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                                                                    EXHIBIT 10.2
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                             COLLABORATION AGREEMENT

                                 by and between:

                              ARRAY BIOPHARMA INC.,
                           a Delaware corporation; and

                      VERTEX PHARMACEUTICALS INCORPORATED,
                          a Massachusetts corporation.

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                           Dated as of August 1, 2001

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                                TABLE OF CONTENTS

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ARTICLE 1         DEFINITIONS.....................................................................................1

ARTICLE 2         RESEARCH COLLABORATION..........................................................................5

         Section 2.1       Goal...................................................................................5
         Section 2.2       Targets............................................................................... 5
         Section 2.3       Research Plan..........................................................................6
         Section 2.4       General Resources and Responsibilities.................................................6
         Section 2.5       Research Collaboration Staffing........................................................7
         Section 2.6       Research Term..........................................................................8
         Section 2.7       Third Party Licenses...................................................................8
         Section 2.8       Record Maintenance.....................................................................8
         Section 2.9       Exclusivity............................................................................8
         Section 2.10      Access to Diversity Library Compounds..................................................9
         Section 2.11      Delivery...............................................................................9

ARTICLE 3         MANAGEMENT.....................................................................................10

         Section 3.1       Joint Research Committee..............................................................10
         Section 3.2       Membership............................................................................10
         Section 3.3       Meetings..............................................................................10
         Section 3.4       Minutes...............................................................................10
         Section 3.5       Decision Making.......................................................................11
         Section 3.6       Program Managers......................................................................11
         Section 3.7       Records and Reporting.................................................................11

ARTICLE 4         LICENSES.......................................................................................12

         Section 4.1       Exclusive License under Collaboration Technology......................................12
         Section 4.2       Exclusive License under Joint Technology..............................................12
         Section 4.3       Non-Exclusive License under Array Technology..........................................12
         Section 4.4       Research Use License..................................................................13
         Section 4.5       License to Vertex for Diversity Library Compounds.....................................13
         Section 4.6       No Implied Licenses...................................................................13
         Section 4.7       No Products Other than Products.......................................................13
         Section 4.8       Development and Commercialization.....................................................13

ARTICLE 5         PAYMENTS.......................................................................................14

         Section 5.1       Initial Payment.......................................................................14
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         Section 5.2       Research Collaboration Funding........................................................14
         Section 5.3       Milestones............................................................................15

ARTICLE 6         PAYMENT METHOD; BOOKS AND RECORDS..............................................................16

         Section 6.1       Payment Methods.......................................................................16
         Section 6.2       Records; Inspection...................................................................16

ARTICLE 7         DUE DILIGENCE..................................................................................17

         Section 7.1       Due Diligence.........................................................................17

ARTICLE 8         INTELLECTUAL PROPERTY..........................................................................17

         Section 8.1       Ownership of Inventions; Disclosure...................................................17
         Section 8.2       Patent Prosecution....................................................................17
         Section 8.3       Cooperation...........................................................................18
         Section 8.4       Infringement Defense..................................................................18

ARTICLE 9         CONFIDENTIALITY AND NON-USE....................................................................19

         Section 9.1       Confidential Information..............................................................19
         Section 9.2       Non-Use Obligations...................................................................20
         Section 9.3       Permitted Use and Disclosures.........................................................20
         Section 9.4       Termination of Prior Agreement........................................................20
         Section 9.5       Nondisclosure of Terms................................................................21
         Section 9.6       Publication...........................................................................21

ARTICLE 10        REPRESENTATIONS AND WARRANTIES.................................................................22

         Section 10.1      Vertex................................................................................22
         Section 10.2      Array.................................................................................22
         Section 10.3      Disclaimer............................................................................22

ARTICLE 11        INDEMNIFICATION................................................................................23

         Section 11.1      Vertex................................................................................23
         Section 11.2      Array.................................................................................23
         Section 11.3      Indemnification Procedures............................................................23

 ARTICLE 12       TERM AND TERMINATION...........................................................................24

         Section 12.1      Term..................................................................................24
         Section 12.2      Termination for Breach................................................................24
         Section 12.3      Termination for Insolvency............................................................24
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         Section 12.4      Early Termination of Research Collaboration by Vertex.................................24
         Section 12.5      Termination Upon Acquisition..........................................................25
         Section 12.6      Effect of Breach or Termination.......................................................25
         Section 12.7      Survival..............................................................................25

ARTICLE 13        MISCELLANEOUS..................................................................................26

         Section 13.1      Governing Laws........................................................................26
         Section 13.2      Waiver................................................................................26
         Section 13.3      Assignment............................................................................26
         Section 13.4      Independent Contractors...............................................................26
         Section 13.5      Compliance with Laws..................................................................26
         Section 13.6      Notices...............................................................................27
         Section 13.7      Severability..........................................................................27
         Section 13.8      Advice of Counsel.....................................................................28
         Section 13.9      Performance Warranty..................................................................28
         Section 13.10     Force Majeure.........................................................................28
         Section 13.11     Complete Agreement....................................................................28
         Section 13.12     Consultation..........................................................................28
         Section 13.13     Headings..............................................................................28
         Section 13.14     Counterparts..........................................................................28

EXHIBIT A         RESEARCH PLAN

EXHIBIT b         DIVERSITY LIBRARY COMPOUND SPECIFICATIONS
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                             COLLABORATION AGREEMENT

This COLLABORATION AGREEMENT (the "Agreement"), effective as of August 1, 2001
(the "Effective Date"), is made by and between Array BioPharma Inc., a Delaware
corporation, having a principal place of business at 1885 33rd Street, Boulder,
Colorado 80301 ("Array"), and Vertex Pharmaceuticals Incorporated, a
Massachusetts corporation, having a principal place of business at 130 Waverly
Street, Cambridge, Massachusetts 02139-4242 ("Vertex").

                                   BACKGROUND

         A. Array has developed novel and proprietary methods for the generation
of Compounds, has synthesized a Diversity Library (as defined below) and has
skills, expertise and experience in identification, generation, selection and
optimization of lead compounds to produce clinical candidates from drug
discovery programs.

         B. Vertex is a pharmaceutical company involved in the research,
development, manufacture and sale of new and useful pharmaceutical products, and
has identified biological models and assays that have the potential to be used
as the basis for drug discovery programs for specific Targets (as defined
below).

         C. Vertex and Array desire to collaborate to identify Compounds with
activity against the Targets, with the goal of delivering Compounds with desired
activity and selectivity.

         NOW, THEREFORE, for and in consideration of the covenants, conditions
and undertakings hereinafter set forth, it is agreed by and between the Parties
as follows:

                                    ARTICLE 1
                                   DEFINITIONS

         As used herein, the following terms will have the meanings set forth
below:

         1.1 "Affiliate" shall mean any corporation or other entity which is
directly or indirectly controlling, controlled by or under common control of a
Party hereto for so long as such control exists. For the purposes of this
Section 1.1, "control" shall mean the direct or indirect ownership of at least
fifty percent (50%) of the outstanding shares or other voting rights of the
subject entity having the power to vote on or direct the affairs of the entity,
or if not meeting the preceding, the maximum voting right that may be held by
the particular Party under the laws of the country where such entity exists.

         1.2 "Array Technology" shall mean Array Patent Rights, Diversity
Library Compounds, and all other technology including, but not limited to, trade
secrets, know-how, inventions,

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information (including structure-activity data) and materials, whether
patentable or not, directed to processes, formulations and/or methods
discovered, developed, owned, licensed or acquired by Array in the Field prior
to the commencement date of the Research Collaboration. Notwithstanding the
foregoing, it is understood that Array Technology shall not include any patent
or other rights to high-speed synthesis technology, methods or compound
libraries. For the avoidance of doubt, it is intended that Array Technology
shall exclude Vertex Technology, Collaboration Technology and Joint Technology.

             1.2.1 "Array Patent Rights" shall mean (i) all patents and patent
applications that claim a Diversity Library Compound, or method of use or
process for the synthesis thereof or composition-of-matter containing such
Diversity Library Compound, for which the earliest effective filing date is
prior to the Effective Date, and (ii) any divisions, continuations,
continuations-in-part, reissues, reexaminations, or extensions to the extent the
same have an earliest effective filing date prior to the date described in (i)
above, and any substitutions, confirmations, or registrations of any of the
foregoing, in each case, which is owned by Array (solely or jointly), to the
extent Array has the right to license or sublicense the same.

         1.3 "Array Researchers" shall have the meaning set forth in Section 2.5
below.

         1.4 "Diversity Library Compound Information" shall have the meaning set
forth in Section 2.11.1 below.

         1.5 "Chemical Class" shall mean those chemical entities [***].

         1.6 "Collaboration Technology" shall mean all technology including, but
not limited to, trade secrets, know-how, inventions, information (including
structure-activity data) and materials (excluding Compounds), whether patentable
or not, directed to processes, formulations and/or methods a) discovered,
developed, owned, licensed or acquired by Array (whether or not with funding
support by Vertex) arising out of or in connection with the conduct of the
Research Collaboration; or (b) discovered, developed, owned, licensed or
acquired by Array Researcher(s) funded by Vertex in the course of performing
activities under the Research Plan. For the avoidance of doubt, it is intended
that Collaboration Technology shall exclude Vertex Technology, Array Technology
and Joint Technology.

         1.7 "Compound" shall mean any chemical entity synthesized by Array and
disclosed to Vertex in the course of performing or in connection with the
Research Collaboration that is identified as having that level of activity
against a Target in the applicable assay as set forth in the Research Plan. For
the purposes hereof, a prodrug shall also constitute a "Compound", provided that
the active component of such prodrug has the level of activity specified in the
Research Plan. Notwithstanding the foregoing, it is understood and agreed that
no Diversity Library Compound shall be deemed a Compound. The Parties agree that
the Research Plan shall specify an enzymatic inhibition activity level no
greater than [***].

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         1.8 "Consumer Price Index" or "CPI" means the Consumer Price Index, All
Urban Consumers, as published by the U.S. Bureau of Labor Statistics.

         1.9 "Diversity Library" shall mean the collection of chemical entities
that Array makes available on a non-exclusive basis to Third Parties contained
within 96-well plates. The Diversity Library shall contain between [***] and
[***] chemical entities.

         1.10 "Diversity Library Compound" shall mean any chemical entity that
is contained in the Diversity Library.

         1.11 "Field" shall mean the discovery, development and
commercialization of small molecules for the therapeutic or prophylactic
treatment of diseases and conditions in humans, wherein the mechanism of action
of such small molecules is to modulate the activity of a Target.

         1.12 "First Commercial Sale" shall mean, with respect to each Product,
the first bona fide FDA-approved commercial sale of such Product in the United
States by or under authority of Vertex, its Affiliates or Licensees.

         1.13 "FTE" shall mean a full-time person dedicated to the Research
Collaboration, or in the case of less than a full-time, dedicated person, a
full-time, equivalent person year, based upon a total of [***] hours per year of
work in connection with the Research Collaboration.

         1.14 "Inactive Chemical Entity" shall mean a chemical entity, (other
than a Compound, or a chemical entity in the Chemical Class, or a Diversity
Library Compound) synthesized and screened by Array in the course of performing,
or in connection with, the Research Collaboration.

         1.15 "JRC" or "Joint Research Committee" shall have the meaning set
forth in Section 3.1.

         1.16 "Joint Technology" shall mean all technology including, but not
limited to, trade secrets, know-how, inventions, information (including
structure-activity data) and materials (excluding Compounds), whether patentable
or not, directed to products, processes, formulations and/or methods that are
developed by Array using Vertex Technology or are discovered, developed,
licensed or acquired jointly by Array and Vertex in performance of the Research
Collaboration or thereafter until termination of the Agreement. For the
avoidance of doubt, it is intended that Joint Technology shall exclude Vertex
Technology, Array Technology and Collaboration Technology.

         1.17 "Licensed Technology" shall mean, collectively, Collaboration
Technology, Joint Technology, and Array Technology licensed to Vertex under this
Agreement.

         1.18 "Licensee" shall mean, with respect to a particular Product, a
Third Party to whom Vertex has granted a license or other right under the
Licensed Technology to make and sell such Product. As used in this Agreement,
"Licensee" shall also include a Third Party to whom Vertex has granted the right
to distribute such Product, provided that such Third Party has responsibility
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marketing and promotion of such Product within the field or territory for
which such distribution rights are granted.

         1.19 "NDA" shall mean a New Drug Application, as defined in the U.S.
Food, Drug and Cosmetic Act and the regulations promulgated thereunder, or any
corresponding foreign application, registration or certification.

         1.20 "Net Sales" shall mean the gross invoice price by Vertex or its
Affiliates or Licensees, as the case may be, for all Products sold by Vertex,
its Affiliates or Licensees ("Selling Party"), under this Agreement in arm's
length sales to Third Parties less deductions allowed to the Third Party
customer by the Selling Party on such sales for: (a) trade, quantity, and cash
discounts; (b) credits, rebates (including those to managed-care entities and
government agencies), and allowances or credits to customers on account of
rejection or returns (including, but not limited to, wholesaler and retailer
returns) or on account of retroactive price reductions affecting such Product;
(c) freight, postage and duties; and (d) sales and excise taxes, other
consumption taxes, customs duties and compulsory payments to governmental
authorities and any other governmental charges imposed upon the sale of such
Product to Third Parties. In addition, the Selling Party may exclude from Net
Sales a reasonable provision for uncollectible accounts, to the extent such
reserve is determined in accordance with generally accepted accounting
standards, consistently applied across all product lines of the particular
Party, until such amounts are actually collected. Notwithstanding the foregoing,
Net Sales shall not include sales among Vertex, its Affiliates and Licensees for
resale, provided that such resale shall be included within Net Sales.

         1.21 "Party" or "Parties" shall mean, respectively, Array or Vertex
individually, or Array and Vertex collectively.

         1.22 "Phase IIb" shall have the meaning attributed to such term in 21
CFR 312.21.

         1.23 "Phase III" shall mean human clinical trials, the principal
purpose of which is to establish safety and efficacy of one or more particular
doses in patients being studied, and which will (or are intended to) satisfy the
requirements of a pivotal trial for purposes of obtaining approval of a Product
in a country by the health regulatory authority in such country to market such
Product for an application in the Field, and more specifically, shall have the
meaning attributed to such term in 21 CFR 312.21.

         1.24 "Product" shall mean any diagnostic, therapeutic or prophylactic
product for use in the Field, incorporating as an active ingredient at least one
of the following (i) a Compound, or (ii) a chemical entity in the same Chemical
Class as a Compound. For the avoidance of doubt, a Product will be considered a
single Product and not a separate Product, even if multiple marketing approvals
are or would be required by the FDA (or the relevant competent authority), if
the multiple marketing approvals are solely due to changes to or variations of
(a) the inactive ingredient(s) and/or concentration of the active ingredient(s),
(b) the method of delivery (e.g., tabular versus injectable forms, modified
dosage forms, treatment modalities), and/or (c) prodrug moieties.

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         1.25 "Research Collaboration" shall mean the research activities
undertaken by the Parties pursuant to this Agreement.

         1.26 "Research Plan" shall mean the written research plan, adopted by
the Parties promptly after the Effective Date, governing the joint effort of the
Parties in conducting the Research Collaboration in the Field. The Research Plan
may be amended from time to time by the Joint Research Committee as it deems
necessary or appropriate and shall specify the Array personnel to conduct
activities with respect to the Research Collaboration, such personnel to be
proposed by Array. The initial Research Plan shall be attached hereto as
Exhibit A.

         1.27 "Research Term" shall mean the term of the Research Collaboration,
as provided in Section 2.6 below.

         1.28 "Research Year" shall mean a twelve (12) month period during the
term of the Research Collaboration. The first Research Year hereunder shall be
deemed to have commenced on the Effective Date.

         1.29 "Target(s)" and "Substitute Targets" shall mean those molecular
targets which the parties agree are the subject of the Research Collaboration
pursuant to Section 2.2 below.

         1.30 "Third Party" shall mean any person or entity other than Array and
Vertex, and their respective Affiliates.

