***TEXT OMITTED AND FILED SEPARATELY
                                                CONFIDENTIAL TREATMENT REQUESTED
                                            UNDER 17 C.F.R. SS.SS. 200.80(B)(4),
                                                            200.83 AND 240.24B-2


                                                            Customer Number 1036

                              AMENDED AND RESTATED
                             MASTER LEASE AGREEMENT


Lessor:           TRANSAMERICA BUSINESS CREDIT CORPORATION
                  Riverway II
                  West Office Tower
                  9399 West Higgins Road
                  Rosemont, Illinois  60018


Lessee:           SUGEN, INC.
                  515 Galveston Drive
                  Redwood City, California 94063-4720


The lessor  pursuant to this Master Lease  Agreement  ("Agreement")  dated as of
March 28, 1997, as amended on November 12, 1997, is Transamerica Business Credit
Corporation ("Lessor"). All equipment,  software ("Software"),  items designated
as  tenant  improvements  on the  applicable  schedule  ("Tenant  Improvements")
together with all present and future additions, parts, accessories, attachments,
substitutions,  repairs, improvements and replacements thereof or thereto, which
are the subject of a Lease (as defined in the next  sentence)  shall be referred
to as  "Equipment".  Simultaneous  with  the  execution  and  delivery  of  this
Agreement,  the parties are entering into one or more Lease  Schedules  (each, a
"Schedule") which refer to and incorporate by reference this Agreement,  each of
which constitutes a lease (each, a "Lease") for the Equipment specified therein.
Additional  details  pertaining  to each Lease are  specified in the  applicable
Schedule. Each Schedule that the parties hereafter enter into shall constitute a
Lease.  Lessor has no  obligation to enter into any  additional  leases with, or
extend any future financing to, Lessee other than stated in Paragraph 1 below.

         1. LEASE.  Subject to and upon all of the terms and  conditions of this
Agreement and each Schedule,  Lessor hereby agrees to lease to Lessee and Lessee
hereby  agrees to lease from  Lessor the  Equipment  for the Term (as defined in
Paragraph  2  below)  thereof.  The  timing  and  financial  scope  of  Lessor's
obligation  to enter  into  Leases  hereunder  are  limited  as set forth in the
Commitment Letters executed by Lessor and Lessee, dated as of March 20, 1997 and
November  5, 1997 and  attached  hereto as  Exhibits A and B and any  Commitment
Letters hereafter  executed by Lessor and Lessee and attached hereto as Exhibits
(the "Commitment Letters").

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         2.  TERM.  Each  Lease  shall be  effective  and the term of each Lease
("Term")  shall  commence on the  commencement  date specified in the applicable
Schedule which date shall not be prior to delivery,  acceptance and funding and,
unless sooner terminated (as hereinafter  provided),  shall expire at the end of
the term specified in such Schedule;  provided, however, that obligations due to
be  performed  by Lessee  during  the Term shall  continue  until they have been
performed  in full.  Schedules  will only be executed  after the delivery of the
Equipment to Lessee or upon  completion of deliveries of items of such Equipment
with aggregate cost of not less than $[...***...].

         3. RENT.  Lessee shall pay as rent to Lessor,  for use of the Equipment
during the Term or Renewal Term (as defined in  Paragraph  8),  rental  payments
equal to the sum of all rental payments including, without limitation,  security
deposits,  advance  rents and  interim  rents  payable in the amounts and on the
dates specified in the applicable Schedule ("Rent"). If any Rent or other amount
payable by Lessee is not paid  within ten days after the day on which it becomes
payable,  Lessee  will pay on  demand,  as a late  charge,  an  amount  equal to
[...***...] or other amount but only to the extent  permitted by applicable law.
All  payments  provided  for herein  shall be  payable to Lessor at its  address
specified above, or at any other place designated by Lessor. Lessee's commitment
fees paid pursuant to the Commitment Letters shall be applied towards the second
month's  rent (after  deductions  for  expenses  under  paragraph  23) under the
initial  Schedules  and each  monthly  rental  payment  thereafter  until  fully
applied.

         4. LEASE NOT CANCELABLE; LESSEE'S OBLIGATIONS ABSOLUTE. No Lease may be
canceled or terminated  except as expressly  provided herein.  So long as Lessor
has not wrongfully  interfered  with Lessee's quiet  enjoyment of the Equipment,
Lessee's  obligation  to pay all Rent due or to become  due  hereunder  shall be
absolute  and  unconditional  and shall not be subject to any delay,  reduction,
set-off,  defense,   counterclaim  or  recoupment  for  any  reason  whatsoever,
including  any  failure  of  the  Equipment  or  any   representations   by  the
manufacturer or the vendor thereof.  If the Equipment is unsatisfactory  for any
reason,  Lessee  shall make any claim  solely  against the  manufacturer  or the
vendor thereof and shall,  nevertheless,  pay Lessor all Rent payable hereunder.

         5.  SELECTION  AND USE OF  EQUIPMENT.  Lessee  agrees  that it shall be
responsible for the selection,  use of, and results obtained from, the Equipment
and any other associated equipment or services.

         6. WARRANTIES.  LESSOR MAKES NO REPRESENTATION OR WARRANTY,  EXPRESS OR
IMPLIED, AS TO ANY MATTER WHATSOEVER,  INCLUDING, WITHOUT LIMITATION, THE DESIGN
OR CONDITION OF THE EQUIPMENT OR ITS  MERCHANTABILITY,  SUITABILITY,  QUALITY OR
FITNESS FOR A PARTICULAR PURPOSE, AND HEREBY DISCLAIMS ANY SUCH WARRANTY. LESSEE
SPECIFICALLY  WAIVES ALL RIGHTS TO MAKE A CLAIM AGAINST LESSOR FOR BREACH OF ANY
WARRANTY  WHATSOEVER.  ONCE ACCEPTED BY LESSEE,  LESSEE LEASES THE EQUIPMENT "AS
IS." IN NO EVENT SHALL LESSOR HAVE ANY LIABILITY  FOR, NOR SHALL LESSEE HAVE ANY
REMEDY AGAINST LESSOR FOR, ANY LIABILITY,  CLAIM, LOSS, DAMAGE OR EXPENSE CAUSED
DIRECTLY OR INDIRECTLY BY THE EQUIPMENT OR ANY  DEFICIENCY OR DEFECT  THEREOF OR
THE OPERATION,  MAINTENANCE OR REPAIR  THEREOF OR ANY  CONSEQUENTIAL  DAMAGES AS
THAT TERM IS USED IN SECTION  2-719(3) OF THE MODEL UNIFORM  COMMERCIAL CODE, AS
AMENDED FROM TIME TO TIME ("UCC"). Lessor grants to Lessee, for the sole purpose
of prosecuting a claim or receiving benefits under the warranty, the benefits of
any and all warranties  made available by the  manufacturer or the vendor of the
Equipment to the extent assignable.


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         7. DELIVERY.  Lessor hereby  appoints  Lessee as Lessor's agent for the
sole and limited purpose of accepting delivery of the Equipment from each vendor
thereof.  Lessee shall pay any and all delivery and installation charges. Lessor
shall not be liable to Lessee for any delay in, or failure  of,  delivery of the
Equipment.

         8.  RENEWAL.  So long as no Event of Default or event  which,  with the
giving of notice,  the passage of time,  or both,  would  constitute an Event of
Default,  shall have  occurred and be  continuing,  or the Lessee shall not have
exercised  its  purchase  option under  Paragraph 9 hereof,  Lessee may elect to
renew upon 60 days prior  written  notice to Lessor  each Lease on the terms and
conditions  of this  Agreement or as set forth in the  applicable  Schedule (the
"Renewal Term"); provided,  however, that if Lessee elects to renew, obligations
due to be performed by the Lessee during the Renewal Term shall  continue  until
they have been performed in full.  The monthly  rental  payments for the Renewal
Term shall be as set forth in the applicable  Schedule.

         9. PURCHASE OPTION. So long as no Event of Default or event which, with
the giving of notice, the passage of time, or both, would constitute an Event of
Default, shall have occurred and be continuing, Lessee may purchase all, but not
less  than  all,  the  Equipment  covered  by the  applicable  Lease on the date
specified  therefor in the applicable  Schedule  ("Purchase Date"). The purchase
price for such Equipment shall be set forth in the applicable Schedule.  So long
as no Event of Default or event which, with the giving of notice, the passage of
time, or both, would constitute an Event of Default,  shall have occurred and be
continuing,  Lessee  may  purchase  all,  but not less than all,  the  Equipment
covered by the  applicable  Schedule by the last date of the  Renewal  Term (the
"Alternative  Purchase Date") at a purchase price equal to  [...***...].  On the
Purchase  Date or the  Alternative  Purchase  Date,  as the case may be, for any
Equipment,  Lessee shall pay to Lessor the  purchase  price,  together  with all
sales and other taxes  applicable to the transfer of the Equipment and any other
amount payable and arising hereunder,  in immediately available funds, whereupon
Lessor  shall  transfer  to Lessee,  without  recourse  or warranty of any kind,
express or implied,  all of Lessor's  right,  title and  interest in and to such
Equipment  on an "As Is, Where Is" basis and file UCC-3  termination  statements
upon reasonable request by Lessee.

