  the  Parties  created  by it,  having or  containing  any
reference to ArQule or Sugen,  shall be made by either  Party  without the prior
written approval of the other Party.

         12.2 Relationship of Parties. For the purposes of this Agreement,  each
Party is an  independent  contractor  and not an agent or  employee of the other
Party.   Neither   Party   shall  have   authority   to  make  any   statements,
representations or commitments of any kind, or to take any action which shall be
binding on the other Party,  except as may be explicitly  provided for herein or
authorized in writing.



                                       15.

<PAGE>

         12.3  Dispute  Resolution.  Any  disputes  arising  between the Parties
relating to,  arising out of or in any way connected  with this Agreement or any
term or condition  hereof, or the performance by either Party of its obligations
hereunder,  whether  before or after  termination  of this  Agreement,  shall be
promptly  presented to the Chief Executive  Officers of each of ArQule and Sugen
for resolution and if the Chief  Executive  Officers or their  designees  cannot
promptly  resolve such disputes,  then such dispute shall be finally resolved by
binding  arbitration.  Whenever a Party shall  decide to  institute  arbitration
proceedings, it shall give written notice to that effect to the other Party. The
Party  giving  such  notice  shall  refrain  from  instituting  the  arbitration
proceedings  for a  period  of  sixty  (60)  days  following  such  notice.  Any
arbitration  hereunder  shall be  conducted  under the  commercial  rules of the
American Arbitration Association.  Each such arbitration shall be conducted by a
panel of three  arbitrators  appointed in accordance with such rules;  provided,
however,  that both  Parties  hereto  shall be  entitled  to  representation  by
counsel,  to appear and present  written and oral  evidence  and argument and to
cross-examine  witnesses  presented by the other Party.  The arbitral  panel (i)
shall  have the  authority  to grant  specific  performance,  (ii) may  allocate
between the Parties the costs of arbitration  in such  equitable  manner as they
may  determine,  but (iii)  shall not render an arbitral  award  contrary to the
provisions  of this  Agreement.  The arbitral  award shall be in writing and the
arbitral  panel shall provide  written  reasons for its award.  The award of the
arbitral  panel shall be final and binding  upon the  Parties  hereto.  Any such
arbitration shall be held in Boston, Massachusetts, or any other mutually agreed
location. Judgment upon the award so rendered may be entered in any court having
jurisdiction or application may be made to such court for judicial acceptance of
any award and an order of enforcement, as the case may be.

         12.4  Counterparts.  This  Agreement  may be  executed  in one or  more
counterparts,  each of  which  shall be  deemed  an  original,  and all of which
together shall be deemed to be one and the same instrument.

         12.5 Headings.  All headings in this Agreement are for convenience only
and shall not affect the meaning of any provision hereof.

         12.6 Binding  Effect.  This Agreement shall inure to the benefit of and
be binding upon the Parties and their respective lawful successors and assigns.

         12.7  Assignment.  This  Agreement  may not be assigned by either Party
without the prior written consent of the other Party,  except that either of the
Parties may assign this Agreement to a successor in connection  with the merger,
consolidation, or sale of all or substantially all of its assets or that portion
of its business pertaining to the subject matter of this Agreement.

         12.8 Notices. All notices,  requests,  demands and other communications
required or permitted to be given pursuant to this Agreement shall be in writing
and  shall be  deemed  to have  been  duly  given  upon the date of  receipt  if
delivered by hand,  recognized  national overnight courier,  confirmed facsimile
transmission, or registered or certified mail, return receipt requested, postage
prepaid, to the following addresses or facsimile numbers:


                                       16.

<PAGE>

         If to ArQule:

                                    ArQule, Inc.
                                    200 Boston Avenue
                                    Medford, MA  02155
                                    Attn:  Eric B. Gordon
                                    Tel: (617) 395-4100
                                    Fax: (617) 395-1225

         with a copy (which shall not constitute notice) to:

                                    Palmer & Dodge
                                    One Beacon Street
                                    Boston, MA  02108
                                    Attn:  Michael Lytton, Esq.
                                    Tel: (617) 573-0327
                                    Fax: (617) 227-4420

         If to Sugen:

                                    Sugen, Inc.
                                    515 Galveston Drive
                                    Redwood City, CA 94063-4720
                                    Attn:   Stephen Evans-Freke
                                    Tel: (415) 306-7700
                                    Fax: (415) 369-0741

Either Party may change its designated address and facsimile number by notice to
the other Party in the manner provided in this Section 12.8.

         12.9 Amendment and Waiver. This Agreement may be amended, supplemented,
or  otherwise  modified at any time,  but only by means of a written  instrument
signed by both Parties. Any waiver of any rights or failure to act in a specific
instance  shall  relate only to such  instance  and shall not be construed as an
agreement to waive any rights or fail to act in any other  instance,  whether or
not similar.

         12.10  Governing Law. This Agreement and the legal  relations among the
Parties shall be governed by and  construed in  accordance  with the laws of the
Commonwealth of Massachusetts irrespective of any conflict of laws principles.

         12.11  Severability.  In the event that any provision of this Agreement
shall,  for any reason,  be held to be invalid or  unenforceable in any respect,
such invalidity or unenforceability shall not affect any other provision hereof,
and this  Agreement  shall be  construed  as if such  invalid  or  unenforceable
provision had not been included herein.


                                       17.

<PAGE>

         12.12 Entire Agreement. This Agreement constitutes the entire agreement
between the Parties with respect to the subject matter hereof and supersedes any
and  all  prior  or  contemporaneous  oral  and  prior  written  agreements  and
understandings.

         12.13  Indemnification.  To the maximum  extent  permitted  by law each
Party shall  indemnify  and hold  harmless  the other Party from and against all
claims,  expenses or liability of whatever nature arising from any default, act,
omission or negligence of the Indemnifying  Party, or the  Indemnifying  Party's
agents or  employees  or  others  exercising  rights  by,  through  or under the
Indemnifying  Party, or the failure of the Indemnifying Party or such persons to
comply with any  applicable  laws,  rules,  regulations,  codes,  ordinances  or
directives of governmental authorities,  in each case to the extent the same are
related,  directly or indirectly,  to this Agreement and/or the Research Program
described  herein;  provided,  however,  that in no event shall the Indemnifying
Party be obligated under this section to indemnify the  Indemnified  Party where
such  claim,  expense or  liability  results  solely from any  omission,  fault,
negligence or other misconduct of the Indemnified Party.

         IN WITNESS  WHEREOF,  the undersigned  have duly executed and delivered
this  Agreement  as a sealed  instrument  effective  as of the date first  above
written.


                                   ARQULE, INC.


                                   By:      /s/ Eric B. Gordon
                                      ------------------------------------------
                                   Name:    Eric B. Gordon
                                   Title:   President


                                   SUGEN, INC.


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


                                       18.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED




                                    EXHIBIT A

                                  RESEARCH PLAN

                            ARQULE/SUGEN PROJECT PLAN
[













                                                                               ]


<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


Arqule/SUGEN Project Plan
- --------------------------------------------------------------------------------

[











                                                                              ]


                                       2.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


                                    EXHIBIT B

                              DESCRIPTION OF FIELD

         The Field shall mean, with respect to any Target, the field of [
                                                         ]  Such Field includes
[

                                      ]




<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


                                    EXHIBIT C

                           LICENSED COMPOUND CRITERIA

Compounds will evaluated as Licensed  Compound  candidates based good scientific
and business criteria, including one or more of the following:

o         Compound potency as measured by [
                      ]

o         Compound selectivity as calculated by [
                                                                        ]

o         Assessment of effects on [
                                                ]

o         Assessment of effects on [                                           ]

o         Assessment of [                                                      ]

o         Assessment of effects on [                                       ]

o         Assessment of effects on [                   ] in appropriate species

o         Assessment of [                  ]



<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


                                    EXHIBIT D

                                 SUGEN COMPOUNDS

                                                         [












                                                                               ]



                                       1.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED



[














                                                                              ]




                                       2.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[




















                                                                               ]




                                       3.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED
[
















                                                                               ]



                                       4.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED
[


















                                                                               ]



                                       5.

<PAGE>
                                                CONFIDENTIAL TREATMENT REQUESTED

[




















                                                                               ]



                                       6.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[




















                                                                               ]




                                       7.

<PAGE>
                                                CONFIDENTIAL TREATMENT REQUESTED

[

















                                                                               ]



                                       8.

<PAGE>
                                                CONFIDENTIAL TREATMENT REQUESTED


[



















                                                                               ]




                                       9.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[




























                                                                               ]



                                       10.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[



























                                                                             ]



                                       11.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED
[






























                                                                               ]



                                       12.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[





















                                                                              ]




                                       13.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED
[








                                                                       ]






                                       14.




                                                                   EXHIBIT 10.55
[SUGEN LETTERHEAD]
                                   May 2, 1996



MAX-PLANCK INSTITUT fuer physiologische und
klinische Forschung W. G. Kerckhoff
Institut Abteilung Molekulare Zellbiologie
Parkstrasse 1,
61231 Bad Nauheim GERMANY

MAX-PLANCK-GESELLSCHAFT zur Forderung
der Wissenschaften e.V.
Residenzstrasse 1a, W-8000
Muenchen 2

Garching Innovation GmbH
Koeniginstrasse 19
80539 Muechen

Gentlemen:

         We refer to the Research and License  Agreement  into which our company
entered  with  yourselves  on October  1, 1993.  The  Agreement  provided  for a
"Research  Period" (as so defined) of three years  commencing  on the  Effective
Date,  which  Period is due to expire as of October 1, 1996.  We propose by this
Letter  Agreement that all the parties  commit to a three-year  extension of the
Research Period,  thereby providing for SUGEN's research funding obligations and
the performance obligations of all parties to be extended until October 1, 1999.
All other  provisions of the Agreement  between us will remain in full force and
effect,  with the sole modification  that the "MPI Research Project"  definition
shall be extended to include  investigations into the field of neurite outgrowth
promotion as well as the other fields  already  cited,  all  restricted  to such
investigations as are under the leadership of Prof. Dr. Werner Risau.

         If you are in agreement  with the above,  please so indicate by signing
both copies of this Letter  Agreement,  returning  one to us and  retaining  the
other for your own files.

                                        Sincerely,

                                        SUGEN, Inc.



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



<PAGE>


2 May 1996
Page 2




Acknowledged and Agreed to:

                                    MAX-PLANCK INSTITUT fuer physiologische und
                                    klinische Forschung W. G. Kerckhoff Institut
                                    Abteilung Molekulare Zellbiologie


                                        By:       /s/ Werner Rissau
                                           -------------------------------------
                                             Name:    Prof. Dr. Werner Rissau
                                             Title:   Direktor am Institute


MAX-PLANCK-GESELLSCHAFT zur Forderung der Wissenschaften e.V.


                                        By:       /s/ Heinrich Kuhn
                                           -------------------------------------
                                             Name:    Dr. Heinrich Kuhn         
                                             Title:   Leiter des Patentreferates


GARCHING INNOVATION GmbH


                                        By:       /s/ Heinrich Kuhn
                                           -------------------------------------
                                             Name:    Dr. Heinrich Kuhn         
                                             Title:   Geschaftsfuhrer








                                                                   EXHIBIT 10.56




                                 PROMISSORY NOTE



$1,107,228.03                                           Redwood City, California
                                                        August 29, 1996


         FOR VALUE RECEIVED,  the undersigned hereby executes this full recourse
promissory note (the "Note") and unconditionally promises to pay to the order of
SUGEN,  INC., a Delaware  corporation  (the  "Company"),  or its  successors  or
assigns,  at 515 Galveston  Drive,  Redwood City,  California,  or at such other
place as the holder  hereof may  designate  in writing,  in lawful  money of the
United States of America and in immediately  available  funds, the principal sum
of one million, one hundred seven thousand, two hundred twenty eight dollars and
three cents  ($1,107,228.03)  (of which two hundred  twenty  four  thousand  one
hundred seventy eight dollars and thirty six cents  ($224,178.36)  shall consist
of a loan for the purpose of the payment of tax withholding  associated with the
August 29, 1996 stock option  exercise)  together with interest accrued from the
date hereof on the unpaid  principal at the rate of 6.84% per annum,  compounded
annually,  or the maximum rate  permissible  by law (which under the laws of the
State of California shall be deemed to be the laws relating to permissible rates
of interest on commercial loans), whichever is less, as follows:

                  Principal   Repayment.   The  outstanding   principal   amount
         hereunder  shall be due and  payable  in full on August  29,  2001 (the
         "Principal Repayment Date").

                  Interest Payments. Interest shall be payable in arrears on the
         Principal  Repayment  Date and  shall be  calculated  on the basis of a
         365-day year for the actual number of days elapsed;

         provided,  however, that in the event that the undersigned's continuous
         status as an  employee,  director  or  consultant  with the  Company is
         terminated  for any reason prior to payment in full of this Note,  this
         Note  shall be  accelerated  and all  remaining  unpaid  principal  and
         interest  shall  become  due and  payable on the  ninetieth  (90th) day
         following such termination;  provided,  further, that in the event that
         the undersigned requests the release of any percentage of the shares of
         the Common Stock from the Stock Pledge Agreement (of even date herewith
         between  the  undersigned  and  the  Company)  prior  to the  Principal
         Repayment  Date,  the same  percentage  of the  principal  of the Note,
         together  with all accrued  interest then  outstanding  under the Note,
         shall become due immediately prior to the release of such percentage of
         shares from the Pledge Agreement.

         If the  undersigned  fails  to pay  any of the  principal  and  accrued
interest  when due,  the Company,  at its sole  option,  shall have the right to
accelerate  this Note,  in which  event the  entire  principal  balance  and all
accrued  interest  shall become  immediately  due and payable,  and  immediately
collectible by the Company pursuant to applicable law.



<PAGE>

         This Note may be prepaid at any time  without  penalty.  All money paid
toward the  satisfaction  of this Note shall be applied  first to the payment of
interest as required hereunder and then to the retirement of the principal.

         The full amount of this Note is secured by a pledge of shares of Common
Stock of the Company,  and is subject to all of the terms and  provisions of the
related Stock Pledge Agreement.

         The undersigned hereby represents and agrees that the amounts due under
this Note are not consumer  debt,  and are not incurred  primarily for personal,
family or household purposes, but are for business and commercial purposes only.

         The  undersigned  hereby  waives  presentment,  protest  and  notice of
protest, demand for payment, notice of dishonor and all other notices or demands
in connection with the delivery, acceptance, performance, default or endorsement
of this Note.

         The holder  hereof  shall be entitled to recover,  and the  undersigned
agrees to pay when incurred,  all costs and expenses of collection of this Note,
including without limitation, reasonable attorneys' fees.

         This Note shall be governed by, and construed, enforced and interpreted
in accordance with, the laws of the State of California,  excluding  conflict of
laws  principles  that  would  cause  the  application  of  laws  of  any  other
jurisdiction.



                                       Signed      /s/ Stephen Evans-Freke
                                             -----------------------------------
                                                       Stephen Evans-Freke






                                                                   EXHIBIT 10.57




                                    AGREEMENT

                       for the purchase of Common Stock of

                                   SUGEN, INC.

                                       by

                           VISION PHARMACEUTICALS L.P.




<PAGE>



                                TABLE OF CONTENTS
                                                                            Page

1.  Purchase and Sale of Common Stock........................................ 1.
    1.1      Initial Issuance of Common Stock................................ 1.
    1.2      Subsequent Issuance of Common Stock............................. 1.

2.  Closing; Delivery........................................................ 2.
    2.1      Closing......................................................... 2.
    2.2      Payment and Delivery............................................ 4.

3.  Representations, Warranties and Covenants of the Company................. 4.
    3.1      Organization.................................................... 4.
    3.2      Capitalization.................................................. 4.
    3.3      Authority....................................................... 5.
    3.4      Financial Statements............................................ 5.
    3.5      Issuance of the Shares.......................................... 5.
    3.6      No Conflict with Law or Documents............................... 5.
    3.7      Absence of Certain Developments................................. 5.
    3.8      Litigation...................................................... 6.
    3.9      Registration Rights Covenant.................................... 6.
    3.10     Covenant to Keep Public Information Available...................12.
    3.11     SEC Reports.....................................................12.
    3.12     Securities Law Compliance.......................................12.
    3.13     Registration Rights.............................................12.

4.  Representations, Warranties and Covenants of Purchaser...................12.
    4.1      Legal Power.....................................................12.
    4.2      Due Execution...................................................13.
    4.3      Investment Representations and Covenants........................13.
    4.4      Standstill Covenant.............................................14.
    4.5      Lockup Covenant.................................................14.
    4.6      Right of First Offer............................................15.

5.  Miscellaneous............................................................17.
    5.1      Governing Law...................................................17.
    5.2      Successors and Assigns..........................................17.
    5.3      Entire Agreement................................................17.
    5.4      Separability....................................................17.
    5.5      Amendment and Waiver............................................17.
    5.6      Notices.........................................................17.
    5.7      Fees and Expenses...............................................18.
    5.8      Titles and Subtitles............................................18.
    5.9      Counterparts....................................................18.
    5.10     Consent to Jurisdiction and Venue...............................18.
    5.11     Guarantee.......................................................18.



                                       i.


<PAGE>


                         COMMON STOCK PURCHASE AGREEMENT


         THIS COMMON STOCK  PURCHASE  AGREEMENT  (the  "Agreement) is made as of
September 30, 1996 (the "Effective Date") by and between SUGEN, INC., a Delaware
corporation (the "Company"),  and VISION  PHARMACEUTICALS  L.P., a Texas limited
partnership  ("Purchaser"),  and, for  purposes of Section 5.11 only,  ALLERGAN,
INC.,  a  Delaware  corporation  ("Allergan").  In  consideration  of the mutual
promises,   representations,   warranties  and  conditions  set  forth  in  this
Agreement, the Company and Purchaser agree as follows:

1.       PURCHASE AND SALE OF COMMON STOCK.

         1.1      Initial Issuance of Common Stock.

                  (a) The  Company  has  authorized  the  issuance  and  sale to
Purchaser of up to 191,571 shares (the  "Shares") of its common stock,  $.01 par
value (the "Common Stock").

                  (b)  In  reliance   upon   Purchaser's   representations   and
warranties contained in Section 4 hereof and subject to the terms and conditions
set forth  herein,  the Company  agrees to sell to Purchaser  the Shares,  to be
issued and sold at a price per share equal to $20.88.

                  (c) In reliance upon the representations and warranties of the
Company  contained  in Section 3 hereof and subject to the terms and  conditions
set forth  herein,  Purchaser  hereby  agrees to purchase  the Shares at the per
share purchase price set forth above.

         1.2      Subsequent Issuance of Common Stock.

                  (a) The Company agrees to use all reasonable  efforts to offer
or, if applicable,  to arrange for its  underwriters to offer,  Purchaser or its
designated  affiliate the  opportunity to purchase in the Company's next private
offering of equity  securities of the Company to institutional  investors and/or
individuals (other than a sale of equity securities of the Company in connection
with a scientific or commercial collaboration or intellectual property licensing
agreement) or directed public  offering or  underwritten  public offering of the
Company's Common Stock pursuant to an effective registration statement under the
Securities Act of 1933, as amended (the "Securities  Act"), on the same terms as
others  purchasing  in such  offering,  the number of shares of Common  Stock or
other equity securities of the Company (the "Additional Shares") representing an
aggregate investment of $3.0 million. Purchaser hereby confirms its intention to
purchase the Additional Shares in the Company's next offering,  provided (i) the
closing  date,  or  effective  date if such  offering  is  registered  under the
Securities Act, of such offering takes place within two (2) years of the date of
this Agreement;  (ii) such offering  results in gross proceeds to the Company of
at least $10.0 million; (iii) the purchase of such shares by Purchaser would not
result in  beneficial  ownership  by  Purchaser of greater than 9.9% of the then
outstanding  Common  Stock  of  the  Company;   (iv)  if  such  offering  is  an
underwritten  public  offering of Common  Stock,  Purchaser  shall not  purchase
Common Stock at a price per share



                                       1.

<PAGE>

more than 3.0% greater than the closing  price of the Common Stock on the day of
the  pricing of such  offering  or the day prior to the  pricing if the  pricing
occurs prior to the opening of the Nasdaq National Market on the day of pricing;
and (v) if such offering is not an underwritten  public offering of Common Stock
(A) Purchaser  shall not purchase Common Stock at a price per share greater than
the closing price of the Common Stock on the day of the pricing of such offering
or the day prior to the  pricing if the pricing  occurs  prior to the opening of
the Nasdaq  National  Market on the day of pricing and (B) if the Company's next
offering  consists of a private offering of preferred  stock,  within sixty days
following the closing of such preferred stock offering, Purchaser shall have the
option to purchase  Common Stock at a price per share equal to the closing price
of the Common Stock on the day of the pricing of such  offering or the day prior
to the pricing if the pricing occurs prior to the opening of the Nasdaq National
Market on the day of pricing in lieu of purchasing  the preferred  stock offered
in the private  offering.  However,  Purchaser  shall be under no  obligation to
purchase any or all of such securities.

                  (b)   Notwithstanding   anything  in  this  Agreement  to  the
contrary,  in the event the Additional Shares are made available to Purchaser in
accordance with the terms of this Agreement and Purchaser fails to purchase,  or
make a bona fide offer to purchase,  such securities (provided the provisions of
Section 1.2(a) are complied with), the Company shall have the right for a period
of 90 days from the closing date,  or if such  offering is registered  under the
Securities   Act,  the  effective   date,  of  its  offering  to  terminate  the
Collaboration Agreement by giving Purchaser 10 days written notice. In the event
the Company exercises its termination option pursuant to this Section 1.2(b), it
shall retain the payments  made under the  Collaboration  Agreement  between the
Company and Purchaser dated as of the date of this Agreement (the "Collaboration
Agreement").

2.       CLOSING; DELIVERY.

         2.1  Closing.  The closing of the sale of purchase of Shares under this
Agreement  (the"Closing")  shall  take  place  at  5:00  p.m.  on  the  date  of
satisfaction  of the  conditions  set forth below (the "Closing  Date"),  at the
offices of Cooley Godward LLP, Five Palo Alto Square,  3000 El Camino Real, Palo
Alto,  California,  or at such other time and place as the Company and Purchaser
may agree.  At the Closing,  the Company will issue and sell, and Purchaser will
purchase, the Shares for an aggregate purchase price of $4,000,002.48.

                  (a) The obligations of Purchaser to purchase the Shares at the
Closing are subject to the  fulfillment on or before the Closing Date of each of
the  following  conditions,  which may be waived only in  writing,  on or before
October 4, 1996:

                           (i) The representations and warranties of the Company
contained in Section 3 shall be true and correct in all material respects on and
as of the Closing Date with the same force and effect as if such representations
and warranties had been made on and as of the Closing Date.




                                       2.

<PAGE>

                           (ii) The Company  shall have  performed  and complied
with all agreements, obligations and conditions contained in this Agreement that
are  required to be  performed  or complied  with by it on or before the Closing
Date.

                           (iii) All authorizations,  approvals,  or permits, if
any, of any governmental authority or regulatory body of the United States or of
any state that are required in  connection  with the lawful sale and issuance of
the Shares at the Closing  pursuant to this  Agreement  shall have been obtained
and shall be  effective  on and as of the Closing  Date.  No stop order or other
order enjoining the sale of the Shares shall have been issued and no proceedings
for  such  purpose  shall  be  pending  or,  to the  knowledge  of the  Company,
threatened by the SEC, or any commissioner of corporations or similar officer of
any state having jurisdiction over this transaction. At the time of the Closing,
the sale and issuance of the Shares  shall be legally  permitted by all laws and
regulations to which Purchaser and the Company are subject.

                           (iv) The parties shall have executed and delivered to
each other the Collaboration Agreement dated as of the Closing Date.

                           (v) Purchaser shall have received from Cooley Godward
LLP,  counsel for the Company,  an opinion dated as of the Closing Date covering
the matters set forth in Exhibit A.

                           (vi)  Purchaser  shall have  received  a  certificate
representing the Shares, duly registered in Purchaser's name.

                  (b) The  obligations of the Company are subject to fulfillment
on or before the Closing Date of each of the following conditions,  which may be
waived only in writing, on or before October 4, 1996:

                           (i)  The   representations   and  warranties  of  the
Purchaser  contained  in  Section 4 shall be true and  correct  in all  material
respects on and as of the Closing Date with the same force and effect as if such
representations and warranties had been made on and as of the Closing Date.

                           (ii) The Purchaser  shall have performed and complied
with all agreements, obligations and conditions contained in this Agreement that
are  required to be  performed  or complied  with by it on or before the Closing
Date.

                           (iii) All authorizations,  approvals,  or permits, if
any, of any governmental authority or regulatory body of the United States or of
any state that are required in  connection  with the lawful sale and issuance of
the Shares at the Closing  pursuant to this  Agreement  shall have been obtained
and shall be  effective  on and as of the Closing  Date.  No stop order or other
order enjoining the sale of the Shares shall have been issued and no proceedings
for  such  purpose  shall  be  pending  or,  to the  knowledge  of the  Company,
threatened



                                       3.

<PAGE>

by the SEC, or any  commissioner of corporations or similar officer of any state
having jurisdiction over this transaction.  At the time of the Closing, the sale
and  issuance  of  the  Shares  shall  be  legally  permitted  by all  laws  and
regulations to which Purchaser and the Company are subject.

                           (iv) The parties shall have executed and delivered to
each other the Collaboration Agreement dated as of the Closing Date.

                           (v)  Purchaser  shall have  delivered an aggregate of
$4,000,002.48 to the Company.

         2.2  Payment and  Delivery.  At the  Closing,  subject to the terms and
conditions  hereof, the Company will deliver to Purchaser an opinion from Cooley
Godward LLP, counsel to the Company, covering the matters set forth in Exhibit A
attached  hereto and a stock  certificate,  registered in the name of Purchaser,
representing the Shares to be purchased by Purchaser from the Company,  dated as
of the Closing, against payment of the purchase price therefor by wire transfer,
unless other means of payment  shall have been agreed upon by Purchaser  and the
Company.

3.       REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.

         Subject  to and except as  disclosed  by the  Company in the  Company's
Annual  Report on Form 10-K for the fiscal  year ended  December  31,  1995 (the
"Form 10-K"),  quarterly  reports on Form 10-Q for the quarters  ended March 31,
1996 and June 30,  1996 (the  "Form  10-Qs")  and Proxy  Statement  for the 1996
Annual  Meeting  of  Stockholders,  dated  as  of  April  5,  1996  (the  "Proxy
Statement"),  each  previously  delivered  to  Purchaser,  or in the Schedule of
Exceptions  attached  hereto as Exhibit B (the  "Schedule of  Exceptions"),  the
Company  hereby  represents  and warrants to Purchaser as follows as of the date
hereof and as of the Closing Date, and all such  representations  and warranties
shall survive the Closing:

         3.1  Organization.  The Company is a  corporation,  duly  incorporated,
validly  existing and in good standing under the laws of the jurisdiction of its
incorporation. The Company has all requisite power and authority to own or lease
its properties  and to conduct its business as now conducted.  The Company holds
all  licenses  and  permits  required  for the  conduct of its  business  as now
conducted,  which, if not obtained,  would have a material adverse effect on the
business, financial condition or results of operations of the Company taken as a
whole. The Company is qualified as a foreign corporation and is in good standing
in all states where the conduct of its  business or its  ownership or leasing of
property  requires  such  qualification,  except where the failure to so qualify
would not have a material adverse effect on the business, financial condition or
results of operations of the Company taken as a whole.

         3.2  Capitalization.  The authorized,  issued and  outstanding  capital
stock of the Company and a description  of the Company's  stock option and stock
purchase  plans is as set forth in the Proxy  Statement.  All of the  issued and
outstanding shares of common stock have


                                       4.

<PAGE>

been duly  authorized,  validly  issued  and are fully  paid and  nonassessable.
Except for rights  granted  under the  Company's  1992 Stock Option  Plan,  1994
Non-Employee  Directors'  Stock  Option  Plan,  Employee  Stock  Purchase  Plan,
Long-Term Objectives Stock Option Plan for Senior Management and Preferred Share
Purchase  Rights Plan and the  outstanding  warrants  described in the Form 10-K
(certain of which have been exercised as described in Schedule  3.2),  there are
no existing subscriptions,  options,  warrants, calls, commitments,  agreements,
conversion  or other  rights  of any  character  (contingent  or  otherwise)  to
purchase  or  otherwise  acquire  from the  Company,  at any  time,  or upon the
happening of any stated  event,  any shares of the capital stock of the Company.
On September 27, 1996,  10,685,896  shares of the Common Stock were outstanding,
and no other shares of Company stock were outstanding.

         3.3  Authority.  The Company has all  requisite  power and authority to
enter into this  Agreement,  and to  consummate  the  transactions  contemplated
hereby. The execution and delivery of this Agreement and the consummation of the
transactions  contemplated  hereby have been duly  authorized  by all  necessary
corporate action on the part of the Company,  and upon execution and delivery by
the Company,  this Agreement will  constitute a valid and binding  obligation of
the  Company,  enforceable  against  the Company in  accordance  with its terms,
subject to applicable  bankruptcy,  insolvency,  reorganization,  moratorium and
similar  laws  relating to or affecting  creditor's  rights from time to time in
effect, and subject to general equity principles.