         1.31 "Vertex Technology" shall mean all technology including, but not
limited to, trade secrets, know-how, inventions and information (including test
data, protocols and screening methodology), and materials, whether patentable or
not, directed to products, processes, formulations and/or methods that Vertex
discovers, develops, identifies, licenses or acquires independently of Array
(i.e., without the use of the Confidential Information of Array), and Compounds,
pharmaceutical compositions containing a Compound, chemical entities in a
Chemical Class, or the use of a Compound or a composition containing a Compound
for therapeutic purposes. For the avoidance of doubt, it is intended that Vertex
Technology shall exclude Array Technology, Collaboration Technology and Joint
Technology.

                                    ARTICLE 2
                             RESEARCH COLLABORATION

         2.1 Goal. The goal of the Research Collaboration is to identify
Compounds that will serve as lead classes against the Targets.

         2.2 Targets.

             2.2.1 General. The Research Collaboration shall be focused on
identifying chemical entities that have activity against the following two (2)
phosphatase Targets: [***].

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             2.2.2 Abandonment and Substitution of Targets. The JRC may decide
to discontinue research activities with respect to one or more Targets (each a
"De-Selected Target"). In such event, any Compound directed to a De-Selected
Target and any chemical entity in the same Chemical Class as such Compound
directed to a De-Selected Target shall remain subject to this Agreement;
provided, however, that if during the Research Term research activities are
discontinued with respect to a particular De-Selected Target because Vertex
elects to cease all research and development activities with respect to such
De-Selected Target (an "Abandoned Target"), then (i) Vertex shall so notify
Array in writing, and (ii) Arrays' obligations under Section 2.9 below with
respect to such Abandoned Target shall terminate [***] after the effective date
of the written notice to discontinue research activities with respect to such
Abandoned Target. No chemical entity synthesized by Array directed to such
De-Selected Target after the effective date of the written notice to discontinue
research activities with respect to such De-Selected Target shall be deemed to
be a Compound or Inactive Chemical Entity under this Agreement. In the event
that research activities are discontinued with respect to any De-Selected Target
pursuant to this Section 2.2.2, then Vertex may substitute, upon consultation
with the JRC and mutual agreement of the Parties, such agreement not to be
unreasonably withheld or delayed, another target in its place as a Target for
purposes of this Agreement (a "Substitute Target"). The Substitute Target(s) may
be a phosphatase Target, or a Target outside the phosphatase class of enzymes.
Such Substitute Target(s) shall be deemed to be a Target for the purposes of
this Agreement upon the consent of Array. Array shall not be obligated to
substitute more than two (2) such Substitute Targets during the Research Term,
except as the parties may otherwise agree in writing.

             2.2.3 Additional Targets. Upon request of Vertex and subject to the
consent of Array, such consent not to be unreasonably withheld, the Research
Collaboration may be expanded to include additional Targets in excess of the
number set forth in Section 2.2.1.

         2.3 Research Plan. The Research Collaboration shall be carried out in
accordance with a mutually agreed upon written Research Plan attached hereto as
Exhibit A which shall establish specific research objectives and the research
tasks to be performed and resources to be provided by Array. The Research Plan
shall, among other things, establish: (i) the scope of the research activities
which will be performed; (ii) the research objectives and work plan activities;
(iii) specific screening assays for identifying and testing the activity of
chemical entities against each Target; and (iv) the criteria for determining
when a chemical entity shall be deemed a Compound. The JRC shall review the
Research Plan on an ongoing basis and may make changes thereto as the JRC
approves.

         2.4 General Resources and Responsibilities.

             2.4.1 Array Responsibilities. During the Research Term, Array shall
make the following resources available in connection with the Research
Collaboration activities to be performed by Array, as specified in the Research
Plan:

             (a)  Screening of compounds against Targets;

             (b)  Initial drug discovery, including lead generation and lead
                  optimization;

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             (c)  in vitro and ex vivo metabolite profiling;

             (d)  Medicinal and combinatorial chemistry; and

             (e)  All materials, equipment and facilities used for the
                  preparation and testing of Compounds, and the handling and
                  disposal of any waste material generated by Array during the
                  performance of the Research Collaboration. Array covenants
                  that the materials, equipment and facilities to be used by
                  Array under this Agreement shall be of the same quality as
                  Array in its experience and best scientific judgment uses in
                  its own research of similar nature.

             In performing its obligations under the Research Collaboration,
Array shall use such of its available Diversity Library Compounds as Array
reasonably deems necessary or useful for lead generation. During the Research
Term, Array shall provide to Vertex such Array Technology as may be reasonably
necessary for Vertex to carry out research activities in furtherance of the
Research Collaboration.

             During the term of the Research Collaboration and thereafter until
termination of the Agreement, Array agrees that, as reasonably requested by
Vertex, at Vertex's expense, appropriate individuals shall be available to
assist and consult with Vertex in connection with the Licensed Technology. Such
assistance and consultation by Array may be by means of personal visits,
correspondence or telephone discussions.

             2.4.2 Vertex Responsibilities. During the Research Term, Vertex
shall have the right, but not the obligation, to carry out research activities
with respect to the Targets that Vertex deems advisable, in its sole discretion,
to promote the objectives of this Agreement. During the Research Term, Vertex
shall provide to Array such Vertex Technology as may be reasonably necessary for
Array to carry out research activities in furtherance of the Research
Collaboration.

         2.5 Research Collaboration Staffing. Subject to Vertex funding the
Research Collaboration pursuant to Section 5.2 Array shall devote the following
number of FTEs to the conduct of the Research Collaboration by or during the
following periods:

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             End of first six months                     [***] FTEs

             End of first twelve months through          [***] FTEs
             the end of the Research Term
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             The Array research staff conducting the Research Collaboration (the
"Array Researchers") shall include a dedicated team leader [***]. At least [***]
of the Array Researchers will [***] and Vertex shall have the right to review
the qualifications of all Array Researchers.

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Array shall employ an optimal combination of experience and training in the
Field in selecting members for the Array Researchers. Vertex and Array
acknowledge the importance of having personnel devoted full-time to work in the
Research Collaboration; accordingly, in order to maximize the effective conduct
of the Research Collaboration, Array will use reasonable best efforts to
maximize the continuity of Array Researchers conducting the Research
Collaboration, and in all events shall immediately report to Vertex any changes
in Array Researchers personnel. Additionally, each Array Researcher who is
engaged in chemistry shall, at minimum, work as [***] FTE under the Research
Collaboration.

         2.6 Research Term. The Research Term shall commence on the Effective
Date and shall end upon the earlier to occur of (i) the [***] of the Effective
Date, or (ii) the termination of this Agreement.

         2.7 Third Party Licenses. In the event that the Parties agree to
acquire additional technologies from a Third Party specifically for use in the
conduct of the Research Collaboration in the Field, Vertex will be responsible
for the payment of any amounts due to the Third Party for the license of
intellectual property which directly applies to any Target, and the costs of
negotiating, preparing and executing any such license.

         2.8 Record Maintenance. Array shall maintain records of the Research
Collaboration (or cause such records to be maintained) in sufficient detail and
in good scientific manner as will properly reflect all work done and results
achieved in the performance of the Research Collaboration (including all data in
the form required under any applicable governmental regulations and as directed
by the JRC). Such records will be dated and witnessed and otherwise suitable for
patent purposes in accordance with generally acceptable industry standards of
all work performed and data developed for or on Vertex's behalf during the
Research Collaboration.

         2.9 Exclusivity. Except as set forth herein, during the period set
forth in this Section 2.9, Array shall not knowingly conduct, participate in, or
fund, directly or indirectly, alone or with a Third Party, discovery research
specifically directed to the Field (the "Exclusivity Period"). Except as set
forth in Section 2.2.2 above, Array's obligations under this Section 2.9 shall
commence on the Effective Date and shall continue until (i) the [***] of the end
of the Research Term, or (ii) with respect to Targets for which Vertex is
developing a Product, for so long as Vertex is pursuing diligent research and/or
development of such a Product, but in no event later than the [***] of the end
of the Research Term. Notwithstanding the above, in the event of a Change of
Control of Array, the provisions of this Section 2.9 shall not apply to the
surviving entity. For purposes of this Section 2.9, a "Change of Control" shall
mean the merger, consolidation, sale of substantially all of its assets or
similar transaction or series of transactions, as a result of which Array's
shareholders before such transaction or series of transactions own less than
fifty percent (50%) of the total number of voting securities of the surviving
entity immediately after such transaction or series of transactions.
Notwithstanding the foregoing, if as a result of any such Change of Control,
Array exists as a wholly owned subsidiary of a parent, then the provisions of
this Section 2.9 shall continue to apply to Array, but not to such parent.

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         2.10 Access to Diversity Library Compounds. On or before the first
anniversary of the Effective Date, Vertex shall have the right to select up to
[***] of the Diversity Library Compounds existing as of the first anniversary of
the Effective Date (the "Available Diversity Library Compounds") on a plate by
plate basis. Within thirty (30) days after the Effective Date, Array shall
provide Vertex with a complete list of available Diversity Library Compounds and
their chemical structures. Thereafter, prior to the first anniversary of the
Effective Date, updates of the list of the available Diversity Library Compounds
shall be provided to Vertex on a quarterly basis, and Vertex shall advise Array
of its selection(s) of available chemical entities within thirty (30) days of
receipt of each such update. Upon receipt of written notice of Vertex's
selection, Array shall deliver such Diversity Library Compounds to Vertex in
accordance with this Section 2.10. Based upon the availability of such Diversity
Library Compounds, Array shall deliver to Vertex a [***] of each Diversity
Library Compound, and each Diversity Library Compound shall conform to the
specifications set forth in Exhibit B. In the event Array is unable to deliver
the full [***] of the Available Diversity Library Compounds due to the failure
of such Diversity Library Compounds to conform to the specifications set forth
in Exhibit B, Vertex shall have the option to select additional Diversity
Library Compounds during the term of this Agreement, so that the total number of
Diversity Library Compounds delivered by Array to Vertex equal [***] of the
Available Diversity Library Compounds. Vertex shall have the right to obtain
from Array additional amounts of the selected Diversity Library Compounds, upon
commercially reasonable terms.

         2.11 Delivery.

              2.11.1 Diversity Library. Array shall use good faith efforts to
deliver the Diversity Library Compounds in accordance with a schedule mutually
agreed upon by the Parties. The Diversity Library Compounds shall be delivered
F.O.B. Vertex's facility at the address set forth above (or such other address
as Vertex may specify in writing prior to the shipping date). The carrier shall
be paid by Vertex, and shall be selected by agreement between Array and Vertex,
provided that in the event no such agreement is reached Array shall select the
carrier. Together with each Diversity Library Compound delivered hereunder,
Array shall make available to Vertex the following information for the Diversity
Library Compounds: [***] (collectively, the "Diversity Library Compound
Information").

             2.11.2 Compounds and Inactive Chemical Entities. Array shall
transfer to Vertex (or a Third Party designated by Vertex) all Compounds and
Inactive Chemical Entities, in the amount and purity set forth in this Section
2.11.2, in the Research Plan or as otherwise agreed upon by the Parties.
Together with each Compound and Inactive Chemical Entity, Array shall provide to
Vertex corresponding information relating to its preparation, analytical
properties and biological activity. Vertex shall have clear title to the
physical samples of Compounds and Inactive Chemical Entities it receives, and
except as otherwise provided in this Agreement, Vertex shall be free to use the
Compounds without further obligation to Array. Array shall deliver to Vertex a
minimum of [***] mg of each Compound, and a minimum of [***] mg of each Inactive
Chemical Entities which shall conform to the specifications set forth in the
Research Plan.

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -9-
<PAGE>

             Array shall use its best efforts to ensure that the Compounds
delivered hereunder have a purity of at least [***] by LCMS, and that the
Inactive Chemical Entities delivered hereunder have a purity level as determined
by the JRC, but in no event shall the purity level of the Inactive Chemical
Entities be less than [***] by LCMS. Array shall use commercially reasonable
efforts to deliver the Compounds and Inactive Chemical Entities promptly after
they are screened, but in any event not less than on a quarterly basis, or in
accordance with a schedule mutually agreed upon by the Parties. The Compounds
and Inactive Chemical Entities shall be delivered F.O.B. Vertex's facility at
the address set forth above (or such other address as Vertex may specify in
writing prior to the shipping date). The carrier shall be paid by Vertex, and
shall be selected by agreement between Array and Vertex, provided that in the
event no such agreement is reached Array shall select the carrier. Upon
termination or expiration of the Research Collaboration, Array shall deliver to
Vertex any unused Compounds synthesized by Array during the term of the Research
Collaboration.

                                    ARTICLE 3
                                   MANAGEMENT

         3.1 Joint Research Committee. As soon as practicable after the
Effective Date, Vertex and Array will establish a committee (the "Joint Research
Committee" or "JRC") to oversee, review and recommend direction of the Research
Collaboration. The responsibilities of the Joint Research Committee shall
include, among other things: (i) monitoring and reporting research progress and
ensuring open and frequent exchange between the Parties regarding Research
Collaboration activities; (ii) coordination of all discovery and optimization
programs under the Research Collaboration; and (iii) amending as necessary the
criteria for the selection of Compounds for each Target.

         3.2 Membership. The JRC shall include two (2) representatives of each
of Vertex and Array, each Party's members selected by that Party. Array and
Vertex may each replace its JRC representatives at any time, upon written notice
to the other Party. From time to time, the JRC may establish subcommittees, to
oversee particular projects or activities, and such subcommittees will be
constituted as the JRC agrees.

         3.3 Meetings. During the Research Term, the JRC shall meet at least
quarterly, or as agreed by the Parties, at such locations as the Parties agree,
and will otherwise communicate regularly by telephone, electronic mail,
facsimile and/or video conference. With the consent of the Parties, other
representatives of Array or Vertex may attend JRC meetings as nonvoting
observers. Each Party shall be responsible for all of its own expenses
associated with attendance of such meetings. The first meeting of the JRC shall
occur within forty-five (45) days after the Effective Date.

         3.4 Minutes. The JRC and/or a designated clerk shall keep accurate
minutes of its deliberations which shall record all proposed decisions and all
actions recommended or taken. The Secretary of the JRC (as appointed by the
members of the JRC) and/or a designated clerk shall be responsible for the
preparation of draft minutes. Draft minutes shall be sent to all members of the

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -10-
<PAGE>

JRC after each meeting and shall be approved, if appropriate, at the next
meeting. All records of the JRC shall at all times be available to both Array
and Vertex.

         3.5 Decision Making. Decisions of the JRC shall be made by unanimous
agreement. In the event that unanimity is not achieved within the JRC, the
matter will be referred to Array's Chief Scientific Officer and Vertex's Vice
President of Research, U.S., who shall promptly meet and endeavor in good faith
to resolve such matter in a timely manner. If such individuals cannot resolve
such dispute, then, other than with respect to [***]; provided, however, that
notwithstanding the foregoing, Array shall not be obligated, as a result of
[***], to violate any obligation or agreement it may have with any Third Party.

         3.6 Program Managers. Array shall appoint [***] as the Array Program
Manager and Vertex shall appoint [***] as the Vertex Program Manager. Each
Program Manager shall be the principal point of contact between the Parties.
Each Party may change its Program Manager by giving [***] days' written notice
to the other Party.

         3.7 Records and Reporting.

             3.7.1 Array shall keep Vertex fully informed of the progress of the
Research Collaboration by providing summary reports ("Summary Reports") to the
Vertex Program Manager and the JRC from time to time, but no less frequently
than on a quarterly basis. Each Summary Report shall include at least the
following: (i) [***] conducting the Research Collaboration, (ii) an [***] to the
Research Collaboration, (iii) a description in reasonable detail of the
activities, including the work conducted and data generated by Array Researchers
in support of the Research Collaboration and (iv) a description in reasonable
detail of all Licensed Technology generated by Array, specifically including,
but not limited to, Compound(s), Inactive Chemical Entities, all assay data
generated with any such Compound(s), methods and processes for the preparation
of any such Compound(s), synthetic intermediates thereof, and methods and
processes for the preparation of synthetic intermediates and raw materials
useful in the preparation of any such Compound(s).