         10. OWNERSHIP;  INSPECTION; MARKING; FINANCING STATEMENTS. Lessee shall
affix to the Equipment, other than the Tenant Improvements,  any labels supplied
by Lessor indicating ownership of such Equipment.  The Equipment is and shall be
the sole  property  of Lessor.  Lessee  shall have no right,  title or  interest
therein,  except as lessee under a Lease.  Other than Tenant  Improvements,  the
Equipment  is and shall at all times be and remain  personal  property and shall
not become a fixture.  Lessee shall obtain and record such  instruments and take
such steps as may be necessary to prevent any person from  acquiring  any rights
in the  Equipment,  other  than in the  Tenant  Improvements,  by  reason of the
Equipment  being  claimed or deemed to be real  property.  Lessee shall make the
Equipment and its  maintenance  records  available  for  inspection by Lessor at
reasonable times and upon reasonable notice. Lessee shall execute and deliver to
Lessor for filing any UCC financing  statements or similar  documents Lessor may
reasonably request.

         11. EQUIPMENT USE. Lessee agrees that the Equipment will be operated by
competent,  qualified  personnel in connection  with  Lessee's  business for the
purpose for which the Equipment was designed and in accordance  with  applicable
operating instructions,  laws and government regulations,  and that Lessee shall
use all  reasonable  precautions to prevent loss or damage to the Equipment from
fire and other hazards.  Lessee shall procure and maintain in effect all orders,
licenses,  certificates,  permits,  approvals and consents  required by federal,
state  or  local  laws or by any  governmental  body,  agency  or  authority  in
connection with the delivery,  installation, use and operation

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of the Equipment.

         12. MAINTENANCE.  Lessee, at its sole cost and expense,  shall keep the
Equipment  in  a  suitable   environment  as  specified  by  the  manufacturer's
guidelines or the  equivalent  and meet all  recertification  requirements,  and
shall  maintain  the  Equipment  in its original  condition  and working  order,
ordinary wear and tear  excepted.  At the reasonable  request of Lessor,  Lessee
shall furnish all proof of maintenance.

         13. ALTERATION;  MODIFICATIONS;  PARTS.  Lessee may alter or modify the
Equipment only with the prior written consent of Lessor. Any alteration shall be
removed  and the  Equipment  restored  to its  normal,  unaltered  condition  at
Lessee's expense (without damaging the Equipment's  originally intended function
or its value) prior to its return to Lessor.  Any part  installed in  connection
with  warranty or  maintenance  service or which cannot be removed in accordance
with the  preceding  sentence  shall be the  property of Lessor.

         14.  RETURN OF  EQUIPMENT.  Except for  Equipment  that has  suffered a
Casualty  Loss (as  defined in  Paragraph  15 below) and is not  required  to be
repaired  pursuant  to  Paragraph  15 below or  Equipment  purchased  by  Lessee
pursuant to Paragraph 9 above,  upon  expiration of the Renewal Term of a Lease,
or upon demand by Lessor  pursuant to Paragraph 22 below,  Lessee shall  contact
Lessor for shipping  instructions and, at Lessee's own risk,  immediately return
the Equipment,  freight prepaid,  to a location in the continental United States
specified by Lessor.  At the time of such return to Lessor,  the Equipment shall
(i) be in the operating order,  repair and condition as required by or specified
in the original  specifications  and warranties of each  manufacturer and vendor
thereof,   ordinary  wear  and  tear  excepted,  and  meet  all  recertification
requirements  and (ii) be capable of being promptly  assembled and operated by a
third party purchaser or third party lessee without further repair, replacement,
alterations or  improvements,  and in accordance and compliance with any and all
statutes, laws, ordinances,  rules and regulations of any governmental authority
or any political  subdivision thereof applicable to the use and operation of the
Equipment.  Except as  otherwise  provided  under  Paragraph 9 hereof,  at least
thirty days before the expiration of the Renewal Term,  Lessee shall give Lessor
notice of its intent to return the  Equipment at the end of such  Renewal  Term.
During the  thirty-day  period prior to the end of the Renewal Term,  Lessor and
its  prospective  purchasers  or  lessees  shall  have,  upon not less  than two
business days' prior notice to Lessee and during normal  business  hours,  or at
any time and without  prior notice upon the  occurrence  and  continuance  of an
Event of Default,  the right of access to the premises on which the Equipment is
located to  inspect  the  Equipment,  and Lessee  shall  cooperate  in all other
respects with Lessor's  remarketing  of the  Equipment.  The  provisions of this
Paragraph 14 are of the essence of the Lease,  and upon application to any court
of equity having  jurisdiction  in the  premises,  Lessor shall be entitled to a
decree against Lessee requiring specific  performance of the covenants of Lessee
set forth in this  Paragraph  14. If Lessee fails to return the  Equipment  when
required,  the terms and conditions of the Lease shall continue to be applicable
and Lessee shall continue to pay Rent until the Equipment is received by Lessor.

         15. CASUALTY INSURANCE;  LOSS OR DAMAGE.  Lessee will maintain,  at its
own expense,  liability and property damage insurance relating to the Equipment,
insuring  against such risks as are  customarily  insured against on the type of
equipment  leased  hereunder  by  businesses  in which Lessee is engaged in such
amounts,  in such form,  and with  insurers  satisfactory  to Lessor;  provided,
however,  that the amount of insurance  against damage or loss shall not be less
than the greater of (a) the [...***...] of the Equipment and (b) the [...***...]
of  the  Equipment  specified  in  the  applicable  Schedule  [...***...].  Each
liability   insurance   policy  shall  provide  coverage   (including,   without
limitation,  personal injury  coverage) of not less than  $[...***...]  for each
occurrence,  and shall name Lessor as an

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additional  insured;  and each property  damage policy shall name Lessor as sole
loss payee and all policies shall contain a clause requiring the insurer to give
Lessor at least thirty days prior written  notice of any alteration in the terms
or cancellation of the policy.  Lessee shall furnish an insurance certificate or
other evidence satisfactory to Lessor that the required insurance coverage is in
effect; provided,  however, Lessor shall have no duty to ascertain the existence
of or to examine the insurance  certificates or policies to advise Lessee if the
insurance  coverage does not comply with the requirements of this Paragraph.  If
Lessee fails to insure the  Equipment  as required,  Lessor shall have the right
but not the obligation to obtain such  insurance,  and the cost of the insurance
shall be for the  account  of Lessee  due as part of the next due  Rent.  Lessee
consents to Lessor's release,  upon its failure to obtain appropriate  insurance
coverage,  of any and all information necessary to obtain insurance with respect
to the Equipment or Lessor's interest  therein.

         Until the  Equipment  is returned to and received by Lessor as provided
in Paragraph 14 above, Lessee shall bear the entire risk of theft or destruction
of, or damage to, the Equipment including, without limitation, any condemnation,
seizure or requisition of title or use ("Casualty Loss"). No Casualty Loss shall
relieve Lessee from its obligations to pay Rent except as provided in clause (b)
below.  When any Casualty Loss occurs,  Lessee shall  immediately  notify Lessor
and, at the option of Lessor,  shall  promptly (a) place such  Equipment in good
repair and working order;  or (b) pay Lessor an amount equal to the  [...***...]
of such  Equipment  and all other  amounts  (excluding  Rent)  payable by Lessee
hereunder, together with a late charge on such amounts at a rate per annum equal
to the [...***...]  hereunder (as reasonably determined by Lessor) from the date
of the  Casualty  Loss  through the date of payment of such  amounts,  whereupon
Lessor  shall  transfer to Lessee,  without  recourse  or  warranty  (express or
implied),  all of Lessor's interest,  if any, in and to such Equipment on an "AS
IS, WHERE IS" basis.  The proceeds of any insurance  payable with respect to the
Equipment  shall be applied,  at the option of Lessee if no Event of Default has
occurred  and is  continuing  (and  otherwise  at the option of Lessor),  either
towards  (i)  repair  of the  Equipment  or  (ii)  payment  of  any of  Lessee's
obligations    hereunder.    Lessee   hereby   appoints   Lessor   as   Lessee's
attorney-in-fact  to make claim for, receive payment of, and execute and endorse
all  documents,  checks or drafts issued with respect to any Casualty Loss under
any insurance policy relating to the Equipment.

