IMMUNEX CORP /DE/
AMENDMENT NO. 1 TO THE ENBREL SUPPLY AGREEMENT
<DOCUMENT>
<TYPE>EX-10.1
<SEQUENCE>2
<FILENAME>0002.txt
<DESCRIPTION>AMENDMENT NO. 1 TO THE ENBREL SUPPLY AGREEMENT
<TEXT>

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                                                                    Exhibit 10.1

                            AMENDMENT NO. 1 TO THE
                          ENBREL(R) SUPPLY AGREEMENT


[*] Certain information in this Exhibit has been omitted and filed separately
with the Securities and Exchange Commission pursuant to a confidential treatment
request.

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                            AMENDMENT NO. 1 TO THE

                          ENBREL(R) SUPPLY AGREEMENT

     This Amendment No. 1 ("Amendment No. 1") is made this 27th day of June,
2000 (the "Amendment Effective Date") by and among IMMUNEX CORPORATION, a
corporation of the State of Washington, having its principal place of business
at 51 University Street, Seattle, Washington 98101, U.S.A., together with its
Affiliates ("Immunex"), AMERICAN HOME PRODUCTS CORPORATION, a corporation of the
State of Delaware having its corporate headquarters at Five Giralda Farms,
Madison, New Jersey 07940, U.S.A. ("AHPC"), acting through its Wyeth-Ayerst
Laboratories division, having offices at 555 East Lancaster Avenue, St. Davids,
Pennsylvania 19087, U.S.A. ("Wyeth"), and BOEHRINGER INGELHEIM PHARMA KG, a
German corporation having a place of business at Birkendorfer Strasse 65, 88397
Biberach an der Riss, Federal Republic of Germany ("BIP"), and amends the Enbrel
Supply Agreement effective as of November 5, 1998, by and among Immunex, Wyeth,
and BIP (the "Agreement").

     WHEREAS, Immunex, Wyeth and BIP have entered into a certain Agreement for
BIP's supply of Enbrel(R) (etanercept) to Immunex and Wyeth;

     WHEREAS, Immunex and Wyeth desire to have BIP manufacture additional
quantities of Enbrel, and accordingly, on January 20, 2000, the Parties signed a
certain Summary Term Sheet specifying terms and conditions under which BIP would
receive certain incentives to enhance the yield from BIP's current production
capacity for Enbrel and to perform good faith outsourcing activities with the
goal of providing additional near-term bulk drug substance runs for Enbrel;

     WHEREAS, pursuant to Section 23.9 of the Agreement, the Agreement may only
be amended and supplemented by a written instrument signed by the Parties;

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

     2.   New Definitions. Section 1.66 of the Agreement shall be amended to add
the following new definitions:
                                                             Section
     "Accepted Subsequent Additional Runs"                   24.1(d)(2)
     "Adjusted Annual Minimum"                               5.10(c)
     "Annual Minimum"                                        5.10(b)
     "Attempted Original Additional Run"                     24.1(a)(2)
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     "Binding Production Schedule"                            24.1(a)(1)(i)
     "Confirmed Outsourcing Costs"                            24.1(a)
     "Outsourcing Activities"                                 24.1(a)
     "Original Additional Run"                                24.1(a)(1)
     "ROFR"                                                   24.1(d)(2)
     "Subsequent Additional Runs"                             24.1(c)(3)
     "Successful Outsourcing Activities"                      24.3
     "Unsuccessful Outsourcing Activities"                    24.2

     3.   Semi-Exclusive Rights. In consideration of the mutual covenants set
forth in this Amendment No. 1, a new Section 3.4 shall be added to the Agreement
as follows:

          3.4 Semi-Exclusive Rights. Subject to Section 5.10(c) hereof, BIP's
rights to manufacture Bulk Drug Substance and Drug Product for Immunex and Wyeth
hereunder shall be converted from exclusive (subject to the provisions of
Section 3.2 and 3.3 hereof) to semi-exclusive with Immunex and Wyeth. Thus, in
addition to the Firm Orders for Bulk Drug Substance and Drug Product placed by
the Buyer with BIP in accordance with the terms of this Agreement, Immunex and
Wyeth shall also have the right to (a) manufacture any quantities of Bulk Drug
Substance in Wyeth's West Greenwich, Rhode Island manufacturing facility or in
such other manufacturing facility, including but not limited to, Wyeth's
proposed manufacturing facility in Ireland, that is at least [*] percent ([*]%)
owned by Immunex or Wyeth or by an Affiliate of either Immunex or Wyeth and (b)
determine where the Bulk Drug Substance produced from any such Immunex or Wyeth-
owned manufacturing facility would be converted into drug product (unlabeled
vials), it being understood that any facility converting such Bulk Drug
Substance to drug product for Immunex or Wyeth could be owned by Immunex, Wyeth,
by an Affiliate of either Immunex or Wyeth, or by a Third Party.

     4.   Maximum Request and Annual Minimum. In consideration of BIP's consent
to convert its exclusive manufacturing rights to semi-exclusive manufacturing
rights described in Paragraph 3 of this Amendment No. 1 and BIP's good faith
outsourcing efforts, the Agreement shall be amended to add the following new
Section 5.10, as follows:

          5.10   Maximum Request; Annual Minimum.

                 (a)   Maximum Request. Subject to Section 5.10(c) below,
                       beginning on [*] and continuing through [*], the annual
                       Maximum Request in the Agreement shall be equal to the
                       Annual Minimum as defined in Section 5.10(b) below.
                       Beginning [*], or as otherwise set forth in Section
                       5.10(c) below, the Maximum Request shall revert to the
                       terms in the original Agreement. Immunex and Wyeth shall
                       waive their ability to reduce the Maximum Request below
                       the Annual Minimum under Section 5.1(b) hereof until an
                       effective date of [*] at the earliest, except to the
                       extent otherwise permitted in Section 5.10(c) below.
                       Subject to Section 5.10(c) below, beginning on [*] and
                       continuing through the

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                       end of the Supply Term, Immunex and Wyeth shall be
                       entitled to reduce the Maximum Request (unless otherwise
                       agreed in writing among the Parties, to be calculated by
                       using the original Maximum Request herein) by no more
                       than [*] percent ([*]%) per Calendar Year by providing at
                       least the required [*] ([*]) months' prior written notice
                       to BIP (e.g., notice by [*] for a potential reduction in
                       the Maximum Request effective as of [*], etc.).

                       It is understood by the Parties that the Maximum Request
                       valid through [*] shall not constitute a guaranty by BIP
                       to reserve permanent capacity through [*] exceeding the
                       original Maximum Request of [*] Bulk Drug Substance Runs.
                       However, to carry out the Parties' intentions, to the
                       extent that BIP acquires any Original Additional Run or
                       Subsequent Additional Run as a result of its Outsourcing
                       Activities, (1) all such Original Additional Runs shall
                       be reserved for Buyer through [*] and (2) Buyer shall
                       have a ROFR for any Subsequent Additional Run during
                       Calendar Years [*] and [*], and such ROFR shall be
                       exercised according to Section 24.1(d)(2) hereof.
                       Moreover, the absolute minimum of the Maximum Request
                       after permitted reductions under Section 5.1(b) of the
                       original Agreement shall always be the required capacity
                       for [*] kg of Bulk Drug Substance calculated in
                       accordance with the original Production Assumptions
                       herein.

                 (b)   Annual Minimum. Buyer shall guarantee BIP an annual
                       minimum of [*] Bulk Drug Substance Runs (the "Annual
                       Minimum") through [*], subject to the terms of this
                       Agreement. The [*] Bulk Drug Substance Runs is believed
                       to be equivalent to the capacity [*] BIP [*] L
                       fermenters. Subject to Section 5.10(c) below, beginning
                       on [*] and continuing through the end of the Supply Term,
                       Immunex and Wyeth shall have the same ability to reduce
                       the Annual Minimum as they have to reduce the Maximum
                       Request as provided in Section 5.10(a) above and Section
                       5.10(c) below.