             3.7.2 Array shall ensure that its key personnel involved with the
Research Collaboration and the Array Program Manager are reasonably available
for telephone and face-to-face discussions with Vertex's personnel as may be
agreed upon by the Parties. Additionally, the Array Program Manager shall be
reasonably available for bi-weekly conference calls with the Vertex Program
Manager or other duly authorized representative of Vertex to discuss the
Research Plan and to report the activities, including the work conducted and
data generated by Array Researchers in support of the Research Collaboration.
The Array Program Manager (or the Array Program Manager's authorized appointee)
shall be responsible for, and keep, accurate records of the bi-weekly conference
calls which shall record all recommended material decisions and material
actions. All records of the bi-weekly conference calls shall at all times be
available to both Array and Vertex. Except as otherwise provided in Section 3.3
and in this Section 3.7.2, if Vertex requests Array personnel to attend any
further meetings other than those on Array premises, Array shall be reimbursed
for reasonable travel expenses incurred by Array personnel attending such
meetings.

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -11-
<PAGE>

             3.7.3 Upon completion of the Research Collaboration, Array shall
provide Vertex with [***] technical information and supporting documentation
generated in the course of the Research Collaboration and necessary for the
manufacturing process and development of the Compound(s) and Inactive Chemical
Entities in sufficient detail to allow Vertex to reproduce such process. Array
shall promptly provide Vertex with copies of all technical information, data,
records and supporting documentation reasonably requested by Vertex relating to
the Research Collaboration, subject to the provisions of Article 9, including
without limitation Compound information such as analytical and structure
determination information, purity and physical characteristics at the same time
as the Compounds and Inactive Chemical Entities are provided to Vertex.

                                    ARTICLE 4
                                    LICENSES

         4.1 Exclusive License under Collaboration Technology. Array hereby
grants to Vertex a royalty-free, exclusive world-wide license, with the right to
sublicense under Collaboration Technology to make, have made, use, sell, lease,
offer to sell or lease, import, export or otherwise transfer physical possession
of or title in the Compound(s) and/or Product(s).

         4.2 Exclusive License under Joint Technology. Array hereby grants to
Vertex a royalty-free, exclusive world-wide license, with the right to
sublicense under its rights to the Joint Technology to make, have made, use,
sell, lease, offer to sell or lease, import, export or otherwise transfer
physical possession of or title in the Compound(s) and/or Product(s).

         4.3 Non-Exclusive License under Array Technology.

             4.3.1 Array hereby grants to Vertex a royalty-free, non-exclusive
world-wide license, with the right to sublicense, under Array Technology, solely
to make, have made, use, sell, lease, offer to sell or lease, import, export or
otherwise transfer physical possession of or title in (i) Product(s) in the
Field, and (ii) Compound(s) inside the Field or outside the Field. The license
granted under this Section 4.3.1 shall include the right to grant sublicenses to
Vertex's collaborators.

             4.3.2 Array hereby grants to Vertex a royalty-free, non-exclusive
world-wide license, under Array Improvements, solely to make, have made, use,
sell, lease, offer to sell or lease, import, export or otherwise transfer
physical possession of or title in Compounds [***] as a Compound in the Field.
The license granted under this Section 4.3.2 shall include the right to grant
sublicenses to Vertex's collaborators, and shall be subject to any pre-existing
licenses granted to any Third Party by Array. For the purposes of this Section
4.3.2, "Array Improvements" shall mean any improvements made to the Licensed
Technology after expiration of the Research Term.

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -12-
<PAGE>

         4.4 Research Use Licenses. Array hereby grants to Vertex a perpetual,
compensation-free, non-exclusive license, without the right to sublicense, under
Licensed Technology to make, have made and use Compounds to make, have made and
use any Inactive Chemical Entity for Vertex's own internal research purposes (on
its own or through a Third Party on behalf, or under the authority, of Vertex).

         4.5 License to Vertex for Diversity Library Compounds. Array hereby
grants to Vertex a non-exclusive right and license, under the applicable
Licensed Technology, to make, have made and use the Diversity Library Compounds
physically transferred pursuant to Section 2.10, and corresponding Diversity
Library Compound Information for its own internal research purposes. The license
granted under this Section 4.5 shall not include the right to grant or authorize
sublicense.

         4.6 No Implied Licenses. Only the licenses granted pursuant to the
express terms of this Agreement shall be of any legal force or effect. No other
license or rights, including without limitation any license or right to Array
Technology or Vertex Technology, shall be created by implication, estoppel or
otherwise.

         4.7 No Products Other than Products. Except as otherwise agreed in
writing or specifically provided in the terms of this Agreement, neither Vertex
nor its Affiliates nor Licensees shall, directly or indirectly commercialize for
use in the Field any [***], other than as a Product in accordance with this
Agreement.

         4.8 Development and Commercialization.

             4.8.1 Post Research Collaboration Activities; Product Development.
Vertex shall have sole and full control, authority, discretion and
responsibility for conducting, funding and pursuing all aspects of clinical
development, regulatory, manufacturing and commercialization of Compounds in the
Field, either on its own, through a sublicensee or through a Third Party on
behalf of or under the authority of Vertex or its sublicensee. Notwithstanding
anything to the contrary in this Agreement, Array shall have no rights and will
have no involvement with respect to any such clinical development, regulatory,
manufacturing and commercialization. In exercising such rights, Vertex shall
have the exclusive right, and may select in its sole discretion trademarks for
such Products, and Vertex shall own all right, title or interest in such
trademarks (subject to any pre-existing rights of Array or Third Parties).

             4.8.2 Regulatory Filings and Governmental Approvals. Vertex shall
have sole and full control, authority, discretion and responsibility to prepare,
file and own all right, title and interest in regulatory filings and
governmental approvals relating to the Compounds, either on its own, through a
sublicensee or by a Third Party on behalf of or under the authority of Vertex or
its sublicensee. Notwithstanding anything to the contrary in this Agreement,
Array shall have no rights with respect to the preparation, filing and ownership
of any such regulatory filings and governmental approvals, but will, upon
Vertex's reasonable request, assist Vertex in the preparation of such regulatory
filings (at Vertex's expense).

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -13-
<PAGE>

                                    ARTICLE 5
                                    PAYMENTS

         5.1 Initial Payment. Vertex shall pay to Array an initial fee [***]
U.S. dollars [***] within [***] days after the Effective Date and upon receipt
of invoice by Vertex, which amount shall be non-refundable and non-creditable
against any other amounts due Array under this Agreement.

         5.2 Research Collaboration Funding.

             5.2.1 FTEs. Vertex agrees to pay Array research funding for the
conduct of the Research Collaboration in an amount equal to the number of Array
FTEs called for in Section 2.5 or the Research Plan for the applicable quarter
multiplied by the Array FTE Rate (as defined below). The number of FTEs for
particular periods within the Research Term is set forth in Section 2.5, as may
be modified by the Research Plan. The "Array FTE Rate" shall be equal to [***]
U.S. dollars [***] per FTE per Research Year (the "Funding Commitment"). During
[***], the FTE Rate [***]. [***], the FTE Rate shall increase no more than [***]
by the percentage increase, if any, in the Consumer Price Index for all Urban
Consumers, as published by the U.S. Department of Labor, Bureau of Statistics,
since the Effective Date or the last adjustment hereunder, whichever is later.
The payments subject to this Section 5.2.1 shall be paid in quarterly
installments, in advance,. The initial payment shall be made within [***] days
of the date Array FTEs are first deployed in accordance with the Research Plan
and upon receipt of invoice by Vertex. Subsequent payments shall be made on or
before the first day of each calendar quarter thereafter within [***] days after
receipt of an invoice by Vertex which sets forth the actual number of Array
Researchers FTEs estimated for the upcoming quarter. Such payments are
non-refundable; provided, however, that if in the event that for any quarter of
the Research Term the number of Array Researcher FTEs funded by Vertex for such
quarter shall exceed the actual number of Array Researcher FTEs devoted to the
conduct of the Research Collaboration in such quarter, Vertex shall be entitled
to credit any such excess against the Funding Commitment in the next quarter. If
upon termination or expiration of the Research Term, the aggregate number of
Array Researcher FTEs funded by Vertex exceeds the aggregate number of Array
Researcher FTEs actually devoted to the conduct of the Research Collaboration,
Array shall promptly reimburse Vertex for such excess at the applicable FTE
Rate. Array shall keep accurate records and books of accounts containing all
data reasonably required for the calculation and verification of FTEs employed
by Array in the Research Collaboration.

             5.2.2 Non-FTE Costs. Non-FTE Costs and resource requirements (e.g.,
analytical, computational support, and the cost of storage, handling,
transportation and disposal of chemical synthesis of products generated by
Array) associated with the Research Collaboration shall be borne by Array,
except that Vertex agrees to reimburse Array for any extraordinary chemical
costs incurred by Array in accordance with the Research Plan and as otherwise
pre-approved by Vertex. Array shall not be obligated to incur any extraordinary
non-FTE costs in connection with this Research Collaboration.

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -14-
<PAGE>

             5.2.3 No Withholding. All amounts paid by Vertex to Array pursuant
to Sections 5.2.1 and 5.2.2 shall be made without withholding for taxes or any
other charge.

         5.3 Milestones.

             5.3.1 Milestone Payments Based on Clinical Events. Vertex shall pay
to Array the following amounts within [***] days following the first achievement
by Vertex or its Affiliates, Licensees or other designees, as the case may be,
of each of the following milestones with respect to each Target:

<TABLE>
<CAPTION>
CLINICAL EVENTS MILESTONES                                                        PAYMENT AMOUNT
<S>                                                                               <C>
1. [***]                                                                          $[***]

2. [***]                                                                          $[***]

3. [***]                                                                          $[***]

4. [***]                                                                          $[***]
</TABLE>

Vertex shall not be obligated to pay any Clinical Events Milestone payments
under this Section 5.3.1 more than [***] with respect to each Target, regardless
of the number of Compounds that achieve a particular Clinical Milestone event.

             5.3.2 Milestone Payments Based on Net Sales. During each full
calendar year following the First Commercial Sale of a Product, Vertex shall pay
to Array the following amounts within [***] days of the end of each calendar
quarter following the achievement of each of the following Net Sales milestones
with respect to each Product:

<TABLE>
<CAPTION>
NET SALES MILESTONE                                                               PAYMENT AMOUNT
<S>                                                                               <C>
1. Net Sales in the U.S. exceed [***]                                             $[***]

2. Net Sales in the U.S. exceed [***]                                             $[***]

3. Net Sales in the U.S. exceed [***]                                             $[***]

4. Net Sales in the U.S. exceed [***]                                             $[***]

5. Net Sales in the U.S. exceed [***]                                             $[***]

</TABLE>

                   (a) Net Sales of a particular Product shall be based on the
aggregate sales of such Product by Vertex, its Affiliates and Licenses.

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -15-
<PAGE>

                   (b) Each of the milestone payments set forth in this Section
5.3.2 are [***] for each [***]. By way of example, in a given calendar year
within [***] years of the First Commercial Sale of a Product, if Net Sales
related to such Product were [***] million, Vertex would be obligated to pay
Array a milestone payment of [***], and if Net Sales related to such Product
were [***] million, Vertex would be obligated to pay Array a milestone payment
of [***].

                   (c) Vertex's obligation to make the milestone payments due
under this Section 5.3.2 shall commence, on a [***], on the first day of the
first calendar year following the First Commercial Sale of such Product, and
shall continue, on a [***], until the end of the [***] following the First
Commercial Sale of such Product.

                                    ARTICLE 6
                        PAYMENT METHOD; BOOKS AND RECORDS

         6.1 Payment Method. All payments due under this Agreement shall be made
from a bank located in the United States by bank wire transfer in immediately
available funds to a bank account designated by Array. All payments hereunder
shall be made in U.S. dollars. In the event that the due date of any payment
subject to Article 5 hereof is a Saturday, Sunday or national holiday, such
payment may be paid on the following business day. Any payments that are not
paid within [***] days after the date such payments are due under this Agreement
shall bear interest to the extent permitted by applicable law at the prime rate
as reported by the Chase Manhattan Bank, New York, New York, on the date such
payment is due, plus an additional [***], calculated on the number of days such
payment is delinquent.

         6.2 Records; Inspection. Vertex and its Affiliates and Licensees shall
keep complete, true and accurate books of account and records for the purpose of
determining the milestone amounts payable under this Agreement. Such books and
records shall be kept at the principal place of business of such party, as the
case may be, for at least three (3) years following the end of the calendar
quarter to which they pertain. Such records will be open for inspection during
such three (3) year period by a public accounting firm to whom Vertex has no
reasonable objection, solely for the purpose of verifying milestone statements
hereunder. Such inspections may be made no more than once each calendar year, at
reasonable times and on reasonable notice. Inspections conducted under this
Section 6.2 shall be at the expense of Array, unless a variation or error
producing an increase in payment to Array in excess of [***] for any period
covered by the inspection is established in the course of any such inspection,
whereupon all reasonable costs relating to the inspection for such period and
any unpaid amounts that are discovered will be paid promptly by Vertex to Array
together with interest thereon from the date such payments were due at the
lesser of the prime rate as reported by the Chase Manhattan Bank, New York, New
York, plus an additional [***] or the maximum rate permitted by law. The
interest available to Array pursuant to this Section 6.2 shall in no way limit
any other remedies available to Array.

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -16-
<PAGE>

                                    ARTICLE 7
                                  DUE DILIGENCE

         7.1 Due Diligence. For each Compound and Product to which Vertex
retains rights under this Agreement, Vertex shall use commercially reasonable
efforts to develop and commercialize such Compounds and Products, and to obtain
the optimum commercial return for each Compound, for the development,
commercialization and marketing of pharmaceutical products of similar commercial
value potential.

                                    ARTICLE 8
                              INTELLECTUAL PROPERTY

         8.1 Ownership of Inventions; Disclosure.

             8.1.1 General. Subject to Section 8.1.2 below, title and interest
to all Vertex Technology shall be owned by Vertex; title and interest to all
Array Technology shall be owned by Array; title and interest to all
Collaboration Technology and all patent rights and other intellectual property
rights related thereto shall be owned by Array; title and interest to all Joint
Technology shall be jointly owned by Array and Vertex. Except as expressly
provided in this Agreement, it is understood that Vertex shall have no
obligation to account to Array for profits or to obtain any approval of Array to
license or exploit any jointly owned invention, by reason of joint ownership of
any invention or other intellectual property. Inventorship of inventions and
other intellectual property conceived and/or reduced to practice pursuant to
this Agreement shall be determined in accordance with the patent laws of the
United States. Each Party shall promptly disclose to the other any inventions
made in connection with this Agreement.

             8.1.2 Compositions; Uses. [***] and other intellectual property
made by personnel of Vertex or Array (solely or jointly) in the course of
performing, or in connection with, the Research Collaboration comprising (i)
[***], (ii) [***], or (iii) [***]. Array [***]. It is understood and agreed that
[***] under this Section 8.1.2 shall be [***], and shall [***].

         8.2 Patent Prosecution.

             8.2.1 Jointly Owned Inventions. Vertex shall have the first right
to control, at Vertex's expense, the preparation, filing, prosecution and
maintenance of patents and patent applications directed to Joint Technology, and
conducting any interferences, re-examinations, reissues and oppositions with
respect thereto. Vertex may elect, upon [***] prior notice to Array, to
discontinue prosecution of any such patent applications and/or not to file or
conduct any further activities with respect to such patent applications or
patents. In the event Vertex declines to file or, having filed, fails to further
prosecute or maintain any such patent applications or patents, or conduct any
proceedings including, but not limited to, interferences, re-examinations,
reissues, oppositions relating thereto, then Array shall have the right to
prepare, file, prosecute and maintain such patent applications and patents in
such countries as it deems appropriate, and conduct such

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -17-
<PAGE>

proceedings, at its sole expense. In such case, upon Array's request, Vertex
shall immediately execute all necessary documents that may be required in order
to enable Array to file, prosecute and maintain such patent applications and to
conduct any such proceedings. Neither Party shall have an obligation to account
to the other, or obtain the consent of the other, with respect to the
exploitation (directly or through licensees of third parties) of any Joint
Technology, and each Party hereby waives any right it may have under the laws of
any jurisdiction to require such an accounting or consent.

             8.2.2 Solely-Owned Inventions. Each Party shall be responsible, at
its expense and in its sole discretion, for preparing, filing, prosecuting and
maintaining, in such countries as it deems appropriate, any and all patent
applications and patents directed to inventions solely owned by such Party
pursuant to Section 8.1 above, and conducting any interferences,
re-examinations, reissues and oppositions with respect to such patent
applications and patents.