         3.4  Financial  Statements.  The  financial  statements  of the Company
included  in the Form  10-K and Form  10-Qs  fairly  presented  in all  material
respects  the  financial  position and results of  operations  of the Company at
their respective  dates and for the respective  periods to which they apply; and
such  financial  statements  have been  prepared in  accordance  with  generally
accepted  accounting  principles  consistently  applied  throughout  the periods
involved except as otherwise stated therein.

         3.5  Issuance of the Shares.  The Shares,  when issued  pursuant to the
terms of this Agreement,  will be duly and validly authorized and issued,  fully
paid and nonassessable.

         3.6 No Conflict  with Law or  Documents.  The  execution,  delivery and
consummation of this Agreement and the transactions contemplated hereby will not
(a) conflict with any  provisions of the  Certificate  of  Incorporation  or the
Bylaws of the  Company;  (b) result in any  violation of or default or loss of a
benefit under, or permit the  acceleration  of any obligation  under or conflict
with (in each case, upon the giving of notice, the passage of time, or both) any
mortgage,  indenture,  lease, agreement or other instrument,  permit,  franchise
license,  judgment, order, decree, law, ordinance, rule or regulation applicable
to the Company or its respective properties.

         3.7 Absence of Certain  Developments.  Since June 30, 1996, the Company
has not (a) incurred or become subject to any material liabilities  (absolute or
contingent) except current liabilities incurred, and liabilities under contracts
entered  into,  in  the  ordinary  course  of  business,  consistent  with  past
practices; (b) mortgaged, pledged or subjected to lien, charge or



                                       5.

<PAGE>

any other encumbrance any material assets,  tangible or intangible except in the
ordinary course of business,  consistent with past practices; (c) sold, assigned
or transferred any material assets or canceled any material debts or obligations
except in the ordinary course of business,  consistent with past practices;  (d)
suffered any extraordinary  losses,  or waived any rights of substantial  value;
(e) entered into any material  transaction  other than in the ordinary course of
business, consistent with past practices; or (f) otherwise had any change in its
condition,  financial or otherwise, except for changes in the ordinary course of
business,  consistent with past practices,  none of which individually or in the
aggregate has been materially adverse to the Company.

         3.8  Litigation.  To the  Company's  knowledge,  there are no  actions,
suits,  proceedings or investigations pending or threatened against or affecting
the Company that in the aggregate  could  reasonably be anticipated to result in
any material adverse effect on the Company.

         3.9      Registration Rights Covenant.

                  (a)  At  any  time  during  the  180-day  period   immediately
following  the earlier of (i) the  expiration  of the initial  Research Term (as
defined in the Collaboration  Agreement) without giving effect to any extensions
thereof or (ii) the earlier termination of the Research Term pursuant to Article
X of the  Collaboration  Agreement,  Purchaser shall have the right to cause the
Company to file a registration  statement  under the Securities Act for a public
offering of all or part of the Shares, but in no event less than 100,000 Shares,
beneficially  owned by Purchaser by  delivering  written  notice  thereof to the
Company  specifying the number of Shares to be included in such registration and
the intended method of distribution thereof (the "Registration  Request").  Upon
receipt of the  Registration  Request,  the Company shall, as  expeditiously  as
possible,  use its best efforts to promptly  effect the  registration  under the
Securities  Act,  and  all  applicable  state  securities  laws,  to the  extent
necessary to permit the sale or other  disposition by Purchaser of the Shares to
be so registered in accordance with such notice.

                  (b) The demand  registration  rights granted in Section 3.9(a)
are subject to the following limitations: (i) the Company shall not be obligated
to effect  more than one  registration  pursuant  to  Section  3.9(a),  (ii) the
Company  shall not be obligated to effect such  registration  for a period of 60
days following the closing of an  underwritten  public offering of the Company's
equity  securities  that is in  registration  at the time of the  receipt of the
Registration Request (provided that the period within which Purchaser may demand
registration  hereunder  will be  extended  by the  number  of days by which the
registration  requested by Purchaser is delayed pursuant to this sentence);  and
(iii) if the Company  shall  furnish to  Purchaser a  certificate  signed by the
Chairman of the Board of Directors of the Company stating that in the good faith
judgment  of the  Board of  Directors  of the  Company,  it  would be  seriously
detrimental  to the Company and its  stockholders  for such  registration  to be
effected at such time, then the Company shall have the right to defer the filing
of the  registration for a period of not more than 180 days after receipt of the
Registration Request (provided that the period within which



                                       6.

<PAGE>

Purchaser may demand  registration  hereunder  will be extended by the number of
days by which the  registration  requested by  Purchaser is delayed  pursuant to
this sentence).

                  (c) In addition to the rights provided by Section  3.9(a),  if
the Additional Shares are not freely transferable  without restriction under the
Securities  Act,  within  90 days  immediately  following  the  purchase  of the
Additional  Shares,  the Company shall file a registration  statement  under the
Securities Act for a public offering of the Additional Shares.

                  (d) If and when the Company is required by the  provisions  of
Section  3.9(a) or (c) to include  any of the Shares or  Additional  Shares in a
registration  under the Securities  Act,  Purchaser will furnish in writing such
information  as is  reasonably  requested  by the Company for  inclusion  in the
registration  statement relating to such offering and such other information and
documentation as the Company shall reasonably request,  and the Company will, as
expeditiously as possible:

                           (i) Prepare and file with the Securities and Exchange
Commission ("SEC") a registration  statement with respect to such securities and
use its best efforts to cause such  registration to become and remain  effective
(i) with  respect to the Shares,  for such period as may be  necessary to permit
the  successful  marketing  of such  securities,  but  not  exceeding  120  days
(excluding  any period  during  which a stop  order is in effect)  and (ii) with
respect to the Additional  Shares,  until such time as the Additional Shares are
freely transferable without restriction under the Securities Act.

                           (ii)  Prepare  and file with the SEC such  amendments
and  supplements  to such  registration  statement  and the  prospectus  used in
connection  therewith as may be necessary to comply with the  provisions  of the
Securities Act and to keep such registration statement effective for that period
of time specified in paragraph (i) of this section.

                           (iii)   Furnish   to   Purchaser   such   number   of
prospectuses and preliminary prospectuses in conformity with the requirements of
the  Securities  Act and such other  documents as such  Purchaser may reasonably
request in order to  facilitate  the  public  sale or other  disposition  of the
Shares or Additional Shares registered hereunder.

                           (iv) Use its best  efforts to register or qualify the
Shares or Additional  Shares covered by such  registration  statement under such
other  securities  or blue sky laws of such  jurisdictions  as  Purchaser  shall
reasonably  request  and do any and all  other  acts  and  things  which  may be
necessary  or desirable to enable  Purchaser  to  consummate  the public sale or
other  disposition  in such  jurisdictions  of the Shares or  Additional  Shares
covered by such registration  statement,  provided that the Company shall not be
required in  connection  therewith  or as a  condition  thereto to qualify to do
business  or to file a general  consent to service of process in any such states
or jurisdictions.

                  (e) In the  event of a  registration  of any of the  Shares or
Additional  Shares under the Securities Act pursuant to Section 3.9(a) or (c) in
connection with an underwritten



                                       7.

<PAGE>

public offering,  the Company will enter into and perform its obligations  under
an  underwriting  agreement,  in usual and  customary  form,  with the  managing
underwriters of such offering,  including without limitation providing usual and
customary  indemnification.  In the event  Purchaser  proposes to sell Shares or
Additional  Shares in accordance  with this Section  pursuant to an underwritten
offering,  the Company shall have the right to approve the managing underwriters
for  such  offering;   provided,  however,  that  such  approval  shall  not  be
unreasonably withheld.

                  (f) At any time or from time to time  following the earlier of
(i) the  expiration of initial  Research  Term (as defined in the  Collaboration
Agreement)  without  giving effect to any extension  thereof or (ii) the earlier
termination  of the  Research  Term  pursuant to Article X of the  Collaboration
Agreement,  if the Company  shall  determine to register  any of its  securities
under the Securities Act either for its own account or the account of a security
holder or holders exercising their respective demand registration  rights, other
than a registration relating solely to employee benefit plans, or a registration
relating solely to a Rule 145 transaction, or a registration on any registration
form that does not permit secondary sales, then the Company will:

                           (i)  promptly  give to  Purchaser  a  written  notice
thereof; and

                           (ii)  use  its  best   efforts  to  include  in  such
registration  (and  any  related  qualification  under  blue  sky  laws or other
compliance),   except  as  set  forth  in  Section  3.9(g)  below,  and  in  any
underwriting  involved therein, all of the Shares specified in a written request
or requests  made by Purchaser  and received by the Company  within  twenty (20)
days after the written notice from the Company  described in clause (i) above is
mailed or delivered by the  Company.  Such written  request may specify all or a
part of the Shares.

                  (g) If the  registration  of which the Company gives notice to
Purchaser is for a registered  public offering  involving an  underwriting,  the
Company shall so advise Purchaser as a part of the written notice given pursuant
to Section  3.9(f)(i).  In such event,  the right of Purchaser  to  registration
pursuant to Section 3.9(f) shall be conditioned upon  Purchaser's  participation
in  such  underwriting  and  the  inclusion  of all or any  part  of the  Shares
specified  in  Purchaser's  notice in the  underwriting  to the extent  provided
herein.  Purchaser  shall  (together  with the Company and the other  holders of
securities  of the  Company  with  registration  rights to  participate  therein
distributing  their  securities   through  such  underwriting)   enter  into  an
underwriting  agreement  in  customary  form  with  the  representative  of  the
underwriter or underwriters selected by the Company.

         Notwithstanding  any other  provision of Sections 3.9(f) or (g), if the
representative of the underwriters advises the Company in writing that marketing
factors  require a limitation  on the number of shares to be  underwritten,  the
representative  may (subject to the  limitations set forth below) exclude all of
the  Shares  from,  or limit  the  number  of  Shares  to be  included  in,  the
registration and  underwriting.  The Company shall so advise Purchaser and other
holders of securities requesting registration, and the number of shares that are
entitled to be included in the



                                       8.

<PAGE>

registration  and  underwriting  shall be  allocated  first to the  Company  for
securities  being sold for its own account and  thereafter  the number of shares
that are entitled to be included in the  registration  shall be allocated  among
Purchaser and other holders requesting  inclusion of shares on a pro rata basis,
subject to any prior  agreements  among the Company and its other  stockholders,
but only to the  extent  that  such  other  agreements  provide  for  additional
limitations on the number of shares such other  stockholders or the Company will
be entitled to include in the registration, which agreements are in effect as of
the Effective Date. If Purchaser or any other person does not agree to the terms
of any such underwriting,  Purchaser and any other such person shall be excluded
therefrom by written notice from the Company or the  underwriter.  Any Shares or
other  securities  excluded or withdrawn  from such  underwriting  shall also be
withdrawn from such registration.

                  (h) As used  herein,  "Registration  Expenses"  shall mean all
expenses incurred by the Company in complying with this Section 3.9,  including,
without  limitation,  all registration,  qualification and filing fees; printing
expenses;  fees and  disbursements  of counsel for the Company (and the fees and
disbursements  of  counsel  for the  Company in its  capacity  as counsel to the
Purchaser hereunder;  if Company counsel does not make itself available for this
purpose,  the Company  will pay the  reasonable  fees and  disbursements  of one
counsel  for the  Purchaser  as  selected  by  Purchaser)  and of the  Company's
independent accounting firm; blue sky fees and expenses;  underwriting discounts
and commissions and the expense of any special audits incident to or required by
any such  registration  (but excluding the compensation of regular  employees of
the Company which shall be paid in any event by the Company). Purchaser will pay
all Registration  Expenses in connection with a registration pursuant to Section
3.9(a) hereof;  provided,  however,  that in the event  Purchaser  withdraws its
demand for registration after having learned of a material adverse change in the
condition, business, or prospects of the Company from that known to Purchaser at
the time of its demand (in which case Purchaser shall retain its rights pursuant
to Section 3.9(a)), all Registration Expenses shall be borne by the Company. All
Registration  Expenses in connection with any  registration  pursuant to Section
3.9(c) and (f) hereof shall be borne by the Company; provided, however, that any
incremental  filing fees or other  expenses  incurred  by the Company  solely by
reason of Purchaser's exercise of registration rights pursuant to Section 3.9(f)
shall be borne by the Purchaser.

                  (i) The rights conferred upon Purchaser under this Section 3.9
may be assigned by Purchaser to any  permitted  transferee  of the Shares or the
Additional Shares, as applicable, provided that each such transfer complies with
Section 4.5, and provided,  further,  that only Purchaser shall be authorized to
give notice to the Company of any request for registration  under Section 3.9(a)
and only  Purchaser  shall be  entitled  to receive  notice  pursuant to Section
3.9(c) hereof.

                  (j) In the event any Shares or Additional  Shares are included
in a registration statement under Sections 3.9(a), (c) or (f):

                           (i) To the extent  permitted by law, the Company will
indemnify and hold harmless  Purchaser,  the partners,  officers,  directors and
legal counsel of Purchaser, any



                                       9.

<PAGE>

underwriter (as defined in the Securities Act) for Purchaser and each person, if
any,  who  controls  Purchaser  or such  underwriter  within the  meaning of the
Securities Act or the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), against any losses, claims, damages, or liabilities (joint or several) to
which they may become  subject  under the  Securities  Act,  the Exchange Act or
other  federal  or  state  law,  insofar  as such  losses,  claims,  damages  or
liabilities  (or actions in respect  thereof) arise out of or are based upon any
of  the  following   statements,   omissions  or  violations   (collectively   a
"Violation")  by the  Company:  (a)  any  untrue  statement  or  alleged  untrue
statement of a material fact contained in such registration statement, including
any  preliminary  prospectus  or  final  prospectus  contained  therein  or  any
amendments or supplements thereto, (b) 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,  or (c) any violation or alleged violation by
the Company of the Securities Act, the Exchange Act, any state securities law or
any rule or regulation promulgated under the Securities Act, the Exchange Act or
any  state  securities  law in  connection  with the  offering  covered  by such
registration  statement;  and the  Company  will  reimburse  Purchaser  and each
partner, officer or director, underwriter or controlling person for any legal or
other expenses  reasonably  incurred by them in connection with investigating or
defending any such loss, claim, damage,  liability or action;  provided however,
that the indemnity agreement contained in this Section 3.9(j)(i) shall not apply
to amounts paid in  settlement  of any such loss,  claim,  damage,  liability or
action if such settlement is effected without the consent of the Company,  which
consent shall not be unreasonably  withheld,  nor shall the Company be liable in
any such  case for any such  loss,  claim,  damage,  liability  or action to the
extent  that it  arises  out of or is based  upon a  Violation  which  occurs in
reliance upon and in conformity with written information furnished expressly for
use in connection with such registration by Purchaser or such partner,  officer,
director, underwriter or controlling person of Purchaser.

                           (ii) To the extent  permitted by law,  Purchaser will
indemnify and hold harmless the Company, each of its directors, its officers and
legal  counsel and each person,  if any,  who  controls  the Company  within the
meaning of the  Securities  Act, any  underwriter  and any other person  selling
securities  under such  registration  statement  or any of such  other  person's
partners,  directors or officers or any person who controls such person, against
any  losses,  claims,  damages or  liabilities  (joint or  several) to which the
Company or any such director, officer,  controlling person, underwriter or other
such person, or partner,  director, officer or controlling person of such person
may become subject under the  Securities  Act, the Exchange Act or other federal
or state law, insofar as such losses, claims, damages or liabilities (or actions
in respect  thereto) arise out of or are based upon any Violation,  in each case
to the extent (and only to the extent)  that such  Violation  occurs in reliance
upon and in conformity with written information  furnished by Purchaser under an
instrument duly executed by Purchaser and stated to be  specifically  for use in
connection  with such  registration;  and Purchaser  will reimburse any legal or
other expenses reasonably incurred by the Company or any such director, officer,
controlling person,  underwriter or other person, or partner,  officer, director
or controlling  person of such other person in connection with  investigating or
defending any such loss, claim, damage,  liability or action if it is judicially
determined  that  there  was  such a  Violation;  provided,  however,  that  the
indemnity agreement contained in this Section 3.9(j)(ii)



                                       10.

<PAGE>

shall not apply to amounts paid in settlement of any such loss,  claim,  damage,
liability  or action if such  settlement  is  effected  without  the  consent of
Purchaser,  which consent shall not be unreasonably withheld;  provided further,
that in no event shall any indemnity  under this Section  3.9(j)(ii)  exceed the
net proceeds from the offering received by such Purchaser

                           (iii) Promptly after receipt by an indemnified  party
under this Section 3.9(j) of notice of the commencement of any action (including
any governmental  action),  such  indemnified  party will, if a claim in respect
thereof is to be made against any indemnifying  party under this Section 3.9(j),
deliver to the indemnifying  party a written notice of the commencement  thereof
and the  indemnifying  party shall have the right to participate in, and, to the
extent the indemnifying  party so desires,  jointly with any other  indemnifying
party similarly  noticed,  to assume the defense  thereof with counsel  mutually
satisfactory to the parties; provided,  however, that an indemnified party shall
have the right to retain its own counsel,  with the fees and expenses to be paid
by the indemnifying  party, if  representation  of such indemnified party by the
counsel retained by the indemnifying  party would be inappropriate due to actual
or potential  differing  interests  between such indemnified party and any other
party  represented  by such counsel in such  proceeding.  The failure to deliver
written  notice  to the  indemnifying  party  within  a  reasonable  time of the
commencement  of any such action,  if materially  prejudicial  to its ability to
defend such action,  shall relieve such  indemnifying  party of any liability to
the indemnified party under this Section 3.9(j),  but the omission so to deliver
written  notice to the  indemnifying  party will not relieve it of any liability
that it may have to any  indemnified  party  otherwise  than under this  Section
3.9(j).

                           (iv)  If the  indemnification  provided  for in  this
Section 3.9(j) is held by a court of competent jurisdiction to be unavailable to
an indemnified party with respect to any losses,  claims, damages or liabilities
referred  to  herein,  the  indemnifying  party,  in lieu of  indemnifying  such
indemnified  party  thereunder,  shall to the extent permitted by applicable law
contribute to the amount paid or payable by such  indemnified  party as a result
of such loss, claim, damage or liability in such proportion as is appropriate to
reflect the relative fault of the indemnifying  party on the one hand and of the
indemnified party on the other in connection with the Violation(s) that resulted
in such  loss,  claim,  damage  or  liability,  as well  as any  other  relevant
equitable  considerations.  The relative fault of the indemnifying  party and of
the  indemnified  party shall be  determined  by a court of law by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or the omission to state a material fact relates to information supplied by
the  indemnifying  party or by the indemnified  party and the parties'  relative
intent,  knowledge,  access to information and opportunity to correct or prevent
such statement or omission; provided, that in no event shall any contribution by
Purchaser hereunder exceed the proceeds from the offering received by Purchaser.

                           (v) The  obligations  of the  Company  and  Purchaser
under this Section 3.9(j) shall survive completion of any offering of securities
in a registration  statement pursuant to Section 3.9. No indemnifying  party, in
the defense of any such claim or litigation,  shall,  except with the consent of
each  indemnified  party,  consent  to entry of any  judgment  or enter into any
settlement which does not include as an unconditional term thereof the giving by
the



                                       11.

<PAGE>

claimant or plaintiff to such indemnified  party of a release from all liability
in respect to such claim or litigation.

                  (k) If Purchaser  purchases the Additional Shares in a private
offering in which  investors  obtain  registration  rights,  Purchaser  shall be
entitled to either the registration rights provided to investors in such private
offering or the registration rights provided herein, in its discretion.

         3.10  Covenant  to  Keep  Public  Information  Available.  The  Company
covenants  and agrees that it will file the  reports  required to be filed by it
under the  Securities  Act and the  Exchange  Act and the rules and  regulations
adopted  by the SEC  thereunder  as such may be  amended  from time to time (the
"Rules"),  and will  take such  further  actions  as  Purchaser  may  reasonably
request,  all to the extent  required  from time to time to enable  Purchaser to
sell  Shares  at  such  times  as  are  permitted  by  this  Agreement   without
registration  under the Securities Act within the limitations of Rule 144 of the
Rules or any similar rule or regulation  hereafter  adopted by the SEC. Upon the
request of  Purchaser,  the Company  will supply  Purchaser  with a  certificate
certifying compliance with this provision.

         3.11 SEC  Reports.  All of the reports  filed by the Company  under the
Exchange Act prior to the date of this Agreement  (the "SEC Reports")  comply in
all material respects with the requirements of the Exchange Act. None of the SEC
Reports contains,  as of the respective dates thereof, any untrue statement of a
material fact or omits to state any material fact required to be stated  therein
or  necessary  to make the  statements  therein not  misleading  in light of the
circumstances under which they were made.

         3.12   Securities  Law   Compliance.   Assuming  the  accuracy  of  the
representations  and warranties of Purchaser  contained in Section 4, the offer,
issuance, sale and delivery of the Shares constitute an exempt transaction under
the  Securities  Act, and the offer,  issuance,  sale and delivery of Additional
Shares  pursuant to Section 1.2 shall be made in compliance  with the Securities
Act.

         3.13  Registration  Rights.  Except  as set  forth in the  Schedule  of
Exceptions,  the  Company is not under any  obligation  to  register  any of its
presently outstanding securities or any of its securities which may hereafter be
issued.

4.       REPRESENTATIONS, WARRANTIES AND COVENANTS OF PURCHASER.

         Purchaser hereby represents, warrants and covenants with the Company as
follows:

         4.1 Legal Power.  Purchaser has the requisite  partnership power and is
authorized to enter into this Agreement, to purchase the Shares hereunder and to
carry out and perform its obligations under the terms of this Agreement.



                                       12.

<PAGE>

         4.2 Due Execution. This Agreement has been duly authorized executed and
delivered by Purchaser, and upon due execution and delivery by the Company, this
Agreement will be a valid and binding agreement of Purchaser.

         4.3      Investment Representations and Covenants.

         Purchaser is acquiring  the Shares for its own account,  not as nominee
or agent,  for  investment  and not with a view to or for  resale in  connection
with,  any  distribution  or public  offering  thereof within the meaning of the
Securities Act.  Purchaser  understands that the Shares have not been registered
under the  Securities  Act, but are instead  being offered and sold to Purchaser
pursuant to an exemption from registration contained in the Securities Act based
in part upon the following representations and warranties:

                  (a) Purchaser is capable of evaluating the merits and risks of
its investment in the Company and has the capacity to protect its own interests.
Purchaser must bear the economic risk of this  investment  unless the Shares are
registered  pursuant to the Securities Act, or an exemption from registration is
available.  Purchaser  understands that the Company has no present  intention of
registering the Shares.  Purchaser also  understands  that there is no assurance
that any exemption from registration  under the Securities Act will be available
and that,  even if available,  such  exemption  may not allow such  Purchaser to
transfer  all or any  portion  of the  Shares  under the  circumstances,  in the
amounts or at the times Purchaser might propose.

                  (b) Purchaser is acquiring the Shares for such Purchaser's own
account for investment only, and not with a view towards their distribution.

                  (c)  Purchaser  represents  that by reason  of its,  or of its
management's,  business or financial  experience,  Purchaser has the capacity to
protect its own interests in connection  with the  transactions  contemplated in
this Agreement.

                  (d) Purchaser has had an  opportunity to discuss the Company's
business,   management  and  financial  affairs  with  directors,  officers  and
management  of the Company and has had the  opportunity  to review the Company's
operations  and  facilities.  Purchaser  has  also  had the  opportunity  to ask
questions of and receive answers from, the Company and its management  regarding
the terms and conditions of this investment.

                  (e) Purchaser  acknowledges and agrees that the Shares must be
held indefinitely  unless they are subsequently  registered under the Securities
Act or an exemption  from such  registration  is  available.  Purchaser has been
advised  or is  aware  of the  provisions  of Rule  144  promulgated  under  the
Securities  Act, which permits  limited resale of shares  purchased in a private
placement subject to the satisfaction of certain  conditions,  including,  among
other things:  the availability of certain current public  information about the
Company,  the  resale  occurring  not less  than  two  years  after a party  has
purchased  and paid for the  security  to be sold,  the sale  being  through  an
unsolicited  "broker's  transaction" or in  transactions  directly with a market
maker (as said term is defined under the Exchange Act) and the number of shares



                                       13.

<PAGE>

being sold during any three-month  period not exceeding  specified  limitations.
Each certificate representing the Shares shall be stamped or otherwise imprinted
with a legend substantially similar to the following:

         THE SECURITIES  REPRESENTED  HEREBY HAVE NOT BEEN REGISTERED  UNDER THE
         SECURITIES  ACT OF 1933 (THE  "ACT")  AND MAY NOT BE  OFFERED,  SOLD OR
         OTHERWISE  TRANSFERRED,  ASSIGNED,  PLEDGED OR HYPOTHECATED  UNLESS AND
         UNTIL THEY ARE  REGISTERED  UNDER THE ACT OR UNLESS (A) THE COMPANY HAS
         RECEIVED  AN OPINION OF COUNSEL  SATISFACTORY  TO THE  COMPANY  AND ITS
         COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED OR (B) SUCH SALE IS MADE
         PURSUANT TO RULE 144 UNDER THE ACT.

         4.4 Standstill Covenant.  Purchaser agrees that prior to the earlier of
(i) the  expiration of initial  Research  Term (as defined in the  Collaboration
Agreement)  without  giving effect to any extension  thereof or (ii) the earlier
termination  of the  Research  Term  pursuant to Article X of the  Collaboration
Agreement,  neither  Purchaser  nor any of its  affiliates  will in any  manner,
directly or indirectly  (i) other than as permitted by this  Agreement,  effect,
seek,  offer or propose to effect any acquisition of any securities or assets of
the  Company,  any  tender or  exchange  offer,  merger,  business  combination,
recapitalization or other extraordinary transaction involving the Company or any
solicitation  of  proxies  or  consents  to vote any  voting  securities  of the
Company,  (ii) form,  join or in any way participate in a "group" (as defined in
the Exchange Act) with respect to any voting  securities  of the Company,  (iii)
solicit or participate in any  solicitation of proxies  relating to the election
of  directors of the Company,  or (iv) enter into any  agreement  with any other
person with  respect to the  foregoing,  or assist any other person to do any of
the foregoing; provided that (A) Purchaser may purchase additional securities in
an  amount  sufficient  to  allow  Purchaser  to own  up to  4.9%  of  the  then
outstanding  shares of Common Stock of the Company  (excluding any shares issued
directly to Purchaser or its  affiliates  by the  Company);  (B) the transfer of
Shares in accordance  with Section 4.5 and the voting  thereof by the transferee
shall not be deemed a prohibited group formation or proxy solicitation;  (C) the
restrictions  contained in this Section shall terminate  automatically  upon the
acquisition by any person or group (as defined in the Exchange Act),  other than
Purchaser  and  its  affiliates,  of more  than  20% of the  outstanding  voting
securities  of the Company or upon the  commencement  (as provided in Rule 14d-2
under  the  Exchange  Act) of a  tender  offer  other  than by or on  behalf  of
Purchaser  or its  affiliates  (with  securities  or  cash)  which  has not been
approved by a majority of the  Company's  Board of Directors  for the  Company's
voting  securities and (D) this sentence  shall not prohibit the  acquisition or
disposition  of shares for  investment  purposes  only in the open market in the
ordinary  course by any pension  fund or trust for the benefit of  employees  of
Purchaser or its affiliates.

         4.5 Lockup Covenant.  Purchaser agrees that prior to the earlier of (i)
the  expiration of the initial  Research  Term (as defined in the  Collaboration
Agreement)  without giving effect to any extensions  thereof or (ii) the earlier
termination  of the  Research  Term  pursuant to Article X of the  Collaboration
Agreement, Purchaser will not, without the prior written approval of the



                                       14.

<PAGE>

Company,  offer,  sell or  otherwise  dispose of,  directly or  indirectly,  any
capital  stock of the Company which  Purchaser  may own directly,  indirectly or
beneficially;  provided  that (i)  Purchaser  may  transfer  some or all of such
capital  stock (A) pursuant to and in  accordance  with the terms of any merger,
consolidation,   reclassification   of  shares  or  capital   reorganization  of
Purchaser,  or  pursuant to a sale of all or  substantially  all of the stock or
assets of Purchaser; and (B) to a corporation, partnership or other legal entity
of which Purchaser is in control of, under common control with or controlled by,
but only if such transferee agrees in writing to hold such capital stock subject
to all of the provisions of this Agreement and to transfer such capital stock to
Purchaser if such  transferee  ceases to be in control of, under common  control
with or controlled by Purchaser (all such capital stock so transferred  shall be
deemed to be shares held by  Purchaser  for all  purposes  hereunder),  (ii) the
restrictions  contained in this sentence shall terminate  automatically upon the
acquisition by any person or group (as defined in the Exchange Act),  other than
Purchaser  and  its  affiliates,  of more  than  20% of the  outstanding  voting
securities  of the  Company,  and (iii) this  sentence  shall not  prohibit  the
acquisition or  disposition  of shares for investment  purposes only in the open
market in the  ordinary  course by any pension  fund or trust for the benefit of
employees of Purchaser or its affiliates.

