<PAGE>
                                                                   EXHIBIT 10.1

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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.
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              DEVELOPMENT, COMMERCIALIZATION AND LICENSE AGREEMENT

        This DEVELOPMENT, COMMERCIALIZATION AND LICENSE AGREEMENT (the
"Agreement") is entered into on October 26, 2001 (the "Signing Date") and made
effective as of the Effective Date (as defined below) between CORIXA
CORPORATION, a Delaware corporation, with its principal place of business at
1124 Columbia Street, Suite 200, Seattle, WA 98104, U.S.A. ("Corixa
Corporation"), and AMERSHAM PLC, a company incorporated under the laws of
England, with its principal place of business at Amersham Place, Little
Chalfont, Buckinghamshire, England HP7 9NA ("Amersham"). Both Corixa and
Amersham are referred to individually as a "Party" and collectively as the
"Parties."

        WHEREAS, Corixa, as the successor to Coulter Pharmaceutical, Inc.
("Coulter"), has rights to and is developing Bexxar, an antibody product pending
FDA approval; and

        WHEREAS, Amersham possesses development, manufacturing, marketing and
distribution capability for radiolabeled products in Europe; and

        WHEREAS, Amersham desires to obtain rights to develop and commercialize
such product in Europe for the treatment of humans and Corixa is willing to
grant such rights on the terms and conditions hereof; and

        WHEREAS, Amersham desires to obtain bulk or finished antibody for such
product from Corixa and Corixa is willing to provide such antibody on the terms
and conditions as set forth in the supply agreement by and between the Parties
of even date herewith (the "Supply Agreement"); and

        NOW THEREFORE, in consideration of the foregoing premises and the mutual
promises, covenants and conditions contained in this Agreement, the Parties
agree as follows:

1.      DEFINITIONS

        The following terms shall have the following meanings as used in this
Agreement:

        1.1 "AFFILIATE" means, with respect to a particular Party, a person,
corporation, partnership, or other entity that controls, is controlled by or is
under common control with such Party. For the purposes of the definition in this
Section 1.1, the word "control" (including, with correlative meaning, the terms
"controlled by" or "under the common control with") means the actual power,
either directly or indirectly through one or more intermediaries, to direct or
cause the direction of the management and policies of such entity, whether by
the ownership of at least fifty percent (50%) of the voting stock of such
entity, or by contract or otherwise. Anything to the contrary, notwithstanding,
the term "Affiliate" shall not include Nihon Medi-Physics, Inc., a Japanese
company.

        1.2 "AMERSHAM IODINE I 131 TOSITUMOMAB" shall mean any Iodine I 131
Tositumomab that Amersham or its agent prepares from Tositumomab.



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        1.3 "AMERSHAM MATTER" shall mean any issue relating to:

            (a) development (including without limitation clinical development
and Regulatory Filings) of the Product for and in the Territory other than those
issues related to obtaining Initial Approval;

            (b) the European Facility or the manufacture of the Amersham Iodine
I 131 Tositumomab in the Territory; or

            (c) sale and/or marketing of the Product in the Territory.

        1.4 "ANNUAL NET SALES" shall mean, with respect to a particular calendar
year, the total Net Sales for such calendar year.

        1.5 "BLA" shall mean a Biologics License Application, as defined by the
regulations promulgated under the United States FD&C Act and Public Health
Services Act and any supplements thereunder, as amended from time to time.

        1.6 "CLINICAL TRIAL" shall mean a trial, conducted by a Party or a
licensee of a Party, in which a Product is administered to humans with the goal
of generating data (a) to support an application for Regulatory Approval of such
Product or (b) for purposes of marketing the Product. The Clinical Trials
initiated or planned by Corixa prior to the Effective Date are listed in Exhibit
D.

        1.7 "CLINICAL TRIAL COSTS" shall mean the direct and indirect costs
incurred by one or both Parties and any licensees thereof in connection with a
particular Clinical Trial, including, without limitation, fees paid to clinical
sites, fees paid to human subjects participating in such Clinical Trial, and FTE
and other overhead expenses, if any, directly attributable to such Clinical
Trial.

        1.8 "COLLABORATION STEERING COMMITTEE" and "CSC" shall have the meanings
given such terms in Section 3.1(a).

        1.9 "CONTROLLED" means, with respect to any gene, protein, compound,
material, Information or intellectual property right, that the Party owns or has
a license to such gene, protein, compound, material, Information or intellectual
property right and has the ability to grant to the other Party access, a license
or a sublicense (as applicable) to such gene, protein, compound, material,
Information or intellectual property right on the terms and conditions set forth
herein without violating the terms of any agreement or other arrangements with
any Third Party existing at the time such Party would be first required
hereunder to grant the other Party such access, license or sublicense.

        1.10 "CORIXA" shall mean Corixa Corporation and its Affiliates.

        1.11 "CORIXA INTELLECTUAL PROPERTY RIGHTS" shall mean all Intellectual
Property Rights in existence on the Effective Date that are Controlled by Corixa
during the term of this Agreement, including those Patents set forth in Exhibit
A (which Corixa may update from time to time).



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        1.12 "CORIXA IODINE I 131 TOSITUMOMAB" shall mean any Iodine I 131
Tositumomab that Corixa provides to Amersham hereunder.

        1.13 "CORIXA MATTER" shall mean any issue relating to (a) obtaining
Initial Approval (including without limitation clinical development and
Regulatory Filings) or (b) manufacture (except for those issues relating solely
to the European Facility) of the Product for use in the Territory. For clarity,
all issues concerning whether a particular Clinical Trial shall be designated as
an Initial Approval Clinical Trial pursuant to Section 4.5 or 5.4 are Corixa
Matters.

        1.14 "CORIXA TERRITORY" shall mean all countries and territories of the
world except those in the Territory.

        1.15 "CROSS-TERRITORY CLINICAL TRIAL" shall mean a Clinical Trial
conducted in the Territory and the Corixa Territory.

        1.16 "DANA FARBER AGREEMENTS" shall mean:

             (a) the Agreement between Sidney Farber Cancer Institute and
Coulter Electronics, Inc., dated July 23, 1981;

             (b) Modification Agreement between Dana-Farber Cancer Institute and
Coulter Electronics, Inc., dated March 1, 1983;

             (c) License Agreement between Dana-Farber Cancer Institute and
Coulter Immunology, Division of Coulter Corporation, dated April 28, 1983;

             (d) Modification Agreement No. 2 between Dana-Farber Cancer
Institute and Coulter Immunology, Division of Coulter Corporation, dated April
1, 1987;

             (e) Agreement between Coulter Corporation and Dana-Farber Cancer
Institute, Inc., dated April 1, 1994;

             (f) Agreement between Coulter Pharmaceutical and Coulter
Corporation, dated February 24, 1995; and

             (g) Agreement among Dana-Farber Cancer Institute, Coulter
Corporation and Coulter Pharmaceutical, Inc. dated December 2, 1998.

        1.17 "DEVELOPMENT BUDGET" shall mean the detailed budget for the
activities described in the Development Plan (whether the Initial Development
Plan or the Subsequent Development Plan), approved as a part of the Initial
Development Plan or Subsequent Development Plan, as applicable, pursuant to
Section 4.2, 4.3 or 4.4.

        1.18 "DEVELOPMENT PLAN" shall mean the Initial Development Plan or the
Subsequent Development Plan, as the context indicates.

        1.19 "DILIGENT EFFORTS" means the carrying out of obligations or tasks
in a sustained manner consistent with the efforts a Party devotes to a product
or a development or marketing



                                       3.
<PAGE>

project of similar market potential, profit potential or strategic value
resulting from its own efforts, based on conditions then prevailing.

        1.20 "EFFECTIVE DATE" shall mean the First Closing Date, as such term is
defined in the Stock Purchase Agreement.

        1.21 "EUROPEAN FACILITY" shall have the meaning set forth in the Supply
Agreement.

        1.22 "FD&C ACT" shall mean the United States Federal Food, Drug and
Cosmetic Act, as amended.

        1.23 "FDA" shall mean the United States Food and Drug Administration or
its successor.

        1.24 "FIELD" shall mean the treatment, prevention or palliation of any
indication in humans. In no event shall "Field" include diagnosis of such
indications.

        1.25 "FIRST COMMERCIAL SALE" shall mean the first commercial sale of a
Product in a given regulatory jurisdiction after the Product has been granted
Regulatory Approval by the competent authorities in such jurisdiction.

        1.26 "FTE RATE" shall mean the amount to be paid by Amersham for
consulting services rendered by the Corixa's employees. The FTE Rate for
calendar year 2001 will be the lesser of: (a) [*] dollars ($[*]) per hour or (b)
[*] dollars ($[*]) per day per employee. For each subsequent calendar year, this
rate will be adjusted by the percentage change in the monthly Consumer Price
Index for the immediately preceding October as compared to the base month of
October, 2000. The index source will be the Consumer Price Index published by
the Bureau of Labor Statistics of the United States Department of Labor and
covering San Francisco, California, Seattle, Washington and Missoula, Montana.
Should indices covering all of the foregoing areas not be available, then the
national index will be used as the reference.

        1.27 "FULLY ALLOCATED COST" shall mean the direct and indirect costs of
Tositumomab provided by Corixa to Amersham or Corixa Iodine I 131 Tositumomab
and shall be computed in accordance with United States generally accepted
accounting principles, consistently applied. To the extent that any such costs
arise from activities performed for Amersham as well as other Corixa partners
for the Product, the amounts allocated to Amersham shall be a fair, pro rata
allocation based upon the performance for Amersham relative to the performance
for other Corixa partners for the Product. Fully Allocated Cost shall include
without limitation:

             (a) cost and expenses incurred by Corixa, including, but not
limited to, payments owed by [*]), for the manufacture or supply to Amersham of
such Tositumomab or Corixa Iodine I 131 Tositumomab, including, but not limited
to, the [*], [*] payments (limited to [*]), payments related to [*] (to the
extent not otherwise [*] pursuant to this Agreement), [*] payments, and [*] owed
to such Third Parties, plus


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             (b) [*] Costs, plus

             (c) If applicable, the cost of forward foreign currency contracts
to protect against risk of changes in foreign exchange rates, provided that such
costs are approved in advance by the Parties, plus

             (d) Corixa's internal and external expenses, including
out-of-pocket expenses and employee expenses, if any, with respect to [*]
associated with [*] Tositumomab or Corixa Iodine I 131 Tositumomab [*], plus

             (e) The cost of [*] in Tositumomab or Corixa Iodine I 131
Tositumomab [*] activities, including, without limitation, [*], plus

             (f) A reasonable allocation, with respect to such Tositumomab or
Corixa Iodine I 131 Tositumomab, of Corixa's: (i) [*] (to the extent not
previously included in (d) or (e)), (ii) [*] costs, and (iii) [*] costs
including [*]. Such allocations shall be in accordance with reasonable cost
accounting methods, consistently applied, of Corixa.

        1.28 "GOOD MANUFACTURING PRACTICE" or "GMP" shall mean the current
standards for the manufacture of pharmaceuticals, as set forth in the FD&C Act
and applicable regulations and guidances promulgated thereunder, including
without limitation the Code of Federal Regulations, as amended from time to
time, and any other applicable manufacturing requirements under the laws, rules
or regulations of the Territory.

        1.29 "INFORMATION" means information, results and data of any type
whatsoever, in any tangible or intangible form whatsoever, including without
limitation, databases, inventions, practices, methods, techniques,
specifications, formulations, formulae, knowledge, know-how, skill, experience,
test data including pharmacological, biological, chemical, biochemical,
toxicological and clinical test data, analytical and quality control data,
stability data, studies and procedures, and patent and other legal information
or descriptions.

        1.30 "INITIAL APPROVAL" shall mean the first approval of an MAA for the
Product by the EMEA.

        1.31 "INITIAL APPROVAL CLINICAL TRIALS" shall mean the Clinical Trials
that the CSC designates pursuant to Section 4.5 or 5.4 as the Clinical Trials
that the Parties expect to be used to seek Initial Approval.

        1.32 "INITIAL APPROVAL TRIAL COSTS" shall mean, with respect to the
Initial Approval Clinical Trials and the Initial Regulatory Filings:

             (a) the direct and indirect costs incurred by Corixa and its Third
Party contractors, including contract research organizations (CRO's), and
consultants in connection with such Clinical Trials and the Initial Regulatory
Filings, including, without limitation, the costs of all Tositumomab and Corixa
Iodine I 131 Tositumomab purchased by Corixa for use in such Clinical Trials,
fees paid to clinical sites for such Clinical Trial, fees paid to human subjects
participating in such Clinical Trials, and FTE and other overhead expenses, if
any, directly attributable to such Clinical Trials or the Initial Regulatory
Filings;

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                                       5.
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             (b) the direct and indirect external costs agreed to in writing by
Corixa and incurred by Amersham and its Third Party contractors and consultants
in connection with such Clinical Trials (including, without limitation, fees
paid to clinical sites for such Clinical Trials and fees paid to human subjects
participating in such Clinical Trials) and the Initial Regulatory Filings; and

             (c) the [*] costs incurred by Amersham pursuant the Section 4.1 or
otherwise as provided under this Agreement in connection with such Clinical
Trials and the Initial Regulatory Filings, but excluding all of Amersham's [*]
costs and [*] costs, including without limitation [*], if any, attributable to
such Clinical Trial or the Initial Regulatory Filings.

        1.33 "INITIAL DEVELOPMENT PLAN" shall mean a full plan (rather than a
summary thereof) (a) that includes a detailed budget and specifies the means by
which (i) Corixa will seek to obtain Initial Approval for the Product in the
Territory, including a description of and estimated timeline for all regulatory
activities, and (ii) Amersham will establish the European Facility and (b) which
has been approved by the CSC in accordance with Section 4.2 or 4.3.

        1.34 "INITIAL REGULATORY FILINGS" shall have the meaning set forth in
Section 5.6.