         16.  TAXES.  Lessee shall pay when due, and  indemnify  and hold Lessor
harmless  from,  all sales,  use,  excise  and other  taxes,  charges,  and fees
(including,  without  limitation,  income,  franchise,  business and occupation,
gross receipts, licensing,  registration,  titling, personal property, stamp and
interest equalization taxes, levies, imposts, duties, charges or withholdings of
any  nature),  and if  resulting  from an act or omission of Lessee,  any fines,
penalties  or  interest  thereon,  imposed or levied by any  governmental  body,
agency or tax authority upon or in connection with the Equipment,  its purchase,
ownership,  delivery, leasing, possession, use or relocation of the Equipment or
otherwise in connection with the transactions  contemplated by each Lease or the
Rent  thereunder,  excluding  taxes on or  measured by the net income of Lessor.
Upon  request,  Lessee will  provide  proof of  payment.  Unless  Lessor  elects
otherwise,  Lessor will pay all property taxes on the Equipment for which Lessee
shall reimburse Lessor promptly upon request and proof of payment.  Lessee shall
timely  prepare and file all reports and returns  which are  required to be made
with respect to any  obligation of Lessee under this Paragraph 16. Lessee shall,
to the extent permitted by law, cause all billings of such fees, taxes,  levies,
imposts,  duties,  withholdings and governmental charges to be made to Lessor in
care of Lessee. Upon request, Lessee will provide Lessor with copies of all such
billings.  Lessee shall have the option to contest taxes  diligently and in good
faith as long as Lessee maintains  adequate  reserves for such taxes measured in
accordance with General Accepted Accounting Principles.

         17. LESSOR'S PAYMENT.  If Lessee fails to perform its obligations under

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Paragraph 15 or 16 above, or Paragraph 23 below,  Lessor shall have the right to
substitute performance, in which case, Lessee shall immediately reimburse Lessor
therefor.

         18. GENERAL  INDEMNITY.  Each Lease is a net lease.  Therefore,  Lessee
shall indemnify Lessor and its successors and assigns  against,  and hold Lessor
and its  successors  and assigns  harmless  from,  any and all claims,  actions,
damages, obligations, liabilities and all costs and expenses, including, without
limitation,  reasonable  legal fees,  incurred by Lessor or its  successors  and
assigns arising out of each Lease including,  without limitation,  the purchase,
ownership, delivery, lease, possession, maintenance, condition, use or return of
the Equipment,  or arising by operation of law,  except that Lessee shall not be
liable for any claims,  actions,  damages,  obligations  and costs and  expenses
determined by a non-appealable, final order of a court of competent jurisdiction
have  occurred  as a result of the gross  negligence  or willful  misconduct  of
Lessor or its successors and assigns.  Lessee agrees that upon written notice by
Lessor of the assertion of any claim, action, damage,  obligation,  liability or
lien, Lessee shall assume full responsibility for the defense thereof,  provided
that  Lessor's  failure to give such notice shall not limit or otherwise  affect
its  rights  hereunder  except to the  extent  Lessee  incurs a loss as a direct
result of such failure.  Any payment pursuant to this Paragraph  (except for any
payment of Rent) shall be of such amount as shall be  necessary  so that,  after
payment of any taxes required to be paid thereon by Lessor,  including  taxes on
or measured by the net income of Lessor,  the balance  will equal the amount due
hereunder.  The  provisions  of this  Paragraph  with regard to matters  arising
during a Lease shall survive the expiration or  termination  of such Lease.

         19.  ASSIGNMENT BY LESSEE.  Lessee shall not, without the prior written
consent of Lessor,  (a) assign,  transfer,  pledge or  otherwise  dispose of any
Lease or Equipment,  or any interest therein; (b) sublease or lend any Equipment
or permit it to be used by anyone  other than Lessee and its  employees  agents,
representatives,  contractors and other authorized persons, provided that Lessee
shall indemnify and hold Lessor and its successors and assigns harmless from any
liability arising under, or in connection with such persons' use or operation of
the Equipment;  or (c) move any Equipment from the location  specified for it in
the  applicable  Schedule,  except  that  Lessee may move  Equipment  to another
location  within the United States  provided that Lessee has delivered to Lessor
(A) prior written notice thereof and (B) duly executed financing  statements and
other  agreements and  instruments  (all in form and substance  satisfactory  to
Lessor)  necessary  or, in the  opinion  of the  Lessor,  desirable  to  protect
Lessor's interest in such Equipment. Notwithstanding anything to the contrary in
the immediately preceding sentence,  Lessee may keep any Equipment consisting of
motor  vehicles  or rolling  stock at any  location  in the United  States.

         20.  ASSIGNMENT  BY LESSOR.  Lessor may assign its  interest or grant a
security  interest in any Lease and the Equipment  individually or together,  in
whole or in part. If Lessee is given written notice of any such  assignment,  it
shall immediately make all payments of Rent and other amounts hereunder directly
to such  assignee.  Each such  assignee  shall  have all of the rights of Lessor
under each Lease  assigned  to it.  Lessee  shall not  assert  against  any such
assignee  any  set-off,  defense or  counterclaim  that Lessee may have  against
Lessor or any other person.  Notwithstanding  any  assignment by Lessor,  Lessor
shall not be relieved of its obligations  under any Lease, but in no event shall
Lessor be liable for any act or omission of its assignee.

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         21.  DEFAULT;  NO WAIVER.  Lessee or any guarantor of any or all of the
obligations  of Lessee  hereunder  (together with Lessee,  the "Lease  Parties")
shall be in default under each Lease upon the occurrence of any of the following
events (each, an "Event of Default"): (a) Lessee fails to pay within ten days of
when due any amount  required to be paid by Lessee under or in  connection  with
any Lease; (b) any of the Lease Parties fails to perform in any material respect
any other  provision  under or in  connection  with a Lease or  violates  in any
material  respect any of the covenants or agreements of such Lease Parties under
or in  connection  with a  Lease;  (c)  any  representation  made  or  financial
information  delivered  or  furnished  by any of the Lease  Parties  under or in
connection  with a Lease shall  prove to have been  inaccurate  in any  material
respect when made;  (d) any of the Lease  Parties  makes an  assignment  for the
benefit of  creditors,  whether  voluntary  or  involuntary,  or consents to the
appointment of a trustee or receiver, or if either shall be appointed for any of
the Lease Parties or for a substantial  part of its property without its consent
and, in the case of any such  involuntary  proceeding,  such proceeding  remains
undismissed or unstayed for forty-five days following the commencement  thereof;
(e) any petition or  proceeding  is filed by or against any of the Lease Parties
under any Federal or State  bankruptcy or insolvency code or similar law and, in
the case of any such  involuntary  petition  or  proceeding,  such  petition  or
proceeding  remains  undismissed or unstayed for  forty-five  days following the
filing or  commencement  thereof,  or any of the Lease  Parties takes any action
authorizing any such petition or proceeding;  (f) any of the Lease Parties fails
to pay when due any indebtedness for borrowed money or under  conditional  sales
or  installment  sales  contracts or similar  agreements,  leases or obligations
evidenced by bonds, debentures, notes or other similar agreements or instruments
to any creditor  (including  Lessor under any other agreement) after any and all
applicable  cure  periods  therefor  shall have  elapsed if the amount  involved
exceeds  $[...***...]  in the  aggregate;  (g) any  judgment  shall be  rendered
against any of the Lease  Parties  which shall  remain  unpaid or unstayed for a
period of sixty days;  (h) any of the Lease Parties shall  dissolve,  liquidate,
wind up or cease its business, sell or otherwise dispose of all or substantially
all of its assets;  (i) any of the Lease Parties shall amend or modify its name,
unless  such  Lease  Party  delivers  to Lessor  thirty  days  prior to any such
proposed  amendment  or  modification   written  notice  of  such  amendment  or
modification and within ten days before such amendment or modification  delivers
executed financing statements (in form and substance satisfactory to the Lessor)
provided  that  Lessee  shall have 10  business  days  after  notice to cure any
default  under this  paragraph  (i); (j) any of the Lease Parties shall merge or
consolidate  with any other  entity or make any  material  change in its capital
structure,  in each case without Lessor's prior written consent, which shall not
be unreasonably  withheld; (k) any of the Lease Parties shall suffer any loss or
suspension  of any material  license,  permit or other right or asset which loss
has a material adverse effect on Lessee's ability to perform hereunder,  or fail
generally  to pay its debts as they  mature,  or call a meeting for  purposes of
compromising  its debts; or (l) any of the Lease Parties shall deny or disaffirm
its obligations  hereunder or under any of the documents delivered in connection
herewith.