                 (c)   Potential Adjustment to the Maximum Request and Annual
                       Minimum. Notwithstanding anything herein to the contrary,
                       if Immunex and Wyeth reasonably determine in good faith
                       that the yearly worldwide market requirements for Bulk
                       Drug Substance will fall below the Annual Minimum for a
                       particular Calendar Year (such calculation to be based on
                       the prior year's Production Assumptions and the basic
                       success rate laid down in Section 5.1(a)(1) of the
                       original Agreement), and Immunex and Wyeth provide
                       written notice thereof to BIP, including a certification

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                       signed by an officer of Immunex and Wyeth that verifies
                       their forecast for worldwide market requirements for Bulk
                       Drug Substance for the respective Calendar Year, then the
                       terms set forth in Section 5.1(b) of the original
                       Agreement regarding downward adjustments in the Maximum
                       Request shall apply and shall supersede the provisions in
                       Section 5.10(a) above regarding revisions to the Maximum
                       Request and the provisions in Section 5.10(b) above
                       regarding revisions to the Annual Minimum. Thereafter,
                       and for so long during the Supply Term that the yearly
                       worldwide market requirements for Bulk Drug Substance
                       remain below the Annual Minimum, and except as otherwise
                       agreed among the Parties, Buyer shall guarantee BIP an
                       adjusted annual minimum (the "Adjusted Annual Minimum")
                       that shall supersede the Annual Minimum. The Adjusted
                       Annual Minimum shall be the greater of (1) [*] contained
                       in the [*] provided to BIP by Immunex and Wyeth for [*]
                       or (2) [*], as such [*] by Immunex and Wyeth pursuant to
                       [*]. If the [*] are higher than the [*] thereof provided
                       by Immunex and Wyeth to BIP [*]shall be adjusted [*].

                       If the [*] is applicable, then [*]. Immunex and Wyeth
                       shall [*] for [*] greater than either (i) [*] or (ii)
                       [*]. Immunex and Wyeth shall in a timely manner inform
                       BIP in writing of [*],

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                       and BIP shall within thirty (30) days after receipt of
                       such notice provide its own written notice to Immunex and
                       Wyeth of which option BIP has selected (i.e., either (i)
                       or (ii) in the immediately preceding sentence).

                       By way of example only, if [*]

     5.   Extension of Supply Term of Agreement. In consideration of BIP's
consent to convert its exclusive manufacturing rights to semi-exclusive
manufacturing rights as described in Paragraph 3 of this Amendment No. 1,
Section 19.1 of the Agreement shall be amended and restated as follows:

          19.1  Term; Renewal.
                Unless sooner terminated pursuant to the terms of this
                Agreement, the term of this Agreement shall commence upon the
                Effective Date and shall continue thereafter until at least [*]
                (the "Supply Term"). This Agreement and the Supply Term shall
                automatically continue from Calendar Year-to-Calendar Year
                thereafter unless terminated by either Party by providing at
                least [*] years' prior

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                written notice to the other Party, provided that neither Party
                may provide such notice prior to the end of the [*] Contract
                Year, i.e., [*]. For purposes of this Section 19.1, Immunex and
                Wyeth shall be deemed the same Party.

     6.   New Article 24. The Agreement shall be amended to add the following
new provision, Article 24, as follows:

                ARTICLE 24.  CONTRACTUAL INCENTIVES TO BIP FOR
                            OUTSOURCING ACTIVITIES

24.1 Costs of Outsourcing; Ordering Additional Runs; [*] Pricing for Additional
     Runs; ROFR; Drug Product and Finished Product Capacity.

     (a)  Costs of Outsourcing. Buyer shall pay [*] percent ([*]%) of the costs
          of BIP's Outsourcing Activities (as defined below), not to exceed DM
          [*] ([*]Deutsche Mark), that are directly related to BIP providing the
          additional Bulk Drug Substance Runs for the Product, as described
          below. These outsourcing costs, which BIP shall further demonstrate
          for Buyer by having BIP's outside auditor provide Buyer prior to any
          payments according to Section 24.1(a)(1) below a letter confirming
          that the DM [*] ([*] Deutsche Mark) figure, or any other amount not to
          exceed such figure (the "Confirmed Outsourcing Costs"), is a fair
          calculation of BIP's costs for Outsourcing Activities, are in the
          order of DM [*] ([*] Deutsche Mark) for technology transfer and DM [*]
          ([*] Deutsche Mark) in loss of profitability.

