EXHIBIT 10.41
          PORTIONS OF THIS DOCUMENT HAVE BEEN OMITTED (DESIGNATED BY AN
           ASTERISK (*) AND WHITE SPACE) AND FILED SEPARATELY WITH THE
          SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR
                             CONFIDENTIAL TREATMENT
                    DATED January 14, 1998; FILE NO. 0-15609



                    AMENDMENT TO AGOURON-ROCHE COLLABORATION


         This Amendment to the Agouron-Roche Collaboration,  dated for reference
purposes   only  this  1st  day  of   December,   1997,   is   between   Agouron
Pharmaceuticals,  Inc., a corporation duly organized and existing under the laws
of the State of California,  having a principal place of business at 10350 North
Torrey Pines Road, La Jolla,  California,  United States of America (hereinafter
referred to as "Agouron,"  the first  party),  and F.  Hoffmann-La  Roche Ltd, a
corporation duly organized and existing under the laws of Switzerland,  having a
principal place of business at CH-4070-Basel, Switzerland, and Hoffmann-La Roche
Inc., a corporation  duly  organized and existing under the laws of the State of
New Jersey,  having a  principal  place of  business  at 340  Kingsland  Street,
Nutley, New Jersey, United States of America (hereinafter  collectively referred
to as "Roche," the second  party).  Agouron and Roche are sometimes  hereinafter
each referred to as a party (collectively  "parties").  The parties hereby agree
as follows:

                             ARTICLE I - BACKGROUND

         1.01 Defined terms used herein and not expressly  defined (i.e.,  terms
with  initial  capitalization)  shall  have  the  meanings  given to them in the
applicable agreements referred to below.

         1.02 On June 19,  1996,  Agouron  and  Roche  entered  into a Letter of
Intent ("LOI") to confirm the parties'  formation of a collaboration  (sometimes
referred to herein as the  "Collaboration") on terms substantially in accordance
with those  contained in Exhibit A to the LOI ("Exhibit  A"). The  components of
such Collaboration include programs for the development and commercialization of
the chemical  compounds known as THYMITAQ(TM)  (sometimes  referred to herein as
AG337) and AG3340 and in certain circumstances  substituted or additional backup
compounds, the Cell Cycle Control Research Program, and in certain circumstances
Agouron's  right to  commercialize  a Roche  Cancer  Product.  While  Exhibit  A
contains the basic terms of the understanding  between the parties,  the parties
agreed  that  the  terms  of the  Collaboration  would  be  subject  to  further
negotiation and preparation of further agreements that contain the full terms of
the Collaboration between the parties.

         1.03  On  June  11,  1997,  the  parties   entered  into  the  THYMITAQ
Development  and  License  Agreement  and the  AG3340  Development  and  License
Agreement,  which set  forth the full  terms of the  Collaboration  between  the
parties with  respect to the AG337 and AG3340  chemical  compounds  (and certain
substituted or additional backup compounds).

         1.04 The parties  have not entered into  further  agreements  which set
forth the definitive terms under which the parties shall collaborate in the Cell
Cycle  Control  Research  Program or Agouron's  right to  commercialize  a Roche
Cancer Product.


         1.05 Pursuant to the terms of the LOI and the THYMITAQ  Development and
License  Agreement  ("THYMITAQ  Agreement"),  the  parties  are  conducting  the
THYMITAQ Development Program.

         1.06  Pursuant to the terms of the LOI and the AG3340  Development  and
License Agreement  ("AG3340  Agreement"),  the parties are conducting the AG3340
Development Program and a Backup MMP Inhibitor Research Program.

         1.07 Pursuant to the terms of the LOI,  the parties are  conducting the
Cell Cycle  Control  Research Program.

         1.08 The LOI and Sections  2.04 and 6.02(a) of the  THYMITAQ  Agreement
and Sections 2.04 and 6.02(a) of the AG3340 Agreement permit Roche to cancel the
development programs being conducted pursuant to such agreements.

         1.09 Roche has informed  Agouron that it has undertaken a review of its
internal and external research and development  programs,  and has determined to
refocus  certain  of its  research  and  development  efforts.  As  part of such
refocusing  efforts,  Roche has decided to  terminate  the  THYMITAQ  and AG3340
Development  Programs  and its  rights  to elect to  develop  and  commercialize
substituted  or  additional  backup  compounds.  Additionally,  the parties have
decided to terminate the Cell Cycle Control Research Program and Agouron's right
to commercialize a Roche Cancer Product.

         1.10 To effect  the  preceding  and  clarify  the  parties'  rights and
obligations under the Collaboration, the parties wish to amend the Collaboration
as noted below.

