Document:

<Page>

                                                                   Exhibit 10.39

                             COLLABORATION AGREEMENT

PFIZER INC, a Delaware corporation, having an office at 235 East 42nd Street,
New York, New York 10017 and its Affiliates ("Pfizer"), and ARQULE INC., a
Delaware corporation, having an office at 19 Presidential Way, Woburn, MA
01801-5140 and its Affiliates ("ArQule"), enter into this Collaboration
Agreement as of December 19, 2001 ("Effective Date") to design, synthesize and
provide Pfizer with pharmacologically relevant compounds, suited for
incorporation into Pfizer's screening file, together with related materials and
information, on the terms and subject to the conditions set forth herein. This
Agreement shall supercede the Technology Acquisition Agreement between Pfizer
and ArQule dated as of July 19, 1999 ("1999 Agreement"), which 1999 Agreement
shall terminate and be of no further force or effect as of the Effective Date.

1.   DEFINITIONS. Whenever used in this Agreement, the terms defined in this
     Section 1 shall have the meanings so specified.

     1.1   "AFFILIATE" means any corporation or other legal entity owning,
           directly or indirectly, fifty percent (50%) or more of the voting
           capital shares or similar voting securities of Pfizer or ArQule; any
           corporation or other legal entity fifty percent (50%) or more of the
           voting capital shares or similar voting rights of which is owned,
           directly or indirectly, by Pfizer or ArQule; or any corporation or
           other legal entity fifty percent (50%) or more of the voting capital
           shares or similar voting rights of which is owned, directly or
           indirectly, by a corporation or other legal entity which owns,
           directly or indirectly, fifty percent (50%) or more of the voting
           capital shares or similar voting securities of Pfizer or ArQule.

     1.2   "AGREEMENT PERIOD" means the period beginning on the Effective Date
           and ending seven (7) years later, unless terminated earlier pursuant
           to Section 8.

     1.3   "AMAP SYSTEM" means the AMAP-TM- Parallel Synthesis System described
            in Exhibit A and located at ArQule's Medford, MA production facility
           ("Medford"), that functions as a combinatorial chemistry synthesis
           platform comprising *.

     1.4   "ArQULE CONFIDENTIAL INFORMATION" means all information about any
           element of the ArQule Technology which is disclosed by ArQule to
           Pfizer, and designated "Confidential" in writing by ArQule at the
           time of disclosure or within thirty (30) days following disclosure.

     1.5   "ArQULE DESIGN TOOLS" means the design tools and informatics systems
           described on and made part of this Agreement as Exhibit B.

     1.6   "ArQULE TECHNOLOGY" means all Related Technology (including but not
           limited to ArQule's AMAP-TM- Parallel Synthesis System and ArQule
           Design Tools), which is or was developed by employees of or
           consultants to ArQule alone or jointly with third parties prior to
           the Effective Date, or acquired by purchase, license, assignment or
           other means from third parties by ArQule prior to the Effective Date;
           and improvements related solely to the foregoing.

           [*]=CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED
           SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN
           REQUESTED WITH RESPECT TO THE OMITTED PORTIONS. OMITTED TEXT IS
           INDICATED BY A "*".

<Page>

                                        2

           Notwithstanding the foregoing, ArQule Technology shall not include
           any Related Technology that ArQule does not have the right to
           license, sublicense, or practice without the consent of or payment to
           a third party.

     1.7   "CALENDAR QUARTER" means any calendar quarter during the Agreement
           Period, provided, however, that the first Calendar Quarter of the
           Agreement shall mean the time period including any remaining days in
           2001 on and following the Effective Date and the first calendar
           quarter in 2002.

     1.8   "COLLABORATION PROGRAM" is the program to produce Pfizer Compounds as
           conducted by Pfizer and ArQule pursuant to the Project Plan.

     1.9   "LIBRARY PROTOCOLS" means *.

     1.10  "PARTY" means ArQule or Pfizer, and "PARTIES" means ArQule and
           Pfizer.

     1.11  "PFIZER COMPOUNDS" means the *, pursuant to the Collaboration
           Program, and all *.

     1.12  "PFIZER CONFIDENTIAL INFORMATION" means all information about any
           element of Pfizer Technology which is disclosed by Pfizer to ArQule
           and designated "Confidential" in writing by Pfizer at the time of
           disclosure or within thirty (30) days following disclosure.

     1.13  "PFIZER TECHNOLOGY" means all Related Technology that is or was
           developed by employees of or consultants to Pfizer alone or jointly
           with third parties prior to the Effective Date, or acquired by
           purchase, license, assignment or other means from third parties by
           Pfizer prior to the Effective Date; and improvements related solely
           to the foregoing.

           Notwithstanding the foregoing, Pfizer Technology shall not include
           any Related Technology that Pfizer does not have the right to
           license, sublicense, or practice without the consent of or payment to
           a third party.

     1.14  *.

     1.15  "PROGRAM TECHNOLOGY" means all Related Technology that is or was:

           a.    developed by employees of or consultants to ArQule or Pfizer
                 solely or jointly in the course of performing the Collaboration
                 Program; and

           b.    acquired by purchase, license, assignment or other means from
                 third parties by either of the Parties in the course of
                 performing the Collaboration Program; and

           c.    improvements related solely to the foregoing.

           Program Technology shall not include Pfizer Compounds.
<Page>

                                        3

     1.16  "PROJECT PLAN" means the written plan describing the Collaboration
           Program to be carried out by Pfizer and ArQule pursuant to this
           Agreement for the Agreement Period, attached to and made a part of
           this Agreement as Exhibit C.

     1.17  "PRODUCTION GOALS" mean *.

     1.18  "RELATED TECHNOLOGY" means and includes, solely to the extent
           relating to the Collaboration Program, all data, materials, specific
           chemical compounds and intermediates thereof, synthetic and
           manufacturing procedures, technical and non-technical information,
           know-how, expertise and trade secrets.

2.   COLLABORATION PROGRAM.

     2.1   PURPOSE. ArQule and Pfizer shall diligently conduct the Collaboration
           Program throughout the Agreement Period in accordance with the
           Project Plan.

     2.2   PROJECT PLAN. The Steering Committee shall review and amend, if
           necessary, the Project Plan. Any amendments to the Project Plan shall
           be appended to Exhibit C and made part of this Agreement.

     2.3   PRODUCTION GOALS.

           a.    ArQule shall use reasonably diligent efforts to achieve all
                 Production Goals during the Agreement Period. For purposes of
                 determining satisfaction of Production Goals, "Pfizer
                 Compounds" shall mean only those compounds produced pursuant to
                 the Collaboration Program.

           b.    Compounds produced during the Agreement Period that fail to
                 satisfy the specifications identified in the Project Plan will
                 not count towards ArQule's Production Goals and, subject to the
                 cure provision set forth in Section 4.1(b), ArQule will destroy
                 any such compounds, unless Pfizer notifies ArQule to the
                 contrary in writing, within thirty (30) days of the end of the
                 Calendar Quarter in which such compounds were produced.

           c.    Pfizer shall have the right to * Pfizer Compounds in the
                 Production Goals anytime after the * anniversary of the
                 Effective Date, by delivering * prior written notice to ArQule,
                 provided that (i) in no event may Pfizer decrease the number of
                 Pfizer Compounds in the Production Goals below * Pfizer
                 Compounds per calendar year, (ii) no decrease may exceed a *
                 Pfizer Compound total decrease in any calendar year, and (iii)
                 the amount and timing of any increase shall be agreed upon by
                 the Steering Committee.

     2.4   STEERING COMMITTEE. Pfizer and ArQule shall direct the Collaboration
           Program via the Steering Committee (the "Steering Committee"), which
           shall perform the following duties in good faith:

           a.    Consistent with Section 2.2, prepare the Project Plan and any
                 amendments;

           b.    Review and evaluate progress under the Project Plan and report
                 to Pfizer the completion of Production Goals;

<Page>

                                        4

           c.    Approve, coordinate and monitor activities and staffing;

           d.    Approve, coordinate and monitor Technology deliveries between
                 the Parties;

           e.    Coordinate and monitor * ;

           f.    Establish, implement and manage a series of operational
                 guidelines;

           g.    *;

           h.    Coordinate and monitor publication of Program Technology
                 developed during the Agreement Period pursuant to Section 5.2.
                 This function shall survive termination of this Agreement;

           i.    Serve as an initial forum for the Parties to resolve disputes,
                 pursuant to Section 13; and

           j.    Establish and appoint work groups.

           The Steering Committee may have other duties as mutually agreed.

     2.5   MEMBERSHIP. Pfizer and ArQule each shall appoint, in its sole
           discretion, four (4) members to the Steering Committee. Subject to
           Section 2.13, substitutes may be appointed at any time.

           Pfizer Appointees: *

           ArQule Appointees: *

     2.6   CHAIR. The Steering Committee shall be chaired by two
           co-chairpersons, one appointed by Pfizer and the other appointed by
           ArQule.

     2.7   MEETINGS. The Steering Committee shall meet at least quarterly, at
           places selected by each Party in turn and on dates mutually agreed by
           the Parties. Representatives of Pfizer or ArQule or both, in addition
           to members of the Steering Committee, may attend such meetings at the
           invitation and expense of that Party.

     2.8   MINUTES. The Party hosting the meeting shall be responsible for the
           preparation and circulation of the draft minutes. Draft minutes
           shall be edited by the co-chairperson and shall be issued in final
           form only with the approval and agreement of the Steering Committee.

     2.9   DECISIONS. All decisions of the Steering Committee shall be made
           by *.

<Page>

                                        5

     2.10  EXPENSES. Pfizer and ArQule shall each bear all expenses, including
           reasonable travel, related to the participation of its respective
           representatives and members of the Steering Committee.

     2.11  REPORTS. During the Agreement Period, each work group established by
           the Steering Committee shall furnish to the Steering Committee
           summary written reports within such work group's purview within *
           days after the end of each Calendar Quarter commencing on the
           Effective Date, describing *.

     2.12  LABORATORY FACILITIES AND PERSONNEL. Each Party shall provide
           suitable laboratory facilities, equipment and personnel for the work
           to be done by it in carrying out the Collaboration Program.

     2.13  KEY INVESTIGATORS. During the Agreement Period * ("Key
           Investigators") shall serve on the Steering Committee and shall be
           solely responsible for preventing ArQule from working with any Pfizer
           Compound outside the Collaboration Program. During such period, *
           shall commit approximately * percent (*%) and * percent (*%),
           respectively, of their time each week to the Collaboration Program.
           In the event either Key Investigator leaves ArQule, ArQule shall
           propose to Pfizer a replacement Key Investigator with credentials
           substantially similar to or stronger than the departing Key
           Investigator. Pfizer shall review and approve the proposed
           replacement Key Investigator, which such approval shall not be
           unreasonably withheld, conditioned or delayed.

3.   OTHER PROGRAMS.

     3.1   CAMITRO TOOLS: Pfizer shall consider entering into a license
           agreement with ArQule to obtain the Camitro predictive adsorption and
           metabolism in vitro predictive model tools. In the event Pfizer
           elects to enter into such an agreement, the Parties shall negotiate
           in good faith the terms and conditions of such license in a separate
           agreement.

     3.2   LEAD OPTIMIZATION: Pfizer shall propose to ArQule at least one (1)
           lead optimization program, the subject matter of which shall *, on
           which it will collaborate with ArQule during the Agreement Period.
           The Parties shall negotiate in good faith the terms and conditions of
           such lead optimization program in a separate agreement.

4.   PAYMENTS AND RESPONSIBILITIES.

     4.1   AMAP SYSTEM. In consideration of the transfer to Pfizer of all of
           ArQule's right, title and interest in and to the AMAP System
           pursuant to the 1999 Agreement and that certain Certificate of
           Ownership dated January 3, 2000, attached hereto as Exhibit D, and,
           subject to Section 8.4, the grant to Pfizer of a * license to *, the
           ArQule Confidential Information and ArQule Technology related solely
           thereto pursuant to Section 6.2(a), Pfizer will make payments to
           ArQule according to the following:

           a.    QUARTERLY INSTALLMENTS: For *, beginning on the Effective Date,
                 Pfizer will pay to ArQule quarterly installments, in advance,
                 of * dollars ($*) for a

<Page>

                                        6

                 total of * dollars ($*). Pfizer will pay such installments
                 within * after receipt of ArQule's invoice.

           b.    SUCCESS PAYMENT: If the Steering Committee determines that
                 ArQule met its quarterly Production Goals for the two years
                 following the Effective Date, Pfizer shall pay to ArQule an
                 additional amount of up to * dollars ($*) in quarterly
                 installments (each a "Success Payment") as set forth in Exhibit
                 E. Each Success Payment will be paid quarterly as follows:
                 (i) if fewer than *. Notwithstanding the foregoing, ArQule may
                 cure any shortfalls in achieving the Production Goals for any
                 Calendar Quarter in the next Calendar Quarter. To the extent *.

           c.    *: For *, beginning on the Effective Date, Pfizer will pay
                 quarterly installments, in advance, of * dollars ($*) for *.
                 Pfizer will pay such installments within * after receipt of
                 ArQule's invoice.

