EXHIBIT 10.4

                               IMMUNEX CORPORATION
                   STOCK OPTION PLAN FOR NONEMPLOYEE DIRECTORS
                     Amended and Restated on April 18, 2000

SECTION 1.  PURPOSES

     The purposes of the Immunex Corporation Stock Option Plan for Nonemployee
Directors (this "Plan") are to attract and retain the services of experienced
and knowledgeable nonemployee directors of Immunex Corporation (the "Company")
and to provide an incentive for such directors by providing an opportunity for
stock ownership in the Company.

SECTION 2.  SHARES SUBJECT TO THE PLAN

     Subject to adjustment in accordance with Section 6 hereof, the total number
of shares of the Company's common stock (the "Common Stock") for which options
may be granted under this Plan is 1,200,000/1/ (the "Shares"). The Shares shall
be shares currently authorized but unissued or subsequently acquired by the
Company and shall include shares representing the unexercised portion of any
option granted under this Plan which expires or terminates without being
exercised in full.

SECTION 3.  ADMINISTRATION OF THE PLAN

     The administrator of this Plan (the "Plan Administrator") shall be the
Board of Directors of the Company (the "Board"). Subject to the terms of this
Plan, the Plan Administrator shall have the power to construe the provisions of
this Plan, to determine all questions arising hereunder and to adopt and amend
such rules and regulations for the administration of this Plan as it may deem
desirable.

SECTION 4.  PARTICIPATION IN THE PLAN

     4.1    Eligible Directors

     Each member of the Board elected or appointed who is not otherwise an
employee of the Company, any parent or subsidiary corporation, or a director
appointed by American Cyanamid Company or American Home Products Corporation
pursuant to the Amended and Restated Governance Agreement dated as of December
15, 1992 (an "Eligible Director") shall be eligible to participate in this Plan.

____________
     /1/ The original number of Shares in this Plan was 100,000. This number was
adjusted to 1,200,000 as a result of a 2-for-1 stock split on March 25, 1999, a
2-for-1 stock split on August 26, 1999 and a 3-for-1 stock split on March 20,
2000.

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     4.2   Initial Grants

     Each Eligible Director who is elected or appointed for the first time after
the date of adoption of this Plan shall automatically receive the grant of an
option to purchase 10,000 Shares on the day such Eligible Director is initially
elected or appointed.

     4.3   Annual Grants

     Each Eligible Director continuing service as an Eligible Director
immediately following an Annual Meeting of Shareholders shall automatically
receive an option to purchase 5,000 Shares immediately following each year's
Annual Meeting of Shareholders as an annual grant; provided, however, that an
Eligible Director who has received an initial grant of an option to purchase
10,000 Shares on such date shall not receive an annual grant until the next
Annual Meeting.

SECTION 5. OPTION TERMS

     Each option granted to an Eligible Director under this Plan and the
issuance of Shares hereunder shall be subject to the following terms:

     5.1   Option Agreement

     Each option granted under this Plan shall be evidenced by an option
agreement (an "Agreement") duly executed on behalf of the Company. Each
Agreement shall comply with and be subject to the terms and conditions of this
Plan. Any Agreement may contain such other terms, provisions and conditions not
inconsistent with this Plan as may be determined by the Plan Administrator.

     5.2   Option Exercise Price

     The option exercise price for an option granted under this Plan shall be
the closing price, or if there is no closing price, the mean between the high
and the low sale price of the Shares covered by the option on the day the option
is granted on the Nasdaq Stock Market or, if no Common Stock was traded on such
date, on the immediately preceding date on which Common Stock was so traded.

     5.3   Vesting and Exercisability

     Each option granted to an Eligible Director shall vest and become
exercisable in accordance with the following schedule:

 Period of Eligible Directors' Continuous
Service as a Director With the Company From     Portion of Total Option Which Is
   the Date the Option is Granted                         Exercisable
- ---------------------------------------------  ---------------------------------

      Less than twelve months                                 0%

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            Twelve months                              20%

          Twenty-four months                           40%

          Thirty-six months                            60%

          Forty-eight months                           80%

       Sixty months or greater                        100%

     Notwithstanding the foregoing, for any Option granted under the Plan, the
Option shall become 100% vested and exercisable on the date of termination of an
Eligible Director's service as a member of the Board on account of the Eligible
Director's death, provided that the Eligible Director has served as a member of
the Board for at least two years at the date of such Eligible Director's death.