        1.35 "INTELLECTUAL PROPERTY RIGHTS" shall mean all Patents, copyrights,
regulatory filings, Know-How, or any other intellectual property other than
trademarks, that are Controlled during the term of this Agreement by a Party or
jointly by the Parties and that relate to the development, manufacture,
importing, use, marketing and/or sale of the Product. The term "Intellectual
Property Rights" shall include any rights obtained by either Party from a Third
Party, including those obtained pursuant to Section 2.7, subject to the terms
and conditions of the agreements in which such rights were conferred. The term
"Intellectual Property Rights," however, shall not include Patents, copyrights,
regulatory filings, know-how and/or trade secrets, or any other intellectual
property of either Party for the [*], whether developed prior to or after the
Effective Date.

        1.36 "INVENTION" means any invention, development, result, Know-How or
other Information, and all intellectual property relating thereto, made,
discovered or developed (i) solely by a Party and its employees or agents
pursuant to work performed under the Agreement or (ii) jointly by the Parties
and their employees or agents pursuant to work performed under the Agreement.

        1.37 "IODINE I 131 TOSITUMOMAB" shall mean any therapeutic, prophylactic
or palliative product [*] or [*] the [*] conjugated with 131Iodine that was one
of the active agents tested in Corixa's clinical trial with Protocol No.
RIT-II-004 as referred to in that Protocol as [*] anti CD20 murine monoclonal
antibody.

        1.38 "JOINT COMMERCIALIZATION COMMITTEE" and "JCC" shall have the
meanings given such terms in Section 3.3(a).


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        1.39 "JOINT DEVELOPMENT COMMITTEE" and "JDC" shall have the meanings
given such terms in Section 3.2(a).

        1.40 "JOINT OTHER INVENTIONS" means any and all Other Inventions made
jointly by employees or agents of both Parties pursuant to work conducted under
the Agreement.

        1.41 "KNOW-HOW" shall mean any technical information that is secret and
identified.

        1.42 "MAA" shall mean a Marketing Authorization Application, the
regulatory application in the European Community that is the equivalent of a
BLA, for the Product.

        1.43 "MAJOR MARKET COUNTRIES" means UK, France, Germany, Spain and
Italy.

        1.44 "MARKETING PLAN" shall mean a full plan (rather than a summary
thereof) prepared by Amersham (as amended from time to time) that specifies the
means by which Amersham intends to commercialize the Product in the Territory,
including a description of and estimated timeline for all marketing and
promotional activities.

        1.45 "MICHIGAN AGREEMENT" shall mean the Commercialization Agreement
between Coulter Corporation and the Regents of the University of Michigan, dated
November 1, 1994, and the Amendment to Commercialization Agreement between
Coulter and the Regents of the University of Michigan, dated June 1, 1997.

        1.46 "NET SALES" shall mean gross amounts invoiced for sales of the
Product in the Territory by either Party, its Affiliates or sublicensees, as
appropriate, to Third Parties, less the following items: (i) trade, quantity and
cash discounts or rebates actually allowed and taken and any other adjustments,
including, without limitation, those granted on account of [*]; (ii) credits,
rebates, charge-back and prime vendor rebates, fees, reimbursements or similar
payments granted or given to [*] and other [*]; (iii) any tax, tariff, customs
duties, excise or other duties or other governmental charge (other than an
income tax) levied on the sale, transportation or delivery of a Product and
borne by the seller thereof; (iv) payments or rebates paid in connection with
sales of Products to any governmental or regulatory authority in respect of any
medical insurance funded by a state or federal government; and (v) any charge
for freight, insurance or other transportation costs charged to the customer.
For clarity, Net Sales shall not include: sales of the Product by and between a
Party and its Affiliates (except where such Affiliates are end users).

        1.47 "OTHER INVENTION" means any Invention that is not a Product
Invention.

        1.48 "PATENT" means (i) unexpired letters patent (including inventor's
certificates) that have not been held invalid or unenforceable by a court of
competent jurisdiction from which no appeal can be taken or has been taken
within the required time period, including without limitation any substitution,
extension, registration, confirmation, reissue, re-examination, renewal or any
like filing thereof and (ii) pending applications for letters patent, including
without limitation any continuation, division or continuation-in-part thereof
and any provisional applications.

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        1.49 "PRICING APPROVAL" shall mean any and all Regulatory Approvals with
respect to the price of the Product in a regulatory jurisdiction in the
Territory.

        1.50 "PRODUCT" shall mean (a) Iodine I 131 Tositumomab as defined in
Section 1.37 or (b) any therapeutic, prophylactic or palliative product
containing or comprising Tositumomab as defined in Section 1.65 for use in
connection with a Iodine I 131 Tositumomab, in any formulation or mode of
administration.

        1.51 "PRODUCT IMPROVEMENT" means any Invention that pertains to the [*]
of the Product but does not pertain to [*] of Tositumomab. For clarity, a
particular Product Improvement may be a Product Invention or an Other Invention.

        1.52 "PRODUCT INVENTION" means any Invention that pertains [*] to, or
the [*] use of which is [*] to, the Product or its development, manufacture or
use.

        1.53 "QA/QC COSTS" shall mean Corixa's internal and external costs of
quality assurance and quality control work performed by or on behalf of Corixa
related to Product [*] of Tositumomab and Corixa Iodine I 131 Tositumomab, but
only to the extent that such quality assurance and quality control work is [*]
or [*]. QA/QC Costs shall include a reasonable allocation of Corixa's [*], and
shall include any allocation of the costs of [*] or any costs of [*] related to
Tositumomab.

        1.54 "REGULATORY APPROVAL" means any and all approvals (including
supplements, amendments, pre- and post-approvals, pricing and reimbursement
approvals), licenses, registrations or authorizations of any national,
supra-national (e.g., the European Commission or the Council of the European
Union), regional, state or local regulatory agency, department, bureau,
commission, council or other governmental entity, that are necessary for the
manufacture, distribution, use or sale of a product in a regulatory
jurisdiction.

        1.55 "REGULATORY FILING" shall mean a regulatory filing for the Product
in the Territory.

        1.56 "SECOND INDICATION" shall mean label claim(s) that are approved in
a Regulatory Approval received for a Product in the Territory, wherein such
Regulatory Approval is subsequent to the Initial Approval and such label claims
are for a different indication than the indication approved in the Initial
Approval.

        1.57 "SOLE OTHER INVENTIONS" means any and all Other Inventions made,
discovered or developed solely by a Party and its employees or agents pursuant
to work performed under the Agreement.

        1.58 "SPECIFICATIONS" shall mean the requirements and standards
pertaining to Tositumomab or Iodine I 131 Tositumomab (depending upon context)
and consistent with filings made for Regulatory Approval and all relevant
written agreements between Corixa and a Third Party with respect to manufacture
or supply of Tositumomab, Iodine I 131 Tositumomab or Product, which
specifications are set forth in the BLA identified by Biologics License



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Application Submission Tracking Number 125011, provided that such specifications
may be modified in writing by the Parties from time to time as follows: any
modifications to the Specifications shall be reasonably acceptable to both
Parties or required for approval of the Product in the Territory and shall be
reasonably consistent with respect to [*]. The Specifications shall be release
or stability specifications, as applicable, and each reference to Specifications
shall mean the type of such Specifications appropriate to the context.

        1.59 "STOCK PURCHASE AGREEMENT" shall mean that certain Stock Purchase
Agreement entered into by Corixa Corporation and Nycomed, Inc. as of the Signing
Date.

        1.60 "SUBSEQUENT CLINICAL TRIAL" shall mean each Clinical Trial
conducted hereunder except for the Initial Approval Clinical Trials.

        1.61 "SUBSEQUENT DEVELOPMENT PLAN" shall mean a full plan (rather than a
summary thereof) that includes a detailed budget and specifies the means by
which Amersham will develop the Product other than in connection with the
Initial Approval, including the means by which Amersham will seek to obtain
Regulatory Approvals other than the Initial Approval for the Product in each
country in the Territory and including a description of and estimated timeline
for all regulatory activities, Subsequent Clinical Trials and any further
activities related to establishing the European Facility and which has been
approved by the CSC in accordance with Section 4.2 or 4.3.

        1.62 "SUBSEQUENT REGULATORY FILINGS" shall have the meaning set forth in
Section 5.8.

        1.63 "TERRITORY" shall mean the countries and territories of Europe set
forth on Exhibit B.

        1.64 "THIRD PARTY" means any entity other than (i) Corixa, (ii) Amersham
or (iii) an Affiliate of either of them.

        1.65 "TOSITUMOMAB" shall mean the [*] that (i) has not been conjugated
with 131 Iodine or any other [*] and (ii) was administered to patients in
Corixa's clinical trial with Protocol No. RIT-II-004 as referred to in that
Protocol as [*] anti CD20 murine monoclonal antibody. Except as otherwise
specified in this Agreement, Tositumomab shall mean both bulk and filled
material.

2.      LICENSES AND EXCLUSIVITY

        2.1 LICENSES TO AMERSHAM.

            (a) DEVELOPMENT AND COMMERCIALIZATION. Subject to Sections 5.2 and
5.3 and the other terms and conditions of this Agreement, Corixa hereby grants
Amersham an exclusive, royalty-bearing license under Corixa Intellectual
Property Rights, Product Inventions and Product Improvements Controlled by
Corixa, to develop, use, sell, offer for sale and import Product in the Field
and in the Territory. Notwithstanding the exclusivity of the foregoing


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                                       9.
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license, Corixa retains the right to continue and complete any and all Clinical
Trials in the Territory for which enrollment commenced prior to the Effective
Date and the right to carry out Initial Approval Clinical Trials and prepare and
file Initial Regulatory Filings as set forth herein. The license granted in this
Section 2.1(a) may be sublicensed by Amersham (i) in the Major Market Countries,
with the [*] of Corixa and (ii) in all other countries in the Territory, with
[*] to Corixa.

            (b) MANUFACTURING. Subject to the terms and conditions of this
Agreement, Corixa hereby grants Amersham a royalty-bearing license, under Corixa
Intellectual Property Rights, Product Inventions and Product Improvements
Controlled by Corixa, to make and have made, solely for the purpose of
satisfying Amersham's requirements for Product for use (as permitted in Section
2.1(a)) in the Field and in the Territory, (i) Iodine I 131 Tositumomab from
Tositumomab provided by Corixa, and (ii) Product from Tositumomab provided by
Corixa. The license granted in this Section 2.1(b) may be sublicensed by
Amersham, with the prior written consent of Corixa, to an Affiliate of Amersham
or to a Third Party with whom Amersham has entered into a written agreement for
the limited purpose of carrying out Amersham's manufacturing obligations under
this Agreement. During the period that Corixa is supplying Corixa Iodine I 131
Tositumomab to Amersham pursuant to the Supply Agreement, the license granted in
this Section 2.1(b) shall be co-exclusive among Amersham, Corixa and Corixa's
Third Party supplier(s) of Iodine I 131 Tositumomab. After the end of such
period, such license shall be exclusive to Amersham, subject to conversion of
such license to non-exclusive pursuant to Section 2.1(d). For clarity, the
foregoing license shall not be interpreted to prevent Corixa from making in the
Territory Tositumomab or Iodine I 131 Tositumomab for use outside the Territory.

            (c) SECOND SITE SUPPLY. If the events described in Section 3.1(e) of
the Supply Agreement occur, Corixa shall grant Amersham, subject to the terms
and conditions of this Agreement, a non-exclusive, royalty-bearing license under
Corixa Intellectual Property Rights, to make and have made, solely for the
purpose of satisfying Amersham's requirements for Product for use (as permitted
in Section 2.1(a)) in the Field and in the Territory, (i) Tositumomab, (ii)
Iodine I 131 Tositumomab manufactured from such Tositumomab, and (iii) Product
from such Tositumomab. The license granted in this Section 2.1(c) may be
sublicensed by Amersham, with the prior written consent of Corixa, which consent
shall not be unreasonably withheld, to an Affiliate of Amersham or to a Third
Party with whom Amersham has entered into a written agreement for the limited
purpose of carrying out Amersham's manufacturing obligations under this
Agreement.

            (d) CONVERSION TO NON-EXCLUSIVE LICENSES. The licenses set forth in
Sections 2.1(a) and (b) shall automatically convert to non-exclusive licenses on
the later of: (i) the expiration, cancellation or abandonment of the last
surviving issued patent or pending patent application in the Territory that
claims any Corixa Intellectual Property Right, Product Invention or Product
Improvement Controlled by Corixa and (ii) [*] years after the First Commercial
Sale of the Product in the Territory.

        2.2 NEGATIVE COVENANT. Amersham covenants that it shall not, nor shall
it cause any Affiliate or sublicensee to, knowingly use or practice directly or
indirectly, any Corixa Intellectual Property Rights, Product Inventions or
Product Improvements Controlled by Corixa for any purposes other than those
expressly permitted by this Agreement.

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        2.3 LICENSE TO CORIXA. Subject to the terms and conditions of this
Agreement, Amersham hereby grants Corixa a worldwide, non-exclusive,
royalty-free, perpetual license (with the right to sublicense only in
conjunction with a Corixa product or other intellectual property Controlled by
Corixa) to make and use, for any purpose, Product Improvements Controlled by
Amersham.

        2.4 NEGATIVE COVENANT. Corixa covenants that it shall not, nor shall it
cause any Affiliate or sublicensee to, knowingly use or practice directly or
indirectly any Product Improvements Controlled by Amersham for any other
purposes other than those expressly permitted by this Agreement.

        2.5 COVENANT NOT TO SUE. Amersham hereby agrees that it shall not assert
in any way any Patent or Know-How against Corixa or its Affiliates, or any of
their licensees, distributors, manufacturers or customers, direct or indirect,
in connection with the manufacture, use, import, offer for sale or sale of
Products manufactured in accordance the manufacturing procedures in use on the
Effective Date. If Amersham assigns or attempts to assign ownership of any of
its Patents to a Third Party not bound by this covenant not to sue (whether
directly or by operation of law), then effective upon such assignment or
attempted assignment, Corixa and its Affiliates and each of their licensees,
distributors and manufacturers, shall have and Amersham hereby grants Corixa in
the event of such circumstance, a worldwide, nonexclusive, nontransferable,
royalty-free license, without right of sublicense, under such assigned Patents
to make, use, import, offer for sale and sell Products manufactured in
accordance the manufacturing procedures in use on the Effective Date.