     4.2   DESIGN TOOLS: In consideration of ArQule's grant to Pfizer of a
           license to the ArQule Design Tools, as provided in Section 6.2(a),
           Pfizer will pay to ArQule a license fee of up to * dollars ($*). Such
           license fee shall be paid in * installments, in advance, of * dollars
           ($*) for the first * of the Agreement Period. Thereafter, Pfizer
           shall pay * dollars ($*) per *, in advance, for the next *. If Pfizer
           terminates pursuant to Section 8.3(a) then Pfizer shall have no
           further obligation to make payments under this Section 4.2.

     4.3   COLLABORATION PROGRAM FUNDING. Pfizer shall pay for * according to
           the annual payment schedule ("Payment Schedule") attached to and made
           part of this Agreement as Exhibit F.

           a.    Pfizer shall pay to ArQule a nonrefundable amount equal to *
                 quarterly, in advance, for work scheduled to be performed by
                 ArQule pursuant to the Project Plan. The * for that Calendar
                 Quarter shall be paid upon delivery of Pfizer Compounds if: (i)
                 *. Pfizer will pay ArQule the quarterly installment of * within
                 * of receipt of ArQule's invoice. Notwithstanding the
                 foregoing, ArQule may cure any shortfalls in achieving the
                 Production Goals for any Calendar Quarter in the next Calendar
                 Quarter. To the extent ArQule *.

           b.    In the event that Pfizer changes the annual number of Pfizer
                 Compounds in the Production Goals consistent with Section
                 2.3(c), the Parties will adjust the payments made by Pfizer
                 under this Section 4.3 in each year in which Production Goals
                 are amended in order to obtain an average Compound Cost of *
                 dollars ($*) over the Agreement Period.

     4.4   OTHER PAYMENTS.

           a.    REMAINING LEASE PAYMENTS AT MEDFORD. For the * period
                 concluding on the *, Pfizer shall pay ArQule quarterly, in
                 advance, * dollars ($*) per Calendar Quarter for the sublease
                 of the facility.

           b.    EQUITY PURCHASE.

<Page>

                                       7

                 (i)   Concurrently with the execution of this Agreement, Pfizer
                       shall make an equity investment in ArQule of
                       approximately ten million dollars ($10,000,000) of ArQule
                       common stock at a purchase price of $* per share * in
                       accordance with the terms and conditions of the Equity
                       Purchase Agreement between Pfizer and ArQule of even date
                       herewith attached to and made part of this Agreement as
                       Exhibit G.

                 (ii)  If ArQule meets the Production Goals as determined by the
                       Steering Committee for the first year of the
                       Collaboration Program to produce * Pfizer Compounds,
                       then, within * of the first anniversary of the Effective
                       Date, Pfizer shall make an additional equity investment
                       in ArQule common stock, *, in an aggregate amount of
                       * dollars ($*).

                 (iii) If ArQule meets the Production Goals as determined by the
                       Steering Committee for the second year of the
                       Collaboration Program to produce * Pfizer Compounds,
                       then, within 30 days of the second anniversary of the
                       Effective Date, Pfizer shall make an additional equity
                       investment in ArQule common stock, *, in an aggregate
                       amount of * dollars ($*).

           c.    * REIMBURSEMENT. Pfizer shall pay, or at ArQule's option,
                 reimburse ArQule for all Collaboration Program costs associated
                 with * exceeding * dollars ($*) per *. ArQule shall not make
                 any reagent purchases in connection with the Collaboration
                 Program in excess of $* without prior approval from the
                 Steering Committee.

     4.5   US FUNDS. Each payment pursuant to this Agreement shall be paid in
           U.S. currency by wire transfer in immediately available funds to an
           account designated by ArQule in writing, or by other mutually
           acceptable means, within thirty (30) days after receipt by Pfizer of
           the invoice from ArQule, unless otherwise specified in this Agreement
           or agreed to by the Parties.

     4.6   RECORDS. ArQule shall keep for three (3) years following the
           conclusion of each year of the Agreement Period, complete and
           accurate records with respect to such year of all expenditures and
           costs of the work performed under this Agreement, and payments
           received by it from Pfizer under Section 4. The records shall conform
           to good accounting principles as applied to a similar company
           similarly situated. Pfizer shall have the right at its own expense
           during the subsequent three-year period to appoint an independent
           certified public accountant reasonably acceptable to ArQule to
           inspect said records to verify the accuracy of such expenditures.
           Upon reasonable notice by Pfizer, ArQule shall make its records
           available for inspection by the independent certified public
           accountant during regular business hours at the place or places where
           such records are customarily kept. This right of inspection shall not
           be exercised more than once in any calendar year. All information
           concerning such expenditures, and all information learned in the
           course of any audit or inspection, shall be deemed to be ArQule
           Confidential Information. The failure of Pfizer to request
           verification of any expenditure within such three-year retention
           period shall be considered acceptance by Pfizer of the accuracy of
           such expenditures, and

<Page>

                                       8

           ArQule shall have no obligation to maintain any records pertaining to
           such report or statement beyond such three-year period. The findings
           of such inspection, if any, shall be binding on the Parties.

5.   TREATMENT OF CONFIDENTIAL INFORMATION

     5.1   CONFIDENTIALITY

           a.    Subject to Section 5.2, each of ArQule and Pfizer agree that
                 during the Agreement Period, and for ten (10) years thereafter,
                 it will keep confidential, and will cause its Affiliates,
                 agents and sublicensees to keep confidential, all Confidential
                 Information of the other Party that is disclosed to it, or to
                 any of its Affiliates, agents or sublicensees by the other
                 Party. Each Party shall take such action, and shall cause its
                 Affiliates and agents and sublicensees to take such action, to
                 preserve the confidentiality of the other's Confidential
                 Information as it would customarily take to preserve the
                 confidentiality of its own Confidential Information. Neither
                 Party nor any of its respective Affiliates, agents or
                 sublicensees shall use the other Party's Confidential
                 Information except in furtherance of the Collaboration Program
                 and as otherwise expressly permitted in this Agreement.

           b.    Pfizer and ArQule each agree to disclose the other's
                 Confidential Information only to those officers, employees or
                 advisers on a need-to-know basis on the same obligations of
                 confidentiality specified hereunder. Pfizer and ArQule each
                 agree not to disclose the other's Confidential Information to
                 any third party contractors who are not advisers under any
                 circumstance without written permission from the other Party.

           c.    For purposes of this Section 5, all Pfizer Compounds and Pfizer
                 Technology shall be deemed to be Pfizer Confidential
                 Information; provided, however that the period of
                 confidentiality and non-use for Pfizer Compounds shall run for
                 twenty (20) years. In furtherance of the foregoing covenant,
                 ArQule shall maintain a database containing the structures and
                 other information regarding Pfizer Compounds, and will restrict
                 access to such database, pursuant to the provisions of this
                 Section 5, so that ArQule will avoid any synthesis of a
                 compound or intermediate that would be the same as any Pfizer
                 Compound identified in such database. If ArQule consults such
                 database and determines that it has produced a Pfizer Compound
                 outside the Collaboration Program, ArQule chemists shall be so
                 informed and instructed to cease work on those Pfizer
                 Compounds. ArQule may request a possible collaboration around
                 such Pfizer Compounds and Pfizer shall consider such request in
                 good faith. If Pfizer notifies ArQule in writing that it
                 declines to collaborate then ArQule shall promptly destroy all
                 quantities of such chemical entity that it has made. Subject to
                 ArQule's confidentiality obligations to any third party, Pfizer
                 shall have the right to monitor and review ArQule activities
                 with respect to Pfizer Compound registration and production
                 restriction during normal business hours and upon reasonable
                 notification, but no more than once in any two consecutive
                 Calendar Quarters. Notwithstanding the provisions of Section
                 5.1(d), upon

<Page>

                                       9

                 expiration of the confidentiality period in this Section
                 5.1(c), ArQule will delete the structures of the Pfizer
                 Compounds and all related information from its database.

           d.    Program Technology shall be deemed to be Pfizer Confidential
                 Information during the Agreement Period.

     5.2   PUBLICATION. Notwithstanding any provision in this Agreement to the
           contrary, results obtained in the course of the Collaboration Program
           may be submitted for publication following scientific review by the
           Steering Committee and subsequent written approval by ArQule and
           Pfizer, which approval shall not be unreasonably withheld,
           conditioned or delayed. After receipt of the proposed publication by
           both Pfizer and ArQule, written approval or disapproval shall be
           provided within thirty (30) days for a manuscript, within fourteen
           (14) days for an abstract for presentation at, or inclusion in, the
           proceedings of a scientific meeting.

     5.3   PUBLICITY. Except as required by law, neither Party may disclose the
           terms of this Agreement nor the work to be performed pursuant to it
           without the written consent of the other Party, which consent shall
           not be unreasonably withheld, conditioned or delayed; provided,
           however, that ArQule may disclose the terms, or provide copies, of
           this Agreement as necessary in the normal course of business to its
           advisers, and to bankers and investors in order to obtain financing.

     5.4   PERMITTED DISCLOSURE.

           a.    DISCLOSURE REQUIRED BY LAW. If either Party is requested to
                 disclose the Confidential Information in connection with a
                 legal or administrative proceeding or is otherwise required by
                 law to disclose the other Party's Confidential Information,
                 such Party will give the other Party prompt notice of such
                 request. The Party to whom such Confidential Information
                 belongs may seek an appropriate protective order or other
                 remedy or waive compliance with the provisions of this
                 Agreement. If such Party seeks a protective order or other
                 remedy, the other Party will cooperate. If such Party fails to
                 obtain a protective order or waive compliance with the relevant
                 provisions of this Agreement, the other Party will disclose
                 only that portion of Confidential Information which its legal
                 counsel determines it is required to disclose.

           b.    DISCLOSURE OF INVENTIONS. Each Party shall promptly inform the
                 other about all inventions that are made in the course of
                 carrying out the Collaboration Program by employees of, or
                 consultants to, either of them solely, or jointly with
                 employees of, or consultants to the other.

           c.    OTHER EXCLUSIONS. Confidential Information shall not include
                 information:

           (i)   which is or becomes generally available to the public other
                 than as a result of disclosure thereof by the receiving Party;

           (ii)  which is received by the receiving Party on a nonconfidential
                 basis from a third party that is not itself under any
                 obligation of confidentiality or

<Page>

                                       10

                 nondisclosure to the disclosing Party or any other person or
                 entity with respect to such information; or

           (iii) which the receiving Party establishes by competent proof was in
                 its possession at the time of disclosure by the disclosing
                 Party and was not acquired, directly or indirectly from the
                 disclosing Party.

6.   INTELLECTUAL PROPERTY RIGHTS.

     6.1   OWNERSHIP. All ArQule Confidential Information and ArQule Technology
           shall be owned solely by ArQule. All Pfizer Confidential Information,
           Pfizer Technology and Pfizer Compounds shall be owned by Pfizer. All
           Program Technology shall be owned by Pfizer.

     6.2   GRANTS OF LICENSES.

           a.    Subject to Section 5, ArQule grants to Pfizer a non-exclusive,
                 worldwide, * license to *, ArQule Confidential Information and
                 ArQule Technology, as Pfizer sees fit in the *. Except as
                 limited by Section 8.4 of this Agreement, such license shall
                 survive the expiration or termination of this Agreement.

           b.    During the Agreement Period, subject to Section 5, Pfizer
                 grants to ArQule a non-exclusive, worldwide, * license to make
                 and use, but not to sell, sublicense or otherwise transfer, *.

           c.    Upon the expiration or termination of this Agreement, subject
                 to Section 5, Pfizer hereby * the expiration or termination of
                 this Agreement.

     6.3   NO FURTHER LICENSES. Except for the rights and licenses expressly
           granted in this Agreement, no further rights or licenses are granted
           in or under this Agreement, either expressly or by implication.

