EXHIBIT NO. 10.3

   CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND
                EXCHANGE COMMISSION. ASTERISKS DENOTE OMISSIONS.

             FIRST AMENDMENT TO COLLABORATION AND LICENSE AGREEMENT

         This First Amendment to Collaboration and License Agreement (the "First
Amendment") dated as of June 29, 2001 (the "First Amendment Effective Date"), is
by and between Millennium Pharmaceuticals, Inc., a corporation organized and
existing under the laws of the State of Delaware and having its principal office
at 75 Sidney Street, Cambridge, Massachusetts 02139 ("Millennium") and Aventis
Pharmaceuticals Inc., a corporation organized and existing under the laws of the
State of Delaware and having its principal office at Route 202-206, P.O. Box
6800, Bridgewater, New Jersey 08807 ("Aventis").


                                  INTRODUCTION

         WHEREAS, Millennium and Aventis are Parties to a Collaboration and
License Agreement, having an Execution Date of June 22, 2000 (the "Collaboration
Agreement"); and

         WHEREAS, Millennium and Aventis have determined that it is desirable to
amend and restate certain provisions of the Collaboration Agreement as set forth
herein, and incorporate additional provisions to the Collaboration Agreement as
set forth herein, to reflect further agreements between them.

         NOW, THEREFORE, the Parties hereto, intending to be legally bound, and
for good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, hereby agree as follows:

The following definitions shall be added to the Collaboration Agreement or
amended, as the case may be. Capitalized terms used in this Amendment and not
defined herein shall have the meanings ascribed to them in the Collaboration
Agreement.

1.       Section 1.1 of the Collaboration Agreement is hereby amended and
         restated to read in its entirety as follows:

         "ACTIVE". Active means, (a) with respect to a Small Molecule[**] of a
         Scientifically-Qualified Target, that the Small Molecule [**] in the
         case of [**] the Scientifically-Qualified Target with [**] and (b) with
         respect to a Small Molecule[**] of a Program Target, that the Small
         Molecule [**] in the case of [**] a Program Target with [**] set forth
         in the applicable Lead Generation Plan.

2.       Section 1.37 of the Collaboration Agreement is hereby amended and
         restated to read in its entirety as follows:

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         "LEAD COMPOUND FAMILY". Lead Compound Family means, with respect to a
         Lead Compound, such Lead Compound and (i) [**] designated by the JRC
         pursuant to the procedures set forth in the Section 7.1(a) of the
         Chemistry SOP, and (ii) all Program Compounds that are [**] of such
         Lead Compound in the conduct of the Research Program.

         Article 1 of the Collaboration Agreement is hereby amended to add the
         following additional defined terms:

         "CHEMICAL LIBRARY".  Chemical Library means those libraries of Small
         Molecule compounds Controlled by a Party and made available for the
         Research Program.

         "CHEMISTRY SOP". Chemistry SOP means the guidelines and procedures set
         forth in Exhibit A to this First Amendment, as amended from time to
         time by the JRC.

         "CORPORATE DATABASE". Corporate Database means the database of Small
         Molecule compounds and other compounds maintained by each Party which
         database records relevant information (such as, for example, structural
         information) pertaining to such Small Molecules and other compounds,
         including without limitation, Small Molecules identified during the
         Research Program.

         "CORPORATE IDENTIFICATION NUMBER". Corporate Identification Number
         means the unique number used by a Party to identify a specific Small
         Molecule or other compound within its Corporate Database.

         "DATABASE FLAG". Database Flag means a descriptor identifying a
         compound to be part of the Research Program and the status of that
         Small Molecule in the Research Program, [**] in the Research Program.
         As of the First Amendment Effective Date, the Database Flags in-use by
         the Parties are:

                  DEDC:  The Small Molecule is a Dropped EDC Compound.

                  EDC:  The Small Molecule is an Early Development Candidate.

                  EDC BACK-UP: The Small Molecule is identified as a Back-Up
                  Compound in the EDC Data Package.

                  EDC FAMILY: The Small Molecule is identified as a member of an
                  EDC Family in the EDC Data Package.

                  HEP-ROOT: The Small Molecule is a [**] which is used as the
                  basis for the formulation of a HEP Research Plan (as defined
                  in the Chemistry SOP).

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                  JDC:  The Small Molecule is a Joint Development Compound.

                  LC:  The Small Molecule is a Lead Compound.

                  LCF:  The Small Molecule is a member of the Lead Compound
                  Family.

                  PC:  The Small Molecule is a Program Compound.

                  PCF:  The Small Molecule is a member of the Program Compound
                  Family.

                  [**]UDC:  The Small Molecule is a Unilateral Development
                  Compound.

                  Additional Database Flags may be designated from time-to-time
                  on an as-needed basis upon the approval of the JRC.