          For purposes hereof, "Outsourcing Activities" shall mean that BIP has
          and shall forthwith act in good faith and use commercially reasonable
          efforts to diligently and in a timely manner pursue the outsourcing of
          such products that BIP reasonably has determined to be and forthwith
          reasonably determines would be necessary to free-up the [*] Original
          Additional Runs (as defined below) within the [*]month period from [*]
          to [*], which activities shall include BIP's efforts and commitment of
          financial resources (in the order of DM [*] for technology transfer)
          and personnel resources commensurate to those efforts and resources
          that would be employed by BIP to make additional near-term production
          capacity available for a product having similar market potential as
          the Product, it being understood that BIP is not promising the success
          of these efforts nor guaranteeing that it will be able to make
          available the Original Additional Runs.

          (1)   [*] percent ([*]%) of the Confirmed Outsourcing Costs shall be
                paid by Buyer to BIP according to the following schedule:

                (i)    [*] percent ([*]%) of the Confirmed Outsourcing Costs
                       shall be paid when BIP provides a written, binding
                       production schedule (the "Binding Production Schedule")
                       to Buyer that

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                       indicates a total of at least [*] Bulk Drug Substance
                       Runs (comprised of [*] Bulk Drug Substance Runs at the
                       beginning of 2000 carried over from 1999 + [*] Bulk Drug
                       Substance Runs from 2000 + [*] Bulk Drug Substance Runs
                       in the first [*] months of 2001 + at least [*] additional
                       Bulk Drug Substance Runs) over the [*]-month period from
                       [*] to [*], and also indicates a total of at least [*]
                       Bulk Drug Substance Runs (comprised of the [*] carryover
                       Bulk Drug Substance Runs + [*] Bulk Drug Substance Runs
                       in 2000 + [*] Bulk Drug Substance Runs in 2001 + at least
                       [*] additional Bulk Drug Substance Runs) over the [*]-
                       month period from [*] to [*]. Such amount shall be
                       nonrefundable when paid.

                (ii)   [*] percent ([*]%) of the Confirmed Outsourcing Costs
                       shall be paid when BIP provides a Binding Production
                       Schedule to Buyer that indicates a total of at least [*]
                       Bulk Drug Substance Runs (comprised of [*] Bulk Drug
                       Substance Runs at the beginning of 2000 carried over from
                       1999 + [*] Bulk Drug Substance Runs from 2000 + [*] Bulk
                       Drug Substance Runs in the first [*] months of 2001 + at
                       least [*] additional Bulk Drug Substance Runs) over the
                       [*]-month period from [*] to [*], and also indicates a
                       total of at least [*] Bulk Drug Substance Runs (comprised
                       of the [*] carryover Bulk Drug Substance Runs + [*] Bulk
                       Drug Substance Runs in 2000 + [*] Bulk Drug Substance
                       Runs in 2001 + at least [*] additional Bulk Drug
                       Substance Runs) over the [*]-month period from [*] to
                       [*]. Such amount shall be nonrefundable when paid.

                (iii)  [*] percent ([*]%) of the Confirmed Outsourcing Costs
                       shall be paid when BIP provides a Binding Production
                       Schedule to Buyer that indicates a total of [*] Bulk Drug
                       Substance Runs (comprised of [*] Bulk Drug Substance Runs
                       at the beginning of 2000 carried over from 1999 + [*]
                       Bulk Drug Substance Runs from 2000 + [*] Bulk Drug
                       Substance Runs in the first [*] months of 2001 + [*]
                       additional Bulk Drug Substance Runs) over the [*]-month
                       period from [*] to [*], and also indicates a total of [*]
                       Bulk Drug Substance Runs (comprised of the [*] carryover
                       Bulk Drug Substance Runs + [*] Bulk Drug Substance Runs
                       in 2000 + [*] Bulk Drug Substance Runs in 2001 + [*]
                       additional Bulk Drug Substance Runs) over the [*]-month
                       period from [*] to [*]. Such amount shall be
                       nonrefundable when paid.