                                           ARTICLE II - AMENDMENT

         2.01  Roche  hereby   irrevocably  elects  to  terminate  the  THYMITAQ
Development  Program  effective  December 8, 1997 pursuant to the  provisions of
Sections 2.04 and 6.02(a) of the THYMITAQ Agreement.  Effective December 1, 1997
Roche hereby irrevocably releases and terminates its rights under the provisions
of Sections  2.01(l) and (m) and 2.02 of the  THYMITAQ  Agreement to develop and
commercialize  AG337,  the free base form of AG337 and/or  another salt thereof.
Roche  further  elects to  terminate  its rights  under the  THYMITAQ  Trademark
License including its right to use the THYMITAQ Trademark.

         2.02  Roche  hereby   irrevocably   elects  to  terminate   the  AG3340
Development  Program  effective  May 20,  1998  pursuant  to the  provisions  of
Sections 2.04 and 6.02(a) of the AG3340 Agreement.  Effective  December 1, 1997,
Roche hereby irrevocably releases and terminates its rights under the provisions
of  Sections  2.01(l)  and (m) and 2.02 of the AG3340  Agreement  to develop and
commercialize AG3340 and Backup MMP Inhibitors including the compounds listed on
Schedule 2 to the AG3340 Agreement.

                                       2




         2.03  Roche  shall  continue  to be  obligated  for  its  share  of the
Development  Costs for the  THYMITAQ  Development  Program  until the  effective
termination  date of the  THYMITAQ  Development  Program  (December 8, 1997) and
shall fund and  reimburse  such  obligation  as described in Attachment 1 of the
applicable agreement. The parties further agree that no further license issuance
fees  payments  (other than the initial  US$5  million fee) shall be due Agouron
pursuant to the provisions of Section 5.01(a) of the THYMITAQ Agreement.

         2.04     Roche shall pay Agouron on or before December 15, 1997 *
                                                       in full  satisfaction and
settlement  of its share of the  Development  Costs for the  AG3340  Development
Program for the period from October 1, 1997 until the effective termination date
of the AG3340 Development Program (May 20, 1998); provided,  however, that Roche
shall be  entitled to receive a credit  against the amount due Agouron  equal to
Roche's  pre-payment of AG3340  Development  Program  Development  Costs for the
calendar  quarter ending December 31, 1997.  Agouron shall have no obligation to
account to Roche for any  Development  Costs  which  Agouron  incurs on or after
October  1, 1997 and shall be  entitled  to retain  and use such * payment  from
Roche for any  purposes  it sees fit,  including  uses  unrelated  to the AG3340
Development  Program.  Agouron shall reimburse  Roche for any Development  Costs
which  Roche  incurs  after  October  1, 1997 in  performing  development  tasks
assigned to it by Agouron or agreed to by the parties including, but not limited
to,  Development Costs incurred by Roche in performing the activities  described
in Paragraphs 2.16,  2.17, 2.18 and 2.19 of this Amendment;  Roche shall invoice
Agouron for such Development  Costs in accordance with the provisions  described
in  Attachment  1 of the AG3340  Agreement.  The parties  further  agree that no
further  license  issuance fees  payments  (other than the initial US$10 million
fee) shall be due Agouron  pursuant to the provisions of Section  5.01(a) of the
AG3340 Agreement.

         2.05 Roche agrees to cooperate with and provide  reasonable  assistance
to  Agouron  to  effect  an  orderly  transition  of  Roche's   development  and
Registration  responsibilities  for the THYMITAQ and AG3340 Development Programs
to Agouron.  Agouron shall lead implementation of the AG3340 Development Program
during such transition. The parties will use reasonable efforts to transition to
Agouron by December 31, 1997 Roche's clinical, regulatory and project management
responsibilities  for the  AG3340  Development  Program.  The  parties  will use
reasonable efforts to complete  substantially all of the transition on or before
the effective  termination date of the applicable  development  programs. To the
extent that Roche's  reasonable  costs of conducting the  transition  activities
assigned to it by Agouron do not otherwise  qualify as Development  Costs,  such
transition costs shall nevertheless be deemed to be Development Costs if Agouron
pre-approves  of a budget for each of  Roche's  requested  transition  activites
detailing  the  basis of the  calculation  of such  costs  for  each  transition
activity  and the  maximun  amount  of costs  which  Roche  may  incur  for each
transition  activity;  Roche shall be reimbursed for such pre-approved  budgeted
transition costs in accordance with the provisions  described in Attachment 1 of
the AG3340 Agreement. Roche does not warrant that it will be

                                       3



able to complete any specific  transition  activity  requested by Agouron within
the pre-approved maximun budgeted amount. If Roche determines that an additional
amount will be required to complete  such  transition  activity,  it will notify
Agouron of such fact before  incurring  any costs in excess of the  pre-approved
maximun budgeted amount and will receive Agouron's  approval for such additional
amount;  if Agouron does not reasonably  approve such additional  amount,  Roche
shall be relieved of its obligation to complete such transition activity.