     6.4   Patents:

           a.    Consistent with their respective ownership rights under Section
                 6.1, ArQule shall decide, in its sole discretion, whether to
                 file any patent applications directed to any discovery or
                 invention that constitutes ArQule Technology or ArQule
                 Confidential Information, and Pfizer shall decide, in its sole
                 discretion, whether to file any patent applications directed to
                 any discovery or invention that constitutes Pfizer Technology,
                 Pfizer Confidential Information, Pfizer Compounds, or Program
                 Technology.

           b.    If Pfizer decides to file any patent applications to any
                 discovery and/or invention that constitutes Program Technology,
                 ArQule, shall cooperate with Pfizer and prepare, complete, and
                 provide, within a reasonable period of time after such a
                 request, at Pfizer's expense, and without any further
                 compensation to ArQule by Pfizer, any and all documents
                 requested by Pfizer, for use in preparing, filing, and
                 prosecuting any and all patent applications relating to Program
                 Technology, and defending and enforcing any and all patents
                 issued therefrom, and ArQule, at Pfizer's

<Page>

                                       11

                 expense, and without any further compensation to ArQule, shall
                 execute an assignment of rights to Pfizer with respect to any
                 and all Program Technology. If Pfizer decides, with respect to
                 such a discovery or invention: (a) not to file a patent
                 application, (b) not to file a patent application in a
                 particular country, (c) to abandon a patent application or (d)
                 not to pay a maintenance fee necessary to keep a patent
                 application pending and/or an issued patent in force, Pfizer
                 shall notify ArQule, and ArQule, at ArQule's sole expense, and
                 without any further compensation to ArQule by Pfizer, after
                 notice to and consultation with Pfizer, shall have the right to
                 take any action that Pfizer so declines, including maintenance,
                 defense and enforcement specifically related thereto.

                 If ArQule takes any such action pursuant to this Section 6.4.2,
                 it shall either do so in Pfizer's name, or Pfizer, in its sole
                 discretion and at ArQule's expense, shall execute an assignment
                 of rights to ArQule, as appropriate, and ArQule shall grant to
                 Pfizer a non-exclusive, worldwide, royalty-free, perpetual
                 license to make, use, sell, offer for sale and import any and
                 all discoveries and inventions in any and all of such patent
                 applications or issued patents, as Pfizer sees fit in the
                 discovery, development and commercialization of pharmaceutical
                 products.

7.   ACQUISITION OF RIGHTS FROM THIRD PARTIES. During the Agreement Period,
     ArQule and Pfizer shall each promptly notify the Steering Committee of any
     appropriate opportunities to acquire in any manner from third parties,
     technology or patents or information which it elects to use in the course
     of performing the Collaboration Program. The Steering Committee shall
     decide if such rights should be acquired in connection with the
     Collaboration Program and, if so, whether by ArQule, Pfizer or both, and
     how acquisition costs in connection therewith should be apportioned between
     the Parties, it being understood that nothing herein shall obligate either
     Party to obtain such rights. If acquired, such rights shall become part of
     the Confidential Information, or Technology, of the acquiring Party, or
     Program Technology, as appropriate.

8.   TERM, TERMINATION AND DISENGAGEMENT.

     8.1   TERM. Unless sooner terminated, as provided below or extended, by
           mutual written agreement of the Parties, this Agreement shall expire
           on the seventh (7) year anniversary of the Effective Date.

     8.2   EVENTS OF TERMINATION FOR CAUSE. The following events shall
           constitute events of termination ("Events of Termination") for cause:

           a.    if any representation or warranty by ArQule or Pfizer in
                 Section 9 of this Agreement shall prove to have been incorrect
                 in any material respect when made;

           b.    ArQule or Pfizer shall fail to comply with any representation,
                 warranty or covenant contained in this Agreement or in any of
                 the Exhibits attached to it, and any such failure shall remain
                 unremedied for thirty (30) days after written notice to the
                 failing Party; or

           c.    the event of bankruptcy, insolvency or dissolution of either
                 Party;

<Page>

                                       12

                 Upon an Event of Termination the Party not responsible may, by
                 written notice to the other Party, immediately terminate this
                 Agreement, provided, however, that in the event of termination
                 pursuant to (a) above, the terminating Party shall provide the
                 other Party with thirty (30) days advance written notice.

     8.3   TERMINATION BY PFIZER.

           a.    Notwithstanding any rights granted under this Section 8, Pfizer
                 shall have the right to terminate this Agreement, without
                 cause, anytime on or after four years following the Effective
                 Date upon six (6) months prior written notice and payment as
                 set forth in the immediately following sentence to ArQule. If
                 Pfizer terminates this Agreement pursuant to this Section
                 8.3(a), Pfizer will pay to ArQule contemporaneously with
                 delivery of such notice * for the * following such notice. The
                 Steering Committee will determine a new Project Plan for such
                 *.

           b.    NOTICE REGARDING CHANGE OF CONTROL. During the Agreement
                 Period, ArQule shall provide Pfizer, under confidentiality,
                 notice of any sale, merger, acquisition, or transfer of all or
                 substantially all of the assets of ArQule with or to a third
                 party ("Transaction") upon not less than 4 months prior notice
                 which notice shall include the identity of such third party and
                 reference to this Section 8.3(b). Pfizer shall have the right
                 to terminate this Agreement effective upon consummation of the
                 Transaction with written notice to ArQule within ninety (90)
                 days following receipt of ArQule's notice of Transaction. In
                 the event Pfizer fails to provide written notice of termination
                 to ArQule within such ninety (90) day time period, or indicates
                 in such response that it would waive such termination rights,
                 Pfizer shall be deemed to have irrevocably waived such
                 termination rights with respect to such Transaction for
                 purposes of Section 8.3(b).

     8.4   EFFECT OF TERMINATION. Termination of this Agreement for any reason
           shall be without prejudice to:

           a.    the rights and obligations of the Parties provided in Sections
                 5, 6.2(a) and (c), 6.4, 8.5 and 11 and any other Sections which
                 provide by its terms performance by either Party subsequent to
                 termination.

           b.    ArQule's right to receive all payments accrued up to the date
                 of termination under Section 4; or

           c.    any other remedies which either Party may otherwise have.

           d.    In the event ArQule terminates this Agreement pursuant to
                 Section 8.2, Pfizer shall have the right to * by *, within 30
                 days of receipt of termination notice by ArQule. If Pfizer
                 fails to * shall automatically terminate.

     8.5   TRANSFER OF RIGHTS. Upon expiration or termination of this Agreement,
           Pfizer shall transfer to ArQule all of Pfizer's rights, title and
           interest in and to the hardware associated with the AMAP System, for
           due consideration of * ($*).

<Page>

                                       13

9.   REPRESENTATIONS AND WARRANTIES. Each of ArQule and Pfizer represents and
     warrants to the other as follows:

           a.    It is a corporation duly organized, validly existing and is in
                 good standing under the laws of its jurisdiction of
                 incorporation or formation, is qualified to do business and is
                 in good standing as a foreign corporation in each jurisdiction
                 in which the conduct of its business or the ownership of its
                 properties requires such qualification; and it has all
                 requisite power and authority, corporate or otherwise, to
                 conduct its business as now being conducted, to own, lease and
                 operate its properties and to execute, deliver and perform this
                 Agreement.

           b.    The execution, delivery and performance by it of this Agreement
                 have been duly authorized by all necessary corporate action and
                 do not and will not (a) require any consent or approval of its
                 stockholders beyond the approvals already obtained, (b) violate
                 any provision of any law, rule, regulations, order, writ,
                 judgment, injunction, decree, determination or award presently
                 in effect having applicability to it or any provision of its
                 certificate of incorporation or by-laws or (c) result in a
                 breach of or constitute a default under any material agreement,
                 mortgage, lease, license, permit or other instrument or
                 obligation to which it is a Party or by which it or its
                 properties may be bound or affected.

           c.    This Agreement is a legal, valid and binding obligation of it
                 enforceable against it in accordance with its terms and
                 conditions, except as such enforceability may be limited by
                 applicable bankruptcy, insolvency, moratorium, reorganization
                 or similar laws, from time to time in effect, affecting
                 creditor's rights generally.

           d.    It is not under any obligation to any person, or entity,
                 contractual or otherwise, that is conflicting or inconsistent
                 in any respect with the terms of this Agreement or that would
                 impede the diligent and complete fulfillment of its
                 obligations.

           e.    It has good and marketable title to or valid leases or licenses
                 for, all of its properties, rights and assets necessary for the
                 fulfillment of its responsibilities under the Collaboration
                 Program, subject to no claim of any third party other than any
                 relevant lessors or licensors.

10.  ADDITIONAL COVENANTS. Throughout the Agreement Period, each of ArQule and
     Pfizer each shall:

           a.    maintain and preserve its corporate existence, rights,
                 franchises and privileges in the jurisdiction of its
                 incorporation or formation, and qualify and remain qualified as
                 a foreign corporation in good standing in each jurisdiction in
                 which such qualification is from time to time necessary or
                 desirable in view of its business and operations or the
                 ownership of its properties.

           b.    comply in all material respects with the requirements of all
                 applicable laws, rules, regulations and orders of any
                 government authority to the

<Page>

                                       14

                 extent necessary to conduct the Collaboration Program, except
                 for those laws, rules, regulations, and orders it may be
                 contesting in good faith.

           c.    Concurrently with the execution of this Agreement, ArQule and
                 Pfizer shall enter into the Equity Purchase Agreement of even
                 date herewith appended to and made part of this Agreement as
                 Exhibit G.

11.  INDEMNIFICATION. Pfizer and ArQule will indemnify, defend and hold each
     other harmless for any and all damages, settlements, costs, legal fees and
     other expenses incurred in connection with a claim by a third party against
     either Party based on any action or omission of the indemnifying Party's
     agents, employees, or officers related to its obligations under this
     Agreement; provided, however, that the foregoing shall not apply (i) to the
     extent the claim is found to be based upon the negligence, recklessness or
     willful misconduct of the Party seeking indemnification; or (ii) if such
     Party fails to give the other Party prompt notice of any claim it receives
     and such failure materially prejudices the other Party with respect to any
     claim or action to which its obligation pursuant to this Section applies.
     In addition, Pfizer will indemnify, defend and hold ArQule harmless for any
     and all damages, settlements, costs, legal fees and other expenses incurred
     in connection with a claim by a third party against ArQule based on any
     action or omission of Pfizer's agents, employees, or officers related to
     sale of pharmaceutical products by Pfizer and the activities required in
     connection therewith, including but not limited to the manufacture,
     production, testing, labeling, use, shipment, storage, sale and delivery of
     such products by or on behalf of Pfizer; provided, however, that the
     foregoing shall not apply (i) to the extent the claim is found to be based
     upon the negligence, recklessness or willful misconduct of ArQule; or (ii)
     if ArQule fails to give Pfizer prompt notice of any claim it receives and
     such failure materially prejudices Pfizer with respect to any claim or
     action to which its obligation pursuant to this Section applies. If one
     Party is obligated to indemnify the other Party, then it shall in its sole
     discretion, choose legal counsel, control the defense of such claim or
     action and settle the same on such terms and conditions it deems advisable,
     except that it may not settle a claim or action under this Section 11
     without the consent of the other Party if such settlement would impose any
     monetary obligations on the other Party that would not be subject to
     indemnification by the other Party or require the other Party to submit to
     an injunction or otherwise limit the actions of its Affiliates, employees,
     agents, officers or directors.

12.  NOTICES. All notices shall be in writing mailed via certified mail, return
     receipt requested, courier, or facsimile transmission addressed as follow,
     or to such other address as may be designated from time to time:

     If to Pfizer:            Pfizer Global Research and Development
                              50 Pequot Avenue
                              New London, CT 06320
                              Attn: Vice President of Strategic Alliances
                              Copy to: Assistant General Counsel PGRD

     If to ArQule:            ArQule Inc.
                              19 Presidential Way
                              Woburn, MA
                              Attn: President and Chief Executive Officer

<Page>

                                       15

                              Copy to: General Counsel

   Notices shall be deemed given as of the date received at the above-specified
   address.

13.  DISPUTE RESOLUTION. In the event of any dispute, disagreement or other
     claim between the Parties arising out of or relating to this Agreement
     ("Dispute"), the Steering Committee shall first attempt to resolve such
     dispute amicably. In the event the Steering Committee cannot resolve such
     dispute within two (2) weeks after referral of the Dispute to the Steering
     Committee, at the option of either Party, the Dispute shall be referred to
     a senior executive officer of each Party. In the event such senior
     executive officers cannot resolve such Dispute within two (2) weeks after
     the referral of the Dispute to such officers, each Party shall be entitled
     to seek all remedies available at law or in equity. Notwithstanding the
     foregoing, each Party shall be entitled to seek injunctive relief and other
     provisional remedies at any time.

