<PAGE>

                                                                    EXHIBIT 10.1

*Certain confidential information contained in this document, marked by
brackets, has been omitted and filed with the Securities and Exchange Commission
pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

                        SETTLEMENT AND LICENSE AGREEMENT

      This Settlement and License Agreement ("AGREEMENT") is made and entered by
and among Biogen Idec Inc., a Delaware corporation ("Biogen Idec"), Corixa
Corporation, a Delaware Corporation ("Corixa"), Coulter Pharmaceutical, Inc., a
Delaware Corporation ("Coulter"), The Regents of the University of Michigan, a
constitutional corporation of the State of Michigan ("Michigan"), and SmithKline
Beecham Corporation d/b/a GlaxoSmithKline, a Pennsylvania Corporation ("GSK")
(collectively the "PARTIES"). The EFFECTIVE DATE of this AGREEMENT is February
27, 2004.

                                    RECITALS

      1. Certain disputes and controversies have arisen between the PARTIES
relating to the claims, counter-claims, cross-claims, and demands set forth in
the following civil actions ("THE LAWSUITS"):

            a. Southern District of California Case No. 01-CV-1637 IEG (RBB): On
September 10, 2001, IDEC Pharmaceuticals Corp. ("IDEC") filed a complaint in the
Southern District of California against Corixa, Coulter and Michigan for a
declaratory judgment of patent non-infringement and invalidity of U.S. Patents
6,015,542, 6,090,365, 5,595,721, 5,843,398, 6,251,362, and 6,022,521. This was
assigned Case No. 01-CV-1637 IEG (RBB). On September 12, 2001, IDEC filed a
First Amended Complaint, adding a claim for declaratory judgment of patent
non-infringement and invalidity of U.S. Patent 6,287,537. On February 13, 2002,
Corixa, Coulter, Michigan and GSK filed a counterclaim alleging patent
infringement of U.S. Patents 5,595,721, 6,015,542, and 6,090,365. On August 13,
2002, Corixa, Coulter, GSK and Michigan amended their counterclaim to include a
claim for infringement of U.S. Patent 6,287,537.

            b. District of Delaware Case No. 01-615; Southern District of
California Case 02-CV-0508 IEG (RBB): On September 12, 2001, Corixa, Coulter,
and GSK filed a complaint in the District Court of Delaware against IDEC
alleging patent infringement and for a declaratory judgment of infringement of
U.S. Patents 5,595,721, 6,015,542, and 6,090,365. This was assigned Case No.
01-615. On September 28, 2001, Corixa, Coulter, Michigan and GSK filed an
Amended Complaint, adding Michigan as a plaintiff. Pursuant to a motion to
transfer, this case was transferred to the Southern District of California and
assigned Case No. 02-CV-0508 IEG (RBB). The case was consolidated with Case No.
01-CV-1637 IEG (RBB), and pursuant to court order, was then referred to as Case
No. 01-CV-1637 IEG (RBB). Corixa, Coulter, GSK and Michigan filed an Amended
Complaint, adding a cause of action for patent infringement of U.S. Patent No.
6,287,537. IDEC has filed counterclaims for declaratory judgment of patent
non-infringement and invalidity of U.S. Patents 6,015,542, 6,090,365, 5,595,721,
and 6,287,537.

<PAGE>

            c. Southern District of California Case No. 03-CV-00380 IEG (RBB):
On February 25, 2003, IDEC filed a complaint in the Southern District of
California against Corixa, Coulter and GSK for infringement of U.S. Reissue
Patent No. RE 38,008. This was assigned Case No. 03-CV-00380 IEG (RBB). On April
1, 2003, GSK filed a counterclaim for a declaratory judgment of
non-infringement, invalidity, unenforceability and for interference with
contractual relations. The cause of action for interference with contractual
relations was dismissed by the Court on September 30, 2003. On August 18, 2003,
Corixa and Coulter filed a counterclaim for a declaratory judgment of
non-infringement, invalidity and unenforceability of U.S. Reissue Patent No. RE
38,008.

            d. Southern District of California Case No. 03-CV-1093 IEG (RBB): On
June 2, 2003, IDEC filed a complaint against Corixa, Coulter, Michigan and GSK
for declaratory judgment of non-infringement, invalidity and unenforceability of
U.S. Patent No. 6,565,827. In December, 2003, Corixa, Coulter, Michigan and GSK
provided a covenant not to sue Biogen Idec for infringement as to any claim of
the `827 patent:

            "Patentees Corixa Corporation, Coulter Pharmaceuticals, the
            University of Michigan and SmithKline Beecham d/b/a GlaxoSmithKline
            unconditionally agree not to sue Biogen IDEC for infringement as to
            any claim of the `827 patent based upon the Zevalin(TM) or the
            Zevalin(TM) Therapeutic Regimen as previously or currently
            manufactured and sold or any Zevalin(TM) or the Zevalin(TM)
            Therapeutic Regimen as currently approved by the FDA. By this,
            Patentees' representation to Biogen IDEC extends to infringement for
            any current or past off label use."

Based upon this covenant not to sue, Biogen Idec dismissed the action without
prejudice. This covenant not to sue is memorialized in the following letters:
the December 11, 2003, letter from William G. Gaede (counsel for Corixa,
Coulter, and Michigan) to James J. Elacqua (counsel for Biogen Idec), and in the
December 15, 2003, and December 16, 2003, letters from Martin I. Fuchs (counsel
for GSK) to F.T. Alexandra Mahaney (counsel for Biogen Idec), all of which are
attached to the Notice of Voluntary Dismissal Without Prejudice filed in this
case (the "'827 COVENANT NOT TO SUE"). Notwithstanding this AGREEMENT, this '827
COVENANT NOT TO SUE remains in effect.

      2. On November 12, 2003, Biogen, Inc. merged with a wholly owned
subsidiary of IDEC and IDEC changed its name to "Biogen Idec Inc." On or about
November 13, 2003, a Notice of Name Change was filed in THE LAWSUITS changing
the name of IDEC to Biogen Idec.

      3. Following a course of negotiations and mediation among the PARTIES
hereto and their respective counsel, the PARTIES on February 27, 2004, agreed to
settle and compromise all disputes, claims and controversies among them relating
to the PATENTS IN SUIT, including all claims, counter-claims and cross-claims
that were asserted in THE LAWSUITS by any of the PARTIES.

                                       2
<PAGE>

                                   DEFINITIONS

      1. "THE KAMINSKI PATENT FAMILY" shall mean (i) U.S. Patents No. 6,015,542,
6,090,365, 5,595,721, 5,843,398, 6,287,537, and 6,565,827; (ii) any patents,
including, without limitation, any United States, international or foreign
national or regional patents that issue from counterparts applications,
continuations, continuations-in-part, divisionals or continued prosecution or
renewal applications of any patent application from which any of the foregoing
patents set forth in subsection (i) claims priority; and (iii) any patents,
including, without limitation, any United States, international or foreign
national or regional patents resulting from counterpart applications, reissues,
reexaminations, extensions, interferences or oppositions of any of the
foregoing.

      2. "THE WAHL PATENT FAMILY" shall mean (i) U.S. Patents No. 6,251,362, and
6,022,521; (ii) any patents, including, without limitation, any United States,
international or foreign national or regional patents that issue from
counterparts applications, continuations, continuations-in-part, divisionals or
continued prosecution or renewal applications of any patent application from
which any of the foregoing patents set forth in subsection (i) claims priority;
and (iii) any patents, including, without limitation, any United States,
international or foreign national or regional patents resulting from counterpart
applications, reissues, reexaminations, extensions, interferences or oppositions
of any of the foregoing.

      3. "THE NEORX PATENT FAMILY" shall mean (i) U.S. Reissue Patent No. RE
38,008; (ii) any patents, including, without limitation, any United States,
international or foreign national or regional patents that issue from
counterparts applications, continuations, continuations-in-part, divisionals or
continued prosecution or renewal applications of any patent application from
which any of the foregoing patents set forth in subsection (i) claims priority;
and (iii) any patents, including, without limitation, any United States,
international or foreign national or regional patents resulting from counterpart
applications, reissues, reexaminations, extensions, interferences or oppositions
of any of the foregoing.

