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                                                                     Exhibit 3.1

                       RESTATED ARTICLES OF INCORPORATION
                                       OF
                               IMMUNEX CORPORATION

Pursuant to RCW 23B.10.070, the following constitutes Restated Articles of
Incorporation of the undersigned, a Washington corporation.

                                 ARTICLE 1. NAME
              The name of this corporation is Immunex Corporation.

                                ARTICLE 2. SHARES

2.1  Authorized Capital
The total number of shares which the corporation is authorized to issue is
1,230,000,000, consisting of 1,200,000,000 shares of Common Stock having a par
value of $.01 per share and 30,000,000 shares of Preferred Stock having a par
value of $.01 per share. The Common Stock is subject to the rights and
preferences of the Preferred Stock as hereinafter set forth.

2.2  Issuance of Preferred Stock in Series
The Preferred Stock may be issued from time to time in one or more series in any
manner permitted by law and the provisions of these Articles of Incorporation of
the corporation, as determined from time to time by the Board of Directors and
stated in the resolution or resolutions providing for the issuance thereof,
prior to the issuance of any shares thereof. The Board of Directors shall have
the authority to fix and determine and to amend, subject to the provisions
hereof, the designation, preferences, limitations and relative rights of the
shares of any series that is wholly unissued or to be established. Unless
otherwise specifically provided in the resolution establishing any series, the
Board of Directors shall further have the authority, after the issuance of
shares of a series whose number it has designated, to amend the resolution
establishing such series to decrease the number of shares of that series, but
not below the number of shares of such series then outstanding.

2.3  Dividends
The holders of shares of the Preferred Stock shall be entitled to receive
dividends, out of the funds of the corporation legally available therefor, at
the rate and at the time or times, whether cumulative or noncumulative, as may
be provided by the Board of Directors in designating a particular series of
Preferred Stock. If such dividends on the Preferred Stock shall be cumulative,
then if dividends shall not have been paid, the deficiency shall be fully paid
or the dividends declared and set apart for payment at such rate, but without
interest on cumulative dividends, before any dividends on the Common Stock shall
be paid or declared and set apart for payment. The holders of the Preferred
Stock shall not be entitled to receive any dividends thereon other than the
dividends referred to in this section.

2.4  Redemption
The Preferred Stock may be redeemable at such price, in such amount, and at such
time or times as may be provided by the Board of Directors in designating a
particular series of Preferred Stock. In any event, such Preferred Stock may be
repurchased by the corporation to the extent legally permissible.

2.5  Liquidation
In the event of any liquidation, dissolution, or winding up of the affairs of
the corporation, whether voluntary or involuntary, then, before any distribution
shall be made to the holders of the Common Stock, the holders of the Preferred
Stock at the time outstanding shall be entitled to be paid the preferential
amount or amounts per share as may be provided by the Board of Directors in
designating a particular series of Preferred Stock and dividends accrued thereon
to the date of such payment. The holders of the Preferred Stock shall not be
entitled to receive any distributive amounts upon the liquidation, dissolution,
or winding up of the affairs of the corporation other than the distributive
amounts referred to in this section, unless otherwise provided by the Board of
Directors in designating a particular series of Preferred Stock.


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2.6  Conversion
Shares of Preferred Stock may be convertible into Common Stock of the
corporation upon such terms and conditions, at such rate and subject to such
adjustments as may be provided by the Board of Directors in designating a
particular series of Preferred Stock.

2.7  Voting Rights
Holders of Preferred Stock shall have such voting rights as may be provided by
the Board of Directors in designating a particular series of Preferred Stock.

                     ARTICLE 3. REGISTERED OFFICE AND AGENT
The name of the initial registered agent of this corporation and the address of
its initial registered office are as follows:

                    Scott G. Hallquist
                    51 University Street
                    Seattle, WA 98101

                          ARTICLE 4. PREEMPTIVE RIGHTS
No preemptive rights shall exist with respect to shares of stock or securities
convertible into shares of stock of this corporation.

                          ARTICLE 5. CUMULATIVE VOTING
The right to cumulate votes in the election of Directors shall not exist with
respect to shares of stock of this corporation.

                              ARTICLE 6. DIRECTORS
6.1  Number and Term of Directors
The number of Directors of this corporation shall be determined in the manner
provided by the Bylaws and may be increased or decreased from time to time in
the manner provided therein, PROVIDED, HOWEVER, that the number of directors
shall not be reduced so as to shorten the term of any director at the time in
office. Directors need not be shareholders. Unless a director dies, resigns, or
is removed, he shall hold office until the next annual meeting of shareholders
or until his successor is elected and qualified, whichever is later.

6.2  Removal of Directors
Subject to the terms of the Amended and Restated Governance Agreement, dated as
of December 15, 1992, among Immunex Corporation, Lederle Oncology Corporation
and American Cyanamid Company ("Cyanamid"), as it may be amended or restated
from time to time (the "Governance Agreement"), one or more members of the Board
of Directors (including the entire Board) may be removed, with or without cause,
by the written consent of the holders of record of a majority of the outstanding
shares of stock entitled to vote generally in the election of directors, voting
together as a single class (the "Voting Stock").

6.3  Vacancies
Any vacancy occurring on the Board of Directors may be filled, subject to the
terms of the Governance Agreement, by the affirmative vote of a majority of the
remaining directors, though less than a quorum. A director elected to fill a
vacancy shall be elected for the unexpired term of his or her predecessor in
office. Any directorship to be filled by reason of an increase in the number of
directors may be filled by the Board, subject to the Governance Agreement, for a
term of office continuing only until the next election of directors by the
shareholders.