14.  GOVERNING LAW. This Agreement shall be governed by and construed in
     accordance with the laws of the State of New York, without regard to its
     conflict of laws principles.

15.  MISCELLANEOUS.

     15.1  BINDING EFFECT. This Agreement shall be binding upon and inure to the
           benefit of the Parties and their respective legal representatives,
           successors and permitted assigns.

     15.2  HEADINGS. Paragraph headings are inserted for convenience of
           reference only and do not form a part of this Agreement.

     15.3  COUNTERPARTS. This Agreement may be executed simultaneously in two or
           more counterparts, each of which shall be deemed an original.
           Signatures may be transmitted via facsimile, thereby constituting the
           valid signature and delivery of this Agreement.

     15.4  AMENDMENT, WAIVER. This Agreement may be amended, modified,
           superseded or cancelled, and any of the terms may be waived, only by
           a written instrument executed by each Party or, in the case of
           waiver, by the Party or Parties waiving compliance. The delay or
           failure of any Party at any time or times to require performance of
           any provisions shall in no manner affect the rights at a later time
           to enforce the same. No waiver by any Party of any condition or of
           the breach of any term contained in this Agreement, whether by
           conduct, or otherwise, in any one or more instances, shall be deemed
           to be, or considered as, a further or continuing waiver of any such
           condition or of the breach of such term or any other term of this
           Agreement.

     15.5  NO THIRD PARTY BENEFICIARIES. No third party including any employee
           of any Party to this Agreement, shall have or acquire any rights by
           reason of this Agreement. Nothing contained in this Agreement shall
           be deemed to constitute the Parties as partners with each other or
           any third party, or in a joint venture relationship.

     15.6  ENTIRE AGREEMENT. This Agreement and the Stock Purchase Agreement
           attached hereto as Exhibit G constitute the entire agreement between
           the Parties with respect to the subject matter hereof and supersede
           all other agreements and

<Page>

                                       16

           understandings, including without limitation to the 1999 Agreement,
           between the Parties with respect to same.

     15.7  ASSIGNMENT AND SUCCESSORS. Subject to the terms and conditions of
           Section 8.3(b), this Agreement may not be assigned by either Party
           without the prior written consent of the other Party, except that
           each Party may assign this Agreement and the rights and interests of
           such Party, in whole or in part, to any of its Affiliates, any
           purchaser of all or substantially all of its assets or to any
           successor corporation resulting from any merger or consolidation of
           such party with or into such corporations.

     15.8  FORCE MAJEURE. Neither Pfizer nor ArQule shall be liable for failure
           of or delay in performing obligations set forth in this Agreement,
           and neither shall be deemed in breach of its obligations, if such
           failure or delay is due to natural disasters or any causes reasonably
           beyond the control of Pfizer or ArQule.

     15.9  SEVERABILITY. If any provision of this Agreement is or becomes
           invalid or is ruled invalid by any court of competent jurisdiction or
           is deemed unenforceable, it is the intention of the Parties that the
           remainder of the Agreement shall not be affected so long as the
           essential benefits of this Agreement remain enforceable and
           obtainable.

<Page>

                                       17

IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed by
their duly authorized representatives.

PFIZER INC                                   ARQULE INC.

By:                                          By:
     --------------------------                    --------------------------

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

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

Date:                                        Date:
     --------------------------                    --------------------------

cc:      Pfizer Inc, Legal Division, New London, CT 06320

<Page>

                               SUMMARY OF EXHIBITS

EXHIBITS:

A:   AMAP SYSTEM DESCRIPTION

B:   INFORMATICS/LIBRARY DESIGN TOOLS

C:   PROJECT PLAN

D:   CERTIFICATE OF OWNERSHIP

E:   SUCCESS PAYMENT

F:   PAYMENT SCHEDULE

G:   EQUITY AGREEMENT

<Page>

                                    EXHIBIT A

AMAP DESCRIPTION

*

<Page>

                                    EXHIBIT B

Informatics/Library Design Tools

*

<Page>

                                  CONFIDENTIAL

                                    EXHIBIT C

                           PFIZER/ArQULE COLLABORATION

                                  PROJECT PLAN

                                DECEMBER 18, 2001

                     ERIC ROSKAMP AND PAUL McGUIRK - PFIZER

                     JIM KYRANOS AND CARMEN BALDINO - ArQULE

<Page>

                                  CONFIDENTIAL

                                TABLE OF CONTENTS

1.0  EXECUTIVE SUMMARY

2.0  INTRODUCTION

3.0  COLLABORATION PLAN

     *

     TABLE 1

4.0  FIRST YEAR OF INCREASED COLLABORATION - 2002

     *

5.0  SECOND YEAR OF INCREASED COLLABORATION - 2003

     *

6.0  THIRD YEAR OF INCREASED COLLABORATION - 2004

     *

7.0  FOURTH, FIFTH AND SIXTH YEAR OF INCREASED COLLABORATION - 2005-2007

     *

8.0  SEVENTH YEAR OF INCREASED COLLABORATION - 2008

9.0  COLLABORATION MANAGEMENT AND STAFFING

     9.1 STEERING COMMITTEE

     9.2 STAFFING

     9.3 LIBRARY PLANNING AND MANAGEMENT

     9.4 KEY PERSONNEL

     9.5 OPERATIONS

10.0 PFIZER EXCLUSIVITY

     *

<Page>

11.0 GLOSSARY

*

<Page>

                                    EXHIBIT D

<Page>

                            CERTIFICATE OF OWNERSHIP

This Certificate of Ownership is issued in connection with that certain
Technology Acquisition Agreement, dated as of July 19, 1999 (the "Agreement") by
and between Pfizer, Inc. and its Affiliates (collectively, "Pfizer") and ArQule,
Inc. ("ArQule"). Capitalized terms used herein without definition shall have the
same respective meanings as those ascribed to them in the Agreement

1.   I, James Kyranos, the undersigned, being a duly elected and qualified Vice
President of ArQule, on behalf of ArQule do hereby certify that:

           (a) On January 3, 2000, ArQule completed configuration, delivery and
           installation in the Production Facility of a new, operational System
           conforming to the description set forth in Exhibit B to the Agreement
           and containing the equipment (the "System Equipment") listed in
           Exhibit C to the Agreement (copies of which exhibits are annexed
           hereto);

           (b) The Steering Committee has determined that the Move-In Date was
           January 3, 2000; and

           (c) Pursuant to Section 3.1 of the Agreement, Pfizer, effective as of
           January 3, 2000, acquired legal title to the System Equipment and
           assumed the risk of loss thereof.

2.   As a further assurance to Pfizer, ArQule hereby represents, warrants and
     confirms that, pursuant to the terms of the Agreement

           (a) the System Equipment was, on January 3, 2000, free and clear of
           all encumbrances and ArQule had the right to transfer and convey the
           same,

           (b) ArQule transferred and conveyed to Pfizer all of its rights and
           interests in and to the System Equipment; and

           (c) The processes, methods and other ArQule Technology which, in
           addition to the System Equipment, are elements of the System have
           been licensed to Pfizer.

By acceptance of this Certificate of Ownership, Pfizer acknowledges that the
statements contained in paragraphs 1(a), (b) and (c) above are true, complete
and accurate in all respects.

IN WITNESS WHEREOF, I have hereunto set my hand and the corporate seal of ArQule
to this Certificate of Ownership as of May 31, 2000.

<Page>

     [SEAL]                        ARQULE, INC.

                                   James Kyranos, Vice President

     I, Michael D. Rivard, Vice President and Assistant Secretary of ArQule, do
hereby certify that James Kyranos is a duly elected and qualified Vice President
of ArQule, and that his signature set forth above is his true signature.

     IN WITNESS WHEREOF, I have hereunto set my hand as of May 31, 2000

                                   Michael D. Rivard, Vice President
                                   and Assistant Secretary

<Page>

                                    EXHIBIT E

                            Success Payment Schedule

<Table>
<Caption>
     ------------------------------------------------------------
             YEAR           2002           2003         2004
     ------------------------------------------------------------
        <S>                   <C>            <C>          <C>

        Quarter 1 ($*)        *              *            *
     ------------------------------------------------------------

        Quarter 2 ($*)        *              *            *
     ------------------------------------------------------------

        Quarter 3 ($*)        *              *            *
     ------------------------------------------------------------

        Quarter 4 ($*)        *              *            *
     ------------------------------------------------------------
           TOTAL              *              *            *
     ------------------------------------------------------------
</Table>

<Page>

                                    EXHIBIT F

                                PAYMENT SCHEDULE
<Table>
<Caption>
     ----------------------------------------------------------------------
     Year                  2002  2003  2004  2005  2006  2007  2008   Total
     ----------------------------------------------------------------------
     <S>                   <C>   <C>   <C>   <C>   <C>   <C>   <C>    <C>
     # of Compounds/
     year (000's)          *     *     *     *     *     *     *      *
     ----------------------------------------------------------------------
     $ / compound          *     *     *     *     *     *     *      *
     ----------------------------------------------------------------------

     ----------------------------------------------------------------------
     Total $/year ($ *)    *     *     *     *     *     *     *      *
     ----------------------------------------------------------------------
     Technology Cost ($ *) *     *     *     *     *     *     *      *
     ----------------------------------------------------------------------
     Lease Payments ($ *)  *     *                                    *
     ----------------------------------------------------------------------

     ----------------------------------------------------------------------
     Compound Cost ($ *)   *     *     *     *     *     *     *      *
     ----------------------------------------------------------------------

     ----------------------------------------------------------------------
</Table>

<Page>

                                    EXHIBIT G

<Page>

                         COMMON STOCK PURCHASE AGREEMENT

                                     between

                                  ARQULE, INC.

                                       and

                                 PFIZER HOLDINGS
                                     EUROPE

                          dated as of December 19, 2001

<Page>

                                TABLE OF CONTENTS

<Table>
<Caption>
                                                                                             Page
<S>             <C>                                                                             <C>
SECTION 1.      AUTHORIZATION OF SALE OF THE SHARES.............................................1

SECTION 2.      AGGREGATE PURCHASE PRICE........................................................1

SECTION 3.      DELIVERY OF THE SHARES AT THE CLOSING...........................................1

SECTION 4.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF ARQULE.............................1
     4.1        ORGANIZATION AND QUALIFICATION..................................................1
     4.2        AUTHORIZED CAPITAL STOCK........................................................2
     4.3        CONSENTS; DUE EXECUTION; DELIVERY AND PERFORMANCE OF THE AGREEMENT..............2
     4.4        ISSUANCE, SALE AND DELIVERY OF THE SHARES.......................................2
     4.5        EXEMPT TRANSACTION..............................................................2
     4.6        COMPLIANCE WITH RULE 144........................................................2
     4.7        DISCLOSURE......................................................................2
     4.8        ADDITIONAL INFORMATION..........................................................3
     4.9        NO MATERIAL CHANGES.............................................................3
     4.10       LITIGATION......................................................................3
     4.11       VOTING ARRANGEMENTS.............................................................3
     4.12       NASDAQ NATIONAL MARKET DESIGNATION..............................................3

SECTION 5.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF PFIZER.............................3
     5.1        INVESTMENT CONSIDERATIONS.......................................................3
     5.2        DUE EXECUTION, DELIVERY AND PERFORMANCE OF THE AGREEMENT........................4

SECTION 6.      CONDITIONS TO THE OBLIGATIONS OF THE PURCHASER..................................4
     6.1        ACCURACY OF REPRESENTATIONS AND WARRANTIES......................................5
     6.2        PERFORMANCE.....................................................................5
     6.3        OPINION OF COUNSEL..............................................................5
     6.4        CERTIFICATES AND DOCUMENTS......................................................5
     6.5        OTHER MATTERS...................................................................5

SECTION 7.      CONDITIONS TO THE OBLIGATIONS OF ARQULE.........................................5
     7.1        ACCURACY OF REPRESENTATIONS AND WARRANTIES......................................5
     7.2        CERTIFICATES AND DOCUMENTS......................................................5
     7.3        PERFORMANCE.....................................................................6
     7.4        OTHER MATTERS...................................................................6
</Table>

                                       i

<Page>

<Table>
<S>             <C>                                                                            <C>
SECTION 8.      SURVIVAL OF REPRESENTATIONS, WARRANTIES AND AGREEMENTS;
                  ASSIGNABILITY OF RIGHTS.......................................................6