         4.6 Right of First  Offer.  Purchaser  agrees that  Purchaser  will not
sell,  assign,  pledge, or in any manner transfer any of the Shares or any right
or interest  therein,  whether  voluntarily or by operation of law,  except by a
transfer which meets the  requirements set forth elsewhere in this Agreement and
hereinafter set forth in this Section 4.6:

                  (a) If  Purchaser  receives  from  anyone  a bona  fide  offer
acceptable to Purchaser to purchase any of the Shares, or intends to make a bona
fide offer to sell any Shares,  then  Purchaser  shall first give written notice
thereof to the Company. The notice shall name the proposed transferee, if known,
and state the number of shares to be transferred,  the price per share or method
for determining the price and all other terms and conditions of the offer.

                  (b) For five  (5)  business  days  following  receipt  of such
notice, the Company shall have the option to purchase all of the shares (but not
less than all) specified in the notice at the price and upon the terms set forth
in such bona fide  offer.  In the event the Company  elects to purchase  all the
shares,  it shall give  written  notice to the  Purchaser  of its  election  and
settlement for said shares shall be made as provided below in paragraph (c).

                  (c) In the event the  Company  elects  to  acquire  any of the
Shares as specified in Purchaser's notice, the Company shall so notify Purchaser
and settlement thereof shall be made in cash within ten (10) business days after
the Company receives  Purchaser's notice;  provided that if the terms of payment
set forth in  Purchaser's  notice  were other than cash  against  delivery,  the
Company shall pay for said shares on the same terms and  conditions set forth in
Purchaser's notice.

                  (d) In the event the Company  does not elect to acquire all of
the shares specified in Purchaser's notice,  Purchaser may, within the sixty-day
period  following the  expiration  of the option  rights  granted to the Company
herein, sell elsewhere the shares specified



                                       15.

<PAGE>

in Purchaser's notice which were not acquired by the Company, in accordance with
the provisions of this Agreement,  provided that said sale shall not be on terms
and conditions more favorable to Purchaser than those contained in the bona fide
offer set forth in Purchaser's notice.


                  (e) Anything to the contrary contained herein notwithstanding,
the following  transactions  shall be exempt from the provisions of this Section
4.6:

                           (i) A transfer  of any or all of the Shares  pursuant
to  and  in   accordance   with  the   terms  of  any   merger,   consolidation,
reclassification of shares or capital  reorganization of Purchaser,  or pursuant
to a sale of all or substantially all of the stock or assets of Purchaser; and

                           (ii) A  transfer  of any  or all of the  Shares  to a
corporation,  partnership or other legal entity of which Purchaser is in control
of, under  common  control with or  controlled  by, but only if such  transferee
agrees in writing to hold such Shares  subject to all of the  provisions of this
Agreement and to transfer such Shares to Purchaser if such transferee  ceases to
be in control of, under common control with or controlled by Purchaser (all such
Shares so  transferred  shall be deemed to be shares held by  Purchaser  for all
purposes hereunder).

                           In any such case, the transferee,  assignee, or other
recipient  shall receive and hold such stock  subject to the  provisions of this
Agreement,  and there  shall be no  further  transfer  of such  stock  except in
accordance with this Agreement.

                  (f) Any sale or transfer,  or purported  sale or transfer,  of
Shares shall be null and void unless the terms,  conditions  and  provisions  of
this Agreement are strictly observed and followed.

                  (g) The  foregoing  right of first  offer shall  terminate  on
either of the following dates, whichever shall first occur:

                           (i) The earlier of (i) the expiration of the Research
Term (as  defined  in the  Collaboration  Agreement)  including  any  extensions
thereof or (ii) the earlier termination of the Research Term pursuant to Article
X of the Collaboration Agreement; or

                           (ii) Upon the  registration of the Shares pursuant to
a registration  statement  filed with, and declared  effective by, the SEC under
the Securities Act.

                  (h) The certificate  representing the Shares shall bear on its
face the following  legend so long as the foregoing right of first offer remains
in effect:



                                       16.

<PAGE>

                  "The shares  represented by this  certificate are subject to a
         right of first offer option in favor of the Company, as provided in the
         Common Stock Purchase  Agreement  dated as of September 30, 1996 by and
         between the Company and Vision Pharmaceuticals L.P.

5.       MISCELLANEOUS.

         5.1 Governing  Law. This  Agreement  shall be governed by and construed
under  the laws of the  State of  California  as  applied  to  agreements  among
California  residents,  made and to be  performed  entirely  within the State of
California, without regard to principles of conflict of laws.

         5.2  Successors  and Assigns.  Except as otherwise  expressly  provided
herein,  the  provisions  hereof  shall  inure to the benefit of, and be binding
upon, the successors,  assigns,  heirs,  executors,  and  administrators  of the
parties hereto.

         5.3 Entire Agreement.  This Agreement and the Exhibits hereto,  and the
other  documents  delivered  pursuant  hereto,  constitute  the full and  entire
understanding and agreement among the parties with regard to the subjects hereof
and no party  shall be liable or bound to any other  party in any  manner by any
representations, warranties, covenants, or agreements except as specifically set
forth  herein or therein.  Nothing in this  Agreement,  express or  implied,  is
intended  to confer  upon any  party,  other than the  parties  hereto and their
respective  successors  and  assigns,  any  rights,  remedies,  obligations,  or
liabilities under or by reason of this Agreement,  except as expressly  provided
herein.

         5.4  Separability.  In case any  provision of this  Agreement  shall be
invalid,  illegal,  or  unenforceable,  it shall to the extent  practicable,  be
modified so as to make it valid,  legal and  enforceable and to retain as nearly
as  practicable  the intent of the  parties,  and the  validity,  legality,  and
enforceability  of the remaining  provisions shall not in any way be affected or
impaired thereby.

         5.5 Amendment and Waiver. Except as otherwise provided herein, any term
of this  Agreement  may be  amended,  and  the  observance  of any  term of this
Agreement may be waived (either  generally or in a particular  instance,  either
retroactively  or  prospectively,  and either for a specified  period of time or
indefinitely),  with the  written  consent of the  Company  and  Purchaser.  Any
amendment or waiver  effected in  accordance  with this section shall be binding
upon any  holder of any  security  purchased  under  this  Agreement  (including
securities into which such securities have been  converted),  each future holder
of all such securities, and the Company.

         5.6 Notices. All notices and other communications required or permitted
hereunder  shall be in  writing  and  shall be  deemed  effectively  given  upon
personal  delivery,  on the first  business day  following  mailing by overnight
courier,  or on the fifth day following mailing by registered or certified mail,
return  receipt  requested,  postage  prepaid,  addressed  to  the  Company  and
Purchaser at the addresses included herein.



                                       17.

<PAGE>

         5.7 Fees and Expenses.  The Company and Purchaser  shall bear their own
expenses  and legal fees with  respect to this  Agreement  and the  transactions
contemplated hereby.

         5.8  Titles  and   Subtitles.   The  titles  of  the   paragraphs   and
subparagraphs  of this  Agreement are for  convenience of reference only and are
not to be considered in construing this Agreement.

         5.9  Counterparts.  This  Agreement  may be  executed  in any number of
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute one instrument.

         5.10  Consent  to  Jurisdiction  and  Venue.  Any claim or  controversy
arising  out of or  related to this  Agreement  or any  breach  hereof  shall be
submitted to a court of applicable  jurisdiction  in the State of California and
each party hereby consents to the jurisdiction and venue of such court.

         5.11 Guarantee.  Allergan guarantees the performance of each obligation
of  Purchaser  under this  Agreement,  whether or not  Allergan has received any
notice which is to be provided to Purchaser pursuant to this Agreement.




                                       18.

<PAGE>


         IN WITNESS WHEREOF,  the parties hereto have executed this Common Stock
Purchase Agreement as of the date set forth in the first paragraph hereof.

                                 SUGEN, INC.



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

                                 Address:        515 Galveston Drive
                                                 Redwood City, CA 94063-4720


                                 VISION PHARMACEUTICALS L.P., A TEXAS LIMITED
                                 PARTNERSHIP DBA ALLERGAN
                                 By: Allergan General, Inc.
                                 Its: General Partner


                                 By:   /s/ Francis R. Tunney
                                    -------------------------------------------

                                           Francis R. Tunney
                                           Secretary

                                 Address:  c/o Allergan, Inc.
                                           2525 Dupont Drive
                                           Irvine, CA 92612

                                 Guarantee of performance given by:


                                 ALLERGAN, INC.

                                 By:  /s/ Francis R. Tunney
                                    -------------------------------------------

                                          Name:  Francis R. Tunney, Jr.
                                          Title: Corporate Vice President
                                                 and General Counsel


                                 Address:        2525 Dupont Drive
                                                 Irvine, CA 92612


                                       19.

<PAGE>

                                    EXHIBIT A

                              FORM OF OPINION FROM
                     COOLEY GODWARD CASTRO HUDDLESON & TATUM


Organization. The Company is a corporation, duly incorporated,  validly existing
and in good standing under the laws of the  jurisdiction  of its  incorporation.
The Company has all requisite power and authority to own or lease its properties
and to conduct its  business as now  conducted.  The Company is  qualified  as a
foreign  corporation  and is in good standing in all states where the conduct of
its   business  or  its   ownership  or  leasing  of  property   requires   such
qualification,  except where the failure to so qualify would not have a material
adverse effect on the business,  financial condition or results of operations of
the Company taken as a whole.

Authority.  The Company has all requisite power and authority to enter into this
Agreement, and to consummate the transactions contemplated hereby. The execution
and  delivery  of  this  Agreement  and  the  Collaboration  Agreement  and  the
consummation of the transactions  contemplated hereby and thereby have been duly
authorized by all  necessary  corporate  action on the part of the Company,  and
upon execution and delivery by the Company, this Agreement and the Collaboration
Agreement  will  constitute  valid  and  binding  obligations  of  the  Company,
enforceable  against  the Company in  accordance  with their  respective  terms,
subject to applicable  bankruptcy,  insolvency,  reorganization,  moratorium and
similar  laws  relating to or affecting  creditor's  rights from time to time in
effect and subject to general equity principles.

Shares validly issued.  The Shares have been duly authorized,  and upon issuance
and  delivery  against  payment  therefor  in  accordance  with the terms of the
Agreement, will be validly issued, outstanding, fully paid and nonassessable.





<PAGE>

                                    EXHIBIT B

                  SCHEDULE OF EXCEPTIONS PURSUANT TO SECTION 3


         This Schedule of Exceptions is made and given  pursuant to Section 3 of
the Agreement.  The paragraph numbers in this Schedule of Exceptions  correspond
to the paragraph numbers in the Agreement;  however,  any information  disclosed
herein  under  any  paragraph  number  shall  be  deemed  to  be  disclosed  and
incorporated  into any other  paragraph  number under the  Agreement  where such
disclosure  would be appropriate.  Any terms defined in the Agreement shall have
the same meaning when used in this  Schedule of  Exceptions  as when used in the
Agreement unless the context otherwise requires.


         3.2  Capitalization.  The  following  warrants  were  exercised for the
number of shares indicated in cashless transactions on the dates indicated:

                                           Shares         Shares         Warrant
   Date            Warrantholder           Issued       Netted Out        Total
   ----            -------------           ------       ---------         -----

 3/22/96        Silicon Valley Bank        1,811            855           2,666


  1/5/96         Western Technology        3,623           1,710          5,333
                     Investment


         On September 30, 1996,  20,410 shares of Common Stock were issued under
the Company's Employee Stock Purchase Plan.

         3.13 Registration  Rights. The Company has granted  registration rights
to the  following  security  holders  with  respect  to  the  number  of  shares
indicated:


                 Security Holder                               Number of Shares
                 ---------------                               ----------------

Asta Medica Aktiengesellschaft                                     431,137

Zeneca Limited                                                   1,071,016

AMGEN, Inc.                                                        200,000

Sanwa Business Credit Corp.                                         2,666

Dr. Heinrich Kuhn                                                  15,000

Financing for Science International, Inc.                          20,798

Genentech, Inc.                                                    133,333

Comdisco                                                           76,847








                                                                   EXHIBIT 10.58


           Certain   confidential   information   contained  in  this
           document, marked by brackets, is filed with the Securities
           and  Exchange  Commission  pursuant  to Rule  24b-2 of the
           Securities Exchange Act of 1934, as amended.




                             COLLABORATION AGREEMENT

                                 by and between

                                   SUGEN, INC.

                                       and

                          VISION PHARMACEUTICALS L.P.







   
   

<PAGE>

                                TABLE OF CONTENTS

                                                                            PAGE

1.   DEFINITIONS.............................................................  1

2.   SCOPE AND GOVERNANCE ...................................................  5

     2.1      Scope Of The Collaboration.....................................  5
     2.2      Research Management Committee..................................  5
     2.3      Research Management Committee Functions And Powers.............  6
     2.4      Information And Reports........................................  6
     2.5      RMC Dispute Resolution.........................................  6

3.   TARGET RESEARCH AND VALIDATION..........................................  6

     3.1      Testing and Validation of [  ] Target in Allergan Models.......  6
     3.2      Transfer of SUGEN Technology...................................  7
     3.3      Transfer of Allergan Technology................................  7
     3.4      Ocular Target Identification...................................  7
     3.5      Target Validation..............................................  7

4.   COMPOUND SCREENING AND SELECTION........................................  8

     4.1      Assay Development..............................................  8
     4.2      Screening To Identify Active Compounds.........................  8
     4.3      Further Investigation on Active Compounds......................  9
     4.4      Selection of Leads for Preclinical Investigation...............  9
     4.5      Selection of Drug Candidates...................................  9
     4.6      Substitution of Drug Candidate................................. 10
     4.7      Designation of Back-Up Compounds............................... 10
     4.8      Development of Drug Candidates................................. 11
     4.9      Product Development By SUGEN................................... 11
     4.10     Excluded Compounds............................................. 11

5.   LICENSE GRANTS; EXCLUSIVITY............................................. 12

     5.1      License Grants For Collaborative Research...................... 12
     5.2      Execution of Commercial License Agreement...................... 12
     5.3      Diligence Obligations; Grant Back.............................. 13
     5.4      Exclusivity.................................................... 13
     5.5      License Covenants.............................................. 14



                                       i.

<PAGE>




                                TABLE OF CONTENTS
                                   (CONTINUED)
                                                                            PAGE

6.   FEES AND PAYMENTS....................................................... 14

     6.1      Initial Research Payment....................................... 14
     6.2      Research Funding............................................... 14
     6.3      Milestone Payments To SUGEN.................................... 15
     6.4      Equity Investments............................................. 16

7.   INTELLECTUAL PROPERTY................................................... 16

     7.1      Ownership Of Technology........................................ 16
     7.2      Patent Prosecution............................................. 16
     7.3      Infringement................................................... 17
     7.4      Trademarks..................................................... 17
     7.5      Disclosure Of Inventions....................................... 17
     7.6      Cross-Licenses Regarding Compound Inventions................... 17

8.   REPRESENTATIONS AND WARRANTIES.......................................... 18

     8.1      Representations And Warranties................................. 18
     8.2      SUGEN Representations and Warranties........................... 18
     8.3      Disclaimer Concerning Technology............................... 19
     8.4      Disclaimer Concerning Library Compounds........................ 19

9.   CONFIDENTIALITY; PUBLICATION............................................ 19

     9.1      Confidentiality................................................ 19
     9.2      Authorized Disclosure.......................................... 20
     9.3      Publications................................................... 21

10.  TERM AND TERMINATION.................................................... 21

     10.1     Term Of The Agreement.......................................... 21
     10.2     Termination For Material Breach................................ 21
     10.3     Termination For Technical Failure.............................. 21
     10.4     Termination By Allergan Without Cause.......................... 22
     10.5     Accrued Rights, Surviving Obligations.......................... 22



                                       ii.

<PAGE>

                                TABLE OF CONTENTS
                                   (CONTINUED)
                                                                            PAGE

11.  INDEMNITY............................................................... 22

     11.1     Indemnification................................................ 22
     11.2     Control Of Defense............................................. 22

12.  GOVERNING LAW; DISPUTE RESOLUTION....................................... 23

     12.1     Governing Law.................................................. 23
     12.2     Legal Compliance............................................... 23
     12.3     Dispute Resolution............................................. 23
     12.4     Jurisdiction And Venue......................................... 23

13.  GENERAL PROVISIONS...................................................... 23

     13.1     Notices........................................................ 23
     13.2     Force Majeure.................................................. 24
     13.3     Entirety Of Agreement.......................................... 24
     13.4     Non Waiver..................................................... 24
     13.5     Disclaimer Of Agency........................................... 24
     13.6     Severability................................................... 24
     13.7     Affiliates; Assignment......................................... 25
     13.8     Headings....................................................... 25
     13.9     Limitation Of Liability........................................ 25
     13.10    Counterparts................................................... 25
     13.11    Public Disclosure.............................................. 25
     13.12    Guarantee...................................................... 25



                                      iii.

<PAGE>



                             COLLABORATION AGREEMENT

         THIS  COLLABORATION  AGREEMENT (the  "Agreement") is entered into as of
October 4, 1996 (the  "Effective  Date") by and between  SUGEN INC.,  a Delaware
corporation  ("SUGEN")  with its offices at 515 Galveston  Drive,  Redwood City,
California 94063-4720,  VISION PHARMACEUTICALS L.P., a Texas limited partnership
("Allergan")  with offices at 2525 Dupont Drive,  Irvine, CA 92623 and ALLERGAN,
INC., a Delaware  Corporation,  solely as a guarantor of the  performance  under
this Agreement by Vision Pharmaceuticals L.P.

                                    RECITALS

         WHEREAS,  SUGEN is a leader in the  research  and  discovery  of signal
transduction  targets and the  development  of  screening  assays  based on such
targets, for the discovery of small molecules with activities that may be useful
as human therapeutic drugs; and

         WHEREAS, SUGEN has developed screening assays based on tyrosine kinases
and phosphatases and serine-threonine kinases, including [            ], and has
identified  and/or  isolated  several  classes  of  compounds  that  are  active
inhibitors  in such  assays,  which  may be useful  as drugs  for  treatment  of
conditions or diseases caused by or relating to neovascularization; and

         WHEREAS, Allergan is engaged in the research,  development,  marketing,
manufacture  and   distribution  of  therapeutic  and   prophylactic   products,
particularly in the ophthalmic field, and has developed certain tissues and cell
lines that may be useful for identifying targets relating to [                 ]
neovascularization; and

WHEREAS, SUGEN and Allergan desire to enter into a collaborative relationship to
conduct research on signal transduction  targets,  including the [            ],
   that may be involved in modulating [              ] neovascularization and to
discover,  develop,  manufacture and market ophthalmology drug products, for use
in treating or preventing  ophthalmic  diseases including macular  degeneration,
based upon inhibition of validated signal transduction targets; and

         WHEREAS,  Allergan and SUGEN are also  entering  into a stock  purchase
agreement  under which  Allergan will purchase $4 million in SUGEN common stock,
and may purchase an additional $3 million;

         NOW, THEREFORE, in consideration of the foregoing and the covenants and
premises contained in this Agreement, the parties agree as follows:

1.       DEFINITIONS

         As used herein, the following terms shall have the following meanings:

         "Active  Compound" shall mean a chemical  compound provided by SUGEN or
Allergan  or  obtained  from a third  party for  screening  pursuant to Sections
4.2(a) and 4.2(b), that


                                       1.

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                                                CONFIDENTIAL TREATMENT REQUESTED

demonstrates  the requisite  activity  levels in a Target Assay as determined by
the RMC pursuant to Section 4.2(c), but excluding all Excluded Compounds.

         "Active  Compound  List"  shall  mean  the  list  of  Active  Compounds
described in Section 4.2(c), as updated from time to time during the Agreement.

         "Affiliate"   shall  mean  any   company  or  entity   controlled   by,
controlling,  or under  common  control  with a party  hereto and shall  include
without limitation any company fifty percent (50%) or more of whose voting stock
or participating profit interest is owned or controlled, directly or indirectly,
by a party,  and any company  which owns or  controls,  directly or  indirectly,
fifty percent (50%) or more of the voting stock of a party.

         "Allergan  Biomaterials"  shall mean those [           ] identified  in
Exhibit A  attached  hereto,  which  Allergan owns or controls,  as such Exhibit
is amended from time to time.

         "Allergan   Know-How"   shall  mean,   to  the  extent  useful  in  the
Collaboration Field, tangible or intangible know-how, trade secrets,  inventions
(whether or not patentable),  data, preclinical and clinical results,  physical,
chemical or biological  material,  and other  information  that  Allergan  owns,
controls  or to which it has a license  (with the  right to  sublicense)  on the
Effective Date, and any replication or any part of such information or material.
The Allergan Biomaterials are included within the scope of "Allergan Know-How".

         "Allergan   Patents"   shall  mean,   to  the  extent   useful  in  the
Collaboration Field, all foreign and domestic: (a) patents issued or existing as
of the Effective Date; and (b) patents issuing from patent applications that are
pending  as  of  the  Effective  Date  (including   provisionals,   divisionals,
continuations  and   continuations-in-part   of  such  applications);   and  (c)
substitutions,   extensions,   reissues,  renewals  and  inventors  certificates
relating to the foregoing  patents,  which Allergan owns or controls or to which
Allergan has a license (with the right to sublicense).

         "Allergan  Technology"  shall mean the  Allergan  Patents and  Allergan
Know-How.

         "Back-Up Compounds" shall have the meaning ascribed in Section 4.7.

         "Collaboration"  shall mean the programs of collaborative  research and
development as described in Articles 2, 3 and 4.

         "Collaboration Field" shall mean the discovery,  selection,  synthesis,
investigation,  and preclinical  and clinical  development of drugs that, [     
          ] of tyrosine kinases and tyrosine  phosphatases and  serine-threonine
kinases,  can treat or prevent human ophthalmic diseases.

         "Collaboration  Know-How" shall mean any and all tangible or intangible
know-how,  trade  secrets,   inventions  (whether  or  not  patentable),   data,
preclinical and clinical results, physical, chemical or biological material, and
other information that is (a) useful in the Licensed


                                       2.

<PAGE>

Field  and/or  that  relates  to  Active  Compounds,  and (b) that is in any way
derived from or developed pursuant to activities  undertaken by either party or,
to the extent a party is legally  free to do so,  such  party's  consultants  or
collaborators,  in the conduct of the Collaboration,  and any replication or any
part of such information or material.

         "Collaboration  Patents"  shall mean all foreign and  domestic  patents
(including   substitutions,   extensions,   reissues,   renewals  and  inventors
certificates  relating thereto) that issue from patent  applications  (including
provisionals,  divisionals,  continuations  and  continuations-in-  part of such
applications)  that claim inventions in the Collaboration  Know-How and that are
filed by or on behalf of one or both of the parties hereto.

         "Collaboration Technology" shall mean the Collaboration Patents and the
Collaboration Know-How.

         "Compound Invention" shall have the meaning ascribed in Section 7.1.

         "Confidential  Information"  shall  mean all  information,  inventions,
know-how or data  disclosed by a party to the other  pursuant to this  Agreement
including, without limitation,  manufacturing,  marketing, financial, personnel,
scientific and other business  information and plans,  and the material terms of
this Agreement, whether in oral, written, graphic or electronic form.

         "Derivative Compound" shall mean a compound that is an analog, homolog,
or isomer of an Active  Compound,  resulting from  Allergan's or its Affiliate's
activities  during the Term of the  Agreement,  whether  made under an analoging
program,   or  a  chemical   synthesis   program  based  on   structure-function
relationships, or otherwise.

         "Drug  Candidate"  shall mean the Active  Compound  selected  as a Drug
Candidate by Allergan pursuant to Section 4.5 for clinical  development,  or the
substitute for any such compound as designated under Section 4.6.

         "Excluded Compound" shall have the meaning ascribed in Section 4.10.

         "GLP Tox" shall mean toxicology  studies carried out in accordance with
Good Laboratory  Practice,  as described in 21 C.F.R. ss. 312 as revised, or the
European equivalent.

         "Grant-Back License" shall have the meaning ascribed in Section 5.3.

         "IND" shall mean an Investigational New Drug Application filed with the
United States Food and Drug  Administration,  or the  equivalent  application or
filing  necessary  to commence  human  clinical  trials in another  country,  as
applicable.

         "License Agreement" shall mean the agreement, substantially in the form
attached to this  Agreement as Exhibit B,  pursuant to which SUGEN will grant to
Allergan an exclusive,  world-wide,  royalty-bearing,  sublicensable  license to
make, have made and develop Drug


                                       3.

<PAGE>

Candidates  and/or Back-Up  Compounds for use in the Licensed Field and to make,
have  made,  use,  sell and  offer  for sale  approved  pharmaceutical  products
containing a Drug Candidate or Back-Up Compound.

         "Licensed  Field" shall mean the discovery,  development,  manufacture,
use,  marketing  and sale of drugs for the treatment or prevention of ophthalmic
diseases.

         "NDA" shall mean a New Drug  Application  filed with the United  States
Food and Drug Administration,  or the equivalent community  application filed in
the  European  Union,  or  the  equivalent   application  filed  as  a  national
application in Japan, the United Kingdom, France, Germany, Spain or Italy.

         "Regulatory Approval" shall mean any and all approvals (including price
and reimbursement approvals), licenses,  registrations, or authorizations of any
country, federal, state or local regulatory agency, department,  bureau or other
government entity that is necessary for the manufacture,  use, storage,  import,
transport and/or sale of a pharmaceutical product containing a Drug Candidate or
Back-Up Compound in a country.

         "Research  Management  Committee"  or "RMC"  shall  mean the  committee
formed pursuant to Section 2.2.

         "Research  Plan" shall mean the plan for  conducting the research under
the Collaboration, as amended from time to time by the RMC, which plan including
all amendments shall be attached to the Agreement as Exhibit E.

         "Research  Term" shall mean the three (3) years following the Effective
Date or, subject to negotiation  and agreement by the parties of terms therefor,
such longer period as the parties may agree.

         "Restricted Compounds" shall have the meaning assigned to it in Section
4.4.

         "SUGEN  Know-How"  shall  mean,  to the extent  useful in the  Licensed
Field,  tangible or intangible know-how,  trade secrets,  inventions (whether or
not patentable),  data, preclinical and clinical results, physical,  chemical or
biological material, and other information that SUGEN owns, controls or to which
it has a license (with the right to sublicense)  on the Effective  Date, and any
replication or any part of such information or material.

         "SUGEN  Library" shall mean the collection of synthetic  small molecule
and  natural  product  extract  compounds  (a)  that  are  owned by SUGEN on the
Effective Date or at any time during the Research Term, or (b) as to which SUGEN
has access and the right to sublicense from third parties.

         "SUGEN Patents" shall mean, to the extent useful in the Licensed Field,
all foreign and domestic:  (a) patents issued existing as of the Effective Date;
and (b)  patents  issuing  from patent  applications  that are pending as of the
Effective Date (including provisionals, divisionals,


                                       4.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

continuations  and   continuations-in-part   of  such  applications);   and  (c)
substitutions,   extensions,   reissues,  renewals  and  inventors  certificates
relating  to the  foregoing  patents,  which  SUGEN owns or controls or to which
SUGEN has a license (with the right to sublicense). SUGEN Patents existing as of
the  Effective  Date  include the patents and  applications  listed in Exhibit C
attached hereto.

         "SUGEN  Technology" shall mean the SUGEN Patents,  SUGEN Know-How,  the
SUGEN  Library  and, to the extent  SUGEN is free to grant  licenses  hereunder,
patents or know-how owned or controlled by SUGEN covering compounds in the SUGEN
Library,  methods  of use or  biological  assays  to the  extent  useful  in the
Licensed Field and acquired after the Effective Date.

         "Target Assays" shall have the meaning assigned to it in Section 4.1.

         "Term of the Agreement"  shall have the meaning assigned to such phrase
in Article 10.

         "Validated Target" shall mean a signal  transduction  target,  selected
from  the   group  of   tyrosine   kinases   and   tyrosine   phosphatases   and
serine-threonine  kinases,  that has been  determined by the RMC to be [       ]
where  inhibition  of  target  function  in  in vitro and in vivo models lead to
effective inhibition of pathophysiology.

2.       SCOPE AND GOVERNANCE

         2.1 Scope Of The  Collaboration.  The parties hereby agree to establish
and conduct,  during the Research Term, a collaborative  research program in the
Collaboration  Field.  The initial  Research Plan for  conducting  such research
program is  attached  hereto as  Exhibit  E. The  parties  will  collaborate  in
identifying and validating  signal  transduction  targets,  developing and using
screens based on such targets to identify,  discover  and/or  synthesize  Active
Compounds, and performing such preclinical studies as are necessary in order for
Allergan to select Drug Candidates for clinical  development into pharmaceutical
products.

         2.2 Research Management  Committee.  Promptly after the Effective Date,
the parties will form a Research Management Committee ("RMC") comprised of [   ]
representatives  of each of SUGEN and  Allergan.  One member of the RMC shall be
selected to act as the chairperson of the RMC, with each chairperson  acting for
a term of twelve (12) months.  The chairperson shall be selected  alternately by
Allergan and SUGEN, and Allergan shall designate the first chairperson.  The RMC
shall  determine  the  specific  goals for the  Collaboration,  shall manage the
ongoing   research   and   preclinical   investigations   conducted   under  the
Collaboration,  and will  monitor the  progress  and  results of such work.  All
decisions of the RMC shall be unanimous. The RMC shall meet on a quarterly basis
or at such other  frequency as the RMC agrees.  The parties shall agree upon the
time and place of meetings, substitutions and qualifications of RMC members, and
other  similar  matters.  Within  thirty (30) days after each  meeting,  the RMC
chairperson  will  provide  the parties  with a written  report  describing,  in
reasonable detail, the status of the Collaboration, a summary of the results and
progress to


                                       5.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

date, the issues requiring  resolution,  and the agreed resolution of previously
reported issues. A reasonable  number of additional  representatives  of a Party
may attend meetings of the RMC in a non-voting capacity.