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                       The additional Bulk Drug Substance Runs to be performed
                       by BIP for Buyer over the [*]-month period from [*] to
                       [*] (each of these additional Bulk Drug Substance Runs
                       shall be referred to as an "Original Additional Run," and
                       collectively, as the "Original Additional Runs") shall be
                       incremental to the [*] Bulk Drug Substance Runs for the
                       Product in 2000 (comprised of the [*] carryover Bulk Drug
                       Substance Runs + [*] Bulk Drug Substance Runs) and the
                       [*] Bulk Drug Substance Runs for the Product in 2001. On
                       each Binding Production Schedule, BIP shall clearly
                       identify to Buyer by asterisk or otherwise which Bulk
                       Drug Substance Runs are the Original Additional Runs. Any
                       subsequent revisions to a Binding Production Schedule
                       must be agreed upon in writing by the Parties.

          (2)  Regardless of whether or not BIP has provided a Binding
               Production Schedule to Buyer under Section 24.1(a)(1) above, [*]
               percent ([*]%) of the Confirmed Outsourcing Costs shall be paid
               by Buyer to BIP on an incremental basis, i.e., Buyer shall pay
               [*] percent ([*]%) of the Confirmed Outsourcing Costs to BIP for
               each Attempted Original Additional Run prior to [*].  For
               purposes hereof, an "Attempted Original Additional Run" shall
               mean that BIP in good faith attempted a Bulk Drug Substance Run
               that advanced to at least [*].

     (b)  Firm Order for the Original Additional Runs.  Buyer hereby issues a
          Firm Order for all of the Original Additional Runs made available
          during the period from [*] through [*].  Such Firm Order shall
          constitute a binding order for every Original Additional Run that BIP
          makes available as set forth in the Binding Production Schedule or as
          otherwise agreed upon in writing by the Parties, not to exceed [*]
          Original Additional Runs without Buyer's prior written approval.  As
          the Parties are of the common opinion that any Original Additional Run
          would be the result of BIP's good faith outsourcing activities with
          the goal of providing additional near-term Bulk Drug Substance Runs
          for the Product, BIP shall in no way be liable to Buyer or anybody
          else for the non-fulfillment of such Firm Orders for the Original
          Additional Runs.

     (c)  [*] Pricing.  The Bulk Drug Substance price shall be set at a total of
          DM [*]/gram for each Bulk Drug Substance Run greater than

          (1)  [*] Bulk Drug Substance Runs (comprised of the [*] carryover Bulk
               Drug Substance Runs + [*] Bulk Drug Substance Runs in 2000 + [*]
               Bulk Drug Substance Runs in the first [*] months of 2001) that is
               performed over the [*]-month period from [*]to [*],

          (2)  [*] Bulk Drug Substance Runs (comprised of the [*] carryover Bulk
               Drug Substance Runs + [*] Bulk Drug Substance

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               Runs in 2000 + [*] Bulk Drug Substance Runs in 2001) that is
               performed over the [*]-month period from [*]to [*], provided,
               however, that any Bulk Drug Substance Run eligible for [*]
               pricing under Section 24.1(c)(1) above shall not be eligible for
               [*] pricing under this Section 24.1(c)(2), and

          (3)  [*] Bulk Drug Substance Runs that is performed per year for
               Calendar Years [*] (for each of these [*] Calendar Years, the
               additional Bulk Drug Substance Runs made available by BIP to
               Buyer in the particular Calendar Year shall be referred to as the
               "Subsequent Additional Runs"), provided, however, that the number
               of Bulk Drug Substance Runs that are performed in each of [*]
               (for the last [*] months of [*]) [*] that are eligible for the
               [*] pricing shall not exceed the difference between the number of
               actual Bulk Drug Substance Runs that are performed between [*]to
               [*] and [*] Bulk Drug Substance Runs (comprised of the [*]
               carryover Bulk Drug Substance Runs + [*] Bulk Drug Substance Runs
               in 2000 + [*] Bulk Drug Substance Runs in 2001).

          [*]

     (d)  BIP Written Notice of Subsequent Additional Runs; ROFR for Subsequent
          Additional Runs.