SECTION 9.      INCIDENTAL REGISTRATION.........................................................6
     9.1        REGISTRATION OF SHARES..........................................................6
     9.2        ALLOCATION OF EXPENSES..........................................................7
     9.3        CESSATION OF SALES..............................................................7
     9.4        INDEMNIFICATION.................................................................7
     9.5        TERMINATION.....................................................................9

SECTION 10.     COVENANTS OF PFIZER AND ARQULE..................................................9
     10.1         STANDSTILL AGREEMENT..........................................................9
                 (a)    CERTAIN DEFINITIONS.....................................................9
                 (b)    PROHIBITED ACQUISITIONS................................................10
                 (c)    EXCEPTIONS.............................................................11
                 (d)    PROHIBITED TRANSFER....................................................11
                 (e)    AFFILIATES OF PFIZER...................................................11
     10.2       INFORMATION BY HOLDER..........................................................11
     10.3       "STAND-OFF" AGREEMENT..........................................................11
     10.4       TERM...........................................................................11

SECTION 11.     MISCELLANEOUS..................................................................11
     11.1        NOTICES.......................................................................12
     11.2        ENTIRE AGREEMENT..............................................................12
     11.3        ASSIGNMENT....................................................................12
     11.4        AMENDMENTS AND WAIVERS........................................................12
     11.5        HEADINGS......................................................................13
     11.6        SEVERABILITY..................................................................13
     11.7        GOVERNING LAW.................................................................13
     11.8        COUNTERPARTS..................................................................13
     11.9        EXPENSES......................................................................13
     11.10       PUBLICITY.....................................................................13

SECTION 12.     DEFINITIONS....................................................................13
</Table>

                                       ii

<Page>

                         COMMON STOCK PURCHASE AGREEMENT

     THIS COMMON STOCK PURCHASE AGREEMENT dated as of December 19, 2001 (the
"Agreement") is made between ARQULE, INC., a corporation organized under the
laws of the State of Delaware ("ArQule" or the "Company"), and PFIZER HOLDINGS
EUROPE ("Pfizer"), an unlimited liability company incorporated under the laws of
the Republic of Ireland.

                                  R E C I T A L

     ArQule desires to sell to Pfizer, and Pfizer desires to purchase from
ArQule, pursuant to this Agreement, shares of ArQule's common stock, with an
aggregate purchase price of $10,000,000, on the terms and conditions described
herein and in reliance upon the representations, warranties and agreements
contained herein.

     ArQule and Pfizer have agreed, in the Collaboration Agreement dated as of
December 19, 2001 ("Collaboration Agreement"), that Pfizer shall purchase, over
the next two years, up to an additional $8,000,000 of ArQule's common stock if
ArQule meets certain performance requirements specified in the Collaboration
Agreement, on the terms and conditions set forth in the Collaboration Agreement.

     Defined terms are set forth in Section 12.

     NOW THEREFORE, in consideration of the premises and of the covenants herein
contained, the parties hereto mutually agree as follows:

     SECTION 1.      AUTHORIZATION OF SALE OF THE SHARES. Subject to the terms
and conditions of this Agreement, ArQule has authorized the sale to Pfizer of *
shares of the common stock, par value $0.01 per share (the "Common Stock"), of
ArQule at a price of $* per share, at an aggregate purchase price of
$10,000,000. Collectively, the shares of Common Stock which shall be purchased
pursuant to this Section I are referred to herein as the "Shares."

     SECTION 2.      AGGREGATE PURCHASE PRICE.. The aggregate purchase price
for the Shares (the "Aggregate Purchase Price") shall be $10,000,000.

     SECTION 3.      DELIVERY OF THE SHARES AT THE CLOSING. The closing of the
purchase and sale of the Shares (the "Closing") shall occur on or before
December 28, 2001 at 10:00 a.m. at the offices of ArQule, 19 Presidential Way,
Woburn, Massachusetts, or at such other time and date and at such other place as
may be agreed upon by ArQule and Pfizer (the "Closing Date"). Subject to the
terms and conditions of this Agreement, at the Closing, Pfizer shall pay to
ArQule an amount in cash or by wire transfer equal to the Aggregate Purchase
Price and ArQule shall deliver to Pfizer one or more stock certificates in such
denomination and registered in the name of Pfizer, or in such nominee name(s) as
designated by Pfizer, representing the number of Shares being purchased.

     SECTION 4.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF ARQULE.
ArQule hereby represents and warrants to, and covenants with, Pfizer as follows:

           4.1       ORGANIZATION AND QUALIFICATION. ArQule is a corporation
duly organized, validly existing and in good standing under the laws of the
State of Delaware and has all requisite corporate power and authority to conduct
its business as currently conducted and proposed to be conducted. ArQule is duly
qualified to transact business and to own and use its property and is in good
standing in each jurisdiction in which the failure to so qualify would
reasonably be expected to have a material adverse effect on the business,
operations, properties, assets, prospects or conditions (financial or otherwise)
of ArQule (a "Material Adverse Effect"). Except for Camitro Corporation and
ArQule International, Inc., ArQule has no subsidiaries. Each listed subsidiary
is a corporation duly organized, validly existing and in good standing under the
laws of the State of California and Barbados,

<Page>

respectively, and each has all requisite corporate power and authority to
conduct its business and own and use its property as currently conducted and
proposed to be conducted. Each listed subsidiary is duly qualified to transact
business and to own and use its property and is in good standing in each
jurisdiction in which the failure to so qualify would reasonably be expected to
have a Material Adverse Effect.

           4.2       AUTHORIZED CAPITAL STOCK. ArQule is authorized to issue
50,000,000 shares of Common Stock, and 1,000,000 shares of undesignated
preferred stock, $0.01 par value per share (the "Preferred Stock"). As of
November 15, 2001, there were 20,389,588 shares of Common Stock and no shares of
Preferred Stock outstanding. No shares of capital stock, or securities
convertible into or exercisable for capital stock or other rights affecting the
capital stock, have been issued since such date except for issuances pursuant to
ArQule's equity compensation plans or pursuant to outstanding options, warrants
or rights, in each case as described in filings made with the Securities and
Exchange Commission ("SEC"). All outstanding shares of Common Stock have been
duly authorized and validly issued and are fully paid and non-assessable; and
none of the outstanding shares of Common Stock were issued in violation of the
preemptive rights, if any, of any stockholders of ArQule.

           4.3       CONSENTS; DUE EXECUTION; DELIVERY AND PERFORMANCE OF THE
AGREEMENT. ArQule has all corporate power and authority to execute, deliver and
perform its obligations under this agreement and to issue the Shares. ArQule's
execution, delivery and performance of this Agreement (a) has been duly
authorized under Delaware law by all requisite corporate action by ArQule, (b)
will not violate any applicable law, ordinance, rule or regulation or the
Amended and Restated Certificate of Incorporation or Amended and Restated
By-laws of ArQule or the charter documents of any other corporation of which
ArQule owns at least 50% of the outstanding voting stock (an "ArQule
Subsidiary") or any provision of any indenture, mortgage, agreement, contract or
other material instrument to which ArQule or any ArQule Subsidiary is a party or
by which any of their respective properties or assets is bound as of the date
hereof, and (c) will not require any consent by any person under, constitute or
result (upon notice or lapse of time or both) in a breach of any term, condition
or provision of, or constitute a default or give rise to any right of
termination or acceleration under any such indenture, mortgage, agreement,
contract or other material instrument or result in the creation or imposition of
any lien, security interest, mortgage, pledge, charge or other encumbrance upon
any properties or assets of ArQule or any ArQule Subsidiary. Upon its execution
and delivery, and assuming the valid execution thereof by Pfizer, the Agreement
will constitute a valid and binding obligation of ArQule, enforceable against
ArQule in accordance with its terms, except as enforceability may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws
affecting creditors' and contracting parties' rights generally and except as
enforceability may be subject to general principles of equity (regardless of
whether such enforceability is considered in a proceeding in equity or at law).

           4.4       ISSUANCE, SALE AND DELIVERY OF THE SHARES. When issued and
paid for, the Shares to be sold hereunder by ArQule will be validly issued and
outstanding, fully paid and non-assessable.

           4.5       EXEMPT TRANSACTION. Subject to the accuracy of Pfizer's
representations in Section 5.1 of this Agreement, the issuance of the Shares
will constitute a transaction exempt from the registration requirements of
Section 5 of the Securities Act of 1933, as amended (the "Securities Act") in
reliance upon Section 4(2) of the Securities Act and the regulations promulgated
pursuant thereto.

           4.6       COMPLIANCE WITH RULE 144. At the written request of Pfizer
in connection with any sales of Shares by Pfizer, ArQule shall furnish to
Pfizer, within three days after receipt of such request, a written statement
confirming or denying ArQule's compliance with the filing requirements of the
SEC set forth in SEC Rule 144 as amended from time to time.

           4.7       DISCLOSURE. Neither this Agreement, nor any other items
prepared or supplied to Pfizer by or on behalf of ArQule with respect to the
transactions contemplated hereby contain any untrue statement of a material fact
or omit a material fact necessary to make each statement contained herein or
therein not misleading. There is no fact which ArQule has not disclosed to
Pfizer in writing and of which any of its directors or executive

                                       2
<Page>

officers is aware or should be aware (other than general economic conditions)
which has had or would reasonably be expected to have a Material Adverse Effect
upon the business prospects of ArQule. ArQule further warrants that the annual
report for the year ending December 31, 2001 on Form 10-K did not contain any
untrue statement of a material fact and did not omit to state any material fact
necessary to make the statements therein not misleading as of the date filed.

           4.8       ADDITIONAL INFORMATION. All reports filed by ArQule with
the SEC pursuant to the reporting requirements of the Securities Exchange Act of
1934, as amended (the "Exchange Act"), when filed, did not contain any untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary to make the statements therein, in light of the
circumstances in which they were made, not misleading. ArQule has made all
filings with the SEC which it is required to make, and ArQule has not received
any request from the SEC to file any amendment or supplement to any such
reports. ArQule agrees that, as long as the Collaboration Agreement is in
effect, it will furnish to Pfizer all annual and quarterly reports generally
furnished to ArQule's stockholders in the normal course, and SEC filings upon
request.

           4.9       NO MATERIAL CHANGES. As of the date hereof, there has been
no material adverse change in the business, operations, properties, assets,
prospects or condition (financial or otherwise) of ArQule since the filing date
of ArQule's last report with the Securities and Exchange Commission pursuant to
the reporting requirements of the Exchange Act.

           4.10      LITIGATION. There is no action, suit, investigation or
proceeding pending, or, to ArQule's knowledge, threatened, against ArQule and/or
any ArQule Subsidiary(a) which questions the validity of this Agreement or the
ability of ArQule to consummate the transactions contemplated hereby or (b)
which, singly or in the aggregate, if the subject of unfavorable decision,
ruling or finding, would reasonably be expected to have a Material Adverse
Effect.

           4.11      VOTING ARRANGEMENTS. To the best of ArQule's knowledge
after due inquiry, there are no outstanding stockholder agreements, voting
trusts, proxies or other arrangements or understandings among the stockholders
of ArQule relating to the voting of their respective shares.

           4.12      NASDAQ NATIONAL MARKET DESIGNATION. The Common Stock of
ArQule is listed on the Nasdaq National Market and ArQule knows of no reason or
set of facts which is likely to result in the delisting of the Common Stock on
the Nasdaq National Market System or the inability of such stock to continue to
be included in the Nasdaq National Market.

     SECTION 5.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF PFIZER.

           5.1       INVESTMENT CONSIDERATIONS. Pfizer represents and warrants
to, and covenants with, ArQule that:

                     (a)  Pfizer is knowledgeable, sophisticated and experienced
in making, and is qualified to make, decisions with respect to investments in
shares presenting an investment decision like that involved in the purchase of
the Shares, including investments in securities issued by companies comparable
to ArQule, and has requested, received, reviewed and considered all information
it deems relevant in making an informed decision to purchase the Shares;

                     (b)  Pfizer is acquiring the Shares in the ordinary course
of its business and for its own account for investment only and with no present
intention of distributing any of such Shares or any arrangement or understanding
with any other persons regarding the distribution of such Shares;

                                       3
<Page>

                     (c)  Pfizer understands that the Shares are "restricted
securities" under the federal securities laws inasmuch as they are being
acquired from ArQule in a transaction not involving a public offering and that
under such laws and applicable regulations such securities may be resold without
registration under the Securities Act only in certain limited circumstances. In
this connection Pfizer represents that it is familiar with SEC Rule 144, as
presently in effect, and understands the resale limitations imposed thereby and
by the Securities Act;

                     (d)  Pfizer will not, directly or indirectly, offer, sell,
pledge, transfer or otherwise dispose of (or solicit any offers to buy, purchase
or otherwise acquire or take a pledge of) any of the Shares except in compliance
with the Securities Act, and the rules and regulations promulgated thereunder;

                     (e)  Pfizer qualifies as an "accredited investor" within
the meaning of Rule 501(a)(3) of Regulation D promulgated under the Securities
Act; and

                     (f)  It is understood that the certificates evidencing the
Shares shall bear the following legend unless and until the resale of the Shares
pursuant to an effective Registration Statement (as defined below) or until the
Shares may be sold under Rule 144 without restrictions:

           THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
           1933. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED
           IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO
           THE SECURITIES UNDER SUCH ACT OR, IF REQUESTED BY ARQULE, AN OPINION
           OF COUNSEL REASONABLY SATISFACTORY TO ARQULE AND ITS COUNSEL, THAT
           SUCH REGISTRATION IS NOT REQUIRED UNDER SUCH ACT.