         2.3 Research  Management  Committee  Functions And Powers. The Research
Management  Committee shall encourage and facilitate ongoing cooperation between
the parties,  establish, update and review the Research Plan and other plans for
accomplishing the Collaboration goals,  allocate tasks and coordinate activities
required to perform the Collaboration, monitor progress of the Collaboration and
the  parties'  diligence  in  carrying  out their  responsibilities  thereunder,
oversee the conduct of all patent  matters,  and carry out the other  duties and
responsibilities  described for it in this Agreement. In addition, the RMC shall
establish  criteria  for and  designate  Validated  Targets  under  Section 3.5,
designate the activity  levels in Target Assays that should be demonstrated by a
particular  compound screened in the Target Assay for such compound to be deemed
an Active Compound pursuant to Section 4.2(c), establish additional criteria, if
needed, for selecting Back-Up Compounds,  and review and approve the designation
of Back-Up Compounds under Section 4.7.

         2.4 Information And Reports.  Except as otherwise provided, the parties
will  make  available  and  disclose  to one  another  all  results  of the work
conducted  pursuant to the  Collaboration  prior to and in  preparation  for RMC
meetings, in the form and format to be designated by the RMC.

         2.5 RMC Dispute  Resolution.  If the RMC is unable to decide or resolve
an  issue  unanimously,  the  issue  shall be  referred  to the  Executive  Vice
President of Product  Development  of SUGEN and the Corporate  Vice President of
Science and  Technology  of Allergan,  who shall not be members of the RMC. Such
officers of the parties will meet  promptly  thereafter  and shall  negotiate in
good faith to resolve such issue. If they cannot resolve the issue within thirty
(30) days of  commencing  such  negotiations,  the issue  shall be  resolved  as
provided in Section 12.3.

3.       TARGET RESEARCH AND VALIDATION

         3.1 Testing and Validation of [           ] Target in Allergan  Models.
Promptly  after the  Effective  Date,  SUGEN shall  provide to the RMC a list of
compounds  from the SUGEN Library that represent  lead  structures  with varying
specificities  in SUGEN  assays.  Such list shall  provide  the  structures  and
properties of such compounds. The RMC shall select up to [      ] such compounds
to test in Allergan's ocular models.  SUGEN shall provide Allergan with at least
[                                      ] of each such selected compound based on
activity levels supporting  dosing of [                ] per day, solely for the
purpose of testing  hereunder.  Allergan shall test such compounds in Allergan's
ocular disease models in accordance with the Research Plan, to evaluate  SUGEN's
[               ] compounds for efficacy, and to develop, where appropriate,  an
[                 ]. Allergan understands  that such  SUGEN  compounds  provided
under this Section 3.1 may constitute  Excluded Compounds that are not available
for selection as Active Compounds under Section 4.2(c).


                                       6.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         3.2  Transfer  of  SUGEN  Technology.  Commencing  promptly  after  the
Effective  Date,  and from  time to time  thereafter,  SUGEN  will  transfer  to
Allergan such of the SUGEN Patents and SUGEN Know-How as is reasonably necessary
to enable Allergan to perform the Collaboration research hereunder in accordance
with the Research  Plan.  During the Term of the  Agreement,  SUGEN will provide
Allergan with reasonable  technical assistance relating to the use of such SUGEN
Know-How  and the  practice of such SUGEN  Patents in the  Collaboration  Field,
solely to the extent permitted under the licenses granted to Allergan herein. In
addition,  SUGEN will  provide to  Allergan,  prior to Allergan  commencing  the
testing  under  Section  3.1,  the results of SUGEN's  prior  screening of SUGEN
compounds in SUGEN's [           ] assays, with  respect to a reasonable  number
of compounds that demonstrated  significant  activity in such assays,  including
those compounds on the list provided by SUGEN to the RMC.

         3.3  Transfer of Allergan  Technology.  Commencing  promptly  after the
Effective  Date,  Allergan  will  transfer  to SUGEN on an  ongoing  basis  such
reasonable quantities of the Allergan Biomaterials as are needed to enable SUGEN
to perform the Collaboration  research in accordance with the Research Plan, and
shall disclose to SUGEN such of the Allergan  Know- How and Allergan  Patents as
is reasonably  necessary to enable SUGEN to perform the  Collaboration  research
hereunder  in  accordance  with the  Research  Plan.  During the  Collaboration,
Allergan will provide SUGEN with reasonable technical assistance relating to the
use of such  Allergan  Know-How and the practice of the Allergan  Patents in the
Collaboration  Field,  solely to the extent permitted under the licenses granted
to SUGEN herein.

         3.4 Ocular  Target  Identification.  SUGEN  shall  perform  research in
accordance  with  the  Research  Plan on the  Allergan  Biomaterials,  including
without  limitation  an  [
           ] in such Allergan  Biomaterials,  utilizing the SUGEN Technology and
Allergan  Technology as needed.  SUGEN shall report the results of such research
promptly to the RMC.  Allergan  shall  cooperate  with SUGEN in performing  such
research and target identification activity, as provided in the Research Plan.

         3.5  Target   Validation.   Following  the   identification  of  signal
transduction targets as specified in Section 3.4, the parties will cooperate and
work to validate such identified  targets as set forth in the Research Plan. The
parties will seek to establish in in vitro and in vivo models whether [

                              ]  If such activity can be demonstrated,  based on
criteria  established  by the RMC, the target will generally be considered to be
validated,  although the RMC shall determine,  in good faith, whether the target
in question is deemed a Validated  Target for purposes of this  Agreement.  Upon
the  identification of a Validated Target, the parties shall proceed as provided
in Article 4 to develop Target Assays based on such Validated  Target, to screen
appropriate  compounds  from the SUGEN  Library and other  compounds  reasonably
submitted by Allergan for screening,  if any,  against such assays,  to identify
Active   Compounds,   and  to  select  certain  Active   Compounds  for  further
investigation hereunder.



                                       7.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

4.       COMPOUND SCREENING AND SELECTION

         4.1 Assay  Development.  Upon the  selection  by the RMC of a  specific
signal  transduction  target as a Validated  Target,  SUGEN will use  reasonable
efforts in  accordance  with the Research  Plan to develop [      ] assays based
upon  such Validated  Target (the "Target  Assays").  It  is understood  that as
of the  Effective  Date,  SUGEN has already  developed  certain  assays based on
the [         ] target,  which  assays  shall be  deemed  Target  Assays  if the
[        ] target is determined to be a Validated Target. All such Target Assays
will be optimized for efficient screening of the compounds to determine [
                                     ] of compounds, in order to identify Active
Compounds.  During the  Research  Term,  SUGEN  shall  continue  to develop  and
improve the Target  Assays.  Allergan shall  cooperate  with SUGEN as reasonable
in developing  such Target Assays.

         4.2      Screening To Identify Active Compounds.

                  (a) Compounds for Screening.  During the Research Term,  SUGEN
will make the  compounds  in the  SUGEN  Library  (but  excluding  the  Excluded
Compounds)  available for screening in the Target Assays on a blinded basis. The
RMC may  also  select  for  screening  appropriate  Derivative  Compounds  made,
identified  or  acquired  during  the  Research  Term and  compounds  reasonably
proposed for  screening by  Allergan.  In addition,  the RMC may agree to obtain
from  third  parties  rights to screen  compounds  owned or  controlled  by such
parties;  provided,  however, that if there would be any amounts payable to such
third party for screening  such compounds or making,  using or selling  products
containing  such  compounds,  no such third  party  compounds  will be  screened
without the consent of both parties.

                  (b) Screening.  SUGEN shall use reasonable  efforts to conduct
the screening in the  appropriate  Target Assays of all compounds made available
by SUGEN or selected for screening under Section 4.2(a),  in accordance with the
Research Plan. The primary goal of the screening is to determine the activity of
such selected compounds to identify Active Compounds. If so directed by the RMC,
SUGEN shall also use reasonable efforts to obtain additional data from screening
of compounds relating to [        ] of compounds.  In addition to the foregoing,
SUGEN has already  screened  numerous  compounds  in the  [        ]  assays and
identified certain compounds from the SUGEN Library as active in such assays. If
the [        ] target is a Validated Target, SUGEN will provide the RMC with the
results of such screening which have not previously been provided.

                  (c)   Identification  of  Active  Compounds.   Promptly  after
completing  the screening of a batch of compounds  under this Section 4.2 in the
appropriate  Target  Assays,  SUGEN will  provide to the RMC the results of such
screening.  The RMC will review such Target Assay results promptly after receipt
and  will  determine  which of the  screened  compounds  meet  the  requirements
established by the RMC for identification as Active Compounds.  Upon identifying
Active  Compounds,  the RMC shall add such  compounds  to the list of all Active
Compounds,  which shall be  maintained by the RMC, and shall forward the updated
list to each party.  SUGEN will promptly  provide to the RMC any  information in
SUGEN's  possession  regarding the chemical  structure and  properties of Active
Compounds.


                                       8.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         4.3 Further  Investigation  on Active  Compounds.  From time to time as
appropriate  during the  Research  Term,  with the goal of promptly  identifying
appropriate   Active  Compounds  for  preclinical  work  under  Section  4.4  in
accordance with the Research Plan, the RMC will select specific Active Compounds
that appear the most  promising in the Licensed  Field for testing in Allergan's
[             ] models and/or in such other tests or  investigations  as the RMC
deems  appropriate.  Promptly after such  selection,  Allergan will conduct such
[             ] model or other  appropriate  testing  required by the RMC on the
selected  Active   Compounds.   SUGEN  shall  assist  the  RMC  in  making  such
determination,  at its request,  by performing on selected Active Compounds,  as
appropriate, further specificity determination, in vitro and in vivo potency and
safety evaluation,  and initial in vivo assessment,  as provided in the Research
Plan.  Allergan and SUGEN shall  promptly  provide to the RMC the results of all
work either party performs pursuant to this Section 4.3.

         4.4  Selection  of  Leads  for  Preclinical  Investigation.   For  each
Validated Target, Allergan shall select and the RMC shall approve and prioritize
up to [     ] Active  Compounds with activity against such Validated Target that
are most promising for  preclinical  investigation  by Allergan.  At the time of
such  approval of selected  compounds,  such  compounds  shall be  designated as
"Restricted Compounds,"  provided  that  such compounds have not been previously
designated  as  Excluded  Compounds  under  Section  4.10.  From  time  to  time
thereafter  the RMC may designate  additional  Active  Compounds as  "Restricted
Compounds",  or  remove  such  designation  from  previously  designated  Active
Compounds, so long as the total number of such Restricted Compounds with respect
to a particular Validated Target shall not exceed [
     ] at any time.  Allergan  shall use reasonable  efforts to conduct,  at its
expense,  all preclinical  testing and investigations  necessary for Allergan to
select  appropriate Active Compounds to designate as Drug Candidates for further
development.  Such further  development  may include,  at Allergan's  reasonable
discretion,  medicinal  chemistry  to  optimize  lead  compounds,  selection  or
synthesis of  Derivative  Compounds,  GLP Tox studies,  formulation  and process
development,  animal testing and other  preclinical  pharmaceutical  development
necessary  to  prepare  and file an IND.  Except as  provided  in  Section  3.1,
Allergan will be responsible  for providing at its own expense the supply of all
Drug  Candidates and Back-Up  Compounds  necessary for  preclinical and clinical
development  under  Sections  4.3  and 4.4  worldwide.  Allergan  shall  provide
promptly to the RMC the results of all work it performs pursuant to this Section
4.4.  Allergan shall use reasonable  efforts to conduct such  investigations  in
order to  select a Drug  Candidate  as soon as  practicable.  From the date upon
which each Restricted Compound is designated  hereunder  until  the date that is
[       ] months following such date of designation, but not later than [      ]
months after the end of the Research Term,  SUGEN  will not grant any license to
a third party under its interest in the  Restricted  Compound or  designate such
compound as an Excluded Compound.  However,  such [        ] month period may be
extended with respect to a particular  Restricted Compound by an amount of time,
not to exceed in any event [            ],  equivalent  to the amount of time in
excess of [           ] that was required by Allergan  to obtain  supply of such
Restricted  Compound  as  necessary  for Allergan to conduct testing hereunder.

         4.5  Selection  of Drug  Candidates.  With  respect  to each  Validated
Target,  Allergan shall have the right to select, by written notice to SUGEN and
the RMC, an Active Compound


                                       9.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

that is active in the Target  Assays for such target as the Drug  Candidate  for
clinical  development.  Allergan shall also designate the Back-Up Compounds with
respect to such  specified  Drug  Candidate,  as provided in Section  4.7.  Upon
selection of such Drug  Candidate and Back-Up  Compounds,  Allergan shall have a
period of [    ] days after the date of such notice to conduct an  investigation
to determine whether there exist  any  third  party  patent  rights  that may be
infringed by the  manufacture,  use or sale of such selected Drug Candidate,  or
whether  patent  protection can be obtained on such Drug  Candidate.  If in such
period Allergan reasonably  determines that there is a risk of infringement of a
third  party's  patent  rights  by the  manufacture,  use or sale  of such  Drug
Candidate,  or that valid patents will not be obtained which cover such selected
Drug  Candidate,  Allergan may by written  notice to SUGEN and the RMC delivered
prior to the end of such period withdraw such selection and such Active Compound
shall no longer be a Drug Candidate.  Allergan shall use commercially reasonable
efforts to select a Drug Candidate  active with respect to each Validated Target
prior to the end of the Research  Term.  Such  commercial  reasonableness  shall
include  consideration  of  all  Collaboration  activities  being  conducted  by
Allergan  hereunder.  Promptly after the first selection of a Drug Candidate and
Back-Up Compounds therefor  hereunder,  the parties shall enter into the License
Agreement with respect to the Drug Candidate and the Back-Up Compounds therefor.
The License Agreement shall be amended to identify any additional Drug Candidate
and Back-Up Compounds selected for any other Validated Target as permitted under
this  Section  4.5,  and to reflect any  substitution  of a Drug  Candidate  and
Back-Up Compound(s) as permitted in Sections 4.6 and 4.7.

         4.6 Substitution of Drug Candidate.  In the event that, during the Term
of the Agreement,  Allergan determines, based on its good faith and commercially
reasonable judgment,  that neither a Drug Candidate designated under Section 4.5
nor any of its Back-Up  Compounds can be demonstrated with reasonable effort and
expense to be safe and effective in the Licensed  Field,  then Allergan may give
SUGEN  written  notice,  prior  to the end of such  period,  that it  elects  to
relinquish all rights to such Drug Candidates and Back-Up  Compounds.  Upon such
notice,  all such compounds shall lose their  designation as Drug Candidates and
Back-Up  Compounds  and shall no longer be  subject  to the  License  Agreement.
Promptly after such notice, but in any event prior to the end of the Term of the
Agreement,  Allergan  may select from the Active  Compounds,  by giving  written
notice to SUGEN and the RMC, a substitute  Drug  Candidate and up to [         ]
Back-Up Compounds  for such Drug  Candidate;  provided,  however,  that Allergan
may not select as  such Drug  Candidate  any  Excluded  Compound.  With  respect
to such designated  substitute  Drug  Candidate,  Allergan  shall  have the same
[           ] day period of intellectual  property review as provided in Section
4.5 above.  After such period,  provided that  Allergan has not  withdrawn  such
designation  during the period, the parties shall amend the License Agreement to
identify such  newly-designated  Drug Candidate,  and the Back-Up Compounds that
are designated under Section 4.7 with respect to such new Drug Candidate.

         4.7   Designation  of  Back-Up   Compounds.   Promptly  after  Allergan
designates a Drug  Candidate as provided in Section 4.5 or 4.6,  Allergan  shall
designate in writing to the RMC a set of up to [         ] Active Compounds (but
excluding any Excluded  Compound) that are isomers,  analogs or homologs of such
Drug  Candidate  to  be  the  designated  back-up  compounds  thereto  ("Back-Up
Compounds"). The RMC shall review such designation to assure, using


                                       10.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

reasonable  discretion,  that such designated compounds are isomers,  analogs or
homologs of the designated  Drug Candidate and that such Back-Up  Compounds meet
any  additional  criteria  that may be  established  by the RMC for selection as
Back-Up Compounds. From time to time during the Term of the Agreement,  Allergan
may substitute,  for an existing  Back-Up  Compound within such set, a different
Active Compound (but excluding any Excluded Compounds) that is an isomer, analog
or homolog of the relevant Drug Candidate. Allergan may make [            ] such
substitutions  with respect to a particular set of Back-Up  Compounds during the
Research Term. Any such substitutions  which Allergan proposes to make after the
Research  Term are  subject to SUGEN's  approval,  which  approval  shall not be
unreasonably withheld.

         4.8  Development of Drug  Candidates.  As described in Article 3 of the
License  Agreement,  Allergan shall have the sole  responsibility for conducting
clinical development of Drug Candidates and/or Back-Up Compounds,  with the goal
of obtaining  Regulatory  Approval of pharmaceutical  products containing a Drug
Candidate or Back-Up Compound. Once every [      ], Allergan shall provide SUGEN
a written report  summarizing the results and progress of Allergan's  efforts on
the Drug Candidates and Back-Up Compounds,  including preclinical investigations
and clinical trials. In addition, at least every [          ] Allergan will meet
with  SUGEN to discuss  such  results  and  efforts,  and shall give  reasonable
consideration to any comments or suggestions from SUGEN.

         4.9  Product  Development  By SUGEN.  Subject  to  Section  5.4 and the
limitations in this Section, SUGEN shall have the right, but not the obligation,
to  develop,  either  alone or with  others,  any  Active  Compounds  (excluding
compounds  owned  solely by  Allergan).  For so long as any Active  Compound  is
designated as a Drug  Candidate or a Back-Up  Compound,  SUGEN shall not license
such Drug Candidate or Back-Up  Compound  therefor to any Third Party, and SUGEN
shall not itself  develop such  compound  outside the  Collaboration,  provided,
however, that SUGEN shall retain the right to use such Drug Candidate or Back-Up
Compound solely for internal research purposes.

         4.10 Excluded  Compounds.  An "Excluded Compound" shall be any compound
in the SUGEN Library that meets one of the following criteria:

                  (a) the compound is listed on Exhibit D attached  hereto as of
the Effective Date;

                  (b) the  compound is selected by a corporate  partner of SUGEN
as a lead candidate for preclinical and clinical development, prior to selection
by Allergan of such compound as a Drug Candidate or Back-up Compound,  and based
on such selection the corporate  partner makes,  within a reasonable  time after
the  selection,  a  significant  economic  payment  to SUGEN and  commits to use
diligence in such  efforts,  at least  comparable  to the economic and diligence
commitments of Allergan  hereunder and under the License Agreement when Allergan
selects a Drug Candidate,  unless such compound at the time of such selection by
the corporate partner is designated as a Restricted Compound;



                                       11.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                  (c) the compound is a member of a set of up to [   ] compounds
that are isomers,  analogs or homologs of a compound  that meets the criteria of
subsection  (b) above,  which set of compounds  are  designated  by the relevant
corporate  partner as back-up compounds to such compound selected as provided in
subsection (b);

                  (d) the compound is selected by SUGEN as a lead  candidate for
preclinical  and  clinical  development,  prior to selection by Allergan of such
compound  as a Drug  Candidate  or  Back-up  Compound,  and  SUGEN  commits  and
continues  to  expend  a  significant   amount  of  resources  on  the  diligent
preclinical and clinical  development of such compound (or back-ups  selected as
provided  in  subsection  (e) below),  unless such  compound at the time of such
selection by SUGEN is designated as a Restricted Compound;

                  (e) the compound is a member of a set of up to [   ] compounds
that are isomers,  analogs or homologs of a compound  that meets the criteria of
subsection (d) above,  which set of compounds are designated by SUGEN as back-up
compounds to such compound  selected by SUGEN as provided under  subsection (d);
or

                  (f) SUGEN has granted an exclusive license to the compound for
commercialization  purposes to Zeneca or to Asta  Medica  under the terms of the
applicable  collaboration  agreement between SUGEN and such corporate partner as
in effect on the Effective Date, unless such compound is at such time designated
as a Restricted Compound, a Drug Candidate, or Back-Up Compound.

5.       LICENSE GRANTS; EXCLUSIVITY

         5.1      License Grants For Collaborative Research.

                  (a) Grant by SUGEN.  SUGEN hereby  grants to Allergan,  during
the  Term  of  the  Agreement,  a  nonexclusive,  worldwide,   non-transferable,
royalty-free  license  under the SUGEN  Technology  and SUGEN's  interest in the
Collaboration Technology,  subject to the terms of this Agreement, solely to the
extent necessary or appropriate to carry out Allergan's research and preclinical
development responsibilities under the Collaboration.

                  (b) Grant by Allergan. Allergan hereby grants to SUGEN, during
the  Term  of  the  Agreement,  a  nonexclusive,  worldwide,   non-transferable,
royalty-free  license under the Allergan  Technology and Allergan's  interest in
the Collaboration Technology,  subject to the terms of this Agreement, solely to
the  extent   necessary   or   appropriate   to  carry  out   SUGEN's   research
responsibilities under the Collaboration.

         5.2 Execution of Commercial License Agreement. Promptly after selection
of the first Drug  Candidate,  but in any event prior to the filing of an IND by
Allergan  for such  compound,  SUGEN and  Allergan  shall enter into the License
Agreement with respect to such Drug Candidate and Back-Up Compounds therefor for
development in the Field (as defined in the License  Agreement).  Each such Drug
Candidate  and  Back-Up  Compound  shall be listed in an exhibit to the  License
Agreement, which exhibit shall be amended from time to time as


                                       12.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

necessary  to  maintain  a current  list of such  Drug  Candidates  and  Back-Up
Compounds selected for development.

         5.3 Diligence Obligations;  Grant Back. If Allergan does not enter into
a License  Agreement  with SUGEN with  respect to a Drug  Candidate  and Back-Up
Compounds  therefor prior to the earlier of [                                  ]
or the [      ] anniversary of the Effective Date (or such further period as the
parties  may  agree,  if any),  then,  provided  that such  failure to enter the
License Agreement in such time frame was not directly caused by SUGEN's material
breach of its obligations under the Agreement, the Agreement shall terminate and
the parties shall enter into a license  agreement under which Allergan grants to
SUGEN a fully paid, exclusive,  worldwide license, with the right to sublicense,
under all Allergan's  interest in the Collaboration  Technology to make, use and
sell Active Compounds (excluding any compounds owned solely by Allergan) for use
within the  Licensed  Field  (the  "Grant-Back  License").  In  addition  to the
foregoing,  in the event  that  Allergan  does not file an IND  covering  a Drug
Candidate or Back-Up Compound by the [      ] anniversary of the Effective Date,
then,  provided  that such  failure  to file the IND in such time  frame was not
directly  caused  by  SUGEN's  material  breach  of its  obligations  under  the
Agreement,  this Agreement shall terminate, and Allergan and SUGEN will promptly
enter into the Grant-Back  License.  In the event that the Agreement  terminates
pursuant to this Section 5.3, then in addition  Allergan  covenants  that, for a
period of [    ] years after the Term of the Agreement, Allergan shall not make,
use or sell any Active  Compounds  (excluding  Active  Compounds owned solely by
Allergan)  for use in the Licensed  Field,  and shall not make,  use or sell any
Active  Compounds  owned  solely by Allergan  for use in treating or  preventing
human ophthalmic  neovascular  disease.  SUGEN agrees that in the event Allergan
fails to enter into the License  Agreement with SUGEN or to file an IND covering
a Drug  Candidate  in such  time  period  as  provided  above  for  any  reason,
termination of this Agreement in respect of such failure,  the execution of such
Grant-Back  License and the granting of the above  covenant by Allergan shall be
SUGEN's sole and exclusive remedies for such failure.

         5.4      Exclusivity.

                  (a) SUGEN acknowledges and agrees that it will not collaborate
with, or grant  licenses under its interest in the  Collaboration  Technology or
the Active  Compounds to, third  parties,  or conduct  research,  development or
commercialization  except pursuant to this Agreement and the License  Agreement:
(i) during the Research Term in the [        ], (ii) after the Research Term and
until  expiration of the Term of the  Agreement,  as to the use of any Validated
Target for the discovery, identification,  development, and/or commercialization
of products useful in the [     ], and (iii) after the Term of Agreement,  as to
the use of any Validated Target for the discovery,  identification, development,
and/or commercialization  of  products  useful in the [   ] (as  defined  in the
License Agreement) pursuant to the License Agreement.



                                       13.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                  (b)  Allergan   acknowledges  and  agrees  that  it  will  not
collaborate  with,  or  grant  licenses  under  its  interest  in  Collaboration
Technology or the Active Compounds to, any third parties,  or conduct  research,
development  or  commercialization  except  pursuant to this  Agreement  and the
License Agreement: (i) during the Term of Agreement in the [
      ], and (ii) during the term of the License  Agreement  with respect to the
use of any  Validated  Target for the  discovery,  identification,  development,
and/or commercialization of products useful in the [    ] provided that Allergan
shall be  permitted  to  sublicense  as  permitted  in the License  Agreement or
otherwise  collaborate as necessary to commercialize  Drug Candidates or Back-Up
Compounds as contemplated herein and under the License Agreement.

         5.5      License Covenants. Allergan covenants that, for the  longer of
the term of the License Agreement or the Term of the Agreement plus [          ]
neither Allergan, nor any of its Affiliates,  shall develop or commercialize any
Active Compounds or any Derivative Compound thereof for use in the [
                                                                               ]
except  pursuant  to the  terms of this  Agreement  and the  License  Agreement.
Allergan further covenants that, for the Term of the Agreement plus [  ] neither
Allergan, nor any of its Affiliates,  shall prepare any derivatives,  analogs or
other chemical modifications of the Active Compounds in the SUGEN Library except
as permitted under the terms of this Agreement,  but excluding any compounds (i)
owned by Allergan as of the Effective  Date,  (ii) in the public domain or known
to Allergan prior to disclosure of such Active Compound by SUGEN to Allergan, or
(iii)  independently  developed by Allergan without use of any SUGEN Technology,
as demonstrated by Allergan's written documents.  Allergan covenants that in any
sublicense  agreement  entered  into by  Allergan or its  Affiliate  that grants
rights  under the rights  granted by SUGEN in the  License  Agreement,  Allergan
shall  impose  on such  sublicensee  the same  restrictions  as are  imposed  on
Allergan and its Affiliates in this Section 5.5.

6.       FEES AND PAYMENTS

         6.1      Initial Research Payment.  [                                 ]
Allergan  shall  pay SUGEN an  initial  research  payment  of $2.0  million  for
research efforts in the Collaboration Field prior to the Effective Date.

         6.2  Research  Funding.  Allergan  agrees to pay SUGEN,  on a quarterly
basis in advance,  payable no later than the [   ] day of the  quarter,  amounts
pursuant  to the  research  budget  established  by the RMC to  support  SUGEN's
research and screening efforts under the  Collaboration.  Such amounts shall not
exceed a total of [          ] on an annualized basis prior to the date when the
parties  have  identified a Validated  Target.  Commencing in the first calendar
quarter  after the  first  designation  of a  Validated  Target by the RMC,  the
funding provided by Allergan shall equal on an annualized basis [     ] per year
for the balance of the Research  Term,  subject to SUGEN  providing the RMC, and
the RMC  approving,  a workplan that  supports such funding.  The first and last
quarter's  payments hereunder shall be pro rated, with the first quarter payment
due [     ] days after the Effective Date.


                                       14.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         6.3 Milestone Payments To SUGEN. With respect to Validated Targets, and
all Drug  Candidates  with activity in the Target Assays based on such Validated
Targets,  Allergan will pay to SUGEN the milestone payment in the amounts listed
below, within [    ] business days after the occurrence of the following events:

- --------------------------------------------------------------------------------
MILESTONE EVENT                                            AMOUNT OF PAYMENT
- --------------------------------------------------------------------------------
(1)    [                                           ]        [       ]
- --------------------------------------------------------------------------------
(2)    [                                                    [       ]
       
       
                           ]
- --------------------------------------------------------------------------------
(3)    [                                                    [       ]
      
       
               ]
- --------------------------------------------------------------------------------
(4)    [                                                    [       ]
       
                 ]
- --------------------------------------------------------------------------------
(5)    [                                                    [       ]
                                    ]
- --------------------------------------------------------------------------------
(6)    [                                                     [       ]
                                          ]
- --------------------------------------------------------------------------------

         The  milestone  payments  for  milestone  [     ] are payable [
                                                                               ]
With  respect to a  particular  Validated  Target,  the  milestone  payments for
milestones  [     ]  are  payable the [                               ]  occurs;
provided,  however, that if there is approval of an NDA for a product containing
a Drug Candidate or Back-Up Compound thereof,  and thereafter  Allergan [
                                                      ]  thereof,  then Allergan
will pay SUGEN for  milestones  [     ]  with  respect  to [
                             ] thereof within [     ] business days after filing
an NDA on such different Drug Candidate or Back-Up Compound  thereof,  and shall
pay SUGEN for milestone  [     ] with respect to [
        ] thereof, if it occurs.