         "EDC FAMILY". EDC Family means [**], which are selected by the JRC with
         guidance from the Joint Research Project Team and the Joint Chemistry
         Committee.

         "INTERNAL CLEARANCE".  Internal Clearance means the internal process
         conducted by a Party to determine if a specific Small Molecule is
         subject to an Internal Technology Obligation.

         "INTERNAL TECHNOLOGY OBLIGATION". Internal Technology Obligation means,
         with respect to a particular Small Molecule, that such Small Molecule
         has been [**] wherein such [**] (a) [**] pursuant to [**], (b) [**],
         and (c) as of [**] pursuant to the [**].

         "LEAD GENERATION PLAN". Lead Generation Plan means the detailed
         research plan approved by the JRC on a Program Target-by-Program Target
         basis.

         "POSITIVE(S)". Positive means a Small Molecule that is initially
         identified pursuant to the screening of a Chemical Library and which
         meets the criteria for a Positive set forth in the applicable Lead
         Generation Plan.

         "PROGRAM TARGET NOMINATION DATE" Program Target Nomination Date means
         the first date a Party communicates to the JRC (or its designee), such
         Party's interest in designating a particular target as a Program
         Target.
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         [**] means, with respect to a Small Molecule, that (i) it is subject to
         [**], or (ii) in the case of a Small Molecule which is nominated for
         Program Compound status, it is subject to a [**] that such [**] in the
         Research Program.

3.       Section 2.1.1(f) of the Collaboration Agreement is hereby amended to
         read in its entirety as follows:

         It is also intended, notwithstanding subsection (e) above, that during
         the Research Program Term, the Parties shall collaborate in making
         available for the Research Program Small Molecule Chemical Libraries as
         set forth in the then current Annual Research Plan, with the global
         objectives of maximizing the quantity and quality of the EDC Compounds
         with potential utility in the Inflammation Field consistent with the
         resources allocated to such activities under the Annual Research Plan.
         Specific procedures [**] and the provision of information related to
         [**], including, without limitation, [**], are set forth in the [**];
         PROVIDED, THAT, except as otherwise provided in this Collaboration and
         License Agreement, neither Party shall be obligated to disclose to the
         other Party the chemical structure of any compound in any Chemical
         Library Controlled by such Party unless and until such compound is
         identified and confirmed by the Controlling Party to be Active against
         a Program Target and such compound is not subject to [**] asserted by a
         Party, or is otherwise designated a Program Compound by the Joint
         Research Committee.

4.       The second sentence of Section 2.4.1 of the Collaboration Agreement is
         hereby amended to read in its entirety as follows:

         The Parties shall conduct the Research Program in accordance with such
         project progression guidelines, and in accordance with the procedures
         set forth in the Chemistry SOP.

4.       Section 2.4.5 of the Collaboration Agreement is hereby amended by
         adding the following text at the end of Section 2.4.5:

         The Parties shall establish a Joint Chemistry Committee, which shall be
         a sub-committee of the JRC and which shall be responsible for
         implementing the Chemistry SOP during the Research Program. The Joint
         Chemistry Committee shall also be responsible for recommending to the
         JRC revisions to the Chemistry SOP, on an as-needed basis. The Joint
         Chemistry Committee shall be comprised of an equal number of
         representatives from each Party. Each Party shall have one vote on the
         Joint Chemistry Committee, and all decisions of the Joint Chemistry
         Committee must be made by a vote in the affirmative from both Parties.
         If the

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         Joint Chemistry Committee is unable to agree on any decision or
         recommendation before it, the issue shall be resolved by the JRC, and
         if the JRC is unable to reach unanimous agreement on the matter it
         shall be resolved pursuant to Article 12. Except as otherwise provided
         in the immediately preceding five (5) sentences of this Section 2.4.5,
         the Joint Chemistry Committee shall follow the procedures for formation
         and membership, administrative matters, decision making and meetings
         set forth in Section 2.2 hereof.

6.       Section 2.5 of the Collaboration Agreement is hereby amended by adding
         new Section 2.5.6, which shall read in its entirety as follows:

         In the case of a Program Compound, prior to the designation of a Small
         Molecule as a Program Compound by the Joint Research Committee, the
         Parties shall conduct Internal Clearance with respect to such Program
         Compound, as further described in the Chemistry SOP, in order to
         identify any [**] with respect to such Small Molecule. The Parties
         shall also determine if there are any Burdened Technology Obligations
         with respect to the Small Molecule. A proposed Small Molecule will only
         be permitted into the Research Program after it is determined that such
         Small Molecule is not subject to [**] and the JRC has evaluated the
         nature and scope of any Burdened Technology Obligation and accepted
         such compound as a Program Compound.

