SUGEN INC
10-K405, 1998-03-31
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
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================================================================================
                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM 10-K
(Mark one)

 X   Annual Report  Pursuant to Section 13 or 15(d) of the  Securities  Exchange
- ---  Act of 1934 for the fiscal year ended December 31, 1997.

                                       OR

     Transition  Report  Pursuant  to  Section  13 or  15(d)  of the  Securities
- ---  Exchange Act of 1934.

                             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.)

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

                                 (650) 306-7700
              (Registrant's telephone number, including area code)

        Securities registered pursuant to Section 12(b) of the Act: None

           Securities registered pursuant to Section 12(g) of the Act:

                           Common Stock $.01 par value
                         Preferred Share Purchase Rights

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

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 by check mark if disclosure of delinquent  filers  pursuant to Item 405
of Regulation  S-K is not contained  herein,  and will not be contained,  to the
best of registrant's  knowledge,  in definitive proxy or information  statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K [X].

The aggregate  market value of the of the Common Stock of the registrant held by
non-affiliates as of March 13, 1998 was $141,903,757. (1)

The number shares of Common Stock  outstanding  at March 13, 1998 was 15,384,879
shares.

                       DOCUMENTS INCORPORATED BY REFERENCE
                        (To The Extent Indicated Herein)

Portions of Registrant's Definitive Proxy Statement which will be filed with the
Commission pursuant to Regulation 14A in connection with the 1998 Annual Meeting
are incorporated herein by reference in Part III of this Report.


- ---------------------------
(1)  Excludes  5,598,413  shares  of  the  Registrant's  Common  Stock  held  by
executive officers, directors and stockholders whose ownership exceeds 5% of the
Common Stock outstanding at March 13, 1998.
================================================================================

<PAGE>


                                     PART I

Item 1.           BUSINESS

         This Annual  Report on Form 10-K  contains  forward-looking  statements
within the meaning of Section 27A of the  Securities Act of 1933 and Section 21E
of the  Securities  Exchange Act of 1934 which are subject to the "safe  harbor"
created by those sections. These forward-looking statements include, but are not
limited to, statements  concerning the Company's plans to: continue  development
of its current  product  candidates;  conduct  clinical  trials with  respect to
SU101,  SU5416 and other  product  candidates;  utilize  the  Company's  capital
resources  and the time periods  related  thereto;  seek  regulatory  approvals;
engage  third-party  manufacturers  to supply its clinical trials and commercial
requirements;  establish a marketing,  sales and  distribution  capability;  and
evaluate  additional product  candidates for subsequent  clinical and commercial
development. These forward-looking statements may be found in the "Business" and
"Management's  Discussion  and  Analysis of Financial  Condition  and Results of
Operations"  sections  of  this  Annual  Report  on Form  10-K.  Forward-looking
statements not specifically set forth above may also be found in these and other
sections  of the Annual  Report on Form  10-K.  Each  statement  is based on the
current   expectations   of  the  Company  and  is  subject  to  the  risks  and
uncertainties inherent in the Company's business. In accordance with the Private
Securities Litigation Reform Act of 1995, the Company reminds investors that all
such  "forward-looking  statements"  are  necessarily  only  estimates of future
results  and  that  the  actual  results  achieved  by the  Company  may  differ
materially from these current expectations due to a number of factors, including
(i) the  Company's  technological  success  in  developing  lead  compounds  and
products;  (ii)  the  availability  and  terms  of  financing  of the  Company's
operations;  (iii) the actions of third  parties,  including  collaborators  and
competitors;  (iv) the demonstration of the safety and efficacy of the Company's
products at each stage of clinical development; (v) the ability to obtain patent
and other  proprietary  rights protection for the Company's  products;  (vi) the
receipt of timely  regulatory  approval  of the  Company's  products;  (vii) the
ability to manufacture product candidates in commercial quantities at reasonable
costs and in a manner acceptable to various regulatory  authorities;  and (viii)
market acceptance of the Company's  products.  Factors creating  uncertainty are
discussed in more detail in  individual  sections of this Annual  Report on Form
10-K.  In  particular,  see the  "Liquidity  and Capital  Resources"  section of
"Management's  Discussion  and  Analysis of Financial  Condition  and Results of
Operations."

Overview

         SUGEN is a  biopharmaceutical  company  focused  on the  discovery  and
development  of small  molecule  drugs which  target  specific  cellular  signal
transduction  pathways.  These signalling pathways are regulated by cell-surface
receptors  or  intracellular  signalling  molecules  known as  tyrosine  kinases
("TKs"),  tyrosine  phosphatases ("TPs") and serine-threonine  kinases ("STKs"),
three of the largest known  families of receptors in the body and key regulators
of critical  cellular  functions.  Aberrant  signalling of TKs, TPs and STKs has
been shown to result in a variety of chronic  and acute  pathological  diseases,
including cancer and diabetes as well as in dermatologic, ophthalmic, neurologic
and immune  disorders.  The Company  believes that compounds  designed to target
certain  kinases and  phosphatases  and inhibit  enzyme  activity or prevent the
binding of downstream  signalling molecules make attractive  therapeutic product
candidates.   The  Company's   research  and   development   efforts  in  signal
transduction are based upon the pioneering  accomplishments  of SUGEN's founding
scientists,  Dr. Axel Ullrich of  Max-Planck-Institut  fur Biochemie ("MPI") and
Dr. Joseph Schlessinger of New York University Medical Center ("NYU").

         SU101,   the  Company's   most  advanced   product   candidate,   is  a
platelet-derived  growth  factor  receptor  ("PDGF TK")  signalling  antagonist.
Imbalances in the PDGF TK signalling pathway have been shown by SUGEN and others
to be implicated in certain types of cancers.  The Company has completed a Phase
II  clinical  trial for use of SU101 as a  treatment  for  refractory  malignant
glioma and has recently  initiated a Phase III clinical  trial in first  relapse
glioma.  A Phase  II  clinical  trial of SU101 in  combination  with  BCNU,  the
chemotherapy  drug  that is part of the  standard  treatment  regimen  in  newly
diagnosed brain cancer patients,  was initiated in mid-1997, and the Company has
also recently initiated a Phase II clinical trial of SU101 in hormone refractory
prostate cancer. To date, over 158 patients have been treated with SU101 in nine
Company-sponsored  clinical  trials  including  patients  with  brain,  ovarian,
prostate and non-small cell lung cancers.

         The Company is also  conducting  its initial Phase I clinical trial for
its second cancer product  candidate,  SU5416,  a Flk-1/KDR TK antagonist  which
inhibits  angiogenesis (the process by which blood vessels are formed) and plans
to initiate Phase II clinical  trials in 1998. The  pharmaceutical  industry has
long sought tumor-specific inhibitors of angiogenesis with low toxicity profiles
because,  theoretically,  inhibiting angiogenesis may limit tumor growth, extend
the period of  disease-free  remission  in patients  who  respond to  front-line
therapy and reduce the potential for metastases. Potential oncology applications
for angiogenesis  include  treatments for most solid tumor types.  SUGEN is also
pursuing six additional  cancer-related  drug development  programs,  including:
Pan-Her, GRB2, Raf, PDGF TK (orally available), second generation

                                        2

<PAGE>
angiogenesis  inhibitors  and other  proprietary  programs,  many of which  lead
compounds are now undergoing in vivo pharmacology studies. The Company currently
plans to file two Investigational New Drug applications  ("IND") in each of 1998
and 1999,  but there can be no assurance that the Company will file such INDs at
such times or at all.

         SUGEN is also applying its drug discovery and  development  platform to
areas  outside  oncology,  including  dermatology,   ophthalmology,   rheumatoid
arthritis,  cardiovascular  disease,  diabetes,  neurodegenerative  diseases and
immunology.  The Company is conducting a Phase I clinical  trial for SU5271,  an
epidermal  growth factor  receptor ("EGF TK")  antagonist,  for the treatment of
psoriasis.

         SUGEN  employs  a   target-driven   approach  to  drug   discovery  and
development.  The Company  believes that the receptors and molecules that play a
causative  role in disease  states are  attractive  targets  for drug design and
development.   SUGEN's  drug   discovery   platform   consists  of:  (1)  target
identification, using advanced genomics techniques and the Company's proprietary
bioinformatics  program;  (2) target  validation  in  relevant  in vivo  disease
models;  (3) whole cell or other assay  design and  target-driven  screening  of
compounds  for  leads;  and (4)  lead  optimization  using  crystallography  and
computational  chemistry.  The  Company  believes  that its drug  discovery  and
development platform may reduce the cost, time and risk associated with bringing
potential  products to market by  rationally  screening  for potent and specific
drug  leads in the  early  stages  of  discovery  and  optimizing  pharmacologic
features in the later stages of drug development, thereby reducing the incidence
and severity of side effects.

         SUGEN  is   concurrently   pursuing   two   business   strategies   for
commercialization  of its products and technologies.  In the cancer field, SUGEN
intends to build a vertically  integrated  oncology  business in North  America,
with the  objective  of  bringing to market a family of  target-specific  signal
transduction   inhibitors   proprietary   to  SUGEN.   To  market  its  products
effectively, the Company currently intends to build a focused U.S. salesforce to
target the major cancer treatment centers.  The Company plans to seek additional
corporate partners to fund product development and commercialize its products in
Europe and Asia.  This strategy is  exemplified  by the Company's  collaboration
with ASTA Medica  Aktiengesellschaft  ("ASTA Medica") for the Pan-Her antagonist
program and the Raf  antagonist  program for the  treatment of certain  cancers.
ASTA Medica has been granted  marketing  rights to these  programs in Europe and
South  America.  While the  Company  generally  intends to retain  rights to its
cancer  programs  in North  America,  SUGEN is funding a portion of its  ongoing
cancer research through a collaboration  with Zeneca Limited  ("Zeneca") for the
development of five undisclosed  cancer targets.  Pursuant to its agreement with
Zeneca,  the Company will have the  opportunity  to obtain profit  participation
rights in the North  American  market by  contributing  to clinical  development
costs as incurred and will receive milestone payments and royalties on worldwide
sales.

         Outside  of  oncology,  the  Company's  strategy  is to seek  corporate
collaborations or joint ventures to which SUGEN contributes  validated  targets,
screening   technologies   and  drug  leads  while  the  partner   provides  the
disease-specific and drug development expertise as well as marketing experience,
in addition to providing funding to bring potential  products to market. As part
of  this  strategy,  the  Company  entered  into  a  collaboration  with  Vision
Pharmaceuticals,  L.P.,  an affiliate  of Allergan,  Inc.,  and  Allergan,  Inc.
(collectively,   "Allergan")   for   angiogenesis   inhibition   in   ophthalmic
applications.

Overview of Cellular Signal Transduction Pathways

         The last decade of research  has led to an increased  understanding  of
how cells  communicate  with each other to coordinate the growth and maintenance
of the  multitude  of  tissues  within  the human  body.  A key  element of this
communication  network is the  transmission  of a signal from the  exterior of a
cell to its nucleus,  which results in the activation or suppression of specific
genes.  This process is called signal  transduction.  An integral part of signal
transduction is the interaction of ligands,  receptors and intracellular  signal
transduction molecules ("downstream signalling molecules").

         Ligands  are  chemical  messengers,  usually  released  by one  cell to
communicate  with a target cell by binding to specific  receptors  on the target
cell's surface.  A receptor generally takes the form of a protein that straddles
a cell's membrane,  with its "ligand binding domain"  protruding out of the cell
and its "intracellular  domain" anchored inside the cell. When a ligand binds to
its receptor, the newly formed  receptor/ligand  complex triggers the activation
of a cascade  of  downstream  signalling  molecules,  thereby  transmitting  the
message  from the  exterior  of the cell to its  nucleus.  When the  message  is
received in the nucleus,  it dictates the  activation or suppression of specific
genes,  resulting  in the  production  of  proteins  that  carry out a  specific
biological response.  Depending on the specific ligand,  receptor and downstream
signalling  molecules,  the resulting  signalling  cascade  controls diverse and
distinct cellular processes. For example, metabolic changes can be effected by a
ligand such as insulin which, after binding to the insulin receptor, activates a
specific set of  downstream  signalling  molecules  within the cell,  ultimately
leading  to the  regulation  of  glucose  uptake  and  other  insulin-associated
functions.
                                        3
<PAGE>

Tyrosine Kinases,  Tyrosine Phosphatases and Serine-Threonine  Kinases in Signal
Transduction

         Kinases and phosphatases  are classes of signalling  molecules that are
central to the healthy functioning of all tissues.  The Company's research focus
in this area has been on TKs,  TPs and  selected  STKs.  At  present,  there are
approximately  100 known human TKs,  including Her2,  PDGF TK, insulin  receptor
("insulin TK"), EGF TK, macrophage colony  stimulating factor receptor and nerve
growth factor  receptor,  all of which have been cloned over the last  seventeen
years.   TPs  were  not  discovered   until  1988,  and  at  present  there  are
approximately 50 known human TPs.

         Generally,  when a ligand  binds to receptor  TKs, the  receptors  must
dimerize (join in pairs at the cell surface) to become activated.  This coupling
activates a specific  enzyme  activity  which resides  within the  intracellular
domain of each TK. Upon activation,  the TKs commence  cross-phosphorylation,  a
process whereby phosphates (highly charged particles) are enzymatically added to
specific sites on each of the TKs. These phosphates serve as attachment sites at
which specific  downstream  signalling  molecules interact with the TKs. Many of
these downstream signalling molecules in turn become phosphorylated  themselves,
enabling  them to  recruit  their own  substrates  and thus pass on the  signal.
Depending on the specific ligand and receptor,  the resulting signalling cascade
leads to changes in gene  expression  or affects  other  cellular  systems  that
ultimately  determine if the cell is to grow,  mature,  migrate,  metabolize  or
survive.

         Complementing TKs are TPs, which were first  characterized in detail by
Dr. Edmond H. Fisher,  a 1992 Nobel Laureate,  SUGEN  collaborator and member of
SUGEN's Science Advisory Board.  While the TKs phosphorylate  target proteins to
exert their activity, the TPs remove phosphates  ("dephosphorylate") from target
proteins, thereby regulating the activity of the TKs. Generally, when a receptor
TK is  activated  by  its  ligand,  a  given  biologic  response  is  triggered.
Conversely,  when a TP is activated, there is usually down regulation of a given
biologic response.  In this manner, TKs can be visualized as the "gas pedal" and
TPs as the "brake  pedal"  for  numerous  biological  processes.  Many  cellular
responses are thus regulated by the balance between specific TKs and TPs.

         The  most  abundant  kinases  in  the  cell  are  STKs,  enzymes  which
phosphorylate  serine and threonine  residues.  STKs are involved in controlling
the  cell  cycle,  the  response  of  the  cell  to  environmental  stress,  the
development  of  certain  cells  and  tissues,   and  other  processes  such  as
metabolism.  Many STKs,  for example,  Raf  kinases,  act  downstream  in signal
transduction   cascades   initiated  by  TKs,  while  others  integrate  signals
originating  from  other  classes  of  receptors,   such  as  G  protein-coupled
receptors.

Diseases and Disorders Related to TK, TP and STK Signalling Pathways

         TKs,  TPs,  STKs and  their  signalling  pathways  play key  roles in a
variety of normal cellular functions  involving virtually every cell type in the
body.  Examples  include the growth of epithelial cells (skin and lining tissues
of internal organs),  angiogenesis,  hematopoiesis,  proliferation of connective
tissue  cells  (fibroblasts),  survival  and  differentiation  of  nerve  cells,
regeneration  of tissues  during  wound  healing  and  regulation  of the energy
metabolism  of all cells.  While  normal  cellular  function  involves a balance
between kinase and phosphatase activity, imbalances between these molecules have
been shown to result in a variety of chronic and acute pathological  conditions,
including cancer and diabetes as well as in dermatologic, ophthalmic, neurologic
and immunologic disorders.

         The  close  association  of TKs,  TPs and STKs with  disease  make them
attractive  targets  for  drug  discovery  and  therapeutic  intervention.   The
intracellular domains where enzymatic activity occurs can be targeted with great
selectivity by drugs that inhibit enzyme activity or that prevent the binding of
downstream signalling molecules to the phosphorylated receptor.  Critical points
further  downstream in the  signalling  cascade may also be viable targets since
selective intervention at these points can prevent the message from reaching its
final destination in the nucleus.

Product Development Programs

         TKs, TPs, STKs and their biological  signalling pathways are implicated
in a broad number of diseases.  SUGEN focuses its product development efforts on
those areas which represent  significant market  opportunities and for which the
disease processes and signalling  pathways are well understood.  The Company has
several novel product  candidates in various stages of  development  for disease
areas in which  there is a critical  need for major  advances  in  efficacy  and
safety over currently available therapies. These diseases include cancer as well
as diabetes, psoriasis and cardiovascular, immunologic and neurologic disorders.
The  Company  has  completed  a Phase II  clinical  trial  for use of SU101 as a
treatment for refractory malignant glioma and has recently initiated a Phase III
clinical  trial in first relapse  glioma.  A Phase II clinical trial of SU101 in
combination  with  BCNU,  the  chemotherapy  drug  that is part of the  standard
treatment regimen in newly diagnosed brain cancer patients,

                                        4

<PAGE>


was initiated in mid-1997,  and the Company has also recently  initiated a Phase
II clinical trial of SU101 in hormone refractory prostate cancer. The Company is
also conducting its initial Phase I clinical trial for its second cancer product
candidate,  SU5416, a Flk-1/KDR TK antagonist which inhibits  angiogenesis.  The
Company currently plans to initiate a Phase II clinical trial of SU5416 in 1998,
although there can be no assurance as to the timing of the Phase II trial.

                                        5

<PAGE>


<TABLE>
         The following table outlines SUGEN's  development and research programs
which are being pursued either  independently by SUGEN or in collaboration  with
the Company's partners:

<CAPTION>
- ---------------------------------------------------------------------------------------------------------------
     Program                       Indication(s)                      Status(1)          Rights
- ---------------------------------------------------------------------------------------------------------------
                                                    Cancer
- ---------------------------------------------------------------------------------------------------------------
<S>                          <C>                                      <C>                <C>
SU101                        First Relapse malignant glioma           Phase III          SUGEN
PDGF TK Antagonist            - Monotherapy
                             Newly diagnosed malignant glioma         Phase II           SUGEN
                              - Combination therapy
                             Prostate cancer                          Phase II           SUGEN
                             Ovarian and non-small cell lung          Phase II           SUGEN
                             cancers
- ---------------------------------------------------------------------------------------------------------------
SU5416                       Angiogenesis inhibition                  Phase I            SUGEN
Flk-1/KDR TK Antagonist       -Most solid tumor types
- ---------------------------------------------------------------------------------------------------------------
Second Generation            Most solid tumor types                   Lead compounds     SUGEN
Angiogenesis Inhibitors
- ---------------------------------------------------------------------------------------------------------------
Raf Antagonist               Pancreatic, bladder cancers              Lead compounds     ASTA Medica
                                                                                            Europe and South
                                                                                            America
                                                                                         SUGEN
                                                                                            United States and
                                                                                            rest of world
- ---------------------------------------------------------------------------------------------------------------
Orally available PDGF TK     Malignant glioma, prostate, ovarian      Lead compounds     SUGEN
   Antagonists               and non-small cell lung cancers
- ---------------------------------------------------------------------------------------------------------------
Pan-Her Antagonist           Breast, ovarian, gastric, lung,          Preclinical        ASTA Medica
   (formerly Her2            head and neck, prostate cancers                                Europe and South
   Antagonist)                                                                              America
                                                                                         SUGEN
                                                                                            United States and
                                                                                            rest of world
- ---------------------------------------------------------------------------------------------------------------
GRB2 Antagonist              Multiple TK-driven tumors                Lead compounds     SUGEN
- ---------------------------------------------------------------------------------------------------------------
Met TK Antagonist            Stomach, colorectal and lung cancers     Screening          SUGEN
- ---------------------------------------------------------------------------------------------------------------
Five undisclosed cancer      Certain major cancers                    Research and       Zeneca
   targets                                                            screening
- ---------------------------------------------------------------------------------------------------------------
Other proprietary programs   Various cancers                          Research and       SUGEN
                                                                      screening
- ---------------------------------------------------------------------------------------------------------------
                                                Other Programs
- ---------------------------------------------------------------------------------------------------------------
SU5271                       Psoriasis                                Phase I            SUGEN
EGF TK Antagonist
- ---------------------------------------------------------------------------------------------------------------
Insulin TP Antagonist        Diabetes Type I/Type II                  Preclinical        SUGEN
- ---------------------------------------------------------------------------------------------------------------
Immunology targets           Immune suppression, acute                Research and       SUGEN
                             inflammation                             screening
- ---------------------------------------------------------------------------------------------------------------
Flk-1/KDR TK Antagonist      Rheumatoid arthritis                     Preclinical        SUGEN
(other targets)
- ---------------------------------------------------------------------------------------------------------------
Flk-1/KDR TK Antagonist      Angiogenesis inhibition in               Preclinical        Allergan
(other targets)              ophthalmology
                              - Diabetic retinopathy
                              - Macular degeneration
- ---------------------------------------------------------------------------------------------------------------
Neurology targets            Neurodegenerative diseases               Research and       SUGEN
                                                                      screening
- ---------------------------------------------------------------------------------------------------------------
PDGF TK Antagonist           Cardiovascular diseases                  Lead compounds     SUGEN
(and other targets)
- ---------------------------------------------------------------------------------------------------------------
</TABLE>

     "Research"            Cloning and  characterization of novel TKs, TPs, STKs
                           and related downstream  signalling  molecules (Target
                           Identification)  and  validation of the role, if any,
                           of  those   molecules  in  a  given  disease  (Target
                           Validation).

     "Screening"           Screening to identify lead compounds.

     "Lead Compounds"      Evaluating drug leads and/or natural product extracts
                           in  relevant  in  vitro  cellular  models   including
                           genetically engineered cell lines, as well as ex vivo
                           human tissues and in vivo animal models.

     "Preclinical"         Pharmacology  and  toxicology  testing in preclinical
                           models,  drug formulation and manufacturing  scale-up
                           to gather  necessary  data to comply with  applicable
                           regulatory  protocols  prior to  submission of an IND
                           with the FDA.

                                        6

<PAGE>


Cancer

         Research over the past 20 years has  reinforced the view that cancer is
a disease involving damage,  loss or amplification of specific genes.  Moreover,
of the  numerous  oncogenes  identified  to date,  many  appear  to be  abnormal
versions of TK and STK signalling pathway  components,  such as ligands,  TKs or
STKs or  downstream  signalling  molecules.  These  discoveries  have led to the
realization that  dysfunctional  TK or STK signalling  pathways play an integral
role in cancer.  More  recently,  TPs have been  implicated  as potential  tumor
suppressor genes due to their ability to counteract the activity of TKs.

         As a result of the close linkage between TK, TP and STK aberrations and
cancer,  SUGEN believes that certain cancers can be  recategorized  according to
specific  TK,  TP and STK  signalling  pathway  defects  rather  than  merely by
physical location in the body (e.g., breast, lung, brain).  Several observations
support  this  approach.  For  example,  TK  overexpression  is not a  transient
phenomenon.  Cancer cells that exhibit TK overexpression do so continuously.  In
addition,  in many cases a cancer cell exhibits heavy overexpression of only one
TK. For instance,  when cancer cells metastasize from a Her2-dependent tumor and
establish  themselves  at a remote site in the body,  the distal  tumor has also
been observed to  overexpress  Her2.  Furthermore,  SUGEN has shown that certain
tumor cells that  overexpress  a TK are more  sensitive  to TK  inhibitors  than
normal cells. The Company  believes that these  observations are the basis for a
new  approach to cancer  therapy  which might  commence  with a sample of biopsy
material being sent to a pathology lab for gene expression profiling in order to
determine the nature of the cellular  abnormality,  such as  overexpression of a
TK. This diagnosis could then be used to select the appropriate  target-specific
signal transduction inhibitor for treatment.