         22.  REMEDIES.  Upon the  occurrence  and  continuation  of an Event of
Default for ten days after notice for a payment  Event of Default and for thirty
days after notice for all other Events of Default,  Lessor shall have the right,
in its sole discretion,  to exercise any one or more of the following  remedies:
(a)  terminate  each Lease;  (b) declare any and all Rent and other amounts then
due and any and all Rent and other  amounts  to  become  due  under  each  Lease
(collectively,  the "Lease  Obligations")  immediately due and payable; (c) take
possession of any or all items of Equipment,  wherever located,  without demand,
notice,  court order or other process of law, and without liability for entry to
Lessee's premises, for damage to Lessee's property or otherwise; (d) demand that
Lessee  immediately  return any or all  Equipment to Lessor in  accordance  with
Paragraph 14 above,  and, for each day that Lessee shall fail to return any item
of  Equipment,  Lessor may demand an amount  equal to the Rent  payable for such
Equipment in accordance  with Paragraph 14 above;  (e) lease,  sell or otherwise
dispose of the Equipment in a commercially  reasonable  manner,  with or without
notice and on public or private bid; (f) recover the

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following amounts from the Lessee (as damages,  including reimbursement of costs
and expenses,  liquidated for all purposes and not as a penalty):  (i) all costs
and  expenses  of  Lessor  reimbursable  to  it  hereunder,  including,  without
limitation,  expenses of disposition of the Equipment, reasonable legal fees and
all other amounts  specified in Paragraph 23 below;  (ii) an amount equal to the
sum of (A) any accrued and unpaid Rent  through the later of (1) the date of the
applicable  default or (2) the date that Lessor has obtained  possession  of the
Equipment  or such  other  date  as  Lessee  has  made an  effective  tender  of
possession  of the  Equipment to Lessor (the  "Default  Date") and (B) if Lessor
resells or re-lets the Equipment, Rent at the periodic rate provided for in each
Lease for the additional  period that it takes Lessor to resell or re-let all of
the Equipment; (iii) the present value of all future Rent reserved in the Leases
and  contracted to be paid over the unexpired  Term of the Leases  discounted at
[...***...]   simple  interest  per  annum;   (iv)  the  present  value  of  the
reversionary  value of the  Equipment  as of the  expiration  of the Term of the
applicable  Lease  as  set  forth  on  the  applicable  Schedule  discounted  at
[...***...]  simple interest;  and (v) any  indebtedness for Lessee's  indemnity
under Paragraph 18 above,  plus a late charge at the rate specified in Paragraph
3 above,  less the amount received by Lessor, if any, upon sale or re-let of the
Equipment;  and (g)  exercise  any other  right or remedy to recover  damages or
enforce the terms of the Leases. Upon the occurrence and continuance of an Event
of Default or an event  which with the giving of notice or the  passage of time,
or both,  would  result in an Event of  Default,  Lessor  shall  have the right,
whether or not Lessor has made any demand or the obligations of Lessee hereunder
have matured,  to  appropriate  and apply to the payment of the  obligations  of
Lessee hereunder all security  deposits and other deposits  (general or special,
time or  demand,  provisional  or  final)  now or  hereafter  held by and  other
indebtedness or property now or hereafter owing by Lessor to Lessee.  Lessor may
pursue any other rights or remedies  available  at law or in equity,  including,
without limitation, rights or remedies seeking damages, specific performance and
injunctive  relief.  Any  failure of Lessor to  require  strict  performance  by
Lessee,  or any  waiver  by  Lessor  of any  provision  hereunder  or under  any
Schedule,  shall not be  construed as a consent or waiver of any other breach of
the same or of any other  provision.  Any  amendment or waiver of any  provision
hereof or under any Schedule or consent to any  departure by Lessee  herefrom or
therefrom shall be in writing and signed by Lessor.

         No right or  remedy  is  exclusive  of any  other  provided  herein  or
permitted by law or equity. All such rights and remedies shall be cumulative and
may be enforced concurrently or individually from time to time.

         23.  LESSOR'S  EXPENSE.  Lessee  shall pay  Lessor  on  demand  all its
reasonable  expenses  which  shall  not  exceed  the  amounts  set forth in each
Commitment  Letter without the written consent of Lessee  (including  reasonable
legal fees and expenses) incurred in connection with the preparation,  execution
and  delivery  of  this  Agreement  and  any  other  agreement  and  transaction
contemplated  hereby and all costs and  expenses  in  protecting  and  enforcing
Lessor's  rights  and  interests  in each  Lease and the  Equipment,  including,
without limitation, legal, collection and remarketing fees and expenses incurred
by Lessor in enforcing  the terms,  conditions  or  provisions of each Lease or,
upon the occurrence and continuation of an Event of Default.

         24. LESSEE'S WAIVERS. To the extent permitted by applicable law, Lessee
hereby  waives  any and all  rights  and  remedies  conferred  upon a lessee  by
Sections 2A-508 through 2A-522 of the UCC; provided,  however, that Lessee shall
have the right to recover  damages  from  Lessor for any breach by Lessor of its
obligations  under this  Agreement.  To the extent  permitted by applicable law,
Lessee also hereby  waives any rights now or  hereafter  conferred by statute or
otherwise which may require Lessor to sell, lease or otherwise use any Equipment
in  mitigation  of Lessor's  damages as set forth in Paragraph 22 above or which
may otherwise limit or modify any of Lessor's rights or remedies


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under Paragraph 22, except that Lessee shall have the right to require Lessor to
convey to Lessee, without representation,  warranty or recourse, all of Lessor's
rights,  title and  interest  in and to the  Equipment  upon  Lessor's  receipt,
following an event of default and the exercise of the Lessor's remedies,  of the
amounts  specified in Paragraph  22(f).  Any action by Lessee against Lessor for
any default by Lessor under any Lease shall be  commenced  within one year after
any such cause of action accrues.

         25. NOTICES;  ADMINISTRATION.  Except as otherwise provided herein, all
notices, approvals, consents, correspondence or other communications required or
desired to be given  hereunder  shall be given in writing and shall be delivered
by overnight  courier,  hand delivery or certified or registered  mail,  postage
prepaid,  if to Lessor,  then to Technology Finance Division,  76 Batterson Park
Road, Farmington,  Connecticut 06032, Attention: Assistant Vice President, Lease
Administration,  with a copy to Lessor at Riverway II, West Office  Tower,  9399
West Higgins Road, Rosemont,  Illinois 60018, Attention: Legal Department, if to
Lessee,  then to Sugen,  Inc.,  351 Galveston  Drive,  Redwood City,  California
94063-4720,  Attention: Vice President Finance or such other address as shall be
designated  by  Lessee  or  Lessor to the  other  party.  All such  notices  and
correspondence shall be effective when received.

         26. REPRESENTATIONS.  Lessee represents and warrants to Lessor that (a)
Lessee is duly organized,  validly  existing and in good standing under the laws
of the State of its incorporation;  (b) the execution,  delivery and performance
by  Lessee  of this  Agreement  are  within  Lessee's  powers,  have  been  duly
authorized  by all  necessary  action,  and do not and will not  contravene  (i)
Lessee's  organizational  documents or (ii) any law or  contractual  restriction
binding on or affecting Lessee; (c) no authorization or approval or other action
by, and no notice to or filing with,  any  governmental  authority or regulatory
body is required for the due  execution,  delivery and  performance by Lessee of
this  Agreement;  (d) each  Lease  constitutes  the  legal,  valid  and  binding
obligations of Lessee  enforceable  against Lessee in accordance  with its terms
except as may be limited by bankruptcy, reorganization, receivership, insolvency
or other laws affecting the enforcement of creditor's rights  generally;  (e) to
the  knowledge of Lessee the cost of each item of Equipment  does not exceed the
fair and usual price for such type of equipment  purchased in like  quantity and
reflects all discounts,  rebates,  and allowances for the Equipment  (including,
without limitation,  discounts for advertising, prompt payment, testing or other
services) given to the Lessee by the manufacturer, supplier or any other person;
and (f) all information  supplied by Lessee to Lessor in connection  herewith is
correct and does not omit any  material  statement  necessary to insure that the
information supplied is not misleading.

         27.  FURTHER  ASSURANCES.  Lessee,  upon the  request of  Lessor,  will
execute, acknowledge, record or file, as the case may be, such further documents
and do such further acts as may be reasonably necessary,  desirable or proper to
carry  out more  effectively  the  purposes  of this  Agreement.  Lessee  hereby
appoints Lessor as its limited  attorney-in-fact  to execute on behalf of Lessee
and  authorizes  Lessor to file without  Lessee's  signature  any UCC  financing
statements and amendments Lessor deems advisable.