      4. "PATENTS IN SUIT" shall mean THE KAMINSKI PATENT

      5. FAMILY, THE WAHL PATENT FAMILY and THE NEORX PATENT FAMILY.

      6. "ZEVALIN KITS" refers to: (a) any kit containing Ibritumomab Tiuxetan
for the preparation of Indium-111 Ibritumomab Tiuxetan and Yttrium-90
Ibritumomab Tiuxetan as currently formulated and approved by the FDA, together
with any [*] thereon related to the treatment of any [*]; (b) any modification
to the kit described in subpart (a) resulting from a [*] to the [*], or from a
separate [*] that could have been [*] with the [*] as a [*] to the [*] as
determined by the then-current [*] governing the [*] of [*] and [*]; and (c) any
modification to the kit described in subpart (a) that consists of [*] the [*] as
currently approved into [*] and/or [*] to [*] [*] of the [*] (such as [*] to [*]
Indium-111 Ibritumomab Tiuxetan). ZEVALIN KITS does not include: (a) the use of
ZEVALIN KITS for any indication other than [*]; or (b) any products requiring
the [*] of a [*].

      7. "NET SALES" shall mean the gross invoiced sales prices charged for all
ZEVALIN KITS sold by Biogen Idec, its AFFILIATES or ZEVALIN SUBLICENSEES (but
with respect to

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       3
<PAGE>

ZEVALIN SUBLICENSEES, only in the circumstances described in the last sentence
of definition 11 below) during a CALENDAR YEAR for ultimate use in the United
States, after deduction of the following items:

            a.    trade, quantity, allowances or cash discounts;

            b.    amounts repaid or credited by reason of rejection or return of
                  previously sold products, or for rebates or retroactive price
                  reductions (including, without limitation, Medicaid, Medicare,
                  government, commercial and similar types of rebates);

            c.    all taxes and other governmental charges levied on sale,
                  delivery or use, as applicable (excluding income taxes of any
                  kind);

            d.    transportation costs prepaid or allowed and costs of insurance
                  in transit, customs duties, surcharges and other governmental
                  charges, to the extent expressly set forth as part of the
                  gross invoiced sales price to the THIRD PARTY;

            e.    except where redundant with amounts in subparagraph (b) above,
                  credits or allowances given or made for wastage replacement;
                  and

            f.    periodic adjustment of the provision determined in subsections
                  (a) to (e) to reflect amounts actually incurred.

For the purposes of this NET SALES definition:

            (i) Any "sale" that occurs other than in an arm's-length transaction
for fair market value shall be deemed to have occurred at a NET SALES amount
equal to the average invoice price for the selling party, less the average
permissible deductions for sales occurring during that year for the selling
party in arm's-length transactions. If the selling party did not have any
arm's-length transactions for fair market value during that year, then such
sales shall be deemed to have occurred at a NET SALES amount equal to the fair
market value of ZEVALIN KITS at that stage of the distribution chain in the
United States, as determined by the price charged in arm's-length transactions
by other parties at such stage of the distribution chain in the United States
during such calendar year or other evidence of such fair market value.

            (ii) A "sale" is deemed to occur upon the earlier to occur of the
date the ZEVALIN KITS are shipped or the date of invoice to the purchaser of the
ZEVALIN KITS.

            (iii) A sale of ZEVALIN KITS among or between Biogen Idec and its
AFFILIATES for resale of such ZEVALIN KITS by Biogen Idec or any such AFFILIATE
shall not be considered a sale for purposes of this provision. In the case of
sales by Biogen Idec or any AFFILIATE to ZEVALIN SUBLICENSEES: (a) except as
expressly provided in the last sentence of definition 11, sales to the ZEVALIN
SUBLICENSEE shall constitute NET SALES (and the further resale of such ZEVALIN
KITS by the ZEVALIN SUBLICENSEE shall be omitted from NET SALES), and (b) in the
case described in the last sentence in definition 11 in which the resale by the
ZEVALIN SUBLICENSEE is included in NET SALES, then the sale of the ZEVALIN KIT
by Biogen Idec or any AFFILIATE to the ZEVALIN SUBLICENSEE shall be omitted from
NET SALES.

                                       4
<PAGE>

            (iv) A "sale" shall not include transfers or other distributions or
dispositions of ZEVALIN KITS, at no-charge, for pre-clinical, clinical or
regulatory purposes or to physicians or hospitals for promotional purposes or as
free goods supplied to indigent patients or in connection with compassionate use
or similar programs.

            (v) "Sales" shall also exclude sales of ZEVALIN KITS for ultimate
use in a country outside of the United States, noting that, in this regard, the
calculation of NET SALES shall exclude ZEVALIN KITS which are sold in the United
States for ultimate use in a country outside of the United States, but shall
include ZEVALIN KITS which are sold outside of the United States for ultimate
use in the United States where such use is intended and licensed by Biogen Idec
or its Affiliates.

            (vi) If Biogen Idec or any of its AFFILIATES or any ZEVALIN
SUBLICENSEES bundles the sale of ZEVALIN KITS with the sale of any other product
or service, the portion of the bundled price included in NET SALES shall be the
portion of such bundled price allocable to the fair value of the ZEVALIN KITS
relative to the fair value of the other elements of the bundled sale (determined
on the basis of what would have been charged by Biogen Idec or any such
AFFILIATE or ZEVALIN SUBLICENSEE to an unrelated purchaser in an arm's length
transaction).

            (vii) If Biogen Idec, its AFFILIATES or ZEVALIN SUBLICENSEES (to the
extent provided in the last sentence of definition 11) collect additional
payments from a purchasing party, calculated based upon sales of ZEVALIN KITS
which are in addition to, and where NET SALES have been calculated from, the
gross invoiced sales price to such purchasing party for such ZEVALIN KITS (e.g.,
in the form of royalties or comparable payments based on resales of ZEVALIN KITS
by such purchasing party), then such additional payments shall also be included
in calculating NET SALES as received.

      8. "THIRD PARTY(IES)" shall mean any person or entity other than a PARTY
to this AGREEMENT or their respective AFFILIATES or its or their SUBLICENSEES.

      9. "THE ASSERTED CLAIMS" mean claims 1-4, 8, 10, 14, 18, and 22 of U.S.
Patent 6,595,721; claims 1-3, 7-8 and 10 of U.S. Patent 6,015,542; claims 1-2,
4-5, 7, 19-20, and 23-27 of U.S. Patent No. 6,090,365; and claims 1, 3, 7-9, 11,
13, 15-16, 19-21, 23, 25, 27-28, 31-33, 35, 37, 39-41, 44-46, 48, 50 and 52 of
U.S. Patent 6,287,537.

      10. "AFFILIATES" shall mean with respect to any person or entity, any
other person or entity, which controls, is controlled by or is under common
control with such person or entity. A person or entity shall be regarded as in
control of another entity if it owns or controls, directly or indirectly, (i) in
the case of corporate entities at least fifty percent (50%) (or the maximum
ownership interest permitted by law, if less than 50%) of the equity securities
in the subject entity entitled to vote in the election of directors, and (ii) in
the case of an entity that is not a corporation, at least fifty percent (50%)
(or the maximum ownership interest permitted by law, if less than 50%) of the
equity securities or other ownership interests with the power to direct the
management and policies of such entity or entitled to elect the corresponding
management authority.

                                       5
<PAGE>

      11. "SUBLICENSEE" shall mean any entity or person to whom (i) Biogen Idec
has granted (whether before or after the EFFECTIVE DATE) a right to make, have
made, use, offer to sell, sell or import a product covered by any of THE
KAMINSKI PATENT FAMILY or THE WAHL PATENT FAMILY or (ii) Corixa, Coulter,
Michigan and GSK has granted (whether before or after the EFFECTIVE DATE) a
right to make, have made, use, offer to sell, sell or import a product covered
by any of THE NEORX PATENT FAMILY.