         2.06 In  recognition  of Agouron's  continuing  commercial  interest in
THYMITAQ and AG3340 and the termination of Roche's commercial  interest therein,
and  notwithstanding  any provision contained in the LOI, the THYMITAQ Agreement
and/or  the  AG3340  Agreement,  Roche,  its  Affiliates,  and their  employees,
clinical investigators and consultants *











         2.07 The  parties  agree that no New MMP  Compound  Patent  Rights have
arisen  from  the  conduct  of  the  parties'  research   activities  under  the
Collaboration,  and that effective December 1, 1997, the parties'  collaborative
research activities  conducted pursuant to the provisions of Section 4.05 of the
AG3340 Agreement shall terminate.

         2.08 The parties agree effective December 1, 1997 to terminate the Cell
Cycle Control Research Program,  and that the last day of the Cell Cycle Control
Research Term shall be December 1, 1997.

         2.09 The  parties  agree  that  Agouron  shall be deemed to have  fully
earned and shall be entitled to retain all research  support  funding paid to it
by Roche  pursuant to the provisions of Section B(2) of Exhibit A to the LOI and
that after  November 30, 1997  Agouron  shall have no  obligation  to assign its
scientists to work on the Cell Cycle Control Research Program. Additionally, the
parties agree that Roche shall not be obligated to pay Agouron for the amount of
the  research   support   funding   obligation   which  it  would  otherwise  be
contractually  obligated to pay Agouron on the second anniversary of the signing
of the LOI.

         2.10 The  parties  agree  that no  Program  Compounds,  as such term is
defined  in Section  B(1) of Exhibit A to the LOI,  shall be deemed to have been
invented by Roche  and/or  Agouron,  separately  or  jointly,  in the Cell Cycle
Control Research Program during the

                                       4



Cell Cycle Control Research Term.  *













                The  parties  further  acknowledge  that Roche  and/or  Agouron,
separately  or jointly,  may each in the future file  patent  application(s)  on
compounds invented by its employees during the Cell Cycle Control Research Term,
that such  compounds  shall be assigned to and owned by the  employer(s)  of the
employee(s)  inventing  such  compounds and that the owner(s) of such  compounds
shall  determine  the most  appropriate  manner  to  prepare,  file,  prosecute,
maintain  and  extend  patent  applications  and issued  patents to protect  its
commercial interests in such compounds.

         2.11 The  parties  agree that no Cell Cycle  Control  Research  Program
Patent Rights have arisen from the conduct of the parties'  research  activities
under the Cell Cycle Control Research Program.

         2.12  During  the  Research  Term of the Cell  Cycle  Control  Research
Program, the parties acknowledge that the parties have made *










         2.13 The  parties  agree that each  party  shall be free,  without  any
further  obligation to the other,  to continue work in pursuit of the objectives
of the Cell Cycle Control  Research  Program (CDK4) on its own or with any third
party, and to retain, use and disclose to any such third party,  information and
materials which have been developed in the Cell Cycle Control

                                       5



Research Program (CDK4),  provided that a party shall not disclose to such third
party the confidential and proprietary  information of the other party and shall
not use such confidential and proprietary information for purposes other than in
pursuit of the objectives of the Cell Cycle Control Research Program (CDK4).

         2.14 Upon written request from a party, the other party shall return to
the  requesting  party all  remaining  samples  of any  materials  or  compounds
provided to such party during the  Collaboration.  Each parties shall return all
copies of patent  applications  received from the other party as a result of the
negotiation and conduct of the Collaboration. *




         2.15   Except  as  is   necessary   for   Agouron's   development   and
commercialization  of AG337  and  AG3340  (and  other  backup  compounds)  or as
otherwise stated in this Amendment,  each party shall have no further obligation
to disclose  to the other party  information,  data or results,  patents  and/or
patent  applications  and/or to report or consult on its research,  development,
commercialization and/or patent activities under the Collaboration.