         Many of the cancers that SUGEN's  programs are addressing  have patient
subsets  with  extremely  poor  prognoses  and  no  alternative   for  effective
treatment.  For  example,  in certain  cancers of the brain,  breast,  ovary and
pancreas,  patient  subsets  can be  defined in  advance  for which the  average
survival time is short.  By focusing on these  patients  initially,  the Company
believes that it may be able to demonstrate  statistically  significant efficacy
with  relatively  small patient  numbers and possibly  shortened  clinical trial
duration  if the  compounds  prove  to be  active.  There  can be no  assurance,
however, that the Company will be able to rely on smaller-scale  clinical trials
to expedite commercialization of its products.

SU101/PDGF TK Antagonist. SU101 is a small synthetic molecule which inhibits the
platelet-derived  growth factor receptor  signalling  pathway.  PDGF is a growth
factor  ligand  that  stimulates  the growth of a variety of cell types  through
binding to the PDGF TK. The PDGF TK was first cloned by a group of collaborators
led by Dr.  Ullrich in 1983. In December  1994,  the Company filed its first IND
with the FDA for  SU101,  a PDGF TK  signalling  antagonist.  To date,  over 158
patients have been treated with SU101 in nine Company-sponsored clinical trials.
The  Company  has  completed  a Phase II  clinical  trial  for use of SU101 as a
treatment for refractory malignant glioma and has recently initiated a Phase III
clinical  trial in first relapse  glioma.  A Phase II clinical trial of SU101 in
combination  with  BCNU,  the  chemotherapy  drug  that is part of the  standard
treatment  regimen in newly  diagnosed brain cancer  patients,  was initiated in
mid-1997,  and the Company has also recently initiated a Phase II clinical trial
of SU101 in hormone  refractory  prostate cancer.  Based on Phase I and II data,
the Company may conduct  additional  Phase II clinical  trials in astrocytoma (a
type of primary brain cancer), ovarian and non-small cell lung cancers.

         To expedite the commercialization of SU101, the Company is focusing its
initial  development  efforts on malignant  glioma,  a highly  aggressive  brain
tumor,  and  selected  other  solid  tumor  patient  populations  with very poor
prognoses.  A subset of each of these  cancers  appears  to be  correlated  with
aberrant PDGF TK signalling.  Malignant  glioma patients and refractory  ovarian
patients have a mean survival time of approximately nine months and less than 12
months,  respectively.  Given the poor prognoses for these patients, the Company
believes that FDA approval could  potentially be obtained based on smaller-scale
clinical   trials  than  are  typically   required  for  approval  of  New  Drug
Applications "NDAs". There can be no assurance,  however,  that the Company will
be  able  to  rely  on   smaller-scale   clinical   trials   to   expedite   the
commercialization of SU101 for these patient  populations.  SUGEN believes SU101
may also have  applications  in other  cancers  that  involve  aberrant  PDGF TK
signalling,  including  prostate,  ovarian and  non-small  cell lung cancers and
currently  plans to proceed  with  multiple  registrational  studies in 1998 and
1999.  However,  no  assurance  can be given as to the ability of the Company to
proceed with such studies on a timely basis, or at all.

         In  December  1997 the Company was awarded two method of use patents in
the United States with respect to treating PDGF TK driven cancers with SU101. In
March 1997, the U.S.  patent office issued to SUGEN a patent on the  formulation
of SU101. The Company presently does not know if commercialization of SU101 will
infringe certain patents issued to a large  pharmaceutical  company but believes
that these  patents  may be subject to claims of  invalidity  as they  relate to
SU101. See "Patents and Proprietary Technology."

                                        7

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SU5416/Flk-1/KDR  TK  Antagonist.  Formation  of the  body's  network  of  blood
vessels, or angiogenesis,  occurs throughout  childhood.  This process generally
stops once a person reaches adulthood. Exceptions exist during wound healing and
the menstrual  cycle.  Angiogenesis is re-triggered in adults,  however,  during
certain pathological conditions including tumor formation and metastasis, and in
certain  ophthalmic  disorders,   including  diabetic  retinopathy  and  macular
degeneration.  The  pharmaceutical  industry  has  long  sought  small  molecule
inhibitors of angiogenesis with low toxicity  profiles  because,  theoretically,
inhibiting   angiogenesis   may  limit  tumor  growth,   extend  the  period  of
disease-free  remission in patients who respond to front-line therapy and reduce
the potential for metastases.  The potential  markets for such a product include
all patients with solid tumors where angiogenesis  inhibition may play a role as
an important adjunctive therapy, and in patients with metastatic disease.

         SUGEN and its  collaborators  have  identified  the  Flk-1/KDR  TK as a
receptor  for  vascular  endothelial  growth  factor  ("VEGF")  and  as a  major
regulator of angiogenesis.  Blocking Flk-1/KDR TK activity blocks the ability of
most tumors to stimulate  formation of blood vessels and thus deprives the tumor
of necessary nutrients. In preclinical studies conducted by researchers at SUGEN
and  collaborating  laboratories,  small  molecule  inhibitors  of the Flk-1/KDR
blocked   VEGF-dependent   angiogenesis,   as  well  as  vascular  permeability.
Additionally,  human  endothelial  cells were  prevented  from  undergoing  cell
division that is required for the formation of new blood vessels.  In June 1997,
the  Company  filed an IND in  cancer  for  SU5416,  a drug  developed  from the
Company's  Flk-1/KDR TK angiogenesis  inhibitor program that addresses  patients
with solid tumors and may also have  application  as an  anti-metastasis  agent.
Phase I  clinical  trials in  patients  with  solid  tumors  were  initiated  in
September 1997 and Phase II clinical trials are currently planned to commence in
1998, pending Phase I results.

         The  Company  has  established  an  exclusive  research  and  licensing
agreement  with  the   Max-Planck-Institut   fur  Physiologische  and  Klinische
Forschung  ("MPP")  (MPI  and  MPP  are  collectively   referred  to  herein  as
"Max-Planck  Society" or "MPS") to support the work of Dr. Werner Risau, a SUGEN
consultant  and a director of MPP, and his  laboratory.  Dr. Risau is one of the
leading  researchers in the field of  angiogenesis.  In  collaboration  with the
laboratories of Dr. Risau and Dr. Ullrich,  SUGEN is conducting  further studies
into the mechanisms of angiogenesis,  including the identification of additional
TK and TP related  signalling  pathways involved in angiogenesis.  See "Research
Collaborations."

Second  Generation  Angiogenesis  Inhibitors.   Through  the  Company's  ongoing
research  and drug  discovery  efforts  in  angiogenesis,  SUGEN has  identified
additional  potential drug candidates  which have  demonstrated  good potency on
Flk-1/KDR,  and additional  targets  including PDGF-R and FGF-R which may play a
role in the angiogenic process and tumor metastasis.  With the possibility of an
increased  spectrum  of  activity  from  this  expanded  target  profile,  SUGEN
currently  plans to advance the most  promising  of these drug  candidates  into
Phase I clinical trials in 1998 and may determine to seek to  commercialize  one
or more angiogenesis  inhibitors based on future clinical results. No assurance,
however, can be given as to the ability of the Company to commence such clinical
trials on a timely basis, or at all.

GRB2 Antagonist. Growth factor receptor binding protein 2 ("GRB2"), a downstream
signalling  adaptor  molecule,  was  originally  cloned  by  Dr.  Schlessinger's
laboratory.  GRB2  has been  shown  to be an  essential  element  in the  signal
transduction  pathway of many TKs,  particularly  as a link between TKs and Ras.
(See "Raf Antagonist" below). SUGEN is investigating the role of GRB2 in linking
TK signalling to Ras activation in certain TK induced  cancers,  with the belief
that  inhibition  of GRB2 might be of  therapeutic  benefit for a broad range of
cancers typified by an activation of the TK-Ras pathway. In April 1997, the U.S.
patent office issued a patent on SUGEN's  proprietary  cancer target GRB2. Other
patent claims with respect to this target have also been filed.

         SUGEN has developed  proprietary assays for  high-throughput  screening
for GRB2 inhibitors and has now identified a novel class of signal  transduction
inhibitors  that act by blocking the function of the GRB2  adaptor  protein.  In
vitro studies  indicate that SUGEN's GRB2  inhibitors act as cytostatic  agents,
causing  cancerous  cells to cease  multiplying or enter  programmed  cell death
(apoptosis).  Preliminary  in vivo  studies  indicate  efficacy in tumor  growth
inhibition with identified lead compounds.

Pan-Her Antagonist (formerly Her2 Antagonist). Her2 is a TK, first cloned by Dr.
Ullrich,  which is  believed  to play an  important  role in certain  aggressive
breast, ovarian,  gastric and lung cancers. Dr. Ullrich and Dr. Dennis Slamon of
the University of California at Los Angeles Medical Center and member of SUGEN's
Science Advisory Board have established the clinical relevance of overexpression
of Her2 in human breast and ovarian cancers. In their study of approximately 200
patients,  it was found that  almost 30% of breast and ovarian  cancer  patients
overexpress  Her2 and that high levels of Her2 in a patient's  tumor  correlated
with reduced  survival  time.  Since that time,  subsets of other types of human
tumors  have been shown to express  high levels of Her2,  including  gastric and
lung cancers.  Animal data from several  laboratories has demonstrated  that the
suppression  of Her2  activity  has a  significant  inhibitory  effect  on tumor
growth, validating Her2 as a target for cancer

                                        8

<PAGE>


therapy in the subset of patients that overexpress this TK.

         Monoclonal  antibodies  targeting Her2,  including one developed by Dr.
Ullrich,  are currently in clinical trials by others for certain cancers.  While
the Company  believes  that these  trials may serve to  validate  the concept of
targeting aberrant TKs in cancer, SUGEN believes that a small molecule inhibitor
of Her2 which also blocks the closely  related Her1 and Her4 receptors  (thus, a
Pan-Her antagonist) has the potential to be a more attractive therapy. SUGEN has
identified a number of  potentially  highly potent and specific  small  molecule
inhibitors  of  Pan-Her.  The  Company  is  currently  testing  several of these
molecules in animal models.  SUGEN is pursuing its Pan-Her antagonist program in
collaboration  with ASTA Medica,  and in January 1998 the two companies  jointly
announced  they  would  be the  advancing  the  Pan-Her  program  into  clinical
development with Phase I clinical trials  currently  scheduled to commence later
this  year.  However,  no  assurance  can be  given  to the  ability  of the two
companies to enter such clinical trials on a timely basis, or at all.

Orally Available PDGF TK Antagonist.  SUGEN is committed to developing an orally
active  small  molecule  inhibitor  of the PDGF TK  signalling  pathway.  From a
commercialization  standpoint, an orally active compound may be complementary to
SU101 in that it may be  developed  for use as a chronic  therapy.  The  Company
currently  has  several  small  molecule  inhibitors  of the PDGF TK  signalling
pathway which in vivo animal studies appear to be orally  available and may have
the  potential  to  treat  numerous  PDGF  TK-driven  proliferative   disorders,
especially  cancers.  The PDGF TK also appears to be involved in both restenosis
of  blood  vessels  after  clearance  by   angioplasty,   and  more  broadly  in
atherosclerosis.

Raf Antagonist.  Raf, an STK, is a downstream  signalling molecule through which
numerous  signalling  pathways  have  been  found to  converge.  Raf is known to
interact  with the  oncogene  Ras, and is required in order for Ras to relay its
signals.  The Ras  oncogene  has long  been  known to play an  integral  role in
certain  cancers,  and may be  involved  in  over  20% of all  tumors  including
approximately 90% of pancreatic tumors. Moreover, Ras has drawn the attention of
the  pharmaceutical  industry for many years because of its frequent  mutational
activation in tumor cells. However,  since its biochemical activity and upstream
activators  were not well  defined,  the  search for Ras  inhibitors  has proved
difficult.  In contrast, the Company believes that Raf is a more suitable target
for therapeutic intervention.

         Dr.  Ulf Rapp,  Director  of  Molecular  Biology at the  University  of
Wurzburg,   Germany,   a  SUGEN  consultant  and  the  discoverer  of  Raf,  has
demonstrated that inhibition of Raf blocks the  tumor-forming  potential of Ras.
SUGEN has  developed  proprietary  Raf-based  assays and is screening  for small
molecule  inhibitors  of Raf. The Company  believes  that drugs that inhibit Raf
signalling  may arrest tumors  driven by excessive Ras activity.  The Company is
pursuing its Raf Antagonist program in collaboration with ASTA Medica.

Met TK Antagonist.  Overexpression  of Met TK may be implicated in a significant
portion of tumors of the lung,  stomach and colon.  Moreover,  Met TK may play a
role in the  metastasis of solid  tumors.  SUGEN has recently  completed  target
validation studies on Met TK and has commenced screening against this target.

Psoriasis

         Psoriasis is a chronic skin  disorder that affects  approximately  four
million people in the United States,  and annual treatment costs in this country
are estimated at over $1.5 billion.  There are few currently available drugs for
this disease that offer satisfactory efficacy and safety.  Hyperproliferation of
keratinocytes  contributes  to  psoriasis,  and research by SUGEN and others has
demonstrated that EGF TK signalling is required for the growth of keratinocytes.
SUGEN's  research in psoriasis  was  conducted in part by Hebrew  University  of
Jerusalem.

SU5271/EGF  TK  Antagonist.  SU5271,  a  selective  inhibitor  of  EGF  receptor
signalling,  represents the first  extension of SUGEN's drug discovery  platform
into the  field of  dermatology.  SUGEN has  received  an  exclusive,  worldwide
license  from  Zeneca  for the  dermatologic  uses of SU5271  and has also filed
patent applications of its own with respect to this compound.

         The Company is currently conducting Phase I clinical trials to evaluate
the safety of the  topical  use of SU5271 in  psoriatic  patients at Mount Sinai
Hospital in New York.  SU5271 is a synthetic small molecule signal  transduction
inhibitor that blocks keratinocyte growth.

Angiogenesis Inhibition in Ophthalmology

         A number of ophthalmological  disorders involve  neovascularization  of
different  regions of the eye.  Since  Flk-1/KDR  TK is known to be important in
other  neovascularization  processes  (such as in  tumors),  it may also  play a
crucial role in ocular  neovascularization.  Thus, Flk-1/KDR TK inhibitors might
be therapeutically

                                        9

<PAGE>


beneficial  for treating  ophthalmic  disorders.  In October  1996,  the Company
signed  a  collaboration  agreement  with  Allergan  to  identify,  develop  and
commercialize  novel  angiogenesis  inhibitors  for the  treatment of ophthalmic
diseases.  Flk-1/KDR  TK and other  angiogenesis  targets  are  currently  under
evaluation.

Diabetes

         Both Type I and Type II diabetes are  characterized  by  pathologically
high levels of blood glucose due to inefficient  cellular  uptake and metabolism
of glucose.  Type I diabetes is characterized by insufficient  levels of insulin
and is  thought to be caused by the  autoimmune  destruction  of the  pancreatic
cells that make insulin.  In contrast,  Type II diabetics often produce elevated
levels  of  insulin,  although  this  insulin  does not seem to have  sufficient
effect.  All Type I and some Type II  diabetics  are treated with  insulin.  The
long-term side effects of diabetes and of insulin therapy can be severe.

         Dr.  Ullrich was the first to clone the TK  receptor  to which  insulin
binds. In a normal state,  the body secretes  insulin which in turn binds to the
insulin TK. These events activate the insulin TK signalling  pathway,  resulting
in  cellular  uptake of glucose and  glucose  metabolism.  In Type I and Type II
diabetes,  the TK  signalling  mechanism is  impaired.  Certain TPs appear to be
involved  in down  regulating  (dephosphorylating)  the  insulin  TK  signalling
pathway.  SUGEN believes that a small molecule which specifically inhibits these
TPs may increase insulin TK signalling,  thereby  increasing  glucose uptake and
metabolism.

         SUGEN's animal studies with its lead  phosphatase  inhibitor  compounds
have  demonstrated  the ability of its  initial  lead  compounds  to lower blood
glucose  levels with efficacy  comparable to currently  available  drugs.  These
compounds  will serve as the starting  point for  medicinal  chemistry  and drug
development  with the aim of producing an optimized drug candidate to go forward
into clinical  development.  Based on the mechanism of action of these compounds
and  their  oral  availability,  the  Company  believes  that  it  now  has  the
opportunity  to  develop  drug  candidates  for the  treatment  of both  Type II
(non-insulin dependent) and Type I (insulin dependent) diabetes.

Neurology

         TKs, TPs and their  signalling  pathways are known to play key roles in
the  maintenance of the central and peripheral  nervous  systems.  Several known
neurotrophic  factors  bind to TKs,  and thereby  regulate  differentiation  and
survival of neurons.  SUGEN has identified novel TKs and TPs whose expression is
restricted to the nervous system and which may serve as therapeutic  targets for
intervention in neurological diseases.  SUGEN has also identified lead compounds
that  act  as  selective  TP  inhibitors  and  are  able  to  stimulate   neuron
differentiation in in vitro models.

Immunology

         The role of TKs in the generation  and  maintenance of the human immune
system has been established by a number of researchers in different laboratories
around the world.  SUGEN has  developed a number of  immunology  related  assays
which it is  screening  against  its  library of  compounds  and  extracts.  For
example,  ZAP-70,  an intracellular TK, appears to be a primary regulator of the
generation  and  function  of the  T-lymphocyte  cell  population  of the immune
system.  This TK and other signal  transduction  molecules in the immune  system
represent    potential   drug   discovery    targets   for   identifying   novel
immunosuppressive and immuno-modulating  drugs. The primary clinical indications
that the Company is focusing on in immunology are immune  suppression  and acute
inflamation.

SUGEN's Drug Discovery Technology

         SUGEN's goal is to discover and develop drugs that target specific TKs,
TPs, STKs or related  downstream  signalling  molecules.  SUGEN's drug discovery
effort is focused  primarily on the  discovery of small  molecule  drugs derived
from synthetic  compound  libraries and collections of natural product extracts,
including  microbes,  fungi and plants. As compared to biologic  pharmaceuticals
such as  proteins,  peptides  and  carbohydrates,  small  molecules  often offer
advantages as potential  drugs.  Small molecules can more easily  penetrate cell
membranes and the blood brain barrier, can often be delivered orally, and can be
less  immunogenic.  These  molecules  also tend to involve  substantially  lower
process   development  and   manufacturing   costs.   Using   inhibition  of  TK
phosphorylation  in a whole cell environment as an initial screening  criterion,
SUGEN has been able to identify lead  compounds in a number of its programs that
penetrate the cell easily, show minimal  cytotoxicity and demonstrate potent and
selective activity on given targets.

         SUGEN's  process  of  drug  discovery  includes  the  following  steps,
regardless of disease area: (1) target  identification,  using advanced genomics
techniques  and the Company's  proprietary  bioinformatics  program;  (2) target
validation  in relevant in vivo  disease  models;  (3) whole cell or other assay
design and target-driven

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<PAGE>


screening   of   compounds   for  leads;   and  (4)  lead   optimization   using
crystallography  and computational  chemistry.  The Company's  in-house research
teams  also work  closely  with NYU,  MPI and MPP in target  identification  and
target  validation.  In this  case,  the  remaining  steps of this  process  are
conducted primarily by SUGEN or by its corporate partners.

Target Identification

         SUGEN's genomics efforts are focused exclusively on certain families of
signal transduction genes, which make up approximately two percent of the entire
human genome.  These families include the TKs, TPs, STKs,  adaptor molecules and
certain other important molecules involved in cellular  signalling.  Within this
specific area of focus, SUGEN identifies and defines the function of novel genes
and their protein  products,  and in turn assesses  their utility as targets for
therapeutic intervention against diseases of interest to the Company.

         SUGEN  believes  that  substantially  the entire  human  genome will be
sequenced  within a few years,  and most of that sequence data will be available
on  public  databases  or  elsewhere.   SUGEN's  target  identification  effort,
therefore,  is focused on  determining  the  function  of novel  genes.  In this
regard,  SUGEN has made a strategic  commitment to its bioinformatics  platform,
representing a bridge between  abundant gene sequence data and  disease-relevant
discoveries.

         SUGEN's bioinformatics program starts with a physical repository of the
approximately  200 known  signal  transduction  genes in addition to other genes
discovered  by SUGEN but not  published  to date.  SUGEN also has a  proprietary
panel of oligonucleotide primers capable of recognizing genes that are minimally
related  to genes  already  in the SUGEN  library.  All of this  information  is
supported by an in-house massively parallel computer processing platform capable
of approximately 68,000 million instructions per second (mips) throughput. Using
sophisticated pattern recognition algorithms,  SUGEN is able to rapidly mine the
public databases looking for new sequence material of interest, for the complete
sequences of gene fragments  identified  from cells of interest,  for additional
members of newly discovered  families of signal transduction genes, or for human
homologs of genes from lower organisms where genetic studies provide information
pertinent to the function of the new human gene.

         SUGEN  has  developed  a  proprietary  DNA  array  based  hybridization
technology called transcript imaging, for which the Company has filed for patent
protection.  This  technology  enables  SUGEN  researchers  to rapidly  obtain a
comprehensive  analysis of the  expression  level for all TKs and TPs in a small
sample of cell or tissue.  SUGEN's  transcript  imaging  allows  the  Company to
identify  signalling  pathways  that play key roles in specific  cell types and,
more  importantly,  to  compare  diseased  cells  to  healthy  cells in order to
determine where aberrant signalling may play a causative role in a disease.  For
example, if a particular signal transduction gene is heavily  overexpressed in a
significant  proportion of samples of a specific tumor type, that gene becomes a
potential  candidate  for target  validation.  If the gene can  subsequently  be
validated as playing a causative  role in these  tumors,  it may be adopted as a
target for drug  discovery.  SUGEN  believes that this  technology  also has the
potential to become an important diagnostic tool, an opportunity which SUGEN may
seek to  pursue  in  partnership  with an  established  diagnostics  company  or
otherwise.

         Using both in-house  bioinformatics and molecular biology capabilities,
SUGEN and its  collaborators  have  discovered  more than 15 TKs, 15 TPs and 135
STKs for which the Company has filed or intends to file patent applications.

Target Validation

         A primary  challenge  in SUGEN's  target-driven  drug  discovery  is to
progress as efficiently  as possible from  identifying a potential new target to
verifying  that a drug  which  specifically  acts on that  target  could  have a
significant therapeutic benefit in the treatment of a given disease. Within this
process,  "target  validation" is a crucial step before committing  resources to
assay development and screening for  target-specific  drug leads. The first step
in  validating  a  novel  target  usually  involves   developing  a  battery  of
proprietary  reagents,  including truncated or point-mutated  genes,  anti-sense
constructs and  antibodies.  In the case of novel  receptors,  where the natural
ligands and signalling  substrates initially may be unknown, the Company employs
a variety of advanced methods for identifying and cloning these molecules. Using
these  reagents,  the Company then  engineers cell lines in which it has clearly
characterized  the expression levels and activity of the target gene. These cell
lines can then be used to establish in vitro and in vivo whether down-regulating
the  target  will block the  disease  cascade.  If so, the target is  considered
validated.

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<PAGE>


Assay Design/Screening

         From its  inception,  SUGEN  has  committed  significant  resources  to
building  a strong  assay  development  capability.  The  Company  regards  this
capability  as an  important  component  of  its  proprietary  position  in  the
discovery and  development  of  target-specific  signal  transduction  inhibitor
drugs.  Assay  quality  is the  most  important  determinant  of  any  screening
program's  productivity.  This becomes even more important in target-driven drug
discovery.  SUGEN  primarily  employs  engineered  whole cell assays rather than
biochemical   assays.   A  majority   of  SUGEN's   assays  are   designed   for
high-throughput  robotics screening, and its core assay technologies are broadly
applicable to TKs, TPs and STKs and related signalling molecule targets.

         SUGEN's drug discovery process employs a battery of proprietary  assays
and models  engineered  specifically  to ensure  that the target is present  and
functional  in a  consistent  fashion  at each  step of the  screening  cascade.
SUGEN's assays are designed to answer the following four questions:

Screen 1    Can a  compound  block the  signalling  of the  target in  question,
            within the context of a living cell?

Screen 2    Is the  compound  sufficiently  selective  in  blocking  the desired
            target's  signalling (i.e., can it block the target without blocking
            closely related targets)?

Screen 3    Does the compound  exert the desired  biological  effect on a living
            cell (e.g., block cell growth)?

Screen 4    Does the compound  exert the desired  biological  effect  within the
            context of an in vivo disease model?