         In the  event  that,  with  respect  to  the  first  Validated  Target,
milestones [     ] all occur in 1998, then Allergan may [
                    ]

         As provided in Section 4.3 of the License Agreement, Allergan will have
certain rights to credit against  royalties  otherwise due SUGEN an amount equal
to [     ] of the sum of


                                       15.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

all milestone payments it has paid to SUGEN hereunder with respect to milestones
[     ] with respect to that Drug Candidate or Back-Up Compound.

         6.4      Equity Investments.

                  (a)  Pursuant  to the  terms of the Stock  Purchase  Agreement
between the parties,  Allergan is agreeing to purchase from SUGEN,  and SUGEN is
agreeing to sell and issue,  $4.0 million in SUGEN common  stock,  at a purchase
price of $20.88 per share.

                  (b)  Pursuant  to the terms of the Stock  Purchase  Agreement,
Allergan may purchase stock of SUGEN  equivalent to $3.0 million at the offering
price in the next  offering;  however,  Allergan shall be under no obligation to
purchase any or all of such securities.

                  (c)   Notwithstanding   anything  in  this  Agreement  to  the
contrary,  in the event Allergan fails to purchase, or make a bona fide offer to
purchase,  SUGEN securities as provided in the Stock Purchase  Agreement,  SUGEN
shall have the right to terminate this Agreement immediately upon written notice
to Allergan.

7.       INTELLECTUAL PROPERTY

         7.1 Ownership Of  Technology.  Inventorship  with respect to inventions
made pursuant to work carried out under the Collaboration shall be determined in
accordance with United States rules of  inventorship.  Except as provided below,
each party shall own solely all inventions made [          ] made hereunder. All
inventions  (the  "Compound  Inventions")  made  by or  on  behalf  of  Allergan
comprising compounds that are isomers, analogs or homologs of an Active Compound
unless such compound is (i) in the public  domain or known to Allergan  prior to
disclosure of such Active Compound by SUGEN to Allergan,  or (ii)  independently
developed by Allergan without use of the SUGEN  Technology,  as shown by written
documents of Allergan, and all intellectual property rights with respect to such
inventions, shall be [     ] subject to the cross-licenses in Section 7.6 below.
Any  assignments  necessary to accomplish  the  foregoing  are hereby  made  and
Allergan agrees to execute such further documents as may be reasonably requested
by SUGEN with respect thereto.


         7.2  Patent  Prosecution.  Allergan  Patents  and  SUGEN  Patents,  and
applications therefore, shall be prosecuted and maintained by [
                                     ] provided, however, that the parties shall
consult  with  and  consider  the  comments  of  the  RMC  with  respect  to the
prosecution of applications for [
                ]  Collaboration  Patents  for  inventions  owned  by one  party
pursuant to Section 7.1 above shall be prosecuted and maintained by the [
                        ]  Except as provided below, [                   ] shall
be responsible for filing and  prosecuting  applications  for, and  maintaining,
jointly owned Collaboration Patents, using counsel of its choice, throughout the
world.  [            ] shall reimburse [      ] for one-


                                       16.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

half of all expenses [     ] incurs for filing applications for, and maintenance
of, such  jointly-owned  Collaboration  Patents  world wide.  For  jointly-owned
Collaboration  Patents that claim inventions  relating primarily to the [
             ] shall be responsible,  at its expense subject to reimbursement as
provided below, for prosecuting applications for, and maintaining, such patents,
using counsel of its choice, throughout the world. As provided in Section 4.5 of
the License  Agreement,  if a Licensed Product is commercially sold, [     ] may
recover [     ] of its costs in prosecuting jointly-owned  Collaboration Patents
relating  primarily to the [            ] that claim such Licensed  Product.  In
the event that a party decides not to proceed with  prosecuting  an  application
for, or maintaining,  a Collaboration  Patent for which it is responsible  under
this Section 7.2, it shall give the other party  [     ] days' notice before any
relevant  deadline and  transmit  all  information  reasonable  and  appropriate
relating to such Collaboration Patent, and such other party shall have the right
to  pursue,  at its  own  expense,  prosecution  of  such  application  for,  or
maintenance  of,  such  patent,  in which  event  the party  not  pursuing  such
Collaboration  Patent shall assign all of its rights in such patent to the other
party.

         7.3  Infringement.  The License Agreement shall provide for enforcement
of the patents  licensed to Allergan  under such License  Agreement  and defense
against  third party claims of  infringement,  and such matters will be governed
thereby.  If  any  patent  infringement  matters  arise  with  respect  to  this
Agreement,  the parties will discuss in good faith the manner in which they will
proceed to address such issues.

         7.4  Trademarks.  Each party  shall  obtain,  own and  enforce  its own
trademarks with respect to its own activities.

         7.5 Disclosure Of Inventions. SUGEN and Allergan will disclose promptly
to  each  other  all  discoveries  or  inventions   made  hereunder,   including
discoveries  or  inventions  made by  consultants  or  contractors  of SUGEN and
Allergan pursuant to the Collaboration, prior to any public disclosure or filing
of patent  applications  and allowing  sufficient time for comment and review by
the other party.  Without  limiting the  foregoing,  Allergan  shall disclose to
SUGEN  promptly all compounds made by or on behalf of Allergan that are chemical
modifications of Active Compounds.  All compounds comprising Compound Inventions
shall be included within the Collaboration Technology.

         7.6 Cross-Licenses  Regarding Compound Inventions.  SUGEN hereby grants
Allergan an exclusive,  world-wide  license under SUGEN's rights in the Compound
Inventions,  and all  Collaboration  Patents claiming such Compound  Inventions,
solely for use in the Licensed Field.  Allergan hereby grants SUGEN an exclusive
option to obtain the exclusive,  world-wide  license under Allergan's  rights in
the Compound  Inventions,  and all Collaboration  Patents claiming such Compound
Inventions,  solely for use  outside  the  Licensed  Field.  Such  option may be
exercised in writing prior to the [     ]  anniversary of the end of the Term of
the  Agreement,  and such license  shall be subject to SUGEN's  agreement to pay
Allergan a commercially reasonable royalty to be negotiated in good faith by the
parties at the time SUGEN exercises such option.



                                       17.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

8.       REPRESENTATIONS AND WARRANTIES

         8.1 Representations And Warranties.  Each party represents to the other
that:

                  (a) Corporate and Partnership  Power. It is duly organized and
validly  existing  under the laws of its state or  country of  incorporation  or
formation,  and has full corporate or  partnership  power and authority to enter
into this Agreement and to carry out the provisions hereof.

                  (b) Due  Authorization.  It is duly  authorized to execute and
deliver this Agreement and to perform its obligations hereunder,  and the person
or persons executing this Agreement on its behalf has been duly authorized to do
so by all requisite corporate or partnership action.

                  (c) Binding Agreement.  This Agreement is legally binding upon
it,  enforceable  in  accordance  with its terms.  The  execution,  delivery and
performance  of this  Agreement  by it does not  conflict  with  any  agreement,
instrument or understanding, oral or written, to which it is a party or by which
it may be bound,  nor  violate  any  material  law or  regulation  of any court,
governmental body or administrative or other agency having jurisdiction over it.

                  (d) Grant of Rights;  Maintenance of  Agreements.  It has not,
and will not  during  the term of this  Agreement,  grant any right to any third
party which would conflict with the rights granted to the other party hereunder.
It has (or  will  have at the  time  performance  is due)  maintained  and  will
maintain  and keep in full force and effect all  agreements  (including  license
agreements)  and filings  (including  patent  filings)  necessary to perform its
obligations hereunder.

                  (e)  Validity.  It is aware of no  action,  suit or inquiry or
investigation  instituted  by or before any court or  governmental  agency which
questions or threatens the validity of this Agreement or of any SUGEN Patent.

                  (f) Third Party  Rights.  It is aware of no third party patent
right  which  would  be  infringed  by  its  conduct  of  the  Collaboration  or
commercialization of Active Compounds as contemplated hereby.

         8.2 SUGEN Representations and Warranties. SUGEN represents and warrants
that:

                  (a) SUGEN  owns or holds  licenses  to the SUGEN  Patents  and
SUGEN  Know-How  and has  sufficient  rights and power to grant the  licenses to
Allergan which it purports to grant herein.

                  (b)      [
]



                                       18.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[
]
                  (c)      [



] and

         8.3 Disclaimer Concerning  Technology.  EXCEPT AS SET FORTH IN SECTIONS
8.1(f) AND 8.2 ABOVE, THE TECHNOLOGY AND INTELLECTUAL PROPERTY RIGHT PROVIDED BY
EACH PARTY HEREUNDER IS PROVIDED "AS IS" AND EACH PARTY EXPRESSLY  DISCLAIMS ANY
AND ALL WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
THE  WARRANTIES OF DESIGN,  MERCHANTABILITY,  FITNESS FOR A PARTICULAR  PURPOSE,
NONINFRINGEMENT OF THE INTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES, OR ARISING
FROM A COURSE OF DEALING,  USAGE OR TRADE  PRACTICES,  IN ALL CASES WITH RESPECT
THERETO. Without limiting the generality of the foregoing,  each party expressly
does not  warrant  (i) the  success  of any  study or test  commenced  under the
Collaboration or (ii) the safety or usefulness for any purpose of the technology
it provides hereunder.

         8.4 Disclaimer  Concerning  Library  Compounds.  EXCEPT AS SET FORTH IN
SECTIONS 8.1(f) AND 8.2 ABOVE, THE SUGEN LIBRARY COMPOUNDS ARE PROVIDED BY SUGEN
"AS IS" AND  SUGEN  EXPRESSLY  DISCLAIMS  ANY AND ALL  WARRANTIES  OF ANY  KIND,
EXPRESS OR IMPLIED,  INCLUDING  WITHOUT  LIMITATION  THE  WARRANTIES  OF DESIGN,
MERCHANTABILITY,  FITNESS  FOR A  PARTICULAR  PURPOSE,  NON-INFRINGEMENT  OF THE
INTELLECTUAL  PROPERTY  RIGHTS OF THIRD  PARTIES,  OR  ARISING  FROM A COURSE OF
DEALING,  USAGE OR TRADE PRACTICES,  IN ALL CASES WITH RESPECT THERETO.  Without
limiting the generality of the foregoing,  SUGEN  expressly does not warrant (i)
that any SUGEN  Library  compound it provides  hereunder  is free from any third
party rights,  except as otherwise  provided in Sections 8.1(f) and 8.2, or (ii)
the safety or  usefulness  for any  purpose  of any SUGEN  Library  compound  it
provides hereunder.

9.       CONFIDENTIALITY; PUBLICATION

         9.1 Confidentiality.  Except to the extent expressly authorized by this
Agreement or otherwise agreed in writing by the parties, the parties agree that,
for the term of this Agreement and for five (5) years thereafter,  the receiving
party shall keep  confidential  and shall not publish or otherwise  disclose and
shall not use for any purpose  other than as provided for in this  Agreement any
Confidential  Information  furnished  to it by the other party  pursuant to this
Agreement,  unless the receiving  party can  demonstrate by competent proof that
such Confidential Information:

                  (a) was already known to the receiving party, other than under
an obligation of confidentiality, at the time of disclosure by the other party;


                                       19.

<PAGE>

                  (b) was generally available to the public or otherwise part of
the public domain at the time of its disclosure to the receiving party;

                  (c) became generally available to the public or otherwise part
of the public  domain  after its  disclosure  and other than  through any act or
omission of the receiving party in breach of this Agreements;

                  (d) was disclosed to the receiving party,  other than under an
obligation  of  confidentiality  to a third  party,  by a third party who had no
obligation to the disclosing  party not to disclose such  information to others;
or

                  (e) was independently discovered or developed by the receiving
party without the use of  Confidential  Information  belonging to the disclosing
party.

         However,  (a) and (e) shall not apply  with  respect to  inventions  of
which  ownership is transferred  pursuant to Section 7.1 above.  Such inventions
shall be deemed to be the  Confidential  Information  of the party to which they
are assigned.

         9.2  Authorized  Disclosure.   Each  party  may  disclose  Confidential
Information  belonging  to the other  party to the  extent  such  disclosure  is
reasonably necessary in the following instances:

                  (a) filing or prosecuting patents relating to Active Compounds
or Licensed Products;

                  (b) regulatory filings;

                  (c) prosecuting or defending litigation;

                  (d) complying with applicable governmental regulations;

                  (e)  conducting  pre-clinical  or  clinical  trials  of Active
Compounds or Drug Candidates; and

                  (f)   disclosure  to  Affiliates,   sublicensees,   employees,
consultants or agents who agree to be bound by similar terms of  confidentiality
and non-use at least equivalent in scope to those set forth in this Article 9.

Notwithstanding  the  foregoing,  in the  event a party  is  required  to make a
disclosure  of the  other  party's  Confidential  Information  pursuant  to this
Section 9.2, it will, except where impracticable, give reasonable advance notice
to the other party of such  disclosure  and use  efforts to secure  confidential
treatment  of such  information  at least as diligent as such party would use to
protect its own confidential  information,  but in no event less than reasonable
efforts.  In any event, the parties agree to take all reasonable action to avoid
disclosure of Confidential  Information hereunder. The parties will consult with
each other and agree on the provisions of this


                                       20.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

Agreement to be redacted in any filings made by the parties with the  Securities
and Exchange Commission or as otherwise required by law.

         9.3  Publications.  Each  party  primarily  responsible  for a proposed
publication relating to any activities conducted under the Collaboration and any
Active Compound or Licensed  Product,  whether  written or oral,  shall at least
[     ] days before presentation or submission of the proposed  publication to a
third party,  subject such  proposed  publication  to each member of the RMC for
review in  connection  with  obtaining or  preserving  patent  rights  and/or to
determine whether  confidential  information should be modified or deleted.  The
RMC shall have [     ] in which to review each proposed publication.  The review
period may be extended  for an  additional  [     ] days when the RMC provides a
reasonable  need  for  such  extension,   including,  but  not  limited  to  the
preparation and filing of pertinent patent applications.  If after [     ] days,
the other party has not provided the RMC and the  publishing  party with a valid
request for extension of the review period, such publication shall be considered
approved for submission  for  publication.  By mutual  agreement of the parties,
this period may be further  extended.  The  obligations  under this  Section 9.3
shall not apply to  publications of marketing  materials for a Licensed  Product
after  its first  commercial  sale  except  where the  proposed  publication  is
reasonably related to obtaining or preserving patent rights.

10.      TERM AND TERMINATION

         10.1 Term Of The Agreement.  This Agreement shall become effective upon
the Effective Date and continue for a term (the "Term of Agreement") of five (5)
years, or such different period if the Agreement is earlier terminated  pursuant
to Section 6.4, 10.2, 10.3 or 10.4 or is extended upon terms mutually  agreeable
to both parties

         10.2 Termination For Material  Breach.  Each party shall have the right
to terminate this Agreement after [           ] days prior written notice to the
other that the other  party has  committed a material  breach of the  Agreement,
unless the other party cures the breach  within such period of time,  or, in the
case that such breach cannot be cured within such period, the party continues to
use diligent  efforts to cure such breach  until  actually  cured.  All licenses
granted to the  non-breaching  party under Section 5.1 of this  Agreement  shall
survive such termination.

         10.3 Termination For Technical  Failure.  If after the end of the first
[      ] months of the Research Term the parties have not identified a Validated
Target,  the RMC shall meet  promptly  after  expiration  of such [     ]  month
period to  consider  whether  it is  unlikely  due to  technical  or  scientific
limitations that the parties will be able to identify a Drug Candidate under the
Collaboration.  The RMC shall  notify the parties of such  determination  within
[         ] days after the  expiration of such [     ] month period.  If the RMC
determines that identification of a Drug Candidate is unlikely,  then thereafter
Allergan will be entitled to terminate the Agreement on [         ] days written
notice  without  further  obligation,  except for any  payments  owed SUGEN that
accrued  prior to such  termination  and for any  obligations  that  survive  as
provided in Section 10.5.



                                       21.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         10.4     Termination By Allergan Without Cause. Prior to the end of the
Research Term, but not sooner than [                ] months after the Effective
Date, Allergan may terminate the Agreement without cause. Upon such termination,
(a) Allergan shall pay SUGEN an amount not to exceed [                ] required
to support SUGEN's research during the [
    ] year period  following the effective date of such termination by Allergan,
such  amount to be calculated  by [     ] but in no  event beyond the end of the
Research Term; and (b) Allergan shall grant to SUGEN the Grant- Back License and
shall  provide  the  covenant  as set  forth  in  Section  5.3,  which  shall be
Allergan's  only  obligation  to SUGEN with respect to any  termination  without
cause under this Section 10.4; provided,  however,  that the foregoing shall not
limit or constitute a waiver of any other right that SUGEN may have under law or
equity in the event of material breach of this Agreement by Allergan.

         10.5  Accrued  Rights,  Surviving  Obligations.   Termination  of  this
Agreement  shall not affect any accrued rights of either party other than as may
be provided in Section  10.2.  The terms of Sections  5.3,  5.4,  5.5,  6.3, 7.1
through 7.4 (so long as a License Agreement shall remain in effect), Section 7.5
(for so long as necessary to comply  therewith  with respect to  discoveries  or
inventions made prior to such  termination),  Sections 7.6, 9, 10 and 11 of this
Agreement  shall  survive   termination  of  this   Agreement.   Promptly  after
termination of this Agreement each party shall return or dispose of any Know-How
of the other in the accordance  with the  instructions  of the other,  including
without  limitation  any  compounds,  assays  or other  biological  or  chemical
materials.

11.      INDEMNITY

         11.1 Indemnification. Each party hereby agrees to save, defend and hold
the other party and its directors, officers, employees, and agents harmless from
and against any and all claims, suits, actions, demands,  liabilities,  expenses
and/or  loss,   including   reasonable   legal  expense  and   attorneys'   fees
(collectively, "Claims") for damage to persons or property resulting directly or
indirectly from actions in connection with the Collaboration by the indemnifying
party,  its  Affiliates,  agents or  sublicensees,  but only to the extent  such
Claims  result from the  negligence or willful  misconduct  of the  indemnifying
party or its  Affiliates,  agents or  sublicensees  and do not  result  from the
negligence of the party seeking indemnification.

         11.2 Control Of Defense.  Any entity entitled to indemnification  under
this Article shall give notice to the indemnifying  party of any Claims that may
be subject to  indemnification,  promptly after learning of such Claim,  and the
indemnifying  party  shall  assume  the  defense  of such  Claims  with  counsel
reasonably  satisfactory to the indemnified party. If such defense is assumed by
the indemnifying party with counsel so selected, the indemnifying party will not
be  subject to any  liability  for any  settlement  of such  Claims  made by the
indemnified party without its consent (but such consent will not be unreasonably
withheld or delayed),  and will not be obligated to pay the fees and expenses of
any  separate  counsel  retained by the  indemnified  party with respect to such
Claims.



                                       22.

<PAGE>


12.      GOVERNING LAW; DISPUTE RESOLUTION

         12.1 Governing Law. This Agreement shall be governed by California law,
excluding its choice of law rules.

         12.2 Legal  Compliance.  Within  thirty  days of the date  hereof,  the
parties  shall  review in good faith and  cooperate  in taking  such  actions to
ensure compliance of this Agreement with all applicable laws.

         12.3  Dispute  Resolution.  Except as provided  in Section  2.5, in the
event of any dispute,  the parties  shall refer such dispute to the CEO of SUGEN
and the CEO of Allergan  for  attempted  resolution  by good faith  negotiations
within sixty (60) days after such  referral is made.  During such period of good
faith  negotiations,  any applicable  time periods under this Agreement shall be
tolled.  In the event such  executives are unable to resolve such dispute within
such sixty  (60) day  period,  either  party may  invoke  such other  actions or
remedies as may be available to it under applicable law.

         12.4 Jurisdiction And Venue. Except as provided in Sections 2.5 or 12.3
above,  any claim or controversy  arising out of or related to this Agreement or
any breach hereof shall be  adjudicated  in the state and federal  courts having
jurisdiction  over disputes arising in the State of California,  and the parties
hereby consent to the jurisdiction and venue of such court.

13.      GENERAL PROVISIONS

         13.1 Notices.  All notices required or permitted to be given under this
Agreement  shall be in writing and shall be mailed by  registered  or  certified
mail,  Federal Express or DHL, addressed to the signatory to whom such notice is
required or  permitted  to be given and  transmitted  by facsimile to the number
indicated below. All notices shall be deemed to have been given when mailed,  as
evidenced by the postmark at the point of mailing, or faxed.

         All notices to Allergan shall be addressed as follows:

                  Vision Pharmaceuticals L.P.
                  c/o Allergan, Inc.
                  2525 Dupont Drive
                  Irvine, CA 92623
                  Attn:  Executive Vice President, Research and Development
                  Fax:  (714) 246-6987

         with a copy to:

                  Allergan, Inc.
                  2525 Dupont Drive
                  Irvine, CA 92623
                  Attn:  Allergan General Counsel
                  Fax: (714) 246-4774


                                       23.

<PAGE>




         All notices to SUGEN shall be addressed as follows:

                  SUGEN, INC.
                  515 Galveston Drive
                  Redwood City, CA 94063 4720
                  Attn: President
                  Fax: (415) 369-0741

         with a copy to:

                  Cooley Godward LLP
                  Five Palo Alto Square
                  3000 El Camino Real
                  Palo Alto, California  94306
                  Attn:  Brian C. Cunningham, Esq.
                  Fax:  (415) 857-0663

         Any party may, by written notice to the other,  designate a new address
or fax number to which  notices to the party giving the notice shall  thereafter
be mailed or faxed.

         13.2 Force  Majeure.  No party shall be liable for any delay or failure
of  performance  to the extent such delay or failure is caused by  circumstances
beyond its  reasonable  control and that by the exercise of due  diligence it is
unable to prevent, provided that the party claiming excuse uses its best efforts
to overcome the same.

         13.3 Entirety Of Agreement.  This Agreement embodies the entire,  final
and complete  agreement and  understanding  between the parties and replaces and
supersedes all prior discussions and agreements between them with respect to its
subject  matter.  No  modification  or waiver of any terms or conditions  hereof
shall be  effective  unless  made in  writing  and  signed by a duly  authorized
officer of each party.

         13.4 Non Waiver. The failure of a party in any one or more instances to
insist  upon  strict  performance  of any of the  terms and  conditions  of this
Agreement shall not constitute a waiver or relinquishment, to any extent, of the
right to  assert  or rely  upon  any such  terms  or  conditions  on any  future
occasion.

         13.5  Disclaimer Of Agency.  Neither party is, or will be deemed to be,
the legal  representative or agent of the other, nor shall either party have the
right or  authority  to assume,  create,  or incur any third party  liability or
obligation  of any kind,  express  or  implied,  against or in the name of or on
behalf of another except as expressly set forth in this Agreement.

         13.6 Severability.  If a court of competent  jurisdiction  declares any
provision of this Agreement  invalid or  unenforceable,  or if any government or
other  agency  having  jurisdiction  over  either  SUGEN or  Allergan  deems any
provision to be contrary to any laws,  then that provision  shall be severed and
the remainder of the Agreement shall continue in full force and


                                       24.

<PAGE>

effect.  To the extent  possible,  the parties  shall  revise  such  invalidated
provision in a manner that will render such  provision  valid without  impairing
the parties' original intent.

         13.7  Affiliates;  Assignment.  Except as  otherwise  provided  herein,
neither party may assign its rights or delegate its duties under this  Agreement
without the prior  written  consent of the other party,  not to be  unreasonably
withheld;  provided, however, that either party may assign this Agreement to any
of its Affiliates or to any successor by merger or sale of substantially  all of
its  business  unit to which this  Agreement  relates in a manner  such that the
assignor will remain liable and  responsible  for the performance and observance
of all its duties and  obligations  hereunder.  This Agreement  shall be binding
upon  the  successors  and  permitted  assigns  of the  parties.  Any  attempted
delegation or assignment not in accordance with this Section 13.7 shall be of no
force or effect.  Notwithstanding the foregoing provisions of this Section 13.7,
[
     ]

         13.8 Headings. The headings contained in this Agreement have been added
for convenience only and shall not be construed as limiting.

         13.9  Limitation Of Liability.  No party shall be liable to another for
indirect,  incidental,  consequential  or  special  damages,  including  but not
limited  to  lost  profits,  arising  from or  relating  to any  breach  of this
Agreement,  regardless of any notice of the possibility of such damages. Nothing
in this Section is intended to limit or restrict the  indemnification  rights or
obligations of any party.

         13.10  Counterparts.  This  Agreement  may be  executed  in one or more
counterparts,  each  of  which  shall  be an  original  and all of  which  shall
constitute together the same document.

         13.11  Public  Disclosure.  Except  for such  disclosure  as is  deemed
necessary, in the reasonable judgment of a party, to comply with applicable laws
or regulations, no announcement, news release, public statement, publication, or
presentation  relating to the existence of this Agreement,  or the terms hereof,
will be made without the other party's prior written  approval,  which  approval
shall  not be  unreasonably  withheld.  The  parties  agree  that  they will use
reasonable  efforts to  coordinate  the initial  announcement  or press  release
relating to the  existence of this  Agreement in the form attached as Exhibit F,
so  that  such  initial   announcement   or  press   release  by  each  is  made
contemporaneously.

         13.12  Guarantee.  Allergan,  Inc.  guarantees the  performance of each
obligation of Vision Pharmaceuticals,  L.P. under this Agreement, whether or not
Allergan,  Inc.  has  received  any  notice  which is to be  provided  to Vision
Pharmaceuticals, Inc. pursuant to this Agreement.




                                       25.

<PAGE>

         IN  WITNESS  WHEREOF,  the  parties  hereto  have  duly  executed  this
Agreement.

SUGEN INC.                              VISION PHARMACEUTICALS L.P.
                                        Texas limited partnership, dba Allergan,
                                        by Allergan General, Inc., its general
                                        partner



By:  /s/ Stephen Evans-Freke             By:  /s/ Francis R. Tunney
     -------------------------------          -------------------------------
Name:    Stephen Evans-Freke             Name:        Francis R. Tunney, Jr.
     -------------------------------          -------------------------------
Title:   Chairman of the Board & CEO     Title:       Secretary
     -------------------------------          -------------------------------


Guarantee of performance by:

ALLERGAN, INC.



By:
     -------------------------------
Name:
     -------------------------------
Title:
     -------------------------------



                                       26.

<PAGE>



                                    EXHIBIT A

                              ALLERGAN BIOMATERIALS



[




                                ]



 
<PAGE>



                                    EXHIBIT B

                            FORM OF LICENSE AGREEMENT




<PAGE>

                                LICENSE AGREEMENT

         THIS LICENSE AGREEMENT (the "Agreement") is made and entered into as of
_____________,  199__ (the  "Effective  Date") by and  between  SUGEN,  INC.,  a
Delaware corporation ("SUGEN"),  VISION  PHARMACEUTICALS,  L.P., a Texas Limited
Partnership  ("Allergan"),  with a  headquarters  at 2525 Dupont Drive,  Irvine,
California  90723,  and  Allergan,  Inc.,  a Delaware  corporation,  solely as a
guarantor of the  performance  under this  Agreement by Vision  Pharmaceuticals,
L.P.

                                    RECITALS

         WHEREAS, SUGEN and Allergan have entered into a Collaboration Agreement
dated as of October ___, 1996 (the "Collaboration Agreement"); and

         WHEREAS,  the parties have jointly  engaged in research,  discovery and
preclinical   investigations  on  certain  compounds   potentially   useful  for
inhibiting  neovascularization relating to ophthalmic diseases, and Allergan has
selected  certain  of such  compounds  as Drug  Candidates,  as  defined  in the
Collaboration Agreement; and

         WHEREAS, Allergan intends to file an IND with respect to one or more of
such Drug Candidates and to commence clinical  development with the intention of
obtaining  regulatory  approval  of at least  one such  compound  as a  Licensed
Product for commercialization;

         NOW, THEREFORE, in consideration of the foregoing and the covenants and
premises contained herein, the parties agree as follows:

1.   Definitions

         As  used  herein,  the  following  capitalized  terms  shall  have  the
following meanings:

         1.1  "Active   Compound"  shall  have  the  meaning   ascribed  in  the
Collaboration Agreement.

         1.2  "Advertising  and  Promotion"  means  the  promotion  of  Licensed
Products   through  any  means,   including   without   limitation,   television
advertisements,  advertisements appearing in journals, newspapers,  magazines or
other media,  including direct mail, seminars and conventions,  product samples,
promotional  literature,  visual aids, three dimensional  promotional items, and
other selling  materials,  hospital  formulary  presentations,  presentations to
state and other  governmental  formularies,  and symposia and leader development
activities.

         1.3 "Advertising and Promotion Cost" means actual direct costs incurred
for Advertising and Promotion.

                                       1.

<PAGE>

         1.4  "Affiliate"  shall  mean any  company  or  entity  controlled  by,
controlling,  or under  common  control  with a party  hereto and shall  include
without limitation any company fifty percent (50%) or more of whose voting stock
or participating profit interest is owned or controlled, directly or indirectly,
by a party,  and any company  which owns or  controls,  directly or  indirectly,
fifty percent (50%) or more of the voting stock of a party.