      12. "ZEVALIN SUBLICENSEE" shall mean any entity or person to whom Biogen
Idec has granted (whether before or after the EFFECTIVE DATE) a right to make,
use, sell, offer to sell or import the ZEVALIN KITS, but shall not include any
of the following: (a) any [*], [*] or [*] or facility to the extent it is a
recipient of ZEVALIN KITS for [*] and/or [*] to one or more [*]; (b) any [*] or
[*] health [*] to the extent it is a recipient of ZEVALIN KITS for [*] and/or
[*] to one or more [*]; and (c) any [*], [*], [*] health [*] to the extent [*]
or [*] [*], and/or [*] ZEVALIN to one or more [*]. Notwithstanding any provision
herein to the contrary, sales of ZEVALIN KITS by ZEVALIN SUBLICENSEES shall be
included within NET SALES only if the ZEVALIN SUBLICENSEE in question has
contractually agreed with [*] or an [*] to perform (whether itself or through
others), and is substantially responsible for, the [*] and [*] of the ZEVALIN
KITS; provided, however, that a party entering into a [*] or [*] with Biogen
Idec or an AFFILIATE in which Biogen Idec or the AFFILIATE [*] the [*] from the
ZEVALIN KITS is not intended to be construed as a ZEVALIN SUBLICENSEE for
purposes of the preceding sentence.

      13. "CALENDAR YEAR" shall mean the period from January 1st through
December 31st.

                                    AGREEMENT

            Now, therefore, in consideration of the mutual covenants and
agreements contained herein, the sufficiency of which is acknowledged, the
PARTIES agree as follows:

      1. DISMISSAL OF LAWSUITS: The PARTIES shall not pursue any further
proceedings in THE LAWSUITS and shall dismiss with prejudice all respective
claims, cross-claims and counterclaims pending in THE LAWSUITS. Within five days
of execution of this AGREEMENT, the PARTIES shall sign the two attached Notices
of Stipulated Dismissal With Prejudice Of All Claims And Counterclaims. Biogen
Idec shall cause these Stipulations to be filed with the Court, and shall
provide the other PARTIES with a filed-stamp copy of the Stipulations upon
receipt.

      2. PAYMENT: Upon execution of this AGREEMENT and in settlement of all
outstanding claims, Biogen Idec will pay to Corixa the sum of twenty million
United States dollars (U.S. $20 million) by wire transfer of immediately
available funds. Such payment shall become non-refundable and non-creditable
against any other amounts due under this AGREEMENT upon entry by the Court of
the Notices of Stipulated Dismissals described in paragraph 1 signed by all
PARTIES. Any wire transfer payments to Corixa under this Agreement shall be made
to the following account, or such other account as Corixa may hereafter
designate in writing:

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       6
<PAGE>

Bank                      The Commerce Bank of Washington
                          601 Union Street, Suite 3600
                          Seattle, WA    98104
ABA Number                125008013
Account                   Corixa Corporation
Account Number            [*]

      3. LICENSE GRANTS:

            3.1 LICENSE TO THE KAMINSKI PATENT FAMILY AND THE WAHL PATENT
FAMILY:

               3.1.1 Corixa, Coulter, Michigan and GSK hereby each grant to
Biogen Idec a worldwide, irrevocable, non-exclusive license to THE KAMINSKI
PATENT FAMILY and THE WAHL PATENT FAMILY for any and all purposes.

               3.1.2 The term of this license shall be from the EFFECTIVE DATE
of this AGREEMENT until the date of expiration of the last-to-expire patent of
THE KAMINSKI PATENT FAMILY and THE WAHL PATENT FAMILY.

               3.1.3 Biogen Idec shall have the irrevocable right to grant
sublicenses to THE KAMINSKI PATENT FAMILY and THE WAHL PATENT FAMILY, provided
that Biogen Idec incorporates terms and conditions into its sublicense
agreements sufficient to enable Biogen Idec to comply with its obligations under
this AGREEMENT and the sublicensee expressly agrees to and accepts that the
terms and conditions of this AGREEMENT are binding upon it.

            3.2 LICENSE TO THE NEORX PATENT FAMILY:

               3.2.1 Biogen Idec hereby grants to each of Corixa, Coulter and
GSK a worldwide, irrevocable, non-exclusive license to THE NEORX PATENT FAMILY
for any and all purposes.

               3.2.2 The term of this license shall be from the EFFECTIVE DATE
of this AGREEMENT until the date of expiration of the last-to-expire patent of
THE NEORX PATENT FAMILY.

               3.2.3 Corixa, Coulter and GSK shall have the irrevocable right to
grant sublicenses to THE NEORX PATENT FAMILY, provided that they incorporate
terms and conditions into their sublicense agreements sufficient to enable
Corixa, Coulter and GSK to comply with their obligations under this AGREEMENT
and the sublicensee expressly agrees to and accepts that the terms and
conditions of this AGREEMENT are binding upon it. Corixa, Coulter and GSK shall
each have the power to grant such sublicenses, subject to any separate agreement
among such parties.

      4. ROYALTY PAYMENTS:

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       7
<PAGE>

            4.1 One Time Sales-Based Milestone Payment: Biogen Idec will make a
one-time payment of five million United States dollars (U.S. $5 million) to
Corixa by wire transfer of immediately available funds within forty-five days of
the end of the first CALENDAR YEAR in which NET SALES exceed the sum of
thirty-five million United States dollars (U.S. $35 million) in that one
CALENDAR YEAR, except as provided in paragraph 4.3 below. Such payment shall be
non-refundable and non-creditable against any other amounts due under this
AGREEMENT.

            4.2 Royalty Payments: Biogen Idec will pay to Corixa a [*] royalty
on NET SALES occurring between [*], and [*], except as provided in paragraph 4.3
below. These royalty payments will be due within forty-five days after the end
of each CALENDAR YEAR during such period, except that the royalty payments with
respect to NET SALES during the first [*] days of [*] shall be made on or before
[*]. Without limitation, this royalty obligation does not apply to any revenues
obtained by Biogen Idec or its AFFILIATES or SUBLICENSEES on the sale of
Rituxan(R) in its non-radiolabeled form.

            4.3 Exceptions to Requirement of Royalty Payments: Notwithstanding
the requirements of paragraphs 4.1 and 4.2, Biogen Idec shall not be obligated
to make either the sales-based milestone payment of paragraph 4.1 or the future
royalty payments of paragraph 4.2 under any of the following circumstances,
provided, however, that any payment made under paragraphs 4.1 and 4.2 prior to
such circumstances shall be non-refundable and non-creditable:

               4.3.1 Biogen Idec shall not be obligated to make any such
payments for any time period after which (a) all of the ASSERTED CLAIMS have
expired or have been declared invalid or unenforceable by a final judgment or
decree in an action brought by or against a THIRD PARTY, that is not further
reviewable because of settlement, exhaustion of all permissible applications for
rehearing or review by a superior tribunal, or expiration of the time permitted
for such applications (such claims being "INVALID"); and (b) there is no other
issued United States patents from THE KAMINSKI PATENT FAMILY with at least one
claim that is not INVALID and that, except for this AGREEMENT, would be
infringed (including contributorily or by inducement ) by the making, use, sale
or offer for sale of the ZEVALIN KITS. Furthermore, if there is any time period
where U.S. Patent No. 6,565,827 is the only patent from THE KAMINSKI PATENT
FAMILY with valid and enforceable claims, Biogen Idec also shall not be
obligated to pay either the sales-based milestone payment of paragraph 4.1 or
the future royalty payments of paragraph 4.2 on the sales of any ZEVALIN KITS
which are covered by the '827 COVENANT NOT TO SUE.