          By  employing  this  proprietary  screening  cascade,  SUGEN  hopes to
identify  lead  compounds  which are  active in a whole  cell  environment,  are
sufficiently potent and specific to a given target, and are active in an in vivo
disease model which is driven by the given target.

         Once targets are validated by SUGEN and the assays have been  developed
and  validated,  diverse  libraries of  synthetic  small  molecules  and natural
product extracts are screened in order to identify  potential drug leads.  SUGEN
currently has a number of targets  moving through its screening  assays,  and as
new targets are validated SUGEN  continues to add to its panels of assays.  Each
additional assay enhances the Company's  ability to determine the specificity of
lead  compounds.  Along  with  assay  design and  screening,  SUGEN has  devoted
significant  resources to acquiring libraries of structurally  diverse compounds
from a variety of sources around the world.

         Chemical  Compound  Libraries.  SUGEN  has  entered  into a  number  of
agreements designed to obtain chemical compounds for screening. These agreements
cover a broad range of chemical  entities  from  sources  across the world.  The
Company  currently has over 25,000  chemical  compounds  available  in-house for
screening  and has access to a portion of Zeneca's and ASTA  Medica's  libraries
for collaboration targets.

         Natural  Product  Sources.  SUGEN has gained access to  commercial  and
non-commercial  sources  of natural  products,  including  microbial,  plant and
fungal extracts.  These sources  represent an international  collection  network
that provides substantial diversity of material,  including extracts from Japan,
China,  Europe and North America.  The Company is currently  negotiating to gain
access to additional  sources of extracts from different parts of the world. The
Company  currently has over 16,000 natural product extracts  available  in-house
for screening.

Lead Optimization

         The objective of SUGEN's lead  optimization  program is to increase the
potency, specificity and pharmacologic properties of lead compounds by designing
and synthesizing  analogs. Lead optimization uses an iterative process employing
panels  of  assays  to  test  for TK  activity,  TK  specificity,  and  in  vivo
pharmacologic  endpoints  of lead  molecules in order to derive  compounds  with
clinical  utility.  All  results  are  entered  into a database  that allows for
determination  of  structure  and  activity  relationships  leading to synthetic
chemistry efforts that follow important  parameters for drug  development.  This
growing database represents a proprietary source of information on relationships
between  small  molecules,   their  specific  targets,   and  the  pharmacologic
properties  of the compounds  which the Company  believes  will  accelerate  the
optimization of lead compounds in several SUGEN programs.

         SUGEN has recently added  crystallographic  analysis and  computational
chemistry to its drug discovery  process.  Work conducted in Dr.  Schlessinger's
laboratory at NYU, as well as with other collaborators,  allows SUGEN scientists
to elucidate how the Company's product  candidates bind to the catalytic core of
TKs and provides a basis for further  directed  synthetic  chemistry  efforts in
lead optimization, potential development of

                                       12

<PAGE>


second generation  compounds and the development of novel inhibitors against new
targets. In this regard, in a collaboration with ArQule, Inc. ("ArQule"),  SUGEN
used combinatorial chemistry technology closely coordinated with crystallography
data to rapidly synthesize large numbers of analog compounds around SUGEN's lead
compounds. The crystallographic  analysis provides a rationale to identify novel
chemical  templates  that may  provide  a cache of novel  compounds  with  broad
application to the inhibition of TKs and STKs.

         The  Company   believes  that  its  ability  to  improve   potency  and
specificity  in the early  stages of drug  discovery  process and  pharmacologic
features in the later stages of lead  optimization  may reduce the incidence and
severity of side effects and thus may reduce the cost,  time and risk associated
with bringing potential products to market.

Preclinical Development

         Wherever  possible,  SUGEN's in vitro and animal  models  utilize tumor
cell  lines,   reagents  and  techniques  developed  during  target  validation;
therefore,  the  appropriateness  of the model system is already  known prior to
drug testing.  In addition,  many other tools used during target  validation are
used again at this stage of testing. Typically, additional cell lines and animal
models will need to be developed in order to enable the accurate assessment of a
compound's target-specific activity in an in vivo environment.

Corporate and Clinical Development Collaborations

         The Company's  approach to corporate  partnering is different in cancer
than it is in other disease areas. In the cancer field, SUGEN intends to build a
vertically  integrated oncology business in North America, with the objective of
bringing to market a family of target-specific  signal  transduction  inhibitors
proprietary to SUGEN. To market its products effectively,  the Company currently
intends to build a focused U.S. sales force to target the major cancer treatment
centers. The Company plans to seek additional corporate partners to fund product
development and commercialize its products in Europe and Asia. While the Company
generally  intends to retain  rights to its cancer  programs  in North  America,
SUGEN  is  funding  a  portion  of  its  ongoing  cancer   research   through  a
collaboration  with  Zeneca  for  the  development  of five  undisclosed  cancer
targets.  Pursuant to its  agreement  with  Zeneca,  the  Company  will have the
opportunity to obtain profit  participation  rights in the North American market
by  contributing  to clinical  development  costs as incurred  and will  receive
milestone  payments and royalties on worldwide sales.  Outside of oncology,  the
Company's  strategy is to seek  corporate  collaborations  or joint  ventures to
which SUGEN contributes validated targets, screening technologies and drug leads
while the partner provides the disease-specific  and drug development  expertise
as well as  marketing  experience,  in  addition to  providing  funding to bring
potential products to market. As part of this strategy, the Company entered into
a  collaboration  with  Allergan  for  angiogenesis   inhibition  in  ophthalmic
applications resulting from the Company's Flk-1/KDR TK antagonist program.

Zeneca Limited

         In January 1995, the Company established a research  collaboration with
Zeneca.  In this  collaboration,  Zeneca and the Company  seek to  discover  and
develop novel small molecule signal transduction inhibitors that address certain
substantial  oncology markets.  The collaboration covers five undisclosed cancer
programs, but excludes all programs upon which the Company is currently building
its own cancer business. The two companies have agreed upon specific programs to
be included initially in the collaboration,  with Zeneca supporting SUGEN's work
on these  programs  for an initial  term of five years.  SUGEN  performs  target
identification,  target validation,  assay development and screening for initial
leads,   while  Zeneca  scientists   concentrate  on  lead   identification  and
optimization and preclinical and clinical  development  activities.  Zeneca will
market collaboration  products worldwide.  SUGEN has also granted Zeneca a right
of first  negotiation  to  expand  this  collaboration  in  order  to  encompass
additional SUGEN cancer research  projects,  but has  specifically  excluded the
cancer related projects that SUGEN already has in development.

         Under the terms of the agreement,  Zeneca  purchased  789,141 shares of
Common  Stock  at a price  of  $15.84  per  share.  This  $12.5  million  equity
investment, combined with Zeneca's $7.5 million participation in SUGEN's October
1994 initial public  offering,  increased  Zeneca's  ownership in the Company to
approximately  20%. Zeneca has committed not to increase its holdings above this
level without the approval of SUGEN's Board of Directors. Zeneca participated in
the  Company's  September  1995,  October  1996 and  November  1997  financings,
purchasing an additional 281,875, 509,000 and 456,000 shares,  respectively,  of
Common Stock in order to maintain its ownership  position.  To date,  Zeneca has
invested approximately $36.8 million in the Company's Common Stock.

         In addition to its equity purchases and annual research funding, Zeneca
paid a $5.0  million  technology  set-up fee to SUGEN,  and will make  milestone
payments (which may be offset against royalties over time) tied

                                       13

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to the progress of compounds in the  collaboration,  and  royalties on worldwide
sales  of any  collaboration  products.  SUGEN  will  also  have  the  right  to
contribute  to  clinical  development  costs on each  program,  thereby  earning
participation in the North American profits from successful  products coming out
of such programs over and above its royalty entitlement. Apart from this option,
Zeneca  will be  responsible  for all  development  expenses.  If a third  party
acquires  35% or  more  of  SUGEN's  voting  stock,  Zeneca  may  terminate  the
collaboration  agreement but retain exclusive  royalty-bearing license rights to
any collaboration  products for which IND filing preparations are complete and a
separate  license  agreement has been  executed.  There can be no assurance that
this  collaboration will result in any milestones being achieved or any products
being successfully developed.

         The agreement provides for SUGEN to be granted access to Zeneca's large
proprietary  collection  of  characterized  chemical  structures  for  screening
against  SUGEN's  signal  transduction  targets,  both within and  outside  this
collaboration,  subject to certain  restrictions  and a right of first licensing
negotiation  on  Zeneca's  part.  Zeneca has granted to SUGEN the right of first
negotiation  to  license  from  Zeneca  oncology   products  (other  than  those
specifically  excluded under the agreement) which Zeneca decides to license to a
third party.

         In January 1996,  SUGEN licensed a small molecule  inhibitor of the EGF
TK from Zeneca.  The compound,  SU5271, was licensed from Zeneca as an extension
of the original  collaboration  agreement  SUGEN  signed with Zeneca.  Under the
terms of this license agreement, Zeneca granted to SUGEN an exclusive, worldwide
license,  with right to sublicense  the compound,  in exchange for milestone and
royalty payments.  The agreement  provides that SUGEN shall have overall control
and  responsibility  for the  preclinical and clinical  development,  regulatory
strategy, process development and commercialization of SU5271.

National Cancer Institute

         In April 1996, the Company  entered into a  Collaborative  Research and
Development  Agreement  ("CRADA") with the National Cancer Institute (the "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.  Following this transcript imaging analysis of the panel,
the results will be correlated to the data generated over several decades at the
NCI from the  screening  each year of many  thousands of  compounds  and natural
extracts  against  the panel.  Interesting  lead  compounds  from the NCI's open
repository  collection  will  be  tested  in  SUGEN's   target-specific   signal
transduction  assays,  and lead compounds from SUGEN will also 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.

ASTA Medica Aktiengesellschaft

         In December 1995, SUGEN and ASTA Medica entered into a collaboration to
research,  develop,  manufacture,   market  and  distribute  potential  oncology
products  based  upon  the  Company's  Pan-Her  antagonist  and  Raf  antagonist
programs.  Under the terms of the collaboration,  ASTA Medica will undertake the
medicinal  chemistry  and  pharmaceutical   development  work  on  SUGEN's  drug
candidates,  and will perform preclinical and clinical  development in Europe in
accordance with FDA standards.  ASTA Medica paid SUGEN a $4.0 million technology
set-up fee and is  providing  additional  consideration  in the form of services
provided by ASTA Medica pursuant to the collaboration  but on  non-collaboration
programs.  Additionally, ASTA Medica purchased $9.0 million of Common Stock at a
price of $20.88 per share. In January 1998, SUGEN and ASTA Medica proceeded into
clinical  development  with their  Pan-Her  cancer  program,  marking  the first
milestone in SUGEN's  collaborations with ASTA Medica. ASTA Medica exercised its
option to satisfy its milestone  obligation by the purchase of $500,000 of SUGEN
common stock at a price of  approximately  $26.79 per share of which the premium
above fair  market  value was  recorded as  revenue.  In due  course,  SUGEN may
receive  additional   milestone  payments  in  the  two  programs  if  they  are
successful.  The  agreement  provides  for  ASTA  Medica  to  receive  exclusive
marketing  rights  to  collaboration   products  in  Greater  Europe  (including
countries and territories located in the former Soviet Union) and South America,
subject to an obligation to pay  royalties on net sales in such  territories  to
SUGEN.  ASTA Medica also has the right of first offer to manufacture  product to
be sold in SUGEN territories.  SUGEN retains marketing rights in the rest of the
world, subject to a royalty payable to ASTA Medica in most circumstances.

         ASTA Medica is an international pharmaceutical company headquartered in
Germany.   The  Company's   research  and  development  is  focused  on  cancer,
respiratory   diseases/allergies   and   disorders   of  the   central   nervous
system/epilepsy. The company is owned by Degussa, a German company active in the
fields of  chemicals,  health and  nutrition,  as well as banking  and  precious
metals.

                                       14

<PAGE>


Allergan

         In October 1996,  SUGEN entered into a  collaboration  with Allergan to
identify,  develop  and  commercialize  novel  angiogenesis  inhibitors  for the
treatment  of  ophthalmic  diseases.  The  collaboration  aims  to  establish  a
comprehensive  effort to identify and validate signal  transduction  targets for
choroidal and retinal  neovascularization.  Allergan is the exclusive  corporate
partner for SUGEN in ocular  diseases of  neovascularization  and has  exclusive
rights  to all  ophthalmic  uses of  collaboration  products  and  collaboration
know-how  worldwide.  In return,  Allergan paid SUGEN a $2.0 million initial fee
for past  research  services  and is  funding  collaboration  research  and drug
discovery at SUGEN for at least three years.  Allergan initially  purchased $4.0
million of Common Stock at $20.88 per share and purchased an additional  250,000
shares of Common  Stock at $12.00 per share in SUGEN's  October  1996  follow-on
offering.   SUGEN  will  also  receive  payments  upon  achievement  of  certain
milestones  and  royalties  with  respect to  worldwide  sales of  collaboration
products.  In  addition,  SUGEN will have the right to  contribute  to  clinical
development  costs on each program,  thereby earning  participation in the North
American  and  European  profits  from  successful  products  coming out of such
programs  over and above  its  royalty  entitlement.  Apart  from  this  option,
Allergan will be responsible for all development expenses.

Research Collaborations

         SUGEN's scientific  founders are Dr. Joseph  Schlessinger,  Chairman of
the  Department of  Pharmacology  at NYU, and Dr. Axel Ullrich,  Director of the
Department of Molecular Biology at MPI in Martinsried,  Germany.  In the fall of
1991,  the Company  entered into  research  collaboration  agreements  with both
institutions.  More  recently the Company has  established  additional  research
collaborations relating to TPs, TKs and STKs identification and screening areas.

New York University Medical Center

         In September 1991, SUGEN entered into a research and license  agreement
with NYU granting the Company an exclusive  worldwide  license to the commercial
uses of TK, TP and STK technology being developed at NYU under the leadership of
Dr.  Schlessinger.  The research  program  being  conducted at NYU centers on an
investigation  of the mechanisms  underlying the action of TKs, TPs and STKs and
their physiological role, as well as identifying, isolating and cloning new TKs,
TPs and STKs and the components of the signal  transduction  pathways  emanating
from  these  proteins.  The  research  program is  scheduled  to expire in 2001.
SUGEN's license to technology  developed  before or during the research  program
will survive indefinitely unless NYU terminates the agreement upon insolvency of
the Company or due to a material breach by the Company. Upon such termination of
the  agreement,  NYU will  continue to own the rights to the  technology  it has
developed under the agreement.  The Company is obligated to pay royalties to NYU
on sales of any SUGEN  products  for which an IND is filed  within four years of
the end of the NYU research period except for certain in-licensed  products.  As
part of this arrangement,  NYU purchased 200,000 shares of SUGEN Common Stock at
the Company's formation.

Max-Planck Society

         SUGEN has formed research collaborations with two institutes of the MPS
in Germany.  These collaborations include licenses from Garching Innovation GmbH
("Garching"), the licensing arm of MPS.

         Max-Planck-Institut fur Biochemie.  The Company entered into a research
and license  agreement with MPI and Garching which expired in August 1997 but is
expected to be  extended  in  modified  form.  This  agreement  grants  SUGEN an
exclusive worldwide license to the commercial uses of TK and TP technology being
developed at MPI under the leadership of Dr. Ullrich.  The scope of the research
program includes identification, isolation and cloning of novel receptor TKs and
TPs,   characterization   of  signal   transduction   pathway   components   and
investigation  of the normal  biological role of these proteins as well as their
role in disease.  SUGEN's license to technology  developed  before or during the
research program will survive  indefinitely  unless MPI terminates the agreement
upon insolvency of the Company or due to a material breach by the Company.  Upon
such  termination of the  agreement,  MPI will continue to own the rights to the
technology it has developed under the agreement. The Company is obligated to pay
royalties  on sales  of any  products  using  this  technology.  As part of this
arrangement,  MPS currently owns 200,000 shares of SUGEN Common Stock  purchased
at the Company's formation.

         Max-Planck-Institut  fur  Physiologische  und Klinische  Forschung.  In
October 1993,  SUGEN entered into an agreement  with MPP and Garching to support
the work of Dr. Werner Risau, a leading  researcher in the area of angiogenesis.
This agreement grants SUGEN the exclusive  worldwide right to commercialize  Dr.
Risau's  research on the inhibition of  angiogenesis,  vasculogenesis,  vascular
permeability, chemotaxis and

                                       15

<PAGE>


neurite outgrowth.  This research  collaboration will terminate in October 1999.
SUGEN's license to technology  developed  before or during the research  program
will survive indefinitely unless MPP terminates the agreement upon insolvency of
the Company or due to a material breach by the Company.  Upon termination of the
agreement,  MPP will own the rights to the technology it has developed under the
agreement.  The Company is obligated  to pay  royalties on sales of any products
embodying this technology.

ArQule

         In September 1996,  SUGEN entered into a  collaboration  agreement with
ArQule to develop a  proprietary  collection  of  compounds  designed  to target
binding   sites  common  to  many  signal   transduction   molecules   found  in
cell-signalling  pathways.  SUGEN  provided  lead  chemical  structures  and new
chemical  structure  scaffolds  which enabled  ArQule to use its Directed  Array
combinatorial  synthesis  technologies to build a novel  collection of compounds
with  potentially  broad  applications  for  the  pharmaceutical  industry.  The
research  program expired in September 1997.  SUGEN retains  exclusive rights to
this collection with respect to TK and STK targets,  subject to certain payments
and royalties to ArQule.  ArQule retains  responsibility for commercializing the
collection for targets in other areas,  subject to royalty-sharing  arrangements
with SUGEN.

Other Sources of Materials for Screening

         The Company has entered into a number of agreements  designed to obtain
novel  biochemical  and  biological  compounds and extracts for screening in its
proprietary  assay  systems.  These  agreements  cover a broad range of chemical
entities  from  sources  across the  world.  SUGEN  also has an  agreement  with
Panlabs,  Inc. of Bothell,  Washington  for the supply of  microbial  and fungal
extracts and the isolation and  identification  of active  components from these
extracts. The original agreement was entered into in March 1993 and is renewable
for  successive  one year periods.  The  agreement  most recently was amended in
early 1997,  under which  Panlabs  will  supply the Company  with a  significant
number of extracts  from which the Company can select a portion to be designated
as "selected organisms." SUGEN will own all rights to the selected organisms and
the active compounds  produced by them,  including any  derivatives.  Panlabs is
supplying other  companies with similar  extracts under similar  conditions.  In
June  1995,  SUGEN  and  Toyama  Prefectural  University  of Tokyo  initiated  a
collaboration  to  discover  new drugs  for the  treatment  of cancer  and other
diseases by inhibiting TKs and TPs and related molecules. A research team headed
by Professor Toshikazu Oki in the University's  Biotechnology Research Center is
providing to SUGEN  compounds  from  Toyama's  microbial  strain  libraries  for
testing of potential biological activity. In July 1996, SUGEN and the Institutes
of  Botany  and  Microbiology  of the  Chinese  Academy  of  Sciences  initiated
exclusive   collaborations  to  discover  novel  signal  transduction  inhibitor
candidates  and  pharmacophores.  The  Institute of Botany and the  Institute of
Microbiology  have  provided to SUGEN  extracts from the  Institutes'  plant and
microbial  collections  for testing of  potential  biological  activity  against
SUGEN's  signal  transduction  targets.  Other SUGEN  compound  sources  include
natural product libraries from around the globe, including microbial, fungal and
plant extracts, as well as additional sources of small organic compounds.

Patents and Proprietary Technology

         The  Company's  success  will  depend in part on its  ability to obtain
patents,   maintain  trade  secrets  and  operate  without   infringing  on  the
proprietary rights of others,  both in the United States and in other countries.
Patent matters in biotechnology,  and in particular with respect to receptors as
screening  tools and/or the DNA encoding them, are highly  uncertain and involve
complex  legal and  factual  questions.  Accordingly,  the  availability  of and
breadth of claims allowed in biotechnology and pharmaceutical  patents cannot be
predicted.  As of December 31, 1997,  SUGEN held exclusive rights to at least 16
issued  U.S.  patents,   had  exclusive  rights  to  at  least  15  U.S.  patent
applications  for which  notices of allowance had been  received,  and had filed
and/or  held  exclusive  licenses  to  approximately  120 United  States  patent
applications,  as well as related foreign patent applications. In December 1997,
the Company  received two U.S.  patents  relating to methods of using SU101. The
Company also has received a patent  relating to formulations  comprising  SU101.
There can be no assurance  that the Company  will develop  products or processes
that  are  patentable,   that  patents  will  issue  from  any  of  the  pending
applications, or that claims allowed will be sufficient to protect the Company's
technology.  There can be no assurance  that the Company's  patents,  if issued,
will not be challenged,  invalidated or circumvented, or that the rights granted
thereunder will provide proprietary  protection or competitive advantages to the
Company.  Competitors have been issued patents,  may have filed  applications or
may obtain  additional  patents and  proprietary  rights relating to products or
processes  competitive  with  those of the  Company  or which  could  block  the
Company's efforts to obtain patents.

         A  number  of  pharmaceutical   companies,   biotechnology   companies,
universities  and  research  institutions  have  filed  patent  applications  or
received  patents  in the  field of TKs,  TPs and STKs  and  related  downstream
signalling molecules.  The commercial success of the Company will depend in part
on SUGEN not  infringing  patents  issued to  competitors  and not breaching the
technology licenses upon which any Company

                                       16

<PAGE>


products are based.  The Company in the past has been,  and from time to time in
the future may be, notified of claims that the Company may be infringing patents
or other  intellectual  property  rights owned by third parties.  Certain patent
applications  or patents of the  Company's  competitors  may  conflict  with the
Company's  patents  and  patent  applications,  and  SUGEN is aware  that  other
companies have filed patent  applications  and have been granted  patents in the
United States and other countries  claiming subject matter potentially useful or
necessary to the Company. Such conflicts could result in a significant reduction
in the scope of the coverage of the  Company's  issued or licensed  patents.  In
addition,  if patents are issued to other companies which contain competitive or
conflicting  claims and such claims are ultimately  determined to be valid,  the
Company  may be required  to obtain  licenses to these  patents or to develop or
obtain  alternative  technology.  If any licenses are required,  there can be no
assurance  that  the  Company  will  be able  to  obtain  any  such  license  on
commercially favorable terms, if at all, and if these licenses are not obtained,
the Company might be prevented  from pursuing the  development of certain of its
potential  products.  The Company's  breach of an existing license or failure to
obtain a license to any  technology  that it may  require to  commercialize  its
products may have a material  adverse impact on the Company.  Litigation,  which
could  result in  substantial  costs to the  Company,  may also be  necessary to
enforce any patents  issued or licensed to the Company or to determine the scope
and validity of third-party  proprietary rights.  There can be no assurance that
the  Company's  issued or  licensed  patents  would be held  valid by a court of
competent jurisdiction. Even if the outcome of such litigation is favorable, the
cost of such litigation and the diversion of the Company's  management resources
during such litigation could have a material  adverse effect on the Company.  An
adverse  outcome could subject the Company to  significant  liabilities to third
parties,  require  disputed  rights to be licensed from third parties or require
the Company to cease using such  technology,  any of which could have a material
adverse effect on the Company.  If  competitors of the Company  prepare and file
patent  applications in the United States that claim  technology also claimed by
the Company,  the Company may have to  participate in  interference  proceedings
declared by the Patent and Trademark Office to determine  priority of invention,
which could  result in  substantial  cost to the  Company,  even if the eventual
outcome is  favorable  to the  Company.  Indeed,  the Company  has several  such
interferences pending. When patents issue in certain areas such as Japan and the
European community,  third parties can oppose such issuance. Should the relevant
patent  office  institute a  proceeding  termed an  opposition,  the Company may
decide to defend its patent.  There can be no assurance that the Company will be
successful  or that the  patent  office  will not revoke the patent or alter the
scope of protection previously granted.

