Filed by Immunex Corporation
                        Pursuant to Rule 425 under the Securities Act of 1933
                                     and deemed filed pursuant to Rule 14a-12
                                       of the Securities Exchange Act of 1934

                                       Subject Company: Immunex Corporation
                                              Commission File No. 333-81832

The following is a Press Release issued by Immunex Corporation in
connection with the acquisition of Immunex Corporation by Amgen Inc.
pursuant to an Amended and Restated Agreement and Plan of Merger (the
"Merger Agreement"), dated as of December 16, 2001, by and among Amgen
Inc., AMS Acquisition Inc. and Immunex Corporation. The Merger Agreement is
on file with the Securities Exchange Commission as an exhibit to the
definitive joint proxy statement/prospectus filed by Immunex and Amgen on
March 22, 2002, and is incorporated by reference into this filing.


FOR IMMEDIATE RELEASE               CONTACT: Josh Schroeter (media)
Monday, April 29, 2002                       206.389.4335
                                             John Calhoun (investors)
                                             206.389.4361


                  Immunex Announces Settlement Of Certain
               Litigations Relating To Merger With Amgen Inc.

SEATTLE, WA - Immunex Corporation (Nasdaq: IMNX) announced today the
settlement, which is subject to court approval among other things, of three
lawsuits against Immunex and certain of its directors and officers relating
to the proposed acquisition of Immunex by Amgen Inc.: (i) a suit filed by
David Osher, on behalf of a class of Immunex shareholders, against Immunex,
all members of the Immunex board of directors, Wyeth and Amgen; (ii) a suit
filed by Adele Brody, on behalf of a class of Immunex shareholders, against
Immunex, Wyeth, all members of the Immunex board of directors and the
marital community of each named individual; and (iii) a suit filed by Edwin
Weiner, on behalf of a class of Immunex shareholders, against Immunex,
against Immunex, Wyeth, all members of the Immunex board of directors and
the marital community of each named individual.

In connection with the settlement, (i) Immunex and Amgen agreed to reduce
the termination fee payable by Immunex or Amgen under certain circumstances
set forth in the Amended and Restated Agreement and Plan of Merger among
Immunex, Amgen and a wholly-owned subsidiary of Amgen by $20 million, (ii)
Immunex obtained an updated opinion from Merrill Lynch, Pierce, Fenner &
Smith Incorporated regarding the fairness of the merger consideration from
a financial point of view to be received by Immunex shareholders, and (iii)
Immunex agreed to provide certain additional disclosures regarding the
merger in a Current Report on Form 8-K, which is being filed with the
Securities and Exchange Commission today.

On December 17, 2001, Immunex agreed to be acquired by Amgen. The
acquisition will merge Immunex, one of the fastest growing biotechnology
companies in the industry, with Amgen, the largest biotechnology company.
Pending required shareholder approval for both companies, and approval by
regulatory authorities, the transaction is expected to be completed as
early as June 2002. Shareholder meetings for both companies are scheduled
to occur on May 16, 2002.

Immunex Corporation is a leading biopharmaceutical company dedicated to
improving lives through immune system science innovations.

Note: Except for the historical information contained herein, this news
release contains forward-looking statements that involve substantial risks
and uncertainties. Among the factors that could cause actual results or
timelines to differ materially are risks associated with research and
clinical development, regulatory approvals, our supply capabilities and
reliance on third-party manufacturers, product commercialization,
competition, litigation and other risk factors listed from time to time in
reports filed by Immunex with the Securities and Exchange Commission,
including but not limited to risks described under the caption "Important
Factors That May Affect Our Business, Our Results of Operation and Our
Stock Price" within our most recently filed Form 10-K. The forward-looking
statements contained in this news release represent our judgment as of the
date of this release. Immunex undertakes no obligation to publicly update
any forward-looking statements. An electronic version of this news
release-as well as additional information about Immunex of interest to
investors, customer, future employees and patients-is available on the
Immunex home page at www.immunex.com.

Where You can find Additional Information about the Merger
In connection with the proposed acquisition, Immunex and Amgen filed with
the SEC on March 22, 2002 a definitive joint proxy statement/prospectus
that contains important information about the merger. Investors and
security holders of Immunex and Amgen are urged to read the definitive
joint proxy statement/prospectus filed with the SEC on March 22, 2002 and
any other relevant materials filed by Immunex or Amgen because they
contain, or will contain, important information about Immunex, Amgen and
the acquisition. The definitive joint proxy statement/prospectus filed with
the SEC on March 22, 2002, other relevant materials and any other documents
filed, or to be filed, by Immunex or Amgen with the SEC, may be obtained
free of charge at the SEC's Web site at www.sec.gov. In addition, investors
and security holders may obtain free copies of the documents filed with the
SEC by Immunex by contacting Immunex Corporation, 51 University Street,
Seattle, WA 98101, Attn: Investor Relations. Investors and security holders
may obtain free copies of the documents filed with the SEC by Amgen by
directing a request to Amgen Inc., One Amgen Center Drive, Thousand Oaks,
CA 91320, Attn: Investor Relations. Investors and security holders are
urged to read the definitive joint proxy statement/prospectus filed with
the SEC on March 22, 2002 and any other relevant materials filed by Immunex
or Amgen before making any voting or investment decision with respect to
the Acquisition.

Immunex, Amgen and their respective executive officers and directors may be
deemed to be participants in the solicitation of proxies from the
stockholders of Immunex and Amgen in favor of the merger. Information about
the executive officers and directors of Immunex and their ownership of
Immunex common stock, and information about the executive officers and
directors of Amgen and their ownership of Amgen common stock is set forth
in the joint proxy statement/prospectus for Immunex's special meeting of
stockholders in to be held in connection with the merger and Amgen's
special meeting of stockholders to be held in connection with the merger,
which has been filed with the SEC. Investors and security holders may
obtain more detailed information regarding the direct and indirect
interests of Immunex, Amgen and their respective executive officers and
directors in the merger by reading the joint proxy/statement prospectus
regarding the acquisition.