             8.2.3 Inventions Relating to Diversity Library Compounds.
Notwithstanding any other provision of this Agreement, Vertex shall not file,
prosecute and maintain any patent applications and patents claiming a Diversity
Library Compound or pharmaceutical compositions based on such Diversity Library
Compound (including method of use or process for the synthesis thereof or
composition of matter).

         8.3 Cooperation. Each of Vertex and Array shall keep the other fully
informed as to the status of patent matters described in this Article 8 (except
Array Technology) affecting the other Party's rights under this Agreement. Array
and Vertex shall each reasonably cooperate with and assist the other at its own
expense in preparing and prosecuting patent applications that are the subject of
patent rights granted under this Article 8. Vertex shall provide, on a timely
basis, Array with copies of all patents claiming a Compound which may affect
Array's rights under this Agreement.

         8.4 Infringement Defense.

             8.4.1 If Array receives any information or a notice of alleged
infringement of a Third Party's intellectual property rights concerning the
making, having made, using, selling, leasing, offering to sell or lease,
importing, exporting or otherwise transferring physical possession of or title
in a Compound and/or Product, Array shall promptly notify Vertex and shall
provide Vertex with details concerning such information or notice.

             8.4.2 Vertex shall have the right, but not the obligation, to
defend any suit against Vertex or its Licensees alleging infringement of any
patent claim or other intellectual property right of a Third Party because of
Vertex's (or its Licensee's) practice of its licenses under this Agreement,
including the making, having made, using, selling, leasing, offering to sell or
lease, importing, exporting or otherwise transferring physical possession of or
title in a Compound or a Product by Vertex or its Licensees. If Vertex finds it
necessary or desirable, Array agrees to cooperate with Vertex (as may reasonably
be requested by Vertex) and to use its best efforts to ensure that any Array
personnel (as may reasonably be requested for assistance by Vertex) will be
available to cooperate with Vertex, at Vertex's expense, during the defense of
any such suit. If Vertex finds it necessary or

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -18-
<PAGE>

desirable for Array to join Vertex as a party, Array shall execute all papers or
perform such other acts as may reasonably be required by Vertex. The costs and
expenses of any action under this Section, including attorney fees and all
damages and settlements, including any costs incurred by Array as a result of
Vertex's requested participation and assistance of Array shall be borne by
Vertex. In any suit under this Section in which Array is joined or is named as a
party, Array shall neither admit liability or otherwise consent to an adverse
judgment, without the prior written consent of Vertex.

                                    ARTICLE 9
                           CONFIDENTIALITY AND NON-USE

         9.1 Confidential Information. Except as otherwise expressly provided
herein, the Parties agree that, for the term of this Agreement and for [***]
thereafter, the receiving Party shall not, except as expressly provided in this
Article 9, disclose to any Third Party for any purpose any Confidential
Information furnished to it by the disclosing Party hereto pursuant to this
Agreement,. Array Technology and Diversity Library Compound Information shall be
considered the Confidential Information of Array, except as otherwise provided
in this Agreement. Vertex Technology, and all other results of the Research
Collaboration that are subject to an exclusive license to Vertex shall be
considered the Confidential Information of Vertex. For purposes of this Article
9, "Confidential Information" shall also mean any information including oral or
written communications regarding Collaboration Technology and Joint Technology,
and the source data and information and/or the reports (or any data or
information contained therein), or information which if disclosed in tangible
form and is marked "confidential" or with other similar designation to indicate
its confidential or proprietary nature, or, if disclosed orally, is indicated
orally to be confidential or proprietary at the time of such disclosure and is
confirmed in writing as confidential or proprietary within forty-five (45) days
after such disclosure. Notwithstanding the foregoing, Confidential Information
shall not include any information that can be established by the receiving Party
by competent proof that such information:

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

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

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

             (d) was independently developed by the receiving Party without
access to or use of the other Party's Confidential Information, as demonstrated
by documented evidence prepared contemporaneously with such independent
development; or

                                                    [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

                                      -19-
<PAGE>

             (e) was disclosed to the receiving Party, other than under an
obligation of confidentiality, by a Third Party who had no obligation to the
disclosing Party not to disclose such information to others.

         9.2 Non-Use Obligations.

             9.2.1 Array shall not use Vertex Technology or other Vertex
Confidential Information, except for the sole purpose of conducting the Research
Collaboration at its company address listed above and not for any other use or
purpose without the prior express written consent of Vertex. Without the prior
written consent of Vertex, Array shall neither transfer nor provide access to
Vertex Technology to any Third Party, and shall maintain Vertex Technology only
at its company address set forth above. Other than for the conduct of the
Research Collaboration as expressly set forth in this Agreement, it is agreed
that the provision of Vertex Technology to Array under this Agreement shall not
constitute any grant of, option or license to Array under any Vertex
intellectual property rights or any other rights.

             9.2.2 Vertex shall not use Array Technology or other Array
Confidential Information, except for the sole purpose of exercising its rights
under this Agreement and not for any other use or purpose without the prior
written consent of Array. Without the prior written consent of Array, Vertex
shall neither transfer nor provide access to Array Technology to any Third
Party, other than as necessary to exercise its rights under this Agreement and
subject to such Third Party having agreed to be obligated to the terms of
confidentiality and non-use as set forth in this Agreement. Other than as
expressly set forth in this Agreement, it is agreed that the provision of Array
Technology to Vertex under this Agreement shall not constitute any grant of,
option or license to Vertex under any Array intellectual property rights or any
other rights.

         9.3 Permitted Use and Disclosures. Each Party hereto may use or
disclose Confidential Information disclosed to it by the other Party or Results
to the extent such use or disclosure is reasonably necessary and permitted in
the exercise of the rights granted hereunder in filing or prosecuting patent
applications, prosecuting or defending litigation, complying with applicable
governmental laws, regulations or court order or otherwise submitting
information to tax or other governmental authorities, conducting clinical
trials, or making a permitted sublicense or otherwise exercising license rights
expressly granted by the other Party to it pursuant to the terms of this
Agreement, provided that if a Party is required to make any such disclosure,
other than pursuant to a confidentiality agreement, it will give reasonable
advance notice to the other Party of such disclosure and, save to the extent
inappropriate in the case of patent applications, will use its reasonable
efforts to secure confidential treatment of such information in consultation
with the other Party prior to its disclosure (whether through protective orders
or otherwise) and disclose only the minimum necessary to comply with such
requirements.

         9.4 Termination of Prior Agreement. This Agreement supersedes the
Confidentiality Agreement between the Parties dated [***]. All information
exchanged between the Parties under that the Confidentiality Agreement shall be
deemed Confidential Information and shall be subject to the terms of this
Article 9.

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                                      -20-
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         9.5 Nondisclosure of Terms. Each of the Parties hereto agrees not to
disclose the terms of this Agreement to any Third Party without the prior
written consent of the other Party hereto, except to such Party's attorneys,
advisors, investors and others on a need to know basis under circumstances that
reasonably ensure the confidentiality thereof, or to the extent required by law.
If Array concludes that a copy of this Agreement must be filed with the U.S.
Securities and Exchange Commission, it will provide Vertex with a copy of the
Agreement to so be filed, and will provide Vertex with an opportunity to comment
on the form of the Agreement and any Sections as to which Vertex requests
confidential treatment, and will take Vertex's reasonable comments and requests
into consideration, before filing same. Notwithstanding the foregoing, the
Parties shall agree upon a joint press release, its contents and timing, and the
contents and timing of any other form of publicity or announcement relative the
execution of this Agreement. Thereafter, Array and Vertex may each disclose to
Third Parties the information contained in such press release or other public
announcement without the need for further approval by the other. In addition to
the forgoing restrictions on public disclosure, Vertex and Array may make public
statements and/or issue a press release regarding the progress of the Research
Collaboration and the achievement of milestones with respect thereto, following
consultation and mutual agreement of the Parties with respect to the consent and
timing of such public announcement and/or press release.

         9.6 Publication. Each Party may publish scientific results of its
respective work within the scope of the licenses granted under this Agreement;
provided however, that the Parties comply with the following procedure:

             (a) At least [***] days prior to submission for publication, Vertex
shall provide Array with a copy of any such planned publication by Vertex that
would disclose the Confidential Information of Array, for Array's written
consent prior to the disclosure of such Confidential Information. Array shall
notify Vertex in writing within [***] days after receipt of the planned
publication as to whether (i) Array consents to the disclosure of such
Confidential Information of Array, (ii) Array requires Vertex to remove all or
part of any Confidential Information of Array prior to publication, or (iii)
Array reasonably believes that any invention in Licensed Technology would be
disclosed by such planned publication. In the event of notice by Array under
Section 9.5(a)(ii), Vertex agrees to remove such Confidential Information of
Array requested in the notice by Array. In the event of notice by Array under
Section 9.5(a)(iii), Vertex agrees to delay publication for a reasonable time
period sufficient for a patent application thereon to be filed pursuant to
Section 8.2 (but in no event to exceed [***] days). It is understood and agreed
that failure of Vertex to receive notification from Array within [***] days of
receipt of a planned publication under this Section 9.5(a) shall be deemed
consent by Array to such publication.

             (b) At least [***] days prior to submission for publication, Array
shall provide Vertex with a copy of any such planned publication by Array that
would disclose the Confidential Information of Vertex, for Vertex's written
consent prior to the disclosure of such Confidential Information. Vertex shall
notify Array in writing within [***] days after receipt of the planned
publication as to whether (i) Vertex consents to the disclosure of such
Confidential Information of Vertex, (ii) Vertex requires Array to remove all or
part of any Confidential Information of Vertex

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                                      -21-
<PAGE>

prior to publication, or (iii) Vertex reasonably believes that any invention in
Licensed Technology would be disclosed by such planned publication. In the event
of notice by Vertex under Section 9.5(b)(ii), Array agrees to remove such
Confidential Information of Vertex requested in the notice by Vertex. In the
event of notice by Vertex under Section 9.5(b)(iii), Array agrees to delay
publication for a reasonable time period sufficient for a patent application
thereon to be filed pursuant to Section 8.2 (but in no event to exceed [***]
days). It is understood and agreed that failure of Array to receive notification
from Vertex within [***] days of receipt of a planned publication under this
Section 9.5(b) shall be deemed consent by Vertex to such publication.

             (c) Any such publication will include recognition of the Parties'
respective contributions according to standard practice for assigning scientific
credit, either through authorship or acknowledgement, as may be appropriate.

             (d) Notwithstanding the above, Array shall not publish any
scientific results that specifically relate to the Compounds.

                                   ARTICLE 10
                         REPRESENTATIONS AND WARRANTIES

         10.1 Vertex. Vertex represents and warrants on its own behalf and on
behalf of its Affiliates that: (i) it has the legal power, authority and right
to enter into this Agreement and to perform all of its obligations hereunder;
(ii) this Agreement is a legal and valid obligation binding upon it and
enforceable in accordance with its terms; (iii) it has the full right to enter
into this Agreement, and to fully perform its obligations hereunder; and (iv) it
has not previously granted, and during the term of this Agreement will not
knowingly make any commitment or grant any rights which are in conflict in any
material way with the rights and licenses granted herein.

         10.2 Array. Array represents and warrants that: (i) it has the legal
right and power to extend the rights granted in this Agreement; (ii) this
Agreement is a legal and valid obligation binding upon it and enforceable in
accordance with its terms; (iii) it has the full right to enter into this
Agreement, and to fully perform its obligations hereunder; (iv) it has not
previously granted, and during the term of this Agreement will not knowingly
make any commitment or grant any rights which are in conflict in any material
way with the rights and licenses granted herein; and (v) to the best of its
knowledge as of the Effective Date, there are no existing or threatened actions,
suits or claims pending against it with respect to the Array Technology.

         10.3 Disclaimer. Vertex and Array specifically disclaim any guarantee
that the Research Collaboration will be successful, in whole or in part. The
failure of the Parties to successfully develop Compounds and/or Products will
not constitute a breach of any representation or warranty or other obligation
under this Agreement. EXCEPT AS OTHERWISE EXPRESSLY SET FORTH IN THIS AGREEMENT,
ARRAY AND VERTEX MAKE NO REPRESENTATIONS AND EXTEND NO WARRANTIES OR CONDITIONS
OF ANY KIND, EITHER EXPRESS OR IMPLIED, WITH RESPECT TO THE VERTEX TECHNOLOGY,
ARRAY TECHNOLOGY, COMPOUNDS,

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DIVERSITY LIBRARIES, DIVERSITY LIBRARY COMPOUNDS, INFORMATION DISCLOSED
HEREUNDER OR PRODUCTS INCLUDING, BUT NOT LIMITED TO, WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, VALIDITY OF ANY COLLABORATION
TECHNOLOGY, PATENTED OR UNPATENTED, OR NONINFRINGEMENT OF THE INTELLECTUAL
PROPERTY RIGHTS OF THIRD PARTIES.

                                   ARTICLE 11
                                 INDEMNIFICATION

         11.1 Vertex. Vertex agrees to indemnify, defend and hold Array and its
Affiliates and their respective directors, officers, employees, agents and their
respective successors, heirs and assigns (the "Array Indemnitees") harmless from
and against any losses, costs, claims, damages, liabilities or expense
(including reasonable attorneys' and professional fees and other expenses of
litigation) (collectively, "Liabilities") arising, directly or indirectly out of
or in connection with Third Party claims, suits, actions, demands or judgments,
relating to (i) any Products developed, manufactured, used, sold or otherwise
distributed by or on behalf of Vertex, its Affiliates or Licensees or other
designees (including, without limitation, product liability and patent
infringement claims), (ii) Vertex's performance of the Research Collaboration,
(iii) the use of the Targets by Vertex which are involved in the conduct of the
Research Collaboration and the making or use of modulators of such Targets by
Vertex; and (iv) any breach by Vertex of the representations and warranties made
in this Agreement, except, in each case, to the extent such Array Liabilities
result from the willful negligence or willful misconduct of Array.

         11.2 Array. Array agrees to indemnify, defend and hold Vertex and its
Affiliates and their respective directors, officers, employees, agents and their
respective heirs and assigns (the "Vertex Indemnitees") harmless from and
against Liabilities arising, directly or indirectly out of or in connection with
Third Party claims, suits, actions, demands or judgments, relating to (i) the
performance of the Research Collaboration by Array, and (ii) any breach by Array
of its representations and warranties made in this Agreement, except, in each
case, to the extent such Liabilities result from the willful negligence or
willful misconduct of Vertex.

         11.3 Indemnification Procedure. A Party that intends to claim
indemnification (the "Indemnitee") under this Article 11 shall promptly notify
the other Party (the "Indemnitor") in writing of any claim, complaint, suit,
proceeding or cause of action with respect to which the Indemnitee intends to
claim such indemnification (for purposes of this Section 11.3, each a "Claim"),
and the Indemnitor shall have sole control of the defense and/or settlement
thereof; provided that the Indemnitee shall have the right to participate, at
its own expense, with counsel of its own choosing in the defense and/or
settlement of such Claim. The indemnification obligations of the Parties under
this Article 11 shall not apply to amounts paid in settlement of any Claim if
such settlement is effected without the consent of the Indemnitor, which consent
shall not be withheld or delayed unreasonably. The failure to deliver written
notice to the Indemnitor within a reasonable time after the commencement of any
such Claim, if prejudicial to its ability to defend such action, shall relieve
such Indemnitor of any liability to the Indemnitee under this Article 11, but
the

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                                      -23-
<PAGE>

omission so to deliver written notice to the Indemnitor shall not relieve the
Indemnitor of any liability to any Indemnitee otherwise than under this Article
11. The Indemnitee under this Article 11, and its employees, at the Indemnitor's
request and expense, shall provide full information and reasonable assistance to
Indemnitor and its legal representatives with respect to such Claims covered by
this indemnification. It is understood that only Vertex may claim indemnity
under this Article 11 (on its own behalf or on behalf of a Vertex Indemnitee),
and other Vertex Indemnitees may not directly claim indemnity hereunder.
Likewise, it is understood that only Array may claim indemnity under this
Article 11 (on its own behalf or on behalf of an Array Indemnitee), and other
Array Indemnitees may not directly claim indemnity hereunder.