7.       Section 3.1.1 is hereby amended to read in its entirety as follows:

         The Joint Research Committee shall notify the Joint Development
         Committee in writing when a Joint Research Project Team has recommended
         a Program Compound for EDC Status. Such notification shall (1) identify
         the Program Compound with specificity, (2) identify the related Program
         Target, if any, (3) identify [**] Small Molecules as members of the
         corresponding EDC Family, and (4) identify any existing Back-Up
         Compounds in accordance with Section 3.9. Such notification shall be
         accompanied by any pertinent data, information, results and materials
         relating to the foregoing available to the Joint Research Committee
         (the "EDC Data Package"). In the case where Back-Up Compounds have not
         been identified, the notification shall also include a proposed plan
         for the identification of Back-Up Compounds. With respect to the
         designated members of the EDC Family, such Small Molecules shall be
         designated as members of an EDC Family for [**] such Small Molecules
         [**]: (i) [**], or (ii) the date when [**], or (iii) with respect to a
         particular member of an EDC Family, the Joint Research Committee (JRC)
         determines that [**], it being understood that any such [**] shall only
         occur as otherwise permitted under this Agreement.

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8.       Section 3.9.1 is hereby amended and restated to read in its entirety
         as follows:

         When a Program Compound is nominated for EDC Status, the EDC Data
         Package shall either: (a) identify other Program Compounds which shall
         serve as Back-Up Compounds, or (b) in the case where Back-Up Compounds
         have not been identified, include a proposed plan for the
         identification of Back-Up Compounds. Back-Up Compounds identified or
         to-be-identified shall be based on back-up selection criteria agreed
         upon by the Joint Research Committee pursuant to 2.4.1.

9.       Section 9.1.2(b) is hereby amended and restated to read in its
         entirety as follows:

         COMPOUND RELATED INVENTIONS. In the event a Party [**] in the conduct
         of the Research Program [**], then the Party or Parties, as the case
         may be, shall [**] to the Party or Parties, if any, [**].

10.      The first sentence of Section 2.10.2 of the Collaboration Agreement
         is hereby amended and restated to read in its entirety as follows:

                  Each GT Option and Vaccine Option will expire [**]after the
                  designation of the underlying target as a Program Target by
                  the Joint Research Committee.

11.      The first sentence of Section 2.11.2 of the Collaboration Agreement is
         hereby amended and restated to read in its entirety as follows:

                  Each Antibody Option and Diagnostic Option will expire [**]
                  after the designation of the underlying target as a Program
                  Target by the Joint Research Committee.

CONTINUING EFFECT. Except as specifically modified by this First Amendment, all
of the provisions of the Collaboration Agreement are hereby ratified and
confirmed to be in full force and effect, and shall remain in full force and
effect.

ENTIRE AGREEMENT; SUCCESSORS AND ASSIGNS. The Collaboration and License
Agreement, this First Amendment, and any written agreements executed by both
Parties pertaining to the subject matter therein, constitute the entire
agreement between the Parties hereto with respect to subject matter hereof and
thereof. Said documents supersede all other agreements and understandings
between the Parties with respect to the subject matter hereof and thereof,
whether written or oral. This First Amendment shall

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be binding upon and shall inure to the benefit of the Parties and their
respective heirs, administrators, executors, affiliates, successors and
permitted assigns.

HEADINGS.  The section headings contained in this First Amendment are for
reference purposes only and shall not affect in any way the meaning or
interpretation of the First Amendment.

COUNTERPARTS. This First Amendment may be executed in one or more counterparts,
all of which shall be considered one and the same agreement, and shall become a
binding agreement when one or more counterparts have been signed by each Party
and delivered to the other Party.

MISCELLANEOUS. This First Amendment shall be governed by the laws of the State
of Delaware, without regard to its principles of conflicts of laws. This First
Amendment supercedes all prior understandings and agreements, whether written or
oral, among the Parties hereto relating to the essence of this First Amendment.
If there is a direct conflict between the provisions of the Collaboration and
License Agreement and this First Amendment, this First Amendment shall govern.
This First Amendment may be amended only by a written instrument executed by
each of the Parties.




                      [SIGNATURES APPEAR ON FOLLOWING PAGE]


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         IN WITNESS WHEREOF, each of the Parties has caused this First Amendment
to be executed as of the date hereof by a duly authorized corporate officer.


                                         AVENTIS PHARMACEUTICALS INC.

                                         By: /s/JOHN ZAWAD

                                         Name:  John Zawad

                                         Title: Vice President
                                                Technology Licensing & Alliances

                                         Date: August 29, 2001


                                         MILLENNIUM PHARMACEUTICALS,
                                         INC.


                                         By: /s/ ALAN CRANE

                                         Name:Alan Crane

                                         Title: SVP, Corporate Development

                                         Date: September 4, 2001