         SU101, a compound generally known by the name leflunomide,  is a member
of the isoxazole  family of compounds.  Leflunomide  was discovered more than 17
years ago. A large  pharmaceutical  company  holds a number of United States and
foreign  patents  and has filed  applications  in the  United  States and abroad
covering  compositions  of matter and  pharmaceutical  uses of  leflunomide  and
structurally  related  compounds.  As noted  above,  SUGEN has received two U.S.
patents  containing claims relating to the use of SU101 in treating certain PDGF
TK related cancers and tumors.  While the Company  believes at this time that it
will receive method of use patent protection outside the United States on SU101,
there can be no assurance that any such patent protection will be issued.  SUGEN
believes its research and  development and its clinical trials with SU101 in the
United States are  protected  from claims of  infringement  of the United States
patents because such  activities are being conducted  solely for uses reasonably
related to  development  and submission of information to the FDA for regulatory
approval.  Similar  protection  may not be available  outside the United States.
Although the Company  cannot  predict  whether or when SU101 will be approved by
the FDA for  marketing  in the United  States,  it believes  that certain of the
pharmaceutical  company's  patents in the United  States may have  expired  when
marketing does begin and that the remaining  U.S.  patents are either invalid or
will not be infringed by the manufacture and sale of SU101 in the United States.
However,  the Company has learned  that  additional  patents  have issued in the
United States to the pharmaceutical  company covering the use of leflunomide and
structurally  related compounds for the treatment of named cancers.  The Company
presently  does  not know if  commercialization  of SU101  will  infringe  these
additional  patents but believes that the  additional  patents may be subject to
claims of invalidity  as they relate to SU101.  If the  additional  patents were
determined  to be valid with  respect to SU101,  the  Company may be required to
obtain a license from the  pharmaceutical  company in order to  manufacture  and
sell SU101 in the United  States.  There can be no assurance that SU101 will not
infringe  the  recently  issued  patents,  that the  term of the  pharmaceutical
company's  other existing  patents will not be extended,  that the claims of the
pharmaceutical  company's pending patent applications will not be modified prior
to issuance so as to enhance their validity or scope, or that a court will agree
with the Company's  beliefs  regarding  invalidity and  non-infringement  of the
patents.  To date,  the  pharmaceutical  company has not threatened or commenced
legal proceedings against the Company concerning  possible patent  infringement.
There can be no assurance that the pharmaceutical company in the future will not
assert claims  against SUGEN or that the Company could reach  agreement with the
pharmaceutical  company for a license for SU101 upon favorable  terms or at all,
if  required.  The  inability of the Company to resolve this matter on favorable
terms or at all could  have a material  adverse  effect on the  Company.  In any
event,  the  assertion  of any such  claims,  even if resolved  favorably to the
Company, could result in substantial costs to the Company.

                                       17

<PAGE>


         The Company plans to  commercialize  SU101 in the major markets outside
the  United  States  either  through  affiliates  or  through   licensees,   and
anticipates  receiving  similar  patent  protection  in Europe  and Japan to its
Unites  States  position.  The scope,  term and  validity of the  pharmaceutical
company's  patent  protection  outside the United  States is different  than the
situation in the United States,  and the Company's  ability to  manufacture  and
sell SU101  outside the United  States may be adversely  impacted by this patent
protection.

         SUGEN also relies on trade  secrets to protect  technology,  especially
where patent  protection is not believed to be appropriate or obtainable.  SUGEN
attempts  to  protect  its  proprietary  technology  and  processes  in  part by
confidentiality   agreements   with  its  employees,   consultants  and  certain
contractors.  There  can be no  assurance  that  these  agreements  will  not be
breached,  that the Company would have adequate remedies for any breach, or that
the Company's trade secrets will not otherwise  become known or be independently
discovered by competitors.  To the extent that the Company or its consultants or
research  collaborators use intellectual  property owned by others in their work
for the  Company,  disputes  may  also  arise as to the  rights  in  related  or
resulting know-how and inventions.

Competition

         SUGEN is  engaged  in a rapidly  changing  field.  Other  products  and
therapies  that will  compete  directly  with the  products  that the Company is
seeking  to  develop  and  market   currently  exist  or  are  being  developed.
Competition from fully integrated  pharmaceutical companies and more established
biotechnology  companies is intense and is expected to  increase.  Most of these
companies  have  significantly  greater  financial  resources  and  expertise in
research and  development,  manufacturing,  conducting  preclinical  studies and
clinical trials,  obtaining regulatory approvals and marketing than the Company.
Many of these  competitors have significant  products that have been approved or
are in  development  and operate  large,  well-funded  research and  development
programs.  For example,  monoclonal  antibodies  targeting  Her2,  including one
developed by Dr. Ullrich, are currently in clinical trials by others for certain
cancers.  Smaller  companies  may  also  prove  to be  significant  competitors,
particularly  through  collaborative  arrangements with large pharmaceutical and
established   biotechnology  companies.   Academic  institutions,   governmental
agencies  and other  public and  private  research  organizations  also  conduct
research,  seek patent protection and establish  collaborative  arrangements for
products  and  clinical   development   and  marketing.   These   companies  and
institutions  compete  with the  Company  in  recruiting  and  retaining  highly
qualified scientific and management  personnel.  Competition may also arise from
companies  pursuing  differing  technological  approaches  to cancers  and other
disease indications targeted by the Company's product candidates. In addition to
the above factors,  SUGEN will face  competition  based on product  efficacy and
safety,  the timing and scope of regulatory  approvals,  availability of supply,
marketing  and  sales  capability,  reimbursement  coverage,  price  and  patent
position.  There is intense  competition  for access to and use of  libraries of
compounds  to use for  screening  and any  inability  of the Company to maintain
access to  sufficiently  broad  libraries of compounds for  screening  potential
targets  would  have a  material  adverse  effect  on the  Company.  There is no
assurance that the Company's competitors will not develop more effective or more
affordable  products,  compete more  effectively  for corporate  partnerships or
achieve earlier patent protection or product commercialization than the Company.

Government Regulation

         The  Company's  ongoing  research and  development  activities  and the
manufacturing and marketing of the Company's  potential  products are subject to
extensive regulation by numerous  governmental  authorities in the United States
and other  countries.  Failure to comply with applicable FDA or other applicable
regulatory  requirements  may result in criminal  prosecution,  civil penalties,
recall or seizure of products,  total or partial  suspension  of  production  or
injunction,  as well as other  regulatory  action  against  the  Company  or its
potential products.

         Prior to  marketing  in the United  States,  any drug  developed by the
Company must undergo  rigorous  preclinical  studies and clinical  trials and an
extensive  regulatory clearance process implemented by the FDA under the federal
Food, Drug and Cosmetic Act. Satisfaction of such regulatory requirements, which
includes  satisfying  the FDA  that the  product  is both  safe  and  effective,
typically  takes several years or more depending  upon the type,  complexity and
novelty of the product and requires the  expenditure of  substantial  resources.
The Company is focusing its initial development efforts related to SU101 for the
treatment of malignant glioma and selected other solid tumor patient populations
with very poor  prognosis.  Given the poor  prognoses  for these  patients,  the
Company  believes  that FDA  approval  could  potentially  be obtained  based on
smaller-scale  clinical trials than are typically required for approval of NDAs.
There can be no  assurance,  however,  that the Company  will be able to rely on
smaller-scale  clinical  trials to expedite the  commercialization  of SU101 for
these patient populations.

                                       18

<PAGE>


         Preclinical studies must be conducted in conformance with the FDA's GLP
regulations.  Before commencing  clinical trials, the Company must submit to and
receive  approval  from  the  FDA of an  IND.  There  can be no  assurance  that
submission  of an IND would  result in FDA  authorization  to commence  clinical
trials.  Clinical trials must meet requirements for  institutional  review board
oversight,  informed  consent and good  clinical  practice  requirements  and is
subject  to  continuing  FDA  oversight.  The  Company  does not have  extensive
experience in conducting and managing the clinical  testing  necessary to obtain
regulatory approval. Clinical trials may require large numbers of test subjects.
Furthermore,  the Company or the FDA may suspend  clinical trials at any time if
they believe that the subjects participating in such trials are being exposed to
unacceptable  health  risks or if the FDA finds  deficiencies  in the IND or the
conduct of the trials.

         Before  receiving FDA  clearance to market a product,  the Company will
have to  demonstrate  that the  product  is safe and  effective  on the  patient
population  that will be treated.  Data  obtained from  preclinical  studies and
clinical  trials are susceptible to varying  interpretations  which could delay,
limit or prevent regulatory clearances. In addition, delays or rejections may be
encountered based upon additional  government regulation from future legislation
or  administrative  action or changes in FDA policy during the period of product
development,  clinical trials and FDA regulatory review. Similar delays also may
be encountered in foreign  countries.  There can be no assurance that even after
such  time  and  expenditures  regulatory  clearance  will be  obtained  for any
products  developed  by the  Company.  If  regulatory  clearance of a product is
granted,  such  clearance will be limited to those disease states and conditions
for which the  product is useful,  as  demonstrated  through  clinical  studies.
Marketing  or  promoting  a drug for an  unapproved  indication  is  prohibited.
Furthermore,   clearance  may  entail  ongoing  requirements  for  postmarketing
studies.  Even if such regulatory clearance is obtained, a marketed product, its
manufacturer  and its  manufacturing  facilities are subject to continual review
and periodic  inspections by the FDA.  Discovery of previously  unknown problems
with a product,  manufacturer  or facility  may result in  restrictions  on such
product or  manufacturer,  including  costly  recalls or even  withdrawal of the
product from the market.  There can be no assurance that any compound  developed
by the  Company  alone or in  conjunction  with others will prove to be safe and
efficacious in clinical  trials and will meet all of the  applicable  regulatory
requirements needed to receive marketing clearance.

         Manufacturers  of drugs and biologics  also are required to comply with
the  applicable  FDA good  manufacturing  practice  ("GMP")  regulations,  which
include  requirements  relating to quality control and quality assurance as well
as the  corresponding  maintenance of records and  documentation.  Manufacturing
facilities  are  subject  to  inspection  by  the  FDA,  including   unannounced
inspection,  and  must  be  licensed  before  they  can be  used  in  commercial
manufacturing  of the  Company's  products.  There can be no assurance  that the
Company  or its  suppliers  will be able  to  comply  with  the  applicable  GMP
regulations  and other FDA  regulatory  requirements.  Such failure could have a
material adverse effect on the Company.

         The   Company   may  elect  to  seek   approval   of  SU101  under  the
Clinton-Kessler  Cancer  Initiative.  Significant  uncertainty  exists as to the
extent to which such initiative will result in accelerated  review and approval.
Further, the FDA has not made available comprehensive guidelines with respect to
this initiative,  retains considerable  discretion to determine  eligibility for
accelerated  review  and  approval  and is not  bound  by  discussions  that  an
applicant  may have had with FDA staff.  Accordingly,  the FDA could employ such
discretion to deny eligibility of SU101 as a candidate for accelerated review or
to require  additional  clinical trials or other  information  before  approving
SU101.  A  determination  that SU101 is not eligible for  accelerated  review or
delays and additional expenses associated with generating a response to any such
request  for  additional  trials  could  have a material  adverse  effect on the
Company.

         Outside the United States, the Company's ability to market a product is
contingent  upon  receiving  a  marketing  authorization  from  the  appropriate
regulatory  authorities.  The  requirements  governing  the  conduct of clinical
trials,  marketing  authorization,  pricing and  reimbursement  vary widely from
country to country. At present, foreign marketing authorizations are applied for
at a national  level,  although  within the European  Community  ("EC")  certain
registration  procedures are available to companies  wishing to market a product
in more than one EC member state. If the regulatory  authority is satisfied that
adequate  evidence  of  safety,  quality  and  efficacy  has been  presented,  a
marketing  authorization  will be  granted.  This  foreign  regulatory  approval
process includes all of the risks associated with FDA clearance set forth above.

Manufacturing

         The  Company  has no  manufacturing  facilities  and  relies  on  other
manufacturers to produce its compounds for research and development, preclinical
studies and clinical trials.  The products under development by the Company have
never been manufactured for large-scale  clinical trials or commercial purposes,
and there can be no assurance that such products can be  manufactured  at a cost
or in  quantities  necessary  for  large-scale  clinical  trials or to make them
commercially viable. Any change in the Company's existing relationships with, or
interruption in supply from, its manufacturers of the compounds used in its

                                       19

<PAGE>


clinical  trials could affect  adversely the  Company's  ability to complete its
ongoing clinical trials and to market its product candidates,  if approved.  Any
such change or interruption  may have a material  adverse effect on the Company.
In the event of a change in the  supplier  of a  compound  used in its  clinical
trials,  the Company would be required to collect data from its ongoing clinical
trials with  respect to a compound  and file such data with the FDA to establish
clinical  comparability between the compound as produced by different suppliers.
There can be no  assurance  that the  Company  would be able to  establish  such
clinical comparability. A failure to establish clinical comparability could lead
to a requirement that the Company enlarge the size of an ongoing clinical trial,
which  would  delay  the  completion  of  such  trial,  increase  its  cost  and
potentially  delay the Company's  pursuit of  regulatory  approval for a product
candidate. If the Company were unable to contract for a sufficient supply of its
compounds on acceptable  terms, or if it should encounter delays or difficulties
in its relationships with manufacturers,  the Company's  preclinical studies and
clinical trial  schedule would be delayed,  resulting in delay in the submission
of products for regulatory  approval or the market  introduction  and subsequent
sales of such  products,  which  could  have a  material  adverse  effect on the
Company.  Moreover,  contract manufacturers that the Company may use must adhere
to current GMP regulations enforced by the FDA through its facilities inspection
program.  If these facilities cannot pass a pre-approval  plant inspection,  the
FDA pre-market approval of the products will not be granted.

Employees

         As of December  31,  1997,  the Company  had 189  full-time  employees,
including a technical scientific staff of 138. The Company places an emphasis on
obtaining the highest  available  quality of staff. The Company has selected and
assembled a group of  experienced  scientists and managers with skills in a wide
variety   of   disciplines,   including   molecular   biology,   chemistry   and
pharmaceutical development. To date, the Company believes it has been successful
in its efforts to recruit qualified employees, but there is no assurance that it
will continue to be as successful in the future. None of the Company's employees
are covered by collective  bargaining  arrangements,  and  management  considers
relations with its employees to be good.

                                       20

<PAGE>


Item 2.         PROPERTIES

         SUGEN currently leases  approximately  60,000 square feet of laboratory
and office  space in Redwood  City,  California.  The Company  leases this space
under  operating   leases  which  last  through   November  and  December  1998.
Approximately  48,000 square feet of the laboratory  and office space  currently
under lease have three- and five-year renewal options at the end of the leases.

         In June 1997, the Company entered into a  build-to-suit  facility lease
agreement  with  respect  to a  new  research  and  headquarters  facilities  of
approximately 106,000 square feet on a site in South San Francisco,  California.
Construction  of the new facility is targeted for  completion  during the fourth
quarter of 1998,  which  coincides with the expiration of the Company's  current
facility  leases.  See  "Management's   Discussion  and  Analysis  of  Financial
Condition   and  Results  of   Operations."   The  Company   believes  that  the
build-to-suit  facility,  in addition to its options for additional space at the
South San  Francisco  site,  will be  sufficient  to meet its needs for the next
several  years.  There can be no  assurances,  however,  that such space will be
available on favorable terms, if at all.


Item 3.         LEGAL PROCEEDINGS

SUGEN is not a party to any material legal proceedings.


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

None.

                                       21

<PAGE>


                                     PART II


Item 5. MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS

         Since the  Company's  initial  public  offering of its common  stock in
October 1994,  the Company's  Common Stock has traded on the Nasdaq Stock Market
under the symbol SUGN.  The following  table lists the high and low sales prices
for the  Company's  Common  Stock for each quarter of fiscal year 1997 and 1996.
These prices do not include retail markups, markdowns or commissions.

                                     -----------------------------------
                                               High               Low
- ------------------------------------------------------------------------
1997
Fourth Quarter                           $     21.13         $     12.63
Third Quarter                                  20.94               11.88
Second Quarter                                 13.25               10.00
First Quarter                                  15.25                9.88
- ------------------------------------------------------------------------
1996
Fourth Quarter                                 14.50               11.25
Third Quarter                                  12.75                9.38
Second Quarter                                 15.25               11.25
First Quarter                            $     15.88         $     11.75
- ------------------------------------------------------------------------


         As of March 13, 1998 there were  approximately 229 holders of record of
the Company's  Common Stock.  On March 13, 1998, the last sale price reported on
the Nasdaq National Market System for the Company's  Common Stock was $14.50 per
share.

         The Company has not paid any dividends since its inception and does not
intend to pay any dividends on its Common Stock in the foreseeable future.

                                       22

<PAGE>


Item 6.          SELECTED FINANCIAL DATA

<TABLE>
Statement of Operations Data:
(in thousands, except per share data)

<CAPTION>
                                                                                  Year Ended December 31,
                                                           ------------------------------------------------------------------------
                                                             1997            1996            1995           1994             1993
                                                           --------        --------        --------        --------        --------
<S>                                                        <C>             <C>             <C>             <C>             <C>     
Contract revenue (1)                                       $  6,031        $ 13,650        $ 13,843        $  6,270        $  5,470
Costs and expenses:
        Research and development                             34,585          29,792          23,226          17,079          10,251
        General and administrative                            6,227           5,529           5,086           3,106           2,169
                                                           --------        --------        --------        --------        --------
             Total costs and expenses                        40,812          35,321          28,312          20,185          12,420
                                                           --------        --------        --------        --------        --------
Operating loss                                              (34,781)        (21,671)        (14,469)        (13,915)         (6,950)
Other income and expense:
        Interest income                                       2,786           2,481           1,988             529             339
        Interest expense                                     (1,065)           (691)           (494)           (278)            (56)
        Gain on sale of investment
           in Selectide Corporation                            --              --             1,006            --              --   
                                                           --------        --------        --------        --------        --------
             Other income, net                                1,721           1,790           2,500             251             283
                                                           --------        --------        --------        --------        --------
Net loss                                                   $(33,060)       $(19,881)       $(11,969)       $(13,664)       $ (6,667)
                                                           ========        ========        ========        ========        ========

Basic and diluted net loss per share (2)                   $  (2.47)       $  (1.81)       $  (1.32)       $  (4.37)       $  (4.84)
                                                           ========        ========        ========        ========        ========

Shares used in computing basic and diluted
        net loss per share (2)                               13,387          10,966           9,085           3,129           1,378
                                                           ========        ========        ========        ========        ========

Pro forma net loss per share (3)                                                                           $  (2.27)       $  (1.49)
                                                                                                           ========        ========

Shares used in computing pro forma net loss per share (3)                                                     6,013           4,485
                                                                                                           ========        ========
</TABLE>


<TABLE>
Balance Sheet Data:
(in thousands)
<CAPTION>
                                                                                           December 31,
                                                               --------------------------------------------------------------------
                                                                 1997           1996           1995           1994           1993
                                                               --------       --------       --------       --------       --------
<S>                                                            <C>            <C>            <C>            <C>            <C>     
Cash, cash equivalents and
        short-term investments                                 $ 75,295       $ 56,334       $ 53,253       $ 22,414       $ 16,984
Total assets                                                   $ 84,825       $ 61,936       $ 59,243       $ 28,455       $ 20,812
Senior custom convertible notes                                $ 17,500       $   --         $   --         $   --         $   --   
Capital lease obligations - non-current portion                $  3,152       $  2,938       $  3,651       $  2,087       $    441
Accumulated deficit                                            $(90,988)      $(57,997)      $(37,964)      $(26,270)      $(12,451)
Stockholders' equity                                           $ 49,013       $ 48,530       $ 43,441       $ 18,319       $ 13,230

<FN>
(1)  Includes amounts from related party.
(2)  Basic and diluted loss per share for 1994 and 1993 have been  retroactively
     restated to apply the  requirements  of Staff  Accounting  Bulletin  No. 98
     ("SAB  98"),  issued by the SEC in  February  1998.  Under SAB 98,  certain
     shares of common  stock and  options and  warrants  to  purchase  shares of
     common  stock at prices  substantially  below the per share price of shares
     sold in the Company's  initial public offering  previously  included in the
     computation of shares outstanding  pursuant to Staff Accounting  Bulletin's
     Nos. 55, 64 and 83 are now excluded from the computation.
(3)  Pro forma net loss per share  information gives effect to the conversion of
     all preferred stock outstanding from the date of issuance.
</FN>
</TABLE>

                                       23

<PAGE>


Item 7. MANAGEMENT'S  DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

         The following  discussion  and analysis  should be read in  conjunction
with "Selected Financial Data" and the Company's Financial  Statements and Notes
thereto  included  elsewhere in this Annual Report on Form 10-K.  Except for the
historical information contained herein, the discussion in this Annual Report on
Form 10-K contains  certain  forward-looking  statements  that involve risks and
uncertainties,   such  as  statements  of  the  Company's   plans,   objectives,
expectations and intentions.  These forward-looking  statements are based on the
current  expectations  of the Company,  and the Company assumes no obligation to
update this information. The cautionary statements made in this Annual Report on
Form 10-K  should be read as being  applicable  to all  related  forward-looking
statements  wherever  they  appear  in this  Annual  Report  on Form  10-K.  The
Company's  actual results could differ  materially  from those  discussed  here.
Factors  that  could  cause or  contribute  to such  differences  include  those
discussed under "Liquidity & Capital Resources" below as well as those discussed
elsewhere herein.

Overview

         SUGEN was founded in July 1991 to  discover  and develop new classes of
small  molecule  drugs  which  target  specific  cellular  signal   transduction
pathways.  These  signalling  pathways  are involved in a variety of chronic and
acute  pathological  diseases,  including  cancer  and  diabetes  as  well as in
dermatologic,  ophthalmic,  neurologic and immune disorders.  The Company's most
advanced  product  candidate  is SU101,  a PDGF TK  signalling  antagonist.  The
Company has completed the data analysis on a Phase II clinical  trial for use of
SU101 as a treatment for refractory  malignant  glioma and initiated a Phase III
clinical  trial  during the first  quarter of 1998. A Phase II study of SU101 in
combination  with  BCNU,  the  chemotherapy  drug  that is part of the  standard
treatment  regimen in newly diagnosed brain cancer patients and a Phase II study
in hormone  refractory  prostate cancer was initiated  during the second half of
1997.  To date,  approximately  158  patients,  including  patients  with brain,
ovarian,  prostate and non-small cell lung cancers, have been treated with SU101
in nine  Company-sponsored  clinical trials.  The Company is also conducting its
initial Phase I clinical trial for its second cancer product candidate,  SU5416,
a Flk-1/KDR TK  antagonist  which  inhibits  angiogenesis  (the process by which
blood  vessels are  formed).  In addition,  the Company is  conducting a Phase I
clinical trial for SU5271,  an EGF  antagonist,  for the treatment of psoriasis.
Through December 31, 1997,  substantially  all of the Company's revenue has been
earned pursuant to collaborations  with Zeneca Limited  ("Zeneca"),  ASTA Medica
Aktiengesellschaft ("ASTA Medica"), Vision Pharmaceuticals L.P., an affiliate of
Allergan,  Inc., and Allergan,  Inc.  (collectively  "Allergan")  and Amgen Inc.
("Amgen").   The  Company   intends  to  pursue  its  drug  discovery   programs
independently and in collaboration with established pharmaceutical companies.

         In September 1997, the Company  completed a private  placement of $17.5
million principal amount of 5% Senior Custom Convertible Notes due 2000. The net
proceeds to the Company were approximately $16.3 million.

         In  November  1997,  the  Company  completed  a  follow-on  offering of
2,000,000  shares  of  Common  Stock at a price of  $16.00  per  share.  The net
proceeds to the Company  were  approximately  $29.7  million.  Zeneca  purchased
456,000 shares of Common Stock in the offering.

         The  Company has not been  profitable  since  inception  and expects to
incur  substantial  losses  for the  foreseeable  future,  primarily  due to the
expansion of  preclinical  and clinical  development  activities  as more of its
proprietary  cancer-related  programs  progress toward and into the clinic.  The
Company expects that losses will fluctuate from quarter to quarter and that such
fluctuations  may  be  substantial.  As of  December  31,  1997,  the  Company's
accumulated deficit was $91.0 million.