         28. FINANCIAL  STATEMENTS.  Lessee shall deliver to Lessor: (a) as soon
as  available,  but not later than 120 days after the end of each fiscal year of
Lessee and its consolidated subsidiaries, the consolidated balance sheet, income
statement and  statements of cash flows and  shareholders  equity for Lessee and
its  consolidated  subsidiaries  (the  "Financial  Statements")  for such  year,
reported  on by  independent  certified  public  accountants  without an adverse
qualification;  and (b) as soon as  available,  but not later than 60 days after
the end of each of the first three fiscal  quarters in any fiscal year of Lessee
and its  consolidated  subsidiaries,  the Financial  Statements  for such fiscal
quarter,  as filed with the SEC.  Lessee shall also deliver to Lessor as soon as
available copies of all press releases

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<PAGE>


and other similar communications issued by Lessee and upon request of Lessor.

         29.  CONSENT  TO  JURISDICTION.   Lessee  irrevocably  submits  to  the
jurisdiction  of any Illinois state or federal court sitting in Illinois for any
action  or  proceeding  arising  out of or  relating  to this  Agreement  or the
transactions  contemplated hereby, and Lessee irrevocably agrees that all claims
in respect of any such action or proceeding  may be heard and determined in such
Illinois  state or federal  court.

         30. WAIVER OF JURY TRIAL. LESSEE AND LESSOR IRREVOCABLY WAIVE ALL RIGHT
TO TRIAL BY JURY IN ANY ACTION,  PROCEEDING  OR  COUNTERCLAIM  ARISING OUT OF OR
RELATING TO THIS AGREEMENT OR THE TRANSACTIONS  CONTEMPLATED HEREBY.

         31.  FINANCE  LEASE.  Lessee  and  Lessor  agree  that each  Lease is a
"Finance Lease" as defined by Section 2A-103(g) of the UCC. Lessee  acknowledges
that Lessee has reviewed and approved each written  Supply  Contract (as defined
by UCC 2A-103(y))  covering Equipment purchased from each "Supplier" (as defined
by UCC 2A-103(x))  thereof.

         32.  NO  AGENCY.  Lessee  acknowledges  and  agrees  that  neither  the
manufacturer or supplier, nor any salesman, representative or other agent of the
manufacturer or supplier, is an agent of Lessor. No salesman,  representative or
agent of the  manufacturer  or supplier is authorized to waive or alter any term
or condition of this Agreement or any Schedule and no  representation  as to the
Equipment or any other matter by the  manufacturer  or supplier shall in any way
affect Lessee's duty to pay Rent and perform its other  obligations as set forth
in this  Agreement or any  Schedule.

         33. SPECIAL TAX  INDEMNIFICATION.  Lessee  acknowledges that Lessor, in
determining the Rent due hereunder, has assumed that certain tax benefits as are
provided to an owner of property  under the Internal  Revenue  Code of 1986,  as
amended (the "Code"),  and under  applicable state tax law,  including,  without
limitation,  depreciation  deductions  under  Section  168(b) of the  Code,  and
deductions  under  Section  163 of the Code in an amount  at least  equal to the
amount of interest  paid or accrued by Lessor with  respect to any  indebtedness
incurred by Lessor in financing its purchase of the Equipment,  are available to
Lessor as a result of the lease of the Equipment.  In the event Lessor is unable
to obtain such tax benefits as a result of an act or omission of Lessee of which
Lessee has prior  written  notice and  opportunity  of comply,  is  required  to
include in income any amount  other than the Rent or is  required  to  recognize
income  in  respect  of the  Rent  earlier  than  anticipated  pursuant  to this
Agreement, Lessee shall pay Lessor additional rent ("Additional Rent") in a lump
sum in an amount  needed to provide  Lessor  with the same  after-tax  yield and
after-tax  cash flow as would have been  realized  by Lessor had Lessor (i) been
able to obtain such tax benefits, and (ii) not been required to recognize income
in respect of the Rent earlier than anticipated pursuant to this Agreement.  The
Additional Rent shall be computed by Lessor,  which computation shall be binding
on Lessee absent good faith contest by Lessee.  The Additional Rent shall be due
immediately  upon  written  notice by Lessor to Lessee of Lessor's  inability to
obtain tax  benefits,  the inclusion of any amount in income other than the Rent
or the  recognition  of income in respect of the Rent earlier  than  anticipated
pursuant to this  Agreement.  The  provisions of this Paragraph 33 shall survive
the termination of this Agreement.

         34.  GOVERNING LAW;  SEVERABILITY.  EACH LEASE SHALL BE GOVERNED BY THE
LAWS OF THE STATE OF  ILLINOIS  WITHOUT  GIVING  EFFECT TO THE  CONFLICT  OF LAW
PRINCIPLES   THEREOF.   IF  ANY  PROVISION  SHALL  BE  HELD  TO  BE  INVALID  OR
UNENFORCEABLE, THE VALIDITY AND ENFORCEABILITY OF THE REMAINING PROVISIONS SHALL
NOT IN ANY WAY BE AFFECTED OR IMPAIRED.

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LESSEE  ACKNOWLEDGES  THAT  LESSEE  HAS READ THIS  AGREEMENT  AND THE  SCHEDULES
HERETO,  UNDERSTANDS THEM, AND AGREES TO BE BOUND BY THEIR TERMS AND CONDITIONS.
FURTHER, LESSEE AND LESSOR AGREE THAT THIS AGREEMENT AND THE SCHEDULES DELIVERED
AND SIGNED BY LESSEE AND LESSOR IN CONNECTION HEREWITH FROM TIME TO TIME AND THE
COMMITMENT  LETTERS,  ARE THE COMPLETE AND EXCLUSIVE  STATEMENT OF THE AGREEMENT
BETWEEN THE PARTIES,  SUPERSEDING  ALL  PROPOSALS OR PRIOR  AGREEMENTS,  ORAL OR
WRITTEN,  AND ALL OTHER  COMMUNICATIONS  BETWEEN  THE  PARTIES  RELATING  TO THE
SUBJECT MATTER HEREOF.

                                       11

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         IN WITNESS  WHEREOF,  the parties  hereto have  executed or caused this
Agreement to be duly executed by their duly authorized  officers as of this 30th
day of November, 1997.


                                        SUGEN, INC.



                                        By: /s/ Stephen Evans-Freke
                                            ------------------------------
                                            Name: Stephen Evans-Freke
                                            Title: Chairman and Chief Executive
                                             Officer
                                            Federal Identification Number
                                             13-3629196


                                        TRANSAMERICA BUSINESS CREDIT CORPORATION



                                        By: /s/ Gary P. Moro
                                            ------------------------------
                                            Name: Gary P. Moro
                                            Title: Vice President


Form 1-11-11-97

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                                    EXHIBIT A


March 20, 1997


Ms. Christine Gray-Smith
Vice President Finance
Sugen, Inc.
515 Galveston Drive
Redwood City, California 94063-4720

Dear Christine:

Transamerica   Business  Credit   Corporation  -  Technology   Finance  Division
("Lessor") is pleased to offer to lease the Equipment  described below to Sugen,
Inc. ("Lessee"). This Commitment supersedes all prior correspondence, proposals,
and oral or other communications relating to leasing arrangements between Lessee
and Lessor. The outline of this offer is as follows:

Lessee:                             Sugen, Inc.

Lessor:                             Transamerica  Business Credit  Corporation -
                                    Technology   Finance   Division  and/or  its
                                    affiliates, successors and assigns.

Guarantors:                         None.

Equipment:                          A.     Laboratory,   Computer   and   Office
                                           Equipment  and  software  as  will be
                                           further   described   in  the   lease
                                           documentation.  All equipment subject
                                           to  approval   of  Lessor   prior  to
                                           funding  which  approval  will not be
                                           unreasonable withheld.

                                    B.     Tenant   Improvements   as   will  be
                                           further   described   in  the   lease
                                           documentation.

                                    C.     The Equipment and Tenant Improvements
                                           shall  include sale  leaseback  items
                                           purchased after December 1, 1996.

Equipment Cost:                     Not   to   exceed     $3,500,000     (Tenant
                                    Improvements  limited  to  $[...***...]  and
                                    Software limited to $[...***...]).

Equipment Location:                 Redwood City,  California or other locations
                                    acceptable to Lessor, which acceptance shall
                                    not be unreasonably withheld.

Anticipated Delivery:               December 1, 1996 through June 30, 1998.


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Termination of Commitment:          This  commitment will terminate if the first
                                    delivery of Equipment is not  completed  and
                                    funded on or before May 31, 1997.  The final
                                    delivery  of  Equipment  shall  not be later
                                    than June 30, 1998.

Lease Term
Commencement:                       Upon delivery  acceptance and funding of the
                                    Equipment   or  upon  each   completion   of
                                    deliveries   of  items  of  Equipment   with
                                    aggregate    cost   of   not    less    than
                                    $[...***...],  but in no  event,  shall  any
                                    Equipment be  delivered  later than June 30,
                                    1998.