        2.6 EXISTING THIRD PARTY LICENSES. Amersham acknowledges and agrees to
be bound by all applicable provisions of the Dana Farber Agreements and Michigan
Agreement (including without limitation those provisions regarding royalty
payments, insurance and indemnification) as set forth in the letter between the
Parties of even date herewith, provided that such applicable provisions do not
violate any law or regulations in the Territory. Corixa and Amersham agree that
in the event any of the royalty obligations contained in the Third Party
licenses decrease or cease for whatever reason, Amersham shall also be entitled
to such a decrease or cessation of such royalty obligations.

        2.7 NEW THIRD PARTY LICENSES.

            (a) In the event Amersham believes that one or more licenses under
intellectual property held by a Third Party are necessary in order to assure [*]
activities under this Agreement involving the Product [*] do not infringe the
intellectual property rights of such Third Party, then the Parties will discuss
the situation in good faith and [*] shall make the determination as to whether
or not to license such intellectual property. Any license fees or royalties
payable to Third Parties pursuant to such a license agreement between Amersham
and a Third Party shall be borne by [*] and deducted from [*].

            (b) In the event Amersham believes that one or more licenses under
intellectual property held by a Third Party are desirable in order to assure
Amersham that its


-----------

* Confidential Treatment Requested.


                                      11.
<PAGE>

activities under this Agreement do not infringe the intellectual property rights
of such Third Party, then the Parties will discuss the situation in good faith
and Amersham shall make the determination as to whether or not to license such
intellectual property. Any license fees or royalties payable to Third Parties
pursuant to such a license agreement between Amersham and a Third Party shall be
borne by Amersham.

            (c) In the event Corixa believes that one or more licenses under
intellectual property held by a Third Party are necessary in order to assure
Corixa that its manufacture of Tositumomab or Iodine I 131 Tositumomab and other
activities under this Agreement for the Territory do not infringe the
intellectual property rights of such Third Party, then the Parties will discuss
the situation in good faith and [*] shall make the determination as to whether
or not to license such intellectual property. Any license fees or royalties
payable to Third Parties pursuant to such a license agreement between Corixa and
a Third Party shall be initially borne by [*] and, to the extent applicable to
the manufacture of Tositumomab or Corixa Iodine I 131 Tositumomab provided by
Corixa hereunder for the sale of Product in the Territory, shall be [*] as part
of the Fully Allocated Cost of such Tositumomab or Corixa Iodine I 131
Tositumomab and such [*] in Fully Allocated Cost shall be deducted from [*].

            (d) In the event Corixa believes that one or more licenses under
intellectual property held by a Third Party are desirable in order to assure
Corixa that its manufacture of Tositumomab or Iodine I 131 Tositumomab and other
activities under this Agreement for the Territory do not infringe the
intellectual property rights of such Third Party, then the Parties will discuss
the situation in good faith and [*] shall make the determination as to whether
or not to license such intellectual property. Any license fees or royalties
payable to Third Parties pursuant to such a license agreement between Corixa and
a Third Party shall be borne by [*] and [*] be passed on to [*] as part of the
Fully Allocated Cost of such Tositumomab or Corixa Iodine I 131 Tositumomab.

            (e) If the Parties disagree whether a particular Third Party
intellectual property is necessary or desirable to avoid infringing activities
by a Party pursuant to this Agreement, such disagreement shall be settled in
accordance with the dispute resolution procedures set forth in Section 14.1.

        2.8 EXCLUSIVITY. If Amersham or any Affiliate of Amersham files an MAA
or other application for Regulatory Approval in the Territory, to market an [*]
(other than [*] and whether [*] to any [*]) for [*] or for which [*], Amersham
shall immediately notify Corixa. Corixa may at any time thereafter, upon [*]
months prior written notice to Amersham, terminate the licenses contained in
Section 2.1 or convert such licenses to nonexclusive.

        2.9 U.N. CONVENTION NOT APPLICABLE. The Parties agree that the U.N.
Convention on Contracts for International Sales of Goods shall not apply to this
Agreement.


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* Confidential Treatment Requested.

                                      12.
<PAGE>

3.      GOVERNANCE STRUCTURES

        3.1 COLLABORATION STEERING COMMITTEE (CSC).

            (a) PURPOSE; FORMATION. Within thirty (30) days after the Effective
Date, the Parties will appoint their respective representatives to a
collaboration steering committee to oversee, coordinate and provide strategic
direction to the development, registration and commercialization of the Product
for and in the Territory and to approve the plans, budgets and resource
allocations for such activities (the "Collaboration Steering Committee" or
"CSC").

            (b) MEMBERSHIP. Each Party shall initially appoint two (2)
representatives to the CSC. The CSC may change its size from time to time by
mutual consent of its members; provided that the CSC shall at all times consist
of an equal number of representatives of each of Corixa and Amersham. Each Party
may replace its CSC representatives at any time upon written notice to the other
Party. At least one (1) of each Party's representatives on the CSC will have the
title of Vice-President (or a comparable position) or above for such Party. The
CSC may invite nonmembers to participate in the discussions and meetings of the
CSC, provided that such participants shall have no voting authority at the CSC.

            (c) CO-CHAIRPERSONS. Each Party will name, from among its two (2)
CSC representatives, a co-chairperson of the CSC. The co-chairpersons of the CSC
shall be responsible for the administering CSC meetings but shall have no
additional powers or rights beyond those held by the other CSC representatives.
The Parties' co-chairpersons will alternate responsibility for preparing minutes
of CSC meetings, which shall be circulated for review and approval by all
members within thirty (30) days after each meeting.

            (d) DECISION-MAKING. The CSC shall act by unanimous vote, with each
Party having one (1) vote. If the CSC becomes deadlocked on an issue that is not
a Corixa Matter or an Amersham Matter, then either Party may refer the matter
for dispute resolution pursuant to Section 14.1 by written notice to the other
Party. If the CSC becomes deadlocked on an issue that is a Corixa Matter, then
Corixa shall decide how such issue shall be handled. Such Corixa decision shall
be final and not subject to the dispute resolution procedures set forth in
Section 14.1. If the CSC becomes deadlocked on an issue that is an Amersham
Matter, then Amersham shall decide how such issue shall be handled. Such
Amersham decision shall be final and not subject to the dispute resolution
procedures set forth in Section 14.1.

            (e) MEETINGS. The CSC shall meet at least once per calendar quarter
after the Effective Date until Initial Approval, and at least two (2) times per
year thereafter during the term of this Agreement, unless the Parties mutually
agree in writing to a different frequency. Either co-chairperson may call a
special meeting of the CSC from time to time to address issues in connection
with which a decision or review is reasonably required prior to the next
regularly scheduled CSC meeting. The CSC will meet at locations alternately
selected by Corixa and by Amersham. The CSC may meet by video or audio
conference. Meetings of the CSC will be effective only if a representative of
each Party is present or participating. Each Party shall bear all expenses it
incurs in regard to participating in CSC meetings, including all travel and
living expenses.



                                      13.
<PAGE>

            (f) SPECIFIC RESPONSIBILITIES OF THE CSC. In addition to its general
responsibility to oversee, monitor, review, coordinate and provide strategic
direction to the development, registration and commercialization of the Product
for and in the Territory, the CSC shall in particular:

                  (i) Review, revise and approve each Development Plan
(including without limitation the Development Budget contained therein) as
provided in Sections 4.2, 4.3 and 4.4;

                  (ii) Resolve, in accordance with Section 3.1(d), issues
presented to it by, and disputes among the JDC and/or the JCC;

                  (iii) Review as it deems appropriate the decisions of each of
the JDC and the JCC;

                  (iv) Designate the Initial Approval Clinical Trials pursuant
to Section 4.5 or 5.4; and

                  (v) Perform any other functions set forth for the CSC in this
Agreement.

            (g) LIMITED AUTHORITY. The CSC shall have no authority to amend this
Agreement. The CSC shall have no authority to override any decision of Corixa
with respect to a Corixa Matter or any decision of Amersham with respect to an
Amersham Matter.

        3.2 JOINT DEVELOPMENT COMMITTEE (JDC).

            (a) PURPOSE; FORMATION. Within thirty (30) days after the Effective
Date the Parties will appoint their respective representatives to a joint
development committee to manage the development strategies, plans and budgets
for Regulatory Approval of the Product in the Territory (the "Joint Development
Committee" or "JDC"). The JDC shall dissolve upon mutual agreement of the
Parties, but in no event prior to two (2) years following Initial Approval.

            (b) MEMBERSHIP. Each Party shall initially appoint two (2)
representatives to the JDC. The JDC may change its size from time to time by
mutual consent of its members; provided that the JDC shall consist at all times
of an equal number of representatives of each Corixa and Amersham. Each Party
may replace its JDC representatives at any time upon written notice to the other
Party. At least one (1) of each Party's representatives will have the title of
Vice-President (or a comparable position) or above for such Party. The JDC may
invite nonmembers to participate in the discussions and meetings of the JDC,
provided that such participants shall have no voting authority at the JDC. A
member of the JDC may also be a member of the JCC.

            (c) CHAIRPERSON. Corixa shall name, from among its JDC
representatives, a chairperson of the JDC who shall act as chairperson until
Initial Approval. Following Initial Approval, Amersham shall name, from among
its JDC representatives, a chairperson of the JDC who shall act as chairperson
thereafter. The chairperson shall be responsible for administering JDC meetings
but shall have no additional powers or rights beyond those held by the other


                                      14.
<PAGE>

representatives on the JDC. The chairperson will be responsible for preparing
minutes of JDC meetings, which shall be circulated for review and approval by
all members within thirty (30) days after each meeting.

            (d) DECISION-MAKING. The JDC shall act by unanimous vote, with each
Party having one (1) vote. Should the JDC become deadlocked on any issue, then
it shall submit such issue to the CSC for resolution.

            (e) MEETINGS. The JDC shall meet at least once per calendar quarter
after the Effective Date until Initial Approval, and at least two (2) times per
year thereafter until completion of all activities to be performed pursuant to
the Subsequent Development Plan, unless the Parties mutually agree in writing to
a different frequency or to earlier disband the JDC. The chairperson may call a
special meeting of the JDC from time to time to address issues in connection
with which a decision or review is reasonably required prior to the next
regularly scheduled JDC meeting. The JDC will meet at locations alternately
selected by Corixa and by Amersham. The JDC may meet by video or audio
conference. Meetings of the JDC shall be effective only if a representative of
each Party is present or participating. Each Party shall report to the JDC on
all material issues relating to the development of Product for and in the
Territory promptly after such issues arise. Each Party shall bear all expenses
it incurs in regard to participating in meetings of the JDC.

            (f) SPECIFIC RESPONSIBILITIES OF THE JDC. In addition to its general
responsibility to manage, monitor, review and coordinate the development and
Regulatory Approval of the Product in the Territory according to the Development
Plans and to ensure a regular flow of development information among the Parties,
the JDC shall in particular:

                  (i) revise each draft Development Plan prepared by the Parties
and present the revised draft Development Plan to the CSC, all in accordance
with Sections 4.2 and 4.3;

                  (ii) review, coordinate and approve all plans for clinical,
manufacturing and radiolabeling activities with respect to the Product in or for
the Territory;

                  (iii) facilitate the flow of information between the Parties
with respect to all development of the Product for and in the Territory;

                  (iv) establish the levels of supply of Product needed for the
Initial Approval Clinical Trials as provided in Section 4.5 and for Subsequent
Clinical Trials; and

                  (v) perform any other responsibilities set forth for the JDC
in this Agreement.

           (g) LIMITED AUTHORITY. The JDC shall have only those powers expressly
assigned it in this Agreement. Without limiting the generality of the foregoing,
the JDC shall have no authority to amend the Development Plan or this Agreement.
The CSC may, at its discretion, review any decision of the JDC. The JDC shall
have no authority to override any decision of the CSC, any decision of Corixa
with respect to any Corixa Matter or any decision of Amersham with respect to
any Amersham Matter.



                                      15.
<PAGE>

        3.3 JOINT COMMERCIALIZATION COMMITTEE (JCC).

            (a) PURPOSE; FORMATION. Within ninety (90) days after the Effective
Date the Parties will appoint their respective representatives to a joint
commercialization committee to manage the strategies, plans and budgets for
commercialization of the Product in the Territory (the "Joint Commercialization
Committee" or "JCC").

            (b) MEMBERSHIP. Each Party shall initially appoint two (2)
representatives to the JCC. The JCC may change its size from time to time by
mutual consent of its members; provided that the JCC shall consist at all times
of an equal number of representatives of each Corixa and Amersham. Each Party
may replace its JCC representatives at any time upon written notice to the other
Party. At least one (1) of each Party's representatives will have the title of
Vice-President (or a comparable position) or above for such Party. The JCC may
invite nonmembers to participate in the discussions and meetings of the JCC,
provided that such participants shall have no voting authority at the JCC. A
member of the JCC may also be a member of the JDC.

            (c) CHAIRPERSON. Amersham shall name, from among its JCC
representatives, a chairperson of the JCC. The chairperson shall be responsible
for administering JCC meetings but shall have no additional powers or rights
beyond those held by the other representatives on the JCC. The chairperson will
be responsible for preparing minutes of JCC meetings, which shall be circulated
for review and approval by all members within thirty (30) days after each
meeting.

            (d) DECISION-MAKING. The JCC shall act by unanimous vote, with each
Party having one (1) vote. Should the JCC become deadlocked on any issue, then
it shall submit such issue to the CSC for resolution.

            (e) MEETINGS. The JCC shall meet at least two (2) times per year
after the Effective Date until submission of the MAA, and at least once per
calendar quarter thereafter until one (1) year following the First Commercial
Sale after which the JCC shall again meet at least two (2) times per year
throughout the term of this Agreement, unless the Parties mutually agree in
writing to a different frequency or to disband the JCC. The chairperson may call
a special meeting of the JCC from time to time to address issues in connection
with which a decision or review is reasonably required prior to the next
regularly scheduled JCC meeting. The JCC will meet at locations alternately
selected by Corixa and by Amersham. The JCC may meet by video or audio
conference. Meetings of the JCC shall be effective only if a representative of
each Party is present or participating. Each Party shall report to the JCC on
all material issues relating to the commercialization of Product for and in the
Territory promptly after such issues arise. Each Party shall bear all expenses
it incurs in regard to participating in meetings of the JCC.