         1.5  "Allowable  Expenses"  shall mean,  with respect to any particular
Licensed  Product,  the sum of  Manufacturing  Costs,  Financing Cost Allowance,
Advertising and Promotion Costs,  Selling Expenses,  Third Party Contract Costs,
Third Party Royalties, Post-Marketing Study Costs.

         1.6  "Back-Up  Compounds"  shall  have  the  meaning  ascribed  in  the
Collaboration Agreement. Back-Up Compounds shall be listed on Exhibit B attached
hereto,  which  Exhibit  shall be updated and  amended  from time to time to the
extent Allergan selects  additional  Back-Up Compounds for other Drug Candidates
or substitutes new Back-Up Compounds for existing Back-Up Compounds  pursuant to
the Collaboration Agreement.

         1.7  "Collaboration  Agreement" shall mean the Collaboration  Agreement
entered into by and between SUGEN and Allergan as of October ___, 1996.

         1.8  "Collaboration  Know-How"  shall have the meaning  ascribed in the
Collaboration Agreement.

         1.9  "Collaboration  Patents"  shall have the  meaning  ascribed in the
Collaboration Agreement.

         1.10  "Collaboration  Royalties" shall mean those royalties  payable to
SUGEN for Licensed  Products under Section 4.1 of this  Agreement,  or which are
reimbursed  by Allergan to SUGEN for the payment of royalties  to Third  Parties
for sales of Licensed Products.

         1.11  "Collaboration  Technology"67  shall have the meaning ascribed in
the Collaboration Agreement.

         1.12 "Confidential  Information"67 shall mean each party's confidential
information,  inventions,  know how or data disclosed pursuant to this Agreement
or the Collaboration Agreement, including without limitation technical, business
development manufacturing,  marketing,  financial,  personnel and other business
information  and  plans,  and the  terms  of this  Agreement,  whether  in oral,
written, graphic or electronic form.

         1.13 "Development  Costs" means all direct and indirect costs allocable
to any particular Drug Candidate calculated as set forth on Exhibit C.

                                       2.

<PAGE>

         1.14  "Drug   Candidate"   shall  have  the  meaning  ascribed  in  the
Collaboration  Agreement.  Drug Candidates shall be listed on Exhibit B attached
hereto,  which  Exhibit  shall be updated and  amended  from time to time to the
extent  Allergan  selects  additional Drug  Candidates,  or substitutes new Drug
Candidates for existing Drug  Candidates,  as permitted under the  Collaboration
Agreement.

         1.15 "Field"  shall mean the  treatment  or  prevention  of  ophthalmic
diseases.

         1.16 "Financing Cost Allowance"  shall mean, with respect to Allergan's
costs  associated  with sales of Licensed  Products,  Allergan's  financing cost
allowance  calculated  using  the  prime  rate of the  Bank of  America  for the
reporting  period and the  average  investment  during  the  period in  accounts
receivable from sales of and inventories of Licensed Products.

         1.17 "IND" shall mean an  Investigational  New Drug  Application  filed
with  the  United  States  Food  and  Drug  Administration,  or  the  equivalent
application or filing  necessary to commence  human  clinical  trials in another
country, as applicable.

         1.18  "Licensed  Know-How"  shall mean all SUGEN  Know-How  and SUGEN's
interest  in  Collaboration   Know-How  that  is  necessary  or  useful  to  the
manufacture, use, sale, offer for sale or import of Licensed Products, including
without  limitation all  information  obtained from screening  activities in the
course of the work conducted under the Collaboration Agreement.

         1.19   "Licensed   Patents"  shall  mean  all  SUGEN  Patents  and  all
Collaboration  Patents that would be infringed by the  manufacture,  use,  sale,
offer for sale or import  of  Licensed  Products,  but for the  license  granted
herein,  all of which shall be listed on Exhibit A hereto,  as amended from time
to time.

         1.20 "Licensed Product" shall mean a pharmaceutical  product containing
a Drug  Candidate or a Back-Up  Compound  therefor,  which  product has received
Regulatory Approval for commercial  marketing and sale for use in the Field, and
including all formulations, line extensions, or modes of administration thereof.

         1.21  "Licensed  Technology"  shall mean the  Licensed  Patents and the
Licensed Know-How.

         1.22  "Manufacturing  Costs"  shall  mean,  with  respect  to  Licensed
Products sold during a particular quarter: (a) the actual costs of manufacturing
and packaging the Licensed Products, consisting of the cost of all raw materials
and components,  the direct labor costs associated with such  manufacturing  and
packaging,  including fully  allocated  benefits for such direct labor costs and
allocated overhead costs associated with such  manufacturing and packaging,  and
(b) costs of handling and  distribution  within  Allergan 

                                       3.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

or its Affiliates (but not including  shipping or freight charges deducted under
the Net  Sales  calculation  for  Licensed  Products),  all in  accordance  with
generally accepted accounting principles consistently applied.

         1.23 "Net Sales" shall mean,  with respect to a Licensed  Product,  the
amount  billed  for sales of such  Licensed  Product to Third  Parties  less the
following items, as allocable to such product: [



                                            ]

         1.24  "NDA"  shall  mean a New Drug  Application  filed with the United
States Food and Drug Administration,  the equivalent community application filed
in the  European  Union,  or the  equivalent  application  filed  as a  national
application in Japan, the United Kingdom, France, Germany, Spain or Italy.

         1.25 "Option Market" shall mean the countries listed in Exhibit D.

         1.26  "Post-Marketing  Study  Costs"  shall mean direct costs which are
associated with but not limited to regulatory,  medical,  product  surveillance,
and  pharmacoeconomic  studies  for a  Licensed  Product  at any time  following
Regulatory  Approval  of such  Licensed  Product  and  any  Phase  IIIb  studies
conducted prior to Regulatory Approval.

         1.27  "Profit"  shall mean,  with  respect to any  particular  Licensed
Product,  Net Sales less the  following  items,  as allocable  to such  Licensed
Product: (i) Allowable Expenses and (ii) Collaboration Royalties.

         1.28 "Profit Share  Option" shall have the meaning  ascribed in Section
5.1.

         1.29 "Regulatory  Approval" shall mean any and all approvals (including
price and reimbursement approvals),  licenses,  registrations, or authorizations
of any country, federal, state or local regulatory agency, department, bureau or
other  government  entity that is necessary for the manufacture,  use,  storage,
import, transport and/or sale of a Licensed Product in a country.

         1.30 "Selling  Expenses" shall mean allocated direct costs of the sales
force that sells a particular Licensed Product,  and including  training,  sales
bulletins and price lists and other  communications,  sales  meetings,  contract
specialty  force,  consultants,  call  reporting  and other  monitoring/tracking
costs,  district and regional sales  management,  home office  personnel who are
significantly  dedicated  to such  Licensed  Product  (such as product  manager,
advertising   promotion  manager  and  market  research  specialist)  and  other
ancillary  services,  all of the foregoing only to the extent directly allocable
to activities relating to the marketing or selling of such Licensed Product.

                                       4.

<PAGE>

         1.31  "SUGEN   Know-How"  shall  have  the  meaning   ascribed  in  the
Collaboration Agreement.

         1.32  "SUGEN   Patents"   shall  have  the  meaning   ascribed  in  the
Collaboration Agreement.

         1.33 "Third  Party" shall mean any person or entity other than Allergan
and SUGEN, and their respective Affiliates.

         1.34 "Third Party  Contract  Costs" shall mean costs charged by a Third
Party to Allergan for the performance of services related to the  manufacturing,
marketing, sale or distribution of Licensed Products.

         1.35 "Third Party  Royalties"2 means royalties payable by Allergan to a
Third Party in respect of the sale of Licensed Products.

         1.36 "Valid  Claim" shall mean a claim in an issued,  unexpired  patent
that  has  not  been  held  invalid  or   unenforceable  in  an  unappealed  and
unappealable judgment of a court of competent jurisdiction.

2.   Licenses

         2.1  License  to  Allergan.2  Subject to the other  provisions  of this
Agreement, SUGEN hereby grants to Allergan the following rights and licenses:

                  (a) an exclusive,  world-wide  royalty-free  license under the
Licensed  Technology to make and to use Drug  Candidates  and Back-Up  Compounds
therefor,  in order to conduct  pre-clinical  and clinical  development  of such
compounds  in  order  to  obtain  Regulatory  Approval  for use in the  Field as
Licensed Products;

                  (b) an exclusive,  world-wide,  royalty-bearing  license under
the Licensed  Technology,  to make,  have made,  use, sell,  offer for sale, and
import Licensed Products.

         2.2  Sublicensing.  Allergan  shall  have the right to  sublicense  the
rights granted by SUGEN in Section 2.1 to (i) Affiliates,  (ii) to third parties
in  countries in the Option  Market,  during the term of the Profit Share Option
granted in Section  5.1,  or after  SUGEN's  exercise of such  option,  with the
approval of SUGEN, which shall not be unreasonably  withheld, and (iii) to third
parties in countries in the Option  Market after the term of the option  granted
in Section 5.1, if SUGEN does not exercise  such Profit  Share  Option,  and all
countries outside the Option Market,  upon notice to SUGEN. Each such sublicense
shall  be  on  terms  substantially  consistent  with  those  provided  in  this
Agreement.

                                       5.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         2.3 Due Diligence.  Allergan shall devote the same degree of attention,
resources and diligence to its efforts to develop, manufacture,  market and sell
Licensed  Products as it devotes to its other  compounds of equivalent  economic
potential.  In the event  that  Allergan  does not file an IND  covering  a Drug
Candidate or a Back-Up Compound therefor [     ] after Allergan  designates such
Drug Candidate,  then such Active Compound and all Back-Up Compounds relating to
such compound shall no longer be Drug  Candidates,  and Allergan shall surrender
all  rights  to such  compounds  under  this  Agreement  and  the  Collaboration
Agreement.

         2.4 Obligation to Inform.  Allergan agrees to keep SUGEN fully informed
on a reasonable basis of the development and  commercialization  of all Licensed
Products, including but not limited to providing periodic written updates on the
progress of each filing for Regulatory Approval.

3.   PRODUCT DEVELOPMENT; MANUFACTURE AND SUPPLY

         3.1   Development of Drug Candidates By Allergan.

                  (a) Product  Development.  Allergan shall be  responsible  for
preparing and providing to SUGEN a Development  Plan for each Drug Candidate (or
Back-Up  Compound,  if in  development)  selected  by Allergan  for  development
pursuant to Section 4.5 of the Collaboration  Agreement and licensed  hereunder.
Allergan shall be responsible  for funding and performing the  Development  Plan
world-wide.  Allergan agrees to use commercially  reasonable  efforts to conduct
each such  Development Plan in order to obtain  Regulatory  Approval of Licensed
Products.

                  (b)  Disclosure  of Study Data.  Allergan  will provide  SUGEN
reports  at  least  [               ]  summarizing  all  preclinical,  clinical,
regulatory, commercial and other information, protocols, procedures, results and
communications  that result from the activities  under the  Development  Plan or
that  otherwise  relate  to  development  efforts  conducted  by or on behalf of
Allergan  or  its  Affiliates  with  respect  to  Drug  Candidates  and  Back-Up
Compounds.  In each such report,  Allergan  shall provide SUGEN a description of
the progress made during the [        ] towards obtaining Regulatory Approval of
Licensed  Products and the plans for the [       ].  In addition,  Allergan will
meet with SUGEN at least once every [        ] to discuss  results and  progress
of  Allergan's   development   efforts  hereunder,   and  will  give  reasonable
consideration  to any comments and suggestions from SUGEN regarding such results
or efforts.

   3.2  Manufacture  and Supply by Allergan.  Allergan will be  responsible  for
providing  at its own  expense  the  supply of all Drug  Candidate  and  Back-Up
Compounds  

                                       6.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

necessary  for   preclinical  and  clinical  development  of  Licensed  Products
and all Licensed Products necessary for commercialization worldwide.

4.   PAYMENTS

         4.1  Royalties.  Allergan  shall  pay  SUGEN a royalty  of  [     ]  on
world-wide Net Sales by Allergan,  its Affiliates or its  sublicensees.  For Net
Sales in a country in which: (i) no Valid Claim of a Licensed Patent exists, and
(ii) there is no claim in a pending patent application  included in the Licensed
Patents in such  country  covering the Licensed  Product  (with any  application
which has been  filed for more than  [     ]  without  issuance  being no longer
deemed "pending"),  and (iii) [

                                     ] then the payments due to SUGEN under this
Section 4.1 with  respect to the Net Sales in such country at such time shall be
[     ] In the event Valid Claims covering the Licensed  Product are established
or  reestablished  in such country,  or any [
                         ] the  payments  due to SUGEN with respect to Net Sales
after such date under this Section 4.1 shall revert to the full  percentage  set
forth above.

         4.2 Reimbursement of Royalties Due to Third Parties. In addition to the
royalty  obligation  under  Section  4.1,  Allergan  will  reimburse  SUGEN  all
royalties  paid by SUGEN to ArQule on Licensed  Products sold by Allergan in any
country, such reimbursement by Allergan not to exceed a total of [     ].  SUGEN
will provide to Allergan the information  reasonably necessary to determine such
third party royalties,  and such royalties shall be paid at the same time as and
in addition to the royalty payments made under Section 4.1.

         4.3 Credit of Milestone Payments.  Commencing with the [     ] calendar
quarter after the calendar quarter in which the first  royalty-bearing sale of a
Licensed  Product occurs in any country,  Allergan may credit against  royalties
otherwise  due SUGEN under  Section  4.1 of this  Agreement  an amount  equal to
[     ] of the total amounts of payments for milestones [     ] paid by Allergan
to SUGEN pursuant to Section 6.3 of the Collaboration Agreement (the "Creditable
Amount"); provided, however, that the amount so credited in any calendar quarter
shall not exceed [     ] of the royalties  otherwise payable for such quarter by
Allergan under Section 4.1 of this Agreement across all Licensed  Products,  and
further  provided  that the  aggregate  amount so credited  shall not exceed the
Creditable Amount.

         4.4 Period of Royalty Obligation.  The royalty obligation under Section
4.1 shall commence on the date of first commercial sale of a Licensed Product in
a country  and shall  expire,  on a  product-by-product  and  country-by-country
basis, upon the later of:


<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

(a) the  last  to  expire  patent  containing  a Valid  Claim  that  covers  the
manufacture,  use, sale,  offer for sale or import of such Licensed Product in a
country,  or  (b) the date  that is [     ] after the  date  of first commercial
sale of such Licensed Product in such country.


         4.5  Credit for  Certain  Patent  Costs.  Allergan  may credit  against
royalties  otherwise  due SUGEN under  Section 4.1 of this  Agreement  an amount
equal to [     ] of the total amounts expended by Allergan,  pursuant to Section
7.2  of  the  Collaboration   Agreement,   in  prosecuting  those  jointly-owned
Collaboration  Patents  relating  primarily to the [            ] (as defined in
the Collaboration Agreement) that claim the manufacture, use or sale of Licensed
Products  being sold by Allergan or its  Affiliates or  sublicensees;  provided,
however,  that the total of the amount so credited plus amounts  credited  under
Sections 4.3 and 7.4(c) in any calendar  quarter shall not exceed [     ] of the
royalties  otherwise  payable for such quarter by Allergan  under Section 4.1 of
this Agreement across all Licensed Products.

5.   PROFIT SHARING

         5.1 Profit Share Option.2  Allergan  hereby grants SUGEN an option (the
"Profit Share  Option"),  exercisable as provided below, to pay Allergan a share
of the Development  Costs of developing  Licensed Products in the Option Market,
in order to obtain  the right to a share in the  Profits  derived  from sales of
Licensed  Products in the Option  Market.  In order to evaluate the Profit Share
Option,  Allergan shall give SUGEN written  notice as soon as practicable  after
completion of Phase I that Allergan  intends in good faith to commence the first
Phase II (or equivalent)  clinical trial on a Drug Candidate or Back-Up Compound
in the Option  Market.  Such notice shall  include  details  about the plans and
reasonably expected  Development Costs for obtaining Regulatory Approval of such
Drug Candidate as a Licensed Product for sale in the Option Market. Allergan and
SUGEN shall exchange sales projections and any available marketing analyses then
in their  possession  for such  Licensed  Products  in the Option  Market.  Such
Development  Costs,  sales  projections  and market  analyses  shall be provided
without  warranty.  If SUGEN elects to exercise the Profit Share  Option,  SUGEN
shall provide  Allergan written notice of such exercise within [     ] after the
date of receipt of such notice from  Allergan,  and the parties shall proceed as
set forth below.

         5.2 Commitment to Pay Development  Costs. If SUGEN exercises the Profit
Share Option,  SUGEN agrees to pay Allergan for [     ] of the Development Costs
for the  Option  Market.  Within  [     ]  days  after  the end of a  particular
calendar  quarter,  Allergan  shall provide  SUGEN a report and invoice  setting
forth a summary of the Development Costs incurred in such quarter and the amount
equal to SUGEN's share hereunder of such costs, and an updated  Development Plan
and the budget for the 

                                       8.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

remaining  period of  development.  SUGEN shall make  payment to Allergan of its
share of such Development Costs within [     ] days of receipt of such invoice.

         5.3 Right to Share of Profits. If SUGEN has made payment of all amounts
of its share of the Development Costs,  Allergan shall pay SUGEN an amount equal
to [     ] of the Profits  resulting  from sales of Licensed  Product in [     ]
and [     ]of the Profits from sales of Licensed  Product in all other countries
of the Option Market.  Notwithstanding  the foregoing,  on a  country-by-country
basis  in  each  country  of the  Option  Market  where a  Valid  Claim  exists,
commencing  on the date (the  "Limitation  Date")  that is [     ]  prior to the
expiration of the last to expire of the patents for the Licensed Technology that
have issued in a particular  country in the Option Market  covering the Licensed
Product,  the  amount of the Profit  that SUGEN  shall be paid based on sales of
such Licensed  Products in such country  after the  applicable  Limitation  Date
shall not exceed,  as a percentage  basis of the Net Sales  attributable to such
sales of Licensed Products, the percentage that is represented by [

   ] divided by (b) [     ] during such quarter. For illustrative purposes, such
calculation of SUGEN's share of the Profits for sales of Licensed  Products made
after the Limitation Date in a particular country in the Option Market shall not
exceed, for a particular quarter:

[
                                                                               ]

         where "prior" quarter means the full calendar quarter just prior to the
Limitation Date.

         5.4  Payment of Share.  Within  [     ]  after the end of a  particular
calendar  quarter,  Allergan shall provide SUGEN a report and statement  setting
forth a summary of the total Net Sales of Licensed Products in the Option Market
during such quarter and a summary of the items  deducted from the Net Sales,  as
provided in Section 1.24, in  calculating  the Profit on such Licensed  Products
sales in the Option Market.  Such calculations  shall be broken into detail with
respect to [     ] as one  territory,  and the rest of the Option  Market as the
other territory, and the statement shall indicate the total amount owed SUGEN as
its share of such Profit,  based on the above share calculation.  Allergan shall
make payment to SUGEN of its share of such Profits at the same time as providing
such report,  but in no event later than [     ] after the end of the applicable
quarter.

         5.5 Right to Terminate Funding. At any time, SUGEN shall have the right
to terminate its funding obligation under Section 5.2 on [     ] written notice,
and in the event of such termination SUGEN shall not be entitled to any share of
Profits or to any refund of Development Costs paid by SUGEN.

                                       9.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

6.   PAYMENT: RECORD; AUDIT

6.1 Payments;  Reports.  All amounts payable to SUGEN under this Agreement shall
be paid in U.S. dollars.  The royalty  obligation under Section 4.1 shall accrue
at the  time  of  sale  of the  Licensed  Products  to a  third  party.  Royalty
obligations  that  accrue  during a  particular  quarter,  shall be paid  within
[     ] after the end of each calendar  quarter,  and other payments owing shall
be made as specified herein.  Each payment of royalties and amounts due to SUGEN
under  Sections 4.1 and 4.2 shall be accompanied by a statement of the amount of
Net Sales  during such  period on a  product-by-product  and  country-by-country
basis, and all other information  necessary to determine the appropriate  amount
of such payments,  and any additional  information or reports required under the
Agreement.

         6.2 Exchange  Rate.  The rate of exchange to be used in  computing  the
amount of currency  equivalent in United States  dollars due SUGEN shall be made
at the  period  end rate of  exchange  quoted  on the last  business  day of the
royalty period in the Wall Street Journal.

6.3 Records  and Audit.  During the term of this  Agreement  and for a period of
[     ] years  thereafter,  Allergan  shall keep  complete and accurate  records
pertaining  to  the  sale  or  other   disposition  of  the  Licensed   Products
commercialized  by it,  in  sufficient  detail to permit  SUGEN to  confirm  the
accuracy of all  payments due  hereunder  and  compliance  with the covenant set
forth in  Section  2.3.  SUGEN  shall  have the  right to cause an  independent,
certified  public  accountant  to audit such records to confirm  Allergan's  Net
Sales, royalty payments, and, if applicable,  calculation of Profits;  provided,
however,   that  such  auditor  shall  not  disclose   Allergan's   Confidential
Information  to SUGEN,  except to the extent such  disclosure  is  necessary  to
verify the amount of royalties and other payments due under this Agreement. Such
audits may be exercised  once a year,  within [     ] years after the royalty or
Profits period to which such records relate,  upon notice to Allergan and during
normal  business  hours.  Any amounts  shown to be owing by such audits shall be
paid  immediately  with  interest  in the  amount of  [     ]  per month (or the
maximum  amount  permitted by law, if less) from the date first owed until paid.
SUGEN  shall bear the full cost of such audit  unless  such  audit  discloses  a
variance in the amounts paid by Allergan of more than [     ] from the amount of
royalties and/or other payments actually owed. In such case, Allergan shall bear
the full  cost of such  audit.  The  terms of this  Section  shall  survive  any
termination or expiration of this Agreement for a period of [     ] years.

         6.4  Withholding  of  Taxes.  Any  withholding  of taxes  levied by tax
authorities  outside the United States on the payments  hereunder shall be borne
by  SUGEN  and  deducted  by  Allergan  from the sums  otherwise  payable  by it
hereunder for payment to the proper tax authorities on behalf of SUGEN. Allergan
agrees to  cooperate  with SUGEN in 

                                      10.

<PAGE>

the event SUGEN claims exemption from such withholding or seeks deductions under
any double  taxation or other similar  treaty or agreement  from time to time in
force,  such  cooperation  to consist of  providing  receipts of payment of such
withheld tax or other  documents  reasonably  available  to Allergan.  If in the
opinion  of  either  party  the  provisions  of this  Section  become  extremely
burdensome,  the parties  agree to meet and discuss such other options as may be
available to them.

         6.5  Blocked  Currency.  In each  country  where the local  currency is
blocked and cannot be removed  from the  country,  at the  election of Allergan,
royalties  accrued in that  country may be paid to SUGEN in the country in local
currency by deposit in a local bank designated by SUGEN.

         6.6 Non-Monetary Consideration. In the event Allergan or its Affiliates
or sublicensees  receives any non-monetary  consideration in connection with the
sale or other commercial transfer of Licensed Products,  Allergan's royalty and,
if  applicable,  reimbursement  obligations  to SUGEN under  Articles 3, 4 and 5
shall be based on the monetary value of such other consideration.  In such case,
Allergan shall  disclose the terms of such  arrangement to SUGEN and the parties
shall endeavor in good faith to agree on such monetary value.

7.   OWNERSHIP; PATENTS

         7.1 Ownership. Allergan acknowledges and agrees that SUGEN is and shall
remain  the sole  owner of the SUGEN  Technology  and  SUGEN's  interest  in the
Collaboration  Technology and that Allergan has no rights therein other than the
license  rights  specifically  granted  herein  or as  may  be  granted  by  the
Collaboration Agreement.

         7.2 Patents.  Provision is made in the Collaboration  Agreement for the
ownership,  filing,  prosecution and maintenance of Collaboration Patents, SUGEN
Patents and Allergan Patents and such matters shall be governed thereby.

         7.3   Infringement of Licensed Patents by Third Parties.67

                  (a)  Notice.  Each party  shall  promptly  notify the other in
writing of any alleged or threatened  infringement of the Licensed Patents which
may adversely  impact the rights of the parties  hereunder,  of which it becomes
aware.

                  (b)  Cooperation.  Both parties to this  Agreement  agree that
neither will notify a Third Party  (except for the parties'  outside  litigation
counsels) of the infringement of any of the Licensed Patents by a third party in
the Field without first obtaining the consent of the other party,  which consent
shall not be unreasonably  denied.  Both parties shall use their best efforts in
cooperating with each other to terminate such infringement  without  litigation,
with each party being responsible for the payment of its 

                                      11.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

own out-of-pocket  costs (including legal costs) relating thereto.  Any monetary
settlement  reached  shall,  after   reimbursement  of  both  parties  for  such
out-of-pocket  costs,  be divided  between the parties in accordance  with their
economic  interests  as directly  related to the  profitability  of the Licensed
Products.

                  (c)  Enforcement  Action.  In the event  that any  alleged  or
threatened  infringement  of the Licensed  Patents by a third party in the Field
cannot be terminated  without  litigation,  Allergan shall have the first right,
but not the obligation,  to take appropriate action against any person or entity
directly  or  contributorily  infringing  such  Licensed  Patent.  In the  event
Allergan fails to institute an infringement suit or take other reasonable action
in  response  to such  infringement  within  ninety  (90) days  after  notice in
accordance  with  paragraph (a) above,  SUGEN shall have the right,  but not the
obligation,  upon thirty (30) days' notice to Allergan to institute such suit or
take other appropriate  action in its own name, the joint owner's name, or both.
Regardless of which party brings such enforcement action, the other party hereby
agrees to  cooperate  reasonably  in any such  effort,  including,  if required,
bringing  a legal  action  or  furnishing  a power of  attorney.  The  party not
bringing  the action shall have the right to  participate  in such action at its
own expense  with its own counsel and any  recovery  obtained by  settlement  or
otherwise  shall be  disbursed  as follows:  Each party shall first  recover any
reasonable   expenses  incurred  in  such  action   (including   counsel  fees).
Thereafter,  the parties shall share any remaining  recovery in accordance  with
their  economic  interests  as  directly  related  to the  profitability  of the
product.

         7.4   INFRINGEMENT OF THIRD PARTY PATENT RIGHTS.

                  (a) Joint Strategy. In the event that the manufacture,  use or
sale of a Licensed  Product  becomes the subject of a claim of infringement of a
patent,  copyright or other proprietary right anywhere in the world, and without
regard to which party is charged with said  infringement,  and the venue of such
claim, the parties shall promptly confer to discuss the claim.

                  (b) Defense. Unless the parties otherwise agree, [     ] shall
have the first right but not the obligation to assume the primary responsibility
at its expense for the conduct of the defense of any such claim.  [     ]  shall
have the right,  but not the obligation,  to participate in any such suit at its
sole option and at its own expense.  Each party shall reasonably  cooperate with
the party  conducting  the defense of the claim.  Neither party shall enter into
any settlement  that affects the other party's rights or interests  without such
other party's written consent,  not to be unreasonably  withheld.  If [     ] in
its good faith,  reasonable  judgment  determines that payment must be made to a
third party (the "Third Party  Payment") in order to avoid  infringement of such
third party's patent, [     ] shall make such payment.

                                      12.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                  (c)  Allergan  Payment  Credit.  Allergan  may credit  against
royalties  otherwise  due SUGEN under  Section 4.1 of this  Agreement  an amount
equal to [     ] of the sum of the following  payments made or expenses incurred
by [     ] (i) Third Party Payments,  (ii) payments resulting from a final court
order or settlement  agreement entered into in good faith in connection with the
disposition of a third party claim of infringement, and (iii) costs and expenses
actually  incurred  in  defending  against  a third  party  infringement  claim;
provided, however, that the amount so credited in any calendar quarter, together
with any amount  creditable  for such  quarter  pursuant  to Section 4.3 of this
Agreement,  shall not exceed [     ] of the royalties otherwise payable for such
quarter by Allergan.  Any amounts which  Allergan is entitled to credit  against
royalties  under this  Section  7.4(c) shall be carried  forward  until all such
amount have been credited.

         7.5 Patent  Marking.  Allergan  shall mark, if necessary,  all products
manufactured,  used  or  sold  under  the  terms  of this  Agreement,  or  their
containers, in accordance with the applicable patent marking laws, as required.

8.   CONFIDENTIALITY

         8.1 Confidentiality.  Except to the extent expressly authorized by this
Agreement or otherwise agreed in writing by the parties, each party agrees that,
for the term of this Agreement and for five (5) years thereafter,  it shall keep
confidential  and shall not publish or otherwise  disclose and shall not use for
any  purpose  other than as  provided  for in this  Agreement  any  Confidential
Information furnished to it by the other party pursuant to this Agreement unless
the receiving party can  demonstrate by competent  proof that such  Confidential
Information:

                  (a) was already known to the receiving party, other than under
an obligation of confidentiality, at the time of disclosure by the other party;

                  (b) was generally available to the public or otherwise part of
the public domain at the time of its disclosure to the receiving party;

                  (c) became generally available to the public or otherwise part
of the public  domain  after its  disclosure  and other than  through any act or
omission of the receiving party in breach of such Agreements;

                  (d) was disclosed to the receiving party,  other than under an
obligation  of  confidentiality  to a third  party,  by a third party who had no
obligation to the disclosing  party not to disclose such  information to others;
or

                                      13.

