Copromotion Agreement - Roche Laboratories Inc. and Gilead Sciences Inc.


                              COPROMOTION AGREEMENT


    This Agreement made this 27th day of September, 1996 by and between Roche
Laboratories Inc.,  a New Jersey corporation having its principal place of
business at 340 Kingsland Street, Nutley, New Jersey 07110 (hereinafter referred
to as 'ROCHE') and Gilead Sciences Inc., a Delaware corporation having a
principal place of business at 353 Lakeside Drive, Foster City, California 94404
(hereinafter referred to as 'GILEAD').


                                   WITNESSETH


    WHEREAS,  ROCHE is presently marketing the product Roferon-Registered
Trademark--A (Interferon alfa-2a, recombinant) for certain cancer indications
and is now developing this product for treating hepatitis C; and

    WHEREAS, GILEAD has a professional sales force that calls on physicians and
other health care professionals in order to promote GILEAD products; and

    WHEREAS, ROCHE desires to enhance its marketing of the Product (as
hereinafter defined) for treating hepatitis C in the Territory (as hereinafter
defined) by enlisting the support and participation of the GILEAD sales force.

    NOW, THEREFORE, for and in consideration of the mutual covenants contained
herein, ROCHE and GILEAD hereby agree as follows:


                              ARTICLE 1-DEFINITIONS


1.01  In the terms defined herein, the singular shall include the plural and
      vice versa.

1.02  The effective date of this Agreement shall be the date the Agreement is
      fully executed.



1.03  The term 'Approval Date' shall mean the date the U.S. Food and Drug
      Administration has approved the Product for marketing in the Field as
      specified in the notice transmitted pursuant to Paragraph 7.01.

1.04  The term 'Call' shall mean a visit by a professional sales representative
      to a physician licensed to prescribe, dispense or administer legend drugs,
      which visit is for the purpose of making a Primary Presentation on the
      Product and involving no more than two other product presentations.  Such
      physician shall be selected from a target audience defined by the
      Committee (as hereinafter defined).

1.05  The term 'Calendar Year' shall mean a one year period commencing on
      January 1.  For instance, the first Calendar Year shall mean the period
      from January 1, 1997 to December 31, 1998.  The second Calendar Year shall
      mean the period from January 1, 1998 to December 31, 1999.

1.06  The term 'Field' shall mean the treatment of hepatitis C.

1.07  'Net Sales' shall be calculated by taking the gross sales of Product
      invoiced by ROCHE and sublicensees in Territory to third parties, less
      deductions of returns (including withdrawals and recalls), rebates (price
      reductions, including Medicaid and similar types of rebates e.g.
      chargebacks), volume (quantity) discounts, discounts granted at the time
      of invoicing, sales taxes and other taxes directly linked to and included
      in the gross sales amount (hereinafter 'Adjusted Gross Sales').  In
      addition, from the Adjusted Gross Sales, there shall be a lump sum
      deduction of [               ] for those sales related deductions which
      are not accounted for on a product by product basis (for example, without
      limitation, outward freights, transportation insurance, packaging
      materials for dispatch of goods, custom duties, discounts granted later
      than at the time of invoicing, cash discounts, and product liability
      insurance).


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1.08  The term 'Primary Presentation' shall mean a full Product presentation
      during which key product attributes are verbally presented; provided,
      however, that no more than one  presentation in any Call shall be
      considered a Primary Presentation, which shall be the presentation on
      which the most time is spent during the Call.

1.09  The term 'Product' shall mean Roferon-Registered Trademark--A (Interferon
      alfa-2a, recombinant)  for use in the Field.

1.10  The term 'The Term of this Agreement' shall mean the period specified in
      Paragraph 7.01.

1.11  The term 'Territory' shall mean the United States and its territories,
      possessions and commonwealths.


                       ARTICLE 2 - GRANTS  AND OBLIGATIONS


2.01  ROCHE hereby grants to GILEAD during the Term of this Agreement and under
      the conditions herein imposed the right to promote and detail jointly with
      ROCHE the Product under the trademark 'ROFERON-A ' for use in the Field in
      the Territory.  ROCHE shall not enter into any other copromotion or
      similar arrangement with a third party regarding the Product for use in
      the Field in the Territory during the Term of this Agreement.  This
      provision shall not preclude ROCHE from using contract personnel to detail
      the Product.  During the term of this Agreement, GILEAD shall not enter
      into any other copromotion or similar arrangement with a third party in
      the Field and within the Territory nor shall GILEAD market any other
      product in the Field and within the Territory.

2.02  Subject to the provisions of and during the Term of this Agreement, each
      party shall use its best efforts consistent with accepted business
      practices and legal requirements to deploy its sales force to promote and
      detail the Product for use in the Field in the

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      Territory in such manner and with such expedition as the party itself
      would have adopted in launching, promoting and detailing a major
      pharmaceutical Product of its own invention. In this regard, GILEAD will
      provide a qualified field sales staff for detailing and promoting the
      Product resulting in at least the number of Calls required pursuant to
      Paragraph 2.03.