Term:
(Equipment and Software)            From each Lease Term  Commencement  until 49
                                    months  from the first day of the month next
                                    following  or on the same  date as the Lease
                                    Term  Commencement if that date is the first
                                    date of the month.

Term:
(Tenant Improvements)               From each Lease Term  Commencement  until 37
                                    months  from the first day of the month next
                                    following  or on the same  date as the Lease
                                    Term  Commencement if that date is the first
                                    date of the month.

Lease Repayment Terms:
(Equipment and Software)            Monthly  Rent for  months 1 through 48 equal
                                    to  [...***...]  of  Equipment  Cost payable
                                    monthly in advance,  plus  applicable  sales
                                    and other  taxes.  Monthly Rent for month 49
                                    equal to [...***...] of Equipment  Cost. The
                                    first and 48th month's rent shall be payable
                                    in  advance.   Lessee  may  elect  Automatic
                                    Renewal  provision  of the  lease in lieu of
                                    making  the 49th  monthly  rent  payment  as
                                    described  above  upon  giving 60 days prior
                                    written notice to Lessor.  As of the date of
                                    each Lease Term  Commencement,  the  Monthly
                                    Rent Payments shall be fixed for the term.

Lease Repayment Terms:
(Tenant Improvements)               Monthly  Rent for  months 1 through 36 equal
                                    to [...***...] of Tenant  Improvements  Cost
                                    and  Equipment   Cost  payable   monthly  in
                                    advance,  plus  applicable  sales  and other
                                    taxes.  Monthly  Rent for  month 37 equal to
                                    [...***...] of Equipment Cost. The first and
                                    36th   month's  rent  shall  be  payable  in
                                    advance.  Lessee may elect Automatic Renewal
                                    provision of the lease in lieu of making the
                                    37th month's rent payment as described above
                                    upon giving 60 days prior written  notice to
                                    Lessor.  As of the date of each  Lease  Term
                                    Commencement,   the  Monthly  Rent  Payments
                                    shall be fixed for the term.

                                    The Lessor  reserves  the right to  increase
                                    the Monthly Rent  Payments as of the date of
                                    each Lease Term Commencement commensurate to
                                    the  [...***...]  of the  interest  rates of
                                    [...***...]  (in the case of Equipment)  and
                                    [...***...]   (in   the   case   of   Tenant
                                    Improvements  Cost)  from  the  week  ending
                                    March 5, 1997  ([...***...] and [...***...],
                                    respectively) to the week preceding the date
                                    of  each   Lease   Term   Commencement,   as
                                    published in


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                                    the Wall Street Journal.

Interim Rent Payments:              In   the   event   that   the   Lease   Term
                                    Commencement  is not on the first day of the
                                    month,  Interim Rent  Payments  shall accrue
                                    from each Lease Term Commencement  until the
                                    next  following  first  day of a  month  and
                                    shall be payable  at the end of that  month.
                                    Interim Rent Payments shall be calculated at
                                    the  daily   equivalent   of  the  currently
                                    adjusted Monthly Payment. Lessee will not be
                                    charged  Interim Rent on any  Schedule  that
                                    has a  Commencement  Date that  starts on or
                                    after the last 3 business days of a month.

Purchase Option:
(Equipment and Software)            Lessee shall have the option to purchase all
                                    (but not less than all) the Equipment or any
                                    schedule  at the  expiration  of the term of
                                    the Lease for $[...***...],  plus applicable
                                    sales and other taxes.

Automatic Renewal:
(Equipment and Software)            In the event  Lessee  does not elect to make
                                    the 49th  monthly  rent as  described in the
                                    Lease Repayment Terms above, the lease shall
                                    automatically  renew  for a term  of  twelve
                                    months.   The  Monthly   Rental  will  equal
                                    [...***...]  of the origiNal  Equipment Cost
                                    payable monthly in advance plus  [...***...]
                                    equal to  [...***...]  of the Equipment Cost
                                    after which time the Lessee may purchase the
                                    Equipment  for  $[...***...]  plus sales and
                                    other applicable taxes due at the end of the
                                    Renewal Term.

Purchase Option or
Automatic Renewal:
(Tenant Improvements)               Lessee shall have the option to purchase all
                                    (but  not  less  than  all)  of  the  Tenant
                                    Improvements  at the end of the  lease  term
                                    for  $[...***...]  plus applicable sales and
                                    other  taxes.   If  the  Lessee  renews  its
                                    existing Real Estate Lease for a period that
                                    exceeds the Tenant  Improvements Lease Term,
                                    then  Lessee  may  automatically  renew  the
                                    lease in lieu of  making  the  37th  monthly
                                    rent  payment  as  described  in  the  Lease
                                    Repayment  Terms  above,   the  lease  shall
                                    automatically  renew  for a term  of  twelve
                                    months   with   Monthly   Rental   equal  to
                                    [...***...]    of   the   original    Tenant
                                    Improvement   costs   payable   monthly   in
                                    advance,  after  which  time the  Lessee may
                                    purchase  all but not  less  than all of the
                                    Tenant  Improvements for  $[...***...]  plus
                                    sales and other  applicable taxes due at the
                                    end of the Renewal Term.

Documentation:                      The    documentation    relating   to   this
                                    transaction  shall implement the transaction
                                    contemplated  by this  commitment  letter to
                                    the  satisfaction of Lessor and its counsel,
                                    shall  be fully  acceptable  to  Lessor  and
                                    Lessee and their counsel,  and shall contain
                                    conditions    precedent,    representations,
                                    warranties and covenants by Lessee and shall
                                    provide for events of defaults and remedies,
                                    all as  reasonably  required  by Lessor  for
                                    transactions of this type. The documentation
                                    shall  include,  but not be limited  to, the
                                    terms  and  conditions   described  in  this
                                    commitment letter.


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Insurance:                          Prior  to any  delivery  of  Equipment,  the
                                    Lessee  shall  furnish  a   certificate   of
                                    insurance   acceptable   to  the  Lessor  in
                                    amount,   type,   and  term   covering   the
                                    Equipment   including  primary,   all  risk,
                                    physical damage,  property damage and bodily
                                    injury  with   appropriate  loss  payee  and
                                    additional insured  endorsements in favor of
                                    the Lessor.

Taxes:                              Sales  or use  taxes  would  be added to the
                                    Equipment  Cost or  collected  on the  gross
                                    rentals, as appropriate.

Representations and
Additional Covenants:               There  shall  be  no  actual  or  threatened
                                    conflict   with,   or   violation   of,  any
                                    regulatory   statute,   standard   or   rule
                                    relating to the Lessee its present or future
                                    operations, or the Collateral.

                                    All information supplied by the Lessee shall
                                    be materially correct and shall not omit any
                                    statement  necessary to make the information
                                    supplied not be  misleading.  There shall be
                                    no  material  breach of the  representations
                                    and  warranties  of the Lessee in the Lease.
                                    The  representations  shall include that the
                                    Equipment Cost of each item of the Equipment
                                    does not exceed the fair and usual price for
                                    such  type  of  Equipment  purchase  in like
                                    quantity purchased of such item and reflects
                                    all  discounts,  rebates and  allowances for
                                    the   Equipment   given  to  Lessee  by  the
                                    manufacturer,  supplier or any other  person
                                    including, without limitation, discounts for
                                    advertising,   prompt  payment,  testing  or
                                    other services.

Conditions Precedent to
Each Lease Term
Commencement:               1.      No material  adverse change in the financial
                                    condition, operation prospects of the Lessee
                                    prior to funding.  The Lessor  reserves  its
                                    right to rescind  any unused  portion of its
                                    commitment   in  the  event  of  a  material
                                    adverse  change in the financial or business
                                    standing of the Lessee.
                            2.      Completion  of the  documentation  and final
                                    terms of the proposed financing satisfactory
                                    to Lessor and Lessor's  counsel,  and Lessee
                                    and Lessee's counsel.
                            3.      Results  of  all  due  diligence,  including
                                    lien,  judgment  and tax  searches and other
                                    matters   Lessor   may   request   shall  be
                                    satisfactory to Lessor and Lessor's counsel.
                            4.      Receipt  by  Lessor of duly  executed  Lease
                                    documentation    in   form   and   substance
                                    satisfactory to Lessor and its counsel.
                            5.      Lessor shall  receive  title and a valid and
                                    perfected  first  priority lien and security
                                    interest  in the  Equipment  and  all  other
                                    Equipment  acquired  through the use of this
                                    Commitment  and Lessor  shall have  received
                                    satisfactory  evidence  that  there  are  no
                                    liens on any  Equipment  except as expressly
                                    permitted herein.