               4.3.2 Biogen Idec shall not be obligated to make any such
payments if a [*] in the [*] of the ZEVALIN KITS, or in the [*] of the [*]
thereof, or in the [*] for which the ZEVALIN KITS are [*], means that the
making, using, selling, offering for sale, or importing of the ZEVALIN KITS
would not, in the absence of the license granted herein or any other license to
THE KAMINSKI PATENT FAMILY, infringe (including contributorily or by inducement)
any claim of any then issued patent of THE KAMINSKI PATENT FAMILY that has not
been determined to be INVALID. Biogen Idec hereby acknowledges that the ZEVALIN
KITS as currently formulated and approved for sale in the United States are
subject to this royalty provision under the ASSERTED CLAIMS of THE KAMINSKI
PATENT FAMILY as currently in effect.

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       8
<PAGE>

               4.3.3 If Biogen Idec believes that any of the royalty payment
exceptions identified in paragraphs 4.3.1 or 4.3.2 is applicable, it shall
provide Corixa with written notice of such belief and the basis thereof and
identify the sales that it believes are subject to such exception (provided,
however, that no sales prior to the date notice is delivered pursuant to this
paragraph 4.3.3 shall be subject to such exception) (the "EXCEPTION SALES"). The
PARTIES agree to resolve any dispute about these issues through the dispute
mechanism of paragraph 12. In pursuing any such dispute resolution with respect
to paragraphs 4.3.1 and 4.3.2 only, the only issue for determination in such
dispute resolution shall be whether the EXCEPTION SALES infringe the claims, as
properly construed, of any then issued patents of THE KAMINSKI PATENT FAMILY
that have not been separately determined to be INVALID and which are not subject
of the `827 COVENANT NOT TO SUE. In pursuing any such dispute resolution with
respect to paragraphs 4.3.1 and 4.3.2 only, the [*] the [*] of certain [*]
appearing in the [*] (the "[*]") shall be [*] with respect to the [*] of: (1)
the ASSERTED CLAIMS; and (2) the [*] appearing in the non-ASSERTED CLAIMS of the
`721, `542, `365 and `537 Patents. However, this [*] shall not be binding on the
[*] of such claims if such claims have been [*] or are the subject of further
[*] (such as a [*] or [*]), and shall not be [*] on the claim [*] of the claims
of any other patent of THE KAMINSKI PATENT FAMILY. A determination that
EXCEPTION SALES are not royalty-bearing shall not affect the royalty-bearing
nature of any other sales of ZEVALIN KITS that are properly the subject of the
royalty provisions hereunder.

               4.3.4 If disputed by Corixa, Biogen Idec will pay Corixa
royalties on the EXCEPTION SALES until it has obtained either the written
consent of Corixa to terminate such payments or a final determination (a
judgment that is not further reviewable because of settlement, exhaustion of all
permissible applications for rehearing or review by a superior tribunal, or
expiration of the time permitted for such applications) that such EXCEPTION
SALES are subject to either the paragraph 4.3.1 or 4.3.2 royalty payment
exception. Any and all royalty payments made on EXCEPTION SALES which sales
occurred after the written notice required by 4.3.3 are refundable as long as
Biogen Idec, within six (6) months of the written notice, files a lawsuit or
initiates an alternative mutually-agreed-upon dispute resolution mechanism to
resolve the issue of whether the royalty payment exception of paragraph 4.3.1
and/or 4.3.2 is applicable. Alternatively, If Biogen Idec does not file a
lawsuit or alternative dispute resolution mechanism within six (6) months of the
written notice, then only those royalty payments made on EXCEPTION SALES which
occurred after the filing of the lawsuit or alternative dispute resolution
mechanism are refundable. If it is determined by agreement or through final
determination that some or all of the EXCEPTION SALES were subject to either the
paragraph 4.3.1 or 4.3.2 royalty payment exception, then, within forty-five (45)
days of such determination or agreement, Corixa will refund to Biogen Idec any
and all such refundable royalties paid on those EXCEPTION SALES plus interest at
the rate of two percent (2%) over prime rate of interest as published in the
Federal Reserve Bulletin H.15 or a successor bulletin thereto calculated from
the date of receipt by Corixa. Interest shall be compounded annually, on each
January 1. GSK will be [*] Corixa for the payment to Biogen IDEC of this refund
plus interest.

            4.4 Sales by AFFILIATES and ZEVALIN SUBLICENSEES: If Biogen Idec
authorizes any AFFILIATE or ZEVALIN SUBLICENSEE to sell ZEVALIN KITS or any part
thereof that creates a royalty obligation under this AGREEMENT, such agreement
shall include an obligation for such AFFILIATE or ZEVALIN SUBLICENSEE to account
for and report its

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       9
<PAGE>

NET SALES of ZEVALIN KITS in the same manner as if such sales had been made by
Biogen Idec, and Biogen Idec shall pay royalties to Corixa as if the sales of
such AFFILIATE or ZEVALIN SUBLICENSEE had been sales of Biogen Idec.

            4.5 Reports: As to any CALENDAR YEAR from 2004 through [*], Biogen
Idec shall within forty-five (45) days of the end of such CALENDAR YEAR furnish
Corixa a written report of NET SALES of ZEVALIN KITS in the United States during
such preceding CALENDAR YEAR (except that such report for the first [*] days of
the year [*] shall be due [*]). Such report shall include the determination of
NET SALES, setting forth the quantity of units sold and otherwise distributed,
amount of gross receipts and deductions taken from gross receipts to arrive at
NET SALES and the determination of royalty owed on NET SALES. Concurrently with
each report, Biogen Idec shall make the royalty payment then due to Corixa.
Payments shall be in U.S. dollars, and, unless, otherwise agreed in writing,
shall be made by wire transfer of immediately available funds to such account of
Corixa as Corixa may from time to time designate in writing. If no royalties are
due, the report shall so state.

            4.6 Audits: Biogen Idec shall keep, and shall exercise commercially
reasonable efforts to cause those AFFILIATES and ZEVALIN SUBLICENSEES identified
in paragraph 4.4 to keep, true, complete and accurate records of all sales of
ZEVALIN KITS upon which royalties are due in accordance with GAAP, and in
sufficient detail to confirm the accuracy of Biogen Idec's royalty calculations.
At Corixa's request and expense, Biogen Idec shall permit, no more than once in
a twelve month period, an independent certified public accountant, appointed by
Corixa and acceptable to Biogen Idec, to examine, at Biogen Idec's principal
place of business, upon reasonable notice and at reasonable times, the records
of Biogen Idec and such records as Biogen Idec collects from those AFFILIATES
and ZEVALIN SUBLICENSEES identified in paragraph 4.4, solely to the extent
necessary to verify the royalty calculations; provided that Biogen Idec may
require such accountant to enter into a customary confidentiality agreement.
Biogen Idec shall be responsible for providing access to such records that in
the ordinary course of business are in the possession or control of those
AFFILIATES and ZEVALIN SUBLICENSEES identified in paragraph 4.4. Such
examination shall be limited to a period of time no more than three (3) years
immediately preceding the request for examination. The report of any such
examination shall be made simultaneously to Corixa and Biogen Idec and shall
simply report the amount, if any, by which Biogen Idec has overpaid or underpaid
its royalties. If Biogen Idec's royalties are found to be in error such that
royalties to Corixa were underpaid, then Biogen Idec shall promptly pay the
deficiency plus interest at the rate of two percent (2%) over prime rate of
interest as published in the Federal Reserve Bulletin H.15 or a successor
bulletin thereto, from time to time (with interest to be compounded annually, on
each January 1); and if royalties to Corixa were underpaid by more than five
percent (5.0%), then Biogen Idec shall additionally reimburse Corixa for its
reasonable out-of-pocket costs incurred in examining such records. In the event
that an audit determines that Biogen Idec has overpaid royalties to Corixa for
one or more audited CALENDAR YEARS, Biogen Idec shall be entitled to credit any
such overpayment against royalties payable in the next CALENDAR YEAR. Corixa
shall treat all financial information subject to review under this Section 4.6
as confidential, and shall cause its accounting firm to treat all such financial
information in confidence. Biogen Idec shall contractually obligate each ZEVALIN
SUBLICENSEE identified in paragraph 4.4 to agree to maintain records sufficient
to audit the calculation of NET SALES by such sublicensee, and to permit audits
in accordance with this paragraph 4.6.