2.03  During each calendar year, GILEAD shall make at least [      ] Calls and
      ROCHE shall make at least [     ] Calls.  At the end of the third quarter
      of each Calendar Year, ROCHE and GILEAD shall discuss the number of calls
      each party is required to make in the subsequent Calendar Year.  In the
      event that the number of Calls which either party is required to make
      changes, then the parties will agree on an appropriate adjustment to the
      compensation structure provided in this Agreement.

                              ARTICLE  3 - PAYMENTS

3.01  Within thirty (30) days of the effective date of this Agreement, ROCHE
      shall pay GILEAD a one time, nonrefundable (except as described in this
      Section 3.01) fee of [        ] as compensation for its sales efforts 
      during the remainder of calendar year 1996.  In the event that ROCHE does
      not receive approval to market the Product by June 30, 1997, then ROCHE or
      GILEAD may elect to terminate this Agreement and in such case GILEAD shall
      return the [       ] fee minus any direct expenses incurred with regard
      to preparing for the launch of the Product.

3.02  ROCHE shall pay GILEAD a royalty on net sales from the first Calendar Year
      through the third Calendar Year according to the following three tiers of
      gross sales.  Gross sales falling within each tier shall first be
      converted to Net Sales, against which the appropriate royalty shall be
      applied.


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                                                       ROYALTY AS
                                                       % OF NET SALES

      Gross sales from [     ] of base gross             [   ]
      sales forecast

      Gross sales from [      ] of base gross            [   ]
      sales forecast

      Gross sales greater than [    ] of base gross      [   ]
      sales forecast

      The parties have agreed to base gross sales forecasts for Product of 
      [           ] in the first Calendar Year and [          ] in the 
      second Calendar Year.  A base gross sales forecast for the third Calendar
      Year shall be calculated as described in the following sentences and 
      equation:

      At the end of the third quarter of second Calendar year, the Committee
      shall determine a gross base sales forecast for the third Calendar Year.
      For purposes of this calculation, an estimate of annual gross sales for
      the second Calendar Year will be projected based upon gross sales for the
      first three quarters of that year.  In summary, the 1999 base gross
      forecast shall be calculated as the product of the following three
      variables:

          (Roferon-A percentage market share) [      ]
           in interferon Hepatitis C treatments in 1998


                         X

          (The Compounded Annual Growth
           Rate for the total dollar market for
           interferon Hepatitis C treatments
           from the period beginning January 1, 1997
           to December 31, 1998)

                         X

          (Total dollar market for interferon
          Hepatitis C treatments in 1998)


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      By way of example, if in 1997 gross sales of Product are [           ] 
      then the royalty payable to GILEAD shall be calculated as follows:


      -   1997 base gross sales forecast  = [               ]
      -   [   ] of 1997 base gross sales forecast  = [                 ]
      -   Net sales are assumed to be [   ] of gross sales, having assumed that
          gross sales are reduced by [  ] to calculate Adjusted Gross Sales and
          are further reduced by [   ] as a lump sum for additional allowed
          indirect expense deductions, pursuant to Paragraph 1.07.


           Gross Sales      Net Sales      Royalty Rate      Royalty Due
           -----------      ---------      ------------      -----------
      [



                                                                          ]


     With regard to an example for the determination of the base gross sales
     forecast for 1999, assuming:

     -    The total market in 1998 for all interferon Hepatitis C products in
          the Territory is [              ]

     -    The compounded annual growth rate for the total market for interferon
          Hepatitis C products in the Territory from January 1, 1997 to December
          31, 1998 is [    ]

     -    The annual gross sales of  Product in 1998 are [         ] and
          therefore the percentage market share for the Product among all
          interferon Hepatitis C products in the Territory is [    ].

     then the base gross sales forecast for 1999 shall be the following:
     [                                                          ]


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3.03  ROCHE will have no liability with respect to payments due GILEAD under
      Paragraph 3.02 which might have been earned on the Product by GILEAD but
      were not earned, or for any damage of any nature incurred by GILEAD in
      anticipation of Net Sales which might have been earned but were not
      earned, if, for any reason, including the negligence (but not the willful
      misconduct) of ROCHE: (a) ROCHE is unable to ship the Product in the
      Territory, (b) the Product is withdrawn from the market in the Territory,
      (c) sales of the Product in the Territory do not reach a level reasonably
      expected by previous sales, or any level or (d) Force Majeure as set forth
      in Article 8.  In the event that any of the foregoing occur, excluding
      (c), in such a way that the financial assumptions underlying this
      Agreement are no longer valid, then the parties will renegotiate the terms
      of this Agreement in good faith.

3.04  Within [                    ] after the close of each [                 ]
      during the Term of this Agreement, ROCHE shall submit to GILEAD a
      statement showing: (i) the amount of gross sales and Net Sales including,
      an itemized calculation of Adjusted Gross Sales, (ii) the deductions
      provided for in Paragraph 1.07 during such [       ] and on a cumulative
      basis year-to-date, and (iii) the calculation of payments to GILEAD
      pursuant to Paragraph 3.02. The calculations provided for herein shall be
      subject to audit pursuant to Paragraph 4.15.