            (f) SPECIFIC RESPONSIBILITIES OF THE JCC. In addition to its general
responsibility to manage, monitor, review and coordinate the commercialization
of the Product in the Territory according to the Marketing Plan and to ensure a
regular flow of development information among the Parties, the JCC shall in
particular:



                                      16.
<PAGE>

                  (i) Oversee the activities of Amersham in marketing, selling
and distributing Product in the Territory, including pre-launch and post-launch
activities;

                  (ii) Review and comment on the Marketing Plan and all updates
thereto, as provided in Section 7.1;

                  (iii) Monitor Amersham's compliance with the Marketing Plan;
and

                  (iv) Perform any other responsibilities set forth for the JDC
in this Agreement.

            (g) LIMITED AUTHORITY. The JCC shall have only those powers
expressly assigned it in this Agreement. Without limiting the generality of the
foregoing, the JCC shall have no authority to amend the Marketing Plan or this
Agreement. The CSC may, at its discretion, review any decision of the JCC. The
JCC shall have no authority to override any decision of the CSC, any decision of
Corixa with respect to any Corixa Matter or any decision of Amersham with
respect to any Amersham Matter.

4.      DEVELOPMENT; GOVERNANCE; DILIGENCE

        4.1 OVERVIEW. Corixa shall be responsible, under the direction of the
JDC and CSC, for carrying out all development activities for the Product in the
Territory in accordance with the Initial Development Plan, including without
limitation clinical development and regulatory filing for the Initial Approval
of the Product. Amersham shall, upon Corixa's request, mutual agreement of the
Parties and under Corixa's management, perform any of the foregoing development
activities. Corixa will be responsible for and bear all costs included in the
Development Budget to achieve Initial Approval of the Product throughout the
Territory as further specified in this Agreement, with the exception that
Amersham shall be responsible for and bear all costs of establishing a
radiolabeling facility in the Territory as further specified in this Agreement
and the Supply Agreement. The initial focus of the development efforts for the
Product in the Territory will be for the treatment of relapsed and/or refractory
low grade non-Hodgkin's lymphoma. Corixa shall be responsible for such
development as specified in Section 5.2(a)(iv). The development shall be
performed in accordance with the Development Plan and within the Development
Budget contained therein as amended from time to time. Corixa and Amersham shall
provide the JDC with regular reports detailing their respective development
activities and the results thereof, so that the JDC can monitor the Product's
development progress in the Territory.

        4.2 INITIAL DEVELOPMENT PLAN. An outline of the general areas to be
covered by the Initial Development Plan is attached hereto as Exhibit C. Within
60 days after Amersham's receipt of the data to be provided by Corixa pursuant
to Section 5.1(b), the Parties shall develop their appropriate portions (as
decided by the JDC) of a draft of the Initial Development Plan. When the JDC has
finished its review of, commentary upon and revision of such draft Initial
Development Plan, it shall present the revised draft Initial Development Plan to
the CSC for its approval, provided that such draft shall be presented to the CSC
not later than four (4) months following the Signing Date unless the Parties
agree otherwise. The CSC may approve such revised draft Initial Development
Plan, request that the JDC further revise such draft, or itself



                                      17.
<PAGE>

revise such draft. The Initial Development Plan and all updates thereto shall
become contractual obligations of the Parties once such Development Plan is
approved by the CSC.

        4.3 UPDATES TO DEVELOPMENT PLAN.

            (a) INITIAL DEVELOPMENT PLAN. On or before July 1st of each year
commencing in 2002 until Initial Approval, Corixa and Amersham shall develop
their appropriate portions and present to the JDC a draft updated Initial
Development Plan that reflects the goals and Development Budget for the Initial
Approval activities for the upcoming calendar year. The JDC shall review and, if
necessary, revise such draft updated Initial Development Plan. The JDC shall
present the resulting draft updated Initial Development Plan to the CSC for the
upcoming calendar year on or before September 1st of each year. The CSC may
approve, revise or request that the JDC revise the draft updated Initial
Development Plan. The CSC shall approve an updated Initial Development Plan for
the upcoming calendar year on or before October 1st of the preceding calendar
year.

            (b) SUBSEQUENT DEVELOPMENT PLAN. On or before July 1st of each year
commencing in the year that the MAA for Initial Approval is filed with the EMEA
or such earlier year as the Parties may agree, Amersham shall develop and
present to the JDC a draft Subsequent Development Plan that reflects the goals
and Development Budget for any activities proposed by Amersham to be carried out
to develop the Product in the Territory other than in connection with the
Initial Approval. The JDC shall review and, if necessary, revise such draft
updated Subsequent Development Plan. The JDC shall present the resulting draft
updated Subsequent Development Plan to the CSC for the upcoming calendar year on
or before September 1st of each year. The CSC may approve, revise or request
that the JDC revise the draft updated Subsequent Development Plan. The CSC shall
approve an updated Subsequent Development Plan for the upcoming calendar year on
or before October 1st of the preceding calendar year.

            (c) INTERMITTENT. Either Party may at any time propose updates and
changes to the then-current Development Plan to the JDC for its consideration.
If the JDC considers that such update of change is desirable, then it may revise
the Development Plan accordingly and submit such revised draft to the CSC for
its approval. Until and unless the CSC approves any proposed update or change to
the Development Plan, the Development Plan last approved by the CSC, and not the
draft revised Development Plan shall be effective.

        4.4 DEVELOPMENT BUDGET.

            (a) The Development Plan shall contain a separate Development Budget
for each Clinical Trial. The Development Plan shall also specify (i) those [*]
who shall be [*] and (ii) the amount to be paid by [*] for each such [*] as
determined in accordance with [*].

            (b) Corixa shall pay, in accordance with the mechanism set forth in
Section 8.7, all Initial Approval Trial Costs solely to the extent that such
Initial Approval Trial Costs are within the Development Budget for the Initial
Approval Clinical Trials. All costs


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* Confidential Treatment Requested.


                                      18.
<PAGE>

within the Development Budget that are not Initial Approval Trial Costs for the
Initial Approval Clinical Trials shall be the responsibility of Amersham.

        4.5 Responsibility, Approval and Designation of Clinical Trials.

            (a) INITIAL CLINICAL TRIAL. Corixa shall have the responsibility to
conduct all Clinical Trials required for Initial Approval in the Territory. If a
particular Clinical Trial included in the Development Plan is an Initial
Approval Clinical Trial, the JDC shall designate it as such.

            (b) SUBSEQUENT CLINICAL TRIALS. All Clinical Trials not needed for
Initial Approval shall be automatically designated as Subsequent Clinical Trials
and shall be the responsibility of Amersham. Corixa shall have the right to
reject any Subsequent Clinical Trial proposed by Amersham if Corixa reasonably
believes would negatively affect Regulatory Approval in the US of an expanded
label for the Product. Amersham shall have the right to have any such rejection
by Corixa discussed at the next-scheduled CSC meeting.

        4.6 FORECASTS OF SUPPLY FOR INITIAL APPROVAL CLINICAL TRIAL. The JDC
will agree upon the levels of supply of Product required for the Initial
Approval Clinical Trial, which amounts Amersham will include in the Amersham
Forecasts (and separately identify as Products for the Initial Approval Clinical
Trial) pursuant to the Supply Agreement. For the avoidance of doubt, such levels
shall be deemed to be a Corixa Matter, and if the JDC is unable to agree such
levels, Corixa shall make the final decision.

        4.7 DEVELOPMENT DILIGENCE.

            (a) GENERAL REQUIREMENT. Corixa shall use efforts of a sustained
manner consistent with the efforts Corixa devotes to other product development
of similar market potential, profit potential or strategic value resulting from
Corixa's own efforts, based on conditions then prevailing to obtain Initial
Approval of the Product and to carry out the tasks set forth in the Initial
Development Plan then in effect, as specified therein.

            (b) DILIGENCE BY CORIXA. Corixa shall initiate, perform and complete
the Initial Approval Clinical Trial in a timely manner and in accordance with
the approved Development Plan and shall file an MAA in a timely manner after
completion of the Initial Approval Clinical Trial and the availability of an
integrated full report (i.e., containing [*] and [*]) for the Initial Approval
Clinical Trial. Notwithstanding the foregoing, if Corixa's failure to perform an
action specified in this Section 4.7(b) within the timeframe specified in the
Initial Development Plan, or otherwise in a timely manner, is due, at least in
part, to a delay caused by Amersham, Corixa shall be entitled to an extension of
such timeframe equal to the amount of such Amersham delay.

            (c) DILIGENCE BY AMERSHAM. Amersham shall use Diligent Efforts to
carry out the tasks set forth in the (i) Initial Development Plan then in
effect, as specified therein as responsibilities of Amersham or as requested by
Corixa in accordance with Section 4.1; and (ii) Subsequent Development Plan then
in effect, as specified therein. Notwithstanding the foregoing, if Amersham's
failure to perform an action specified in this Section 4.7(c) within the
timeframe specified in the Initial Development Plan or the Subsequent
Development Plan, as



                                      19.

----------------
*Confidential Treatment Requested.
<PAGE>

applicable, or otherwise in a timely manner, is due, at least in part, to a
delay caused by Corixa, Amersham shall be entitled to an extension of such
timeframe equal to the amount of such Corixa delay.

5.      CLINICAL TRIALS AND REGULATORY ISSUES

        5.1 TRANSFER OF PRE-EXISTING FILES AND DATA.

            (a) FILES. Within thirty (30) days after the Effective Date, Corixa
shall transfer to Amersham copies of all relevant clinical files and regulatory
files for the Product in the Territory in Corixa's possession on the Effective
Date. Corixa shall retain ownership of such clinical and regulatory files and
may use such files for any purpose, including, but not limited to,
cross-referencing such files in clinical and regulatory filings in the Corixa
Territory.

            (b) DATA. Within thirty (30) days after the Effective Date, Corixa
shall provide Amersham with copies of all preclinical data relating to the
Product in Corixa's possession on the Effective Date and all data in Corixa's
possession at such time from Clinical Trials initiated prior to the Effective
Date. Corixa will provide Amersham all pertinent information that is owned by
Corixa and that is necessary to establish a radiolabeling facility and/or that
is related to the manufacture of Corixa Iodine I 131 Tositumomab or Amersham
Iodine 131 Tositumomab and is required to file for approval of the Product by
Regulatory Authorities in the Territory. The data described in this Section
5.1(b) above is the Confidential Information of Corixa, and Amersham may use
such data solely for the purpose of obtaining Regulatory Approval of or
marketing the Product in the Territory. Corixa shall also arrange for Amersham
to have a right of cross reference to all regulatory filings in the Corixa
Territory made by or on behalf of Corixa that include data from the Clinical
Trials that are identified as "Closed" on Exhibit D, as well as from Clinical
Trials CP-98-020 and CP-98-021. Amersham shall have the right to use, solely for
the purpose of obtaining Regulatory Approval of or marketing the Product in the
Territory, any data generated or created in relation to or as a result of such
regulatory filings.

        5.2 CLINICAL TRIALS SOLELY IN THE TERRITORY.

            (a) RESPONSIBILITIES.

                  (i) EXISTING. Corixa shall retain responsibility for and shall
solely bear the costs of all Clinical Trials in the Territory initiated (i.e.,
enrollment began for the trial as a whole) prior to the Effective Date, which
Clinical Trials are identified on Exhibit D hereto. Corixa shall promptly
provide Amersham with copies of, the data from such Clinical Trials that are
identified as "Closed" on Exhibit D, as well as from Clinical Trials CP-98-020
and CP-98-021.

                  (ii) ADDITIONAL. Responsibility for carrying out all Clinical
Trials that the Development Plan specifies shall be initiated after the
Effective Date and conducted solely in the Territory shall be in accordance with
Section 4.5.

                  (iii) COSTS OF TRIALS. Corixa will bear the Initial Approval
Trial Costs for the Initial Approval Clinical Trials, provided the Initial
Approval Clinical Trials are within



                                      20.
<PAGE>

the Development Budget for the Initial Approval Clinical Trials. In the event a
Party incurs costs (including its own internal costs) associated with the
Initial Approval Clinical Trials that are not within the Development Budget for
the Initial Approval Clinical Trials, the Party incurring such costs shall be
solely responsible therefore, provided that if Amersham incurs such costs at the
express direction of Corixa in accordance with Section 4.1, Corixa shall
reimburse Amersham therefor. Amersham will bear the Clinical Trial Costs of all
Subsequent Clinical Trials conducted solely in the Territory.

                  (iv) CORIXA ASSISTANCE. Amersham may seek Corixa's advice and
assistance regarding the conduct of Subsequent Clinical Trials solely in the
Territory. Corixa shall provide all such advice and assistance that is
reasonably requested by Amersham. Amersham shall reimburse Corixa for all
out-of-pocket and personnel expenses (at the FTE Rate) incurred in connection
with providing such advice and assistance with respect to any Subsequent
Clinical Trial.

           (b) ACCESS TO DATA.

                  (i) Corixa shall own and have the right to use (and sublicense
others to use) all data from the Initial Approval Clinical Trials for the
purpose of obtaining Regulatory Approval of or marketing the Product outside the
Territory. If Amersham becomes, pursuant to Section 5.7, the owner of any
Regulatory Filing containing data from the Initial Approval Clinical Trials,
Corixa shall continue to own such data and Amersham shall take all appropriate
measures to grant Corixa a right of reference to such Regulatory Filing for such
purpose.

                  (ii) If Corixa desires to use the data from any Subsequent
Clinical Trial conducted by Amersham solely in the Territory during the term of
the Agreement, for the purpose of Corixa or its corporate partner, Affiliate or
sublicensee obtaining Regulatory Approval of or marketing the Product in the
United States, Corixa shall provide written notice of such desire to Amersham
and Corixa shall bear [*] percent ([*]%) of Clinical Trial Costs associated with
such Clinical Trial and Amersham shall bear the remaining [*] percent ([*]%) of
such Clinical Trial Costs. If Corixa desires to use the data from any Subsequent
Clinical Trial conducted by Amersham solely in the Territory during the term of
the Agreement, for the purpose of Corixa or its corporate partner, Affiliate or
sublicensee obtaining Regulatory Approval of or marketing the Product in all
other countries of the Corixa Territory, Corixa shall provide written notice of
such desire to Amersham and Corixa shall bear [*] percent ([*]%) of Clinical
Trial Costs associated with such Clinical Trial and Amersham shall bear the
remaining [*] percent ([*]%) of such Clinical Trial Costs. Amersham shall
arrange for Corixa to have a right of cross reference to all Regulatory Filings
made by or on behalf of Amersham that include data from a Subsequent Clinical
Trial for which Corixa paid a percentage of the costs in accordance with this
Section 5.2(b)(ii). Corixa shall have the right to use, solely for the purpose
of obtaining Regulatory Approval of or marketing the Product in the Corixa
Territory, any data generated or created in relation to or as a result of any
such Regulatory Filing.