           5.2       DUE EXECUTION, DELIVERY AND PERFORMANCE OF THE AGREEMENT.
Pfizer further represents and warrants to, and covenants with, ArQule that (a)
Pfizer is a corporation duly organized, validly existing and in good standing
under the laws of the State of Delaware and has full right, power, authority and
capacity to enter into this Agreement and to consummate the transactions
contemplated hereby and has taken all necessary action to authorize the
execution, delivery and performance of this Agreement, (b) the execution,
delivery and performance of this Agreement will not violate the charter
documents of Pfizer or any other corporation of which Pfizer owns at least 50%
of the outstanding voting stock (a "Pfizer Subsidiary") or any applicable law,
ordinance, rule or regulation or any provision of any indenture, mortgage,
agreement, contract or other material instrument to which Pfizer or any Pfizer
Subsidiary is a party or by which Pfizer, any Pfizer Subsidiary, or any of their
respective properties or assets is bound as of the date hereof, or result in a
breach of or constitute (upon notice or lapse of time or both) a default under
any such indenture, mortgage, agreement, contract or other material instrument
or result in the creation or imposition of any material lien, security interest,
mortgage, pledge, charge or encumbrance upon any assets of Pfizer or any Pfizer
Subsidiary, and (c) upon the execution and delivery of this Agreement, and
assuming the valid execution thereof by ArQule, this Agreement shall constitute
a valid and binding obligation of Pfizer enforceable in accordance with its
terms, except as enforceability may be limited by applicable bankruptcy,
insolvency, reorganization, moratorium or similar laws affecting creditors' and
contracting parties' rights generally and except as enforceability may be
subject to general principles of equity (regardless of whether such
enforceability is considered in a proceeding in equity or at law).

     SECTION 6.      CONDITIONS TO THE OBLIGATIONS OF THE PURCHASER.

           The obligation of Pfizer to purchase the Shares at the Closing
is subject to the fulfillment, or the waiver in writing by Pfizer, of the
conditions set forth in this Section 6 on or before the Closing Date.

                                      4
<Page>

           6.1       ACCURACY OF REPRESENTATIONS AND WARRANTIES. Each
representation and warranty of ArQule contained in this Agreement shall be true
on and as of the Closing Date with the same effect as though such representation
and warranty had been made on and as of that date.

           6.2       PERFORMANCE. ArQule shall have performed and complied with
all agreements and conditions contained in this Agreement required to be
performed or complied with by ArQule prior to or at the Closing.

           6.3       OPINION OF COUNSEL. Pfizer shall have received an opinion
from Arnold & Porter (or other outside counsel chosen by ArQule and reasonably
acceptable to Pfizer), counsel to ArQule dated as of the Closing Date, addressed
to Pfizer, and substantially in the form attached hereto as EXHIBIT A.

           6.4       CERTIFICATES AND DOCUMENTS. ArQule shall have delivered to
counsel to Pfizer:

                     (a)  a certificate of the Secretary or Assistant Secretary
of ArQule dated as of the Closing Date, certifying as to (i) the incumbency of
officers of ArQule executing this Agreement and all other documents executed and
delivered in connection herewith, (ii) a copy of the By-Laws of ArQule, as in
effect on and as of the Closing Date, and (iii) a copy of the resolutions of the
Board of Directors of ArQule authorizing and approving ArQule's execution,
delivery and performance of this Agreement, all matters in connection with this
Agreement, and the transactions contemplated thereby.

                     (b)  a certificate, executed by the duly authorized officer
of ArQule as of the Closing Date, certifying to the fulfillment of all of the
conditions to Pfizer's obligations under this Agreement, as set forth in this
Section 6.

           6.5       OTHER MATTERS. All corporate and other proceedings in
connection with the transactions contemplated at the Closing by this Agreement,
and all documents and instruments incident to such transactions, shall be
reasonably satisfactory in substance and form to Pfizer and its counsel, and
Pfizer and its counsel shall have received all such counterpart originals or
certified or other copies of such documents as they may reasonably request.

     SECTION 7.      CONDITIONS TO THE OBLIGATIONS OF ARQULE.

           The obligation of ArQule to issue and sell the Shares at the
Closing is subject to the fulfillment, or the waiver by ArQule, of the
conditions set forth in this Section 7 on or before the Closing Date.

           7.1       ACCURACY OF REPRESENTATIONS AND WARRANTIES. Each
representation and warranty of Pfizer contained in this Agreement shall be true
on and as of the Closing Date with the same effect as though such
representations and warranties had been made on and as of that date.

           7.2       CERTIFICATES AND DOCUMENTS. Pfizer shall have delivered to
counsel to ArQule:

                     (a)  a certificate of the Secretary or Assistant Secretary
of Pfizer dated as of the Closing Date, certifying as to (i) the incumbency of
officers of Pfizer executing this Agreement and all other documents executed and
delivered in connection herewith. (b) a certificate, executed by a duly
authorized officer of Pfizer as of the Closing Date, certifying to the
fulfillment of all of the conditions to ArQule's obligations under this
Agreement, as set forth in this Section 7.

                                       5
<Page>

           7.3       PERFORMANCE. Pfizer shall have performed and complied with
all agreements and conditions contained in this Agreement required to be
performed or complied with by Pfizer prior to or at the Closing.

           7.4       OTHER MATTERS. All corporate and other proceedings in
connection with the transactions contemplated at the Closing by this Agreement,
and all documents and instruments incident to such transactions, shall be
reasonably satisfactory in substance and form to ArQule and its counsel, and
ArQule and its counsel shall have received all such counterpart originals or
certified or other copies of such documents as they may reasonably request.

     SECTION 8.      SURVIVAL OF REPRESENTATIONS, WARRANTIES AND AGREEMENTS;
ASSIGNABILITY OF RIGHTS. Notwithstanding any investigation made by any party to
this Agreement, all covenants, agreements, representations and warranties made
by ArQule and Pfizer herein, except as otherwise expressly provided herein,
shall terminate upon the delivery to Pfizer of the Shares being purchased and
the payment therefor. Except as otherwise provided herein, (i) the covenants,
agreements, representations and warranties of ArQule made herein shall bind
ArQule's successors and assigns and shall inure to the benefit of Pfizer's
successors and assigns and (ii) the covenants, agreements, representations and
warranties of Pfizer made herein shall bind Pfizer's successors and assigns and
shall inure to the benefit of ArQule's successors and assigns.

     SECTION 9.      INCIDENTAL REGISTRATION.

     For the purpose of this Section 9, the term "Registrable Shares" shall
mean (i) all Shares, and (ii) Common Stock issued pursuant to stock splits,
stock dividends and similar distributions with respect to such Shares. The term
"Registration Statement" shall mean any Registration Statement filed by ArQule
under the Securities Act for the offer and sale by ArQule in a public offering
of not less than $5 million of Common Stock, which shall not include any
offering made in connection with a business combination transaction or employee
benefit plan.

           9.1       REGISTRATION OF SHARES. ArQule covenants and agrees that it
will:

                     (a)  Whenever ArQule proposes to file a Registration
Statement, prior to such filing it shall give reasonable advance written notice
to Pfizer of its intention to do so, and upon the written request of Pfizer
which shall be given no later than 30 days after ArQule provides such notice
(which request shall state the intended method of disposition of such
Registrable Shares), ArQule shall use its best efforts to cause all Registrable
Shares which ArQule has been requested to register to be registered under the
Securities Act to the extent necessary to permit their sale or other disposition
in accordance with the intended methods of distribution specified in the request
of Pfizer; PROVIDED that: (i) ArQule shall not be required to make more than
four (4) such registrations pursuant to this Section 9.1; (ii) ArQule shall have
the right to postpone or withdraw any registration effected pursuant to this
Section 9.1(a) without obligation or liability to any stockholder and (iii)
ArQule shall have the right to postpone or withdraw any registration effected
pursuant to this Section 9 without obligation to Pfizer (except that such
registration shall not count as one of the two requests permitted under clause
(i)) if, in the reasonable opinion of the Board of Directors of ArQule, such
registration statement would be materially detrimental to ArQule.

                     (b)  In connection with any offering under this Section 9
involving an underwriter, and subject to the next sentence hereof, ArQule shall
not be required to include any Registrable Shares in such underwritten public
offer in such quantity as will, in the reasonable opinion of the managing
underwriter, jeopardize the success of the offering by ArQule or materially
adversely affect the price receivable by ArQule in such offering. If in the
opinion of the managing underwriter the registration of all, or part of, the
Registrable Shares which Pfizer has requested to be included would materially
and adversely affect the success or the price receivable in such public

                                       6
<Page>

offering, then ArQule shall be required to include in the underwriting only that
number of Registrable Shares, if any, which the managing underwriter believes
may be sold without causing such a material adverse effect; PROVIDED that any
such number of Registrable Shares that ArQule shall be required to include in
the underwriting shall be allocated, among Pfizer and the other holders, if any,
that then have a right to request, and have requested, Registrable Shares to be
included in the underwriting, in proportion, as nearly as practicable, to the
respective amounts of Registrable Shares which Pfizer and each such other holder
has requested to be included in the underwriting.

           9.2       ALLOCATION OF EXPENSES. ArQule shall pay the reasonable and
actual Registration Expenses for all registrations pursuant to this Agreement.
For purposes of this Section, the term "Registration Expenses" shall mean all
expenses incurred by ArQule in complying with this Agreement, including, without
limitation, all registration and filing fees, exchange listing fees, printing
expenses, fees and disbursements of counsel for ArQule, out-of-pocket expenses
of ArQule and the underwriters, state Blue Sky fees and expenses, and the
expense of any special audits incident to or required by any such registration,
but excluding underwriting discount and selling commissions Such underwriting
discounts and selling commissions shall be borne pro rata by the selling holders
in accordance with the number of shares of their Common Stock included in such
registration.

           9.3       CESSATION OF SALES. In the event of any registration of
Registrable Shares under the Securities Act pursuant to this Agreement, Pfizer
agrees that, upon receipt of any notice from ArQule of (i) any request by the
SEC for amendments or supplements to a Registration Statement or related
prospectus covering any of Pfizer's Registrable Shares, (ii) the issuance by the
SEC of any stop order suspending the effectiveness of a Registration Statement
covering any of Pfizer's Registrable Shares or the initiation of any proceedings
for that purpose, (iii) the receipt by ArQule of any notification with respect
to the suspension of the qualification of any Registrable Shares for sale in any
jurisdiction or the initiation or threatening of any proceeding for such
purpose, (iv) the happening of any event that requires amending or supplementing
the Registration Statement, prospectus, prospectus supplement or post-effective
amendment so that any of the foregoing will not contain any untrue statement of
a material fact or omit to state any material fact necessary in order to make
the statements therein, in light of the circumstances under which they are made,
not misleading, or (v) ArQule's reasonable determination that a post-effective
amendment to the Registration Statement or a supplement to any related
prospectus is required under the Securities Act; Pfizer will immediately
discontinue disposition of such Registrable Shares. Pfizer further agrees that
(x) it shall not resume its disposition of Registrable Shares pursuant to such
Registration Statement or related prospectus unless it has received notice from
ArQule that such Registration Statement or amendment has become effective under
the Securities Act and has received a copy or copies of the related prospectus
(as then amended or supplemented, as the case may be), unless the Registrable
Shares are then listed on a national securities exchange and ArQule has advised
Pfizer that ArQule has delivered copies of the related prospectus, as then
amended or supplemented, to such exchange and (y) if so directed by ArQule, such
holder will deliver to ArQule (at ArQule's expense) all copies, other than
permanent file copies then in such stockholder's possession, of the prospectus
covering such Registrable Shares current at the time of receipt of such notice.