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       10
<PAGE>

            4.7 Dispute Over Payments Under Paragraphs 4.1 And 4.2: In the event
that Corixa, Coulter, Michigan and GSK believe that Biogen Idec has not complied
with its obligations under paragraphs 4.1 or 4.2, they shall provide Biogen Idec
with written notice thereof. This written notice shall provide an explanation of
the nature of the alleged lack of compliance and the actions believed to be
necessary to cure such lack of compliance. Biogen Idec shall have forty-five
(45) days from receipt of such written notice to comply with such notice or to
provide written notice that it disputes the allegation that it is not in
compliance with paragraph 4.1 or 4.2. If Biogen Idec provides written notice
that it disputes the allegation that it is not in compliance with paragraph 4.1
or 4.2, then the PARTIES will have a thirty-day time period to negotiate in good
faith the dispute and attempt to reach a resolution thereof. If the PARTIES are
unable to reach resolution, then the PARTIES shall submit the dispute to a
mediator for non-binding resolution according to the provisions of paragraph 12.

      5. WARRANTIES:

            5.1 Corixa, Coulter, Michigan and GSK warrant that: (i) they [*]
have a [*] interest in THE KAMINSKI PATENT FAMILY and THE WAHL PATENT FAMILY to
grant the licenses set forth in paragraph 3.1 above (including, without
limitation, such that [*] from [*] an [*] in any [*] of THE KAMINSKI PATENT
FAMILY or THE WAHL PATENT FAMILY will be [*] by Biogen Idec, or any assignee or
sublicensee of Biogen Idec hereunder, under THE KAMINSKI PATENT FAMILY or THE
WAHL PATENT FAMILY [*] [*]); and (ii) they have the right to grant the licenses,
with right to sublicense, described in such paragraph 3.1.

            5.2 Biogen Idec warrants that: (i) it has a [*] interest in THE
NEORX PATENT FAMILY to grant the licenses set forth in paragraph 3.2 above
(including, without limitation, such [*] from [*] an [*] in any [*] of THE NEORX
PATENT FAMILY will be [*] for Corixa, Coulter and GSK, or any assignee or
sublicensee of Corixa, Coulter or GSK hereunder, under THE NEORX PATENT FAMILY
[*]); and (ii) it has the right to grant the licenses, with right to sublicense,
described in such paragraph 3.2.

            5.3 The PARTIES hereby warrant to each other that they have not
sold, assigned, transferred, conveyed or otherwise disposed of any claim or
other right or interest inconsistent with this AGREEMENT.

            5.4 Each PARTY shall indemnify and hold the other PARTY(IES), its
AFFILIATES and its and their SUBLICENSEES, harmless against any and all claims,
demands, actions, proceedings, liabilities, losses, damages, costs, and
expenses, including, without limitation, reasonable expert witness and
attorneys' fees and costs arising from or related to any suit or claim by a
THIRD PARTY which is based upon a breach of the representations and warranties
made by the representing PARTY in sections 5.1 to 5.3 above.

      6. NO CHALLENGES TO EACH OTHER'S LICENSED PATENTS:

            6.1 NO CHALLENGES RE KAMINSKI PATENT FAMILY AND WAHL PATENT FAMILY

               6.1.1 Coulter, Corixa, GSK and Michigan hereby each agree that
neither it nor any AFFILIATE or any licensee or sublicensee of THE KAMINSKI
PATENT FAMILY

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       11
<PAGE>

or WAHL PATENT FAMILY will file or prosecute, or encourage or assist directly or
indirectly any THIRD PARTY in filing or prosecuting, any claim, or lawsuit, or
claim, cross-claim or counterclaim for patent infringement of any of THE
KAMINSKI PATENT FAMILY and WAHL PATENT FAMILY against the following persons or
entities: (a) any pharmacy, radiopharmacy or nuclear medicine pharmacy or
facility to the extent it is a recipient of ZEVALIN KITS for preparation and/or
administration to one or more particular patients; (b) any hospital or
governmental health agency to the extent it is a recipient of ZEVALIN KITS for
preparation and/or administration to one or more particular patients; (c) any
physician, nuclear medicine practitioner or licensed health care practitioner to
the extent he or she prescribes, prepares, and/or administers ZEVALIN to one or
more particular patients; (d) any health care insurance company; or (e) Biogen
Idec, its AFFILIATES and any SUBLICENSEES of the foregoing as well as any of
their distributors, importers, exporters, wholesalers, manufacturers and
customers. Subpart (e) of this paragraph 6.1.1 shall be null and void and of no
further force or effect solely with respect to any of Biogen Idec, its
AFFILIATES or any of its SUBLICENSEES that breach any provisions of this Section
6.

               6.1.2 Biogen Idec agrees that neither it nor any AFFILIATE will
initiate or prosecute, or encourage or assist directly or indirectly any THIRD
PARTY in initiating or prosecuting, any claim, or lawsuit, or claim, cross-claim
or counterclaim in any lawsuit, or any administrative proceeding (including
without limitation any proceeding with the United States Patent and Trademark
Office or its counterpart agency in any other country) challenging the validity,
inventorship or enforceability of THE KAMINSKI PATENT FAMILY and WAHL PATENT
FAMILY, except as required by law (e.g., such as responding to subpoena for
documents or testimony). As to THE KAMINSKI PATENT FAMILY and THE WAHL PATENT
FAMILY, Biogen Idec, its AFFILIATES, and any SUBLICENSEE hereunder (but solely
for the duration of their sublicense, as provided in paragraph 6.1.3), waive any
and all invalidity, inventorship and unenforceability defenses in any future
litigation, arbitration, or other legal or administrative proceeding; provided,
however, that nothing in this paragraph prevents Biogen Idec or its AFFILIATES
or its SUBLICENSEES from:

                  (i) challenging the validity, enforceability, inventorship or
      scope of [*] of U.S. Patent No. [*] and any patent claim not issued in THE
      KAMINSKI PATENT FAMILY and WAHL PATENT FAMILY as of the date of this
      Agreement in the context of Biogen Idec or its AFFILIATES or its
      SUBLICENSEES', as applicable, filing, prosecuting, defending or enforcing
      (including but not limited to, the conduct of any interferences including
      those conducted in the Patent and Trademark Office and actions brought
      under 35 U.S.C. Section 146 and Section 291, reexaminations, reissues,
      oppositions, or requests for patent term extensions relating thereto) any
      intellectual property rights that the applicable entity owns or controls
      (other than THE KAMINSKI PATENT FAMILY and WAHL PATENT FAMILY), except
      that in the context of any enforceability challenge, Biogen Idec, its
      AFFILIATES and, subject to paragraph 6.1.3, its SUBLICENSEES expressly
      waive the right to raise, assert, use or rely on any acts that occurred
      before the date of this Agreement;

                  (ii) asserting any and all defenses available to Biogen Idec,
      its AFFILIATES and its SUBLICENSEES in any suit or claim brought by a
      THIRD PARTY against them, including, without limitation, assertions
      relating to the validity,

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       12
<PAGE>

      enforceability, inventorship or scope of any patent in THE KAMINSKI PATENT
      FAMILY and WAHL PATENT FAMILY; and

                  (iii) asserting any and all defenses available to Biogen Idec,
      its AFFILIATES and its SUBLICENSEES in any suit brought against them or
      their SUBLICENSEES, distributors, importers, exporters, wholesalers,
      manufacturers, or customers for patent infringement of any patent of THE
      KAMINSKI PATENT FAMILY or WAHL PATENT FAMILY, including, without
      limitation, assertions relating to the validity, enforceability,
      inventorship or scope of any patent in THE KAMINSKI PATENT FAMILY and WAHL
      PATENT FAMILY.

