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                                                                    Exhibit 10.7

                                 AMENDMENT NO. 1
                           TO THE AMENDED AND RESTATED
                              GOVERNANCE AGREEMENT

     This Amendment No. 1 ("Amendment No. 1") is made this 20th day of May, 1999
(the "Amendment Effective Date") by and between AMERICAN CYANAMID COMPANY, a
corporation organized and existing under the laws of the State of Maine
("CYANAMID") and a wholly-owned subsidiary of AMERICAN HOME PRODUCTS
CORPORATION, a corporation organized and existing under the laws of the State of
Delaware and having its principal office at Five Giralda Farms, Madison, New
Jersey 07940 ("AHPC") and IMMUNEX CORPORATION, a corporation organized and
existing under the laws of the State of Washington and having its principal
office at 51 University Street, Seattle, Washington 98101 ("IMMUNEX"), and
amends the Amended and Restated Governance Agreement dated as of December 15,
1992, among American Cyanamid Company, Immunex Corporation and Lederle Oncology
Corporation (the "Governance Agreement").

     WHEREAS, AHPC and IMMUNEX have entered into a certain Note Purchase
Agreement dated as of the date hereof, pursuant to which IMMUNEX has issued, and
AHPC has purchased, a 3% Convertible Subordinated Note due 2006 in the principal
amount of $450 million ("Note"), which Note is convertible, in whole or in part,
into common stock of IMMUNEX at a specified price per share, subject to
adjustment in certain circumstances;

     WHEREAS, AHPC and IMMUNEX have agreed that the shares that are subject to
issuance to AHPC upon conversion of the Note may be included in the calculation
of AHPC's and CYANAMID's ownership of Immunex common stock for certain purposes
under the Governance Agreement;

     NOW THEREFORE, in consideration of the mutual covenants contained herein,
and for other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties hereto, each intending to be legally
bound, hereby agree as follows:

     1.   All initially capitalized terms used herein and not defined shall have
          the meanings set forth in the Governance Agreement.

     2.   Article II of the Governance Agreement shall be amended to add the
          following new provision, Section 2.03, as follows:

     2.03 COMMON STOCK ISSUABLE UPON CONVERSION OF NOTE. The Common Stock
          issuable upon conversion of the Note issued by the Company and
          purchased by American Home Products Corporation ("AHPC") pursuant to
          the Note Purchase Agreement dated as of May 20, 1999 shall, at the
          option of Cyanamid, regardless of whether the Note is converted by
          AHPC so long as AHPC or its Affiliates hold the Note, be included in
          (i) "Cyanamid's Interest" for purposes of Article IV; (ii) Cyanamid's
          "Pro Rata Share" for purposes of Section 2.01; (iii) Cyanamid's "Owned
          Shares" for purposes of Section 2.02 (and shall be deemed to be issued
          and outstanding as of the Quarterly Date immediately preceding the
          effective date of the Note Purchase Agreement) ; and (iv) "Registrable
          Securities" for purposes of Article VI.

     3.   Article V of the Governance Agreement shall be amended to add the
          following new provision, Section 5.01(h), as follows:

          (h) The Note issued by the Company and purchased by AHPC pursuant to
          the Note Purchase Agreement dated as of May 20, 1999 shall not be
          deemed to be an interest in New Shares for purposes of Section 5.01(c)
          hereof and AHPC shall have the right to transfer such Note in
          accordance with the terms of the Note Purchase Agreement.
          Notwithstanding the foregoing, however, the Common Stock issuable upon
          conversion of such Note shall, when and if issued, be deemed to be New
          Shares for purposes of this Article V.


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     4.   The first clause of Section 6.03(d) shall be deleted in its entirety
          and replaced as follows:

          (d)   The Company shall not be obligated to effect more than three
                registrations pursuant to this Section 6.03;

     5.   Except as otherwise set forth in this Amendment No. 1, all other
          terms and provisions of the Governance Agreement shall remain in full
          force and effect.

     6.   This Amendment No. 1 may be executed in counterparts, each of which
          shall be deemed an original and all of which shall constitute together
          one and the same instrument.


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IN WITNESS WHEREOF, the parties hereto have executed this Amendment No. 1 as of
the day and year first above written.


IMMUNEX CORPORATION                           AMERICAN HOME PRODUCTS CORPORATION

By: /s/ Edward V. Fritzky                     By: /s/ Gerald A. Jibilian

Name: Edward V. Fritzky                       Name: Gerald A Jibilian
Title: Chairman and Chief Executive Officer   Title: Vice President


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