3.05  For the one year period commencing upon the expiration of this Agreement
      ('Residual Year'), ROCHE shall pay GILEAD [                  ] of the 
      total amount paid to GILEAD for the previous calendar year pursuant to
      paragraph 3.02.  The payment for the Residual Year shall be made in equal
      [           ] installments within [                   ] after the end of 
      each [            ] of the Residual Year.

3.06  Under the provisions of this Agreement, all sums due to GILEAD for sales
      of the Product for use in the Field within the Territory hereunder will be
      payable by ROCHE in U.S. Dollars via wire transfer  to GILEAD's account at
      the following address:


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                          Wells Fargo Bank
                          444 Market Street, 7th Floor
                          San Francisco, CA 94163
                          Attn: Jeff Appleton

                          ABA # 121000 248
                          Dept. # 068
                          Acct. # 324-112069
                          Acct. Name: Gilead Sciences, Inc.

      or any other place or bank account as GILEAD may designate to ROCHE in
      writing. A copy of relevant report upon which said payment was based will
      also be sent by ROCHE to GILEAD at the following address:

                          Gilead Sciences, Inc.
                          353 Lakeside Drive
                          Foster City, CA 94404
                          Attn: Chief Financial Officer
                          (415) 574-3000

3.07  Notwithstanding anything in this Agreement to the contrary, in the event
      that ROCHE's actual Net Sales in the Territory are reduced, due to
      credits, refunds, voluntary or government mandated recalls for any reason
      at any time within six (6) months after the completion of any Calendar
      Year for which Net Sales have been accrued pursuant to the terms of this
      Agreement, then the Net Sales for the Calendar Year in which such credits,
      refunds, recalls, etc. occur shall be reduced accordingly and GILEAD shall
      return to ROCHE within sixty (60) days of receipt of a notice from ROCHE
      requesting such return, any dollar amounts which were paid to GILEAD in
      respect of Net Sales during such Calendar Year which are in excess of the
      dollar amounts which would have been paid to GILEAD if the Net Sales for
      such period reflected the Net Sales actually obtained by ROCHE  taking
      into account such credits, recalls, refunds or other deductions.

3.08  Within sixty (60) days of the execution of this Agreement, ROCHE and
      GILEAD shall agree to an appropriate methodology including the selection
      of an independent third party source to determine total sales of the
      Product in the Field within the Territory and market

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      share relative to all interferon products sold for the treatment of
      Hepatitis C.  The establishment of sales and market share data described
      in this Paragraph shall be at the expense of ROCHE.

3.09  If the difference between the gross sales of Product and the Adjusted
      Gross Sales of Product is more than [              ] of the gross sales
      of Product for any given quarter as a result of Product rebates or other
      pricing matters due to competition in the marketplace, then the parties
      will renegotiate in good faith the terms of this Agreement.


             ARTICLE   4 - COOPERATION, RIGHTS AND RESPONSIBILITIES


      It is among the objectives of the parties to promote and detail the
      Product for use in the Field within the Territory in the most effective
      and efficient fashion. To achieve this and other objectives, the parties
      agree as follows:

4.01  The parties shall each appoint an authorized representative
      ('Coordinator') with whom communications between the parties relating to
      marketing and sales of  the Product will be directed. Each party will
      notify the other as to the name of the individual so appointed. Each party
      may replace its Coordinator at any time, upon written notice to the other
      party.

4.02  (a) The Coordinators shall establish a Committee directed by the Roche
      Coordinator and consisting of  an equal number of representatives of each
      party which will meet at least quarterly, at mutually agreeable times and
      locations, to discuss and coordinate the joint promotion and detailing of
      the Product for use in the Field in the Territory and the strategies and
      programs that should be developed to maximize Net Sales. Illustratively,
      the Committee shall (i) coordinate the launch of the Product for use in
      the Field in the Territory and (ii) guide all continuing joint promotion
      and detailing efforts with respect to the Product for use in the Field in
      the Territory.  Although the parties intend to work cooperatively, ROCHE
      will have authority and final responsibility for developing


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      marketing strategies and tactics including but not limited to detailing
      strategies  with respect to the Product.

      (b)   The Committee shall develop and formulate  marketing plans for
      specified periods (collectively the 'Marketing Plan') which shall set
      forth marketing strategies and tactics relating to the Product. ROCHE,
      however, shall have the final responsibility for, and control over, the
      development and content of the Marketing Plan.

      (c)    Efforts will be made at the sales territory level to coordinate the
      Calls by the ROCHE sales force with the Calls by the GILEAD sales force to
      ensure the most effective coverage of the target audiences and to minimize
      non-productive efforts.

      (d)  A party shall have the right to comment upon and make recommendations
      to the other party regarding the other party's activities under this
      Agreement, which recommendations the other party shall thoroughly evaluate
      and consider.