          (1)  By [*], BIP shall provide written notice to Buyer of the number
               of Subsequent Additional Runs that are available in [*].By [*],
               BIP shall provide written notice to Buyer of the number of
               Subsequent Additional Runs that are available in [*].

          (2)  Buyer shall have the right of first refusal as to any Third
               Parties (the "ROFR") to order any or all of such Subsequent
               Additional Runs in [*] and [*] to the extent provided in this
               paragraph, in either Calendar Year not to exceed [*] Subsequent
               Additional Runs without Buyer's prior written approval.  This
               ROFR for Subsequent Additional Runs with respect to [*] and [*],
               respectively, shall be exercised by Buyer, if at all, by
               providing written notice to BIP, within [*] days after BIP's
               written notice to Buyer of the number of Subsequent Additional
               Runs that BIP would make available in [*] or [*], as applicable,
               of that number of such Subsequent Additional Runs for which Buyer
               thereby issues a Firm Order (the "Accepted Subsequent Additional
               Runs").  Upon receipt of any such notice from Buyer, such Firm
               Orders shall constitute binding orders, and BIP shall dedicate
               all of such Accepted Subsequent Additional Runs for the
               production of Bulk

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               Drug Substance.

     (e)  Potential Refund of Confirmed Outsourcing Costs.  If BIP does not
          attempt at least [*] Accepted Subsequent Additional Runs in [*], then
          no later than [*], BIP shall refund to Buyer a total of [*] percent
          ([*]%) of the Confirmed Outsourcing Costs previously paid by Buyer for
          the Original Additional Runs under Section [*] above.

     (f)  Drug Product and Finished Product Capacity.  BIP hereby undertakes to
          maintain sufficient manufacturing capacity and a sufficient number of
          employees with such expertise and experience as is necessary or
          appropriate to convert the Bulk Drug Substance Lots resulting from the
          Original Additional Runs and the Accepted Subsequent Additional Runs
          into Drug Product and, if ordered, Finished Product, in accordance
          with the terms hereof, including without limitation, Section 4.3
          hereof.

24.2  Additional Contractual Incentives for Unsuccessful Outsourcing Activities.
     Instead of, and not in addition to, the contractual incentives and other
     terms provided to BIP in Section 24.3 below for Successful Outsourcing
     Activities (as defined below), BIP shall receive the following contractual
     incentives and be subject to the following terms set forth in this Section
     24.2 as a result of Unsuccessful Outsourcing Activities, or alternatively,
     under the conditions specified in Section 24.3(e) below.  For purposes
     hereof, "Unsuccessful Outsourcing Activities" shall mean that despite BIP's
     Outsourcing Activities, BIP has been unable to provide Buyer at least [*]
     successful harvests (i.e., Bulk Drug Substance Runs resulting in vialed and
     released Drug Product within customary timeframes after each harvest) by
     [*].

     (a)  Bulk Drug Substance Cost.  The cost of Bulk Drug Substance shall be
          fixed at DM [*]/gram, except for (1) Bulk Drug Substance that is [*]
          priced at DM [*]/gram under Section 24.1(c) above, (2) the potential
          annual price adjustments resulting from the [*] yield sharing between
          BIP and Buyer beginning [*] as described in Section 24.2(b) below and
          (3) the price adjustments permitted under Sections 5.6(a), 5.6(b) and
          5.6(c) hereof.

     (b)  Yield Enhancement.  BIP and Buyer shall share the benefit of all
          accrued yield increases from production of Bulk Drug Substance Lots on
          a [*] basis (i.e., accrued yield increases shall be measured from the
          Production Assumptions that were in effect on the Effective Date of
          the Agreement through the Production Assumptions calculated with
          respect to production through [*]), to be computed annually pursuant
          to Section 5.3(b) hereof beginning with the first potential annual
          price adjustment effective [*], provided, however, that the formula
          and example set forth in Section 5.3(b) hereof shall be adjusted to
          reflect such [*] sharing of any price adjustments.