                                   ARTICLE 12
                              TERM AND TERMINATION

         12.1 Term. The term of this Agreement shall commence on the Effective
Date, and shall continue in full force and effect, on a [***] basis, until
Vertex and its Licensees have no remaining milestone payment obligations with
respect to any Product, or unless earlier terminated as provided in Article 12.

         12.2 Termination for Breach. Either Party to this Agreement may
terminate the Research Collaboration and this Agreement in the event the other
Party hereto shall have materially breached or defaulted in the performance of
any of its material obligations hereunder, and such default shall have continued
for [***] days after written notice thereof was provided to the breaching Party
by the non-breaching Party. Any termination shall become effective at the end of
such [***] day period unless the breaching Party (or any other Party on its
behalf) has cured any such breach or default prior to the expiration of the
[***] day period; provided, however, in the case of a failure to pay any amount
due hereunder, such default may be the basis of termination [***] business days
following the date that notice of such default was provided to the breaching
Party.

         12.3 Termination for Insolvency. If voluntary or involuntary
proceedings by or against a Party are instituted in bankruptcy under any
insolvency law, or a receiver or custodian is appointed for such Party, or
proceedings are instituted by or against such Party for corporate
reorganization, dissolution, liquidation or winding-up of such Party, which
proceedings, if involuntary, shall not have been dismissed within [***] days
after the date of filing, or if such Party makes an assignment for the benefit
of creditors, or substantially all of the assets of such Party are seized or
attached and not released within [***] days thereafter, the other Party may
immediately terminate the Research Collaboration and/or this Agreement,
effective upon notice of such termination.

         12.4 Early Termination of Research Collaboration by Vertex. Vertex may,
in its absolute discretion, terminate its participation in the Research
Collaboration [***], upon [***] prior written notice to Array (the "Notice
Period"), in which event Vertex must nevertheless make all of the payments
required to be made hereunder which accrue or fall due during the Notice Period.
Array

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                                      -24-
<PAGE>

shall not change the number of Array Researchers FTEs after receipt of such
notice, unless otherwise authorized by Vertex.

         12.5 Termination [***]. In the event that during the term of the
Research Collaboration, [***] upon [***] days notice [***], and Vertex's
obligations to fund the Research Collaboration under Section 5.2 and Array's
obligation to conduct the Research Collaboration under Sections 2.3, 2.4 and 2.5
shall terminate. In addition, Article 3 (except Section 3.7.3 and Array's
obligation to submit a final report under Section 3.7.1) shall terminate.
Regardless of whether or not [***] terminates this Agreement [***], then
notwithstanding the definition of Array Improvements, Array Technology, Array
Patent Rights, Collaboration Technology, Joint Technology, Licensed Technology
and Vertex Technology (collectively the "Technologies"), Vertex shall not
acquire under this Agreement any rights to any intellectual property or subject
matter that, [***], was held or controlled by [***], except as provided in this
Section 12.5. In the event [***] terminates this Agreement under this Section
12.5, then [***] shall not acquire under this Agreement any rights to any
intellectual property or subject matter created or acquired by [***], unless
such intellectual property or subject matter (i) would otherwise be within the
Technologies (i.e., if created by Array prior [***]), (ii) was created by an
individual who was an employee of [***], and (iii) was so created [***] in the
course of activities directed to the Field. Except for those activities
described in clause (iii) above which were conducted by an individual described
in clause (ii) above, no activities of [***] shall be deemed within the
Technologies.

         12.6 Effect of Breach or Termination.

              12.6.1 Accrued Rights and Obligations. Termination of this
Agreement for any reason shall not release either Party hereto from any
liability which, at the time of such termination, has already accrued to the
other Party or which is attributable to a period prior to such termination nor
preclude either Party from pursuing any rights and remedies it may have
hereunder or at law or in equity with respect to any breach of this Agreement.

              12.6.2 Return of Materials. Upon any termination of this
Agreement, Vertex and Array shall promptly return to the other all Confidential
Information received from the other Party, except one copy of which may be
retained for archival purposes.

              12.6.3 Material Breach for Non-Payment. In the event (i) Vertex
fails to make any payment due Array under Section 5.3.1 or 5.3.2, (ii) this
payment dispute is not resolved through the provisions set forth in Section
13.12, (iii) Array thereafter institutes proceedings to obtain such payment, and
(iv) as a result of such proceedings, whether by judgement or settlement
thereof, Vertex is required to make all or part of such payment, [***].

         12.7 Survival. Any rights or obligations set forth under this Agreement
which of their nature are intended to extend beyond the term of the Agreement
shall survive, including, but not

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limited to, 5.3.1, 5.3.2, 6.2, and 12.7 of this Agreement, and Articles 1, 9,
11, 12 and 13 shall survive the expiration or termination of this Agreement for
any reason.

                                   ARTICLE 13
                                  MISCELLANEOUS

         13.1 Governing Laws. This Agreement shall be governed by and
interpreted in accordance with the substantive laws of the Commonwealth of
Massachusetts, without reference to the conflicts of law principles thereof. The
parties hereby acknowledge their diversity (Array having its principal place of
business in Colorado and Vertex having its principal place of business in
Massachusetts) and, if Array brings suit under this Agreement such suit shall be
brought in Federal District Court in Boston, Massachusetts or the Massachusetts
state courts of general jurisdiction in Boston, Massachusetts (and the parties
will submit to the jurisdiction thereof); and, if Vertex brings suit under this
Agreement, such suit shall be brought in the Federal District Court in Denver,
Colorado or the Colorado state courts of general jurisdiction in Denver,
Colorado (and the parties will submit to the jurisdiction thereof).

         13.2 Waiver. It is agreed that no waiver by either Party hereto of any
breach or default of any of the covenants or agreements herein set forth shall
be deemed a waiver as to any subsequent and/or similar breach or default.

         13.3 Assignment. This Agreement shall not be assignable by either Party
to any Third Party hereto without the written consent of the other Party hereto.
Notwithstanding the foregoing, either party may assign this Agreement, without
such consent, to an entity that acquires all or substantially all of the
business or assets of such Party to which this Agreement pertains, whether by
merger, reorganization, acquisition, sale, or otherwise; provided, however, that
within thirty (30) days of such an assignment, the assignee shall agree in
writing to be bound by the terms and conditions of this Agreement, provided
further, however, that either Party may still exercise its rights under Section
12.5. This Agreement shall be binding upon and accrue to the benefit any
permitted assignee, and any such assignee shall agree to perform the obligations
of the assignor.

         13.4 Independent Contractors. The relationship of the Parties hereto is
that of independent contractors. The Parties hereto are not deemed to be agents,
employer-employee, partners or joint venturers of the others for any purpose as
a result of this Agreement or the transactions contemplated thereby. Array shall
use its own discretion and shall have complete and authoritative control over
its employees and Array Researchers, and the details of performing its
obligations under this Agreement.

         13.5 Compliance with Laws. In exercising their rights under this
license, the Parties shall fully comply in all material respects with the
requirements of any and all applicable laws, regulations, rules and orders of
any governmental body having jurisdiction over the exercise of rights under this
license including, without limitation, those applicable to the discovery,
development, manufacture, distribution, import and export and sale of Products
pursuant to this Agreement.

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         13.6 Notices. All notices, requests and other communications hereunder
shall be in writing and shall be deemed to be sufficient if personally delivered
or by registered or certified mail, return receipt requested, postage prepaid,
transmitted by commercial overnight courier, or transmitted by telex, telegram
or telecopy (receipt verified) in each case to the respective address specified
below, or such other address as may be specified in writing to the other Parties
hereto and shall be deemed to have been given upon receipt:

              If to Vertex:
              Vertex Pharmaceuticals, Inc.
              130 Waverly Street
              Cambridge, Massachusetts 02139-4242
              Attention:  Leland C. Webster, Ph.D.
              Facsimile:   (617) 444-6680

              with a copy to:
              Attn.: Legal Department
              130 Waverly Street
              Cambridge, Massachusetts 02139-4242
              Facsimile:  (617) 444-6483

              If to Array:
              Array BioPharma Corporation
              1885 33rd Street
              Boulder, CO  80301
              Attention:  David L. Snitman, Ph.D.
              Facsimile:  (303) 449-5376

              with a copy to:
              Wilson Sonsini Goodrich & Rosati
              650 Page Mill Road
              Palo Alto, CA  94304-1050
              Attention:  Kenneth A. Clark, Esq.
              Facsimile:  (650) 493-6811

         13.7 Severability. Each Party hereby agrees that it does not intend to
violate any public policy, statutory or common laws, rules, regulations, treaty
or decision of any government agency or executive body thereof of any country or
community or association of countries. Should one or more provisions of this
Agreement be or become invalid, the Parties hereto shall substitute, by mutual
consent, valid provisions for such invalid provisions which valid provisions in
their economic effect are sufficiently similar to the invalid provisions that it
can be reasonably assumed that the Parties

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would have entered into this Agreement with such valid provisions. In case such
valid provisions cannot be agreed upon, the invalidity of one or several
provisions of its Agreement shall not affect the validity of this Agreement as a
whole, unless the invalid provisions are of such essential importance to this
Agreement that it is to be reasonably assumed that the Parties would not have
entered into this Agreement without the invalid provisions.

         13.8 Advice of Counsel. Array and Vertex have each consulted counsel of
their choice regarding this Agreement, and each acknowledges and agrees that
this Agreement shall not be deemed to have been drafted by one Party or another
and will be construed accordingly.

         13.9 Performance Warranty. Each Party hereby warrants and guarantees
the performance of any and all rights and obligations of this Agreement by its
Affiliates and Licensees.

         13.10 Force Majeure. Neither Party shall lose any rights hereunder or
be liable to the other Party for damages or losses (except for payment
obligations) on account of failure of performance by the defaulting Party if the
failure is occasioned by war, strike, fire, Act of God, earthquake, flood,
lockout, embargo, governmental acts or orders or restrictions, failure of
suppliers, or any other reason where failure to perform is beyond the reasonable
control and not caused by the negligence, intentional conduct or misconduct of
the non-performing Party and such Party has exerted all reasonable efforts to
avoid or remedy such force majeure; provided, however, that in no event shall a
Party be required to settle any labor dispute or disturbance.

         13.11 Complete Agreement. This Agreement with its Exhibits, constitutes
the entire agreement, both written and oral, between the Parties with respect to
the subject matter hereof, and all prior agreements respecting the subject
matter hereof, either written or oral, express or implied, shall be abrogated,
canceled, and are null and void and of no effect. No amendment or change hereof
or addition hereto shall be effective or binding on either of the Parties hereto
unless reduced to writing and executed by the respective duly authorized
representatives of Array and Vertex. Any inconsistencies between this Agreement
and the Research Plan shall be resolved in favor of the Agreement.

         13.12 Consultation. If an unresolved dispute arises out of or relates
to this Agreement, or the breach thereof, either Party may refer such dispute to
the Chief Executive Officer of Vertex and the Chief Executive Officer of Array,
or such Parties' designated representative (provided such representative is at
least a Vice President or above), who shall meet in person or by telephone
within forty-five (45) days after such referral to attempt in good faith to
resolve such dispute.

         13.13 Headings. The captions to the several Sections hereof are not a
part of this Agreement, but are included merely for convenience of reference and
shall not affect its meaning or interpretation.

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

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                           [SIGNATURE PAGE TO FOLLOW]

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                                [SIGNATURE PAGE]

                             COLLABORATION AGREEMENT

         IN WITNESS WHEREOF, the Parties hereto have caused this Agreement to be
duly executed by their authorized representatives and delivered in duplicate
originals as of the Effective Date.

VERTEX PHARMACEUTICALS                     ARRAY BIOPHARMA INC.
INCORPORATED

By: /s/                                    By: /s/
   ------------------------------             ----------------------------------

Name:                                      Name:
     ----------------------------               --------------------------------

Title:                                     Title:
      ---------------------------                -------------------------------

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                             COLLABORATION AGREEMENT
                                    EXHIBIT A
                                  RESEARCH PLAN

[***].

[***]:

         [***]

[***]:

         [***]

[***]:

         [***]

[***]:

                  [***]

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                             COLLABORATION AGREEMENT

                                    EXHIBIT B
                    DIVERSITY LIBRARY COMPOUND SPECIFICATIONS

The Diversity Library Compounds shall conform to the following specifications:

[***]

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                                                                    EXHIBIT 10.3
                     DRUG DISCOVERY COLLABORATION AGREEMENT

         THIS DRUG DISCOVERY COLLABORATION AGREEMENT ("Agreement"), effective as
of August 7, 2001 ("Effective Date"), is made by and between ICOS Corporation, a
Delaware corporation having its principle offices located at 22021 20th Avenue
S.E., Bothell, WA 98021, (hereinafter "ICOS"), and ARRAY BIOPHARMA CORPORATION,
a Delaware corporation having its principle offices located at 1885 33rd Street,
Boulder, CO 80301, (hereinafter "Array").

                                   BACKGROUND

     A. Array has skills, expertise and experience in developing and generating
focus libraries, and in lead optimization, computational chemistry and medicinal
chemistry;

     B. As of the Effective Date, ICOS has developed and owns certain know-how,
intellectual property rights, assays, methods, and hit compounds that may be
potential drug candidates directed to certain [***] targets;

     C. ICOS and Array desire to collaborate to identify orally active small
molecules for the therapeutic or prophylactic treatment of diseases and
conditions in humans, the mechanism of action of which is to modulate the
activity of specific Active Targets (as defined below), with the goal of
delivering compounds with desired activity and selectivity, all on the terms and
conditions herein.

     NOW, THEREFORE, in consideration of the mutual promises herein, the parties
agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

     1.1 "Active Target" shall have the meaning set forth in Section 2.2 below.

     1.2 "Affiliate" shall mean any corporation or other entity which is
directly or indirectly controlling, controlled by or under common control of a
Party hereto for so long as such control exists. For the purposes of this
Section 1.2, "control" shall mean the direct or indirect ownership of at least
fifty percent (50%) of the outstanding shares or other voting rights of the
subject entity having the power to vote on or direct the affairs of the entity,
or if not meeting such preceding condition, the maximum voting right that may be
held by the particular Party under the laws of the country where such entity
exists.
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<PAGE>

     1.3 "Array Technology" shall mean patents or other rights to compositions,
methodologies, and processes for the high speed synthesis of chemical entities
owned by Array. Array Technology shall not include Compounds, IDAS Focus
Libraries or Drug Development Candidates.

     1.4 "Collaboration Technology" shall mean all inventions and other
intellectual property, including without limitation any Patent Rights and
Know-How relating thereto, made by Array and/or ICOS in the course of performing
or in connection with the Research Program. It is understood that the
Collaboration Technology shall not include any Array Technology.

          (a) "Patent Rights" shall mean (i) all patents and patent applications
     the subject of which is an invention conceived and reduced to practice
     solely or jointly by Array and/or ICOS in the course of performing the
     Research Collaboration, that claim a Compound, including without limitation
     a Drug Development Candidate, or method of use or process for the synthesis
     thereof or composition-of-matter containing such Compound, and (ii) any
     divisions, continuations, continuations-in-part, reissues, reexaminations,
     extensions or other governmental actions which extend any of the subject
     matter of the patent applications or patents in (i) above, and any
     substitutions, confirmations, registrations or revalidations of any of the
     foregoing, to the extent Array or ICOS has the right to license the same;
     provided, however, that Patent Rights shall not include any Array
     Technology.

          (b) "Know-How" shall mean all ideas, inventions, data, instructions,
     processes, formulas, expert opinions and information, including, without
     limitation, biological, chemical, pharmacological, toxicological,
     pharmaceutical, physical and analytical, clinical, safety, manufacturing
     and quality control data and information developed solely or jointly by
     Array and ICOS during and in connection with the Research Collaboration, in
     each case, which is necessary for the development, manufacture, use or sale
     or commercialization of Compounds or Products, to the extent Array or ICOS
     has the right to license or sublicense the same; provided, however, that
     Know-How does not include any Array Technology or any inventions otherwise
     included in the Patent Rights.

     1.5 "Compound" shall mean a chemical entity synthesized by or on behalf of
Array and delivered to ICOS in the course of the Research Program. As used
herein, Compound shall include IDAS Focus Library Compounds and Drug Development
Candidates.