      (e)  Each party shall bear its own costs associated with its participation
      in the Committee and its activities performed under this Agreement.

4.03  (a) During the Term of and subject to any other provision of this
      Agreement, each party will provide the other with all information relevant
      to the detailing and promotion of the Product for use in the Field within
      the Territory within a reasonable time after such information becomes
      known to the party, provided such information is not received from an
      independent third party under a secrecy obligation.  Specifically, the
      sales force of each party will receive the same information at the same
      time with respect to the Product.

      (b) During the Term of this Agreement, each party shall promptly notify
      the other party of all information coming into its possession concerning
      unexpected side effects, injury, toxicity or sensitivity reaction
      including unexpected incidence and severity thereof associated with
      commercial or clinical uses, studies, investigations or tests with the

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      Product (animal or human), throughout the world, whether or not determined
      to be attributable to the Product ('Adverse Reaction Reports').  In the
      case of Adverse Reaction Reports within the scope of 21 CFR
      314.80(c)(iii), GILEAD shall transmit such Adverse Reaction Reports so
      that they are received by ROCHE within three (3) business days after
      receipt by GILEAD, or such other reporting period as may be required by
      law.  ROCHE shall transmit Adverse Reaction Reports to GILEAD on a
      periodic basis, but no less often than once every three (3) months;
      provided, however, that ROCHE shall promptly notify GILEAD of any Adverse
      Reaction Report requiring the alteration of detailing activities by the
      GILEAD sales force.  All such communications shall be held in the
      strictest confidence by GILEAD and shall be subject to the terms of
      Paragraph 4.14.

4.04  GILEAD warrants and represents that it will maintain records of Calls made
      by its sales force and that these records will accurately represent the
      number of Calls made and the relative emphasis given to each Product
      during a Call.  For all Calendar Years covered by this Agreement,  GILEAD
      shall issue reports to ROCHE within [                  ] after the end of
      [             ] of such Calendar Year showing the number of Calls made to
      each audience and the relative emphasis assigned to the Product in such
      Calls. ROCHE shall be entitled to audit the source data and documents 
      used to compile such reports pursuant to the provisions of Paragraph 4.15
      of this Agreement.

4.05  ROCHE retains and shall retain all proprietary rights and proprietary
      interests in the Product until the point of sale and in all supporting
      sales and promotional and educational material. GILEAD will not have nor
      represent that it has any control or proprietary or property interests in
      the Product. Nothing contained herein shall be deemed to grant GILEAD,
      either expressly or implied by a license or other right or interest in any
      patent, trademark, copyright or other similar property of ROCHE except as
      may be necessary for GILEAD to promote and detail the Product as provided
      for in this Agreement.

4.06  (a) During the Term of this Agreement, at ROCHE's cost, ROCHE shall create
      and develop all sales and promotional materials relating to the Product
      for distribution for use


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      in the Field. ROCHE shall provide GILEAD with such materials, in amounts
      which are reasonable under the terms of the Marketing Plan. Other than
      with the advice and consent of ROCHE, GILEAD shall not create or develop
      sales, promotional or other similar materials relating to the Product for
      distribution to independent third parties.

      All sales and promotion material for distributing the Product for use in
      the Field which is prepared primarily through a printing technique (except
      for memo pads and the like) shall be supplied by ROCHE, free of all
      charge, to GILEAD.

      All sales and promotional materials relating to the distribution of the
      Product for use in the Field which are multi-dimensional in form,
      including memo pads and the like, and materials which are prepared
      primarily by techniques other than printing shall be supplied to GILEAD by
      ROCHE in accordance with paragraph 4.07 of this Agreement.

      (b) GILEAD shall not be required to distribute any sales and promotional
      material prepared after the date of this Agreement which (i) does not
      present GILEAD to the medical and paramedical communities and to the trade
      as joining with ROCHE in the detailing and promotion of the Product, (ii)
      does not mention the Product, or (iii) includes reference to another ROCHE
      pharmaceutical in addition to the Product. At ROCHE's request, and at
      GILEAD's sole option, GILEAD may distribute sales and promotion material
      of the type identified in this subparagraph (b). Should GILEAD elect to so
      distribute such material, it shall be supplied to GILEAD by ROCHE free of
      all charge. In no event shall ROCHE be required to distribute any material
      which contains a reference (i) to GILEAD (other than in connection with
      the joint detailing and promotion of the Product in accordance with this
      Agreement) or (ii) any GILEAD pharmaceutical.

4.07  To achieve the objectives of this Agreement, it may be necessary to
      distribute multi-dimensional sales and promotional materials, including
      memo pads and the like and/or materials which are prepared primarily by
      techniques other than printing (all of these materials being hereinafter
      identified as 'Materials') to health care personnel and

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      the trade on an ongoing basis ('Program'). If in ROCHE's sole judgment it
      determines that such a Program is best to achieve these objectives, ROCHE
      shall provide GILEAD, free of charge, with all of GILEAD's reasonable
      requirements for Materials. ROCHE shall cause the production of all
      Materials and shall ship GILEAD's requirements of Materials to such
      GILEAD's facilities as GILEAD may designate, F.O.B., the ROCHE
      distribution site. Materials shall be allotted on a per capita basis to
      the ROCHE sales force and the GILEAD sales force as modified by the
      expected amount of time and effort to be used by each sales force in
      detailing and promoting the Product for use in the Field. All Materials
      delivered to GILEAD shall be packaged in the same form and be of the same
      quality as those which ROCHE normally distributes to health care personnel
      or to the trade in the Territory.