               6.1.3 Biogen Idec agrees that, if it grants any sublicense to THE
KAMINSKI PATENT FAMILY and WAHL PATENT FAMILY as permitted under paragraph 3.1.3
of this AGREEMENT, such sublicense will include an obligation on the part of the
intended SUBLICENSEE to be bound by paragraph 6.1.2 for the duration of such
sublicense, provided however, that such intended SUBLICENSEE may have the right
to terminate the sublicense and thereafter be no longer bound by paragraph
6.1.2.

               6.1.4 Corixa, Coulter, Michigan and GSK each agree that, if it
grants any sublicense to THE KAMINSKI PATENT FAMILY and WAHL PATENT FAMILY after
the EFFECTIVE DATE of this AGREEMENT, such sublicense will include an obligation
on the part of such intended SUBLICENSEE to be bound by paragraph 6.1.1 for the
duration of such sublicense.

            6.2 NO CHALLENGES RE NEORX PATENT FAMILY

               6.2.1 Biogen Idec hereby agrees that neither it nor any AFFILIATE
or any licensee or sublicensee of THE NEORX PATENT FAMILY will file or
prosecute, or encourage or assist directly or indirectly any THIRD PARTY in
filing or prosecuting, any claim, or lawsuit, or claim, cross-claim or
counterclaim for patent infringement of any of THE NEORX PATENT FAMILY against
the following persons or entities: (a) any pharmacy, radiopharmacy or nuclear
medicine pharmacy or facility to the extent it is a recipient of BEXXAR for
preparation and/or administration to one or more particular patients; (b) any
hospital or governmental health agency to the extent it is a recipient of BEXXAR
for preparation and/or administration to one or more particular patients; (c)
any physician, nuclear medicine practitioner or licensed health care
practitioner to the extent he or she prescribes, prepares, and/or administers
BEXXAR to one or more particular patients; (d) any health care insurance
company; and (e) Corixa, Coulter, GSK, their AFFILIATES and any SUBLICENSEES of
the foregoing as well as any of their distributors, importers, exporters,
wholesalers, manufacturers, or customers. Subpart (e) of this paragraph 6.2.1
shall be null and void and of no further force or effect solely with respect to
any of Corixa, Coulter, GSK, their AFFILIATES or any of their SUBLICENSEES that
breach any provisions of this Section 6.

               6.2.2 Corixa, Coulter, and GSK each agree that neither they nor
any AFFILIATE will initiate or prosecute, or encourage or assist directly or
indirectly any THIRD PARTY in initiating or prosecuting, any claim, or lawsuit,
or claim, cross-claim or counterclaim in any lawsuit, or any administrative
proceeding (including without limitation any proceeding

                                       13
<PAGE>

with the United States Patent and Trademark Office or its counterpart agency in
any other country) challenging the validity, inventorship or enforceability of
THE NEORX PATENT FAMILY, except as required by law (e.g., such as responding to
subpoena for documents or testimony). As to THE NEORX PATENT FAMILY, Corixa,
Coulter and GSK, its AFFILIATES, and any SUBLICENSEE hereunder (but solely for
the duration of their sublicense, as provided in paragraph 6.2.3), waive any and
all invalidity, inventorship and unenforceability defenses in any future
litigation, arbitration, or other legal or administrative proceeding; provided,
however, that nothing in this paragraph prevents Corixa, Coulter and GSK or
their AFFILIATES or SUBLICENSEES; and provided, however, that nothing in this
paragraph prevents Corixa, Coulter, and GSK or their AFFILIATES or SUBLICENSEES
from:

                  (i) challenging the validity, enforceability, inventorship or
      scope of any patent claim in THE NEORX PATENT FAMILY in the context of
      Corixa, Coulter, and GSK or any of their AFFILIATES or their
      SUBLICENSEES's, as applicable, filing, prosecuting, defending or enforcing
      (including but not limited to, the conduct of any interferences including
      those conducted in the Patent and Trademark Office and actions brought
      under 35 U.S.C. Section 146 and Section 291, reexaminations, reissues,
      oppositions, or requests for patent term extensions relating thereto) any
      intellectual property rights that the applicable entity owns or controls
      (other than THE NEORX PATENT FAMILY), except that in the context of any
      enforceability challenge, Corixa, Coulter and GSK, their AFFILIATES and,
      subject to paragraph 6.2.3, their SUBLICENSEES expressly waive the right
      to raise, assert, use or rely on any acts that occurred before the date of
      this Agreement;

                  (ii) asserting any and all defenses available to Corixa,
      Coulter, and GSK and any of their AFFILIATES and SUBLICENSEES in any suit
      or claim brought by a THIRD PARTY against them, including, without
      limitation, assertions relating to the validity, enforceability,
      inventorship or scope of any patent in THE NEORX PATENT FAMILY; and

                  (iii) asserting any and all defenses available to Corixa,
      Coulter, and GSK and any of their AFFILIATES and SUBLICENSEES in any suit
      brought against them or their SUBLICENSEES, distributors, importers,
      exporters, wholesalers, manufacturers, or customers for patent
      infringement of any patent of THE NEORX PATENT FAMILY, including, without
      limitation, assertions relating to the validity, enforceability,
      inventorship or scope of any patent in THE NEORX PATENT FAMILY.

               6.2.3 Corixa, Coulter and GSK each agree that, if they grant any
sublicense to THE NEORX PATENT FAMILY as permitted under paragraph 3.2.3 of this
AGREEMENT, such sublicense will include an obligation on the part of the
intended SUBLICENSEE to be bound by paragraph 6.2.2 for the duration of such
sublicense, provided however, that such intended sublicensee may have the right
to terminate the sublicense and thereafter be no longer bound by paragraph
6.2.2.

               6.2.4 Biogen Idec agrees that, if it grants any sublicense to THE
NEORX PATENT FAMILY after the EFFECTIVE DATE of this AGREEMENT, such

                                       14
<PAGE>

sublicense will include an obligation on the part of such intended sublicensee
to be bound by paragraph 6.2.1 for the duration of such sublicense.

      7. RELEASES:

            7.1 Corixa, Coulter, Michigan and GSK, for themselves and their
agents, successors, assigns, employees, representatives and attorneys, hereby
release and discharge Biogen Idec and its respective present or former officers,
directors, stockholders, employees, agents, AFFILIATES, partners, predecessors,
successors, heirs, executors, assigns and attorneys from any and all claims,
demands, actions, rights, causes of action, debts, obligations, costs, expenses,
attorneys' fees, damages, and liabilities of any kind or nature or character
whatsoever whether known or unknown, suspected or unsuspected, actual or
potential, absolute or contingent, pending or anticipated, which relate to any
and all allegations or claims of infringement of any patents of THE KAMINSKI
PATENT FAMILY and THE WAHL PATENT FAMILY with respect to any acts committed
prior to the EFFECTIVE DATE of this AGREEMENT, any and all claims that were or
could have been made in THE LAWSUITS, any and all claims which arise out of or
are connected to any occurrence or conduct alleged or referred in THE LAWSUITS
which occurred prior to the EFFECTIVE DATE of this AGREEMENT, and any and all
claims which arise out of or are connected to the filing, prosecution, and
defense of THE LAWSUITS.