Tenant Improvements
Termination Provision:              If the Lessee  elects to vacate its  present
                                    operating  facility (which is defined as any
                                    facility    in   which    Lessor's    Tenant
                                    Improvements

                                       4

<PAGE>


                                    reside),then  the Lessor  will  release  its
                                    ownership  position  in all  of  its  Tenant
                                    Improvements.  In  return  the  Lessee  will
                                    provide  compensation  to the Lessor for the
                                    release of Tenant  Improvements  in the form
                                    of an increase to the monthly  rental factor
                                    on   the   remaining    rental   of   Tenant
                                    Improvements  which can not be  removed  and
                                    used by [...***...] (or from  [...***...] of
                                    Tenant   Improvements  Cost  monthly).   The
                                    release  will be subject to the Lessee being
                                    in  substantial  compliance  with all  other
                                    terms and conditions of the lease.

Fees and Expenses:                  The  Lessee  shall  be  responsible  for the
                                    Lessor's  reasonable  expenses not to exceed
                                    $[...***...]    without   Lessee's   written
                                    consent   (including   legal   expenses)  in
                                    connection with the transaction.

Law:                                This  letter  and  the  proposed  Lease  are
                                    intended to be governed by and  construed in
                                    accordance  with Illinois law without regard
                                    to its conflict of law provisions.

Indemnity:                          Lessee  agrees  to  indemnify  and  to  hold
                                    harmless Lessor, and its officers, directors
                                    and employees  against all claims,  damages,
                                    liabilities   and  expenses   which  may  be
                                    incurred  by or  asserted  against  any such
                                    person in connection  without arising out of
                                    this    letter    and    the    transactions
                                    contemplated   hereby,  other  than  claims,
                                    damages,  liability,  and expense  resulting
                                    from  such  person's  gross   negligence  or
                                    willful misconduct.

Confidentiality:                    This  letter  is  delivered  to you with the
                                    understanding   that   neither  it  nor  its
                                    substance  shall be  disclosed  publicly  or
                                    privately to any third  person  except those
                                    who are in a  confidential  relationship  to
                                    you  (such  as  your   legal   counsel   and
                                    accountants),  or where the same is required
                                    by law and then  only on the  basis  that it
                                    not be further  disclosed,  which conditions
                                    the Lessee and its agents  agree to be bound
                                    by upon acceptance of this letter.

                                    Without   limiting  the  generality  of  the
                                    foregoing, none of such persons shall use or
                                    refer to Lessor or to any affiliate  name in
                                    any disclosures  made in connection with any
                                    of the  transactions  without Lessor's prior
                                    written consent.

Conditions of Acceptance:           This  Commitment  Letter is intended to be a
                                    summary of the most  important  elements  of
                                    the   agreement  to  enter  into  a  leasing
                                    transaction  with Lessee,  and it is subject
                                    to all requirements and conditions contained
                                    in Lease documentation proposed by Lessor or
                                    its  counsel in the  course of  closing  the
                                    lease described herein.  Not every provision
                                    that imposes duties,  obligations,  burdens,
                                    or   limitations   on  Lessee  is  contained
                                    herein,  but shall be contained in the final
                                    Lease  documentation  satisfactory to Lessor
                                    and its counsel.

EACH OF THE PARTIES HERETO IRREVOCABLY AND  UNCONDITIONALLY  WAIVES ALL RIGHT TO
TRIAL BY JURY IN ANY SUIT, ACTION,  PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR
RELATED TO THIS LETTER OR THE TRANSACTION DESCRIBED IN THIS LETTER.


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Commitment Fee:                     A Commitment Fee equal to [...***...] of the
                                    total Equipment Cost and Tenant Improvements
                                    $([...***...])  shall be due the Lessor upon
                                    acceptance   of   this    Commitment.    The
                                    $[...***...] application Fee previously paid
                                    by Lessee to Lessor  shall be applied to the
                                    Commitment  Fee.  The  Commitment  Fee shall
                                    then be  applied  to the cost  and  expenses
                                    incurred    by   Lessor   (not   to   exceed
                                    $[...***...])   in   connection   with   the
                                    transaction,  and  the  remainder  shall  be
                                    applied to the second month's rent due under
                                    the Lease or  subsequent  months until fully
                                    utilized.   Upon   request   by  Lessee  the
                                    Commitment  Fee shall be  refunded to Lessee
                                    if the Lease  Agreement  is not  executed by
                                    March 31, 1997.

Commitment Expiration:              This  Commitment  shall  expire on March 25,
                                    1997,  unless prior thereto either  extended
                                    in  writing  by the  Lessor or  accepted  as
                                    provided below by the Lessee.

Should  you have any  questions,  please  call me.  If you wish to  accept  this
Commitment,  please so indicate by signing and returning the enclosed  duplicate
copy of this letter to me by March 25, 1997.


                                                    Yours truly,

                                                    TRANSAMERICA BUSINESS CREDIT
                                                    CORPORATION-TECHNOLOGY
                                                    FINANCE DIVISION




                                                    By /s/ Gerald A. Michaud
                                                       -------------------------
                                                       Gerald A. Michaud
                                                       Senior Vice President -
                                                       Marketing

Accepted this 25th day of  March, 1997

SUGEN, INC.


By: /s/ Christine Gray-Smith
   ---------------------------
    Typed or Printed Name

Title:  Vice President, Finance
   ---------------------------


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                                    EXHIBIT B

November 5, 1997

                                     Revised


Ms. Christine Gray-Smith
Vice President, Finance
Sugen, Inc.
515 Galveston Drive
Redwood City, CA 94063-4720

Dear Chris:

Transamerica   Business  Credit   Corporation  -  Technology   Finance  Division
("Lessor") is pleased to offer this commitment (this  "Commitment") to lease the
equipment described below to Sugen, Inc. ("Lessee").  Except with respect to the
transactions  consummated (or to be consummated) under a commitment letter dated
as of March 20, 1997 and the Master Lease  Agreement dated as of March 28, 1997,
this Commitment  supersedes all prior correspondence,  commitments,  and oral or
other communications relating to leasing arrangements between Lessor and Lessee.

The outline of this offer is as follows:

Lessee:                             Sugen, Inc.

Lessor:                             Transamerica  Business Credit  Corporation -
                                    Technology Finance Division

Equipment:                          A.     Laboratory,   computer   and   office
                                           equipment  and  software,   including
                                           without  limitation,  all  additions,
                                           improvements,  replacements, repairs,
                                           appurtenances,    substitutions   and
                                           attachments  thereto and all proceeds
                                           thereof.  All  Equipment  subject  to
                                           approval  of Lessor  prior to funding
                                           which    approval    will    not   be
                                           unreasonable withheld.

                                    B.     Tenant   Improvements   as   will  be
                                           further   described   in  the   lease
                                           documentation.

Equipment Cost:                     Not   to   exceed     $5,000,000     (Tenant
                                    Improvements limited to $[...***...] and and
                                    Software limited to $[...***...]).

Equipment Location:                 California (or other location  acceptable to
                                    Lessor).

Anticipated Delivery:               September 1, 1997 to December 31, 1998

Lease Term
Commencement:                       Upon delivery, acceptance and funding of the
                                    Equipment   or  upon  each   completion   of
                                    deliveries   of  items  of  Equipment   with
                                    aggregate    cost   of   not    less    than
                                    $[...***...], but no later than December 31,
                                    1998.


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Term:                               From each Lease Term  Commencement  until 49
                                    months  from the first day of the month next
                                    following or coincident with that Lease Term
                                    Commencement.

Monthly Rent
(Equipment and Software
  Only):                            Monthly   Rent  for  the   first  48  rental
                                    payments  will be  equal to  [...***...]  of
                                    Equipment  Cost   (Equipment  and  Software)
                                    payable  monthly  in  advance  and one final
                                    rental   payment  equal  to  [...***...]  of
                                    Equipment Cost (Equipment and Software) will
                                    be payable in advance at month 49. The first
                                    and  48th  months'  rent  will  be due on or
                                    before  each  Lease Term  Commencement.  The
                                    Lessee may at its option elect to accept the
                                    automatic    renewal   described   in   this
                                    Commitment in lieu of making the 49th rental
                                    payment as described above.

Monthly Rent
(Tenant Improvements
  Only):                            Monthly   Rent  for  the   first  48  rental
                                    payments  will be  equal to  [...***...]  of
                                    Equipment Cost (Tenant Improvements) payable
                                    monthly  in  advance  and one final  payment
                                    equal  to   [...***...]  of  Equipment  Cost
                                    (Tenant  Improvements)  will be  payable  in
                                    advance  at month  49.  The  first  and 48th
                                    months'  rent will be due on or before  each
                                    Lease Term  Commencement.  The Lessee may at
                                    its  option  elect to accept  the  automatic
                                    renewal described in this Commitment in lieu
                                    of  making  the  49th   rental   payment  as
                                    described above.