     (c)  Risk Sharing.  Beginning with respect to Calendar Year [*], BIP and
          Buyer

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          shall each Calendar Year share on a [*] basis the costs of Bulk Drug
          Substance Runs that do not meet the Bulk Drug Substance Specifications
          (calculated on the basis of the Product Price and original Production
          Assumptions hereunder less [*]% for profit), but only to the extent
          that those failed Bulk Drug Substance Runs represent a failure rate
          greater than [*] percent ([*]%) of all the Bulk Drug Substance Runs
          performed during that Calendar Year [*]. Buyer's payment obligations
          for such Bulk Drug Substance Runs as set forth above shall only apply
          to the extent that a Bulk Drug Substance Run failed at the [*] in the
          Process. BIP shall accept the risk of the first [*] percent ([*]%) of
          Bulk Drug Substance Runs each Calendar Year that fail at the [*] in
          the Process. Buyer's payment obligations under this Section 24.2(c)
          shall be deemed to satisfy any payment obligations of Buyer under the
          provisions of Section 6.3 hereof to the extent any such provisions
          could be construed to require Buyer to pay any portion of the cost of
          Bulk Drug Substance Runs that do not meet the Bulk Drug Substance
          Specifications.

24.3 Contractual Incentives for Successful Outsourcing Activities.  Instead of,
     and not in addition to, the contractual incentives and other terms provided
     to BIP in Section 24.2 above for Unsuccessful Outsourcing Activities, BIP
     shall receive the following contractual incentives and be subject to the
     following terms set forth in this Section 24.3 in the event that BIP's
     efforts have resulted in Successful Outsourcing Activities, except as
     otherwise set forth in Section 24.3(e) below.  For purposes hereof,
     "Successful Outsourcing Activities" shall mean that as a result of BIP's
     Outsourcing Activities, BIP has achieved at least [*] successful harvests
     (i.e., Bulk Drug Substance Runs resulting in vialed and released Drug
     Product within customary timeframes after each harvest) by [*]:

     (a)  Bulk Drug Substance Cost.  The cost of Bulk Drug Substance shall be
          fixed at DM [*]/gram, except for (1) Bulk Drug Substance that is [*]
          priced at DM [*]/gram under Section 24.1(c) above, (2) the potential
          annual price adjustments resulting from the [*] yield sharing between
          BIP and Buyer [*] as described in Section 24.3(b) below and (3) the
          price adjustments permitted under Sections 5.6(a), 5.6(b) and 5.6(c)
          hereof.

     (b)  Yield Enhancement.  BIP shall [*].  Thereafter, BIP and Buyer shall
          share the benefit of all accrued yield increases from production of
          Bulk Drug Substance Lots on a [*] basis (i.e., accrued yield increases
          shall be measured from the Production Assumptions that were in effect
          on the Effective Date of the Agreement through the Production
          Assumptions calculated with respect to production through [*]), to be
          computed annually pursuant to Section 5.3(b) hereof beginning with the
          first potential annual price

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          adjustment effective [*], provided, however, that the formula and
          example set forth in Section 5.3(b) hereof shall be adjusted to
          reflect such [*] sharing of any price adjustments.

     (c)  Risk Sharing.  Beginning with respect to Calendar Year [*] and
          continuing with Calendar Years [*], BIP shall accept [*] percent
          ([*]%) of the risk that Bulk Drug Substance Runs do not meet the Bulk
          Drug Substance Specifications. In Calendar Year [*] and then beginning
          again with respect to Calendar Year [*] and thereafter for subsequent
          Calendar Years through the end of the Supply Term, BIP and Buyer shall
          each Calendar Year share on a [*] basis the costs of Bulk Drug
          Substance Runs that do not meet the Bulk Drug Substance Specifications
          (calculated on the basis of the Product Price and original Production
          Assumptions hereunder less [*]% for profit), but only to the extent
          that those failed Bulk Drug Substance Runs represent a failure rate
          greater than [*] percent ([*]%) of all the Bulk Drug Substance Runs
          performed during that Calendar Year. Buyer's payment obligations for
          such Bulk Drug Substance Runs as set forth above shall only apply to
          the extent that a Bulk Drug Substance Run failed at the [*] in the
          Process. BIP shall accept the risk of the first [*] percent ([*]%) of
          Bulk Drug Substance Runs each Calendar Year that fail at the [*] in
          the Process. Buyer's payment obligations under this Section 24.3(c)
          shall be deemed to satisfy any payment obligations of Buyer under the
          provisions of Section 6.3 hereof to the extent any such provisions
          could be construed to require Buyer to pay any portion of the cost of
          Bulk Drug Substance Runs that do not meet the Bulk Drug Substance
          Specifications.