Results of Operations

         The Company's revenues for the years ended December 31, 1997, 1996, and
1995 were $6.0 million, $13.7 million, and $13.8 million, respectively. Revenues
for the year ended December 31, 1997 included contract

                                       24

<PAGE>

revenue  from the  Allergan  and Zeneca  collaborations  and contract & services
revenue earned under the ASTA Medica collaboration for services provided by ASTA
Medica pursuant to the collaboration but on non-collaboration programs. In 1998,
the Company expects to fully utilize the remaining available credit for contract
services  provided by ASTA Medica and  thereafter  will only  recognize  revenue
under  the  ASTA  Medica   collaboration   upon  the  achievement  of  specified
milestones. The Company is actively pursuing additional  collaborations,  but no
assurance  can be  given  as to  the  ability  of  the  Company  to  enter  such
collaborations on a timely basis, or at all.

         Revenues for 1996  included an up-front  fee and contract  revenue from
the Allergan collaboration,  contract revenue from the Zeneca collaboration, the
recognition of the balance of 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  revenues from
set-up and wind-down  fees as the related  activities  are  performed,  which is
generally over a twelve-month period or less. The decrease in 1997 revenues from
1996 was due to the  recognition of set-up and wind-down fees from the Allergan,
ASTA Medica and Amgen  collaborations  in 1996. No such fees were  recognized in
1997.

         Research  and  development  expenses  for the years ended  December 31,
1997,  1996 and 1995 were  $34.6  million,  $29.8  million  and  $23.2  million,
respectively.  The increase  during 1997 was primarily  due to higher  personnel
related  costs  associated  with the  expansion  of the  Company's  research and
development  programs.  In addition,  the  progression  of clinical  activities,
including  expanded  Phase  I  and  Phase  II  studies  of  the  Company's  lead
anti-cancer  compound,  SU101,  initiation  of Phase I studies of the  Company's
psoriasis  program,  SU5271,  and Phase I studies of the Company's second cancer
product candidate,  SU5416, contributed to higher expenses during 1997. Further,
the advancement of multiple programs through preclinical development,  including
activities  associated with the Company's June 1997 filing of an Investigational
New Drug  ("IND")  with the U.S.  Food and Drug  Administration  ("FDA") for the
clinical testing of SU5416,  led to higher expenses in 1997. The increase during
1996 was driven by expenses  associated with additional  personnel  dedicated to
the Company's research and development programs. In addition, the progression of
clinical activities, including expanded Phase I studies of SU101, contributed to
the  growth  in 1996  expenses.  The  Company  expects  that  its  research  and
development  expenses will continue to grow in future years due to the hiring of
personnel,  additional  preclinical studies, the progression of SU101 and SU5416
clinical  trials,  the  initiation  of new clinical  trials on  additional  drug
candidates and pursuant to requirements  under the Company's  anticipated future
collaborations.

         General and  administrative  expenses for the years ended  December 31,
1997,  1996 and  1995  were  $6.2  million,  $5.5  million,  and  $5.1  million,
respectively. The increase in 1997 was primarily due to higher headcount related
costs as well as  additional  expenses  in the areas of investor  relations  and
business  development.  The  increase  in 1996 was  primarily  due to  increased
administrative  staffing,  the related  recruiting and  relocation  expenses and
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 expanding research and development efforts.

         Interest  income for the years ended December 31, 1997,  1996, and 1995
was $2.8 million, $2.5 million, and $2.0 million, respectively.  These increases
were due to higher  investment  balances arising primarily from issuances of the
Company's  capital stock and convertible  debt.  Interest  expense for the years
ended December 31, 1997, 1996 and 1995 was $1.1 million, $691,000, and $494,000,
respectively.  These increases were primarily due to the Company's continued use
of capital lease  financing for equipment and property  improvements  related to
the expansion of its facilities.  The Company expects that interest expense will
continue to increase in future years due to the  continued  use of capital lease
financing for equipment and facility  improvements and the added expense related
to the issuance of senior custom  convertible notes in September 1997,  provided
the debt is not  converted.  A $1.0  million  gain on the sale of the  Company's
investment  in  Selectide  was  included in other  income  during the year ended
December 31, 1995.

         The  Tax  Reform  Act  of  1986  contains  provisions  that  limit  the
utilization of net operating loss and tax credit carryforwards if there has been
a "change in  ownership"  as described  in Section 382 of the  Internal  Revenue
Code.  Such a change in ownership  may have arisen as a result of the  Company's
initial public offering or subsequent sales of securities.

                                       25

<PAGE>


Liquidity and Capital Resources

         At  December  31,  1997,  the Company had cash,  cash  equivalents  and
short-term   investments   of   approximately   $75.3   million   compared  with
approximately  $56.3  million at December  31,  1996.  The  increase in cash and
investments  during the year ended  December 31, 1997 was  primarily  due to the
$31.2 million in net proceeds  from the issuance of Common Stock,  $16.3 million
in net  proceeds  received in  connection  with the  issuance  of senior  custom
convertible  notes in September 1997,  partially  offset by the net loss for the
year.

         Through December 31, 1997, the Company's principal sources of financing
have been its initial and follow-on public offerings of Common Stock, placements
of the Company's Preferred and Common Stock and senior custom convertible notes,
and funds received under the Company's corporate  collaborations.  The Company's
current  principal  sources  of  liquidity  are  its  research  and  development
collaborations with ASTA Medica, Zeneca and Allergan, its cash, cash equivalents
and short-term investments and capital lease financing. The Company has combined
capital lease lines of $6.4 million  available for the purchase of equipment and
facility   improvements  at  December  31,  1997,  including  the  $5.0  million
additional lease line secured in November 1997.

         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 the  agreements  may  require  the Company to make
milestone and royalty payments.  Under these programs,  commitments for external
research funding are approximately $1.7 million,  $1.6 million, $1.4 million and
$1.1  million  in  1998,  1999,  2000  and  2001,  respectively.  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.  The Company anticipates renewing certain contracts that
expired  in 1997  which  will  increase  future  commitments  beyond  the levels
indicated above for 1998 through 2001.

         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 1998. 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 years
ended December 31, 1997, 1996, and 1995 were $3.2 million, $1.7 million and $2.6
million,  respectively,  which  included  $1.4  million,  $1.3  million and $2.6
million,  respectively, of equipment and leasehold improvements financed through
the Company's master lease agreements. In general,  additions for 1997, 1996 and
1995  included  facility  expansion  costs,  the  continued  enhancement  of the
Company's  laboratory  capabilities  and the costs associated with the Company's
ongoing effort to maintain an up-to-date  technology base. Additions in 1997 and
1996  also  included  the  purchase  of a mass  spectrometer  and a  significant
investment in computer  hardware and software to support the Company's  genomics
and  bioinformatics  programs,  respectively.  Under  these  capital  leases and
certain  operating  lease   arrangements,   including  the  build-to-suit  lease
agreement,  the Company has lease commitments of $20.0 million through 2002. The
Company intends to fund future capital  expenditures  principally  through lease
financing or other debt  arrangements,  although  there can be no assurance that
such financing will be available. The Company expects that its capital additions
for 1998 will be higher than that of the prior year primarily due to anticipated
facility  improvements  in  connection  with the  build-to-suit  facility  lease
agreement which was entered into in June 1997.  Construction of the new facility
is targeted for completion  during the fourth quarter of 1998,  which  coincides
with the  expiration  of the Company's  current  facility  leases.  Although the
Company has not expended  significant  amounts to date,  the Company  expects to
invest in facility  improvements  and incur move related costs during 1998 as it
approaches building completion.  Accordingly,  it is expected that the Company's
capital  lease  obligations  and  related  interest  expense,  as  well  as  its
depreciation expense, will increase in future periods. See "Properties."

         The Company estimates that its existing capital resources together with
facility and equipment financing,  expected revenues from current collaborations
and net income from investment activities, will be

                                       26

<PAGE>


sufficient to fund its planned  operations into 2000.  However,  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 Year 2000 Issue is the result of computer  programs  being  written
using two digits  rather than four  digits to define the  applicable  year.  The
Company has reviewed its existing software programs for year 2000 compliance and
believes  that  all  of  its  internal  application  systems  are  currently  in
compliance.  The Company plans to initiate formal communications with all of its
significant suppliers to determine the extent to which the Company is vulnerable
to those third  parties'  failure to remediate  their own Year 2000 Issues.  The
project  is  estimated  to be  completed  early  1999,  which  is  prior  to any
anticipated  impact on its operations.  The Company does not expect the costs of
year  2000  compliance  to have a  material  impact on the  Company's  financial
results.  However,  there can be no assurance that all third parties,  including
clinical  trial  sites,  with whom the  Company  works  will  achieve  year 2000
compliance on a timely basis for systems related to their  interactions with the
Company,  or that failure to achieve year 2000  compliance by such entities will
not 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 three
drug candidates  (SU101,  SU5271 and SU5416) have entered  clinical  trials.  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.  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.  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.  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.  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  uncertainties  regarding protection of patents and
proprietary  rights,  government  regulation,   competition,   employee  issues,
manufacturing   uncertainties,   the  Company's  lack  of  sales  and  marketing
capabilities,  uncertainty of market acceptance of the Company's  products,  and
uncertainties regarding pharmaceutical pricing and reimbursement.

                                       27

<PAGE>


Item 8. FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

The  response  to this Item is  submitted  in a separate  section of this report
beginning on page F-1.


Item 9.  CHANGES  IN  AND  DISAGREEMENTS  WITH  ACCOUNTANTS  ON  ACCOUNTING  AND
         FINANCIAL DISCLOSURE

Not applicable.

                                       28

<PAGE>


                                    PART III


Item 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

         Glenn S.  Utt,  Jr.  resigned  from the  Company's  Board of  Directors
effective  January 5, 1998 for personal  reasons.  The Company is retaining  Mr.
Utt's services as a consultant to the Chairman at least until December 31, 1998.

         The information required by this item is incorporated by reference from
the  information  under the captions  "ELECTION OF DIRECTORS"  and  "MANAGEMENT"
contained in the Company's  definitive proxy statement to be filed no later than
April 30, 1998 in connection with the  solicitation of proxies for the Company's
Annual Meeting of Stockholders to be held May 20, 1998 (the "Proxy Statement").

Item 11. EXECUTIVE COMPENSATION

         The information required by this item is incorporated by reference from
the  information  under  the  caption  "EXECUTIVE  COMPENSATION"  of  the  Proxy
Statement.

Item 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

         The information required by this item is incorporated by reference from
the  information  under the caption  "SECURITY  OWNERSHIP OF CERTAIN  BENEFICIAL
OWNERS AND MANAGEMENT" in the Proxy Statement.

Item 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

         The information required by this item is incorporated by reference from
the information under the caption "CERTAIN TRANSACTIONS" in the Proxy Statement.

                                       29

<PAGE>


                                     PART IV


<TABLE>
Item 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES AND REPORTS ON FORM 8-K

<CAPTION>
(a)

     1.  Financial Statements                                                                  Page
                                                                                               ----
<S>                                                                                             <C>
     The  following  financial  statements  of SUGEN,  Inc.  are  included  in a
separate section of this report:

         Balance Sheets at December 31, 1997 and 1996                                           F-3

         Statements of Operations for each of the three years in the period
           ended December 31, 1997                                                              F-4

         Statement of Stockholders' Equity for each of the three years in the
           period ended December 31, 1997                                                       F-5

         Statements of Cash Flows for the three years in the period
           ended December 31, 1997                                                              F-6

         Notes to Financial Statements                                                          F-7
</TABLE>

     2.  Financial Statement Schedules

     All schedules have been omitted as they are not required,  not  applicable,
     or the required  information  is included in the  financial  statements  or
     notes thereto.

                                       30

<PAGE>


     3.  Exhibits

  Exhibit
   Number         Exhibit
   ------         -------
    3.1           Restated  Certificate  of  Incorporation,  filed  February 23,
                  1995. (2)
    3(ii).2       Bylaws of the Registrant. (1)
    3.3           Certificate of  Designation  of Series A Junior  Participating
                  Preferred Stock of the Registrant. (5)
    4.1           Reference is made to Exhibits 3.1 through 3(ii).2.
    4.2           Specimen Stock Certificate. (1)
    4.3           Form of 5% Senior Custom Convertible Note due 2000. (15)
    4.4           Form of Common Stock Purchase Warrant. (15)
   10.1           Form of Investor  Rights  Agreement,  dated December 23, 1992,
                  among the Registrant and certain investors. (1)
   10.2           Registrant's  1992 Amended and Restated Stock Option Plan (the
                  "Option Plan"), as amended. (11)
   10.3           Form of Incentive Stock Option under the Option Plan. (1)
   10.4           Form of Nonstatutory Stock Option under the Option Plan. (1)
   10.5           Warrant to Purchase 2,666 Shares of Series A Preferred  Stock,
                  dated  December 7, 1991,  granted by the  Registrant  to Sanwa
                  Business Credit Corp. (1)
   10.6           Warrant to Purchase 2,666 Shares of Series A Preferred  Stock,
                  dated  December 7, 1991,  granted by the Registrant to Silicon
                  Valley Bancshares. (1)
   10.7           Warrant to Purchase 5,333 Shares of Series A Preferred  Stock,
                  dated  December 7, 1991,  granted by the Registrant to Western
                  Technology Investment. (1)
   10.8           Warrant to Purchase 133,333 Shares of Common Stock, dated July
                  13, 1992, granted by the Registrant to Genentech, Inc. (1)
   10.9           Warrant  Agreement  to  Purchase  40,000  Shares  of  Series D
                  Preferred   Stock,   dated  October  30,  1992,   between  the
                  Registrant and Comdisco, Inc. (1)
   10.10          Warrant  Agreement to Purchase Shares of Series G(F) Preferred
                  Stock,  dated  July  23,  1993,  between  the  Registrant  and
                  Comdisco, Inc. (1)
   10.11          Warrant  Agreement to Purchase Shares of Series G(F) Preferred
                  Stock,  dated  July  23,  1993,  between  the  Registrant  and
                  Comdisco, Inc. (1)
   10.12          Stock Swap Agreement, dated July 27, 1992, as amended, between
                  the Registrant and Selectide Corporation. (1)
   10.13++        Amended and  Restated  Research and License  Agreement,  dated
                  August      16,      1991,      among     the      Registrant,
                  Max-Planck-Gesellschaft,   Max-Planck-Institut   and  Garching
                  Innovation GmbH; and Extension, dated March 31, 1993. (1)
   10.14++        Amended and  Restated  Research and License  Agreement,  dated
                  September  1,  1991,  between  the  Registrant  and  New  York
                  University. (1)
   10.15++        Services and Supply Agreement,  dated January 1, 1992, between
                  the Registrant and BioSignal, Ltd. (1)
   10.15(i)       Exhibit A to Services and Supply  Agreement,  dated January 1,
                  1992, between the Registrant and BioSignal, Ltd. (1)
   10.16++        Collaboration and License Agreement,  dated November 17, 1992,
                  between the Registrant and Selectide Corporation. (1)
   10.17++        Collaboration Agreement,  dated December 18, 1992, between the
                  Registrant and Amgen, Inc. (1)
   10.17(i)++     Amendment  Number One to Collaboration  Agreement  between the
                  Registrant and Amgen, Inc., dated June 15, 1995. (3)
   10.18          Letter of Intent,  dated May 27, 1993,  among the  Registrant,
                  the  State  Science &  Technology  Commission  of the  Peoples
                  Republic of China,  and  International  Technology  Investment
                  Managers (Asia), Inc. (1)
   10.19++        Amended and Restated Research and License  Agreement,  between
                  the Registrant and Yissum Research  Development Company of The
                  Hebrew University of Jerusalem, dated March 27, 1995. (2)
   10.20++        Research and License  Agreement,  dated October 1, 1993, among
                  the Registrant,  Max-Planck-Institut  and Garching  Innovation
                  GmbH. (1).

                                       31

<PAGE>


  Exhibit
   Number         Exhibit
   ------         -------
   10.21++        Exclusive License  Agreement,  dated January 21, 1994, between
                  the Registrant and Washington Research Foundation. (1)
   10.22          Purchase  Agreement between the Registrant and Zeneca Limited,
                  dated October 4, 1994. (2)
   10.23++        Amended and Restated  Research and License  Agreement  between
                  the Registrant and Yissum Research  Development Company of The
                  Hebrew University of Jerusalem (labeled "Psoriasis"). (8)
   10.24++        Amended and Restated  Research and License  Agreement  between
                  the Registrant and Yissum Research  Development Company of The
                  Hebrew University of Jerusalem (labeled "Papilloma"). (8)
   10.25++        Amended and Restated  Research and License  Agreement  between
                  the Registrant and Yissum Research  Development Company of The
                  Hebrew       University       of      Jerusalem       (labeled
                  "Sepsis/Inflammation"). (8)
   10.26++        Amended and Restated  Research and License  Agreement  between
                  the Registrant and Yissum Research  Development Company of The
                  Hebrew University of Jerusalem (labeled "Restenosis"). (8)
   10.27          Consulting  Agreement,  dated  August 16,  1991,  between  the
                  Registrant and Dr. Joseph Schlessinger. (1)
   10.28          Consulting  Agreement,  dated  August 16,  1991,  between  the
                  Registrant and Dr. Axel Ullrich. (1)
   10.29          Seaport  Centre  Standard Lease and Addendum I, dated November
                  12, 1991,  between the  Registrant  and Seaport Center Venture
                  Phase I. (1)
   10.29(i)       First  Amendment,  dated  July  8,  1993,  to  Seaport  Centre
                  Standard  Lease  between the  Registrant  and  Seaport  Center
                  Venture Phase I. (1)
   10.29(ii)      Second  Amendment,  dated  June 2,  1995,  to  Seaport  Centre
                  Standard  Lease  between the  Registrant  and  Seaport  Centre
                  Venture Phase I. (3)
   10.29(iii)     Construction Addendum, dated June 2, 1995, to Second Amendment
                  to Seaport  Centre  Standard  Lease between the Registrant and
                  Seaport Centre Venture Phase I. (3)
   10.30          Registrant's 1994 Employee Stock Purchase Plan. (1)
   *10.31         Registrant's 1994  Non-Employee  Directors' Stock Option Plan,
                  as amended. (11)
   10.32          Form of  Indemnity  Agreement  to be entered  into between the
                  Registrant and its officers and directors. (1)
   10.33          Warrant  Agreement  to  Purchase  7,200  Shares  of  Series  G
                  Preferred Stock, dated May 5, 1994, between the Registrant and
                  Financing for Science International, Inc. (1)
   10.34++        Research and License Agreement,  dated August 1, 1994, between
                  the Company and the Hospital for Sick Children. (1)
   10.34(i)       Amendment  to  Research  and  License  Agreement  between  the
                  Registrant and the Hospital for Sick Children, dated August 1,
                  1995. (4)
   10.35          Research  and  Technology  Agreement,  dated  March  3,  1993,
                  between the Registrant and PanLabs, Inc., as amended. (1)
   10.36++        Collaboration  Agreement,  between the  Registrant  and Zeneca
                  Limited, dated March 22, 1995. (2)
   10.37          Agreement  for the Purchase of Common Stock of the  Registrant
                  by Zeneca Limited, dated January 6, 1995. (2)
   10.38          Loan Agreement and Promissory  Note between the Registrant and
                  James L. Tyree, dated August 29, 1994. (3)
   10.39          Deferred  Compensation  Agreement  between the  Registrant and
                  James L. Tyree, dated August 29, 1994. (3)
   10.40++        Cooperative  Research and  Development  Agreement  between the
                  Registrant and the National Cancer Institute, dated August 14,
                  1995. (4)
   *10.41         Registrant's  1995 Long-Term  Objectives Stock Option Plan for
                  Senior Management, as amended. (12)
   10.42          Form  of   Nonstatutory   Stock  Option  under  the  Long-Term
                  Objectives Stock Option Plan for Senior Management. (6)

                                       32

<PAGE>


  Exhibit
   Number         Exhibit
   ------         -------
   10.43          Rights  Agreement,  dated as of  August 1,  1995  between  the
                  Registrant  and The First  National Bank of Boston,  as Rights
                  Agent. (5)
   10.44          Form of  Agreement  for the  Purchase  of Common  Stock of the
                  Registrant and list of participants  thereto,  dated September
                  21, 1995. (4)
   10.45          Lease Financing  Commitment  Letter,  dated September 12, 1995
                  between   the    Registrant    and   Financing   for   Science
                  International, Inc. (4)
   10.46++        Collaboration  Agreement,  between  the  Registrant  and  ASTA
                  Medica Aktiengesellschaft, dated December 5, 1995. (7)
   10.47          Agreement  for the Purchase of Common Stock of the  Registrant
                  by ASTA Medica Aktiengesellschaft, dated December 5, 1995. (7)
   10.48++        Termination  and Redemption  Agreement  between the Registrant
                  and Amgen Inc., dated January 9, 1996. (8)
   10.49++        Warrant  to  purchase  200,000  shares of Common  Stock of the
                  Registrant,  dated January 19, 1996,  issued by the Registrant
                  to Amgen Inc. (8)
   10.50++        License  Agreement  between the Registrant and Zeneca Limited,
                  dated January 19, 1996. (8)
   10.51++        Cooperative  Research and  Development  Agreement  between the
                  Registrant and the National Cancer Institute,  dated April 12,
                  1996. (9)
   10.52++        Termination notice, dated May 24, 1996, between the Registrant
                  and  Yissum  Research   Development   Company  of  The  Hebrew
                  University of Jerusalem (labeled "Sepsis/Inflammation"). (9)
   10.53++        Termination notice, dated May 24, 1996. between the Registrant
                  and  Yissum  Research   Development   Company  of  The  Hebrew
                  University of Jerusalem (labeled "Restenosis"). (9)
   10.54++        Research and Development  Agreement between the Registrant and
                  Arqule, Inc. (10)
   10.55++        Extension  of  Research  and  License  Agreement  between  the
                  Registrant and the Max Planck Institute. (10)
   10.56          Promissory  Note  received  by  the  Registrant  from  Stephen
                  Evans-Freke. (10)
   10.57          Agreement  for the purchase of Common Stock of the  Registrant
                  by Vision Pharmaceuticals L.P. (10)
   10.58++        Collaboration  Agreement  by and  between the  Registrant  and
                  Vision Pharmaceuticals L.P. and Allergan, Inc. (10)
   10.59++        Extension of Research  Agreement  between the  Registrant  and
                  Yissum Development Company of the Hebrew University. (10)
   10.60          James L. Tyree Separation Agreement. (10)
   10.61++        Master  Lease  Agreement,  dated March 28,  1997,  between the
                  Registrant and Transamerica Business Credit Corporation. (13)
   10.62++        Lease  Financing  Commitment  Letter,  dated  March 20,  1997,
                  between  the  Registrant  and  Transamerica   Business  Credit
                  Corporation. (13)
   10.63++        Build-To-Suit  Lease Agreement,  dated June 11, 1997,  between
                  the Registrant and Britannia Pointe Grand Limited Partnership.
                  (14)
   10.64++        Form of Warrant for the Purchase of Common  Stock,  dated June
                  30, 1997,  issued in the connection with  Build-To-Suit  Lease
                  Agreement,  between the Registrant and Britannia  Pointe Grand
                  Limited Partnership. (14)
   10.65++        Second  Amended and Restated  Research and License  Agreement,
                  dated  June 30,  1997,  between  the  Registrant  and New York
                  University. (14)
   10.66++        Termination notice, dated June 1, 1997, between the Registrant
                  and  Yissum  Research   Development   Company  of  The  Hebrew
                  University of Jerusalem. (14)
   10.67++        Form of Note  Purchase  Agreement,  dated as of  September  8,
                  1997, by and between the  Registrant  and the investors  named
                  therein. (16)
   10.68+         Amended and Restated  Master Lease  Agreement,  dated November
                  12,  1997,  and  Lease  Financing   Commitment  Letter,  dated
                  November 5, 1997,  between  the  Registrant  and  Transamerica
                  Business Credit Corporation.
   *10.69         Restricted Stock Bonus Agreement between the Registrant and K.
                  Peter Hirth, Ph D., dated September 16, 1997.

                                       33

<PAGE>


  Exhibit
   Number         Exhibit
   ------         -------
   23.1           Consent of Ernst & Young LLP, Independent Auditors.
   24.1           Power of Attorney  (incorporated  in the signature page of the
                  Form 10-K).
   27             Financial Data Schedule.