<PAGE>

                  (e) was independently discovered or developed by the receiving
party without the use of  Confidential  Information  belonging to the disclosing
party.

         8.2  Authorized  Disclosure.   Each  party  may  disclose  Confidential
Information  belonging  to the other  party to the  extent  such  disclosure  is
reasonably necessary in the following instances:

                  (a)  filing  or  prosecuting   patents  relating  to  Licensed
Products;

                  (b) regulatory filings;

                  (c) prosecuting or defending litigation;

                  (d) complying with applicable governmental regulations;

                  (e)  conducting  pre  clinical or clinical  trials of Licensed
Products; and

                  (f)   disclosure  to  Affiliates,   sublicensees,   employees,
consultants or agents who agree to be bound by similar terms of  confidentiality
and non-use at least equivalent in scope to those set forth in this Article 8.

         Notwithstanding the foregoing, in the event a party is required to make
a disclosure  of the other  party's  Confidential  Information  pursuant to this
Section 8.2 it will, except where impracticable,  give reasonable advance notice
to the other  party of such  disclosure  and  endeavor  in good  faith to secure
confidential  treatment of such information.  In any event, the parties agree to
take all  reasonable  action to avoid  disclosure  of  Confidential  Information
hereunder. The parties will consult with one another and agree on the provisions
of this  Agreement  to be redacted in any filings  made by the parties  with the
United States  Securities  and Exchange  Commission or as otherwise  required by
law.

9.   REPRESENTATIONS AND WARRANTIES

         9.1 Representations and Warranties.  Each party represents and warrants
that:

                  (a) Corporate or Partnership  Power.  It is duly organized and
validly  existing  under the laws of its state or  country of  incorporation  or
organization,  and has full corporate or partnership  power, as applicable,  and
authority to enter into this Agreement and to carry out the provisions hereof.

                  (b) Due  Authorization.  It is duly  authorized to execute and
deliver this Agreement and to perform its obligations  hereunder.  The person or
persons executing this Agreement on its behalf has been duly authorized to do so
by all requisite corporate or partnership action, as applicable.

                                      14.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                  (c) Binding Agreement.  This Agreement is legally binding upon
it and  enforceable in accordance  with its terms.  The execution,  delivery and
performance of this  Agreement does not conflict with any agreement,  instrument
or understanding,  oral or written, to which it is a party or by which it may be
bound,  nor violate any material law or  regulation  of any court,  governmental
body or administrative or other agency having jurisdiction over it.

                  (d) Grant of Rights;  Maintenance of  Agreements.  It has not,
and will not during  this  Agreement,  grant any right to any third  party which
would conflict with the rights granted to the other party hereunder.  It has (or
will have at the time  performance is due) maintained and will maintain and keep
in full force and effect  all  agreements  (including  license  agreements)  and
filings   (including  patent  filings)  necessary  to  perform  its  obligations
hereunder.

                  (e)  Validity.  It is aware of no  action,  suit or inquiry or
investigation  instituted  by or before any court or  governmental  agency which
questions or threatens the validity of this Agreement or of any SUGEN Patent.

                  (f) Third Party  Rights.  Other than as disclosed to the other
Party, it is aware of no third party patent right that would be infringed by the
commercialization  of a Drug  Candidate  or  Back-Up  Compound  as  contemplated
hereby.

         9.2 Sugen Representations and Warranties. SUGEN represents and warrants
that it:

                  (a) owns or holds  licenses  to the  SUGEN  Patents  and SUGEN
Know-How and has  sufficient  rights and power to grant the licenses to Allergan
which it purports to grant herein.

                  (b)      [





                                                                               ]
and

                  (c)      [




         ]

[

                                                                               ]
                                      15.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         9.3 SUGEN  Disclaimer.  EXCEPT AS SET FORTH IN SECTIONS  9.1(f) AND 9.2
ABOVE, THE LICENSED TECHNOLOGY IS PROVIDED "AS IS" AND SUGEN EXPRESSLY DISCLAIMS
ANY AND ALL  WARRANTIES  OF ANY KIND,  EXPRESS  OR  IMPLIED,  INCLUDING  WITHOUT
LIMITATION THE WARRANTIES OF DESIGN,  MERCHANTABILITY,  FITNESS FOR A PARTICULAR
PURPOSE, NONINFRINGEMENT OF THE INTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES OR
ARISING FROM A COURSE OF DEALING,  USAGE OR TRADE  PRACTICES,  IN ALL CASES WITH
RESPECT  THERETO.  Without  limiting  the  generality  of the  foregoing,  SUGEN
expressly does not warrant (i) the success of any development or clinical trial,
study or test commenced by Allergan under this Agreement,  or (ii) the safety or
usefulness for any purpose of the Drug Candidates or the Licensed Technology.

         9.4 Allergan Disclaimer.  EXCEPT AS SET FORTH IN SECTIONS 9.1(f)AND 9.2
ABOVE,  ALLERGAN  EXPRESSLY  DISCLAIMS  ANY  AND  ALL  WARRANTIES  OF ANY  KIND,
EXPRESSED OR IMPLIED,  INCLUDING  WITHOUT  LIMITATION  THE WARRANTIES OF DESIGN,
MERCHANTABILITY,  FITNESS  FOR A  PARTICULAR  PURPOSE,  NONINFRINGEMENT  OF  THE
INTELLECTUAL  PROPERTY  RIGHTS  OF THIRD  PARTIES  OR  ARISING  FROM A COURSE OF
DEALING,  USAGE OR TRADE PRACTICES,  IN ALL CASES WITH RESPECT THERETO.  Without
limiting the  generality of the foregoing,  Allergan  expressly does not warrant
(i) the success of any development or clinical trial, study or test commenced by
Allergan  under  this   Agreement,   or  (ii)   regulatory   approval,   product
introduction, safety, usefulness or commercial success of any Licensed Product.

         9.5 SUGEN Grant of Rights.  SUGEN has not, and will not during the term
of this  Agreement,  grant any right to any third  party  which  would  directly
conflict with and materially impair the rights granted to Allergan hereunder.

         9.6 SUGEN Right to  Sublicense.  SUGEN  represents and warrants that it
has all right, power and authority necessary to sublicense Allergan under rights
licensed to SUGEN from third parties which are necessary for Allergan to exploit
the Licensed Technology as contemplated in Section 2.1.

10.   INDEMNIFICATION

         10.1 Indemnification. Each party hereby agrees to save, defend and hold
the other party and its agents and  employees  harmless from and against any and
all  suits,  

                                      16.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

claims,  actions,   demands,   liabilities,   expenses  and/or  loss,  including
reasonable legal expense and attorneys' fees, other than claims for infringement
as provided  in Section  7.4,  (collectively,  "Claims")  resulting  directly or
indirectly from actions by the  indemnifying  party,  its Affiliates,  agents or
sublicensees  in  connection  with  the  manufacture,  use or sale  of  Licensed
Products,  but only to the extent such Claims  result  from the  negligence  and
willful  misconduct  of the  indemnifying  party or its employees and agents and
only to the extent such Claims do not result  from the  negligence  of the party
seeking indemnification.

         10.2 Control of Defense.  Any entity entitled to indemnification  under
this Article shall give written notice to the  indemnifying  party of any Claims
that may be subject to  indemnification,  promptly after learning of such Claim,
and the indemnifying  party shall assume the defense of such Claims with counsel
reasonably  satisfactory to the indemnified party. If such defense is assumed by
the indemnifying party with counsel so selected, the indemnifying party will not
be  subject to any  liability  for any  settlement  of such  Claims  made by the
indemnified party without its consent (but such consent will not be unreasonably
withheld or delayed),  and will not be obligated to pay the fees and expenses of
any  separate  counsel  retained by the  indemnified  party with respect to such
Claims.

11.   TERM AND TERMINATION OF AGREEMENT

         11.1 Term. Except as provided under Section 11.2 below, (a) the term of
this  Agreement  shall  commence upon the Effective Date and shall expire on the
expiration date of the last to expire royalty  obligation or obligation to pay a
share of Profit, and (b) upon expiration of this Agreement,  Allergan shall have
a fully paid, exclusive license to use any Licensed Know How to make, have made,
use and sell  Licensed  Products  for use within the  Field,  and a fully  paid,
nonexclusive  license  under SUGEN's  interest in the Licensed  Know-How for any
other use within the Field.

         11.2 Termination for Material  Breach.  Each party shall have the right
to terminate the Agreement  after [       ] written notice to the other that the
other is in material  breach of the Agreement,  unless the other party cures the
breach before the  expiration of such period of time,  or, in the case that such
breach cannot be cured within such period,  the party  continues to use diligent
efforts to cure such breach until actually  cured.  In addition,  this Agreement
shall terminate in the event the Collaboration  Agreement is terminated pursuant
to  Section  5.3  thereof.  Upon  termination,   all  licenses  granted  to  the
non-breaching  party shall  survive and all  licenses  granted to the  breaching
party under the Agreement shall  automatically  terminate,  but such termination
shall not impair any other  rights  the  non-breaching  party may have at law or
equity.

                                      17.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         11.3  Termination at Election of Allergan.  Allergan may terminate this
Agreement in its entirety at any time upon not less than [      ] days notice to
SUGEN,  without  liability  to  SUGEN;   provided,   however,  that  after  such
termination  Allergan shall not directly or indirectly  make, have made, use, or
sell any Licensed  Products.  Allergan may terminate this Agreement with respect
to any Drug  Candidate  and/or  Back-Up  Compound at any time upon not less than
[      ]  notice  to SUGEN,  provided,  however,  that  after  such  termination
Allergan  shall not  directly or  indirectly  make,  have made,  use or sell any
products incorporating such Drug Candidate or Back-Up Compound.

         11.4  Termination of  Collaboration  Agreement.  This  Agreement  shall
automatically  terminate if the Collaboration  Agreement  terminates pursuant to
the following sections of the Collaboration  Agreement:  Sections 5.3, 6.4, 10.2
due to Allergan's uncured material breach, 10.3 or 10.4.

         11.5  Accrued  Rights;  Surviving  Obligations.   Termination  of  this
Agreement  shall not affect any  accrued  rights of either  party.  The terms of
Articles 7, 8, 10, 11 and 12 of this Agreement shall survive termination of this
Agreement.  Promptly after termination of this Agreement each party shall return
or dispose of any Confidential Information and other know how of the other party
in accordance with its instructions, including without limitation any compounds,
assays or other biological or chemical materials.

12.   GOVERNING LAW; DISPUTE RESOLUTION

         12.1 Governing Law. This Agreement shall be governed by California law,
excluding its choice of law rules.

         12.2 Dispute Resolution. In the event of any dispute, the parties shall
refer such dispute to the Chief Executive  Officer or President of each of SUGEN
and Allergan for attempted  resolution by good faith negotiations  within thirty
(30) days after such referral is made during which time, any applicable statutes
of limitations  and/or time periods hereunder shall be tolled. In the event such
officers are unable to resolve such dispute  within such thirty (30) day period,
either party may invoke the provisions of Section 12.3 below.

         12.3 Jurisdiction and Venue.  Except as provided in Section 12.2 above,
any claim or  controversy  arising  out of or related to this  Agreement  or any
breach  hereof  shall be  submitted  to a state  or  federal  court  of  general
jurisdiction  in the State of California,  and the parties hereby consent to the
jurisdiction and venue of such court.

                                      18.

<PAGE>

13.   GENERAL PROVISIONS

         13.1 Notices.  All notices required or permitted to be given under this
Agreement  shall be in writing and shall be mailed by  registered  or  certified
mail,  Federal  Express or DHL addressed to the signatory to whom such notice is
required or  permitted  to be given and  transmitted  by facsimile to the number
indicated below. All notices shall be deemed to have been given when mailed,  as
evidenced by the postmark at the point of mailing, or faxed.

         All notices to Allergan shall be addressed as follows:

                  Vision Pharmaceuticals, L.P.
                  c/o Allergan, Inc.
                  Attention:  Vice President, Corporate Development
                  2525 Dupont Drive
                  Irvine, CA 92713
                  Fax:  (714) 246-4774

                  with a copy to:

                  Allergan, Inc.
                  Attention:  General Counsel
                  2525 Dupont Drive
                  Irvine, CA 92713
                  Fax:  (714) 246-4774

         All notices to SUGEN shall be addressed as follows:

                  SUGEN, INC.
                  515 Galveston Drive
                  Redwood City, CA 94063 4720
                  Attn: President
                  Fax: (415) 369-0741

                                      19.

<PAGE>

                  with a copy to:

                  Cooley Godward L.L.P.
                  Five Palo Alto Square
                  3000 El Camino Real
                  Palo Alto, California  94306
                  Attn:  Brian C. Cunningham, Esq.
                  Fax:  (415) 857-0663

         Any party may, by written notice to the other,  designate a new address
or fax number to which  notices to the party giving the notice shall  thereafter
be mailed or faxed.

         13.2  Compliance  with Laws.  Allergan  and SUGEN shall  review in good
faith and cooperate in taking actions to ensure the compliance of this Agreement
with all applicable laws.  Allergan and SUGEN shall each provide the other party
with such reasonable assistance as may be required for the party requesting such
assistance to comply with all laws, ordinances,  rules, regulations and the like
of all  governmental  units or agencies having  jurisdiction  pertaining to this
Agreement, including without limitation,  obtaining all import, export and other
permits,  certificates,  licenses or the like required by such laws, ordinances,
rules,  regulations  and the like,  necessary  to permit the  parties to perform
hereunder and to exercise their respective rights hereunder.

         13.3 Force  Majeure.  No party shall be liable for any delay or failure
of  performance  to the extent such delay or failure is caused by  circumstances
beyond its  reasonable  control and that by the exercise of due  diligence it is
unable to prevent, provided that the party claiming excuse uses its best efforts
to overcome the same.

         13.4 Entirety of Agreement.  This Agreement embodies the entire,  final
and complete  agreement and  understanding  between the parties and replaces and
supersedes all prior discussions and agreements between them with respect to its
subject  matter.  No  modification  or waiver of any terms or conditions  hereof
shall be  effective  unless  made in  writing  and  signed by a duly  authorized
officer of each party.

         13.5 Non Waiver. The failure of a party in any one or more instances to
insist  upon  strict  performance  of any of the  terms and  conditions  of this
Agreement shall not constitute a waiver or relinquishment, to any extent, of the
right to  assert  or rely  upon  any such  terms  or  conditions  on any  future
occasion.

         13.6 Disclaimer of Agency.  Neither party is, nor will be deemed to be,
the legal  representative or agent of the other, nor shall either party have the
right or  authority  to assume,  create,  or incur any third party  liability or
obligation  of any kind,  express  or  

                                      20.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

implied,  against or in the name of or on behalf of another  except as expressly
set forth in this Agreement.

         13.7 Severability.  If a court of competent  jurisdiction  declares any
provision of this Agreement  invalid or  unenforceable,  or if any government or
other  agency  having  jurisdiction  over  either  SUGEN or  Allergan  deems any
provision to be contrary to any laws,  then that provision  shall be severed and
the remainder of the Agreement  shall continue in full force and effect.  To the
extent possible, the parties shall revise such invalidated provision in a manner
that will render such provision  valid without  impairing the parties'  original
intent.

         13.8  Affiliates;  Assignment.  Except as  otherwise  provided  herein,
neither party may assign its rights or delegate its duties under this  Agreement
without the prior  written  consent of the other party,  not to be  unreasonably
withheld;  provided, however, that either party may assign this Agreement to any
of its Affiliates or to any successor by merger or sale of substantially  all of
its  business  unit to which this  Agreement  relates in a manner  such that the
assignor will remain liable and  responsible  for the performance and observance
of all its duties and  obligations  hereunder.  This Agreement  shall be binding
upon  the  successors  and  permitted  assigns  of the  parties.  Any  attempted
delegation or assignment not in accordance with this Section 13.8 shall be of no
force or effect.  Notwithstanding the foregoing provisions of this Section 13.8,
[
                                                                               ]

         13.9 Headings. The headings contained in this Agreement have been added
for convenience only and shall not be construed as limiting.

         13.10 Limitation of Liability.  No party shall be liable to another for
indirect,  incidental,  consequential  or  special  damages,  including  but not
limited  to  lost  profits,  arising  from or  relating  to any  breach  of this
Agreement,  regardless of any notice of the possibility of such damages. Nothing
in this Section is intended to limit or restrict the  indemnification  rights or
obligations of any party.

         13.11  Counterparts.  This  Agreement  may be  executed  in one or more
counterparts,  each  of  which  shall  be an  original  and all of  which  shall
constitute together the same document.

         13.12 English Language. This Agreement has been prepared in the English
language and shall be construed in the English language.

         13.13  Public  Announcement.  Except for such  disclosure  as is deemed
necessary, in the reasonable judgment of a party, to comply with applicable laws
or regulations, no announcement, news release, public statement,  publication or
presentation  relating to the existence of this Agreement,  or the terms hereof,
will be made without the other party's 

                                      21.

<PAGE>

prior written approval,  which approval shall not be unreasonably  withheld. The
parties agree that they will use  reasonable  efforts to coordinate  the initial
announcement  or press release  relating to the  existence of this  Agreement so
that   such   initial   announcement   or   press   release   by  each  is  made
contemporaneously.

         13.14  Guarantee.  Allergan,  Inc.  guarantees the  performance of each
obligation of Vision Pharmaceuticals,  L.P. under this Agreement, whether or not
Allergan,  Inc.  has  received  any  notice  which is to be  provided  to Vision
Pharmaceuticals, Inc. pursuant to this Agreement.



         IN  WITNESS  WHEREOF,  the  parties  hereto  have  duly  executed  this
Agreement.



SUGEN INC.                              VISION PHARMACEUTICALS, L.P., a
                                        Texas limited partnership, dba Allergan,
                                        by Allergan General, Inc., its general
                                        partner


By:                                     By:
     -------------------------------           ---------------------------------
Name:                                   Name:  Francis R. Tunney, Jr.
     -------------------------------           ---------------------------------
Title:                                  Title: Secretary
     -------------------------------           ---------------------------------


Guarantee of performance given by:


ALLERGAN, INC.



By:
     -------------------------------
Name:
     -------------------------------
Title:
     -------------------------------


                                      22.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                                    EXHIBIT A

                                LICENSED PATENTS

                            [                                                 ]


                                      23.

<PAGE>

                                    EXHIBIT B

                      DRUG CANDIDATES AND BACKUP COMPOUNDS




                                      24.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                                    EXHIBIT C

                                DEVELOPMENT COSTS

[














                                                                               ]

                                      25.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[















                                                     ]


                                      26.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

                   [












                          ]

                                      27.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


                                    EXHIBIT D

                             OPTION MARKET COUNTRIES


                                                         [






                           ]

                                      28.

<PAGE>



3                                               CONFIDENTIAL TREATMENT REQUESTED


                                    EXHIBIT C

                             EXISTING SUGEN PATENTS

                                     [     ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED



[





                                            ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


[













                                                                       ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


[







                                                                       ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


                                    EXHIBIT D

                               EXCLUDED COMPOUNDS



The SUGEN compounds identified internally as:

         [

                    ]



<PAGE>


                                    EXHIBIT E

                                  RESEARCH PLAN





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[






                                                              ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED


[









           ]






<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[











                                                              ]






<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[













                                                              ]




<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[













                           ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED
                                                         [









                                                                               ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[








                                                                            ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[












                                                                              ]





<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[











                                                                               ]




<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[















                                                                               ]




<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

[











                                                                               ]




<PAGE>



                                    EXHIBIT F

                                  PRESS RELEASE





   
   

<PAGE>




For Immediate Release               SUGEN Contact:      Nina W. Ferrari
                                                        (415) 306-7700 (office)
                                                        [email protected]

                                                        Burns McClellan, Inc.
                                                        Justin Jackson
                                                        (212) 505-1919

                                    Allergan Contact:   Jeff  D'Eliscu
                                                        (714)  246-4636 (office)
                                                        (714)  675-9475 (home)


               SUGEN AND ALLERGAN COLLABORATE TO FIGHT OPHTHALMIC
                      DISEASES WITH ANGIOGENESIS INHIBITORS

Redwood City, CA, Irvine, CA, October 8, 1996 -- SUGEN, Inc. (Nasdaq:  SUGN) and
Allergan,  Inc.  (NYSE:  AGN)  announced  today that they have  entered  into an
exclusive   collaboration   to  identify,   develop  and   commercialize   novel
pharmaceutical  compounds  utilizing  SUGEN's  proprietary small molecule signal
transduction inhibition technology for the treatment of ophthalmic diseases.

During  the course of the  collaboration,  Allergan  will be  SUGEN's  exclusive
corporate partner in the ophthalmic field and will have rights to all ophthalmic
uses  of  collaboration  products  and  technology  worldwide.   SUGEN  will  be
responsible  for identifying and validating  novel signal  transduction  targets
which  contribute to ophthalmic  diseases.  SUGEN will also be  responsible  for
assay design and identification of target specific lead compounds. Allergan will
take  responsibility  for in vivo ophthalmic disease models and for preclinical,
clinical and commercial  development of all collaboration  drug candidates.  The
collaboration will focus initially on the development of angiogenesis inhibitors
for the treatment of ophthalmic neovascular diseases such as age-related macular
degeneration and diabetic retinopathy.

Allergan will pay SUGEN a $2 million initial  research payment and is purchasing
$4 million of SUGEN  Common  Stock at $20.88 per share.  Additionally,  Allergan
intends to  purchase  $3 million of SUGEN  Common  Stock at the market  price of
SUGEN's next equity  offering.  SUGEN will receive  research and drug  discovery
funding  for  three  years,  as well as  milestone  payments  and  royalties  on
worldwide sales of any collaboration products. In addition,  SUGEN will have the
right to contribute to Phase II/III clinical  development costs on each program,
thereby  earning  participation  in the profits  from  successful  collaboration
products in North America and Europe over and above its royalty entitlements.
                                     -more-



<PAGE>

"Recent advances in our understanding of the signalling  mechanisms  involved in
new blood vessel growth suggest that  intervening  against certain growth factor
receptors  and their  associated  signalling  pathways  may  provide a promising
approach to the  development of novel  angiogenesis  inhibitors,"  commented Dr.
Lester J. Kaplan, corporate vice president,  Science and Technology of Allergan.
"We believe that combining the  technologies  developed by SUGEN with Allergan's
ophthalmic  research  provide the  opportunity  for defining the correct  signal
trasduction  targets and for developing novel  target-specific  drugs to address
major ophthalmic diseases."

"SUGEN  is  very  pleased  to  be   partnering   with  an  industry   leader  in
ophthalmology.  Ophthalmic  diseases  represent a major area of opportunity  for
SUGEN's drug discovery platform,  but clearly it did not make sense for SUGEN to
bring in-house the preclinical, clinical and marketing expertise that are unique
to drug  development  in  ophthalmology.  This  collaboration  will optimize the
complementary  strengths of both companies in this field." stated Stephen Evans-
Freke, Chairman and CEO of SUGEN, Inc.

The retinal  neovascularization  associated  with ophthalmic  diseases,  such as
age-related macular degeneration and diabetic retinopathy,  is a key contributor
to vision loss. This  neovascularization  can be provoked when too little oxygen
is available to the eye. The retina then becomes  hypoxic  (oxygen  starved) and
responds by secreting messenger proteins that trigger the sprouting of new blood
vessels which can compromise  vision quality and in severe cases lead to loss of
sight.  Macular  degeneration in particular  constitutes a patient population of
over five million in North America,  for whom there is no  satisfactory  therapy
currently available.

Allergan,  Inc.,  headquartered in Irvine,  California,  is a technology-driven,
global  health care  company  focused on specialty  pharmaceutical  products for
specific  disease areas that deliver  value to customers,  satisfy unmet medical
needs and improve patients' lives.

SUGEN,  Inc. is a  biopharmaceutical  company focusing on the development of new
classes  of small  molecule  drugs  which  interact  in a specific  manner  with
different   members  of  the   tyrosine   kinase,   tyrosine   phosphatase   and
serine-threonine  kinase families of signal  transduction  molecules,  and their
signalling  pathways.  These pathways are involved in a number of human diseases
including  cancer  and  diabetes,  as well as  disorders  of the  body's  immune
defenses and  neurological  systems.  The Company has  research and  development
collaborations  with  Zeneca  and  ASTA  Medica,  as well  as two  Collaborative
Research and Development Agreements (CRADAs) with the National Cancer Institute.

                                       ###






                                                                   EXHIBIT 10.59

           Certain   confidential   information   contained  in  this
           document, marked by brackets, is filed with the Securities
           and  Exchange  Commission  pursuant  to Rule  24b-2 of the
           Securities Exchange Act of 1934, as amended.




                                    AMENDMENT

         THIS  AMENDMENT  AGREEMENT is made effective as of May 31, 1996, by and
between Sugen,  Inc.  ("Sugen") and Yissum Research  Development  Company of the
Hebrew University of Jerusalem ("Yissum").

         WHEREAS,  Sugen and Yissum  are  parties  to an  Amended  and  Restated
Research and License  Agreement  effective  March 27,  1995,  as to research and
development regarding the prevention,  mitigation,  treatment, cure or diagnosis
of cancer and  angiogenesis  diseases and disorders (the "Research  Agreement");
and

         WHEREAS, Sugen and Yissum desire to amend the Research Agreement as set
forth  below  pursuant  to the  provisions  of  Section  18(e)  of the  Research
Agreement;

         NOW,  THEREFORE,  in  consideration  of the  premises  and  the  mutual
covenants  herein  contained,  and for  good  and  valuable  consideration,  the
sufficiency  of which is hereby  acknowledged,  Sugen and Yissum hereby agree as
follows:

         1.  Capitalized  terms used herein  without  definition  shall have the
meanings ascribed to them in the Research Agreement.

         2. The  definition  of  "Research  Period" in Section 1 of the Research
Agreement  is  hereby  amended  by  deleting  the term  "June  1,  1996" in such
definition and replacing such term with the term "June 1, 1997"

         3. Section 1 of the Research  Agreement is hereby amended by adding the
following new definition to the text thereof:

            "Work Plan"  -  means  each  of the periodic work plans described in
            Section 2(b)."

         4. Section 2(b) of the Research  Agreement is hereby  amended by adding
the following new text to the end thereof:

         "Yissum hereby agrees to procure the production of Work Plans,  and the
         Research's performance in accordance with each Work Plan, in accordance
         with this  Agreement.  Yissum shall cause the  Researcher  to produce a
         Work Plan, in form and substance reasonably  satisfactory to Sugen, for
         each twelve-month period (or lesser period or periods if agreed between
         the parties)  during the Research  Period prior to the  performance  of
         services  thereunder  and in no event  later than the date of October 1
         (or,  if  earlier,  the date that is the last day of any agreed to Work
         Plan) during each year during the Research Period.  Each Work Plan will
         set forth goals,  objectives and a time line and will include,  without
         limitation,  priorities and guidelines in connection  with the Research
         to be performed."



                                       1.

<PAGE>

                                                CONFIDENTIAL TREATMENT REQUESTED

         5. Section 3(a) of the Research Agreement is hereby amended by deleting
the text thereof and substituting the following:

         "In  consideration  for the performance of the Research and in order to
         finance it, Sugen  undertakes  to pay Yissum at the rate of [     ] per
         year beginning on October 1, 1994 and ending on May 31, 1996 and at the
         rate of [     ] per year  beginning  on June 1, 1996 and ending on June
         1, 1997. Payments shall be made in advance in quarterly installments."

         6. The parties hereto  acknowledge  that as of September 1, 1996, Sugen
has paid to Yissum, and Yissum has received, [       ] of the [    ] referred to
in Section 3(a) of the Research Agreement as amended as set forth above.

         7. The term "Agreement" as used in the Research Agreement and all other
instruments and agreements  executed  thereunder shall for all purposes refer to
the Research Agreement as amended by this Amendment Agreement.

         8.  Except  to the  extent  expressly  amended  by the  terms  of  this
Amendment Agreement,  all the terms and conditions of the Research Agreement and
all other  instruments and agreements  executed  thereunder remain in full force
and effect.

         9. Sugen hereby  represents  and warrants to Yissum that the  execution
and  delivery  of this  Amendment  Agreement  have been duly  authorized  by all
requisite action on the part of Sugen.  Yissum hereby represents and warrants to
Sugen that the execution and delivery of this Amendment Agreement have been duly
authorized by all requisite action on the part of Yissum.

         10. This Amendment Agreement may be executed in any number of duplicate
counterparts,  each of  which  shall  be  deemed  an  original  and all of which
together shall constitute one and the same instrument.

         IN  WITNESS  WHEREOF,  the  parties  have duly  signed  this  Amendment
Agreement effective as of the day and year first written above.


SUGEN, INC.                                      YISSUM RESEARCH DEVELOPMENT
                                                 COMPANY OF THE HEBREW
                                                 UNIVERSITY OF JERUSALEM



By: /s/ K. Peter Hirth                         By: /s/ Uri Litvin
    ---------------------------------------       ------------------------------
        Name:  K. Peter Hirth, Ph.D.                   Name:  Uri Litvin
        Title:   Executive Vice President              Title:  Managing Director
                 Drug Research & Development


                                       2.




                                                                   EXHIBIT 10.60














[SUGEN LETTERHEAD]


July 18, 1996


James L. Tyree
950 Vista Drive
Hillsborough CA 94010

Dear Jim:

         This letter sets forth the separation agreement (the "Agreement") which
SUGEN, Inc. (the "Company") is offering to you.