         2.16 Roche agrees to complete and provide  Agouron,  in written  and/or
electronic  format as appropriate,  within 10 days after it becomes available to
Roche, the interim and final results, as well as supporting data, for all of its
ongoing toxicology and other pre-clinical studies *




         2.17  Except for  supplies of AG3340  needed by Roche to  complete  its
ongoing  toxicology and other pre-clinical  studies for AG3340,  Roche agrees to
ship to Agouron (or its designee)* all existing bulk supply and finished product
of AG3340 which it then  currently  possesses.  If  requested by Agouron,  Roche
agrees to use its reasonable efforts to complete the in-process *

                                                                Additionally, if
requested by Agouron, *                 Roche will use its reasonable efforts to
complete production of *

                                                             Roche   agrees   to
ship to Agouron (or its designee) as soon as it is available for shipment the *
Product(and copies of applicable batch records,  manufacturer's certificates and
       certificates  of  analysis),  *  and  all  remaining  raw  materials  and
       intermediates which were specifically purchased for AG3340
manufacturing activities that remain in Roche's possession

                                       6



after  completion of the  manufacture of the above  described  batches.  Agouron
plans to use the AG3340 Product in clinical trials and for other purposes.

         2.18 Roche agrees to provide  Agouron with all relevant  available data
created  in  the  applicable  Development  Program  and  samples  to  facilitate
Agouron's   manufacture  of  AG337,  AG3340,  and  any  Backup  MMP  Inhibitors,
including*













         2.19 Prior to May 20, 1998, Roche agrees to make its relevant personnel
available for reasonable  consulting to assist in the  manufacture of AG3340 and
any Backup MMP  Inhibitors and in the  transition of the  manufacturing  process
from Roche.

         2.20 The parties  shall jointly  prepare and release a statement  about
the amendment of the Collaboration  between Agouron and Roche.  Agouron shall be
entitled  to release  any  further  information  about the  THYMITAQ  and AG3340
Development  Programs which it deems  appropriate;  provided,  however,  Agouron
shall  not  use the  Roche  name in  releases  about  the  THYMITAQ  and  AG3340
Development Programs without the prior written consent of Roche. Roche shall not
release  any  further  information  to any  third  party  who is  not  under  an
obligation  of  confidentiality  with respect  thereto about any of the terms of
this Amendment or of the THYMITAQ and AG3340  Development  Programs  without the
prior  written  consent of Agouron,  which  consent may be withheld in Agouron's
sole  discretion.  This  prohibition  includes,  but is not  limited  to,  press
releases,  educational  and scientific  conferences,  promotional  materials and
discussions with the media,  investors and analysts. If Roche determines that it
is  required by law to release  information  to any third  party  regarding  the
subject  matter of the THYMITAQ and AG3340  Development  Programs,  it shall use
reasonable  efforts  to notify  Agouron  of this  fact  prior to  releasing  the
information.  The notice to Agouron  shall  include the text of the  information
proposed for release.  If possible  Agouron  shall have the right to confer with
Roche regarding the necessity for the disclosure and the text of the information
proposed for release.

         2.21 Effective  December 1, 1997,  Agouron hereby irrevocably elects to
release and terminate its rights under the provisions of Section C(1) of Exhibit
A to the LOI to receive

                                       7



marketing or  acquisition  rights in a Roche Cancer Product in the United States
and under Section C(2) of Exhibit A to the LOI to receive co-promotion rights in
a CDK2 Inhibitor in North America.

         2.22 The parties agree to execute such further documents,  instruments,
assignments,  confirmations,  certificates and assurances which are necessary or
desirable to carry out the purposes of this  Amendment and to document,  confirm
and certify the transfer of rights and obligations provided for hereunder.

         2.23 Except as expressly  amended by the terms  contained  herein,  the
provisions of the LOI  (including  Exhibit A), the THYMITAQ  Agreement,  and the
AG3340  Agreement  (including  Section  5.01(c))  shall remain in full force and
effect  unless  the  further  application  of any  specific  provision  can  not
reasonably  be  construed  to remain in full force and effect after a good faith
consideration  of  the  termination  of  the  THYMITAQ  and  AG3340  Development
Programs,  the Cell Cycle Control  Research Program and/or Agouron's rights in a
Roche Cancer Product.

                                       8




         IN WITNESS  WHEREOF,  the  parties  have caused  their duly  authorized
representatives to enter into this Amendment to the Agouron-Roche  Collaboration
effective as of the dates set forth above.


F. HOFFMANN-LA ROCHE LTD                        AGOURON PHARMACEUTICALS, INC.


By:      /s/ R. Schaffner                       By:      /s/ R. Kent Snyder
Name:    R. Schaffner                           Name:    R. Kent Snyder
Title:   Head of Licensing                      Title:   Sr. Vice President

By:      /s/ St. Arnold                         By:      /s/ Gary Friedman
Name:    St. Arnold                             Name:    Gary Friedman
Title:   ppa                                    Title:   Corp. Vice President


HOFFMANN-LA ROCHE INC.


By:      /s/ George W. Johnston
Name:    George W. Johnston
Title:   Vice President

By:      /s/ William H. Epstein
Name:    William H. Epstein
Title:   Assistant Secretary

                                       9