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

   *              Compensatory Plan.
   +              Confidential  Treatment  has been  requested  with  respect to
                  portions of this Exhibit.
   ++             Confidential   treatment  has  previously   been  granted  for
                  portions of this Exhibit.
   (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 on Form 10-K for the year  ended  December  31,
                  1994.
   (3)            Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended June 30, 1995.
   (4)            Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended September 30, 1995.
   (5)            Filed as an exhibit to the Form 8-K Current  Report dated July
                  26, 1995 and incorporated herein by reference.
   (6)            Filed as an exhibit to the Registrant's Registration Statement
                  on Form  S-8 (No.  33-99152),  dated  November  9,  1995,  and
                  incorporated herein by reference.
   (7)            Incorporated  by reference to  identically  numbered  exhibits
                  filed  in  response  to Item 14  "Exhibits"  of the  Company's
                  Annual  Report on Form  10-K as  amended,  for the year  ended
                  December 31, 1995.
   (8)            Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended March 31, 1996.
   (9)            Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended June 30, 1996.
   (10)           Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended September 30, 1996.
   (11)           Filed as an exhibit to the Registrant's Registration Statement
                  on Form  S-8  (No.  333-09323),  dated  August  1,  1996,  and
                  incorporated herein by reference.
   (12)           Filed as an exhibit to the Registrant's Registration Statement
                  on Form  S-8  (No.  333-09321),  dated  August  1,  1996,  and
                  incorporated herein by reference.
   (13)           Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended March 31, 1997.
   (14)           Incorporated  by reference to  identically  numbered  exhibits
                  filed in response to Item 6 "Exhibits" of the  Company's  Form
                  10-Q for the quarter ended June 30, 1997.
   (15)           Filed  as an  exhibit  to the Form 8-K  Current  Report  dated
                  September 12, 1997, and incorporated herein by reference.
   (16)           Filed as an exhibit to the Registrant's Registration Statement
                  on Form S-3, dated October 10, 1997, and  incorporated  herein
                  by reference.

                                       34

<PAGE>


Item 14.  EXHIBITS,  FINANCIAL  STATEMENT  SCHEDULES  AND  REPORTS  ON FORM  8-K
         (continued)


(b)    Reports on Form 8-K

         SUGEN,  Inc. filed a Current Report on Form 8-K dated October 27, 1997,
in connection with the proposed follow-on public offering of Common Stock by the
Company.

         Additionally,  the  Company  filed a  Current  Report on Form 8-K dated
November 19, 1997, in connection  with the follow-on  public  offering of Common
Stock by the Company.

                                       35

<PAGE>







                           Annual Report on Form 10-K

                   ITEM 8, ITEM 14(a)(1) and (2), (c) and (d)

                   Financial Statements and Supplementary Data

                                Certain Exhibits

                          Year Ended December 31, 1997

                                   SUGEN, Inc.

                            Redwood City, California








                                       F-1

<PAGE>


                REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS




The Board of Directors and Stockholders
SUGEN, Inc.

         We have audited the  accompanying  balance sheets of SUGEN,  Inc. as of
December  31,  1997  and  1996,  and  the  related   statements  of  operations,
stockholders'  equity,  and cash flows for each of the three years in the period
ended December 31, 1997. These financial  statements are the  responsibility  of
the Company's  management.  Our responsibility is to express an opinion on these
financial statements based on our audits.

         We conducted our audits in accordance with generally  accepted auditing
standards.  Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements.  An audit also includes
assessing the  accounting  principles  used and  significant  estimates  made by
management,  as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.

         In our opinion,  the  financial  statements  referred to above  present
fairly,  in all material  respects,  the  financial  position of SUGEN,  Inc. at
December 31, 1997 and 1996, and the results of its operations and its cash flows
for each of the three years in the period ended  December 31, 1997 in conformity
with generally accepted accounting principles.


                                                          ERNST & YOUNG LLP


Palo Alto, California
February 5, 1998

                                       F-2

<PAGE>


<TABLE>
                                                            SUGEN, Inc.

                                                           BALANCE SHEETS
                                         (In thousands, except share and per share amounts)

<CAPTION>
                                                                                                   December 31,         December 31,
                                                                                                       1997                 1996
                                                                                                     ---------            ---------
<S>                                                                                                  <C>                  <C>      
ASSETS
Current assets:
        Cash and cash equivalents                                                                    $  23,816            $  24,852
        Short-term investments                                                                          51,479               31,482
        Accounts receivable                                                                                237                  264
        Prepaid expenses and other current assets                                                          754                  468
                                                                                                     ---------            ---------
                Total current assets                                                                    76,286               57,066

Property and equipment, net                                                                              4,601                4,095
Other assets                                                                                             3,938                  775
                                                                                                     ---------            ---------
                                                                                                     $  84,825            $  61,936
                                                                                                     =========            =========

LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
        Accounts payable                                                                             $   1,991            $     852
        Accrued liabilities                                                                             10,267                7,406
        Deferred revenue                                                                                   625                  375
        Capital lease obligations - current portion                                                      2,277                1,835
                                                                                                     ---------            ---------

                Total current liabilities                                                               15,160               10,468

Capital lease obligations - non-current portion                                                          3,152                2,938
Senior custom convertible notes                                                                         17,500                 --   
                                                                                                     ---------            ---------
                Total long-term liabilities                                                             20,652                2,938

Commitments

Stockholders' equity:
        Preferred stock, $.01 par value; 20,000,000 shares
          authorized, issuable in series; 300,000 shares designated
          as Series A Junior Participating Preferred Stock; none
          issued and outstanding                                                                          --                   --   
        Common stock, $.01 par value; 30,000,000 shares
          authorized; shares issued and outstanding:
          15,307,146 and 12,993,450 in 1997 and 1996, respectively                                         153                  130
        Additional paid-in capital                                                                     141,426              107,990
        Deferred compensation                                                                             (695)                (710)
        Note receivable from stockholder                                                                  (883)                (883)
        Accumulated deficit                                                                            (90,988)             (57,997)
                                                                                                     ---------            ---------
                Total stockholders' equity                                                              49,013               48,530
                                                                                                     ---------            ---------
                                                                                                     $  84,825            $  61,936
                                                                                                     =========            =========


<FN>
                                                      See accompanying notes.
</FN>
</TABLE>

                                                                 F-3

<PAGE>


<TABLE>
                                                            SUGEN, Inc.

                                                      STATEMENTS OF OPERATIONS
                                         (In thousands, except share and per share amounts)
                                                                                        

<CAPTION>
                                                                                        
                                                                                              Years Ended December 31,
                                                                               ----------------------------------------------------
                                                                                   1997                1996                1995
                                                                               ------------        ------------        ------------
<S>                                                                            <C>                 <C>                 <C>         
Contract revenue (includes amounts from related party)                         $      6,031        $     13,650        $     13,843

Costs and expenses:
        Research and development                                                     34,585              29,792              23,226
        General and administrative                                                    6,227               5,529               5,086
                                                                               ------------        ------------        ------------
        Total costs and expenses                                                     40,812              35,321              28,312
                                                                               ------------        ------------        ------------

Operating loss                                                                      (34,781)            (21,671)            (14,469)

Other income and expenses:
        Interest income                                                               2,786               2,481               1,988
        Interest expense                                                             (1,065)               (691)               (494)
        Gain on sale of investment in Selectide Corporation                            --                  --                 1,006
                                                                               ------------        ------------        ------------
        Other income, net                                                             1,721               1,790               2,500
                                                                               ------------        ------------        ------------
Net loss                                                                       $    (33,060)       $    (19,881)       $    (11,969)
                                                                               ============        ============        ============


Basic and diluted net loss per share                                           $      (2.47)       $      (1.81)       $      (1.32)
                                                                               ============        ============        ============

Shares used in computing basic and diluted net loss per share                    13,387,000          10,966,000           9,085,000
                                                                               ============        ============        ============


<FN>
                                                      See accompanying notes.
</FN>
</TABLE>

                                                                 F-4

<PAGE>


<TABLE>
                                                            SUGEN, Inc.

                                                 STATEMENT OF STOCKHOLDERS' EQUITY
                                                (In thousands, except share amounts)

<CAPTION>
                                                                                      Convertible
                                                                                    Preferred Stock              Common Stock
                                                                                    ----------------      --------------------------
                                                                                    Shares    Amount      Shares              Amount
                                                                                    ------    ------      ------              ------
<S>                                                                                  <C>      <C>        <C>            <C>        
Balances at December 31, 1994                                                        --       $--        8,161,700      $        82
Issuance of Common Stock upon exercise of stock options and in
        connection with an employee stock purchase plan                              --        --          141,824                1
Placement of Common Stock for cash, net of issuance costs of $450                    --        --        1,396,875               14
Issuance of Common Stock for cash to Zeneca Limited, net of
        issuance costs of $150                                                       --        --          789,141                8
Issuance of Common Stock for cash to ASTA Medica
        Aktiengesellschaft, net of issuance costs of $50                             --        --          431,137                4
Issuance of Common Stock for services                                                --        --           15,000             --   
Repurchase of Common Stock for cash from Selectide Corporation                       --        --         (300,760)              (3)
Amortization of deferred compensation                                                --        --             --               --   
Change in net unrealized losses on available-for-sale securities                     --        --             --               --   
Net loss                                                                             --        --             --               --   
                                                                              -----------     ----     -----------      -----------
Balances at December 31, 1995                                                        --        --       10,634,917              106
Issuance of Common Stock upon exercise of stock options and in
        connection with an employee stock purchase plan, net                         --        --          194,195                2
Issuance of Common Stock for cash and note in connection with
        the exercise of stock options                                                --        --          132,333                1
Issuance of Common Stock for cash to Allergan, net of issuance
        costs of $32                                                                 --        --          191,571                2
Issuance of Common Stock for cash in connection with the follow-on
        public offering, net of offering costs of $2,133                             --        --        2,070,000               21
Issuance of Common Stock upon exercise of warrants, net                                                      5,434             --   
Repurchase of Common Stock for cash from Amgen Inc.                                  --        --         (235,000)              (2)
Issuance of warrants for cash to Amgen Inc.                                          --        --             --               --   
Deferred compensation related to grant of certain stock options                      --        --             --               --   
Amortization of deferred compensation                                                --        --             --               --   
Change in net unrealized losses on available-for-sale securities                     --        --             --               --   
Net loss                                                                             --        --             --               --   
                                                                              -----------     ----     -----------      -----------
Balances at December 31, 1996                                                        --        --       12,993,450              130
Issuance of Common Stock upon exercise of stock options and in
        connection with an employee stock purchase plan, net                         --        --          288,696                3
Deferred compensation related to stock grant to an officer                                                  25,000             --   
Issuance of Common Stock for cash in connection with the follow-on
        public offering, net of offering costs of $2,340                             --        --        2,000,000               20
Fair value of warrants issued                                                        --        --             --               --   
Amortization of deferred compensation                                                --        --             --               --   
Change in net unrealized gains on available-for-sale securities                      --        --             --               --   
Net loss                                                                             --        --             --               --   
                                                                              -----------     ----     -----------      -----------
Balances at December 31, 1997                                                        --       $--       15,307,146      $       153
                                                                              ===========     ====     ===========      ===========



                                                                                                  Note                         
                                                                      Additional               Receivable                   Total 
                                                                       Paid-In     Deferred       From     Accumulated Stockholders'
                                                                       Capital   Compensation  Stockholder    Deficit       Equity
                                                                       -------   ------------  -----------    -------       ------
Balances at December 31, 1994                                         $  45,094    $    (587)   $    --      $ (26,270)   $  18,319
Issuance of Common Stock upon exercise of stock options and in
        connection with an employee stock purchase plan                     302         --           --           --            303
Placement of Common Stock for cash, net of issuance costs of $450        16,299         --           --           --         16,313
Issuance of Common Stock for cash to Zeneca Limited, net of
        issuance costs of $150                                           12,342         --           --           --         12,350
Issuance of Common Stock for cash to ASTA Medica
        Aktiengesellschaft, net of issuance costs of $50                  8,946         --           --           --          8,950
Issuance of Common Stock for services                                       139         --           --           --            139
Repurchase of Common Stock for cash from Selectide Corporation           (1,426)        --           --           --         (1,429)
Amortization of deferred compensation                                      --            190         --           --            190
Change in net unrealized losses on available-for-sale securities           --           --           --            275          275
Net loss                                                                   --           --           --        (11,969)     (11,969)
                                                                      ---------    ---------    ---------    ---------    ---------
Balances at December 31, 1995                                            81,696         (397)        --        (37,964)      43,441
Issuance of Common Stock upon exercise of stock options and in
        connection with an employee stock purchase plan, net                717         --           --           --            719
Issuance of Common Stock for cash and note in connection with
        the exercise of stock options                                       883         --           (883)        --              1
Issuance of Common Stock for cash to Allergan, net of issuance
        costs of $32                                                      3,966         --           --           --          3,968
Issuance of Common Stock for cash in connection with the follow-on
        public offering, net of offering costs of $2,133                 22,686         --           --           --         22,707
Issuance of Common Stock upon exercise of warrants, net                    --           --           --   
Repurchase of Common Stock for cash from Amgen Inc.                      (2,696)        --           --           --         (2,698)
Issuance of warrants for cash to Amgen Inc.                                 200         --           --           --            200
Deferred compensation related to grant of certain stock options             538         (538)        --           --           --   
Amortization of deferred compensation                                      --            225         --           --            225
Change in net unrealized losses on available-for-sale securities           --           --           --           (152)        (152)
Net loss                                                                   --           --           --        (19,881)     (19,881)
                                                                      ---------    ---------    ---------    ---------    ---------
Balances at December 31, 1996                                           107,990         (710)        (883)     (57,997)      48,530
Issuance of Common Stock upon exercise of stock options and in
        connection with an employee stock purchase plan, net              1,543         --           --           --          1,546
Deferred compensation related to stock grant to an officer                  350         (350)        --   
Issuance of Common Stock for cash in connection with the follow-on
        public offering, net of offering costs of $2,340                 29,640         --           --           --         29,660
Fair value of warrants issued                                             1,903         --           --           --          1,903
Amortization of deferred compensation                                      --            365         --           --            365
Change in net unrealized gains on available-for-sale securities            --           --           --             69           69
Net loss                                                                   --           --           --        (33,060)     (33,060)
                                                                      ---------    ---------    ---------    ---------    ---------
Balances at December 31, 1997                                         $ 141,426    $    (695)   $    (883)   $ (90,988)   $  49,013
                                                                      =========    =========    =========    =========    =========


<FN>
                                                      See accompanying notes.
</FN>
</TABLE>

                                                                 F-5


<PAGE>


<TABLE>
                                                            SUGEN, Inc.

                                                      STATEMENTS OF CASH FLOWS
                                          Increase (decrease) in cash and cash equivalents
                                                           (In thousands)

<S>                                                                                                                 <C>
                                                                                               Years Ended December 31,
                                                                                       --------------------------------------------
                                                                                         1997              1996               1995 
                                                                                       --------          --------          --------
<S>                                                                                    <C>               <C>               <C>      
Cash flows from operating activities
Net loss                                                                               $(33,060)         $(19,881)         $(11,969)
Adjustments to reconcile net loss to net cash used in
        operating activities:
        Depreciation and amortization                                                     3,146             2,308             1,629
        Deferred revenue                                                                    250            (6,183)            1,922
        Issuance of Common Stock for services                                              --                --                 139
        Gain on sale of investment in Selectide Corporation                                --                --              (1,006)
        Changes in operating assets and liabilities:
          Accounts receivable                                                                27                24                35
          Prepaid expenses and other current assets                                        (286)              278              (200)
          Other assets                                                                   (1,370)             (332)              (39)
          Accounts payable                                                                1,139               200              (420)
          Accrued liabilities                                                             2,861             3,819             1,996
                                                                                       --------          --------          --------
Net cash used in operating activities                                                   (27,293)          (19,767)           (7,913)
                                                                                       --------          --------          --------

Cash flows from investing activities
Purchases of short-term investments                                                     (54,884)          (27,998)          (57,118)
Maturities of short-term investments                                                     31,515            36,973            15,308
Sales of short-term investments                                                           3,441             4,418             6,873
Purchases of property and equipment, net                                                 (3,177)           (1,665)           (2,042)
Proceeds from sale of investment in Selectide Corporation                                  --                --               2,923
                                                                                       --------          --------          --------
Net cash provided by (used in) investing activities                                     (23,105)           11,728           (34,056)
                                                                                       --------          --------          --------

Cash flows from financing activities
Proceeds from issuance of Common Stock, net                                              31,206            27,395            37,916
Proceeds from issuance of senior custom convertible notes                                17,500              --                --
Repurchase of Common Stock                                                                 --              (2,698)           (1,429)
Proceeds from issuance of warrant                                                          --                 200              --
Proceeds from lease financing of property and equipment                                   2,750             1,247             2,109
Payments under capital lease obligations                                                 (2,094)           (1,479)           (1,000)
                                                                                       --------          --------          --------
Net cash provided by financing activities                                                49,362            24,665            37,596
                                                                                       --------          --------          --------

Net increase (decrease) in cash and cash equivalents                                     (1,036)           16,626            (4,373)
Cash and cash equivalents at beginning of year                                           24,852             8,226            12,599
                                                                                       --------          --------          --------
Cash and cash equivalents at end of year                                               $ 23,816          $ 24,852          $  8,226
                                                                                       ========          ========          ========

Supplemental disclosure of cash flow information
Cash paid during the year for interest                                                 $    847          $    691          $    494
                                                                                       ========          ========          ========

Supplemental schedule of noncash investing and
        financing activities:
Equipment acquired under capital leases                                                $   --            $   --            $  1,059
                                                                                       ========          ========          ========


<FN>
                                                       See accompanying notes
</FN>
</TABLE>

                                                                 F-6

<PAGE>


                                   SUGEN, Inc.

                          NOTES TO FINANCIAL STATEMENTS


1.   Organization and Significant Accounting Policies

Organization

         SUGEN,  Inc. (the "Company"),  a Delaware  corporation  founded in July
1991, is a  biopharmaceutical  company focusing on the discovery and development
of small  molecule  drugs which target  specific  cellular  signal  transduction
pathways.  Dysfunctional signal transduction  pathways have been shown to result
in a variety of chronic and acute  pathological  diseases,  including cancer and
diabetes as well dermatologic,  ophthalmic, neurologic and immune disorders. The
Company pursues its drug discovery  programs  independently and in collaboration
with other pharmaceutical companies.

Use of Estimates

         The  preparation  of  the  financial   statements  in  conformity  with
generally accepted  accounting  principles requires management to make estimates
and assumptions that affect the amounts reported in the financial statements and
accompanying notes. Actual results could differ from those estimates.

Cash, Cash Equivalents and Short-Term Investments

         The Company  considers  all highly liquid  investments  with a maturity
from date of purchase of three months or less to be cash equivalents.  All other
liquid investments are classified as short-term investments.  The Company limits
its  concentration  of risk by diversifying  its investments  among a variety of
industries and issuers.

         All  debt  securities  are  designated  as  available-for-sale  and are
carried  at fair  value,  with the  unrealized  gains  and  losses  reported  in
stockholders'  equity.  The  amortized  cost of debt  securities is adjusted for
amortization   of  premiums  and  accretion  of  discounts  to  maturity.   Such
amortization  is  included  in interest  income.  Realized  gains and losses and
declines  in  value  judged  to be  other-than-temporary  on  available-for-sale
securities are also included in interest income.  The cost of securities sold is
based  on  the  specific   identification  method.  Interest  and  dividends  on
securities are included in interest income. 

Revenue Recognition

         Revenue  from  collaborative  agreements  is  recorded  when  earned as
defined  under the terms of the  agreements.  Non-refundable  fees received upon
contract signing or terminations are recorded as deferred revenue and recognized
as income when the related start-up or wind-down activities are performed, which
is generally  over a twelve month period or less.  Non-refundable  up-front fees
received as consideration  for previous  research and development work performed
are  recognized in full upon contract  execution.  Milestones  are recorded when
earned.  In  instances  where  milestone  payments are received in the form of a
stock purchase at a premium above fair market value,  equity is recorded at fair
market value and the premium  recognized as revenue.  Periodic  research funding
payments  are  recognized  as  income  when  earned.  Substantially  all  of the
Company's revenue is derived from its collaborations.

Research and Development Expense

         Research and development  expense consists of independent  research and
development costs, the costs associated with work performed under collaborations
and the Company's  sponsored funding of research  projects  performed by others.
Research and  development  costs include  direct and  research-related  overhead
expenses and are expensed as incurred. 

Depreciation and Amortization

           Property and equipment are stated at cost and  depreciated  using the
straight-line  method over the estimated  useful lives of the assets,  which are
generally  three to five years.  Leasehold  improvements  are amortized over the
shorter of their estimated  useful lives or the term of the lease.  Amortization
of assets held under capital lease is included in depreciation expense.

                                       F-7

<PAGE>


Stock Based Compensation

         The Company generally grants stock options for a fixed number of shares
to employees with an exercise price equal to the fair value of the shares at the
date of grant.  The Company  accounts for stock option grants in accordance with
APB Opinion No. 25, Accounting for Stock Issued to Employees,  and, accordingly,
employs the intrinsic-value method to value stock option grants.

Net Loss Per Share

         In February  1997,  the  Financial  Accounting  Standards  Board issued
Statement of Financial  Accounting  Standards No. 128, Earnings Per Share ("SFAS
128").  SFAS 128 replaced the calculation of primary and fully diluted  earnings
per share with basic and diluted earnings per share. Unlike primary earnings per
share,  basic  earnings  per share  excludes  any  dilutive  effects of options,
warrants and convertible securities.  The adoption by the Company of SFAS 128 on
December  31,  1997 had no  impact  on the net loss per  share  for the  periods
reported.  Per share  amounts for all periods have been  presented in accordance
with SFAS 128 requirements.

            Net loss per share is computed using the weighted  average number of
common shares  outstanding.  Stock options,  convertible  preferred  stock,  and
warrants are excluded from the computation as their effect is antidilutive.

         If the Company had been in a net income position,  diluted earnings per
share would have been presented separately and would have included the effect of
outstanding  stock options and  warrants,  calculated  using the treasury  stock
method.

2.   Investments

<TABLE>
         The  following  is a summary  of  available-for-sale  securities  as of
December 31 (in thousands):

<CAPTION>
                                                                          Available-for-Sale Securities
                                               -------------------------------------------------------------------------------------
                                                               1997                                         1996
                                               --------------------------------------       ----------------------------------------

                                              Unrealized      Estimated                   Unrealized       Estimated
                                                Gains/          Fair                         Gains/          Fair
                                                 Cost         (Losses)        Value           Cost          (Losses)         Value
                                               --------       --------       --------       --------        --------        --------
<S>                                            <C>            <C>            <C>            <C>             <C>             <C>     
U.S. Treasury securities
   and obligations of U.S. 
   Government agencies                         $ 11,518       $     17       $ 11,535       $ 13,348        $    (21)       $ 13,327
U.S. corporate notes                             36,393             16         36,409         19,422              (8)         19,414
U.S. corporate
   commercial paper                              16,001              2         16,003          9,506              (2)          9,504
Certificates of deposit                           3,999              2          4,001           --              --              --
Repurchase agreements                               900           --              900          8,036            --             8,036
Market rate auction
preferred funds and other                         6,447           --            6,447          6,054              (1)          6,053
                                               --------       --------       --------       --------        --------        --------
                                               $ 75,258       $     37       $ 75,295       $ 56,366        $    (32)       $ 56,334
                                               ========       ========       ========       ========        ========        ========

Amounts included in:
   Cash equivalents                            $ 23,814       $      2       $ 23,816       $ 24,853        $     (1)       $ 24,852
   Short-term investments                        51,444             35         51,479         31,513             (31)         31,482
                                               --------       --------       --------       --------        --------        --------
                                               $ 75,258       $     37       $ 75,295       $ 56,366        $    (32)       $ 56,334
                                               ========       ========       ========       ========        ========        ========
</TABLE>


The  estimated  fair value  amounts have been  determined  by the Company  using
available market information and appropriate valuation  methodologies.  However,
the estimates presented herein are not necessarily indicative of the amounts the
Company could realize in a current market exchange.

As of December 31, 1997, the average portfolio  duration was approximately  five
months and the  longest  contractual  maturity  did not exceed two years.  Gross
realized gains and losses were immaterial during 1997 and 1996.