           9.4       INDEMNIFICATION.

                     (a)  In the event of any registration of any of the
Registrable Shares under the Securities Act pursuant to this Agreement, then to
the extent permitted by law ArQule shall indemnify and hold harmless Pfizer and
each of its officers, directors and employees of Pfizer, if any, each
underwriter of such Registrable Shares and each other persons, if any, who
controls Pfizer or such underwriter within the meaning of the Securities Act or
the Exchange Act against any losses, claims, damages, expenses or liabilities,
joint or several, to which Pfizer, such underwriter or controlling person may
become subject under the Securities Act, the Exchange Act, state securities laws
or otherwise, insofar as such losses, claims, damages or liabilities (or actions
in respect thereto) arise out of or are based upon any untrue statement or
alleged untrue statement of any material fact contained in any Registration
Statement under which such Registrable Shares were registered under the
Securities Act, or any preliminary prospectus or final prospectus contained in
the Registration Statement, or any amendment or supplement to such Registration
Statement, or arise out of or are based upon the omission or alleged omission to

                                        7
<Page>

state a material fact required to be stated therein or necessary to make the
statements therein not misleading; and ArQule shall reimburse Pfizer, such
underwriter and each such controlling person for any legal or any other expenses
reasonably incurred by Pfizer, such underwriter or controlling person in
connection with investigating or defending any such loss, claim, damage,
liability or action; PROVIDED, HOWEVER, that ArQule shall not be liable in any
such cases to the extent that such loss, claim, damage or liability arises out
of or is based upon any untrue statement or omission made in such Registration
Statement, preliminary prospectus or prospectus, or any such amendment or
supplement, in reliance upon and in conformity with information furnished to
ArQule, in writing, by or on behalf of Pfizer, such underwriter or controlling
person specifically for use in the preparation thereof.

                     (b)  In the event of any registration of any of the
Registrable Shares under the Securities Act pursuant to this Agreement, then to
the extent permitted by law, Pfizer and each other seller, if any, of
Registrable Shares, severally and not jointly, shall indemnify and hold harmless
ArQule, each of its directors, officers and employees, and each underwriter (if
any) and each person, if any, who controls ArQule or any such underwriter within
the meaning of the Securities Act or the Exchange Act against any losses,
claims, damages or liabilities joint or several, to which ArQule, such directors
and officers, underwriter or controlling person may become subject under the
Securities Act, the Exchange Act, state securities laws or otherwise, insofar as
such losses, claims, damages or liabilities (or actions in respect thereto)
arise out of or are based upon any untrue statement or alleged untrue statement
of a material fact contained in any Registration Statement under which
Registrable Shares were registered under the Securities Act, any preliminary
prospectus or final prospectus contained in the Registration Statement, or any
amendment or supplement to the Registration Statement, or arise out of or are
based upon any omission or alleged omission to state a material fact required to
be stated therein or necessary to make the statements therein not misleading, if
the statement or omission was made in reliance upon and in conformity with
information furnished in writing to ArQule by such seller specifically for use
in connection with the preparation of such Registration Statement, prospectus,
amendment or supplement; PROVIDED, HOWEVER, that the obligations of Pfizer
hereunder shall be limited to an amount equal to the proceeds to Pfizer of
Registrable Shares sold as contemplated herein.

                     (c)  Indemnifications of an underwriter pursuant to this
Section 9.4 shall not be interpreted as providing relief of such underwriter
from any or all of its due diligence obligations. Further, an underwriter shall
not be entitled to indemnification pursuant to this section in the event that it
fails to deliver to any seller of Registrable Shares any preliminary or final or
revised prospectus, as required by the Rules and Regulations of the Commission.
Finally, no indemnification shall be provided pursuant to this Section in the
event that any error in a preliminary prospectus of ArQule is subsequently
corrected in the final prospectus of ArQule for a particular offering, and such
final prospectus is delivered to the person seeking indemnity, in the case of a
claim made under Section 9.4(a), or to all purchasers in the offering by ArQule
in the case of a claim under Section 9.4(b) prior to the date of purchase of the
securities.

                     (d)  Each party entitled to indemnification under this
Section 9.4 (the Indemnified Party) shall give notice to the party required to
provide indemnification (the Indemnifying Party) promptly after such Indemnified
Party has been given notice of a claim as to which indemnity may be sought, and
shall permit the Indemnifying Party to assume the defense of any such claim or
any litigation resulting therefrom, PROVIDED that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not be unreasonably
withheld or delayed); and, PROVIDED, FURTHER, that the failure of any
Indemnified Party to give notice as provided therein shall not relieve the
Indemnifying Party of its obligations under this Agreement except to the extent
actually prejudiced. The Indemnified Party may participate in such defense at
such Indemnified Party's expense, PROVIDED, HOWEVER, that the Indemnifying Party
shall pay such expense if representation of such Indemnified Party by the
counsel retained by the Indemnifying Party would be inappropriate due to actual
or potential differing interest between the Indemnified Party and any other
party represented by such counsel in such proceeding. No Indemnifying Party, in
the defense of any such claim or litigation shall, except with the consent of
each Indemnified Party, consent to entry of any judgment or enter into any
settlement.

                                       8
<Page>

                     (e)  If the indemnity and reimbursement obligation provided
for in this Section 9.4 is unavailable or insufficient to hold harmless a party
entitled to indemnification in respect of any losses, claims, damages or
liabilities (or actions or proceedings in respect thereof) referred to therein,
then the indemnifying party shall contribute to the amount paid or payable by
the indemnified party as a result of such losses, claims, damages or liabilities
(or actions or proceedings in respect thereof) in such proportion as is
appropriate to reflect the relative fault of the indemnifying party on the one
hand and the indemnified party on the other hand in connection with statements
or omissions which resulted in such losses, claims, damages or liabilities, as
well as any other relevant equitable considerations. The relative fault shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission or alleged omission to state
a material fact relates to information supplied by the indemnifying party or the
indemnified party and the parties' relative intent, knowledge, access to
information and opportunity to correct or prevent such untrue statement or
omission. The parties hereto agree that it would not be just and equitable if
contributions pursuant to this section were to be determined by PRO RATA
allocation or by any other method of allocation which does not take account of
the equitable considerations referred to in the first sentence of this section.
The amount paid by an indemnified party as a result of the losses, claims,
damages or liabilities referred to in the first sentence of this Section 9.4(d)
shall be deemed to include any legal and other expenses reasonably incurred by
such indemnified party in connection with investigating or defending any losses,
claims, damages or liabilities which is the subject of this Section 9.4(d).

                     (f)  No indemnified party guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from the indemnifying party if the
indemnifying party was not guilty of such fraudulent misrepresentation.

           9.5       TERMINATION. Pfizer's incidental registration rights
hereunder shall terminate as to any Shares upon the earlier of (i) when the
Shares may be sold by Pfizer under Rule 144(k) under the Securities Act, or (ii)
such time as no such Shares are held by Pfizer.

     SECTION 10.     COVENANTS OF PFIZER AND ARQULE.

          10.1       STANDSTILL AGREEMENT.

                     (a)  CERTAIN DEFINITIONS Unless the context otherwise
requires, the following terms, for all purposes of this Section 10, shall have
the meanings specified in this Section 10.1(a):

           "Affiliate" shall mean any entity which controls, is controlled by or
           is under common control with Pfizer. A corporation or other entity
           shall be regarded as in control of another corporation or entity if
           it owns or directly or indirectly controls more than fifty percent
           (50%) of the outstanding voting stock or other ownership interest of
           the other corporation or entity, or if it possesses, directly or
           indirectly, the power to manage, direct or cause the direction of the
           management and policies of the corporation or other entity or the
           power to elect or appoint fifty percent (50%) or more of the members
           of the governing body of the corporation or other entity. Any such
           other relationship as in fact results in actual control over the
           management, business and affairs of a corporation or other entity
           shall also be deemed to constitute control.

           "Change of Control" shall mean (i) the acquisition by any person or
           entity (other than ArQule, any subsidiary of ArQule, any employee
           benefit plan of ArQule, or any entity organized, appointed or
           established by ArQule holding securities of ArQule pursuant to such
           benefit plan) directly or indirectly, of securities, or the rights to
           acquire securities, representing 50% or more of the combined voting
           power of ArQule's then outstanding securities; or (ii) a merger or
           consolidation of ArQule with any other corporation, other than (a) a
           merger or consolidation which would result in the voting securities
           of ArQule outstanding immediately prior thereto continuing to
           represent

                                       9
<Page>

           (either by remaining outstanding or by being converted into voting
           securities of the surviving entity) at least 50% of the combined
           voting securities of ArQule or such surviving entity outstanding
           immediately after such merger or consolidation or (b) a merger or
           consolidation effected to implement a recapitalization of ArQule (or
           similar transaction) which does not otherwise constitute a Change in
           Control.

           "Maximum Percentage" shall mean 10%.

           "Outstanding Voting Stock" of ArQule, or another entity as the
           context requires, shall mean (i) the Common Stock or other securities
           of ArQule (or such other entity) then outstanding and (ii) any other
           securities convertible into Common Stock of ArQule (or such other
           entity) then outstanding, having the power to vote on any matter
           brought before shareholders at a meeting or by written consent, other
           than securities having such power only upon the happening of a
           contingency which has not yet occurred.

           "Voting Power" shall mean the number of votes entitled to then be
           cast by the Outstanding Voting Stock of ArQule at any election of
           directors of ArQule.

           "Voting Stock" shall mean the Common Stock outstanding, assuming the
           exercise or conversion of all outstanding securities convertible into
           or exercisable or exchangeable for Common Stock and any other
           securities issued by ArQule having the power to vote in the election
           of directors of ArQule other than securities having such power only
           upon the happening of a contingency which has not yet occurred.

                     (b)  PROHIBITED ACQUISITIONS. Pfizer agrees that, for a
period of [four(4)] years following the Closing Date, unless it has obtained the
prior written consent of ArQule, it will not directly or indirectly (i) acquire
beneficial ownership of any Voting Stock, any securities convertible into or
exchangeable for Voting Stock, or any other right to acquire Voting Stock
(except by way of stock dividends or other distributions or offerings made
available to holders of any Voting Stock generally or additional purchased
Voting Stock as set forth in the Collaboration Agreement), (ii) make a tender,
exchange or other offer for Voting Stock which would result in such an
acquisition, or (iii) engage in any solicitation of proxies (within the meaning
of the federal securities laws) for the purpose of obtaining shareholder
approval for any transaction that would result in such an acquisition, if the
effect of such acquisition would be to increase the Voting Power of all Voting
Stock then beneficially owned by Pfizer, or which Pfizer has a right to acquire,
to an aggregate number of shares exceeding the Maximum Percentage of the total
Voting Power of ArQule at the time in effect; PROVIDED that it will not be a
violation of this Section 10.1 if the aggregate percentage of the total Voting
Power of ArQule represented by Voting Stock beneficially owned by Pfizer or
which Pfizer has a right to acquire is increased as a result of a
recapitalization of ArQule on or after the date of this Agreement, repurchase by
ArQule of any of its Common Stock or any other action taken by ArQule or its
affiliates. In the event that Pfizer owns in the aggregate more than the Maximum
Percentage of the total Voting Power of ArQule due to a repurchase by ArQule of
any of its Common Stock Pfizer may, but is not required to request that ArQule
repurchase that number of shares of its Common Stock from Pfizer necessary to
reduce Pfizer's ownership of ArQule's Common Stock below the Maximum Percentage,
at the current market price; PROVIDED, HOWEVER,

                                       10
<Page>

that the foregoing shall not be deemed to limit ArQule's remedies in the event
that the excess Voting Stock is acquired in violation of this Section 10.1(b).

                     (c)  EXCEPTIONS. The parties agree that the restrictions
set forth in Section 10.1(b) above shall not apply (a) if a public announcement
is made of (i) the commencement of, or an intention to commence or make, a
tender offer or exchange offer by any person other than Pfizer or an Affiliate
for Voting Stock or (ii) a proposal of any business combination to effect a
Change of Control of ArQule by any person other than Pfizer or an Affiliate or
(b) Pfizer acquires Voting Stock as a result of the combination of Pfizer or an
Affiliate with, or the acquisition by Pfizer or any Affiliate of, another
entity.

                     (d)  PROHIBITED TRANSFER. Any purchase which causes Pfizer
to be in violation of the terms of Section 10.1(b) above shall not be effected
by ArQule and shall be voidable at the option of ArQule by its giving written
notice to the transferor, his transferee and Pfizer.