     5.4 Time and Manner of Exercise of Option

     Each option may be exercised in whole or in part at any time and from time
to time; provided, however, that no fewer than 100 Shares (or the remaining
Shares then purchasable under the option, if less than 100 Shares) may be
purchased upon any exercise of any option hereunder and that only whole Shares
will be issued pursuant to the exercise of any option.

     Any option may be exercised by giving written notice, signed by the person
exercising the option, to the Company stating the number of Shares with respect
to which the option is being exercised, accompanied by payment in full for such
Shares, which payment may be in whole or in part (a) in cash or by check, (b) in
shares of Common Stock already owned for at least six months by the person
exercising the option, valued at fair market value at the time of such exercise,
or (c) by delivery of a properly executed exercise notice, together with
irrevocable instructions to a broker, to properly deliver to the Company the
amount of sale or loan proceeds to pay the exercise price, all in accordance
with the regulations of the Federal Reserve Board.

     5.5 Term of Options

    Each option shall expire ten years from the date of the granting thereof,
but shall be subject to earlier termination as follows:

          (a)   In the event that an optionee ceases to be a director of the
     Company for any reason other than the death of the optionee the unvested
     portion of the options granted to such optionee shall terminate immediately
     and the vested portion of the options granted to such optionee may be
     exercised by him or her only within three months after the date such
     optionee ceases to be a director of the Company.

          (b)   In the event of the death of an optionee, whether during the
     optionee's service as a director or during the three month period referred
     to in Section 5.5(a), the unvested portion of the options granted to such
     optionee shall terminate immediately and the vested portion of the options
     granted to such optionee shall be exercisable, and such

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     options shall expire unless exercised within twelve months after the date
     of the optionee's death, by the legal representatives or the estate of such
     optionee, by any person or persons whom the optionee shall have designated
     in writing on forms prescribed by and filed with the Company or, if no such
     designation has been made, by the person or persons to whom the optionee's
     rights have passed by will or the laws of descent and distribution.

     5.6  Transferability

     During an optionee's lifetime, an option may be exercised only by the
optionee. Options granted under this Plan and the rights and privileges
conferred thereby shall not be subject to execution, attachment or similar
process and may not be transferred, assigned, pledged or hypothecated in any
manner (whether by operation of law or otherwise) other than by will or by the
applicable laws of descent and distribution. In addition, the Plan Administrator
may permit a recipient of an option to designate in writing during the
optionee's lifetime a beneficiary to receive and exercise options in the event
of the optionee's death (as provided in Section 5.5(b)). Any attempt to
transfer, assign, pledge, hypothecate or otherwise dispose of any option under
this Plan or of any right or privilege conferred thereby, contrary to the
provisions of this Plan, or the sale or levy or any attachment or similar
process upon the rights and privileges conferred hereby, shall be null and void.

     5.7  Holding Period

     If an individual subject to Section 16 of the Exchange Act of 1934, as
amended (the "Exchange Act") sells shares of Common Stock obtained upon the
exercise of any option granted under this Plan within six months after the date
the option was granted, such sale may result in short-swing profit recovery
under Section 16(b) of the Exchange Act.

     5.8  Participant's or Successor's Rights as Shareholder

     Neither an optionee nor the optionee's successor(s) in interest shall have
any rights as a shareholder of the Company with respect to any Shares subject to
an option granted to the optionee until such person becomes a holder of record
of such Shares.

     5.9  Limitation as to Directorship

     Neither this Plan, nor the granting of an option, nor any other action
taken pursuant to this Plan shall constitute or be evidence of any agreement or
understanding, express or implied, that an optionee has a right to continue as a
director for any period of time or at any particular rate of compensation.

     5.10 Regulatory Approval and Compliance

     The Company shall not be required to issue any certificate or certificates
for Shares upon the exercise of an option granted under this Plan, or record as
a holder of record of Shares the name of the individual exercising an option
under this Plan, without obtaining to the complete satisfaction of the Plan
Administrator the approval of all regulatory bodies deemed necessary by

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the Plan Administrator, and without complying, to the Plan Administrator's
complete satisfaction, with all rules and regulations under federal, state or
local law deemed applicable by the Plan Administrator.