            7.2 Biogen Idec, for itself and its agents, successors, assigns,
employees, representatives and attorneys, hereby releases and discharges Corixa,
Coulter, Michigan and GSK and their respective present or former officers,
directors, stockholders, employees, agents, AFFILIATES, partners, predecessors,
successors, heirs, executors, assigns and attorneys from any and all claims,
demands, actions, rights, causes of action, debts, obligations, costs, expenses,
attorneys' fees, damages, and liabilities of any kind or nature or character
whatsoever whether known or unknown, suspected or unsuspected, actual or
potential, absolute or contingent, pending or anticipated, which relate to any
and all allegations and claims of infringement of any patents of THE NEORX
PATENT FAMILY with respect to any acts committed prior to the EFFECTIVE DATE of
this AGREEMENT, any and all claims that were or could have been made in THE
LAWSUITS, any and all claims which arise out of or are connected to any
occurrence or conduct alleged or referred in THE LAWSUITS which occurred prior
to the EFFECTIVE DATE of this AGREEMENT, and any and all claims which arise out
of or are connected to the filing, prosecution, and defense of THE LAWSUITS.

            7.3 It is specifically understood that this AGREEMENT may be pleaded
as a full and complete defense to, and may be used as a basis for an injunction
against any action, suit, or other proceeding, which may be instituted,
prosecuted, or attempted in breach of this AGREEMENT.

      8. WAIVER OF CIVIL CODE 1542: The PARTIES specifically understand,
acknowledge and agree that this is a full and final release, applying to any and
all of the claims released in paragraphs 7.1 and 7.2 , whether known or unknown.
The PARTIES, having been fully advised by their respective counsel, hereby
expressly waive the benefit of the provisions of Section 1542 of the Civil Code
of the State of California, which provides as follows, and under all federal,
state and common-law statutes or principles of similar effect:

                                       15
<PAGE>

                  A general release does not extend to claims which the creditor
            does not know or suspect to exist in his favor at the time of
            executing the release, which if known by him must have materially
            affected his settlement with the debtor.

      9. NO OTHER LICENSES:

            9.1 The licenses granted hereunder are limited to those patent
families specifically identified. Nothing in this AGREEMENT or the course of
dealings between the PARTIES or usage or custom in the industry or trade shall
be construed to confer any other rights or licenses to any other patents by
implication, estoppel or otherwise.

            9.2 Without limitation of the foregoing, this AGREEMENT does not
grant any license under any patents (including U.S. Patent No. [*]) issuing from
the application for United States Letter Patent Serial No. [*], filed [*], for
the invention titled "[*]."

            9.3 Furthermore, Biogen IDEC agrees that it has released and shall
never assert any claim or defense of an implied license under any theory or
course of dealing, including under [*] agreement between [*] and [*], to any of
the patents in THE KAMINSKI PATENT FAMILY in connection with any patents
(including U.S. Patent No. [*]) issuing from the application for [*], filed [*],
for the invention titled "[*]."

      10. ASSIGNMENTS OF RIGHTS:

            10.1 Biogen Idec may not assign or transfer its rights and
obligations under this AGREEMENT to a non-AFFILIATE that does not purchase
substantially all of Biogen Idec's rights associated with ZEVALIN(R) without
each of Corixa, Coulter, Michigan and GSK's consent, which shall not be
unreasonably withheld. The failure to respond in writing to a written request
for consent within 30 days shall be deemed to be consent. Each of Corixa,
Coulter, Michigan and GSK may not assign or transfer its rights and obligations
under this AGREEMENT to a non-AFFILIATE that does not purchase substantially all
of their rights associated with BEXXAR(R) without Biogen Idec's consent, which
shall not be unreasonably withheld. The failure to respond in writing to a
written request for consent within 30 days shall be deemed to be consent. Such
assignments or transfers shall include in writing terms and conditions
sufficient to obligate such assignee or transferee to comply with the assignor's
obligations under this AGREEMENT. In all instances, the following obligations
shall remain binding upon the initial PARTIES notwithstanding any assignment or
transfer: paragraphs 1, 5.4, 6, 7, 8, 9, 12, 14 and 15. Except as provided
otherwise in this paragraph, in the event of any assignment or transfer, the
assignor's obligations will be passed on to the assignee without further
recourse to the assignor.

            10.2 Biogen Idec may assign or otherwise transfer part or all of the
rights, title or interest to THE NEORX PATENT FAMILY, provided that any such
assignment or transfer includes terms and conditions sufficient to obligate any
such assignee or transferee to comply with Biogen Idec's obligations under this
AGREEMENT with respect to THE NEORX PATENT FAMILY, including, without
limitation, (i) an acknowledgement of the licenses

                                               *CONFIDENTIAL TREATMENT REQUESTED

                                       16
<PAGE>

granted under paragraph 3.2 above and (ii) agreement to the covenant not to sue
set forth in paragraph 6.2.1 above.

            10.3 Biogen Idec may assign or otherwise transfer part or all of the
rights, title or interest to the ZEVALIN KITS, provided that any such assignment
or transfer includes terms and conditions sufficient to obligate any such
assignee or transferee to comply with Biogen Idec's obligations under this
AGREEMENT with respect to the ZEVALIN KITS, including, without limitation,
agreement to make the reports and to pay the amounts set forth in paragraph 4
above.

            10.4 Biogen Idec may assign or transfer its rights and obligations
under this AGREEMENT to an AFFILIATE that does not purchase substantially all of
Biogen Idec's rights associated with ZEVALIN(R), provided that Biogen Idec
remains responsible for the performance by the assignee of its obligations under
this AGREEMENT.

            10.5 Coulter, Corixa, Michigan and GSK may assign or otherwise
transfer part or all of the rights, title or interest to THE KAMINSKI PATENT
FAMILY and THE WAHL PATENT FAMILY, provided that any such assignment or transfer
includes terms and conditions sufficient to obligate any such assignee or
transferee to comply with the obligations of Coulter, Corixa, Michigan and GSK
under this AGREEMENT with respect to THE KAMINSKI PATENT FAMILY and THE WAHL
PATENT FAMILY, including, without limitation, (i) an acknowledgement of the
licenses granted under paragraph 3.1 above and (ii) agreement to the covenant
set not to sue forth in paragraphs 6.1.1 above.

      11. TERM: This AGREEMENT shall come into force as of the EFFECTIVE DATE
and shall continue in full force and effect, until the expiration of the last to
expire of any of THE KAMINSKI PATENT FAMILY, WAHL PATENT FAMILY or NEORX PATENT
FAMILY, except that paragraphs 4 and 12 of this AGREEMENT, and all other
provisions necessary to interpret and give effect to paragraph 4, shall remain
in full force and effect until all milestone payments and royalties that accrued
under paragraph 4 prior to the expiration of such patents have been paid and any
related disputes have been resolved, and except that the confidentiality
provisions of paragraph 15 shall remain in full force and effect without
expiration.

      12. AGREEMENT TO MEDIATE DISPUTES OR CLAIMS ARISING FROM AGREEMENT: If a
dispute arises out of or relates to this AGREEMENT, or the breach thereof, the
Parties agree to first attempt to resolve the dispute through negotiation. If
the dispute cannot be settled through negotiation, the PARTIES agree to next try
in good faith to settle the dispute by mediation before resorting to
arbitration, litigation, or some other dispute resolution procedure.
Notwithstanding this paragraph 12, any PARTY may commence and pursue litigation
or administrative remedies with respect to disputes arising out of or relating
to this AGREEMENT (i) ninety (90) days following an initial written notice of
such dispute to the other PARTIES or (ii) at any time, in the event that a PARTY
files in a court of competent jurisdiction a motion for temporary restraining
order, preliminary injunction or similar equitable relief which solely involve
paragraphs 6 or 15 of this AGREEMENT.