     (d)  Reconciliation.  While the Parties will not know if BIP has achieved
          Successful Outsourcing Activities until [*], the yield enhancement
          provisions under Section 24.2(b) above contemplate shared savings from
          yield enhancements beginning on [*].  Therefore, if BIP has achieved
          Successful Outsourcing Activities, then within a reasonable time after
          [*], the Parties shall reconcile any shared savings during the first
          [*] months of [*] with the applicable yield enhancement provisions
          under Section 24.3(b) above.

     (e)  Reversion to Terms in Section 24.2.  If BIP either provides written
          notice to Buyer under Section 24.1(d) above that BIP will not make
          available at least [*] Subsequent Additional Runs in [*] or [*], or if
          BIP in fact does not attempt at least [*] Subsequent Additional Runs
          in [*] or [*], then from [*] of either [*] or [*], as the case may be
          depending on which is the first Calendar Year for which BIP provides
          notice that it will not make available at least [*] Subsequent
          Additional Runs or does not in fact attempt such [*] Subsequent
          Additional Runs, and through the remainder of the Supply Term, the
          terms and conditions in Section 24.3(a) - (c) applicable to Successful
          Outsourcing Activities shall

[*] Confidential Treatment Requested

                                       12
<PAGE>

          revert to and be superseded by the terms and conditions in Section
          24.2(a) - (c) applicable to Unsuccessful Outsourcing Activities,
          provided, however, that upon such reversion, in no event shall (1) BIP
          have any obligation to refund to Buyer any benefits which had accrued
          to BIP from yield enhancement in earlier Calendar Years under Section
          24.3(b) above, or (2) Buyer have any additional obligation to BIP for
          risk sharing costs in earlier Calendar Years under Section 24.2(c)
          above.

     7.   Rhode Island Manufacturing Facility. BIP shall provide the assistance
to Immunex and Wyeth in the transfer of technology related to manufacture of the
Product to Wyeth's manufacturing facility in West Greenwich, Rhode Island in a
separate agreement of even date herewith, in which the Parties have agreed upon
the requested activities, timelines, manpower and financial terms.

     8.   Effect of Amendment No. 1 on Agreement. Except as otherwise set forth
in this Amendment No. 1, all other terms and provisions of the Agreement shall
remain in full force and effect. In the event of any conflict between the terms
and conditions of the Agreement and the terms and conditions of this Amendment
No. 1, the terms and conditions of this Amendment No. 1 shall control.

     9.   Counterparts. 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.

     IN WITNESS WHEREOF, the Parties have, by their duly authorized persons,
executed this Amendment No. 1 as of the Amendment Effective Date.

IMMUNEX CORPORATION                 AMERICAN HOME PRODUCTS
                                    CORPORATION, acting through its
                                    Wyeth-Ayerst Laboratories division

By: /s/ Peggy V. Phillips             By: /s/ Kenneth J. Martin
   -------------------------------       ---------------------------------

Name: Peggy V. Phillips               Name: Kenneth J. Martin
     -----------------------------         -------------------------------

Title: Executive VP & COO             Title: Sr. Vice President & Chief
      ----------------------------          ------------------------------
                                             Financial Officer
                                            ------------------------------

Date:  6/27/00                        Date: 6/27/00
     -----------------------------         -------------------------------

BOEHRINGER INGELHEIM PHARMA KG
ppa.                                  ppa.

By: /s/ Wolfram Carius                By: /s/ Rolf Werner
   -------------------------------       ---------------------------------

Name: Wolfram Carius                  Name: Rolf Werner
     -----------------------------         -------------------------------

Title: Head of Aidpharm Manuf.        Title: CD Biopharmaceuticals
      ----------------------------          ------------------------------

Date: 30.06.00                        Date: 30.06.00
     -----------------------------         -------------------------------

                                       13
</TEXT>
</DOCUMENT>