4.08  Each party shall contribute facilities, supplies, personnel (including
      management and sales representatives) and other resources without charge
      or expense to the other as each party, in its absolute discretion,
      believes necessary for the proper performance of terms of this Agreement,
      and each party shall bear its own costs incurred in the performance of any
      obligations hereunder.    Neither party shall have any responsibility for
      the firing or compensation of the other party's employees or for any
      employee benefits.  No employee or representative of a party shall have
      any authority to bind or obligate the other party to this Agreement for
      any sum or in any manner whatsoever, or to create or impose any
      contractual or other liability on the other party without said party's
      authorized written approval. For all purposes, and notwithstanding any
      other provision of this Agreement to the contrary, GILEAD's legal
      relationship under this Agreement to ROCHE shall be that of independent
      contractor.

4.09  ROCHE shall have the sole responsibility for the manufacture and
      distribution of Product in the Territory.   ROCHE shall also be
      responsible for insuring that sufficient stock of the Product will be
      available in its inventory to promptly fill orders in the Territory from
      the trade except for Force Majeure as defined in Article 8.

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4.10  (a) With respect to the Product,  ROCHE and GILEAD shall both employ the
      Trademark 'Roferon-Registered Trademark--A'  on all promotional literature
      relating to the Product for use in the Territory such as detailing aids
      and advertising directed to the Product. All such promotional literature
      shall identify the Product as being promoted by ROCHE/GILEAD. At ROCHE's
      discretion, all literature which sets forth the Product and sets forth
      with at least equal emphasis to the Product, one or more other Products
      distributed or sold by ROCHE need not set forth or identify the Product as
      being promoted by ROCHE/GILEAD but can simply identify the Product as a
      ROCHE Product without the name of GILEAD appearing on said literature.

      (b) During the term of this Agreement after approval of the supplemental
      new drug application (NDA) by the United States Food and Drug
      Administration (FDA) directed to the Product and before launch of the
      Product, ROCHE shall provide reasonable assistance to GILEAD, free of
      charge, for training and orientation of the GILEAD sales force. ROCHE will
      provide GILEAD, free of charge, with reasonable quantities of training
      materials which have been created and developed by ROCHE relating to the
      Product and its use in the Field. During the term of this Agreement,
      GILEAD will not permit any of its sales personnel to promote the Product
      unless such sales personnel have been qualified under criteria and/or
      tests supplied by ROCHE, which either will be the same as those used to
      qualify ROCHE sales personnel or will be approved by ROCHE.  The costs of
      training the GILEAD sales training personnel incurred by GILEAD shall be
      borne by GILEAD.

      (c) Neither party shall distribute or have distributed any such
      information, except for promotional literature prepared by ROCHE under
      subparagraph (a) of this paragraph, which bears the name of the other
      without the prior written approval of the other, which approval shall not
      be unreasonably withheld. The Product shall be represented solely as a
      ROCHE Product. When packaged, the Product will bear the trademark and
      label of ROCHE only. All promotional materials or other information
      regarding the Product, if any, which is distributed other than to medical
      or paramedical communities or trade, will

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      not be required to identify GILEAD's involvement in the detailing or
      promotion of the Product, but may so identify said involvement if ROCHE in
      its sole discretion deems it appropriate to do so.

      (d) (i) ROCHE at its option may issue press releases or other public
      announcements relating to the Product or the arrangement contemplated by
      this Agreement (including a joint press release with GILEAD upon execution
      of this Agreement), provided however, that ROCHE shall not issue a press
      release or public announcement which relates to the arrangement
      contemplated by this Agreement, except for references to GILEAD and the
      relationship created by this Agreement in ROCHE's annual and quarterly
      reports and other SEC documents, without the prior written approval of
      GILEAD, which approval shall not be unreasonably withheld.

      (ii)  GILEAD at its option may issue press releases or other public
      announcements relating to the Product or the arrangement contemplated by
      this Agreement (including a joint press release with ROCHE upon execution
      of this Agreement), provided however, that GILEAD shall not issue a press
      release or public announcement which relates to the arrangement
      contemplated by this Agreement, except for references to ROCHE and the
      relationship created by this Agreement in GILEAD's annual and quarterly
      reports and other SEC documents, without the prior written approval of
      ROCHE, which approval shall not be unreasonably withheld.