         1. SEPARATION.  Your last day of work with the Company shall be June 6,
1996 (the  "Separation  Date").  You agree that,  effective as of the Separation
Date,  you hereby  resign as an  employee  of the  Company and as an officer and
director of the Company. You agree to provide the Company with a separate letter
of  resignation  to that effect,  no later than the Effective  Date. The Company
agrees to retain you, and you agree to serve as a consultant to the Company, and
to make yourself  available for such  purposes  upon  reasonable  request by the
Company, until October 9, 1997. The Company agrees that such services are deemed
to be "employment"  for the purposes of your stock option  agreements but for no
other purposes.

         2. ACCRUED SALARY;  PAID TIME OFF. You acknowledge that on or about the
Separation  Date, the Company paid you all accrued  salary,  and all accrued and
unused vacation earned through the Separation Date,  subject to standard payroll
deductions and withholdings.

         3. STOCK OPTIONS. The Company shall continue to vest your stock options
as shown on the attached  Exhibit A for twelve (12) months after the  Separation
Date.  This will result in your  vesting in up to 38,667  additional  options to
purchase Company stock. In accordance with your option agreements,  the exercise
period for all of your vested options will continue until January 9, 1998.

         4. SEVERANCE  PACKAGE.  The Company will make severance payments to you
in the form of continuance of your base salary in effect on the Separation  Date
for twelve (12) months following the Separation Date. You acknowledge that these
payments have already begun. They will be made on the Company's ordinary payroll
dates,  and will be subject to standard payroll  deductions and withholding.  In
addition,  the Company has since the Separation  Date, and will continue to loan
you a monthly  maximum of three thousand  dollars  ($3,000)  toward your monthly
mortgage  payment,  until the earlier of the sale of the property or twelve (12)
months  after the  Separation  Date,  but in no event  fewer than six (6) months
after the Separation Date. The Company agrees not to declare an Event of Default
as defined in that  certain Loan  Agreement  dated August 29, 1994 (set forth in
Exhibit B), under paragraph 9(b) of the Loan  Agreement,  until January 1, 1998.
The Company will also pay you, upon your  repayment of your loan  obligations to
the  Company  as  provided  for in  paragraph  5 below,  an amount  equal to the
Financing Loans advanced to you pursuant to the Loan Agreement. This amount will
be no less than $76,103.60 and no greater than


<PAGE>



James L. Tyree
July 18, 1996
Pag 2



$94,103.60,  and will be subject to standard payroll deductions and withholding,
including  deductions  and  withholding  based on your  income  by reason of the
forgiveness of your loan  obligations and  forgiveness of your interest  payment
obligation.  In addition, the Company will reimburse you for the reasonable cost
of office  service  (not to exceed $800 per month) for six (6) months  after the
Effective Date, or until such time as you commence other employment.

         5.  RESIDENTIAL  LOAN.  The Company  will forgive in part and modify in
part those certain  Promissory  Notes Secured by Deed of Trust in the amounts of
$175,000  and "Up To  $130,500.00,"  respectively,  dated  August 29,  1994 (the
"Notes"),  which Notes are secured by a Short Form Deed of Trust and  Assignment
of Rents of even date (the "Lien"),  copies of which are attached hereto as part
of Exhibit B, as follows:

                  a.       Of the unpaid  balance of  $175,000.00,  the  Company
                           will forgive your  obligation to pay $87,500.00  upon
                           your   repayment   of  the   remaining   balance   of
                           $87,500.00;

                  b.       The remaining  balance of $87,500.00  will become due
                           and payable by you upon the earlier of:

                           i.       The   sale,   transfer,    conveyance,    or
                                    assignment  of  any  interest  in  the  real
                                    property  which is currently  the subject of
                                    the Lien;

                           ii.      January 1, 1998;

                           iii.     Any other Event of Default as defined in the
                                    Loan Agreement.

                  c.       The Company  will  forgive the  Financing  Loans,  as
                           defined  in the Loan  Agreement,  and  your  interest
                           obligations on all of your loans, upon your repayment
                           of the  remaining  balance of $87,500.00 of your loan
                           obligation.  You  acknowledge and understand that the
                           taxing authorities require the imputation of interest
                           in this circumstance,  and that such imputed interest
                           will be reflected in your tax statement.

                  d.       The Company will execute a release of the Lien ("Lien
                           Release")  in a form set  forth in  Exhibit  C, to be
                           held in escrow by Company counsel until the Effective
                           Date of this Agreement. The Lien Release shall not be
                           effective until this Agreement  takes effect,  on the
                           Effective  Date,  within two  business  days of which
                           date  the  Company's  counsel  shall  file  the  Lien
                           Release with the County of San Mateo.

         6.  TERMINATION OF AGREEMENTS.  Subject to the provisions of paragraphs
13 and 15 below,  and except for the provisions of the  Proprietary  Information
and Inventions  Agreement as referenced in paragraph 11 of this  Agreement,  you
and the Company agree to terminate as of June 6,


<PAGE>



James L. Tyree
July 18, 1996
Page 3



1996 that certain offer letter agreement  ("Offer Letter") dated April 28, 1994,
signed  by  you  on  May  2,  1994,  and  to  terminate  that  certain  Deferred
Compensation Agreement dated August 29, 1994.

         7. HEALTH  INSURANCE.  To the extent permitted by the federal COBRA law
and by the  Company's  current  group  health  insurance  policies,  you will be
eligible to continue your health insurance  benefits,  and the Company agrees to
pay your health  insurance  continuation  premiums  for twelve (12)  consecutive
months through June 30, 1997; provided,  however,  that the Company's obligation
to make such payments shall cease  immediately if you become  eligible for other
health  insurance  benefits  at the  expense of another  employer.  You agree to
notify a duly authorized  officer of the Company,  in writing,  immediately upon
your acceptance of any employment which provides health insurance benefits.

         8. OTHER  COMPENSATION  OR BENEFITS.  You acknowledge  that,  except as
expressly  provided  in this  Agreement,  you will not  receive  any  additional
compensation,  severance or benefits after the  Separation  Date. In particular,
this includes without  limitation,  cancellation of paid life insurance benefits
and  vacation  accrual.   However,   if  permitted  by  the  Plan's  eligibility
requirements, you may continue to participate in the Company's 401(k) Plan.

         9. EXPENSE REIMBURSEMENTS. You acknowledge that you have submitted your
final  documented  expense  reimbursement   statement  reflecting  all  business
expenses you incurred  through the  Separation  Date, if any, for which you seek
reimbursement  and  that the  Company  has  reimbursed  you for  these  expenses
pursuant to its regular business practice.

         10. RETURN OF COMPANY PROPERTY. You represent that you have returned to
the Company all Company  documents  (and all copies  thereof) and other  Company
property which you have had in your possession at any time,  including,  but not
limited  to,  Company  files,  notes,  drawings,  records,  business  plans  and
forecasts,   financial   information,    specifications,    computer-   recorded
information,  tangible  property  (including,  but not limited  to,  computers),
credit cards, entry cards, identification badges and keys; and, any materials of
any kind which contain or embody any proprietary or confidential  information of
the Company (and all reproductions thereof).

         11.  PROPRIETARY  INFORMATION  OBLIGATIONS.  Both during and after your
employment you acknowledge  your continuing  obligations  under your Proprietary
Information and Inventions  Agreement not to use or disclose any confidential or
proprietary  information of the Company without prior written authorization from
a duly  authorized  representative  of the Company.  A copy of your  Proprietary
Information and Inventions Agreement is attached hereto as Exhibit D.

         12. CONFIDENTIALITY.  The provisions of this Agreement shall be held in
strictest  confidence  by you and the  Company  and shall not be  publicized  or
disclosed  in any  manner  whatsoever;  provided,  however,  that:  (a)  you may
disclose this Agreement to your immediate  family;  (b) the parties may disclose
this  Agreement  in  confidence  to  their  respective  attorneys,  accountants,
auditors,  tax preparers,  and financial advisors;  (c) the Company may disclose
this Agreement as necessary to fulfill  standard or legally  required  corporate
reporting or disclosure


<PAGE>



James L. Tyree
July 18, 1996
Page 4



requirements;  (d) the  parties  may  disclose  this  Agreement  insofar as such
disclosure  may be necessary  to enforce its terms or as  otherwise  required by
law;  and  (e)  the  Company   agrees  to  notify  its  key   employees  of  the
nondisparagement agreement in paragraph 13 below.

         13.  NONDISPARAGEMENT.  Both you and the Company agree not to disparage
the  other  party,  and  the  other  party's  officers,  directors,   employees,
shareholders  and  agents,  in any manner  likely to be harmful to them or their
business, business reputation or personal reputation; provided that both you and
the Company  shall  respond  accurately  and fully to any  question,  inquiry or
request for  information  when  required by legal  process.  In the event of any
breach of this paragraph by you, the Company will have the right to stop further
performance of this Agreement  immediately,  including without  limitation,  the
termination of your consulting  arrangement,  salary  continuance,  stock option
vesting,  forgiveness  of loan  obligations  and interest,  payment of Financing
Loans,  payment of the amount equal to the Financing Loans, and health coverage.
In the event of any breach of this  paragraph by the Company,  you will have the
right to declare this Agreement to be null and void in all respects.

         14. RELEASE. In exchange for the payments and other consideration under
this  Agreement  to which you  would not  otherwise  be  entitled,  you agree to
execute the Employee Agreement and Release attached hereto as Exhibit E.

         15.  DEFAULT.  Without  limiting  either party's rights in paragraph 13
above,  your material  default of any of the  provisions of this  Agreement will
give the Company the  immediate  right to terminate its further  performance  of
this Agreement,  and a material  default by the Company will permit you, at your
option to (a) seek  enforcement of the terms of this  Agreement;  or (b) declare
this  Agreement  to be null and void in all  respects,  including  the  Employee
Agreement and Release.

         16. CONFIDENTIAL ARBITRATION. To ensure rapid and economical resolution
of any and all disputes which may arise in connection with this  Agreement,  you
and the Company agree that any and all disputes,  claims,  causes of action,  in
law or equity,  arising from or relating to this  Agreement or its  enforcement,
performance,  breach,  or  interpretation,  with  the  sole  exception  of those
disputes which may arise from either (a) your Proprietary Information Agreement,
or (b) the  provisions  of  paragraph  13 above,  shall be resolved by final and
binding  confidential  arbitration  held in San  Francisco,  California  through
Judicial  Arbitration & Mediation  Services/Endispute,  Inc.  ("JAMS") under the
then existing JAMS Rules of Practice and Procedure.  Any such arbitration  shall
be conducted  in the utmost  secrecy.  Nothing in this  paragraph is intended to
prevent either you or the Company from obtaining  injunctive  relief in court to
prevent irreparable harm pending the conclusion of any such arbitration.

         17. MISCELLANEOUS.  This Agreement, including Exhibits A, B (as amended
herein),  C, D, and E together  constitute  the  complete,  final and  exclusive
embodiment  of the entire  agreement  between you and the Company with regard to
this  subject  matter.  It is entered  into  without  reliance on any promise or
representation,  written or oral, other than those expressly  contained  herein,
and it supersedes any other such promises,  warranties or representations.  This
Agreement may not be


<PAGE>

James L. Tyree
July 18, 1996
Page 5

modified or amended except in a writing signed by both you and a duly authorized
officer  of  the  Company.   This  Agreement  shall  bind  the  heirs,  personal
representatives,  successors and assigns of both you and the Company,  and inure
to the benefit of both you and the Company, their heirs, successors and assigns.
If any provision of this Agreement is determined to be invalid or unenforceable,
in whole or in part, this  determination  will not affect any other provision of
this  Agreement and the provision in question  shall be modified by the court or
arbitrator so as to be rendered  enforceable.  This Agreement shall be deemed to
have been entered into and shall be construed  and enforced in  accordance  with
the laws of the State of  California  as  applied  to  contracts  made and to be
performed entirely within California.

         If this  Agreement is acceptable  to you,  please sign below and on the
attached Employee  Agreement and Release,  which is part of this Agreement,  and
return the originals of both to me.

         Please accept my best wishes for success in your future endeavors.

                                                    Sincerely,

                                                    SUGEN, INC.


                                                    By:  /s/ Stephen Evans-Freke
                                                       -------------------------
                                                             Stephen Evans-Freke



                                                    AGREED:



                                                         /s/ James L. Tyree
                                                       -------------------------
                                                             James L. Tyree





Exhibit A - Stock Option Status Report
Exhibit B - Loan Agreement, including Exhibits
Exhibit C - Lien Release (Full Reconveyance)
Exhibit D - Proprietary Information and Inventions Agreement
Exhibit E - Employee Agreement and Release




<PAGE>



<TABLE>
                                                     EXHIBIT A

                                         OPTION STATUS AS OF JUNE 6, 1996



<CAPTION>
                                                                                       Vesting
Grant                     Date of         Total                  Currently             Through           Total
Number                      Grant       Granted       Price         Vested         June 6,1997        Canceled
- ------                      -----       -------       -----         ------         -----------        --------

<C>        <C>            <C>            <C>        <C>             <C>                 <C>             <C>   
258/260    (1),(3)        6/17/94        93,332     $6.0000         51,332              18,667          23,333

261        (2),(3)        6/17/94        53,333      6.0000         13,333                   -          40,000

296        (3)            2/23/95        50,000      6.5625         15,625              12,500          21,875

SR-002     (2),(4)        7/26/95        90,000      8.1250              -                   -          90,000

580        (1),(3)        1/18/96        30,000     11.7500          1,875               7,500          20,625
                                      ----------                -----------        -----------        ---------
                                        316,665                     82,165              38,667         195,833
                                      ==========                ===========        ===========        =========
<FN>

Note:

(1) Total Options Granted include both ISOs and NSOs (2) Contingent options vest
based on certain criteri
(3) Option granted under the 1992 Stock Option Plan
(4) Option granted under the  Long-Term  Objectives Stock Option Plan for Senior
Management

1994 Grants have been restated to effect the  September  1994 3.75-for-1 reverse
stock split
</FN>
</TABLE>

<PAGE>


                                    EXHIBIT B

                                 LOAN AGREEMENT


This Exhibit B is  incorporated  by reference to Exhibit 10.38 filed in response
to Item 6 "Exhibits"  of the  Registrant's  Form 10-Q for the quarter ended June
30, 1995.



<PAGE>


- ----------------------------------------------------------------------------
                                                             ALL.
                                                           -----------------
                                                             PTN.
- ----------------------------------------------------------------------------



          RECORDING REQUESTED BY


        AND WHEN RECORDED MAIL TO

    Name   -                         -

  Street     Sugen, Inc.
  Address    515 Galveston Drive
             Redwood City, CA  94063
  City &                                SPACE ABOVE THIS LINE FOR RECORDER'S USE
  State   -                          -
           ---------------------------------------------------------------------


TO 430.1 CA (7-84)              Full Reconveyance
- --------------------------------------------------------------------------------
SUGEN, INC., as duly appointed Trustee under Deed of Trust hereinafter  referred
to, having received from holder of the obligations  thereunder a written request
to reconvey,  reciting  that the  promissory  notes secured by the Deed of Trust
will  become  unsecured  obligations,   and  said  Deed  of  Trust  having  been
surrendered to said Trustee,  does hereby  RECONVEY,  without  warranty,  to the
person  or  persons  legally  entitled  thereto,  the  estate  now  held  by  it
thereunder. Said Deed of Trust was  executed  by JAMES L. TYREE and RENEE TYREE,
husband and wife

                                                                       Trustors,

         and recorded in the official  records of San Mateo County,  California,
as follows:

REC.  June 12, 1996     AS INSTR. NO.  96-070557       IN BOOK/REEL  N/A
      -------------                    ---------                     -----------

DESC.

LOT 13,  AS SHOWN ON THAT  CERTAIN  MAP  ENTITLED,  "MAP OF  HILLSBOROUGH  PARK,
HILLSBOROUGH SAN MATEO COUNTY,  CALIFORNIA"  FILED IN THE OFFICE OF THE RECORDER
OF THE COUNTY OF SAN MATEO,  STATE OF CALIFORNIA ON APRIL 14, 1924 IN BOOK 11 OF
MAPS AT PAGE(S) 58 TO 61 INCLUSIVE.

Dated __________________________________    ____________________________________

================================================================================

STATE OF _______________________________             )
                                                     ) ss.
COUNTY OF _____________________________              )


On _______________________, 19___, before me, ________________________________ ,
personally appeared _______________________________________________,

         |_|      personally known to me
                  -or-
         |_|      proved to me on the basis of satisfactory evidence
                  to be the  person(s)  whose name(s)  is/are  subscribed to the
                  within  instrument  and  acknowledged  to me that  he/she/they
                  executed the same in his/her/their  authorized  capacity(ies),
                  and that by  his/her/their  signature(s) on the instrument the
                  person(s)  or the entity  upon  behalf of which the  person(s)
                  acted, executed the instrument.

                                            Witness my hand and official seal.


                   -------------------------------------------------------------
                   Signature of the Notary           CAPACITY CLAIMED BY SIGNER
Though  statute does not require the Notary to fill in the data below,  doing so
may prove invaluable to persons relying on the document.

|_|  Individual
|_|  Corporate Officer(s)

     ---------------------------------------------------------------------------
|_|  Partner(s)   |_|  Limited
                  |_|  General
|_|  Attorney-in-Fact
|_|  Trustee(s)
|_|  Guardian/Conservator
|_|  Other: ____________________________________________________________________

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

SIGNER IS REPRESENTING:
Name of person(s) or entity(ies)


- --------------------------------------------------------------------------------
_________________________________________________________ This  certificate must
be attached to the document described at right:


(C)1993 National Notary Association, Canoga Park, CATitle or Type of Document:

- --------------------------------------------------------------------------------
Number of Pages:____________________ Date of Document: _________________________
Signer(s) other than named above: ______________________________________________
================================================================================
                                   EXHIBIT C
                                     1 of 2


<PAGE>



Title or Trust No.
Chicago Title #500309
Escrow of Loan No.

WHEN RECORDED MAIL TO:

Sugen, Inc.
515 Galveston Drive
Redwood City, CA  94063


                                        SPACE ABOVE THIS LINE FOR RECORDER'S USE
- --------------------------------------------------------------------------------

                             SUBSTITUTION OF TRUSTEE


WHEREAS,  JAMES L. TYREE and RENEE  TYREE,  husband  and wife were the  original
Trustors,  North American Title Company,  was the original  Trustee,  and SUGEN,
INC. was the  Beneficiary  under that  certain  Deed of Trust,  dated August 29,
1994,  recorded June 12, 1996, as Document No.  96-070557 of Official Records of
San Mateo County, California (the "Deed of Trust");

WHEREAS,  the undersigned desires to substitute a new Trustee under said Deed of
Trust in the place and stead of North American Title Company.

WHEREAS,  the Deed of Trust encumbers the following described property,  located
in the County of San Mateo, State of California:

LOT 13,  AS SHOWN ON THAT  CERTAIN  MAP  ENTITLED,  "MAP OF  HILLSBOROUGH  PARK,
HILLSBOROUGH SAN MATEO COUNTY,  CALIFORNIA"  FILED IN THE OFFICE OF THE RECORDER
OF THE COUNTY OF SAN MATEO,  STATE OF CALIFORNIA ON APRIL 14, 1924 IN BOOK 11 OF
MAPS AT PAGE(S) 58 TO 61 INCLUSIVE.


NOW  THEREFORE,  the  undersigned  hereby  substitutes  itself,  SUGEN,  Inc., a
Delaware  corporation,  as Trustee under said Deed of Trust. The address of said
Trustee is 515 Galveston Drive, Redwood City, CA 94063.


SUGEN, Inc.



By:________________________________________________
Name:______________________________________________
Title:_____________________________________________

Dated:_____________________________________________
<TABLE>
<CAPTION>

==============================================================================================================================
<S>                                                  <C>                               <C>
STATE OF CALIFORNIA                                  )                                     CAPACITY CLAIMED BY SIGNER
                                                     ) ss.                             Though statute does not require the
COUNTY OF __________________________                 )                                 Notary to fill in the data below, doing 
                                                                                       so may prove invaluable to persons 
On _________________________, 19___, before me, __________________________________,    relying on the document.
personally appeared ___________________________________,
                                                                                       |_|  Individual
         |_|  personally known to me                                                   |_|  Corporate Officer(s)
              -or-                                                                          __________________________________
         |_|  proved to me on the basis of satisfactory evidence                       |_|  Partner(s)   |_|  Limited
                  to be the person whose name is subscribed to within the                                 |_|  General
                  instrument and acknowledged to me that he executed the same in       |_|  Attorney-in-Fact
                  his authorized capacity, and that by his signature on the            |_|  Trustee(s)
                  instrument, the person or the entity upon behalf of which the        |_|  Guardian/Conservator
                  person acted, executed the instrument.                               |_|  Other:____________________________
                                                                                            __________________________________
                                            Witness my hand and official seal.
                                                                                        SIGNER IS REPRESENTING:
                                                                                        Name of person(s) or entity(ies)

                                            --------------------------------------      --------------------------------------
                                            Signature of the Notary                     --------------------------------------

- ------------------------------------------------------------------------------------------------------------------------------
This certificate must be attached to the                Title or Type of Document:____________________________________________
document described at right:                            Number of Pages:_______________ Date of Document:_____________________
                                                        Signer(s) other than named above:_____________________________________

(C)1993 National Notary Association, Canoga Park, CA
==============================================================================================================================
</TABLE>



<PAGE>



                                    EXHIBIT D

                          EMPLOYEE'S SECRECY AGREEMENT
                                    CLERICAL


I  recognize  that  SUGEN  INC.,  a  Delaware  corporation,  together  with  its
subsidiaries  (hereinafter  collectively  called the  "Company") is engaged in a
continuous  program of research,  development,  and  production  respecting  its
business,  present  and  future,  including  fields  generally  related  to  its
business.

I understand that:

         1. My employment creates a relationship of confidence and trust between
me and the Company with respect to any information:

                  (a)  Applicable to the business of the Company; or

                  (b)  Applicable  to the  business of any client or customer of
the  Company,  which may be made known to me by the  Company or by any client or
customer of Company, or learned by me during the period of my employment.

         2. The Company possesses and will continue to possess  information that
has been  created,  discovered,  developed,  or  otherwise  become  known to the
Company   (including  without  limitation   information   created,   discovered,
developed,  or made  known by me  during  the  period  of or  arising  out of my
employment by the Company) and/or in which property rights have been assigned or
otherwise conveyed to the Company, which information has commercial value in the
business in which the Company is engaged. All of the aforementioned  information
is hereinafter called "Proprietary Information." By way of illustration, but not
limitation, Proprietary Information includes trade secrets, processes, formulas,
data  and  know-how,  improvements,  inventions,  techniques,  marketing  plans,
strategies, forecasts, and customer lists.

In consideration of my employment or continued  employment,  as the case may be,
and the compensation received by me from the Company from time to time, I hereby
agree as follows:

         1.  All  Proprietary  Information  shall be the  sole  property  of the
Company and its assigns, and the Company and its assigns shall be the sole owner
of all patents and other rights in connection therewith.  I hereby assign to the
Company any rights I may have or acquire in such Proprietary Information. At all
times,  both during my  employment by the Company and after its  termination,  I
will keep in confidence and trust all  Proprietary  Information,  and I will not
use or disclose any Proprietary  Information or anything  relating to it without
the written  consent of the Company,  except as may be necessary in the ordinary
course of performing my duties as an employee of the Company.

         2. I agree that  during the period of my  employment  by the  Company I
will  not,  without  the  Company's  express  written  consent,  engage  in  any
employment  or activity  other than for the Company in any business in which the
Company is now or may hereafter become engaged.  In the event of the termination
of my employment by me or by the Company for any



<PAGE>


reason,  I will  deliver to the  Company  all  documents  and data of any nature
pertaining to my work with the Company and I will not take with me any documents
or data of any description or any reproduction of any description  containing or
pertaining to any Proprietary Information.

         3. I represent  that my  performance of all the terms of this Agreement
as an employee of the Company does not and will not breach any agreement to keep
in confidence  proprietary  information acquired by me in confidence or in trust
prior to my  employment by the Company.  I have not entered into,  and I agree I
will not enter into, any agreement either written or oral in conflict herewith.

         4.  This  Agreement  shall  be  effective  as of  the  first  day of my
employment by the Company, namely:_____________________________________________.

         5. This  Agreement  shall be  binding  upon me,  my  heirs,  executors,
assigns,  and  administrators  and shall inure to the benefit of the Company its
successors, and assigns.

Accepted and Agreed To:


By:   /s/ James L. Tyree
      ---------------------------

Date:  6/6/94
       -------------


                                       2.

<PAGE>


                                    EXHIBIT E

                         EMPLOYEE AGREEMENT AND RELEASE

         Except as  otherwise  set forth in this  Agreement,  I hereby  release,
acquit and forever  discharge  the Company,  its parents and  subsidiaries,  and
their officers, directors, agents, servants, employees, attorneys, shareholders,
successors, assigns and affiliates, of and from any and all claims, liabilities,
demands, causes of action, costs, expenses, attorneys fees, damages, indemnities
and obligations of every kind and nature,  in law, equity,  or otherwise,  known
and unknown, suspected and unsuspected,  disclosed and undisclosed,  arising out
of or in any way  related  to  agreements,  events,  acts or conduct at any time
prior to and including the execution date of this  Agreement,  including but not
limited to: all such claims and demands directly or indirectly arising out of or
in any way connected with my employment  with the Company or the  termination of
that  employment;  claims or demands  related to salary,  bonuses,  commissions,
stock, stock options, or any other ownership interests in the Company,  vacation
pay, fringe benefits,  expense reimbursements,  severance pay, or any other form
of  compensation;  claims  pursuant to the Offer Letter;  claims pursuant to the
Deferred Compensation Agreement;  claims pursuant to any federal, state or local
law,  statute,  or cause of action  including,  but not  limited to, the federal
Civil Rights Act of 1964, as amended;  the federal  Americans with  Disabilities
Act of 1990;  the federal  Age  Discrimination  in  Employment  Act of 1967,  as
amended  ("ADEA");  the California  Fair Employment and Housing Act, as amended;
tort law; contract law; wrongful discharge;  discrimination;  harassment; fraud;
defamation; emotional distress; and breach of the implied covenant of good faith
and fair dealing.

         I acknowledge that I am knowingly and voluntarily waiving and releasing
any rights I may have under  ADEA.  I also  acknowledge  that the  consideration
given  for the  waiver  and  release  in the  preceding  paragraph  hereof is in
addition  to  anything  of value  to which I was  already  entitled.  I  further
acknowledge  that I have been advised by this writing,  as required by the ADEA,
that:  (a) my waiver and  release do not apply to any rights or claims  that may
arise  after  the  execution  date of this  Agreement;  (b) I have the  right to
consult  with  an  attorney  prior  to  executing  this  Agreement;  (c) I  have
twenty-one  (21) days to  consider  this  Agreement  (although  I may  choose to
voluntarily execute this Agreement earlier); (d) I have seven (7) days following
the execution of this Agreement by the parties to revoke the Agreement;  and (e)
this Agreement  shall not be effective  until the date upon which the revocation
period has  expired,  which  shall be the eighth  day after  this  Agreement  is
executed by me ("Effective Date").

         In giving this release,  which includes  claims which may be unknown to
me at present, I acknowledge that I have read and understand Section 1542 of the
California Civil Code which reads as follows: "A general release does not extend
to claims which the  creditor  does not know or suspect to exist in his favor at
the time of executing  the release,  which if known by him must have  materially
affected  his  settlement  with  the  debtor."  I  hereby  expressly  waive  and
relinquish  all  rights  and  benefits  under  that  section  and any law of any
jurisdiction  of similar  effect with  respect to my release of any claims I may
have against the Company.


                                                     By:   /s/ James L. Tyree
                                                        ------------------------
                                                               James L. Tyree

                                                     Date:     07/18/96
                                                           --------------------


<TABLE> <S> <C>


<ARTICLE>                     5
<LEGEND>
            THE SCHEDULE CONTAINS SUMMARY FINANCIAL  INFORMATION  EXTRACTED FROM
            THE  COMPANY'S  FORM 10-Q FOR THE THREE MONTHS ENDED  SEPTEMBER  30,
            1996 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
            STATEMENTS.
                
</LEGEND>
<MULTIPLIER>                                   1,000
       
<S>                             <C>
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                              DEC-31-1996
<PERIOD-START>                                 JAN-01-1996
<PERIOD-END>                                   SEP-30-1996
<CASH>                                           4,249
<SECURITIES>                                    29,127
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                                34,216
<PP&E>                                           7,793
<DEPRECIATION>                                   3,729
<TOTAL-ASSETS>                                  39,651
<CURRENT-LIABILITIES>                            8,691
<BONDS>                                          3,250
<COMMON>                                        81,382
                                0
                                          0
<OTHER-SE>                                     (53,672)
<TOTAL-LIABILITY-AND-EQUITY>                    39,651
<SALES>                                              0
<TOTAL-REVENUES>                                10,338
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                                21,379
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 521
<INCOME-PRETAX>                                (13,895)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                            (13,895)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   (13,895)
<EPS-PRIMARY>                                    (1.32)
<EPS-DILUTED>                                    (1.32)
        


</TABLE>


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