        5.3 CLINICAL TRIALS SOLELY IN THE CORIXA TERRITORY. In the event that
Amersham desires to use the data from any Clinical Trial conducted in the Corixa
Territory during the term


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                                      21.
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of the Agreement, including any data from any of the Clinical Trials identified
on Exhibit D other than those that are identified as "Closed" on Exhibit D or
Clinical Trial CP-98-020 and CP-98-021, for the purpose of obtaining Regulatory
Approval of or marketing the Product in the Territory, Amersham shall provide
written notice of such desire to Corixa and, Amersham shall bear [*] percent
([*]%) of Clinical Trial Costs associated with such Clinical Trial and Corixa
shall bear the remaining [*] percent ([*]%) of such Clinical Trial Costs. Corixa
shall arrange for Amersham to have a right of cross reference to all regulatory
filings in the Corixa Territory made by or on behalf of Corixa that include data
from a Clinical Trial for which Amersham paid a percentage of the costs in
accordance with this Section 5.3. Amersham shall have the right to use, solely
for the purpose of obtaining Regulatory Approval of or marketing the Product in
the Territory, any data generated or created in relation to or as a result of
such regulatory filing.

        5.4 CROSS-TERRITORY CLINICAL TRIALS.

            (a) INITIATION OF CROSS-TERRITORY CLINICAL TRIAL. If either Party
desires to conduct a new Cross-Territory Clinical Trial (which may be an
expansion of an existing Clinical Trial solely in the Territory or the Corixa
Territory), the JDC shall discuss such proposed Cross-Territory Clinical Trial.
If the JDC agrees upon a proposed protocol, budget and the allocation between
the Parties of the Clinical Trial Costs for such proposed Cross-Territory
Clinical Trial, then the JDC will present a proposal containing such information
to the CSC for approval. The CSC shall be entitled to approve, reject, revise or
request that the JDC revise and resubmit to the CSC such proposal. If the CSC
approves any such proposal, Amersham shall be responsible for the performance of
such Cross-Territory Clinical Trial in the Territory and Corixa (together with
Glaxo SmithKline in the United States) shall be responsible for the performance
of such Cross-Territory Clinical Trial in the Corixa Territory. In the event
that the Parties do not agree, neither Party shall have the right to conduct a
Clinical Trial in the other Party's Territory. In the event of a disagreement
between the Parties regarding the design or conduct of a Cross-Territory
Clinical Trial, either may opt out of the trial. If a Party does so opt out of a
Cross-Territory Clinical Trial, it shall have no further obligation to the other
Party to conduct such Cross-Territory Clinical Trial in its territory (the
Corixa Territory or the Territory, as the case may be). Notwithstanding anything
herein to the contrary, the Initial Approval Clinical Trial shall not be deemed
to be a Cross-Territory Trial even if it is conducted in both the Territory and
the Corixa Territory.

            (b) ACCESS TO DATA. The Parties shall have equal access to all data
generated in the course of a Cross-Territory Clinical Trial. Corixa shall own
all such data and such data shall be deemed to be Product Inventions. Amersham
shall be entitled to use such data in the Territory and Corixa shall be entitled
to use such data in the Corixa Territory. Each Party (the "Filing Party") shall
arrange for the other Party (the "Non-filing Party") to have a right of cross
reference to all regulatory filings in the Filing Party's territory made by or
on behalf of the Filing Party that include data from a Cross-Territory Clinical
Trial. The Non-filing Party shall have the right to use, solely for the purpose
of obtaining Regulatory Approval of or marketing the Product in the Non-filing
Party's territory, any data generated or created in relation to or as a result
of such regulatory filing.

        5.5 CLINICAL TRIAL COSTS AUDIT. Each Party (the "Auditing Party") shall
have the right, upon prior written notice to the other Party (the "Audited
Party") and at the Auditing



                                      22.

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<PAGE>

Party's cost, to have the certified public accountants of the Auditing Party's
choice, bound by confidentiality and reasonably acceptable to the Audited Party,
audit the Audited Party's books and records to verify the Audited Party's
calculations of any Clinical Trial Costs of which the Auditing Party is
obligated to pay a percentage. Each Party may exercise this right no more than
once per contract year.

        5.6 INITIAL REGULATORY FILINGS.

            (a) ACTIONS. Subject to Section 5.7, Corixa or its designee shall be
the owner of any and all MAAs for Initial Approval and all other applicable
Regulatory Filings for Initial Approval (collectively, "Initial Regulatory
Filings"). Corixa shall, in accordance with the then-current Development Plan
and the guidance of the JDC and CSC:

                  (i) prepare, file and prosecute in Corixa's name all Initial
Regulatory Filings;

                  (ii) be responsible for attending to all administrative
matters necessary to compile and submit the Initial Regulatory Filings; and

Amersham shall be responsible for maintaining the Initial Regulatory Filings
after the MAA has been transferred to Amersham pursuant to Section 5.7. The JDC
shall determine which Party shall be responsible for preparing the various
sections of the Initial Regulatory Filings and such responsibilities shall be
set forth in the Initial Development Plan. Corixa will keep Amersham informed of
its regulatory activities on an ongoing and timely basis at least as frequently
as the JDC is required to meet pursuant to Section 3.2. In addition, Corixa
shall provide Amersham with drafts of all Initial Regulatory Filings at least
thirty (30) days before they are filed and Amersham shall have the right to
comment thereon; provided that Corixa shall not be obligated to provide such
drafts nor shall Amersham have the right to comment thereon if the Parties have
agreed that Amersham shall not participate in the Initial Regulatory Filings.
Without limiting the foregoing, the responsible party, as determined by the JDC,
shall provide the other with each section of any draft MAA filing as it is
completed in order that the other may review and comment thereon.

            (b) COSTS. Subject to Section 5.9, Corixa will bear, as part of the
Initial Approval Trial Costs, all [*] costs and [*] costs incurred by Amersham
in the course of Amersham's preparation, filing, prosecution and maintenance of
the Initial Regulatory Filings, provided such costs are approved in advance as
part of a Development Budget, or otherwise approved in advance in writing by
Corixa.

        5.7 TRANSFER OF INITIAL REGULATORY FILINGS. Unless the Parties agree
otherwise, reasonably promptly after Amersham makes the milestone payment set
forth in Section 8.2(a), Corixa shall transfer and assign to Amersham all
Initial Regulatory Filings.

        5.8 SUBSEQUENT REGULATORY FILINGS. Amersham shall at its own expense:


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            (a) prepare, file and prosecute in its name all Regulatory Filings
for purposes other than Initial Approval ("Subsequent Regulatory Filings"),
including without limitation all Regulatory Filings to enable the lawful sale of
the Product to treat any Second Indication;

            (b) be responsible for all administrative matters necessary to
compile and submit Subsequent Regulatory Filings;

            (c) be responsible for maintaining the Subsequent Regulatory
Filings; and

            (d) bear the registration renewal fees for the Subsequent Regulatory
Filings.

Amersham will keep Corixa informed of its regulatory activities pursuant to this
Section 5.8 on an ongoing and timely basis at least as frequently as the JDC is
required to meet at such time pursuant to Section 3.2. In addition, Amersham
shall provide Corixa with drafts of all Subsequent Regulatory Filings at least
thirty (30) days before they are filed and the JDC shall have the right to
comment thereon. Without limiting the foregoing, Amersham shall provide Corixa
with each section of any draft "subsequent" MAA filing as it is completed in
order that Corixa may review and comment thereon.

        5.9 PRICING APPROVALS AND PRICING. Amersham shall be responsible, at its
own expense, for seeking Pricing Approval for the Product in the Territory.
Amersham shall keep Corixa informed on an ongoing basis of Amersham's strategy
for seeking and results it obtains in seeking Pricing Approval for the Product
in each such country of the Territory, including without limitation the results
of any discussion or other communication with relevant governmental authorities
regarding Pricing Approval, via regular reports to the JDC no less frequently
than such committee is required to meet pursuant to Section 3.2. Amersham shall
also inform Corixa regarding its general pricing plans (that do not require
Pricing Approval) for the Product in the Territory.

        5.10 UPDATES. Amersham shall prepare and provide to the JDC in advance
of each JDC meeting a written report summarizing the work done by Amersham
pursuant to this Agreement, including without limitation under the Development
Plan. Between such reports, Amersham shall keep Corixa via its JDC members
reasonably informed of material developments relating to the activities
performed by Amersham hereunder, especially as to the manufacture of Amersham
Iodine I 131 Tositumomab and Initial Approval of the Product in the Territory.

        5.11 RECORDS. Amersham shall maintain complete and accurate records of
all work conducted under this Agreement and all results, data and developments
made pursuant to its efforts under this Agreement. Such records shall fully and
properly reflect all work done and results achieved in the performance of this
Agreement in sufficient detail and in good scientific manner appropriate for
patent and regulatory purposes. Corixa shall have the right to review such
records at reasonable times to the extent necessary for Corixa to monitor
Amersham's performance of its obligations under this Agreement.



                                      24.
<PAGE>

6.      REGULATORY COMPLIANCE

        6.1 ADVERSE EVENT REPORTING. Each Party shall advise the other Party of
any adverse reaction to the use of the Product or any increase in the severity
or frequency of such an adverse reaction, by telephone or facsimile as soon as
possible and within such time as is required by the FDA or the equivalent
agencies in the Territory after the Party becomes aware of such adverse
reaction. Such advising Party shall provide the other Party with a written
report delivered by confirmed facsimile of any reported adverse reaction,
stating the full facts known to it, including but not limited to an identifiable
patient (identified by a unique identifier that does not reveal the identity of
the patient, whenever possible); a suspect medicinal product (including batch,
lot, or serial number, as appropriate); an identifiable reporting source
(including name, address, and telephone numbers); and an identifiable outcome or
event. Amersham shall report all adverse reactions occurring in the Territory to
the relevant authorities in accordance with applicable law. Promptly after the
Effective Date, the JDC shall begin to develop written adverse event reporting
procedures including but not limited to provision of Periodic Safety Update
Reports and other safety reports required by regulatory authorities, and shall
submit a set of such procedures to the CSC for approval as promptly as is
reasonably practicable. Within six (6) months after the Effective Date, the
Parties shall agree in writing, upon adverse event reporting procedures that are
consistent with and effectuate the goals of this Section 6.1.

        6.2 COMPLIANCE.

            (a) Amersham shall comply with all applicable laws, statutes,
regulations, orders and health registration laws of any government entity in the
Territory and with all other governmental requirements relating to the
development, regulatory registration, manufacturing and supply, and marketing of
the Product in the Territory.

            (b) Corixa shall use [*] efforts to cause its Third Party suppliers
engaged in the manufacture of the Product to comply with all of such Third
Party's obligations to Corixa related to compliance with applicable laws,
statutes, regulations, orders and health registration laws of any government
entity in the Territory and with all other governmental requirements relating to
the development, regulatory registration, manufacturing and supply, and
marketing of the Product in the Territory.

        6.3 PRODUCT COMPLAINTS. Each Party shall maintain a record of all
complaints it receives with respect to the Product (each, a "Product
Complaint"). For purposes of this Section 6.3, a "Product Complaint" is a report
of an actual or potential failure of the Product to meet the standards set forth
in regulatory filings or in agreements among the Parties. The responsibilities
of the Parties with respect to (a) notification of the Product Complaint from
the receiving Party to the other Party and (b) the handling of Product
Complaints shall all be performed in accordance with a procedure to be mutually
agreed by the Parties after the Effective Date.

        6.4 PRODUCT RECALL. The Parties shall immediately inform each other in
writing of all information related to (a) any incident relating to a Product
and/or any lot of a Product that is the subject of recall, market withdrawal or
correction, or (b) any Product that may require, whether


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                                      25.
<PAGE>

based on manufacturing defect, tampering, or otherwise, a recall, field alert,
product withdrawal or field correction arising from any defect in any such
Product. If either Party believes that a recall of Tositumomab and/or Iodine I
131 Tositumomab is desirable or required by law, it will promptly notify the
other Party. The Parties will then discuss reasonably and in good faith whether
such recall is appropriate or required and the manner in which any recall shall
be handled; provided, however, in the event either Party determines that a
recall is necessary, such recall shall be implemented. Amersham shall be solely
responsible for the handling and disposition of such recalls of Product in the
Territory, and Amersham shall be responsible for all costs related to any such
recall. Corixa shall cooperate with Amersham in allowing such recall in the
Territory to occur. Within six (6) months after the Effective Date, the Parties
shall agree in writing, upon product recall procedures that are consistent with
and effectuate the goals of this Section 6.4.

7.      MARKETING

        7.1 MARKETING PLAN. Amersham shall submit a proposed initial Marketing
Plan to the JCC within thirty (30) days after filing the MAA in the Territory.
The JCC may suggest revisions to the Marketing Plan or any updated Marketing
Plan and Amersham shall consider in good faith the JCC's proposed revisions to
such Marketing Plan and incorporate those that are commercially reasonable.
Amersham shall update the Marketing Plan each time a new Regulatory Approval is
obtained for the Product in the Territory and no less often than once a year.

        7.2 DILIGENCE.

            (a) Amersham shall use its best efforts to promote, market and sell
the Product in each country and territory in the Territory in which Regulatory
Approval has been received and to carry out the tasks set forth in the Marketing
Plan at the times specified therein.

            (b) In addition to the obligations set forth in Section 7.2(a),
Amersham shall make the First Commercial Sale of each Product in each country
within three (3) months after receiving Regulatory Approval of the Product in
such country.

        7.3 REPORTING. Amersham will keep the JDC informed of its marketing
activities on an ongoing and timely basis. In addition, upon request by Corixa,
Amersham shall inform Corixa in writing and in advance of implementation, of any
decisions that may significantly impact any part of the Corixa Territory for
Product.