     1.6 "Confidential Information" shall mean any information disclosed by a
Party (the "Disclosing Party") to the other Party (the "Receiving Party") which
if disclosed in tangible form is marked "confidential" or with other similar
designation to indicate its confidential or proprietary nature or if disclosed
orally is indicated orally to be confidential or proprietary by the Disclosing
Party at the time of such disclosure and is confirmed in writing as confidential
or proprietary by the Disclosing Party within forty-five (45) days after such
disclosure. Notwithstanding the foregoing,

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Confidential Information shall not include any information that, in each case as
demonstrated by written documentation:

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

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

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

          (d) was subsequently lawfully disclosed to the Receiving Party by a
     third party who did not acquire it directly or indirectly from the
     Disclosing Party;

          (e) was developed by the Receiving Party without use of or reference
     to any Confidential Information of the Disclosing Party.

     1.7 "Consumer Price Index" or "CPI" means the Consumer Price Index, All
Urban Consumers, as published by the U.S. Bureau of Labor Statistics.

     1.8 "Derivative" shall mean a compound (or compounds) which (i) has
resulted from a chemical synthesis program by ICOS based on one or more
Compounds or (ii) is based on structure-activity data relating to a Compound
which is active or inactive in the Field. "Derivative" shall also include any
compound made based on, derived from, or related to another Derivative in any
way set forth in subsections (i) or (ii) above.

     1.9 "Drug Development Candidate" shall mean any Compound designated as a
Drug Development Candidate as set forth in Section 2.6.

     1.10 "Drug Development Targets" shall mean those IDAS targets listed in
Exhibit A, or as otherwise agreed in writing by the Parties.

     1.11 "Europe" shall mean those countries listed in Exhibit B.

     1.12 "Extension Period" shall have the meaning set forth in Section 2.7(b)
below.

     1.13 "Field" shall mean the discovery, development and commercialization of
active small molecules for the therapeutic or prophylactic treatment of diseases
and conditions in humans, the mechanism of action of which is to modulate the
activity of an Active Target.

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     1.14 "FTE" shall mean a full-time person dedicated to the Research Program,
or in the case of less than a full-time, dedicated person, a full-time,
equivalent person year, based upon a total of one thousand eight hundred eighty
(1,880) hours per year of work in connection with the Research Program.

     1.15 "IDAS Focus Library" shall mean a combinatorial compound library that
is based on a Compound or other chemical entity identified by ICOS as having
activity against a Drug Development Target.

     1.16 "IDAS Focus Library Compound" shall mean any chemical entity that is
contained in an IDAS Focus Library.

     1.17 "NDA" shall mean a New Drug Application, as defined in the U.S. Food,
Drug and Cosmetic Act and the regulations promulgated thereunder, or any
corresponding foreign application, registration or certification.

     1.18 "Net Sales" shall mean the gross invoice price by ICOS or its
Affiliates or Sublicensees, as the case may be, for all Products sold by ICOS,
its Affiliates or Sublicensees ("Selling Party"), under this Agreement in arm's
length sales to Third Parties, less deductions allowed to the Third Party
customer by the Selling Party on such sales for: (a) trade, quantity, and cash
discounts; (b) credits, rebates (including those to managed-care entities and
government agencies), and allowances or credits to customers on account of
rejection or returns (including, but not limited to, wholesaler and retailer
returns) or on account of retroactive price reductions affecting such Product;
(c) freight, postage and duties; and (d) sales and excise taxes, other
consumption taxes, customs duties and compulsory payments to governmental
authorities and any other governmental charges imposed upon the sale of such
Product to Third Parties. In addition, the Selling Party may exclude from Net
Sales a reasonable provision for uncollectible accounts, to the extent such
reserve is determined in accordance with generally accepted accounting
standards, consistently applied across all product lines of the particular
Party, until such amounts are actually collected. Notwithstanding the foregoing,
Net Sales shall not include sales among ICOS, its Affiliates and Sublicensees
for resale, provided that such resale shall be included within Net Sales.

     1.19 "Party" or "Parties" shall mean, respectively, Array or ICOS
individually, or Array and ICOS collectively.

     1.20 "Patent" shall mean (a) an issued, granted, valid and enforceable U.S.
or non U.S. Patent, and any non-U.S. equivalent, including any extension
(including Supplemental Protection Certificates), registration, confirmation,
reissue, continuation, divisionals, continuation-in-part, reexamination or
renewal thereof, or (b) pending applications for any of the foregoing.

     1.21 "Phase III" shall mean human clinical trials, the principal purpose of
which is to establish safety and efficacy of one or more particular doses in
patients being studied, and which will

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<PAGE>
(or are intended to) satisfy the requirements of a pivotal trial for purposes of
obtaining approval of a Product in a country by the health regulatory authority
in such country to market such Product.

     1.22 "Product" shall mean any product incorporating as an active ingredient
a Compound, a Drug Development Candidate or a Derivative.

     1.23 "Research Management Committee" shall have the meaning set forth in
Section 3.1 below.

     1.24 "Research Plan" shall have the meaning set forth in Section 2.3 below.

     1.25 "Research Program" shall mean the research activities undertaken by
the Parties pursuant to Article 2 below.

     1.26 "Research Term" shall have the meaning set forth in Section 2.7(a)
below.

     1.27 "SAR Information" shall mean information relating to the relationship
between the biological activity of a chemical entity and its molecular
structure.

     1.28 "Sublicensee" shall mean, with respect to a particular Product, a
Third Party to whom ICOS has granted a sublicense to make and sell such Product.
As used in this Agreement, "Sublicensee" shall also include a Third Party to
whom ICOS has granted the right to distribute such Product, provided that such
Third Party has responsibility for marketing and promotion of such Product
within the field or territory for which such distribution rights are granted.

     1.29 "Third Party" shall mean any person or entity other than Array and
ICOS, and their respective Affiliates.

     1.30 "Valid Claim" shall mean (i) an issued, granted and enforceable claim
in a Patent, or (ii) a claim of a patent application within the Patent Rights,
which claim has been pending less than two (2) years from the filing date of
such claim.

                                    ARTICLE 2
                                RESEARCH PROGRAM

     2.1 Objectives. The goal of the Research Program is the generation of
Compounds and the identification of Drug Development Candidates within the
Field.

     2.2 Targets.

          (a) General. Except as otherwise provided in this Section 2.2, the
     Research Collaboration shall be focused on identifying chemical entities
     that have activity against [***]

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     specific Drug Development Targets (each an "Active Target"). The Parties
     have agreed that the [***] protein target shall be an Active Target as of
     the Effective Date.

               (i) Within [***] after the Effective Date, ICOS shall select a
          [***] from the remaining Drug Development Targets, and upon notice to
          Array of such selection, the selected Drug Development Target shall be
          deemed an Active Target for purposes of this Agreement.

               (ii) During the Research Term, the Research Plan may provide for
          the conduct of screening activities directed toward each of the Drug
          Development Targets, regardless of whether such Target has been
          designated as an Active Target hereunder.

          (b) Abandonment and Substitution of Targets. The Research Management
     Committee may decide to discontinue research activities with respect to one
     or more Active Targets, in which event (i) such Active Target shall not
     after the effective date of such decision be, or be deemed to be, an Active
     Target for purposes of this Agreement. In the event that research
     activities are discontinued with respect to any Active Target pursuant to
     this Section 2.2(b), then ICOS may substitute, after discussion with the
     Research Management Committee and mutual agreement of the Parties, another
     Drug Development Target in its place as an Active Target for purposes of
     this Agreement.

          (c) Additional Drug Development Targets. Upon request of ICOS and
     subject to the consent of Array, the Research Collaboration may be expanded
     to include additional Drug Development Targets in excess of the number set
     forth in Section 2.2(a), but under no circumstances shall there be more
     than [***] Drug Development Targets at any one time which may be considered
     for research activities under this Agreement.

          (d) Screening. ICOS may use any Compounds supplied by Array for
     screening on other targets outside the Field at any time.

         2.3 Research Plan. The Research Program shall be carried out in
accordance with a mutually agreed upon written "Research Plan", which shall
establish specific research objectives and the research tasks to be performed
and resources to be provided by each Party. The Research Plan shall, among other
things, establish: (i) the scope of the research activities which will be
performed; (ii) the research objectives and work plan activities; (iii) the
respective obligations of the Parties with respect to the Research Program; and
(iv) specific screening assays for identifying and testing the activity of
compounds against an Active Target. The proposed research plan, with such
changes as are mutually agreed shall become the initial "Research Plan".

          (a) Periodic Review. The Research Plan shall be reviewed on an ongoing
     basis and may be amended by the Research Management Committee.

         2.4 Research Program Activities. Subject to the terms and conditions
set forth herein, the parties agree to conduct research under the Research Plan.
During the Research Term, Array and

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ICOS shall each use their commercially diligent efforts to identify Compounds
having activity against an Active Target and Drug Development Candidates in
accordance with the Research Plan.

          (a) Array Responsibilities. During the Research Term, Array shall make
     the following resources available in connection with the obligations as
     specified in the Research Plan:

               (i) Review data and information, including SAR Information,
          regarding the Active Targets, screening hits and lead compounds
          provided by ICOS;

               (ii) Based on data and information, including SAR Information,
          regarding the Active Targets, screening hits and lead compounds
          provided by ICOS, use computational and structural biology to
          construct IDAS Focus Libraries and optimize the screening hits and
          lead compounds supplied or identified by ICOS;

               (iii) Validate and optimize such Compounds having activity
          against each Active Target;

               (iv) Perform such computational and medicinal chemistry as
          necessary for the construction of Drug Development Candidates; and

               (v) Evaluate most potent antagonists via pharmacokinetic analysis
          and metabolite profiling.

In performing its obligations under (ii) above, [***].

          (b) ICOS Responsibilities. During the Research Term, ICOS shall be
     primarily responsible for the following obligations, as specified in the
     Research Plan, among others:

               (i) Primary and secondary screening for activity and selectivity;

               (ii) In vitro and in vivo assays and animal models;

               (iii) Establishing mechanism of action;

               (iv) Pre-clinical and clinical development; and

               (v) Provide Array with such necessary support and assistance as
          Array may reasonably require, including without limitation, providing
          Array with screening hits, lead compounds, SAR Information and other
          data and information regarding the Active Targets.

          (c) Reporting. During the Research Term, the parties shall provide the
     Research Management Committee with regular reports on the results of the
     Research Program. Such reports shall be in a form to be mutually agreed by
     the parties.

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     2.5 Research Program Staffing. In consideration of the services provided by
Array in performance of the Research Program, ICOS shall fund Array FTEs
performing research under the Research Plan in accordance with Section 5.1 below
and this Section 2.5; further, applicable milestones and royalties shall be paid
when due and owing. Unless the Parties otherwise agree in writing, the Research
Plan shall provide for [***] Array FTEs per year.

     2.6 Drug Development Candidates. The parties have established that a
chemical entity which meets the reasonable internal guidelines established by
ICOS for advancing a Compound into pre-clinical studies shall be a Drug
Development Candidate. Any Compound which has been selected by ICOS to undergo
GLP toxicology studies to support a regulatory filing, shall be deemed a Drug
Development Candidate upon such selection. ICOS shall promptly notify Array of
the identification of any Drug Development Candidate.

     2.7 Term and Termination of Research Program. The Research Program shall
commence on the Effective Date and continue for the Research Term (as defined
below).

          (a) Research Term. The "Research Term" shall mean the period
     commencing on the Effective Date and ending on the first to occur of (i)
     termination of this Agreement; or (ii) the later of [***] after the
     Effective Date, or the end of the Extension Period if the Research Term is
     extended under Section 2.7(b) below.

          (b) Extension Period. The parties may extend the Research Term for
     additional [***] periods upon mutual agreement of the parties (the
     "Extension Period").

     2.8 Records; Inspection and Retention.

          (a) Research Program. Array shall maintain records of the Research
     Program (or cause such records to be maintained) in sufficient detail and
     in good scientific manner as will properly reflect all work done and
     results achieved in the performance of the Research Program. During the
     Research Term and for a period of [***] thereafter, Array shall allow ICOS
     to have reasonable access to all pertinent materials and data generated by
     Array with respect to synthesis of each Compound in connection with the
     Research Program. Array shall retain such records for a period of [***], or
     such other period agreed by the parties. After this time and on request by
     ICOS, Array shall provide to ICOS copies of all such records associated
     with any Drug Development Candidate and patents or patent applications
     claiming such Drug Development Candidate for retention in ICOS's archives.

          (b) Research Program Expenditures. Array shall keep complete, true and
     accurate books of account and records of the amounts it expends in
     connection with the performance of the Research Program.

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     2.9 Post Research Collaboration Activities. For each Drug Development
Candidate and Product to which ICOS retains rights under this Agreement, Array
shall have no responsibility or expense, for conducting any clinical development
and/or commercialization of such Products.

     2.10 Exclusivity. Except as set forth herein, during the period commencing
on the Effective Date and ending [***] after the end of the Research Term, Array
shall not knowingly conduct, participate in, or fund, directly or indirectly,
alone or with a Third Party, discovery research specifically directed to the
Field, except pursuant to this Agreement. In addition, during the Research Term,
Array shall not knowingly conduct, participate in, or fund, directly or
indirectly, alone or with a Third Party, discovery research specifically
directed to the discovery, development and commercialization of active small
molecules for the therapeutic or prophylactic treatment of diseases and
conditions in humans, the mechanism of action of which is to modulate the
activity of a Drug Development Target that is not an Active Target, except
pursuant to this Agreement. Further, during the Research Term and for a period
of [***] thereafter, Array shall not knowingly conduct, participate in, or fund,
directly or indirectly, alone or with other Third Parties, discovery research
specifically directed to the discovery, development and commercialization of
active small molecules for the therapeutic or prophylactic treatment of diseases
and conditions in humans, the mechanism of action of which is [***].
Notwithstanding the foregoing, in the event of a Change of Control of Array, the
provisions of this Section 2.10 shall not apply to the surviving entity. For
purposes of this Section 2.10, a "Change of Control" shall mean the merger,
consolidation, sale of substantially all of its assets or similar transaction or
series of transactions, as a result of which Array's shareholders before such
transaction or series of transactions own less than fifty percent (50%) of the
total number of voting securities of the surviving entity immediately after such
transaction or series of transactions. Notwithstanding the foregoing, if as a
result of any such Change of Control, Array exists as a wholly owned subsidiary
of a parent, then the provisions of this Section 2.10 shall continue to apply to
Array, but not to such parent.

                                    ARTICLE 3
                                   MANAGEMENT

         3.1 Research Management Committee. As soon as practicable after the
Effective Date and in any event not later than fifteen (15) days, ICOS and Array
will convene the first meeting of a committee to oversee, review, co-ordinate
and recommend direction of the Research Program (the "Research Management
Committee"). The responsibilities of the Research Management Committee shall
include, among other things: (i) monitoring and reporting research progress and
ensuring open and frequent exchange between the Parties regarding Research
Program activities; (ii) coordination of a collaborative discovery and
optimization program to identify Drug Development Candidates for each Target;
and (iii) amending as necessary the criteria for the selection of Drug
Development Candidates for each Target.

         3.2 Membership. The Research Management Committee shall include two (2)
representatives of each of ICOS and Array, each Party's members selected by that
Party and the

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Parties hereto shall nominate and name their representations not
later than the Effective Date. Array and ICOS may each replace its Research
Management Committee representatives at any time, upon written notice to the
other Party. From time to time, the Research Management Committee may establish
subcommittees, to oversee particular projects or activities, and such
subcommittees will be constituted organised and structured as the Research
Management Committee agrees but shall not hold any greater powers than the
Research Management Committee itself.

     3.3 Meetings. During the Research Term, the Research Management Committee
shall meet at least quarterly, or as agreed by the Parties, at such locations as
the Parties agree, and will otherwise communicate regularly by telephone,
electronic mail, facsimile and/or video conference. Other representatives of
Array or ICOS may attend Research Management Committee meetings as observers.
Each Party shall be responsible for all of its own expenses associated with
attendance of such meetings.