                                       F-8

<PAGE>


3.  Investment in Selectide Corporation

         In 1992, the Company signed a three-year  collaborative  agreement with
Selectide Corporation ("Selectide"), a privately-held corporation. In connection
with this  agreement,  the  Company  issued  300,760  shares of stock for junior
preferred shares of Selectide valued at $1.9 million,  which shares  represented
approximately 5% of the voting shares of Selectide as of December 31, 1994.

         In January 1995, the Company received  approximately  $2.9 million from
the sale of its 5% ownership in Selectide to Marion Merrell Dow, Inc., resulting
in a gain of approximately $1.0 million. The Company simultaneously  repurchased
the  300,760  shares  of SUGEN  Common  Stock  formerly  held by  Selectide  for
approximately $1.43 million, or $4.75 per share. The net proceeds to the Company
from these transactions was approximately $1.5 million.


4.   Property and Equipment

Property and equipment consists of the following at December 31 (in thousands):

                                                          1997           1996
                                                        --------       --------
Leasehold improvements                                  $  4,084       $  3,168
Office and computer equipment                              3,251          2,320
Laboratory equipment                                       4,226          2,896
                                                        --------       --------
                                                          11,561          8,384
Accumulated depreciation and amortization                 (6,960)        (4,289)
                                                        --------       --------
Net property and equipment                              $  4,601       $  4,095
                                                        ========       ========

         Property and equipment  under capital  leases  amounted to $8.9 million
and $7.5  million as of December  31, 1997 and 1996,  with  related  accumulated
amortization of $5.1 million and $3.9 million, respectively.


5.   Accrued Liabilities

The components of accrued  liabilities  consist of the following at December (in
thousands):

                                                            1997           1996
                                                           -------       -------
Accrued research and development services                  $ 5,351       $ 3,724
Accrued compensation                                         1,176           883
Accrued professional fees                                      859           524
Other                                                        2,881         2,275
                                                           -------       -------
                                                           $10,267       $ 7,406
                                                           =======       =======

6.   Research and Development Collaboration Agreements

Allergan, Inc.

         In October 1996,  the Company  established  a research and  development
collaboration with Vision Pharmaceuticals L.P., an affiliate of Allergan,  Inc.,
and  Allergan,  Inc.  (collectively,   "Allergan"),  to  identify,  develop  and
commercialize  novel  angiogenesis  inhibitors  for the  treatment of ophthalmic
diseases.  The  collaboration  will also  establish  a  comprehensive  effort to
identify and validate  signal  transduction  targets for  choroidal  and retinal
neovascularization.  Allergan will have exclusive  rights to all ophthalmic uses
of  collaboration  products  and  know-how  world-wide.  In return,  the Company
received a $2.0 million initial payment for past research services, is receiving
annual  research  funding  and  expects  to  receive  additional  fees  upon the
achievement  of specified  milestones  and  royalties on any product  sales.  In
addition,  the Company will have the right to contribute to clinical development
costs on each program,  thereby earning  participation in the North American and
European  profits from successful  products coming out of such programs over and
above its royalty  entitlement.  Allergan also purchased 191,571 shares of SUGEN
Common Stock at a price of $20.88 per share and  participated  in the  Company's
October

                                       F-9

<PAGE>


1996 financing (see Note 10),  purchasing an additional 250,000 shares of Common
Stock,  thereby  increasing  its cumulative  equity  investment in SUGEN to $7.0
million.

ASTA Medica Aktiengesellschaft

            In December  1995,  the  Company  established  an  oncology  product
development collaboration with ASTA Medica Aktiengesellschaft ("ASTA Medica") to
develop,  manufacture and bring to market SUGEN's  oncology  products based upon
the cell  signal  transduction  targets  known as Pan-Her  and Raf.  The Company
received  a  $4.0  million  technology  set-up  fee,  is  receiving   additional
consideration in the form of contract  services for  non-collaboration  work and
will receive certain milestone  payments tied to the success of the programs and
royalty  payments on sales in certain  territories.  In January 1998,  the first
milestone in connection  with the Company's  collaboration  with ASTA Medica was
achieved in the Pan-Her  cancer  program.  ASTA Medica  exercised  its option to
satisfy its $500,000 milestone  obligation through the purchase of 18,665 shares
of SUGEN  Common  Stock at a price of  $26.79 of which the  premium  above  fair
market value was recorded as revenue.  The agreement provides for ASTA Medica to
receive exclusive  marketing rights to collaboration  products in Greater Europe
(including the former Soviet Union) and South  America,  subject to royalties to
SUGEN.  The Company  retains market rights in the rest of the world,  subject to
royalties  payable to ASTA Medica in most  circumstances.  In addition,  in 1995
ASTA Medica purchased 431,137 shares of SUGEN Common Stock for $9.0 million,  or
$20.88 per share.

Zeneca Limited - Related Party

         In January 1995, the Company  established a  collaboration  with Zeneca
Limited ("Zeneca") to pursue the research,  development and commercialization of
novel  anti-cancer  drugs targeting  cell-surface  receptors and  intra-cellular
signal  transduction  pathways.  In connection with this agreement,  the Company
received an initial $5.0 million technology set-up fee, is receiving  additional
cash payments for annual  research  funding and will receive  certain  milestone
payments (which may be offset against  royalties over time) tied to the progress
of  compounds in the  collaboration  and  royalties  on  worldwide  sales of any
collaboration  products.  The Company will also have the right to  contribute to
clinical development costs on each program, thereby earning participation in the
North American profits from successful products coming out of such programs over
and above its royalty entitlement.

         As a part of the  collaboration  agreement,  Zeneca  purchased  789,141
shares of the  Company's  Common Stock for $12.5  million,  or $15.84 per share.
This $12.5  million  equity  investment,  combined  with  Zeneca's  $7.5 million
participation  in  SUGEN's  October  1994  initial  public  offering,  increased
Zeneca's  equity  investment  in SUGEN to $20.0  million  and  brought  Zeneca's
ownership in the Company to approximately 20%.

         Zeneca  participated in the Company's  November 1997,  October 1996 and
September  1995  financings  (see Note 10),  purchasing an  additional  456,000,
509,000 and 281,875 shares of the Company's  Common Stock,  respectively.  These
additional   investments   maintained  Zeneca's  ownership  level  in  SUGEN  at
approximately  20% and increased its cumulative equity investment in the Company
to $36.8  million.  Zeneca has committed not to increase its holdings above this
level without the approval of SUGEN's Board of Directors.

Amgen, Inc.

         In December  1992, the Company  established a research and  development
collaboration with Amgen Inc. ("Amgen") to discover and develop  therapeutic and
diagnostic  products in neurobiology and a subset of  hematopoiesis.  As part of
this collaboration, Amgen made a $4.0 million equity investment, which converted
into 387,878  shares of the Company's  Common Stock at the time of the Company's
initial public offering.  For the three year period ended December 31, 1995, the
Company received approximately $18.1 million of research funding from Amgen.

         In January 1996, the Company and Amgen reached an agreement to conclude
their research  collaboration  one year earlier than  originally  planned due to
their changed research priorities.  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
already  made to the  Company  for future  research  work which was  recorded as
wind-down revenue in 1996. Amgen also granted back to SUGEN exclusive  worldwide
rights to 22 propriety 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
redeemed  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
seven-year  warrant to purchase  200,000  shares of Common  Stock at an exercise
price of $15.50 per share.

                                      F-10

<PAGE>


7.   Leases

         In March 1997 and November  1997,  the Company  secured  capital  lease
lines for equipment and tenant  improvements  for $3.5 million and $5.0 million,
respectively.  At December  31, 1997,  the Company had a total of  approximately
$6.4 million available under these lease lines.

         The Company leases its current office and laboratory  facilities  under
operating  leases through 1998. Rent expense for the current facility leases and
other operating  leases amounted to $1.6 million,  $1.6 million and $1.4 million
for 1997, 1996 and 1995, respectively.  In June 1997, the Company entered into a
build-to-suit  facility  lease  agreement  which extends until 2015 with renewal
options of ten years. In connection with this agreement, the Company also issued
warrants  to purchase  shares of Common  Stock.  The  related  fair value of the
warrants was recorded as deferred  expenses and will be amortized  over the term
of the warrants.  Minimum rental amounts  stipulated in the lease are subject to
adjustment based upon the final square footage of the building and total cost at
completion.  Construction of the new facility is targeted for completion  during
the fourth quarter of 1998, which coincides with the expiration of the Company's
current facility leases.

         Future minimum  payments under capital and operating leases at December
31, 1997 are as follows (in thousands):

                                                     Capital        Operating
                                                     Leases           Leases
                                                    --------         --------
      Year ended December 31:
         1998                                       $  2,857         $  1,992
         1999                                          1,936            2,388
         2000                                          1,164            2,647
         2001                                            436            3,231
         2002                                             62            3,304
                                                    --------         
         Total minimum lease payments                  6,482         
                                                                     
         Amount representing interest                 (1,053)
                                                    --------
         Present value of minimum lease payments       5,429
         Less current portion                         (2,277)
                                                    --------
         Non-current portion                        $  3,152
                                                    ========


8.    Senior Custom Convertible Notes

          In September  1997,  the Company  completed  the sale of $17.5 million
principal amount of 5% Senior Custom  Convertible  Notes due 2000 (the "Notes").
The Notes were sold at par,  mature on September 12, 2000 and bear interest at a
rate of 5% per annum (payable in Common Stock or cash, at the Company's option).
The Notes are convertible  together with accrued and unpaid interest and subject
to certain limitations,  into shares of Common Stock at a conversion price equal
to the average of the two lowest  trade prices of the Common Stock during the 20
trading days  immediately  preceding  the date of  conversion  (the  "Conversion
Price").  Since January 19, 1998,  the  Conversion  Price may not exceed $14.87,
115% of the  average  closing  bid price of the Common  Stock for the 20 trading
days  immediately  preceding  such date. In connection  with the issuance of the
Notes,  the Company  issued  warrants to purchase up to 332,500 shares of Common
Stock at an exercise price of $16.74 per share. Cash and non-cash issuance costs
(including the fair value of the warrants)  totaled  approximately  $2.6 million
and are recorded as deferred  expenses  which are  amortized to expense over the
term of the Notes.  No purchaser  of the Notes will be allowed to convert  Notes
and/or  warrants  which would result in such person owning more than 4.9% of the
then outstanding Common Stock.

         Upon the occurrence of certain  events,  at the election of the holders
of the Notes,  the Company may be required to redeem in cash all or a portion of
the Notes at  redemption  prices which are at a premium to the face value of the
Notes.  If the Notes are not  converted  into  Common  Stock  upon  maturity  in
September  2000,  the Notes will be exchanged for 13.75%  five-year  debentures.
Pursuant to the terms of the Notes, in addition to other covenants,  the Company
has agreed to certain limitations on the incurrence of additional indebtedness.

                                      F-11

<PAGE>


9.  Commitments Under Research and Development Programs

         The  Company  enters  from  time  to time  into  license  and  research
agreements  whereby the Company funds research  projects  performed by others or
in-licenses compounds from third parties. Some of the agreements may require the
Company to make milestone and royalty payments.

         Under   these   programs,   commitments   for   research   funding  are
approximately $1.7 million, $1.6 million, $1.4 million and $1.1 million in 1998,
1999, 2000, and 2001,  respectively.  The Company  anticipates  renewing certain
contracts that expired in 1997 which will increase future  commitments.  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.  Related  research and development  expenses under
these programs were $3.1 million,  $3.5 million and $4.2 million for 1997,  1996
and 1995, respectively.

10.  Stockholders' Equity

Preferred Share Purchase Rights Plan

         In July  1995,  the  Board of  Directors  approved  a  Preferred  Share
Purchase  Rights  Plan  ("Rights  Plan").  The  Rights  Plan  provides  for  the
distribution of a preferred stock purchase right as a dividend for each share of
the Company's Common Stock.  This right entitles  stockholders to purchase stock
in the Company or in an acquirer  of the  Company at a  discounted  price in the
event of certain hostile  efforts to acquire control of the Company.  The rights
may only be  exercised,  if at all,  until the earlier of July 31, 2000,  or the
occurrence of certain  events,  and may be redeemed by the Company.  At December
31, 1997, the rights were not exercisable.

         In connection  with the Rights Plan,  300,000  shares of the authorized
Preferred Stock were designated as Series A Junior Participating Preferred Stock
("Junior  Preferred  Stock"),  of which one share is equivalent to 100 shares of
Common  Stock.  Each share of Junior  Preferred  Stock shall  entitle the holder
thereof to 100 votes on all matters  submitted to a vote of the stockholders and
shall rank,  with respect to the payment of dividends  and the  distribution  of
assets,  junior  to all  series of any other  class of the  Company's  Preferred
Stock.  Subject to the rights of the  holders of any shares of  Preferred  Stock
with respect to dividends,  the holders of shares of Junior  Preferred Stock, in
preference  to the  holders  of  Common  Stock,  shall be  entitled  to  receive
quarterly dividends,  when, as and if declared by the Board of Directors.  As of
December  31,  1997,   no  dividends  had  been  declared  and  no  shares  were
outstanding.

Common Stock

         In November 1997, the Company  completed a follow-on public offering of
2,000,000  shares  of  Common  Stock at a price of  $16.00  per  share.  The net
proceeds to the Company were approximately $29.7 million.

            In October and  November  1996,  the  Company  completed a follow-on
public  offering of  2,070,000  shares of Common  Stock at a price of $12.00 per
share. The net proceeds to the Company were approximately $22.7 million.

            In September  1995, the Company sold 1,396,875  shares of its Common
Stock at a price of $12.00 per share, resulting in net proceeds of approximately
$16.3 million.

          The total number of shares of Common Stock  outstanding was 15,307,146
as of December 31, 1997, of which 63,125 were subject to repurchase. At December
31, 1997, the Company has reserved 5,865,991 shares of Common Stock for issuance
upon  exercise of warrants and options and  conversion of debt and 85,543 common
shares for issuance under the Employee Stock Purchase Plan.

                                      F-12

<PAGE>


Warrants

         The following  warrants to purchase  shares of common stock were issued
in connection  with the Senior  Custom  Convertible  Notes and various  license,
facility and equipment lease financing arrangements (also see Notes 6, 7 and 8):

                          Warrants Outstanding at December 31, 1997
          ----------------------------------------------------------------------
                               Price Per
         Number of Shares        Share        Aggregate Price    Expiration Date
         ----------------      ---------      ---------------    ---------------
              332,500       $     16.74             $5,566,050   September 2000
              200,000             15.50              3,100,000   January 2003
               70,000             15.44              1,080,800   June 2002
               40,000              3.75                150,000   December 1999
               36,847             10.31                379,985   July 2000
               13,598             12.87                175,006   December 2001
                7,200             11.25                 81,000   December 1999
                2,666              4.69                 12,497   December 2001


Note Receivable from Stockholder

         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
continuous  status as an employee,  director or  consultant  with the Company is
terminated  for any reason  prior to the  payment in full 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.


11.  Stock Option and Purchase Plans

Employee Stock Purchase Plan

         In April 1994,  the Company  adopted an Employee  Stock  Purchase  Plan
("ESPP")  under which 200,000 shares of Common Stock were reserved for issuance.
All  employees  of the Company,  except  those having a 5% or greater  ownership
stake in the Company,  are eligible to  participate in the ESPP provided that on
the first day of an offering  period they have been  employed by the Company for
at least 30 days and are  customarily  employed by the  Company at least  twenty
hours per week and at least  five  months  per  calendar  year.  Offerings  will
generally  be for six  months,  with the  purchase  price per share equal to the
lower of 85% of the  market  value on the date  granted  (the  beginning  of the
offering  period) or on the date  purchased.  The next  offering  period ends on
March 31, 1998.  As of December 31, 1997,  114,457  shares had been issued under
the ESPP.

1992 Stock Option Plan

         The 1992  Stock  Option  Plan (the  "Plan")  provides  for the grant of
options to purchase  shares of Common Stock to  employees,  including  officers,
directors, and consultants, upon terms determined by the Board of Directors. The
options  granted  under  the Plan  may be  either  incentive  stock  options  or
nonstatutory  stock options.  As of December 31, 1997, an aggregate of 3,500,000
shares of Common Stock had been  reserved for issuance  under the Plan, of which
750,000 shares are subject to stockholders' approval.

         Options  granted under the Plan expire no later than ten years from the
date of grant.  The option price shall be at least 100% of the fair market value
on the date of grant for incentive stock options.  Nonstatutory  options, may be
granted as low as 85% of the fair market value on the date of grant. The options
generally become exercisable over a period of four years from the date of grant.
Options  may be  granted  with  different  vesting  terms  from  time to time as
approved  by the Board of  Directors.  The Plan has been  amended to provide for
automatic vesting of options granted upon a change of control, as defined.

         As of December 31, 1997,  options to purchase  851,649 shares of Common
Stock were  exercisable,  of which 117,813 shares would be subject to repurchase
if all were exercised.

                                      F-13

<PAGE>


         Through December 31, 1994, the Company recorded  deferred  compensation
expense for the difference  between the exercise price and the deemed fair value
for financial statement  presentation purposes of the Company's Common Stock for
certain  options granted in 1994 and 1993.  This deferred  compensation  expense
aggregated $757,000 and is being amortized over the related vesting period.

1994 Non-Employee Directors' Stock Option Plan

         In April 1994,  the Board of Directors  approved the 1994  Non-Employee
Directors'  Stock  Option  Plan  (the  "Directors'  Plan")  to  provide  for the
automatic grant of options to purchase shares of Common Stock to each person who
is elected as a director of the Company and who is not otherwise employed by the
Company (a "Non-Employee Director").

         Options  granted under this Plan to  Non-Employee  Directors upon their
initial  election to the Board will vest and be exercisable in five equal annual
installments  commencing  on the  date  one year  after  the date of the  grant.
Vesting is contingent upon the continuous service of the director.  The director
may elect at any time while a  Non-Employee  Director of the Company to exercise
the option  prior to vesting of the option.  Any  unvested  shares so  purchased
shall be subject to a repurchase  right in favor of the Company.  The Directors'
Plan has been amended to provide for automatic vesting of options granted upon a
change of control, as defined. Options granted annually to existing Non-Employee
Directors  vest in full on the  date ten  days  prior  to the date of the  first
annual  meeting of  stockholders  of the Company  subsequent  to the date of the
grant.  The exercise  price of options  granted under the  Directors'  Plan must
equal or exceed the fair market  value of the Common Stock on the date of grant.
Under this plan, 380,000 shares of Common Stock have been reserved for issuance,
of which 150,000 shares are subject to  stockholders'  approval.  As of December
31, 1997,  options for 161,000  shares were  outstanding,  of which  157,000 and
53,000  shares  were   exercisable  and  subject  to  repurchase  if  exercised,
respectively.

Long-Term Objectives Stock Option Plan for Senior Management

         In July 1995, the Board of Directors  adopted the Long-Term  Objectives
Stock Option Plan for Senior  Management (the "Long-Term  Plan").  The Long-Term
Plan  provides  for the grant of options to purchase  shares of Common  Stock to
certain  senior  employee  officers,  upon  terms  determined  by the  Board  of
Directors.  The options  granted under this Plan may be either  incentive  stock
options or nonstatutory stock options. Options granted under this Plan expire no
later than ten years from the date of grant.  The option price shall be at least
100% of the fair market value on the date of grant for incentive  stock options.
Under  this  plan,  270,000  shares of Common  Stock  have been  authorized  for
issuance.

         In August 1996, the Company  amended the terms of the then  outstanding
options on 180,000 shares of Common Stock to modify the vesting provisions.  The
amendment resulted in $538,000 of deferred compensation which is being amortized
over the remaining vesting period of approximately  five years. The options,  as
amended in August 1996, vest over a period of approximately six years.

         As of December 31, 1997,  options for 180,000 shares were  outstanding,
of which  144,000  shares and  101,250  shares were  exercisable  and subject to
repurchase if exercised, respectively.

Accounting for Stock Based Compensation

         The Company has elected to follow  Accounting  Principles Board Opinion
No. 25,  "Accounting  for Stock  Issued to  Employees"  ("APB  25") and  related
Interpretations  in  accounting  for its  employee  stock  options  because,  as
discussed below,  the alternative fair value accounting  provided for under FASB
Statement  No. 123,  "Accounting  for  Stock-Based  Compensation"  ("FAS  123"),
requires the use of option  valuation  models that were not developed for use in
valuing  employee  stock  options.  Under APB 25, when the exercise price of the
Company's  employee  stock  options  generally  equals the  market  price of the
underlying  stock on the date of grant,  generally  no  compensation  expense is
recognized.

         Pro forma  information  regarding  net income and earnings per share is
required by FAS 123,  which also requires that the  information be determined as
if the Company has accounted for its employee stock options  granted  subsequent
to December  31, 1994 under the fair value  method of that  Statement.  The fair
value  of  these   options  was  estimated  at  the  date  of  grant  using  the
Black-Scholes   option   pricing  model  with  the  following   weighted-average
assumptions for 1997, 1996 and 1995,  respectively:  risk-free interest rates of
5.9%, 5.9% and 5.7%;  dividend yields of 0%; volatility  factors of the expected
market  price  of the  Company's  Common  Stock  of  .55,  .57  and  .57;  and a
weighted-average expected life of the options of 3 years.

                                      F-14

<PAGE>


         The  Black-Scholes  option  valuation  model was  developed  for use in
estimating the fair value of traded  options which have no vesting  restrictions
and are fully  transferable.  In addition,  option  valuation models require the
input of highly  subjective  assumptions  including  the  expected  stock  price
volatility.  Because the Company's  employee stock options have  characteristics
significantly different that those of traded options, and because changes in the
subjective input assumptions can materially  affect the fair value estimate,  in
management's  opinion, the existing models do not necessarily provide a reliable
single measure of the fair value of its employee stock options.

         For purposes of pro forma disclosures,  the estimated fair value of the
options is amortized to expense over the options' vesting period.  The Company's
pro forma  information  follows (in  thousands,  except for  earnings  per share
information):

                                         1997           1996            1995
                                       ---------      ---------      ---------- 
Pro forma net loss                     $ (35,604)     $ (21,813)     $  (12,846)
                                       =========      =========      ==========
Pro forma net loss per share           $   (2.66)     $   (1.99)     $    (1.41)
                                       =========      =========      ==========


         The weighted  average fair value of options  granted during 1997,  1996
and 1995 was $5.66, $5.39 and $3.55, respectively. As FAS 123 is applicable only
to options  granted  subsequent to December 31, 1994,  its pro forma effects are
not fully reflected until 1997.

<TABLE>
         A summary of the Company's  stock option  activity  under the Company's
option plans which  include the 1992 Stock Option  Plan,  the 1994  Non-Employee
Directors'  Plan and the  Long-Term  Objectives  Stock  Option  Plan for  Senior
Management is as follows:

<CAPTION>
                                                           Outstanding Stock Options
                                                           --------------------------
                                      Shares Available                   Weighted
                                        For Grant of      Number of       Average
                                          Options          Shares     Price per Share
                                          -------          ------     ---------------
<S>                                    <C>              <C>              <C> 
    Balance at December 31, 1994          271,427          783,922        3.08
    Shares authorized                   1,300,000            --           --
    Options granted                    (1,131,137)       1,131,137        8.31
    Options exercised                       -             (112,261)       1.22
    Options forfeited                      16,370          (16,370)       5.11
                                          -------        ---------
    Balance at December 31, 1995          456,660        1,786,428        6.49
    Shares authorized                     650,000
    Options granted                      (652,066)         652,066       12.08
    Options exercised                       -             (305,072)       4.60
    Options forfeited                     235,559         (235,559)       7.85
                                          -------        ---------
    Balance at December 31, 1996          690,153        1,897,863        8.54
    Shares authorized                     900,000            --           --
    Options granted (a)                  (713,500)         713,500       13.15
    Options exercised                       -             (254,836)       5.13
    Options forfeited                      93,186          (93,186)      11.12
                                          -------        ---------
    Balance at December 31, 1997          969,839        2,263,341       10.27
                                          =======        ========= 
</TABLE>


         Note:
         (a)  Of the 713,500 options granted in 1997,  options for 77,161 shares
              are subject to stockholder approval.