8.      ECONOMICS

        8.1 EQUITY INVESTMENT. Amersham shall make an equity investment in
Corixa equal to a total of fifteen million dollars ($15,000,000) in accordance
with the terms set forth in the Stock Purchase Agreement.

        8.2 MILESTONES. Amersham shall pay Corixa the following non-refundable,
non-creditable amounts within five (5) business days after occurrence of each of
the events specified below:



                                      26.
<PAGE>

            (a) $[*] million upon [*].

            (b) $[*] million upon the first time that Annual Net Sales exceed
$[*].

            (c) $[*] million upon the first time that Annual Net Sales exceed
$[*].

            (d) $[*] million upon the first time that Annual Net Sales exceed
$[*].

            (e) $[*] million upon the first time that Annual Net Sales exceed
$[*].

            (f) $[*] million upon first [*].

        For the avoidance of doubt, in the event that Annual Net Sales in a
particular year exceed more than one amount that gives rise to a milestone
payment under this Section 8.2, then Amersham shall make all applicable
milestone payments. For example, if Annual Net Sales in a particular year are
$[*] and previous Annual Net Sales were less than $[*], Amersham shall make the
milestone payments set forth in Sections 8.2(b), (c) and (d) (for a total of
$[*]) with respect to such year.

        The events described in subsections (b) through (e) above shall be
deemed to have occurred on the earlier of (i) the date upon which Amersham's
accounting system determines that such Annual Net Sales have been achieved and
(ii) the end of the calendar quarter in which the final sale that causes such
achievement is made.

        8.3 ROYALTIES.

            (a) Subject to Section 8.3(b), in respect of the licenses granted in
Sections 2.1(a) and (b), Amersham shall pay Corixa a running royalty of [*]
percent ([*]%) of Net Sales.

            (b) The running royalty owed by Amersham pursuant to Section 8.3(a)
shall be reduced to the applicable percentage of Net Sales shown below in a
particular country of the Territory during such time as one of the following
circumstances is then in effect in such country:


<TABLE>
<CAPTION>
CIRCUMSTANCE                                             RUNNING ROYALTY
------------                                             ---------------
<S>                                                    <C>
(i)     there is [*]                                    [*]% of Net Sales

(ii)    there is [*]                                    [*]% of Net Sales

(iii)   there is [*]                                    [*]% of Net Sales

(iv)    there is [*]                                    [*]% of Net Sales
</TABLE>

            (c) In the event that more than one circumstance set forth in
Section 8.3(b) occurs simultaneously in a particular country, Amersham's running
royalty rate shall be



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                                      27.
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the lowest running royalty applicable to any of the circumstances. Multiple such
simultaneous circumstances shall not have an additive effect on running royalty
rates.

            (d) On a country-by-country basis, Amersham shall pay the royalties
set forth in this Section 8.3 until the later of: (i) the expiration,
cancellation or abandonment of the last surviving issued patent or pending
patent application in the Territory that claims any Corixa Intellectual Property
Right, Product Invention or Product Improvement Controlled by Corixa, or (ii)
such time as all Know-How in the Corixa Intellectual Property Rights, Product
Inventions or Product Improvements Controlled by Corixa ceases to be secret on
account of Corixa's actions.

            (e) The royalties set forth in this Section 8.3 do not include
royalties that Amersham is obligated to pay to Third Parties, including Dana
Farber and the University of Michigan.

        8.4 INDEPENDENT MANUFACTURE ROYALTIES. In the event that the license set
forth in Section 2.1(c) is granted, Amersham shall pay Corixa a running royalty
of [*] percent ([*]%) of Net Sales (excluding Net Sales of Product supplied by
Corixa under the Supply Agreement). The percentage rate of such running royalty
shall be subject to reduction, if applicable, in accordance with the rates and
conditions set forth in Section 4.1(b) of the Supply Agreement.

        8.5 QUARTERLY PAYMENTS AND PAYMENT REPORTS. All payments due under
Sections 8.3 and 8.4 shall be made to Corixa or its designee quarterly within 30
days following the end of each calendar quarter for which payments are due. Each
such payment shall be accompanied by a statement stating the number,
description, and aggregate Net Sales, by country, of each Product sold during
the relevant calendar quarter.

        8.6 PAYMENT METHOD. All payments due under this Agreement to Corixa
shall be made by bank wire transfer in immediately available funds to an account
designated by Corixa. All payments hereunder shall be made in U.S. dollars and
shall be noncreditable and nonrefundable.

        8.7 INVOICING OF INITIAL APPROVAL TRIAL COSTS. Amersham shall invoice
Corixa quarterly for Initial Approval Trial Costs that Amersham bears pursuant
to Sections 4.4, 5.2 and 5.6. Corixa shall pay the undisputed amount of each
such invoice within thirty (30) days after its receipt of such invoice. Corixa
shall be entitled to require Amersham to substantiate each invoice, and to audit
Amersham's records relating to the costs invoiced on the same basis as provided
for in Section 8.13, and late payments (on undisputed amounts) shall bear
interest, pursuant to Section 8.14.

        8.8 TAXES. Corixa shall pay any and all taxes levied on account of all
payments it receives under this Agreement. If laws or regulations require that
taxes be withheld, Amersham will (i) deduct those taxes from the remittable
payment, (ii) pay the taxes to the proper taxing authority, and (iii) send
evidence of the obligation together with proof of tax payment to Corixa within
60 days following that tax payment.


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                                      28.
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        8.9 CURRENCY OF PAYMENT. All dollar amounts contained in this Agreement
are in United States Dollars (US$).

        8.10 BLOCKED CURRENCY. In each country in the Territory where the local
currency is blocked and cannot be removed from the country, royalties accrued in
that country shall be paid to Corixa in the country in local currency by deposit
in a local bank designated by Corixa, unless the Parties otherwise agree.

        8.11 SUBLICENSES. In the event Amersham grants licenses or sublicenses
to others to sell Products which are subject to payments under Sections
8.2(b)-(e), 8.3 or 8.4, such licenses or sublicenses shall include an obligation
for the licensee or sublicensee to account for and report its sales of Products
on the same basis as if such sales were Net Sales by Amersham, and Amersham
shall pay to Corixa, with respect to such sales, royalties as if such sales of
the licensee or sublicensee were Net Sales of Amersham.

        8.12 FOREIGN EXCHANGE. Payments due on sales of the Product shall be
calculated and paid by Amersham in United States Dollars. Sales will be
converted into U.S. Dollars from locally billed currency on a monthly basis
using the exchange rates for the last trading day of the month as published by
Reuters. Royalties will be calculated on a quarterly calendar basis and payments
shall be due thirty (30) days after the completion of the quarter.

        8.13 RECORDS; INSPECTION. Amersham shall keep complete, true and
accurate books of account and records for the purpose of determining the
payments to be made under this Agreement. Such books and records shall be kept
for at least [*] years following the end of the calendar quarter to which they
pertain. Such records will open for inspection during such [*] year period by
independent accountants, solely for the purpose of verifying payment statements
hereunder. Such inspections shall be made no more than once each calendar year,
at reasonable time and on reasonable notice. Inspections conducted under this
Section 8.13 shall be at the expense of Corixa, unless a variation or error
producing an increase exceeding [*]% of the royalty amount stated for any period
covered by the inspection is established in the course of such inspection,
whereupon all costs relating to the inspection for such period and any unpaid
amounts (plus interest) that are discovered will be paid promptly by Amersham.

        8.14 LATE PAYMENT PENALTY. Any payment due under this Article 5 that is
not paid by [*] days after the payment's due date shall accrue interest, which
must be paid by the Party with the payment obligation to the recipient Party, on
a daily basis at a rate equal to [*] percent above the then-applicable reference
rate of CitiBank, N.A. San Francisco, California (or the maximum amount
permitted by law, if less), from the date first owed until paid.

9.      INTELLECTUAL PROPERTY

        9.1 OWNERSHIP. Corixa shall own the entire right, title and interest in
and to any and all Product Inventions, and Patents covering such Product
Inventions. Each Party shall own the entire right, title and interest in and to
any and all of its Sole Other Inventions, and Patents covering such Sole Other
Inventions. Amersham and Corixa shall each own an undivided one-half interest in
and to any and all Joint Other Inventions and Patents and other intellectual



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                                      29.
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property rights claiming or covering or arising from such Joint Other Inventions
(the "Joint Other Patents"), with inventorship to be determined under the patent
laws of the United States. Amersham and Corixa, as joint owners, shall each have
the right to practice and to grant licenses under such Joint Other Patents
without a duty of accounting, except as otherwise provided in this Agreement.
Amersham hereby covenants that it will not license any Joint Other Patents it
Controls for use in conjunction with [*].

        9.2 DISCLOSURE. Amersham shall submit a written report to Corixa within
[*] days of the end of each June and December during the term of this Agreement
describing any Product Invention arising during the prior half-year. The Parties
shall mutually decide whether to file a patent application for a Joint Other
Invention, as discussed in Section 9.3.

        9.3 PATENT PROSECUTION AND MAINTENANCE; ABANDONMENT.

            (a) Each Party shall retain control over and bear all expenses
associated with the filing, prosecution and maintenance of all Patents claiming
its Sole Other Inventions.

            (b) Corixa shall retain control over and bear all expenses
associated with the filing, prosecution and maintenance of all Patents claiming
Product Inventions.

            (c) The Parties' rights and obligations with respect to the filing,
prosecution and maintenance of Joint Other Patents shall be decided on a
case-by-case basis.

        9.4 ENFORCEMENT OF PATENT RIGHTS.

            (a) If either Party becomes aware of any Third Party activity in the
Territory that infringes an issued Patent in the Corixa Intellectual Property
Rights or an issued Patent claiming a Product Invention, then that Party shall
give prompt written notice to the other Party within [*] days after having
knowledge of such infringement. Corixa shall have the primary right, but not the
obligation, to institute, prosecute or control any action or proceeding with
respect to such infringement by counsel of its own choice.

            (b) If Corixa enforces a Patent that is part of the Corixa
Intellectual Property Rights or covers a Product Invention made by Amersham,
then (i) Amersham shall have the right (at its own expense) to participate in
such action and to be represented by counsel of its own choice, and (ii)
Amersham shall, at the request and expense of Corixa, be joined as a party to
the suit. Any damages or monetary award recovered shall be applied to reimburse
the reasonable costs and expenses of the Parties in connection with such
litigation and the balance shall be divided between Corixa and Amersham in
accordance with the percentage to which each such entity funded the suit.

            (c) If Corixa fails to bring an action or proceeding to enforce a
Patent that is part of the Corixa Intellectual Property Rights or covers a
Product Invention made by Amersham within a period of [*] days after such
notice, then Amersham shall have the right, but not the obligation, to bring and
control any such action by counsel of its own choice, and Corixa shall have the
right to participate in such action and to be represented, at its own expense,
by counsel



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                                      30.
<PAGE>

of its own choice. Any damages or monetary award recovered shall be applied to
reimburse the reasonable costs and expenses of the Parties in connection with
such litigation and the balance shall be divided between Corixa and Amersham in
accordance with the percentage to which each such entity funded the suit.

        9.5 DEFENSE OF THIRD PARTY CLAIMS.

            (a) If a claim is brought by a Third Party that any activity related
to the Agreement or a Product infringes the intellectual property rights of such
Third Party, each Party will give prompt written notice to the other Party of
such claim. If the Third Party claim arises from Corixa's activities under the
Agreement, Corixa shall control and bear the expense of its own defense and,
except as set forth in Section 9.5(b), Corixa shall defend, indemnify and hold
harmless Amersham, which shall include costs or judgments whether for money or
equitable relief, and reasonable legal expenses and reasonable attorney's fees.
Corixa shall not enter into a settlement agreement with such Third Party without
the written consent of Amersham, which shall not be unreasonably withheld. If
the Third Party claim arises from Amersham's activities under the Agreement or
from a Product, Amersham shall control and bear the expense of its own defense
and Amersham shall defend, indemnify and hold harmless Corixa, which shall
include costs or judgments whether for money or equitable relief, and reasonable
legal expenses and reasonable attorney's fees. Amersham shall not enter into a
settlement agreement with such Third Party without the written consent of
Corixa, which shall not be unreasonably withheld.

            (b) Except as set forth in Section 9.5(a), each Party shall be
responsible for its own defense of such Third Party claims, at its own expense
and without indemnification by the other Party. In any event, neither Party
shall be required to conduct any work under this Agreement which it believes may
infringe Third Party rights. In the event the Third Party claim arises from the
manufacture, sale or use of a Product by Amersham or its licensee, the indemnity
obligations of Amersham under Section 9.5(a) shall apply, and Corixa shall not
have any indemnity obligation to Amersham in respect of such claims.

        9.6 TRADEMARKS. Amersham shall be responsible for the acquisition and
maintenance of trademarks for the Product in the Territory. Amersham is not
licensed to use any trademark Controlled by Corixa.

10.     CONFIDENTIALITY

        10.1 NONDISCLOSURE OF CONFIDENTIAL INFORMATION. All Information
disclosed by one Party to the other Party pursuant to this Agreement shall be
"Confidential Information." The Parties agree that during the term of this
Agreement, and for a period of five years after this Agreement expires or
terminates, a Party receiving Confidential Information of the other Party will
(i) maintain in confidence such Confidential Information to the same extent such
Party maintains its own proprietary industrial information of similar kind and
value (but at a minimum each Party shall use commercially reasonable efforts),
(ii) not disclose such Confidential Information to any Third Party without prior
written consent of the other Party, except for disclosures made in confidence to
any Third Party manufacturer of Tositumomab or Iodine I 131 Tositumomab, and
(iii) not use such Confidential Information for any purpose except those
permitted by this Agreement.



                                      31.
<PAGE>

        10.2 EXCEPTIONS. The obligations in Section 10.1 shall not apply with
respect to any portion of the Confidential Information that the receiving Party
can show by competent written proof:

            (a) Is publicly disclosed by the disclosing Party, either before or
after it is disclosed to the receiving Party hereunder; or

            (b) Was known to the receiving Party, without obligation to keep it
confidential, prior to disclosure by the disclosing Party; or

            (c) Is subsequently disclosed to the receiving Party by a Third
Party lawfully in possession thereof and without obligation to keep it
confidential; or

            (d) Has been published by a Third Party; or

            (e) Has been independently developed by the receiving Party without
the aid, application or use of Confidential Information.