                                       17
<PAGE>

      13. NOTICES: Any notice, request, approval or other document required or
permitted to be given under this AGREEMENT shall be in written and shall be
delivered by an overnight courier service (such as Federal Express) or by
certified or registered mail, return receipt requested, addressed as follows, or
to such other address or fax number as the PARTY may have subsequently
designated by written notice to all other PARTIES:

                                       18
<PAGE>

                  13.1     If to Biogen Idec:

                           Biogen Idec Inc.
                           14 Cambridge Center
                           Cambridge, MA 02142
                           Attention:  General Counsel
                           Fax No.:  617-679-2838

                  13.2     If to Corixa or Coulter:

                           Corixa Corporation
                           1124 Columbia Street, Suite 200
                           Seattle WA    98104
                           Attention:  General Counsel
                           Fax No.:  206-754-5994
                           Coulter Corporation
                           c/o Corixa Corporation
                           [At the same address and fax number as above]

                  13.3     If to Michigan:

                           Director of Licensing
                           Attention:       File 1009
                           University of Michigan
                           Office of Technology Transfer
                           2071 Wolverine Tower
                           3003 S. State Street
                           Ann Arbor, MI    48109-1280
                           Fax No.:   734-936-1330

                  13.4     If to GSK:

                           SmithKline Beecham Corporation,
                           doing business as GlaxoSmithKline
                           Corporate Law Department
                           One Franklin Plaza
                           20 N. 16th Street
                           Philadelphia, PA   19006
                           Attention:  Senior Vice President & General Counsel
                           Fax No.:   610-270-5713

      14. COSTS AND FEES: Each PARTY shall bear its own costs, attorneys' fees
and other expenses, incurred in connection with THE LAWSUITS and this AGREEMENT.

      15. CONFIDENTIALITY:

            15.1 This AGREEMENT, and all its terms, shall be maintained in
confidence by the PARTIES, provided that any PARTY may make such disclosures
required by law,

                                       19
<PAGE>

including financial or corporate reporting obligations. Notwithstanding the
foregoing, each PARTY may state the existence and amount of the upfront payment
in their financial reports, and may state that THE LAWSUITS between the PARTIES
have settled with the payment by Biogen Idec of an upfront settlement payment, a
sales-based milestone payment, and a royalty payment on United States sales of
ZEVALIN(R) KITS. Each PARTY may disclose, and provide copies of, this AGREEMENT
and its terms to AFFILIATES and financial, accounting, tax and securities law
advisors, who shall each agree to identical nondisclosure obligations as set
forth in this section 15. Furthermore, notwithstanding the foregoing, a PARTY
may disclose the terms of this Agreement to an actual or potential AFFILIATE,
SUBLICENSEE or a potential acquirer of a PARTY or certain of its assets
including those subject to this AGREEMENT, as reasonably necessary to the
conduct of the PARTY's business, provided that such disclosure is accompanied by
an agreement obligating the party receiving the information to keep the
information confidential. Michigan may disclose the financial terms of this
AGREEMENT to its inventors of THE KAMINSKI PATENT FAMILY, who shall each agree
in writing to identical nondisclosure obligations as set forth in this paragraph
15.

            15.2 In the event that a PARTY is served with a legal document
demanding the production or disclosure of this AGREEMENT or the terms or
provisions of this AGREEMENT, such Party shall give notice of the same to the
other PARTIES as soon as practicable and in any event shall not produce or
disclose the terms of this AGREEMENT until the other PARTIES have received
notice and have had an opportunity to oppose the demand if appropriate. In the
event that a PARTY is advised in good faith by legal counsel that disclosure of
any of the terms or provisions of this AGREEMENT is required pursuant to the
reporting requirements of any law (including but not limited to the reporting
requirements of the Securities Exchange Commission or related law or regulations
or comparable laws or regulations in a foreign country), then such PARTY shall
provide notice of the intended public disclosure (including the precise language
of the disclosure) to the other undersigned PARTIES at least 48 hours before
making such disclosure. The Protective Order entered in the Lawsuits shall
survive dismissal and be complied with by the PARTIES per its terms.

      16. SUCCESSORS: This AGREEMENT shall inure to the benefit of and be
binding upon the PARTIES' respective successors and assigns.

      17. COUNTERPARTS: This AGREEMENT may be executed in several counterparts,
and shall be effective when so executed by all PARTIES identified below and
thereupon shall constitute one agreement, binding on all PARTIES hereto,
notwithstanding that all PARTIES are not signatory to the original or the same
counterpart.

      18. FINAL EXPRESSION OF AGREEMENT: Except for the `827 COVENANT NOT TO SUE
and the Settlement and License Agreement entered into between SmithKline Beecham
Corporation and Idec Pharmaceuticals Corporation dated November 14, 2002, this
AGREEMENT and all associated papers represent and contain the entire agreements
among the PARTIES with respect to the subject matter of this AGREEMENT, and
supersedes any and all prior or contemporaneous oral and written negotiations,
agreements and understandings, including the Memorandum of Agreement dated
February 27, 2004. No representation, warranty, condition, understanding or
agreement of any kind with respect to the subject matter hereof shall be relied
upon by the PARTIES except those expressly contained herein. This

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<PAGE>

AGREEMENT may not be amended or modified or waived except as agreed in writing
by all PARTIES.

      19. PORTION VOID: Should any word, clause, phrase, or portion of this
AGREEMENT be judicially declared to be to any extent void or unenforceable, such
portion shall be construed as if it were written so as to effectuate, to the
maximum extent possible and enforceable, the PARTIES' intent, and in any event
such portion shall be considered independent and severable from the remainder of
the AGREEMENT, the validity of which shall remain unaffected.

      20. DRAFTED BY THE PARTIES: In the event of a dispute, this AGREEMENT
shall be interpreted in accordance with its fair meaning and shall not be
interpreted for or against any PARTY hereto on the ground that such PARTY
drafted or caused to be drafted this AGREEMENT or any part thereof. Accordingly,
the PARTIES agree that the normal rule of construction to the effect that any
ambiguities are to be resolved against the drafting PARTY shall not be employed
in the interpretation of this AGREEMENT.

      21. GOVERNING LAW: This AGREEMENT is made pursuant to, and shall be
governed by, the internal laws of the State of California. The PARTIES agree
that this AGREEMENT shall be enforceable in any court of competent jurisdiction
within the State of California.

      22. ADVICE OF COUNSEL: The PARTIES hereto acknowledge that they have each
consulted, conferred with, and obtained the advice of their respective legal
counsel, prior to executing this AGREEMENT; that they have entered into and
executed this AGREEMENT voluntarily and with full knowledge and appreciation of
the meaning, scope, effect and significance of each and every provision
contained herein; and that they do not rely and have not relied upon any
representation or statement made by any other PARTY or any of their
representatives or attorneys with regard to the subject matter, consideration,
scope, basis or effect and significance of this AGREEMENT.

      23. NO ADMISSION OF LIABILITY: It is understood and agreed that this
AGREEMENT is a compromise of disputed claims and that the offer and acceptance
of consideration by the PARTIES is not to be construed as admission of liability
by any PARTY, which liability is expressly denied.

      24. KNOWING AND VOLUNTARY EXECUTION: The PARTIES hereto, and each of them,
further represent and declare that they have carefully read this AGREEMENT and
know the contents thereof and that they sign the same freely and voluntarily.

                                       21
<PAGE>

      IN WITNESS WHEREOF the PARTIES have executed this AGREEMENT on the dates
indicated below. The signatories below represent that they have the authority to
sign for the entity for which they sign and that their signature is binding upon
that entity.

BIOGEN IDEC INC.                        CORIXA CORPORATION

By: /s/ William R. Rohn                 By: /s/ Kathleen McKereghan
    ------------------------                ------------------------------------
Its: Chief Operating Officer            Its: Sr. VP, General Counsel & Secretary
Dated: May 7, 2004                      Dated: May 7, 2004

COULTER PHARMACEUTICAL INC.             SMITHKLINE BEECHAM CORPORATION,
                                        d/b/a GlaxoSmithKline

By: /s/ Kathleen McKereghan             By: /s/ Ronald Parman
    ------------------------                ------------------------------------
Its: Secretary                          Its: Vice President and Secretary
Dated: May 7, 2004                      Dated: May 7, 2004

REGENTS OF THE UNIVERSITY OF MICHIGAN

By: /s/ Kenneth J. Nisbet
--------------------------------------
Its: Executive Director, UM Technology
      Transfer

Dated: May 6, 2004

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