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                                                                    EXHIBIT 10.2

                   AGREEMENT AND AMENDMENT TO RIGHTS AGREEMENT

1.    GENERAL BACKGROUND. In accordance with Section 21 of the Rights Agreement
      (the "Agreement") between STATE STREET BANK AND TRUST COMPANY ( "State
      Street Bank") and BIOGEN, INC. ("Biogen") dated May 8, 1999 (the
      "Agreement"), State Street Bank, Biogen and EquiServe Trust Company, N.A.
      ("EquiServe") desire to enter into this Agreement and Amendment in order
      to effect the appointment of EquiServe to replace State Street Bank as
      Rights Agent under the Agreement.

2.    EFFECTIVE DATE. This Agreement and Amendment shall be effective as of May
      31, 2002 (the "Effective Date"). Capitalized terms used herein and not
      defined shall have the meanings ascribed to them in the Agreement.

3.    AGREEMENT. Biogen, State Street Bank and EquiServe hereby agree that
      EquiServe shall be appointed as Rights Agent as of the Effective Date and
      State Street Bank shall resign as Rights Agent immediately upon the
      appointment of EquiServe as Rights Agent. In accordance therewith, Biogen
      hereby appoints EquiServe to act as Rights Agent in accordance with the
      terms and conditions of the Agreement, as amended by this Agreement and
      Amendment, and EquiServe hereby accepts such appointment as of the
      Effective Date. EquiServe represents, warrants and covenants to Biogen
      that it is, and will continue to be for so long as it is Rights Agent, a
      corporation or trust company organized and doing business under the laws
      of the United States, in good standing, which is authorized under such
      laws to exercise corporate trust or stock transfer powers and is subject
      to supervision or examination by federal or state authority and
      individually or combined with an affiliate has a combined capital and
      surplus of at least $100 million dollars. As of the Effective Date,
      EquiServe shall be vested with, and subject to, the same powers, rights,
      duties and responsibilities as if it had been originally named as Rights
      Agent under the Agreement without further act or deed. State Street Bank
      hereby represents, warrants and covenants to Biogen and EquiServe that it
      will deliver and transfer to EquiServe any and all property related to the
      Agreement held by it as of the Effective Date, and execute and deliver any
      further assurance, conveyance, act or deed necessary to effect the purpose
      of this Agreement and Amendment and the appointment of EquiServe as Rights
      Agent in replacement of State Street Bank. State Street Bank represents,
      covenants and warrants to Biogen that it was in full compliance with all
      provisions in the Agreement applicable to it as of the Effective Date.

4.    AMENDMENTS TO THE AGREEMENT.
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      a.    The definition of "Rights Agent" in the first paragraph of the
            Agreement is hereby changed from "State Street Bank and Trust
            Company, a Massachusetts Trust Company" to "EquiServe Trust Company,
            N.A, a Massachusetts Trust Company".

      b.    The notice address for the Rights Agent in Section 26 of the
            Agreement shall be deleted in its entirety and replaced with
            "EquiServe Trust Company, N.A, a Massachusetts Trust Company, 150
            Royall Street, Canton, Massachusetts, 02021, Attention: Client
            Administration".

5.    Except as amended by this Agreement and Amendment, the Agreement and all
      schedules or exhibits thereto shall remain in full force and effect.

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IN WITNESS WHEREOF, the parties hereto have caused this Agreement and Amendment
to be executed in their names and on their behalf by and through their duly
authorized officers, as of this 31st day of May, 2002.

BIOGEN, INC.                            STATE STREET BANK AND TRUST COMPANY

/s/ Anne Marie Cook                     /s/ Charles Rossi
---------------------------             ------------------------------
Anne Marie Cook                         Charles Rossi
Vice President - Chief                  Division President
  Corporate Counsel

                                        EquiServe Trust Company, N.A.

                                        /s/ Carol Mulvey-Eri
                                        -----------------------------
                                        Carol Mulvey-Eri
                                        Managing Director