            10.3 AUTHORIZED DISCLOSURE. A Party may disclose the Confidential
Information belonging to the other Party to the extent such disclosure is
reasonably necessary in the following instances:

            (a) Filing or prosecuting Patents relating to Sole Inventions, Joint
Inventions or Products;

            (b) Regulatory filings;

            (c) Prosecuting or defending litigation;

            (d) Complying with applicable governmental regulations; and

            (e) Disclosure, in connection with the performance of this
Agreement, to Affiliates, sublicensees, research collaborators, employees,
consultants, or agents, each of whom prior to disclosure must be bound by
similar obligations of confidentiality and non-use at least equivalent in scope
to those set forth in this Article 10.

        In addition, Corixa shall have the right to disclose Confidential
Information under in connection with discussing potential business transactions
involving the Product outside of the Territory provided that Corixa and the
party to which Corixa is disclosing the Confidential Information are parties to
a written confidentiality agreement.

        The Parties acknowledge that the terms of this Agreement shall be
treated as Confidential Information of both Parties. Such terms may be disclosed
by a Party to investment bankers, investors, and potential investors, each of
whom prior to disclosure must be bound by similar obligations of confidentiality
and non-use at least equivalent in scope to those set forth in this Article 10.
In addition, a copy of this Agreement may be filed by Corixa with the Securities
and Exchange Commission. In connection with any such filing, Corixa shall
endeavor to obtain confidential treatment of economic and trade secret
information.



                                      32.
<PAGE>

        In any event, the Parties agree to take all reasonable action to avoid
disclosure of Confidential Information except as permitted hereunder.

        10.4 TERMINATION OF PRIOR AGREEMENTS. This Agreement supersedes all
mutual non-disclosure agreements entered into by the Parties prior to the
Effective Date. All Information exchanged between the Parties under those
earlier agreements shall be deemed Confidential Information and shall be subject
to the terms of this Article 10.

        10.5 PUBLICITY. The Parties shall agree on the language of the public
announcement of the execution of this Agreement prior to the release thereof.
Any other publication, news release or other public announcement relating to
this Agreement or to the performance hereunder, shall first be reviewed and
approved by both Parties; provided, however, that any disclosure which is
required by law as advised by the disclosing Party's counsel may be made without
the prior consent of the other Party, although the other Party shall be given
prompt notice of any such legally required disclosure and to the extent
practicable shall provide the other Party an opportunity to comment on the
proposed disclosure. The Parties shall agree on language relating to this
Agreement which either Party may use without the repeated approval of the other
Party.

        10.6 PUBLICATIONS. Amersham shall not publish or present the results of
Clinical Trials carried out in the Territory under this Agreement without the
opportunity for prior review by Corixa. Subject to Section 10.3, Amersham agrees
to provide Corixa the opportunity to review any proposed abstracts, manuscripts
or presentations (including verbal presentations) which relate to any Product at
least 30 days prior to its intended submission for publication and agrees, upon
request, not to submit any such abstract or manuscript for publication until
Corixa is given a reasonable period of time to secure patent protection for any
material in such publication which it believes to be patentable. Both Parties
understand that a reasonable commercial strategy may require delay of
publication of information or filing of patent applications. The Parties agree
to review and consider delay of publication and filing of patent applications
under certain circumstances. Neither Party shall have the right to publish or
present Confidential Information of the other Party which is subject to Section
10.1. Nothing contained in this Section 10.6 shall prohibit the inclusion of
information necessary for a patent application, except for Confidential
Information of the nonfiling Party, provided the nonfiling Party is given a
reasonable opportunity to review the information to be included prior to
submission of such patent application.

11.     TERM AND TERMINATION

        11.1 TERM. This Agreement shall become effective on the Effective Date
and shall remain in effect until the expiration of the last payment obligation
pursuant to Article 8 with respect to any Product.

        11.2 AMENDMENT OF TERRITORY. At any time during the term of this
Agreement that is after the third (3rd) anniversary of the Effective Date,
Amersham may provide written notice identifying one or more countries in the
Territory (but not all countries in the Territory) for which it no longer wishes
to have rights and obligations under this Agreement. The Parties will
subsequently amend the Territory definition to delete such countries. The
effective date for such



                                      33.
<PAGE>

amendment will be [*] months after the date of such notice and this Agreement
shall terminate solely with respect to such country(ies) upon such effective
date.

        11.3 TERMINATION FOR MATERIAL BREACH.

             (a) If either Party believes that the other is in material breach
of this Agreement (including without limitation any material breach of a
representation or warranty made in this Agreement), then the non-breaching Party
may deliver notice of such breach to the other Party. In such notice the
non-breaching Party shall identify the actions or conduct that such Party would
consider to be an acceptable cure of such breach. The allegedly breaching Party
shall have [*] days to either cure such breach or, if cure cannot be reasonably
effected within such [*] day period, to deliver to the other Party a plan for
curing such breach which is reasonably sufficient to effect a cure. Such a plan
shall set forth a program for achieving cure as rapidly as practicable.
Following delivery of such plan, the breaching Party shall use Diligent Efforts
to carry out the plan and cure the breach. In the event of breach for failure to
meet any payment obligations under this Agreement, the breaching Party shall
have [*] days to cure such breach for nonpayment. For the avoidance of any
doubt, any failure on the part of Nycomed, Inc. to fulfill its obligations set
forth in the Stock Purchase Agreement shall be a material breach of this
Agreement.

             (b) If the Party receiving notice of breach fails to cure such
breach within the [*] period, or the Party providing the notice reasonably
determines that the proposed corrective plan or the actions being taken to carry
it out is not commercially practicable, the Party originally delivering the
notice may terminate this Agreement upon [*] days advance written notice. If
Corixa is the breaching Party, Amersham may elect to not terminate this
Agreement as provided herein but instead retain its licenses granted under
Section 2.1 subject to payment of fees and milestones under Article 8 and other
obligations under this Agreement. If the non-breaching Party elects not to
terminate this Agreement under circumstances in which such non-breaching Party
believes it is entitled to a temporary restraining order against the breaching
Party, it may seek such a temporary restraining order. After the issuance of any
temporary restraining order granted hereunder, any disputes concerning the
appropriateness of such temporary restraining order shall be resolved in
accordance with Section 14.1 and, if arbitration results, the arbitrator shall
have the right to grant the Party subject to such temporary restraining order
any redress that might have been available to such Party if the matter had
remained under the jurisdiction of the courts.

             (c) If a Party gives notice of termination under this Section 11.3
and the other Party disputes whether such notice was proper, then the issue of
whether this Agreement has been terminated shall be resolved in accordance with
Section 14.1. If as a result of such dispute resolution process it is determined
that the notice of termination was proper, then such termination shall be deemed
to have been effective [*] days following the date of the notice of termination.
If as a result of such dispute resolution process it is determined that the
notice of termination was improper, then no termination shall have occurred and
this Agreement shall have remained in effect.


----------
* Confidential Treatment Requested.


                                      34.
<PAGE>

        11.4 TERMINATION BY AMERSHAM.

             (a) Amersham shall have the right to terminate this Agreement upon
[*] days written notice to Corixa if the Product is legally blocked from being
marketed in the European Union for the indication for which the Parties were
attempting to obtain Initial Approval, as a result of the designation of a
competing product for such indication as an "orphan medicinal product" pursuant
to the applicable European Commission regulations.

             (b) Amersham shall have the right to terminate this Agreement with
respect to all countries of the Territory upon [*] months written notice to
Corixa at any time after the third (3rd) anniversary of the Effective Date.

             (c) Amersham shall have the right to terminate this Agreement upon
[*] days' written notice in the event that the EMEA fails to validate the MAA
filing because the MAA was deemed by the EMEA to be insufficient.

        11.5 TERMINATION BY CORIXA.

             (a) Corixa shall have the right to terminate this Agreement upon
[*] days written notice to Amersham in the event that Corixa terminates the
Supply Agreement pursuant to (i) Section 7.2 of the Supply Agreement on account
of Amersham's material breach of the Supply Agreement or (ii) Section 3.3(d) of
the Supply Agreement.

             (b) Corixa shall have the right to terminate this Agreement upon
[*] days written notice to Amersham in the event that an MAA containing data
from the first initiated Initial Approval Clinical Trial is not approved.

        11.6 TERMINATION BY MUTUAL AGREEMENT. The Parties may terminate this
Agreement at any time by mutual written agreement.

        11.7 EFFECT OF TERMINATION; SURVIVAL.

             (a) In the event of termination of this Agreement for any reason,
the following provisions of this Agreement shall survive: Sections 2.3, 2.5,
5.5, 8.13, 8.14, 9.1, 9.2, 9.3 and 11.7, and Articles 1, 10, 13 and 14.

             (b) If termination of this Agreement was not due to Corixa's
material breach pursuant to Section 11.3, then

                  (i) Amersham shall, within [*] days of such termination,
transfer all clinical data, manufacturing data, regulatory filings, and other
documents owned by Amersham to Corixa at no cost to Corixa; and

                  (ii) if Amersham commenced manufacture of Amersham Iodine I
131 Tositumomab prior to such termination, then


----------
* Confidential Treatment Requested.

                                      35.
<PAGE>

                      (1) Amersham shall also supply, for [*] months after such
termination, Amersham Iodine I 131 Tositumomab to Corixa at [*] cost determined
in accordance with the terms of the Supply Agreement;

                      (2) At its sole discretion, Corixa may extend, by [*]
months, the period in which Amersham is obligated to supply Amersham Iodine I
131 Tositumomab to Corixa. For all Amersham Iodine I 131 Tositumomab delivered
to Corixa during such [*]-month extension (if any), Corixa shall pay Amersham a
supply price not to exceed [*](1) that are directly attributable to the
conversion of [*] to [*] plus [*] of such costs; and

                      (3) At the request of Corixa, the Parties shall negotiate
in good faith towards an agreement whereby Amersham will supply Amersham Iodine
I 131 Tositumomab to Corixa for a period of time to be negotiated on
commercially reasonable terms, and shall include a supply price that will not
exceed [*] that are directly attributable to the conversion of [*] to [*] plus
[*] of such costs.

In the event of termination with respect to a particular country or particular
countries pursuant to Section 11.2, Amersham shall only be obligated to supply
to Corixa pursuant to this Section 11.7(b)(ii) in the country or countries for
which Amersham has terminated its rights and obligations hereunder.

            (c) In any event, termination of this Agreement shall not relieve
the Parties of any liability which accrued hereunder prior to the effective date
of such termination nor preclude either Party from pursuing all rights and
remedies it may have hereunder or at law or in equity with respect to any breach
of this Agreement nor prejudice either Party's right to obtain performance of
any obligation.

            (d) In the event that this Agreement is terminated (except for
termination pursuant to Section 11.3 (due solely to Corixa's material breach),
11.4(a), 11.5(b) or 11.6) and either

                  (i) Amersham does not commence manufacture of Amersham Iodine
I 131 Tositumomab by December 31, [*] or the date (if any) agreed in writing
pursuant to Section 3.3(a) of the Supply Agreement, or

                  (ii) Amersham fails for a period of more than [*] days, for
reasons other than [*] to supply Amersham Iodine I 131 Tositumomab to Corixa
during the [*]-month period set forth in Section 11.7(b)(ii)(1), then Corixa
shall have the right solely during the [*] months commencing (i) in the case of
subsection 11.7(b)(i), on December 31, [*] or the date (if any) agreed in
writing pursuant to Section 3.3(a) of the Supply Agreement or (ii) in the case
of subsection 11.7(b)(ii), at the end of the [*] day period described in
subsection 11.7(b)(ii), as applicable, to require Amersham to pay Corixa a
termination fee of [*] dollars ($[*]), which fee shall be payable by Amersham
within [*] days of Amersham's receipt of a letter from Corixa stating with
supporting documentation that the conditions set forth in this Section 11.7(d)
have occurred and requesting payment of such fee. In the event Corixa elects
payment of such


----------
(1) Such cost shall be determined in accordance with the terms of the Supply
Agreement.
* Confidential Treatment Requested.




                                      36.
<PAGE>

termination fee, then such fee shall be Corixa's sole remedy at law or in equity
for Amersham's failure to commence manufacture as set forth in subsection
11.7(d)(i) or failure to supply as set forth in subsection 11.7(d)(ii), as
applicable. In addition, in the event during the [*] month period described
above Corixa sues Amersham for material breach based on Amersham's failure to
commence manufacture as set forth in subsection 11.7(d)(i) or failure to supply
as set forth in subsection 11.7(d)(ii), Corixa's right to require Amersham to
pay such termination fee shall immediately terminate with no further action
required by either Party.

12.     REPRESENTATIONS AND COVENANTS

        12.1 MUTUAL AUTHORITY. Corixa and Amersham each represents and warrants
to the other that (i) it has the authority and right to enter into and perform
this Agreement and (ii) its execution, delivery and performance of this
Agreement will not conflict in any material fashion with the terms of any other
agreement to which it is or becomes a party or by which it is or becomes bound.

        12.2 PERFORMANCE BY AFFILIATES. The Parties recognize that each may
perform some or all of its obligations under this Agreement through Affiliates,
provided, however, that each Party shall remain responsible and be guarantor of
the performance by its Affiliates and shall cause its Affiliates to comply with
the provisions of this Agreement in connection with such performance. The
aforesaid liquidated damages of $[*] shall be Corixa's sole remedy at law or
equity for Amersham's failure to supply as set forth in 11.7(d)ii above.

13.     INDEMNIFICATION AND LIMITATION OF LIABILITY

        13.1 INDEMNIFICATION.

             (a) Amersham hereby agrees to defend and hold harmless Corixa and
its agents and employees from and against any and all suits, claims, actions,
demands, liabilities, expenses and/or loss, including reasonable legal expenses
and reasonable attorneys' fees ("Losses") resulting directly or indirectly from
(i) manufacture, use or storage by Amersham or its sublicensee or agent of
Tositumomab, Iodine I 131 Tositumomab or Product, (ii) sale of Product in the
Territory, or (iii) Amersham's breach of a material obligation under this
Agreement, except to the extent such Losses result from an activity as to which
Corixa is obliged to indemnify Amersham pursuant to Section 13.1(b).