4.11  (a) ROCHE shall have the sole right and responsibility, and shall bear all
      costs related thereto, to take such actions with respect to the Product as
      would normally be done in accord with accepted business practices and
      legal requirements to obtain and maintain the authorization and/or ability
      to market a major pharmaceutical Product in the Territory, including,
      without limitation, the following:

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      (l)   responding to Product and medical complaints relating to the
            Product. GILEAD agrees that it shall refer any such complaints which
            it receives to ROCHE as soon as reasonably practicable;

      (2)   handling all returns of the Product. If the Product is returned to
            GILEAD, it shall be shipped to ROCHE's nearest facility, with any
            reasonable or authorized shipping or other documented direct cost to
            be paid by ROCHE. GILEAD shall incur no liability of any nature in
            the handling of such returns. GILEAD, if requested, shall advise the
            customer who made the return that the Product has been returned to
            ROCHE;

      (3)   handling all recalls of the Product. At ROCHE's request and GILEAD's
            option, GILEAD will assist ROCHE in receiving the recalled Product
            and any direct documented costs incurred by GILEAD, with respect to
            participating in such recall shall be reimbursed by ROCHE;

      (4)   communicating with any governmental agencies and satisfying their
            requirements regarding the authorization and/or continued
            authorization to market the Product in commercial quantities in the
            Territory;

      (5)   reporting Adverse Reaction Reports to U.S. regulatory authorities as
            required by applicable U.S. law or regulation;

      (6)   handling Product distribution, inventory and receivables.

      (b) Each party shall respond to medical questions or inquiries relating to
      the Product directed to such party. Within a reasonable time from the date
      of this Agreement, but in no event later than the Approval Date, ROCHE
      shall provide GILEAD with all reasonably necessary information which would
      enable GILEAD to respond properly and promptly to any such questions or
      inquiries. All such information shall be held in the

                                       16



      strictest confidence by GILEAD and shall be subject to the terms of
      Section 4.13 hereof except with regard to providing the proper response to
      medical questions or inquiries relating to Product.  ROCHE shall use its
      best efforts to keep such information current. GILEAD and ROCHE shall
      coordinate responses to anticipated inquiries and questions.

4.l2  Notwithstanding the Marketing Plan or any other provision herein to the
      contrary, ROCHE will have the sole right and responsibility for
      establishing and modifying the terms and conditions with respect to the
      sale of the Product, including the price at which the Product will be
      sold, any discount attributable to payments on receivables, distribution
      of the Product and the like.

4.13  If, for any reason, GILEAD should receive orders for the Product, GILEAD
      shall use its best efforts to forward such orders to ROCHE as soon as
      practicable.

4.14  Any information provided to GILEAD by ROCHE (or by anyone who was under a
      non-disclosure obligation to ROCHE) under this Agreement, except that
      information:

      (a) which becomes public through no fault of GILEAD; or

      (b) which was known by GILEAD prior to its disclosure to GILEAD by ROCHE;
      or

      (c) which is lawfully obtained by GILEAD from a third party which is
      independent of ROCHE and said third party is in lawful possession of said
      information; or

      (d) which is required to be disclosed by applicable law or regulation; or

      (e) which is intended for distribution to the trade:
      shall be treated with the strictest confidence and GILEAD shall not use
      any such information for any purposes other than that provided in this
      Agreement.

                                       17



      GILEAD shall keep such information in a special file which shall be solely
      under the direction and control of the GILEAD Coordinator. GILEAD shall
      not distribute any such information except to its employees who have a
      need to know such information. Any GILEAD employee who receives such
      information shall be advised of the confidential nature thereof and the
      prohibitions contained in this section. The Coordinator will use best
      efforts to keep a record of those individuals who have received copies of
      the information or any portions thereof, and all copies or any portions
      thereof will be identified by GILEAD as confidential. Upon termination of
      this Agreement, and upon the request of ROCHE, GILEAD shall return or
      destroy all such information and copies thereof in its possession, except
      that GILEAD may keep one copy of such information in GILEAD's Law
      Department files solely for archival purposes. Such archival copy will be
      deemed to be the property of ROCHE, and will not be copied or distributed
      in any manner without the express prior written permission of ROCHE. The
      prohibitions contained herein shall survive the termination of this
      Agreement and last for a period of ten (10) years from the date of
      termination of this Agreement.

4.15  Each party shall keep, and shall cause its Affiliates and sublicensees to
      keep, complete and accurate records pertaining to the Calls (by GILEAD or
      ROCHE) or sale or other disposition of Product and of the Royalty and
      other amounts payable under this Agreement in sufficient detail to permit
      the other party to confirm the accuracy of all Calls completed and
      payments due hereunder. At either party's request, the other party will
      cause its independent certified public accountants to prepare abstracts of
      its relevant business records for review by the other party's independent
      certified public accountants.  If, based on a review of such abstracts, a
      party reasonably believes that a full audit of said business records would
      be necessary for the confirmation of the accuracy of all Calls and
      payments due hereunder, that party's independent certified public
      accountants shall have full access to review all work papers and
      supporting documents pertinent to such abstracts, and shall have the right
      to discuss such documentation with the other party's independent certified
      public accountants.  [


                      [*] CONFIDENTIAL TREATMENT REQUESTED

                                       18













                                                 ]  Such audit rights may be
      exercised no more often than once a year, within three (3) years after the
      payment period to which such records relate, upon notice to the party
      being audited and during normal business hours.  The party requesting such
      audit will bear the full cost of such audit unless such audit discloses an
      underpayment of more than five percent (5%) from  the amount of Calls made
      or royalties due.  The terms of this Paragraph shall survive any
      termination or expiration of this Agreement for a period of three (3)
      years.