     3.4 Minutes. The Research Management Committee shall keep accurate minutes
of its meetings which shall record all proposed decisions and all actions
recommended or taken. The Secretary of the Research Management Committee (as
appointed by the members of the Research Management Committee) shall be
responsible for the preparation of draft minutes. Draft minutes shall be sent to
all members of the Research Management Committee after each meeting and shall be
approved, if appropriate, at the next meeting. All records of the Research
Management Committee shall at all times be available to both Array and ICOS.

     3.5 Decision Making. Decisions of the Research Management Committee shall
be made by majority agreement. [***].

                                    ARTICLE 4
                                    LICENSES

     4.1 Research Use Licenses.

          (a) Grant from ICOS. ICOS hereby grants Array a worldwide,
     non-exclusive, non-transferable, non-sublicensable, royalty-free, right and
     license under any/all applicable ICOS Technology and ICOS's interest in the
     Collaboration Technology solely to conduct activities designated to Array
     under the Research Plan during the Research Term.

          (b) Grant from Array. Array hereby grants ICOS a worldwide,
     non-exclusive, non-transferable, non-sublicensable, royalty-free, right and
     license under Array's interest in the Collaboration Technology solely to
     conduct activities designated to ICOS under the Research Plan, during the
     Research Term.

          (c) Limitations on Licenses under this Section. The licenses granted
     under this Section 4.1 shall not include the right to grant or authorize
     sublicenses; provided, however, that the

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     use by ICOS or Array of subcontractors approved by the Research Management
     Committee shall not be construed as a sublicense. Neither Array nor ICOS
     shall have any right to sell or otherwise distribute any products by virtue
     of the licenses set forth in this Section 4.1 and no such sale or
     distribution right shall be implied.

     4.2 Exclusive License. Array hereby grants to ICOS a worldwide exclusive
license, with the right to grant and authorize sublicenses, under Array's
interest in the Collaboration Technology, to make, have made, use, sell, lease,
offer to sell or lease, import, export or otherwise transfer physical possession
of or title in Compounds, Drug Development Candidates and Products.

     4.3 Marketing Rights. ICOS shall have the exclusive right to market, sell
and distribute Products in the Field and outside the Field. In exercising such
rights, ICOS may select trademarks for such Products, and ICOS shall own all
right, title or interest in such trademarks (subject to any pre-existing rights
of Array or Third Parties).

     4.4 No Implied Licenses. Only the licenses granted pursuant to the express
terms of this Agreement shall be of any legal force or effect. No other license
or rights, including without limitation any license or right to Array Technology
shall be created by implication, estoppel or otherwise.

     4.5 No Commercialization Other than Products. Except as otherwise agreed in
writing or specifically provided in the terms of this Agreement, neither ICOS
nor its Affiliates nor Licensees shall, directly or indirectly commercialize any
Compound, Drug Development Candidate or Derivative in the Field or outside the
Field, other than as a Product in accordance with this Agreement.

                                    ARTICLE 5
                                    PAYMENTS

     5.1 Research Program Funding. In consideration of the services to be
performed by Array under this Agreement, ICOS shall pay Array for the FTE costs
and Development Costs incurred by Array in accordance with performance of the
Research Plan, as described more fully below.

          (a) FTEs. During the Research Term, ICOS agrees to pay Array research
     funding for the conduct of the Research Program quarterly, in advance, in
     an amount equal to the number of Array FTEs called for in the Research Plan
     for the applicable quarter multiplied by the Array FTE Rate (as defined
     below). The range of FTEs for particular periods within the Research Term
     is set forth in Section 2.5, as may be modified by the Research Plan. The
     "Array FTE Rate" shall be equal to [***] U.S. dollars [***] per FTE per
     year. Effective after the [***] of the Effective Date, the FTE Rate shall
     increase [***] by the percentage increase, if any, in the Consumer Price
     Index for all Urban Consumers, as published by the U.S. Department of
     Labor, Bureau of Statistics, since the Effective Date or the last
     adjustment hereunder, whichever is later. The payments subject to this

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     Section 5.1(a) shall be paid in quarterly installments, in advance. The
     initial payment shall be made on or before the date Array FTEs are first
     deployed in accordance with the Research Plan, and subsequent payments
     shall be made on or before the first day of each calendar quarter
     thereafter. Such payments are non-refundable.

          (b) Non-FTE Costs. ICOS also agrees to reimburse Array for any
     extraordinary chemical costs incurred by Array which are approved in
     writing by ICOS.

          (c) No Withholding. All amounts paid by ICOS to Array pursuant to this
     Section 5.1 shall be made without withholding for taxes or any other
     charge.

     5.2 Milestones. ICOS shall pay to Array the following amounts within [***]
days (or as otherwise specified below) following the first achievement by ICOS,
its Affiliates, Sublicensees or other designees, as the case may be, of each of
the following milestones with respect to each Active Target:

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<TABLE>
<CAPTION>
         MILESTONES                             PAYMENT AMOUNT
         ----------                             --------------
        <S>                                    <C>

         1. [***]                               [***]

         2. [***]                               [***]

         3. [***]                               [***]

         4. [***]                               [***]

</TABLE>

          (a) Certain Terms.

               (i) The milestone payments set forth above shall be payable [***]
          for each Active Target.

               (ii) In the event that one or more milestone payments described
          above becomes due and one or more of the earlier-stage milestone
          payments has not been paid to Array for the same Active Target, then
          all earlier-stage milestone payments that have not been paid shall be
          paid together with such due milestone payment.

               (iii) For purposes of this Section 5.2, a clinical trial shall be
          deemed initiated upon the first dosing of the first patient in such
          trial. Compassionate or emergency use, as defined in 21 CFR ss.ss.
          312.34 - 312.36 or the substantial equivalent in any country, of any
          Active Target shall not constitute a clinical trial.

     5.3 One time per Active Target Success Bonus. ICOS will pay Array a success
bonus of [***] for each Active Target in the event that the following criteria
are met for any Active Target.

          (a) within [***] from the Effective Date, Array delivers the Active
     Compound which will become a Drug Development Candidate for a particular
     Active Target, for which Active Compound ICOS completes the "in life" phase
     of at least [***] duration, of GLP-toxicology studies sufficient to produce
     a quality assured draft and final reports to enable Phase I FDA (or
     equivalent) clinical trials; and

          (b) Array delivered the Active Compound that became such Drug
     Development Candidate in sufficient quantity to enable ICOS to:

               (i) qualify such Active Compound as a Drug Development Candidate;
          and

               (ii) perform a minimum of [***] non-GLP exploratory toxicology
          studies.

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     Such success bonus payment shall be made [***] following the completion of
all the above criteria.

     5.4 Royalties.

          (a) Products in the Field. ICOS shall pay Array an annual royalty on
     Net Sales of Products sold by or under authority of ICOS, its Affiliates or
     Sublicensees for uses in the Field and which but for the Licenses granted
     herein by Array to ICOS would infringe a Valid Claim within Patents within
     the Collaboration Technology. The annual royalty rate for such Products in
     a given year shall be determined by the total annual Net Sales of all such
     Products for the particular calendar year in the particular territory
     listed below, on a calendar year basis, according to the following
     schedule:

<TABLE>
<CAPTION>
                                                           ROYALTY ON NET SALES            ROYALTY ON NET SALES IN ALL
                                  ROYALTY ON NET               ON A COUNTRY BY                 COUNTRIES OUTSIDE
ANNUAL NET SALES                  SALES IN U.S.           COUNTRY BASIS IN EUROPE              U.S. AND EUROPE
----------------              ------------------------    ----------------------------    --------------------------
<S>                               <C>                         <C>                          <C>

           [***]                        [***]                        [***]                           [***]

           [***]                        [***]                        [***]                           [***]

           [***]                        [***]                        [***]                           [***]
</TABLE>

          (b) Products outside the Field. ICOS shall pay Array an annual royalty
     on Net Sales of Products sold by or under authority of ICOS, its Affiliates
     or Sublicensees for uses outside the Field. The annual royalty rate for
     such Products shall be [***] of the total annual Net Sales of all such
     Products for each calendar year and which but for the Licenses granted
     herein by Array to ICOS would infringe a a Valid Claim within Patents
     within the Collaboration Technology.

          (c) Royalty Term. ICOS's obligation to pay annual royalties to Array
     under this Section 5.4 shall continue for each Product, on a
     country-by-country basis, until the expiration of the last to expire issued
     Patent (i.e., as defined in Section 1.20(b)) or issued Valid Claim (i.e.,
     as defined in Section 1.30(ii)) within the Collaboration Technology which
     but for the licenses granted herein by Array to ICOS, would infringe a
     Valid Claim within Patents within the Collaboration Technology.

          (d) ICOS may reduce the percentage amount of earned royalties payable
     for a Product under this Agreement by [***] the amount in excess of [***]
     that ICOS elects or is required,

                                  -14.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

     in its reasonable business judgement, to pay to Third Parties who are not
     Affiliates or Sublicensees of ICOS in order to sell such Product and to
     avoid or settle a patent infringement action; provided, however, that the
     royalties payable by ICOS to Array for the sale of Product shall not be
     reduced to less than [***] the amount that ICOS would otherwise be
     obligated to pay to Array; and further provided that if ICOS sells [***]
     Products with the same active ingredient in the same country, then the
     maximum percentage amount royalty reduction for such same country allowable
     under this Section 5.4(d) for [***] Product shall not exceed [***] under
     this Section for [***] Product, if such Product were sold alone.

     5.5 Third Party Royalties. ICOS shall be responsible for all payments due
to Third Parties for the manufacture, use, or sale of Products by ICOS, its
Affiliates or Sublicensees.

                                    ARTICLE 6
                           PAYMENTS; BOOKS AND RECORDS

     6.1 Payments.

          (a) Royalty Reports. ICOS shall deliver to Array within sixty (60)
     days after the last day of each calendar quarter in which Products are
     sold, a report setting forth in reasonable detail the calculation of the
     royalties payable to Array for such calendar quarter identifying, by
     country and Product, the Products sold by ICOS and its Affiliates and
     Sublicensees, and the calculation of Net Sales and royalties due to Array.

          (b) Timing of Royalty Payments. All royalties due to Array shall be
     paid within [***] days after the last day of the calendar quarter in which
     they accrue.

          (c) Payment Method. Except as expressly stated elsewhere in this
     Agreement, all payments due under this Agreement shall be paid within [***]
     days from the date such payments become due and owing and made from a bank
     located in the United States by bank wire transfer in immediately available
     funds to a bank account designated by Array. All payments hereunder shall
     be made in U.S. dollars. In the event that the due date of any payment
     subject to Article 5 hereof is a Saturday, Sunday or national holiday, such
     payment may be paid on the following business day. Any payments that are
     not paid on the date such payments are due under this Agreement shall bear
     interest to the extent permitted by applicable law at the prime rate as
     reported by the Chase Manhattan Bank, New York, New York, on the date such
     payment is due, plus an additional one percent (1%), calculated on the
     number of days such payment is delinquent.

          (d) Currency Conversion. If any currency conversion shall be required
     in connection with the calculation of amounts payable hereunder, such
     conversion shall be made using the buying exchange rate for conversion of
     the foreign currency into U.S. dollars, quoted for current transactions
     reported in The Wall Street Journal for the last business day of the
     calendar quarter to

                                  -15.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

     which such payment pertains, except in the case of withholding taxes under
     6.3, the applicable calendar quarter shall be that calendar quarter for
     payments upon which such taxes were levied.

     6.2 Records; Inspection. ICOS and its Affiliates and Sublicensees shall
keep complete, true and accurate books of account and records for the purpose of
determining the milestone amounts payable under this Agreement. Such books and
records shall be kept at the principal place of business of such party, as the
case may be, for at least three (3) years following the end of the calendar
quarter to which they pertain. Such records will be open for inspection during
such three (3) year period by an independent public accounting firm to whom ICOS
or its Affiliates and Sublicensees have no reasonable objection, solely for the
purpose of verifying milestone statements hereunder. Such inspections may be
made no more than once each calendar year, at reasonable times and on reasonable
notice. The independent auditor shall be obligated to execute a reasonable
confidentiality agreement prior to commencing any such inspection. Inspections
conducted under this Section 6.2 shall be at the expense of Array, unless a
variation or error producing an increase in payment to Array of greater than
five percent (5%) per annum for any period covered by the inspection is
established in the course of any such inspection, whereupon all reasonable costs
relating to the inspection for such period and any unpaid amounts that are
discovered will be paid promptly by ICOS to Array together with interest thereon
from the date such payments were due at the lesser of the prime rate as reported
by the Chase Manhattan Bank, New York, New York, plus an additional one percent
(1%) or the maximum rate permitted by law if less. The interest available to
Array pursuant to this Section 6.2 shall in no way limit any other remedies
available to Array.

     6.3 Withholding Taxes. All FTE payments, milestone payments and other fees
required to be paid to Array pursuant to this Agreement shall be paid without
deduction for withholding for or on account of any taxes (other than taxes
imposed on or measured by net income) or similar governmental charge imposed by
a jurisdiction other than the United States ("Withholding Taxes"), which ICOS
agrees to pay separately; provided, however, to the extent Array and/or its
Affiliates or their successors utilizes the Withholding Taxes paid by ICOS as a
credit to reduce Array's and/or its Affiliates regular U.S. tax liability, then
Array shall repay to ICOS the amount of such reduction. ICOS shall provide Array
a certificate evidencing payment of any Withholding Taxes hereunder.

                                    ARTICLE 7
                                  DUE DILIGENCE

     To the extent it is reasonably commercially prudent to do so, for each Drug
Development Candidate and Product to which ICOS retains rights under this
Agreement, ICOS shall use commercially reasonable efforts, consistent with ICOS'
reasonable business judgment, to develop and commercialize such Drug Development
Candidates and Products, and to obtain reasonable commerical return for each
Drug Development Candidate, consistent with professional standards for the
development, commercialization and marketing of pharmaceutical products of
similar commercial value potential.

                                  -16.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS
<PAGE>

                                    ARTICLE 8
                              INTELLECTUAL PROPERTY

     8.1 Ownership of Inventions. Inventorship shall be decided according to
U.S. Patent Law. Notwithstanding the foregoing: (a) title to all Collaboration
Technology made solely by ICOS personnel shall be owned by ICOS; (b) title to
all Collaboration Technology made solely by Array personnel shall be owned by
Array, and (c) title to all Collaboration Technology made jointly by personnel
of ICOS and Array shall be jointly owned by ICOS and Array. Except as expressly
provided in this Agreement, it is understood that neither Party shall have any
obligation to account to the other for profits, or to obtain any approval of the
other Party to license or exploit a joint invention, by reason of joint
ownership of any invention or other intellectual property.

     8.2 Prosecution. ICOS shall have the first right to pursue the preparation,
filing, prosecution and maintenance of any patent applications, patents or other
intellectual property rights within the Collaboration Technology. ICOS shall
keep Array fully informed as to the status of patent matters concerning
Collaboration Technology described in 8.1(b) and (c) herein and described in
this Section 8.2, including without limitation, by providing Array copies of any
substantive documents that ICOS receives from any patent office promptly after
receipt, including notice of all interferences, reissues, re-examinations,
oppositions or requests for patent term extensions, and by providing Array the
opportunity, as far in advance of filing dates as possible, to fully review and
comment on any documents which will be filed in any patent office, and
incorporating all reasonable comments; provided, however, that ICOS shall have
the right to make all final decisions with respect to the prosecution of subject
matter within the Field. Array shall reasonably cooperate with and assist ICOS
in connection with such activities, at ICOS's request, including without
limitation by making scientists and scientific records reasonably available to
ICOS. In the event ICOS fails or declines to take such actions with respect to
any inventions concerning Collaboration Technology described in 8.1(b) and (c)
herein and in accordance with this Section 8.2, then Array shall have the right
to file, prosecute and maintain such patent applications or patents at its sole
expense(subject to the licenses granted to ICOS under this Agreement). ICOS
shall notify Array at least sixty (60) days, or as soon as practicable to
prevent impairment of any rights Array has or may acquire by ICOS acting or
failing to act, prior to the date the next necessary action or filing is due to
be taken which could impair any rights Array has or may acquire by such action,
inaction or filing with respect to any invention concerning Collaboration
Technology described in Section 8.1(b) or (c) above, or any patent or patent
application claiming such invention.