                                      F-15

<PAGE>


<TABLE>
The following table  summarizes  information  concerning  currently  outstanding
options:

<CAPTION>
                                                                                       Exercisable
                                         Outstanding Stock Options                    Stock Options
                               ----------------------------------------------  ----------------------------
                                                  Weighted
                                                   Average        Weighted                     Weighted
                                                  Remaining        Average                      Average
            Range of               Number        Contractual      Exercise       Number        Price Per
            Exercise Prices       of Shares          Life           Price       of Shares        Share
            -----------------  --------------   --------------  -------------  ------------   -------------
<S>                                 <C>                 <C>           <C>         <C>               <C>  
            $0.38 - $2.44           163,493             5.6           $1.39       154,558           $1.34
             5.00 -  5.75            48,862             7.1            5.40        38,096            5.45
             6.00 -  8.13           498,821             7.2            7.12       419,662            7.21
             9.67 - 11.88           718,905             8.5           11.24       340,220           11.38
            12.00 - 14.88           819,878             9.5           13.27       199,843           13.21
            15.00 - 19.00            13,382             9.7           18.58           270           15.00
                               --------------                                  ------------
            $0.38 - $19.00        2,263,341             8.3          $10.27     1,152,649           $8.64
                               ==============                                  ============
</TABLE>


12.  Income Taxes

         As of  December  31,  1997,  the  Company  had  federal  and  state net
operating loss  carryforwards of  approximately  $88.3 million and $7.1 million,
respectively.   The  Company  also  had  federal  and  California  research  and
development  tax credit  carryforwards  of  approximately  $2.4 million and $1.7
million,  respectively.  The federal net operating loss and credit carryforwards
will expire at various  dates  beginning in the year 2006 through  2012,  if not
utilized.  The State of California  net operating  losses will expire at various
dates beginning in 1998 through 2002, if not utilized.

         Utilization  of the  Company's  net operating  loss  carryforwards  and
credits may be subject to an annual  limitation due to the "change in ownership"
provisions of the Internal  Revenue Code of 1986 and similar  state  provisions.
The annual  limiation may result in the  expiration of net operating  losses and
credits before utilization.

         Deferred income taxes reflect the net effects of temporary  differences
between the carrying amounts of assets for financial  reporting purposes and the
amount used for income tax  purposes.  Significant  components  of the Company's
deferred  tax assets for  federal  and state  income  taxes are as follows as of
December 31 (in thousands):

                                                           1997          1996
                                                         --------      --------
Net operating loss carryforwards                         $ 30,400      $ 19,300
Research credits carryforwards                              3,700         2,100
Capitalized R&D                                             1,700         1,100
Deferred revenue                                              100           200
Other - net                                                 1,900           800
                                                         --------      --------
Total deferred tax assets                                  37,800        23,500
Valuation allowance for deferred tax assets               (37,800)      (23,500)
                                                         --------      --------
Net deferred tax assets                                  $      0      $      0
                                                         ========      ========


         Due to the  Company's  history of losses,  the deferred tax assets have
been fully offset by a valuation allowance. The valuation allowance increased by
$8.0 million and $5.1  million for the fiscal years ended  December 31, 1996 and
1995, respectively.

         Deferred  tax assets as of  December  31,  1997  include  approximately
$900,000  relating to the exercise of stock  options,  which will be credited to
equity when realized.

13.  Related Party Transactions

         In  1992,  the  Company  entered  into a  collaboration  and  licensing
agreement  with  Selectide.  The  Chairman of the Board of  Directors  and Chief
Executive Officer of the Company was also the chairman of the Board of Directors
of Selectide (see Note 3).

                                      F-16

<PAGE>


         In 1996,  the  Company  made a  $100,000  investment  in a China  joint
venture.  The Chairman of the Board of Directors and Chief Executive  Officer of
the Company is also the Chairman and a director of the China joint venture.

         In 1995, the Company entered into a collaboration agreement with Zeneca
(see Note 6). As of December 31, 1997,  Zeneca  owned  approximately  20% of the
Company's outstanding Common Stock.

         In January  1996,  the Company  entered into a license  agreement  with
Zeneca for the  dermatological use of a synthetic small molecule  inhibitor.  In
connection  with the  Company's  filing of an  Investigational  New Drug ("IND")
application  with  the Food and Drug  Administration  ("FDA")  for the  clinical
testing of this compound, SU5271, the Company paid Zeneca $200,000.

         In  connection  with the  resignation  of an officer in June 1996,  the
Company  recorded  approximately  $500,000 in connection with the forgiveness of
loans and salary continuation.

         In August  1996,  an officer  and  director  of the  Company  exercised
options  to  purchase   132,333  shares  of  Common  Stock  (See  Note  10).  As
consideration  for the purchase of these shares and related tax  liability  upon
the exercise of the options,  the officer issued a full recourse promissory note
in the amount of $1.1 million to the Company, of which approximately $883,000 is
included in  stockholder's  equity.  In addition,  the Company  provided secured
loans to certain key  employees  and officers to assist in the down payments for
the purchase of their personal  residences,  all of which are  forgivable  after
specified  years of  employment.  Included  in Other  Assets  are  approximately
$271,000 of loans receivable from certain key employees and officers at December
31, 1997.  Further,  in September  1997,  the Company  granted  25,000 shares of
Common  Stock  to  an  officer  subject  to  forfeiture  and  recorded  deferred
compensation  expense in the amount of $350,000,  which is being  amortized over
the vesting period of the shares.

                                      F-17

<PAGE>


                                   SIGNATURES

         Pursuant to the  requirements  of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized, in the City of Redwood
City, State of California, on March 26, 1998.


                                                SUGEN, INC.


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



                                POWER OF ATTORNEY

         KNOW ALL PERSONS BY THESE  PRESENTS,  that each person whose  signature
appears below constitutes and appoints Stephen  Evans-Freke and Susan M. Kanaya,
and each of them, his true and lawful  attorneys-in-fact  and agents,  with full
power of substitution and  resubstitution,  for him and in his name,  place, and
stead, in any and all capacities, to sign any and all amendments to this report,
and to file  the  same,  with all  exhibits  thereto,  and  other  documents  in
connection therewith, with the Securities and Exchange Commission, granting unto
said attorneys-in-fact and agents, and each of them, full power and authority to
do and perform each and every act and thing  requisite  and necessary to be done
in  connection  therewith,  as fully to all intents and  purposes as he might or
could  do  in  person,   hereby   ratifying   and   confirming   all  that  said
attorneys-in-fact and agents, or his substitutes or substitute,  may lawfully do
or cause to be done by virtue hereof.

<TABLE>
         Pursuant to the requirements of the Securities Act of 1934, this report
has been  signed by the  following  persons on behalf of the  Registrant  in the
capacities and on the dates indicated.

<CAPTION>
       Signature                                  Title                                    Date
       ---------                                  -----                                    ----
<S>                                    <C>                                              <C>
/s/ Stephen Evans-Freke                Chief Executive Officer and                      March 26, 1998
- --------------------------------       Chairman of the Board
(Stephen Evans-Freke)                  (Principal Executive and Financial
                                       Officer)



/s/ Susan M. Kanaya                    Treasurer                                        March 26, 1998
- --------------------------------       (Principal Accounting Officer)
(Susan M. Kanaya)                      


<PAGE>


/s/ Axel Ullrich                       Director                                         March  26, 1998
- --------------------------------
(Axel Ullrich)



/s/ Richard D. Spizzirri               Director and Secretary                           March 26, 1998
- --------------------------------
(Richard D. Spizzirri)



/s/ Jeremy L. Curnock Cook             Director                                         March 26, 1998
- --------------------------------
(Jeremy L. Curnock Cook)



/s/ Charles M. Hartman                 Director                                         March 26, 1998
- --------------------------------
(Charles M. Hartman)



/s/ Heinrich Kuhn                      Director                                         March 26, 1998
- --------------------------------
(Heinrich Kuhn)



/s/ Donald E. Nickelson                Director                                         March 26, 1998
- --------------------------------
(Donald E. Nickelson)



/s/ Bruce R. Ross                      Director                                         March 26, 1998
- --------------------------------
(Bruce R. Ross)



/s/ Michael A. Wall                    Director                                         March 26, 1998
- --------------------------------
(Michael A. Wall)
</TABLE>




                                            ***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").

                                       1

<PAGE>


         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.


- ----------------------------------
* Confidential Treatment Requested

                                        2

<PAGE>


         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

- ----------------------------------
* Confidential Treatment Requested

                                       3

<PAGE>

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

- ----------------------------------
* Confidential Treatment Requested

                                       4

<PAGE>


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

- ----------------------------------
* Confidential Treatment Requested

                                       5

<PAGE>


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.

                                       6

<PAGE>


         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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                                       7

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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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* Confidential Treatment Requested

                                       8

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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

                                       9

<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.

                                       10

<PAGE>


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

<PAGE>


         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

                                       12

<PAGE>


                                    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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* Confidential Treatment Requested


<PAGE>


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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* Confidential Treatment Requested

                                       2

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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.


- ----------------------------------
* Confidential Treatment Requested

                                       3

<PAGE>


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.


- ----------------------------------
* Confidential Treatment Requested

                                       5

<PAGE>


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


- ----------------------------------
* Confidential Treatment Requested
s

<PAGE>


                                    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.


- ----------------------------------
* Confidential Treatment Requested



<PAGE>


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


- ----------------------------------
* Confidential Treatment Requested

                                       2

<PAGE>


                                    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


- ----------------------------------
* Confidential Treatment Requested

                                       3

<PAGE>


                                    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


- ----------------------------------
* Confidential Treatment Requested

                                       4

<PAGE>


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


- ----------------------------------
* Confidential Treatment Requested

                                       5




                        RESTRICTED STOCK BONUS AGREEMENT
                           WITH K. PETER HIRTH, PH.D.

     THIS  AGREEMENT  is made as of the  16th  day of  September,  1997,  by and
between SUGEN, INC., a Delaware corporation (the "Company"), and K. Peter Hirth,
Ph.D. ("Recipient").


                                  WITNESSETH:

     WHEREAS, Recipient has provided valuable services to the Company;

     WHEREAS,  the Company desires to issue,  and Recipient  desires to receive,
shares of the Company's common stock ("Common Stock") in consideration  for past
services rendered to the Company or for its benefit; and

     WHEREAS,  the issuance of Common stock  hereunder is in connection with and
in furtherance of the Company's  compensatory  benefit program for participation
of the Company's employees, directors, officers, consultants and advisors.

     NOW, THEREFORE, IT IS AGREED between the parties as follows:

     1. The Company  hereby awards to Recipient  twenty-five  thousand  (25,000)
shares of Common  Stock  (the  "Shares"),  subject  to the  following  terms and
conditions.

     2.  Provided  that  Recipient  has  continuously  rendered  services to the
Company  or any  affiliate  of the  Company  from  and  after  the  date of this
Agreement  through  March 31, 1999,  the Shares shall vest in their  entirety on
March 31, 1999 (the  "Vesting  Date").  However,  to the extent the Vesting Date
occurs on a date on which the trading of the Shares  either (i) would  result in
liability  to Recipient  under Rule 10b-5 as  promulgated  under the  Securities
Exchange  Act of 1934,  as  amended,  or (ii)  would  be  prohibited  under  the
Company's  trading window policy  designed to prevent  violations of Rule 10b-5,
then the Vesting Date shall be delayed  until the first date on which  Recipient
could trade the Shares without either  incurring  liability  under Rule 10b-5 or
violating the Company's insider trading window policy.

     3. If at any time prior to the  Vesting  Date,  Recipient  ceases to render
services to the Company or any affiliate of the Company (the "Separation"),  the
Shares shall immediately cease vesting, Recipient shall have no further right in
the Shares and the Shares shall  automatically  be  reacquired by the Company at
the Current Market Price (as hereinafter  defined).  The Current Market Price of
the Company's  Common Stock shall be the closing price (or bid price if there is
no  such  closing   price)  of  the   Company's   Common  Stock  quoted  in  the
Over-The-Counter Market  Summary  or the  closing  price  quoted  on the  Nasdaq
National  Market or on the  primary  national  securities  exchange on which the
Common  Stock is then  listed,  whichever  is  applicable,  as  published in the
Western Edition of The Wall Street Journal (or, if not so reported, as otherwise
reported by the Nasdaq National  Market) on the date of Recipient's  Separation;
provided, however, that if there is no public market for the Company's Common



<PAGE>


Stock,  the Current Market Price shall be the fair market value of the Company's
Common Stock as determined by the Company's Board of Directors in good faith.

     4.  Recipient  may  satisfy  any  federal,  state or local tax  withholding
obligation  relating to the  acquisition  of the Shares by any of the  following
means or by a  combination  of such means:  (1)  tendering a cash  payment,  (2)
authorizing the Company to withhold shares from the Shares otherwise issuable to
Recipient as a result of the acquisition of the Shares, or (3) delivering to the
Company owned and unencumbered shares of the Common Stock of the Company.

     5.  Recipient  acknowledges  that the Shares to be issued  pursuant to this
Agreement have not been registered  under the Securities Act of 1933, as amended
(the "Securities Act"), and that the Shares are deemed to constitute "restricted
securities"  under  Rule 144  promulgated  under  the  Securities  Act.  In this
connection,  Recipient  warrants and represents to the Company that Recipient is
holding the Shares for Recipient's own account and that Recipient has no present
intention of  distributing  or selling said stock except as permitted  under the
Securities  Act.  Recipient  further  warrants and represents that Recipient has
either (i) a preexisting  personal or business  relationship with the Company or
any of its officers,  directors or controlling  persons, or (ii) the capacity to
protect his or her own interests in connection with the receipt of the Shares by
virtue of the business or financial  expertise of any  professional  advisors to
Recipient who are unaffiliated with, and who are not compensated by, the Company
or any of its affiliates, directly or indirectly. Recipient further acknowledges
that the exemption from registration under Rule 144 will not be available for at
least two (2) years from the date of acquisition of the Shares,  unless at least
one (1) year  from the date of  acquisition  (i) a public  trading  market  then
exists for the Common Stock of the Company, (ii) adequate information concerning
the Company is then available to the public and (iii) other terms and conditions
of Rule 144 are complied  with;  and that any  disposition  of the Shares may be
made only in limited amounts in accordance with such terms and conditions.

     6. Until the Vesting Date, the Shares shall be issued in book form only and
share certificates shall not be issued.  Notwithstanding  the foregoing,  in the
event  that   certificates   representing  the  Shares  are  issued,   all  such
certificates shall have endorsed thereon the following legends:

         (a) "THE  SECURITIES  REPRESENTED BY THIS  CERTIFICATE ARE UNVESTED AND
     SUBJECT  TO  FORFEITURE  IN  ACCORDANCE  WITH THE  RESTRICTED  STOCK  BONUS
     AGREEMENT BETWEEN THE ISSUER AND THE REGISTERED  HOLDER, OR THE PREDECESSOR
     IN INTEREST,  A COPY OF WHICH IS ON FILE AT THE ISSUER'S  PRINCIPAL OFFICE.
     ANY  TRANSFER  OR  ATTEMPTED  TRANSFER  OF THE SHARES  REPRESENTED  BY THIS
     CERTIFICATE  IS VOID  WITHOUT  THE PRIOR  EXPRESS  WRITTEN  CONSENT  OF THE
     ISSUER."

         (b)  "THE  SECURITIES  REPRESENTED  BY THIS  CERTIFICATE  HAVE NOT BEEN
     REGISTERED  UNDER  THE SECURITIES ACT OF 1933, AS AMENDED (THE  "SECURITIES
     ACT"). THEY MAY NOT BE SOLD OR



<PAGE>


     OFFERED  FOR  SALE OR  OTHERWISE  DISTRIBUTED  UNLESS  THE  SECURITIES  ARE
     REGISTERED   UNDER  THE  SECURITIES  ACT  OR  AN  EXEMPTION   THEREFROM  IS
     AVAILABLE."

     7. Recipient  agrees that it shall in no event make any  disposition of all
or any portion of the Shares unless and until:

         (i)  There  is  then in  effect  a  registration  statement  under  the
Securities Act covering such proposed  disposition and such  disposition is made
in accordance with said registration statement; or

         (ii) (a)  Recipient  shall have  notified  the Company of the  proposed
disposition  and shall have  furnished the Company with a derailed  statement of
the circumstances surrounding the proposed disposition, (b) Recipient shall have
furnished the Company with an opinion of its own counsel to the effect that such
disposition  will not require  registration  of the Shares under the  Securities
Act, and (c) such opinion of its counsel shall have been concurred in by counsel
for the Company,  such  concurrence  not to be  unreasonably  withheld,  and the
Company shall have advised Recipient of such concurrence.

     8. The  Company  shall not be  required  (i) to  transfer  on its books any
Shares  which shall have been sold or  transferred  in  violation  of any of the
provisions set forth in this  Agreement or the terms of the  Securities  Act, or
(ii) to treat as owner of such  Shares  or to  accord  the right to vote as such
owner or to pay dividends to any  transferee to whom such Shares shall have been
so transferred.

     9. Subject to the provisions of this Agreement, Recipient shall, during the
term of this  Agreement,  exercise all rights and privileges of a stockholder of
the  Company  with  respect to the Shares.  Recipient  shall be deemed to be the
holder of the Shares for purposes of receiving any  dividends  which may be paid
with respect to such Shares and for  purposes of  exercising  any voting  rights
relating to such Shares,  even if some or all of such Shares have not yet vested
and been released from the Company's reacquisition right.

     10. If any change is made in the Shares subject to this Agreement  (through
merger,  consolidation,   reorganization,   recapitalization,   stock  dividend,
dividend  in  property  other  than cash,  stock  split,  liquidating  dividend,
combination  of shares,  exchange of shares,  change in  corporate  structure or
otherwise),  this Agreement will be  appropriately  adjusted in the class(es) of
securities,  maximum  number of Shares  and  price  per  Share  subject  to this
Agreement.

     11. In the event of: (1) a merger or  consolidation in which the Company is
not the surviving corporation;  (2) a reverse merger in which the Company is the
surviving  corporation but the shares of the Company's Common Stock  outstanding
immediately  preceding  the merger are  converted  by virtue of the merger  into
other property,  whether in the form of securities,  cash or otherwise;  (3) any
other  capital  reorganization  in which  more than fifty  percent  (50%) of the
shares of the Company entitled to vote are exchanged; (4) a transaction or group
of related  transactions  involving the sale of all or substantially  all of the
Company's assets; (5) the acquisition by any person,  entity or group (excluding
any employee benefit plan, or related trust,



<PAGE>


sponsored or maintained by the Company or any  subsidiary of the Company) of the
beneficial  ownership,  directly or  indirectly,  of  securities  of the Company
representing  more than fifty percent (50%) of the combined  voting power in the
election of members of the board of directors of the Company; or (6) a change in
the composition of the Company's Board of Directors such that, during any period
of two  consecutive  years,  individuals  who, at the  beginning of such period,
constitute the Board of Directors,  together with  individuals  who are Approved
New Directors (as defined below), cease for any reason to have authority to cast
at least a majority of the votes which all  directors  on the Board are entitled
to vote;  then, to the extent not prohibited by law, the time during the Vesting
Date shall be accelerated  prior to such event.  For purposes of this Agreement,
an  "Approved  New  Director"  shall be a Board member  whose  election,  or the
nomination for election by the Company's stockholders, was approved by a vote of
a  majority  of the votes  entitled  to be cast by the  directors  then still in
office who were directors at the beginning of the period.

     12.  The  acquisition  and  vesting  of the  Shares  may have  adverse  tax
consequences  to the  Recipient  which may  avoided  or  mitigated  by filing an
election  under  Section  83(b) of the Internal  Revenue  Code,  as amended (the
"Code").  Such  election must be filed within thirty (30) days after the date of
this Agreement.  RECIPIENT  ACKNOWLEDGES THAT IT IS HIS OWN RESPONSIBILITY,  AND
NOT THE COMPANY'S,  TO FILE A TIMELY ELECTION UNDER CODE SECTION 83(B),  EVEN IF
RECIPIENT REQUESTS THE COMPANY TO MAKE THE FILING ON HIS OR HER BEHALF.

     13. Rights and  obligations  under this Agreement  shall not be impaired by
any amendment of this Agreement  unless (i) the Company  requests the consent of
Recipient and (ii) Recipient consents in writing.

     14. The parties  hereto agree to execute such  further  instruments  and to
take such further  action as may reasonably be necessary to carry out the intent
of this Agreement.

     15. Any notice  required or permitted  hereunder  shall be given in writing
and shall be deemed  effectively given upon personal delivery or upon deposit in
the United States Post Office,  by registered or certified mail with postage and
fees  prepaid,  addressed to the other party  hereto at its address  hereinafter
shown below its  signature or at such other  address as such party may designate
by ten (10) days' advance written notice to the other party hereto.

     16. This Agreement shall be governed by the laws of the State of California
without regard to such State's principles of conflict of laws.

     17. This Agreement shall inure to the benefit of the successors and assigns
of the Company and,  subject to the  restrictions  on transfer herein set forth,
shall be binding upon Recipient,  his or her heirs,  executors,  administrators,
successors and assigns.

     18. This Agreement does not constitute an employment  contract nor shall be
deemed to create in any way whatsoever  any  obligation on  Recipient's  part to
continue in the employ of the Company or any  affiliate  of the  Company,  or to
limit the ability of the Company or any



<PAGE>


affiliate of the Company to terminate  Recipient's  employment  with the Company
or affiliate of the Company at any time, for any reason or for no reason.

     19. This Agreement constitutes the entire, final and exclusive statement of
the  agreement  between the parties  hereto with  respect to the subject  matter
hereof.

     IN WITNESS  WHEREOF,  the parties hereto have executed this Agreement as of
the date first above written.


RECIPIENT:                                        SUGEN, INC.:

/s/ K. Peter Hirth Ph.D                           By /s/ Stephen Evans-Freke
- ---------------------------                          ---------------------------
K. Peter Hirth Ph.D                                  Stephen Evans-Freke
                                                     Chief Executive Officer and
Address: ------------------                          Chairman of the Board of
                                                     Directors
- ---------------------------




               CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS




We consent to the incorporation by reference in the Registration Statement (Form
S-8 No.  333-30385),  dated June 30, 1997,  pertaining  to the SUGEN,  Inc. 1992
Stock Option Plan, and in the Registration  Statement (Form S-3 No.  333-37687),
dated  October 10, 1997  pertaining to the  registration  statement of 1,780,000
shares of common stock, of our report dated February 5, 1998 with respect to the
financial  statements of SUGEN,  Inc. included in this Annual Report (Form 10-K)
for the year ended December 31, 1997.


                                                             ERNST & YOUNG LLP


Palo Alto, California
March 30, 1998



<TABLE> <S> <C>


<ARTICLE>                     5
<LEGEND>
     THE SCHEDULE  CONTAINS  SUMMARY  FINANCIAL  INFORMATION  EXTRACTED FROM THE
     COMPANY'S  10-K FOR THE YEAR ENDED DECEMBER 31, 1997 AND IN ITS ENTIRETY BY
     REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER>                                   1,000
       
<S>                             <C>
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                              DEC-31-1997
<PERIOD-START>                                 JAN-01-1997
<PERIOD-END>                                   DEC-31-1997
<CASH>                                         23,816
<SECURITIES>                                   51,479
<RECEIVABLES>                                       0
<ALLOWANCES>                                        0
<INVENTORY>                                         0
<CURRENT-ASSETS>                               76,286
<PP&E>                                         11,561
<DEPRECIATION>                                 (6,960)
<TOTAL-ASSETS>                                 84,825
<CURRENT-LIABILITIES>                          15,160
<BONDS>                                        20,652
                               0
                                         0
<COMMON>                                          153
<OTHER-SE>                                     48,860
<TOTAL-LIABILITY-AND-EQUITY>                   84,825
<SALES>                                             0
<TOTAL-REVENUES>                                6,031
<CGS>                                               0
<TOTAL-COSTS>                                       0
<OTHER-EXPENSES>                               34,585
<LOSS-PROVISION>                                    0
<INTEREST-EXPENSE>                              1,065
<INCOME-PRETAX>                               (33,060)
<INCOME-TAX>                                        0
<INCOME-CONTINUING>                           (33,060)
<DISCONTINUED>                                      0
<EXTRAORDINARY>                                     0
<CHANGES>                                           0
<NET-INCOME>                                  (33,060)
<EPS-PRIMARY>                                   (2.47)
<EPS-DILUTED>                                   (2.47)
        


</TABLE>


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