4.16  Each party will utilize its own sales force to promote and detail the
      Product.  During the Term of this Agreement, neither party will recruit or
      employ any sales representative of the other party who has been involved
      in promotion of the Product in the Territory.  In addition, neither party
      will recruit any sales representative of the other party without prior
      consultation with the other party.

                   ARTICLE 5 - WARRANTIES AND INDEMNIFICATION

5.01  Each party warrants and represents to the other that it has the full right
      and authority to enter into this Agreement, and that it is not aware of
      any impediment that would inhibit its ability to perform its obligations
      under this Agreement.

5.02  ROCHE warrants and represents that it has no knowledge of the existence of
      any U.S. patent owned or controlled by anyone other than ROCHE which would
      prevent ROCHE


                      [*] CONFIDENTIAL TREATMENT REQUESTED

                                       19



      from making, using or selling the Product for use in the Field within the
      Territory or would prevent GILEAD and ROCHE from jointly promoting or
      detailing the Product for use in the Field within the Territory.

5.03  ROCHE will defend, indemnify and hold harmless GILEAD and its directors,
      officers, employees and agents against all losses, expenses, claims and
      liabilities, known and unknown, of any kind, including all costs and
      expenses relating thereto arising at any time as a result of any assertion
      relating to the manufacture, handling, use or distribution of Products by
      ROCHE,  or their sublicensees except to the extent that they result from
      acts or omissions of acts of GILEAD, its directors, officers, employees or
      agents.

5.04  GILEAD will defend, indemnify and hold harmless ROCHE and its directors,
      officers, employees and agents against all losses, expenses, claims and
      liabilities, known and unknown, of any kind, including all costs and
      expenses relating thereto arising at any time as a result of any assertion
      relating to the promotion of Products by GILEAD, except to the extent that
      they result from acts or omissions of acts of ROCHE, its directors,
      officers, employees or agents

5.05  Regarding the indemnity and hold harmless under Paragraph 5.03, GILEAD
      shall give prompt written notice to ROCHE of the commencement of  any
      action, suit or proceeding for which indemnification may be sought, and
      ROCHE shall assume the defense thereof; provided, however, that GILEAD
      shall be entitled to participate in any such action, suit or proceeding
      with counsel of its own choice, but at its own expense. If ROCHE fails to
      assume the defense within a reasonable time, GILEAD may assume such
      defense and the reasonable fees and expenses of its attorneys will be
      covered by the indemnity provided for in Paragraph 5.03 above. No such
      action, suit or proceeding shall be compromised or settled in any manner
      which might adversely affect the interests of ROCHE without prior written
      consent of ROCHE which consent shall not be unreasonably withheld.  ROCHE
      agrees to consult with GILEAD with respect to any proposed compromise or
      settlement which would adversely affect the interests of GILEAD.

                                       20



                 ARTICLE 6 - PATENTS AND TRADEMARK INFRINGEMENT


      GILEAD shall advise ROCHE promptly upon its becoming aware of any
      infringement by a third party of a patent or trademark owned by ROCHE and
      respectively covering or identifying the Product in the Territory. If
      warranted in the opinion of ROCHE, ROCHE shall promptly take such legal
      action as is required to restrain such infringement. GILEAD shall
      cooperate fully with and as requested by ROCHE, at ROCHE's expense, in
      ROCHE's attempt to restrain such infringement. GILEAD may be represented
      by counsel of its own selection at its own expense in any suit or
      proceeding brought to restrain such infringement  but ROCHE shall have the
      right to control the suit or proceeding.

                        ARTICLE 7 - TERM AND TERMINATION

7.01  The term of this Agreement shall commence on the effective date of this
      Agreement and continue, unless terminated sooner in accordance with the
      subsequent provisions of this Article, until December 31, 1999.

      Upon termination of this Agreement for any reason or purpose, all rights
      to The Product including but not limited to regulatory submissions and
      trademarks become or remain the property of ROCHE.

      ROCHE shall notify GILEAD in writing of the Approval Date within ten (10)
      days thereof.

      Paragraphs 3.05, 3.06, 4.05, 4.10(d), 4.11(a), 4.14, 4.15, 5.03 and 5.04
      shall survive expiration or termination of this Agreement for any reason.

                                       21



7.02  Either party may terminate this Agreement for Good Cause (as defined in
      Paragraph 7.03 below), effective at any time after providing sixty (60)
      days written notice and, if applicable, an opportunity to cure during such
      sixty (60) day period (if such cure is effected, such notice with respect
      to such Good Cause shall be null and void). If the Agreement is so
      terminated by either party for Good Cause, ROCHE shall pay to GILEAD all
      dollar amounts due to it under Sections 3.02 and 3.05 through the
      effective date of such termination.