                     (e)  AFFILIATES OF PFIZER. Pfizer represents to ArQule that
there is no Affiliate which, as of the date of this Agreement, owns of record or
beneficially any (i) Voting Stock, or (ii) any other securities convertible or
exchangeable (with or without the payment of additional consideration) into
Voting Stock of ArQule. Pfizer covenants to ArQule that, if at any time while
this Section 10.1 is in effect, any Affiliate of Pfizer becomes or intends to
become the beneficial owner, as defined in regulations promulgated by the
Securities and Exchange Commission, of any Voting Stock, or any securities
convertible or exchangeable into Voting Stock, Pfizer will, whether prior to
such ownership if possible, or, if not possible, as soon as practicable after
such ownership, cause such Affiliate to agree to be bound by Section 10.1 of
this Agreement.

           10.2      INFORMATION BY HOLDER. Each holder of Registrable Shares
included in any Registration shall furnish to ArQule such information regarding
such holder and the distribution proposed by such holder as ArQule may request
in writing and as shall be required in connection with any registration,
qualification or compliance referred to in Article 9.

           10.3      "STAND-OFF" AGREEMENT. Pfizer, if requested by ArQule and
an underwriter of Common Stock or other securities of ArQule, shall agree not to
sell otherwise transfer or dispose of any Registrable Shares or other securities
of ArQule held by such Stockholder for a specified period of time (not to exceed
90 days) following the effective date of a Registration Statement; PROVIDED that
all executive officers and directors of ArQule enter into similar agreements.
Such agreement shall be in writing in a form satisfactory to ArQule and such
underwriter. ArQule may impose stop-transfer instructions with respect to the
Registrable Shares or other securities subject to the foregoing restriction
until the end of the stand-off period.

           10.4      TERM. Except as otherwise expressly provided herein, the
provisions of this Section 10 shall terminate and be of no further force and
effect upon the date five years after the Closing Date.

     SECTION 11.     MISCELLANEOUS.

                                       11
<Page>

           11.1      NOTICES. Any consent, notice or report required or
permitted to be given or made under this Agreement by one of the parties hereto
to the other shall be in writing, delivered personally or by facsimile (and
promptly confirmed by telephone, personal delivery or courier) or courier,
postage prepaid (where applicable), addressed to such other party at its address
indicated below, or to such other address as the addressee shall have last
furnished in writing to the addressor and shall be effective upon receipt by the
addressee.

     If to ArQule:   ArQule, Inc.
                     19 Presidential Way
                     Woburn, MA 01801
                     Attention: Chief Executive Officer
                     Copy to: General Counsel

                     Telephone:       781-994-0300
                     Telecopy:        781-994-0587

                     with a copy to:

                     Arnold & Porter
                     1600 Tysons Boulevard
                     Suite 900
                     McLean, VA 22102
                     Attention:  Steve Parker, Esq.

     If to Pfizer:   Pfizer Global Research and Development
                     50 Pequot Avenue
                     New London, CT 06320
                     Attention: Vice President of Strategic Alliances
                     Copy to: Assistant General Counsel PGRD

                     Telephone:       860-441-8014
                     Telecopy:        860-441-1738

           11.2      ENTIRE AGREEMENT. This Agreement contains the entire
understanding of the parties with respect to the subject matter hereof. All
express or implied agreements and understandings, either oral or written,
heretofore made are expressly merged in and made a part of this Agreement.

           11.3      ASSIGNMENT. Neither this Agreement nor any of the rights
and obligations contained herein may be assigned or otherwise transferred by
either party without the consent of the other party; PROVIDED, HOWEVER, that
either ArQule or Pfizer may, without such consent, assign its rights and
obligations under this Agreement (i) to any Affiliate, all or substantially all
of the equity interest of which is owned and controlled by such party or its
direct or indirect parent corporation, or (ii) in connection with a merger,
consolidation or sale of substantially all of such party's assets to an
unrelated third party; PROVIDED FURTHER, that such party's rights and
obligations under this Agreement shall be assumed by its successor in interest
in any such transaction and shall not be transferred separate from all or
substantially all of its other business assets, including those business assets.
Any purported assignment in violation of the preceding sentence shall be void.
Any permitted assignee shall assume all obligations of its assignor under this
Agreement.

           11.4      AMENDMENTS AND WAIVERS. This Agreement may not be modified
or amended except pursuant to an instrument in writing signed by ArQule and
Pfizer. The waiver by either party hereto of any right

                                       12
<Page>

hereunder or the failure to perform or of a breach by the other party shall not
be deemed a waiver of any other right hereunder or of any other breach or
failure by said other party whether of a similar nature or otherwise.

           11.5      HEADINGS. The headings of the various sections of this
Agreement have been inserted for convenience of reference only and shall not be
deemed to be part of this Agreement.

           11.6      SEVERABILITY. In case any provision contained in this
Agreement should be invalid, illegal or unenforceable in any respect, the
validity, legality and enforceability of the remaining provisions contained
herein shall not in any way be affected or impaired thereby.

           11.7      GOVERNING LAW. This Agreement shall be governed by and
construed in accordance with the laws of the State of New York (without giving
effect to the choice of law provisions thereof) and the federal law of the
United States of America.

           11.8      COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall constitute an original, but all of which, when
taken together, shall constitute but one instrument, and shall become effective
when one or more counterparts have been signed by each party hereto and
delivered to the other parties.

           11.9      EXPENSES. Except as otherwise specifically provided herein,
each party shall bear its own expenses in connection with this Agreement.

           11.10     PUBLICITY. Neither party hereto shall issue any press
releases or otherwise make any public statement with respect to the transactions
contemplated by this Agreement without the prior consent of the other party
which shall not be unreasonably withheld, except as may be required by
applicable law or regulation.

     SECTION 12.     DEFINITIONS. The following terms are defined in the
Sections indicated:

<Table>
           <S>                                             <C>
           Affiliate........................................10.1(a)

           Aggregate Purchase Price...............................2

           Agreement.......................................Preamble

           ArQule..........................................Preamble

           ArQule Subsidiary....................................4.3

           Change of Control................................10.1(a)

           Closing................................................3

           Closing Date...........................................3

           Collaboration Agreement..........................Recital

           Common Stock...........................................1

           Company.........................................Preamble

           Exchange Act.........................................4.8

           Material Adverse Effect..............................4.1

           Maximum Percentage...............................10.1(a)

           Outstanding Voting Stock.........................10.1(a)
</Table>

                                       13
<Page>

<Table>
           <S>                                             <C>
           Pfizer..........................................Preamble

           Pfizer Subsidiary....................................5.2

           Preferred Stock......................................4.2

           Registrable Shares.....................................9

           Registration Expenses................................9.2

           Registration Statement.................................9

           SEC..................................................4.2

           Securities Act.......................................4.5

           Voting Power.....................................10.1(a)

           Voting Stock.....................................10.1(a)
</Table>

            [The remainder of this page is intentionally left blank]

                                       14
<Page>

     IN WITNESS WHEREOF, the parties hereto have caused this Common Stock
Purchase Agreement to be executed by their duly authorized representatives as of
the day and year first above written.

                                  ARQULE, INC.

                                  By:
                                     -------------------------------------
                                     By:     Stephen A. Hill
                                     Title:  President and Chief Executive
                                             Officer

                                  PFIZER HOLDINGS EUROPE

                                  By:
                                     --------------------------------------
                                     By:
                                     Title:

                                       15<Page>

                                                                     EXHIBIT 4.4

                      FORM OF FIRST SUPPLEMENTAL INDENTURE
--------------------------------------------------------------------------------

                          BOSTON SCIENTIFIC CORPORATION

                                              AS ISSUER

                               JPMORGAN CHASE BANK
                        (f/k/a The Chase Manhattan Bank)

                                             AS TRUSTEE

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

                          First Supplemental Indenture

                          Dated as of December 6, 2001

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

                                  $500,000,000

                         6 5/8% Notes due March 15, 2005

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

<Page>

                          FIRST SUPPLEMENTAL INDENTURE

          First Supplemental Indenture (this "Supplemental Indenture") dated as
of December 6, 2001 between BOSTON SCIENTIFIC CORPORATION, a Delaware
corporation (the "Company"), and JPMORGAN CHASE BANK (f/k/a The Chase Manhattan
Bank), as Trustee (the "Trustee").

                                   WITNESSETH:

          WHEREAS, in accordance with Section 902 of the Indenture relating to
the 6[SYMBOL]% Notes due 2005 of the Company (the "Securities"), dated as of
September 1, 1997 (the "Indenture"), the Trustee, the Company and the Holders of
at least a majority in principal amount at maturity of the Securities
outstanding as of the date hereof desire to amend certain terms of the Indenture
as described below;

          WHEREAS, the Company intends to increase its financing flexibility to
permit, among other things, an increased ability to secure its payment
obligations with respect to possible future financings of the accounts
receivable of the Company or its subsidiaries;

          WHEREAS, in accordance with the terms of the Indenture, Holders of or
in excess of a majority in aggregate principal amount of the outstanding
Securities have consented to the amendments set forth herein;

          WHEREAS, the execution and delivery of this Supplemental Indenture has
been duly authorized by the parties hereto and the Trustee has received an
Opinion of Counsel pursuant to Section 903 of the Indenture, and all other acts
necessary to make this Supplemental Indenture a valid and binding supplement to
the Indenture and effectively amending the Indenture as set forth herein have
been duly taken;

          NOW, THEREFORE, the parties hereto agree as follows:

          SECTION 101. DEFINITIONS.

          All capitalized terms used and not defined herein shall have the
meanings ascribed thereto in the Indenture.

          SECTION 201. AMENDMENTS TO THE INDENTURE.

          Subject to Section 301 hereof, the Indenture is hereby amended as
follows:

          (a)   AMENDMENT TO SECTION 101. Section 101 of the Indenture is hereby
amended by adding the following definitions:

          "CONSOLIDATED TANGIBLE ASSETS": at any date, Consolidated Total Assets
minus (without duplication) the net book value of all assets which would be
treated as intangible assets, as determined on a consolidated basis in
accordance with GAAP.

<Page>

          "CONSOLIDATED TOTAL ASSETS": at any date, the net book value of all
assets of the Company and its Subsidiaries as determined on a consolidated basis
in accordance with GAAP.

          "RECEIVABLES": any accounts receivable of any Person, including,
without limitation, any thereof constituting or evidenced by chattel paper,
instruments or general intangibles, and all proceeds thereof and rights
(contractual and other) and collateral related thereto.

          "RECEIVABLES TRANSACTION": any transactions or series of related
transactions providing for the financing of Receivables of the Company or any of
its Subsidiaries.

          (b)   AMENDMENT TO SECTION 1009. Section 1009 of the Indenture is
hereby amended by deleting the "." from the end of clause (i) thereof and
substituting in lieu thereof the following:

          ";(j) Liens pursuant to any Receivables Transactions in an aggregate
     principal amount not exceeding 15% of Consolidated Tangible Assets."

          SECTION 301. CONFIRMATION; EFFECTIVENESS. As amended by this
Supplemental Indenture, the Indenture and the Securities are ratified and
confirmed in all respects and the Indenture as so amended shall be read, taken
and construed as one and the same instrument. The provisions of this
Supplemental Indenture shall become operative as of the date of this
Supplemental Indenture. This Supplemental Indenture may be executed in any
number of counterparts, each of which counterparts together shall constitute but
one and the same instrument.

          SECTION 401. TRUST INDENTURE ACT. If and to the extent that any
provision of this Supplemental Indenture limits, qualifies or conflicts with
another provision included in this Supplemental Indenture or in the Indenture,
which is required to be included in this Supplemental Indenture or the Indenture
by the Trust Indenture Act of 1939, as amended (the "TIA"), such required
provision of the TIA shall control.

          SECTION 501. GOVERNING LAW. This Supplemental Indenture shall be
deemed governed by the internal laws of the State of New York.

          SECTION 601. RIGHTS OF TRUSTEE. Without limiting any other protections
or rights afforded the Trustee at law, by contract or otherwise, the Trustee
will be entitled to the full benefits afforded by Sections 602 and 603 of the
Indenture in connection with its execution and delivery of this Supplemental
Indenture.

                                        2
<Page>

          IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the date first written above.

                                            BOSTON SCIENTIFIC CORPORATION

                                            By:
                                                --------------------------------
                                                Title:

                                            JPMORGAN CHASE BANK (f/k/a The Chase
                                               Manhattan Bank), as Trustee

                                             By:
                                                --------------------------------
                                                Title:

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00035-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00035-of-00352.parquet"}]]