Adjustment to
Rental Payments:                    The Lessor  reserves  the right to  increase
                                    the Monthly Rent  Payments as of the date of
                                    each Lease Term Commencement  proportionally
                                    to  the  change  in the  [...***...]  of the
                                    interest  rates of  [...***...]  to the week
                                    preceding   the  date  of  each  Lease  Term
                                    Commencement,   as  published  in  the  Wall
                                    Street Journal. As of the date of each Lease
                                    Term Commencement, the Monthly Rent Payments
                                    will be fixed for the term.  A  schedule  of
                                    the actual  Monthly  Rent  Payments  will be
                                    provided by the Lessor  following each Lease
                                    Term Commencement.

Interim Rent:                       Interim  Rent will  accrue  from each  Lease
                                    Term  Commencement  until the next following
                                    first day of a month  (unless the Lease Term
                                    Commencement  is on or within three business
                                    days  prior to the  first  day of a  month).
                                    Interim Rent will be at the daily equivalent
                                    of  the  currently   adjusted  Monthly  Rent
                                    Payment.

Net Lease:                          The lease  will be a net lease  under  which
                                    the   Lessee   will   be   responsible   for
                                    maintenance, insurance, taxes, and all other
                                    costs and expenses.

Taxes:                              Sales  or use  taxes  shall  be added to the
                                    gross rentals, as appropriate.

Insurance:                          Prior  to any  delivery  of  Equipment,  the
                                    Lessee   will   furnish    confirmation   of
                                    insurance  acceptable to the Lessor covering
                                    the Equipment  including


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                                    primary, all risk, physical damage, property
                                    damage and bodily  injury  with  appropriate
                                    loss  payee  endorsement  in  favor  of  the
                                    Lessor.

Conditions Precedent to
Each Lease Term
Commencement:                       1.  No  material   adverse   change  in  the
                                    financial condition,  operation or prospects
                                    of the Lessee  prior to funding.  The Lessor
                                    reserves  the right to  rescind  any  unused
                                    portion of this Commitment in the event of a
                                    material  adverse  change  in the  financial
                                    condition,  operation  or  prospects  of the
                                    Lessee.
                                    2. Completion of the documentation and final
                                    terms of the proposed financing satisfactory
                                    to Lessor and Lessor's counsel.
                                    3. Results of all due  diligence,  including
                                    lien,  judgment  and tax  searches and other
                                    matters Lessor may reasonably  request shall
                                    be   satisfactory  to  Lessor  and  Lessor's
                                    counsel.
                                    4. Receipt by Lessor of duly executed  Lease
                                    documentation    in   form   and   substance
                                    satisfactory to Lessor and its counsel.
                                    5. Lessor  shall  receive  title and a valid
                                    and  perfected   first   priority  lien  and
                                    security interest in all Equipment  acquired
                                    through  the  use  of  this  Commitment  and
                                    Lessor  shall  have  received   satisfactory
                                    evidence  that  there  are no  liens  on any
                                    Equipment  except  as  expressly   permitted
                                    herein.

Purchase Option
(Equipment and Software
  Only):                            The Lessee  will have the option to purchase
                                    all (but not less than all) the Equipment at
                                    the expiration of the term of the Leases for
                                    $[...***...] plus applicable sales and other
                                    taxes.  In the  event  the  Lessee  does not
                                    elect to make the 49th  payment as described
                                    in the Monthly Rent (Equipment and Software)
                                    paragraph  of this  Commitment,  each  Lease
                                    will  automatically  renew for a term of one
                                    year   with   monthly   rentals   equal   to
                                    [...***...] of Equipment Cost (Equipment and
                                    Software)  payable  monthly in advance  plus
                                    one additional  payment equal to [...***...]
                                    of  the  Equipment   Cost   (Equipment   and
                                    Software).

Purchase Option
(Tenant Improvements
  Only):                            The Lessee  will have the option to purchase
                                    all (but not less  than  all) of the  Tenant
                                    Improvements  at the expiration of the term,
                                    or, if applicable,  the renewal term, of the
                                    Leases  for  $[...***...]   plus  applicable
                                    sales  and other  taxes.  If the term of the
                                    Lessee's  existing real estate lease exceeds
                                    the  the   term   of   Leases   for   Tenant
                                    Improvements  by at least one year, then the
                                    Lessee  may  elect  not  to  make  the  49th
                                    payment as  described  in the  Monthly  Rent
                                    (Tenant  Improvements)   paragraph  of  this
                                    Commitment,  in which  case  each  Lease for
                                    Tenant Improvements will automatically renew
                                    for a  period  of  12  months  with  monthly
                                    rentals  equal to  [...***...]  of Equipment
                                    Cost (Tenant Improvements).

Additional Covenants:               There  will  be  no  actual  or   threatened
                                    conflict   with,   or   violation   of,  any


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                                    regulatory   statute,   standard   or   rule
                                    relating  to  the  Lessee,  its  present  or
                                    future operations, or the Equipment.

                                    Lessee will  continue  to provide  copies of
                                    its  quarterly  filings  to  the  Securities
                                    Exchange    Commission.    All   information
                                    supplied  by the Lessee  will be  materially
                                    correct  and will  not  omit  any  statement
                                    necessary to make the  information  supplied
                                    not be misleading. There will be no material
                                    breach of the representations and warranties
                                    of   the   Lessee   in   the   lease.    The
                                    representations   will   include   that  the
                                    Equipment Cost of each item of the Equipment
                                    does not exceed the fair and usual price for
                                    like  quantity  purchased  of such  item and
                                    reflects   all   discounts,    rebates   and
                                    allowances for the Equipment given to Lessee
                                    or   any   affiliate   of   Lessee   by  the
                                    manufacturer,   supplier   or  anyone   else
                                    including, without limitation, discounts for
                                    advertising,   prompt  payment,  testing  or
                                    other services.

Fees and Expenses:                  The  Lessee  will  be  responsible  for  the
                                    Lessor's  reasonable  expenses in connection
                                    with the transaction. Lessor's expenses will
                                    be capped at $[...***...].

Law:                                This  letter  and  the  proposed  Lease  are
                                    intended to be governed by and  construed in
                                    accordance  with Illinois law without regard
                                    to its conflict of law provisions.

Indemnity:                          Lessee  agrees  to  indemnify  and  to  hold
                                    harmless Lessor, and its officers, directors
                                    and employees  against all claims,  damages,
                                    liabilities   and  expenses   which  may  be
                                    incurred  by or  asserted  against  any such
                                    person in connection  with or arising out of
                                    this    letter    and    the    transactions
                                    contemplated   hereby,  other  than  claims,
                                    damages,  liability,  and expense  resulting
                                    from  such  person's  gross   negligence  or
                                    willful misconduct.

Conditions of
Acceptance:                         This  Commitment  Letter is intended to be a
                                    summary of the most  important  elements  of
                                    the   agreement  to  enter  into  a  leasing
                                    transaction  with Lessee,  and it is subject
                                    to all requirements and conditions contained
                                    in Lease documentation proposed by Lessor or
                                    its  counsel in the  course of  closing  the
                                    Lease described herein.  Not every provision
                                    that imposes duties,  obligations,  burdens,
                                    or   limitations   on  Lessee  is  contained
                                    herein,  but shall be contained in the final
                                    Lease  documentation  satisfactory to Lessor
                                    and its counsel.

EACH OF THE PARTIES HERETO IRREVOCABLY AND  UNCONDITIONALLY  WAIVES ALL RIGHT TO
TRIAL BY JURY IN ANY SUIT, ACTION,  PROCEEDING OR COUNTERCLAIM ARISING OUT OF OR
RELATED TO THIS LETTER OR THE TRANSACTION DESCRIBED IN THIS LETTER.

Application Fee:                    The $[...***...]  Application Fee previously
                                    paid by the Lessee shall be first applied to
                                    the  costs  and  expenses  of the  Lessor in
                                    connection  with


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                                    the     transaction     (not    to    exceed
                                    $[...***...]),  and any  remainder  shall be
                                    applied to the second month's rent due under
                                    the Lease or  subsequent  months until fully
                                    utilized.

Commitment
Expiration:                         This Commitment shall expire on November 10,
                                    1997,  unless prior thereto either  extended
                                    in  writing  by the  Lessor or  accepted  as
                                    provided below by the Lessee.

Should  you have any  questions,  please  call me.  If you wish to  accept  this
Commitment,  please so indicate by signing and returning the enclosed  duplicate
copy of this letter to me by November 10, 1997.


                                                    Yours truly,

                                                    TRANSAMERICA BUSINESS CREDIT
                                                    CORPORATION-TECHNOLOGY
                                                    FINANCE DIVISION




                                                    By /s/ Gerald A. Michaud
                                                       -------------------------
                                                       Gerald A. Michaud
                                                       Senior Vice President -
                                                       Marketing

Accepted this 5th day of  March, 1997

SUGEN, INC.


By: /s/ Christine Gray-Smith
   ---------------------------


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