SECTION 6. CAPITAL ADJUSTMENTS

     The aggregate number and class of Shares for which options may be granted
under this Plan, the number and class of Shares covered by each outstanding
option and the exercise price per Share thereof (but not the total price) shall
all be proportionately adjusted for any stock dividends, stock splits,
recapitalizations, combinations or exchanges of shares, split-ups, split-offs,
spinoffs, or other similar changes in capitalization. Notwithstanding the
foregoing, if an automatic grant occurs within ninety days following any such
change in capitalization, the aggregate number and class of Shares subject to
such automatic grant shall be proportionately adjusted to be the same number and
class of Shares that would be subject to the automatic grant had it been
outstanding immediately prior to the date of such change in capitalization. Upon
the effective date of a dissolution or liquidation of the Company, or of a
reorganization, merger or consolidation of the Company with one or more
corporations that results in more than 70% of the outstanding voting shares of
the Company being owned by one or more affiliated corporations or other
affiliated entities, or of a transfer of all or substantially all the assets or
more than 70% of the then outstanding shares of the Company to another
corporation or other entity, this Plan and all options granted hereunder shall
terminate. In the event of such dissolution, liquidation, reorganization,
merger, consolidation, transfer of assets or transfer of stock, each optionee
shall be entitled, for a period of twenty days prior to the effective date of
such transaction, to purchase the full number of shares under his or her option
which he or she otherwise would have been entitled to purchase during the
remaining term of such option.

     Adjustments under this Section 6 shall be made by the Plan Administrator,
whose determination shall be final. In the event of any adjustment in the number
of Shares covered by any option, any fractional Shares resulting from such
adjustment shall be disregarded and each such option shall cover only the number
of full Shares resulting from such adjustment.

SECTION 7. EXPENSES OF THE PLAN

     All costs and expenses of the adoption and administration of this Plan
shall be borne by the Company; none of such expenses shall be charged to any
optionee.

SECTION 8. COMPLIANCE WITH RULE 16b-3

     It is the intention of the Company that this Plan comply in all respects
with the requirements for a "formula plan" within the meaning attributed to that
term for purposes of Rule 16b-3 promulgated under Section 16(b) of the Exchange
Act. Therefore, if any Plan provision is later found not to be in compliance
with such requirements, that provision shall be deemed null and void, and in all
events this Plan shall be construed in favor of its meeting such requirements.

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SECTION 9.   TERMINATION AND AMENDMENT OF THE PLAN

     The Board may amend, terminate or suspend this Plan at any time, in its
sole and absolute discretion; provided, however, that if required to qualify
this Plan as a formula plan for purposes of Rule 16b-3 under Section 16(b) of
the Exchange Act, no amendment may be made more than once every six months that
would change the amount, price, timing or vesting of the options, other than to
comply with changes in the Internal Revenue Code of 1986, as amended, or the
rules and regulations thereunder; provided further that no amendment that would
(a) increase the number of Shares that may be issued under this Plan, or (b)
otherwise require shareholder approval under any applicable law or regulation
shall be made without the approval of the Company's shareholders.

SECTION 10.  DURATION

     This Plan shall continue in effect until December 13, 2003 unless it is
sooner terminated by action of the Board or the Company's shareholders, but such
termination shall not affect the terms of any then-outstanding options. Adopted
by the Company's Board of Directors on December 13, 1993 and approved by the
Company's shareholders on April 27, 1994. Amended and restated by the Board on
February 13, 1997. Amended and restated by the Board on February 23, 1999.
Amended and restated by the Board on April 18, 2000.

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                                    ADDENDUM
                                     TO THE
                               IMMUNEX CORPORATION
                   STOCK OPTION PLAN FOR NONEMPLOYEE DIRECTORS

     WHEREAS, Immunex Corporation (the "Company") maintains the Stock Option
Plan for Nonemployee Directors (the "Plan"); and

     WHEREAS, the Company desires to adjoin an addendum (this "Addendum") to the
Plan to address the effects of the transactions contemplated by the Agreement
and Plan of Merger by and between Amgen Inc., AMS Acquisition Inc. and the
Company dated as of December 16, 2001 (the "Merger Agreement");

     NOW, THEREFORE, notwithstanding anything in the Plan to the contrary, this
Addendum is hereby adopted, effective as of the Effective Time (as defined in
the Merger Agreement):

     Section 1. At the Effective Time, each option granted pursuant the Plan
shall be treated in accordance with the applicable terms of the Merger
Agreement.

     Section 2. In the event that an optionee ceases to be a director of the
Company or Amgen Inc. for any reason immediately prior to, at, or during the
fifteen (15) months following the Effective Time, each option held by such
optionee for common stock of Amgen Inc. shall immediately vest in full and shall
remain exercisable until the earlier of (x) the first anniversary of the date
such optionee ceases to be a director of the Company or Amgen Inc. or (y) the
end of the term of such option.

     Section 3. This Addendum shall be effective only upon the Effective Time.
In the event that the Merger Agreement terminates according to its terms, this
Addendum shall be of no force or effect.