7.03  'Good Cause' shall include the failure of the other party to comply with
      any of its material obligations contained in this Agreement (including the
      failure to detail the Product).

7.04  Termination of this Agreement for Good Cause, shall be without prejudice
      to (a) any remedies which any party may then or thereafter have hereunder
      or at law; and (b) GILEAD's right to receive any payment accrued under the
      Agreement prior to the termination date but which became payable
      thereafter;  and (c) either party's right to obtain performance of any
      obligations provided for in this Agreement which survive termination by
      their terms or by a fair interpretation of this Agreement.

7.05  [

                                 ]


                           ARTICLE  8 - FORCE  MAJEURE


      If either party shall be delayed, interrupted in or prevented from the
      performance of any obligation hereunder by reason of an act of God, fire,
      flood, earthquake, war (declared or undeclared), public disaster, strike
      or labor differences, governmental enactment, rule or regulation, or any
      other cause beyond such party's control, such party shall not be liable to
      the other therefor; and the time for performance of such obligation shall
      be extended


                      [*] CONFIDENTIAL TREATMENT REQUESTED

                                       22



      for a period equal to the duration of the contingency which occasioned the
      delay, interruption or prevention.

      Within 15 days of the beginning of the Force Majeure, the party invoking
      its Force Majeure rights must, by registered letter notify the other party
      of this fact. The termination of the Force Majeure must also be notified
      to the other party by registered letter within 15 days of such
      termination. If the Force Majeure renders either of the required
      notifications impossible, notification must be given as soon as possible.

                           ARTICLE  9 - MISCELLANEOUS

9.01  This Agreement supersedes all prior agreements and understandings, both
      written and oral between the parties with respect to the subject matter
      hereof. This Agreement cannot be amended, changed or supplemented, except
      in writing signed by each of the parties hereto.

9.02  This Agreement may be executed in several counterparts, each of which
      shall be deemed to be an original.

9.03  All notices which are required or may be given pursuant to this Agreement
      shall be sufficient upon receipt, if given in writing and delivered by
      hand, by electronic media, or by registered or prepaid addressed as
      follows:

            TO GILEAD:   Gilead Sciences, Inc.
                         353 Lakeside Drive
                         Foster City, CA 94404
                         Attn:  General Counsel
                         Phone: (415) 574-3000
                         Fax:  (415) 572-6622

                                       23



        TO ROCHE:        Roche Laboratories Inc.
                         340 Kingsland Street
                         Nutley, New Jersey 07110
                         Attention: Corporate Secretary
                         Phone: (201) 235-2165
                         Fax:   (201) 235-3500

      The address of either party set forth above may be changed from time to
      time by written notice in the manner prescribed herein from the party
      requesting the change. A notice sent by ordinary mail or a notice not
      given in writing shall be effective upon receipt,  but only if
      acknowledged in writing by a duly authorized representative of the party
      to whom it was sent or given or otherwise upon clear evidence of receipt.

9.04  None of the parties hereto may assign any part or all of this Agreement or
      the benefit thereof or any right or obligation thereunder to any other
      entity or individual without prior written consent of the other party. Any
      purported assignment in violation of the preceding sentence shall be void.

9.05  This Agreement shall be construed, regulated and administered and governed
      in all respects under and in accordance with the law of the State of New
      Jersey.

9.06  Except to  the extent that a party may have otherwise agreed in writing,
      no waiver by such party of any breach by any other party of any of the
      other party's obligations, agreements or covenants hereunder shall be
      deemed to be a waiver by such first party of any subsequent or other
      breach of the same or any other obligation, agreement or covenant; nor
      shall any forbearance by a party to seek a remedy for any breach by
      another be deemed a waiver by said party of its rights or remedies with
      respect to such breach or of any subsequent or other breach of the same or
      any other obligation, agreement or covenant.

9.07  This Agreement shall be binding upon and inure to the benefit of the
      parties to this Agreement and their respective successors.

                                       24



9.08  Headings as used in this Agreement are for convenience only and are not to
      be construed as having any substantive effect by way of limitation or
      otherwise.

9.09  If one or more of the provisions of this Agreement shall, by any court or
      under any provision of law, be found to be void or unenforceable, the
      Agreement as a whole shall not be affected thereby, and the provisions in
      question shall be replaced by an interpretation in conformity with law
      which comes closer to effecting the parties' original intention.

    IN WITNESS WHEREOF, the parties have caused this Agreement to be executed by
their duly authorized officers effective as of the date first above written.


GILEAD SCIENCES, INC.                   ROCHE LABORATORIES INC.

By:   /s/ Mark Perry                    By: /s/ George Johnston
      --------------------------            --------------------------

Title: VP, CPO & General Counsel        Title: Assistant Secretary
      --------------------------          -----------------------

Date: Sept. 27, 1996                    Date: September 27, 1996
      --------------------------              ------------------------



                                       25