                                ARTICLE 7. BYLAWS
All of the powers of this corporation, insofar as the same may be lawfully
vested by these Articles of Incorporation in the Board of Directors, are hereby
conferred upon the Board of Directors of this corporation. In furtherance and
not in limitation of that power, the Board of Directors, subject to the
Governance Agreement, shall have the power to adopt, amend or repeal the Bylaws
of this corporation, subject to the power of the shareholders to amend or repeal
such Bylaws. The shareholders shall also have the power to amend or repeal the
Bylaws of this corporation and to adopt new Bylaws. No action may be taken or
effected by written consent of shareholders in lieu of a meeting.


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                     ARTICLE 8. SPECIAL SHAREHOLDER MEETINGS
Special meetings of the shareholders of the corporation for any purpose or
purposes may be called at any time by the Board of Directors, the Chairman of
the Board of Directors, or the President of the corporation. Further, a special
meeting of the shareholders shall be held if the holders of not less than 40% of
all the votes entitled to be cast on any

issue proposed to be considered at such special meeting have dated, signed and
delivered to the Secretary one or more written demands for such meeting,
describing the purpose or purposes for which it is to be held.

           ARTICLE 9. MERGERS, SHARE EXCHANGES, AND OTHER TRANSACTIONS
Subject to the Governance Agreement, a merger, share exchange, sale of
substantially all of the corporation's assets, or dissolution must be approved
by the affirmative vote of a majority of the corporation's outstanding shares
entitled to vote, or if separate voting by voting groups is required then by not
less than a majority of all the votes entitled to be cast by that voting group.

               ARTICLE 10. AMENDMENTS TO ARTICLES OF INCORPORATION
Subject to the Governance Agreement and except as otherwise provided herein,
this corporation reserves the right to amend or repeal by the affirmative vote
of the holders of a majority of the outstanding Voting Stock, any of the
provisions contained in these Articles of Incorporation in any manner now or
hereafter permitted by law, and the rights of the shareholders of this
corporation are granted subject to this reservation.

                  ARTICLE 11. LIMITATION OF DIRECTOR LIABILITY
To the full extent that the Washington Business Corporation Act (the "Act"), as
it exists on the date hereof or may hereafter be amended, permits the limitation
or elimination of the liability of Directors, a Director of this corporation
shall not be liable to this corporation or its shareholders for monetary damages
for conduct as a Director. Any amendments to or repeal of this Article 11 shall
not adversely affect any right or protection of a Director of this corporation
for or with respect to any acts or omissions of such Director occurring prior to
such amendment or repeal. Notwithstanding any other provisions of law, these
Articles of Incorporation (except as hereinafter provided) or the Bylaws of this
corporation, the affirmative vote of the holders of not less than 80% of the
Voting Stock shall be required to alter, amend or repeal, or to adopt any
provisions inconsistent with, this Article 11 or any provision hereof.

              ARTICLE 12. INDEMNIFICATION OF DIRECTORS AND OFFICERS
This corporation shall indemnify its Directors and Officers to the full extent
not prohibited by applicable law now or hereafter in force against liability
arising out of a proceeding to which such individual was made a party because
the individual is or was a Director or an Officer. However, such indemnity shall
not apply on account of:

     (a)  acts or omissions of a Director or Officer finally adjudged to be
          intentional misconduct or a knowing violation of law;

     (b)  conduct of a Director or Officer finally adjudged to be in violation
          of Section 23B.08.310 of the Act relating to distributions by this
          corporation; or

     (c)  any transaction with respect to which it was finally adjudged that
          such Director or Officer personally received a benefit in money,
          property, or services to which the Director or Officer was not legally
          entitled.

Subject to the foregoing, it is specifically intended that proceedings covered
by indemnification shall include proceedings brought by this corporation
(including derivative actions), proceedings by government entities and
governmental officials or other third party actions.

                   ARTICLE 13. RESOLUTION OF CONFLICTING TERMS
Notwithstanding any other provision of these Articles of Incorporation, any
conflict between (a) any action taken by this corporation or the Board of
Directors, or any provision of these Articles of Incorporation or the Bylaws of
this


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corporation, as each may be amended and/or restated from time to time, on the
one hand, and (b) the terms of the Governance Agreement on the other, shall be
resolved in favor of the terms of the Governance Agreement unless otherwise
agreed to in writing by Cyanamid. Any amendment or repeal of this Article 13
shall require the affirmative vote of the holders of more than 70% of the Common
Stock on a fully diluted basis.

                ARTICLE 14. ELECTION TO NOT BE COVERED BY STATUTE
This corporation elects not to be covered by the provisions of Section
23B.17.020 of the Act.

                            ARTICLE 15. INCORPORATOR
The name and address of the incorporator are as follows:
                         Stephen M. Graham
                         1201 Third Avenue, 40th Floor
                         Seattle, Washington 98101-3099

Dated:  February 18, 2000.

                         IMMUNEX CORPORATION

                         /s/ Barry G. Pea
                         ---------------------------------------------
                         NAME: BARRY G. PEA
                         TITLE: VICE PRESIDENT, DEPUTY GENERAL
                                COUNSEL AND ASSISTANT SECRETARY


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