                                    ARTICLE 9
                            CONFIDENTIAL INFORMATION

     9.1 Nondisclosure. Except as expressly provided herein, the receiving party
(hereinafter, the "Receiving Party") shall not disclose to any third party or
use for any purpose any Confidential Information furnished to it by the other
party (hereinafter the "Disclosing Party") pursuant to this

                                  -17.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS
<PAGE>

Agreement. With respect to information generated in the course of the Research
Collaboration, such information shall not be deemed confidential, or
Confidential Information hereunder, as to ICOS.

     9.2 Permitted Use and Disclosures. The Receiving Party may use and disclose
the Confidential Information of the Disclosing Party to the extent necessary to
exercise its rights or perform its obligations under this Agreement, in filing
or prosecuting applications and patents, prosecuting or defending litigation,
complying with applicable governmental regulations or court order or otherwise
submitting information to tax or other governmental authorities, conducting
trials, or making a permitted sublicense or otherwise exercising license rights
expressly granted to the other party to it pursuant to the terms of this
Agreement, provided that if the Receiving Party is required to make any such
disclosures of the Disclosing Party's Confidential Information, other than
pursuant to a confidentiality agreement it shall, where allowed by law, give
reasonable advance notice the Disclosing Party of such disclosure and, save to
the extent inappropriate in the case of patent applications, shall use
reasonable efforts to secure confidential treatment of such Confidential
Information in consultation with the Disclosing Party prior to its disclosure
(whether through protective orders or otherwise) and disclosure only that
portion of the Confidential Information necessary to comply with such
requirements.

     9.3 Nondisclosure of Terms. Each of the Parties hereto agrees not to
disclose the terms of this Agreement to any Third Party without the prior
written consent of the other Party hereto, which consent shall not be
unreasonably withheld, except to such Party's attorneys, advisors, investors and
others on a need to know basis under circumstances that reasonably ensure the
confidentiality thereof, or to the extent required by law. Notwithstanding the
foregoing, the Parties shall agree upon a joint press release and timing to
announce the execution of this Agreement thereafter, Array and ICOS may each
disclose to Third Parties the information contained in such press release
without the need for further approval by the other. In addition, ICOS and Array
may make public statements regarding the progress of the Research Collaboration
and the achievement of milestones and fees with respect thereto, following
consultation and mutual agreement, the consent of neither Party to be
unreasonably withheld.

     9.4 Publication. Any manuscript by Array or ICOS describing the scientific
results of the Research Collaboration to be published during the Research Term
or within [***] after the end of the Research Term shall be subject to the prior
review of the Parties at least [***] days prior to submission. Further, to avoid
loss of patent rights arising under 8.1(b) and (c) herein as a result of
premature public disclosure of patentable information, the Party proposing to
disclose or publish technology arising under 8.1(b) and (c) herein (the
"Publishing Party") shall provide the other Party (the "Reviewing Party") with a
copy of the proposed disclosure at least [***] days prior to the date of the
proposed disclosure. The Reviewing Party shall notify the Publishing Party in
writing within [***] days after receipt of any proposed disclosure whether the
Reviewing Party desires to file a patent application on any invention disclosed
in such scientific results. In the event that the Reviewing Party desires to
file such a patent application, the Publishing Party shall withhold publication
or disclosure of such scientific results until the earlier of (i) a patent
application is filed

                                  -18.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS
<PAGE>

thereon, or (ii) the Parties determine after consultation that no patentable
invention exists, or (iii) [***] days after receipt by the Publishing Party of
the Reviewing Party's written notice of the Reviewing Party's desire to file
such patent application, or such other period as is reasonable for seeking
patent protection. Further, if such scientific results contain the information
of the Reviewing Party that is subject to use and nondisclosure restrictions
under this Article 9, the Publishing Party agrees to remove such information
from the proposed publication or disclosure. Following the filing of any patent
application within the Collaboration Technology, in the eighteen (18) month
period prior to the publication of such a patent application, neither Party
shall make any written public disclosure regarding any invention claimed in such
patent application without the prior consent of the other Party.

                                   ARTICLE 10
                         REPRESENTATIONS AND WARRANTIES

     10.1 ICOS. ICOS represents and warrants on its own behalf and on behalf of
its Affiliates that: (i) it has the full right and authority to enter into this
Agreement and to grant the rights and licenses herein, and (ii) to its knowledge
and belief, no action, suit or claim has been initiated or threatened against
ICOS with respect to its right to enter into and perform its obligations under
this Agreement.

     10.2 Array. Array represents and warrants that: (i) it has the full right
and authority to enter into this Agreement and to grant the rights and licenses
herein, and (ii) to its knowledge and belief, no action, suit or claim has been
initiated or threatened against Array with respect to its right to enter into
and perform its obligations under this Agreement.

     10.3 Disclaimer. ICOS and Array specifically disclaim any representation,
warranty or guarantee that the Research Program will be successful, in whole or
in part. The failure of the parties to successfully develop a Drug Development
Candidate will not constitute a breach of any representation or warranty or
other obligation under this Agreement. EXCEPT AS OTHERWISE EXPRESSLY SET FORTH
IN THIS AGREEMENT, ARRAY AND ICOS EXPRESSLY DISCLAIM ANY WARRANTIES OR
CONDITIONS, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, WITH RESPECT TO THE
RESEARCH PROGRAM, THE PROCESSES TO BE DEVELOPED OR THE COMPOUNDS TO BE
SYNTHESIZED HEREUNDER, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, VALIDITY OF ANY LICENSED
TECHNOLOGY, PATENTED OR UNPATENTED, OR NONINFRINGEMENT OF THE INTELLECTUAL
PROPERTY RIGHTS OF THIRD PARTIES.

                                   ARTICLE 11
                                 INDEMNIFICATION

                                  -19.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>
     11.1 Product Liability. ICOS hereby agrees to save, defend and hold Array
and its officers, directors, employees, consultants, and agents harmless from
and against any and all suits, claims, actions, demands, liabilities, expenses
and losses, including reasonable legal expenses and attorneys' fees ("Losses")
resulting directly or indirectly from any claim alleging physical injury or
death or otherwise arising out of the administration, utilization and/or
ingestion of Products based on Compounds synthesized by Array hereunder that are
manufactured, used or sold by or under the authority of ICOS, its Affiliates or
Sublicensees except to the extent such Losses result from the negligence, breach
of this Agreement or willful misconduct of Array.

     11.2 Procedures. If Array (the "Indemnified Party") seeks indemnification
under this Article 11, it shall inform ICOS (the "Indemnifying Party") of a
claim as soon as reasonably practicable after it receives notice of the claim,
shall permit the Indemnifying Party to assume direction and control of the
defense of the claim (including the right to settle any claim brought against
the Indemnified Party upon prior written consent, which shall not be
unreasonably withheld), and shall give reasonable cooperation (at the expense of
the Indemnifying Party) in the defense of such claim.

                                   ARTICLE 12
                              TERM AND TERMINATION

     12.1 Term. Unless earlier terminated pursuant to the other provisions of
this Article 12, this Agreement shall continue in full force and effect on a
country-by-country and Product-by- Product basis until the end of the royalty
term set forth in Section 5.4(c).

     12.2 Permissive Termination. ICOS shall have the right to terminate this
Agreement upon [***] written notice to Array; provided that such notice shall
not be [***].

     12.3 Termination for Breach. Either Party to this Agreement may terminate
this Agreement in the event the other Party has materially breached this
Agreement and does not cure such breach within [***] days after written notice
thereof (reasonably identifying the breach) was provided to the breaching Party
by the nonbreaching Party. Any termination shall become effective at the end of
such [***] day period unless the breaching Party has cured or acted materially
to cure any such breach or default prior to the expiration of the [***] day
period.

                                  -20.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

     12.4 Effect of Expiration or Termination.

          (a) Accrued Rights and Obligations. Termination of this Agreement for
     any reason shall not release any Party hereto from any liability which, at
     the time of such termination, has already accrued to the other Party or
     which is attributable to a period prior to such termination, nor preclude
     either Party from pursuing any rights and remedies it may have hereunder or
     at law or in equity which accrued or are based upon any event occurring
     prior to such termination.

          (b) Survival. Articles 1 (to the extent referenced in any of the
     following Articles or Sections), 5, 7, 9, 11 and 13 of this Agreement, as
     well as Section 2.9 shall survive the expiration or termination of this
     Agreement for any reason.

                                   ARTICLE 13
                                  ASSIGNABILITY

     13.1 Generally. This Agreement may not be assigned by either Party without
the prior written consent of the other Party, and which shall not to be
unreasonably withheld; provided, however, that either Party may assign this
Agreement, in whole or in part, to an Affiliate or to a successor of a Party in
connection with the merger, consolidation or sale of all or substantially all of
such Party's assets or that portion of its business pertaining to the subject
matter of this Agreement (and upon doing so will promptly notify the other Party
in writing) (each such transaction being referred to as an "Acquisition");
provided that the assigning Party remains fully liable as obligated hereunder.

     Notwithstanding the foregoing, ICOS shall have the right to assign its
rights, duties and obligations under this Agreement to a company or organization
in which it owns at least a fifty percent (50%) of the outstanding shares or
other voting rights of such company or organization having the power to vote on
or direct the affairs of the company or organization. In the event of such an
assignment, ICOS shall not be released, remised or discharged from any
obligations or covenants without the prior written consent of Array.
Notwithstanding the foregoing, in the event Array so consents to ICOS's release,
the company or organization, as the case may be, to which ICOS assigns this
Agreement shall execute a written agreement providing that such company or
orgainzation shall assume all such obligations or covenants from ICOS.

     13.2 Technology of Acquirer. In the event of an Acquisition, it is
understood and agreed that no intellectual property rights or technology of the
acquirer shall be included within the subject matter licensed hereunder, to the
extent that such intellectual property or technology was owned or controlled by
the acquirer as of the date of the Acquisition, or was created or obtained after
the date of the Acquisition other than by former employees of Array in the
course of performing the Research Program.

                                  -21.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS
<PAGE>

                                   ARTICLE 14
                          DISPUTE RESOLUTION PROCEDURES

     14.1 Senior Executives Discussions. If a dispute arises between Array and
ICOS or with respect to matters other than the management of the Research
Program, either during or after the Research Term, such dispute will be referred
to the appropriate senior management concerning the subject matter of the
dispute. If such senior management are unable to resolve such dispute, such
dispute will be referred to the Executive Vice President of Operations of ICOS
and the Chief Operating Officer of Array.

     14.2 Injunctive Relief. Nothing contained in this Section 14 or any other
provisions of this Agreement shall be construed to limit or preclude a Party
from bringing any action in any court of competent jurisdiction seeking
injunctive or other relief or seeking to compel the other Party to comply or
specifically perform with its obligations hereunder.

                                   ARTICLE 15
                                  MISCELLANEOUS

     15.1 Governing Laws. This Agreement and any dispute arising from the
performance or breach hereof shall be governed by and construed and enforced in
accordance with, the laws of the state of Washington, without reference to
conflicts of laws principles.

     15.2 Waiver. Waiver by either Party or the failure by either Party to claim
a breach of any provision of this Agreement shall not be deemed to constitute a
waiver or estoppel with respect to any subsequent breach of any provision
hereof.

     15.3 Independent Contractors. The relationship of the parties hereto is
that of independent contractors. The parties hereto are not deemed to be agents,
partners or joint venturers of the others for any purpose as a result of this
Agreement or the transactions contemplated thereby.

     15.4 Compliance with Laws. In exercising their rights under this Agreement,
the parties shall fully comply in all material respects with the requirements of
any and all applicable laws, regulations, rules and orders of any governmental
body having jurisdiction over the exercise of rights under this Agreement
including, without limitation, those applicable to the discovery, development,
manufacture, distribution, import and export and sale of pharmaceutical products
pursuant to this Agreement.

     15.5 Notices. Any notice required or permitted to be given hereunder shall
be deemed sufficient if sent by facsimile letter or overnight courier, or
delivered by hand to ICOS or Array at the respective addresses and facsimile
numbers as set forth below or at such other address and facsimile number as
either Party hereto may designate. If sent by facsimile letter, notice shall be
deemed given when the transmission is completed if the sender has a confirmed
transmission report. If a confirmed

                                  -22.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

transmission report does not exist, then the notice will be deemed given when
the notice is actually received by the person to whom it is sent. If delivered
by overnight courier, notice shall be deemed given when it has been signed for.
If delivered by hand, notice shall be deemed given when received.

                  if to Array, to:          Array BioPharma Corporation
                                            1885 33rd Street
                                            Boulder, Colorado 80301
                                            Attention: Chief Operating Officer
                                            Fax number: (303) 381-6697

                  with a copy to:           Wilson Sonsini Goodrich & Rosati
                                            650 Page Mill Road
                                            Palo Alto, CA 94304
                                            Attention: Kenneth A. Clark
                                            Fax number: (650) 493-6811

                  if to ICOS, to:           ICOS Corporation
                                            22021 20th Avenue S.E.
                                            Bothell, WA  98021
                                            Attention: Legal Department
                                            Fax number: 425/398-8950

     15.6 Severability. In the event that any provision of this Agreement
becomes or is declared by a court of competent jurisdiction to be illegal,
unenforceable or void, this Agreement shall continue in full force and effect to
the fullest extent permitted by law without said provision, and the parties
shall amend the Agreement to the extent feasible to lawfully include the
substance of the excluded term to as fully as possible realize the intent of the
parties and their commercial bargain.

     15.7 Force Majeure. Neither Party shall lose any rights hereunder or be
liable to the other Party for damages or losses (except for payment obligations)
on account of failure of performance by the defaulting Party if the failure is
occasioned by war, strike, fire, Act of God, earthquake, flood, lockout,
embargo, governmental acts or orders or restrictions, failure of suppliers, or
any other reason where failure to perform is beyond the reasonable control, and
not caused by the negligence, intentional conduct or misconduct, of the
nonperforming Party and the non-performing Party has exerted all reasonable
efforts to avoid or remedy such force majeure; provided, however, that in no
event shall a Party be required to settle any labor dispute or disturbance.

     15.8 Complete Agreement. This Agreement represents the entire agreement of
the parties with respect to the subject matter hereof and supersedes all prior
understandings and agreements with respect thereto. No change or modification of
the provisions of this Agreement shall be effective unless it is in writing and
signed by a duly authorized officer of Array and ICOS.

                                  -23.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

     14.9 Headings. The headings and numbering herein are not a part of this
Agreement, but are included merely for convenience of reference only and shall
not affect its meaning or interpretation.

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

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed by their authorized representatives as of the Effective Date.

<TABLE>
<CAPTION>
ARRAY BIOPHARMA, INC.                                        ICOS CORPORATION
<S>                                                          <C>
By:                                                           By:
   --------------------------------------------------            --------------------------------------------------

Name:                                                         Name:    W. Michael Gallatin, Ph.D.
     ------------------------------------------------              ------------------------------------------------

Title:                                                        Title:   Vice President and Scientific Director
      -----------------------------------------------              ------------------------------------------------

</TABLE>

                                  -24.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS
<PAGE>

                                    EXHIBIT A

                            DRUG DEVELOPMENT TARGETS

[***]

                                  -25.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

                                    EXHIBIT B

                                     EUROPE

                    Albania                                    Lithuania
                    Andorra                                    Luxembourg
                    Armenia                                    Macedonia
                    Austria                                    Malta
                    Azerbaijan                                 Moldova
                    Belarus                                    Monaco
                    Belgium                                    Montenegro
                    Bosnia and Herzegovina                     Netherlands
                    Bulgaria                                   Norway
                    Croatia                                    Poland
                    Cypress                                    Portugal
                    Czech Republic                             Romania
                    Denmark                                    Russia
                    Estonia                                    San Marino
                    Finland                                    Serbia
                    France                                     Slovakia
                    Georgia                                    Slovenia
                    Germany                                    Spain
                    Greece                                     Sweden
                    Hungary                                    Switzerland
                    Iceland                                    Turkey
                    Ireland                                    Ukraine
                    Italy                                      United Kingdom
                    Latvia                                     Vatican City
                    Liechtenstein

                                  -26.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

<PAGE>

                                    EXHIBIT C

                       DRUG DEVELOPMENT CANDIDATE CRITERIA

         [***]

                                  -27.              [***] CONFIDENTIAL TREATMENT
                                         HAS BEEN REQUESTED OF REDACTED PORTIONS

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