             (b) Corixa hereby agrees to defend and hold harmless Amersham and
its agents and employees from and against any and all suits, claims, actions,
demands, liabilities, expenses and/or loss, including reasonable legal expenses
and reasonable attorneys' fees ("Losses") resulting directly or indirectly from
(i) the failure of Tositumomab provided to Amersham by Corixa or Corixa Iodine I
131 Tositumomab to comply with the relevant Specifications, (ii) the failure of
Corixa to comply with GMP during its manufacture of Tositumomab or Corixa Iodine
I 131 Tositumomab, or (iii) Corixa's breach of a material obligation under this
Agreement, except to the extent such Losses result from an activity as to which
Amersham is obliged to indemnify Corixa pursuant to Section 13.1(a).



----------
* Confidential Treatment Requested.

                                      37.
<PAGE>

             (c) In the event that a Party (the "Indemnified Party") is seeking
indemnification under Section 13.1(a) or (b), the Indemnified Party shall inform
the other Party (the "Indemnifying Party") of a claim as soon as reasonably
practicable after the Indemnified Party receives notice of the claim, shall
permit the Indemnifying Party to assume direction and control of the defense of
the claim (including the right to settle the claim solely for monetary
consideration), and shall cooperate as requested by the Indemnifying Party (at
the expense of the Indemnifying Party) in the defense of the claim.

        13.2 LIMITATION OF LIABILITY. EXCEPT AS SPECIFICALLY PROVIDED IN
SECTIONS 11.7(d) AND 13.1, IN NO EVENT SHALL EITHER PARTY, ITS DIRECTORS,
OFFICERS, EMPLOYEES, AGENTS OR AFFILIATES BE LIABLE TO THE OTHER PARTY FOR ANY
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES, WHETHER BASED
UPON A CLAIM OR ACTION OF CONTRACT, WARRANTY, NEGLIGENCE, STRICT LIABILITY OR
OTHER TORT, OR OTHERWISE, ARISING OUT OF THIS AGREEMENT. For clarification, the
foregoing sentence shall not be interpreted to limit or to expand the express
rights specifically granted in the sections of this Agreement.

        13.3 INSURANCE.

             (a) During the term of this Agreement and for a period of five
years after the expiration or termination of this Agreement, Amersham shall
maintain product liability insurance or indemnity policies with an insurer
reasonably satisfactory to Corixa, with a minimum amount not less than [*] U.S.
[*] Dollars (U.S. $[*]) per occurrence (or claim) and [*] U.S. [*] Dollars (U.S.
$[*]) annual aggregate limit of liability, and after the First Commercial Sale
in the Territory shall always maintain product liability insurance with a
minimum of [*] U.S Dollars (U.S. $[*]) per occurrence (or claim) and [*] U.S.
[*] Dollars (U.S. $[*]) annual aggregate limit of liability. Such policies shall
insure against liability on the part of Corixa and any of its Affiliates, as
their interests may appear, due to injury, disability or death of any person or
persons, or injury to property arising from any action or omission for which
Amersham has an indemnification obligation pursuant to Section 13.1(a).

             (b) During the term of this Agreement and for a period of five
years after the expiration or termination of this Agreement, Corixa shall
maintain product liability insurance or indemnity policies with an insurer
reasonably satisfactory to Amersham, with a minimum amount not less than [*]
U.S. [*] Dollars (U.S. $[*]) per occurrence (or claim) and [*] U.S. [*] Dollars
(U.S. $[*]) annual aggregate limit of liability. Such policies shall insure
against liability on the part of Amersham and any of its Affiliates, as their
interests may appear, due to injury, disability or death of any person or
persons, or injury to property arising from any action or omission for which
Corixa has an indemnification obligation pursuant to Section 13.1(b).

             (c) Each Party shall promptly notify the other Party of any
material alterations to the terms of such policies or in the amounts for which
insurance is provided.


----------
* Confidential Treatment Requested.

                                      38.
<PAGE>

14.     MISCELLANEOUS

        14.1 DISPUTE RESOLUTION. In the event of any controversy or claim
arising out of, relating to or in connection with any provision of this
Agreement other than a Corixa Matter or a Amersham Matter, the Parties shall try
to settle their differences amicably between themselves first, by referring the
disputed matter to the respective heads of Research and Development of each
Party and, if not resolved by the Research and Development heads, by referring
the disputed matter to the respective Chief Executive Officers of each Party.
Either Party may initiate such informal dispute resolution by sending written
notice of the dispute to the other Party, and, within 20 days after such notice,
such representatives of the Parties shall meet for attempted resolution by good
faith negotiations. If such personnel are unable to resolve a dispute within 30
days of their first meeting of such negotiations, except as provided in Section
14.3, either Party may seek to have such dispute resolved by binding arbitration
with a single arbitrator under the commercial rules of the American Arbitration
Association. The Parties hereby consent to conduct such binding arbitration
procedures in English in the city of New York, New York.

        14.2 GOVERNING LAW. Resolution of all disputes arising out of or related
to this Agreement or the performance, enforcement, breach or termination of this
Agreement and any remedies relating thereto, shall be governed by and construed
under the substantive laws of the State of Delaware, as applied to agreements
executed and performed entirely in the State of Delaware by residents of the
State of Delaware, without regard to conflicts of law rules.

        14.3 PATENTS AND TRADEMARKS. Any dispute, controversy or claim relating
to the scope, validity, enforceability or infringement of any Patent rights
covering the manufacture, use or sale of any Product or of any trademark rights
related to any Product shall be submitted to a court of competent jurisdiction
in the territory in which such Patent or trademark rights were granted or arose.

        14.4 ENTIRE AGREEMENT; AMENDMENT. This Agreement sets forth the
complete, final and exclusive agreement and all the covenants, promises,
agreements, warranties, representations, conditions and understandings between
the Parties hereto and supersedes and terminates all prior agreements and
understandings between the Parties. There are no covenants, promises,
agreements, warranties, representations, conditions or understandings, either
oral or written, between the Parties other than as are set forth herein and
therein. No subsequent alteration, amendment, change or addition to this
Agreement shall be binding upon the Parties unless reduced to writing and signed
by an authorized officer of each Party.

        14.5 EXPORT CONTROL. This Agreement is made subject to any restrictions
concerning the export of products or technical information from the United
States of America or other countries which may be imposed upon or related to
Corixa or Amersham from time to time. Each Party agrees that it will not export,
directly or indirectly, any technical information acquired from the other Party
under this Agreement or any products using such technical information to a
location or in a manner that at the time of export requires an export license or
other governmental approval, without first obtaining the written consent to do
so from the appropriate agency or other governmental entity.



                                      39.
<PAGE>

        14.6 BANKRUPTCY.

             (a) All rights and licenses granted under or pursuant to this
Agreement, including amendments hereto, by each Party to the other Party are,
for all purposes of Section 365(n) of Title 11 of the U.S. Code ("Title 11"),
licenses of rights to intellectual property as defined in Title 11. Each Party
agrees during the term of this Agreement to create and maintain current copies
or, if not amenable to copying, detailed descriptions or other appropriate
embodiments, to the extent feasible, of all such intellectual property. If a
case is commenced by or against either Party (the "Bankrupt Party") under Title
11, then, unless and until this Agreement is rejected as provided in Title 11,
the Bankrupt Party (in any capacity, including debtor-in-possession) and its
successors and assigns (including, without limitation, a Title 11 Trustee)
shall, at the election of the Bankrupt Party made within 60 days after the
commencement of the case (or, if no such election is made, immediately upon the
request of the non-Bankrupt Party) either (i) perform all of the obligations
provided in this Agreement to be performed by the Bankrupt Party including,
where applicable and without limitation, providing to the non-Bankrupt Party
portions of such intellectual property (including embodiments thereof) held by
the Bankrupt Party and such successors and assigns or otherwise available to
them or (ii) provide to the non-Bankrupt Party all such intellectual property
(including all embodiments thereof) held by the Bankrupt Party and such
successors and assigns or otherwise available to them.

             (b) If a Title 11 case is commenced by or against the Bankrupt
Party and this Agreement is rejected as provided in Title 11 and the
non-Bankrupt Party elects to retain its rights hereunder as provided in Title
11, then the Bankrupt Party (in any capacity, including debtor-in-possession)
and its successors and assigns (including, without limitations, a Title 11
Trustee) shall provide to the non-Bankrupt Party all such intellectual property
(including all embodiments thereof) held by the Bankrupt Party and such
successors and assigns or otherwise available to them immediately upon the
non-Bankrupt Party's written request therefor. Whenever the Bankrupt Party or
any of its successors or assigns provides to the non-Bankrupt Party any of the
intellectual property licensed hereunder (or any embodiment thereof) pursuant to
this Section 14.6, the non-Bankrupt Party shall have the right to perform the
obligations of the Bankrupt Party hereunder with respect to such intellectual
property, but neither such provision nor such performance by the non-Bankrupt
Party shall release the Bankrupt Party from any such obligation or liability for
failing to perform it.

             (c) All rights, powers and remedies of the non-Bankrupt Party
provided herein are in addition to and not in substitution for any and all other
rights, powers and remedies now or hereafter existing at law or in equity
(including, without limitation, Title 11) in the event of the commencement of a
Title 11 case by or against the Bankrupt Party. The non-Bankrupt Party, in
addition to the rights, power and remedies expressly provided herein, shall be
entitled to exercise all other such rights and powers and resort to all other
such remedies as may now or hereafter exist at law or in equity (including,
without limitation, under Title 11) in such event. The Parties agree that they
intend the foregoing non-Bankrupt Party rights to extend to the maximum extent
permitted by law and any provisions of applicable contracts with Third Parties,
including without limitation for purposes of Title 11, (i) the right of access
to any intellectual property (including all embodiments thereof) of the Bankrupt
Party or any Third Party with whom the Bankrupt Party contracts to perform an
obligation of the Bankrupt Party under this



                                      40.
<PAGE>

Agreement, and, in the case of the Third Party, which is necessary for the
development, registration and manufacture of licensed products and (ii) the
right to contract directly with any Third Party described in (i) in this
sentence to complete the contracted work. Any intellectual property provided
pursuant to the provisions of this Section 14.6 shall be subject to the licenses
set forth elsewhere in this Agreement and the payment obligations of this
Agreement, which shall be deemed to be royalties for purposes of Title 11.

        14.7 FORCE MAJEURE. Both Parties shall be excused from the performance
of their obligations under this Agreement to the extent that such performance is
prevented by force majeure and the nonperforming Party promptly provides notice
of the prevention to the other Party. Such excuse shall be continued so long as
the condition constituting force majeure continues and the nonperforming Party
takes reasonable efforts to remove the condition. For purposes of this
Agreement, force majeure shall include conditions beyond the control of the
Parties, including without limitation, an act of God, voluntary or involuntary
compliance with any regulation, law or order of any government, war, civil
commotion, labor strike or lock-out, epidemic, failure or default of public
utilities or common carriers, destruction of production facilities or materials
by fire, earthquake, storm or like catastrophe; provided, however, the payment
of invoices due and owing hereunder shall not be delayed by the payer because of
a force majeure affecting the payer.

        14.8 NOTICES. Any notice required or permitted to be given under this
Agreement shall be in writing, shall specifically refer to this Agreement and
shall be deemed to have been sufficiently given for all purposes if mailed by
first class certified or registered mail, postage prepaid, express delivery
service or personally delivered. Unless otherwise specified in writing, the
mailing addresses of the Parties shall be as described below.

                   For Corixa:         Senior VP, Chief Operating Officer
                                       Corixa Corporation
                                       1124 Columbia Street, Suite 200
                                       Seattle, WA 98104

                   With a copy to:     General Counsel
                                       Corixa Corporation
                                       1124 Columbia Street, Suite 200
                                       Seattle, WA 98104

                   With a copy to:     Cooley Godward LLP
                                       Five Palo Alto Square
                                       3000 El Camino Real
                                       Palo Alto, CA  94306
                                       Attention:  Robert L. Jones, Esq.

                   For Amersham:       Group Secretary
                                       Amersham PLC
                                       Amersham Place
                                       Little Chalfont
                                       Buckinghamshire
                                       ENGLAND HP7 9NA



                                      41.
<PAGE>

                   With a copy to:     General Counsel
                                       Nycomed Amersham
                                       101 Carnegie Center
                                       Princeton, NJ 08540

        14.9 CONSENTS NOT UNREASONABLY WITHHELD OR DELAYED. Whenever provision
is made in this Agreement for either Party to secure the consent or approval of
the other, that consent or approval shall not unreasonably be withheld or
delayed, and whenever in this Agreement provisions are made for one Party to
object to or disapprove a matter, such objection or disapproval shall not
unreasonably be exercised.

        14.10 MAINTENANCE OF RECORDS. Each Party shall keep and maintain all
records required by law or regulation with respect to Products and shall make
copies of such records available to the other Party upon request.

        14.11 UNITED STATES DOLLARS. References in this Agreement to "Dollars"
or "$" shall mean the legal tender of the United States of America.

        14.12 NO STRICT CONSTRUCTION. This Agreement has been prepared jointly
and shall not be strictly construed against either Party.

        14.13 ENGLISH. This Agreement has been prepared in English and shall be
interpreted solely in English.

        14.14 ASSIGNMENT. Neither Party may assign or transfer this Agreement or
any rights or obligations hereunder without the prior written consent of the
other, except a Party may make such an assignment without the other Party's
consent to an Affiliate or to a successor to substantially all of the business
of such Party, whether in a merger, sale of stock, sale of assets or other
transaction. Any permitted successor or assignee of rights and/or obligations
hereunder shall, in writing to the other Party, expressly assume performance of
such rights and/or obligations. Any permitted assignment shall be binding on the
successors of the assigning Party. Any assignment or attempted assignment by
either Party in violation of the terms of this Section 14.14 shall be null and
void and of no legal effect.

        14.15 HARDSHIP. If, during the term of the Agreement, performance of the
Agreement should lead to unreasonable hardship for one or other Party taking the
interests of both Parties into account both Parties shall endeavor to agree in
good faith to amend the Agreement in the light of the change in circumstances.

        14.16 ELECTRONIC DATA INTERCHANGE. If both Parties elect to facilitate
business activities hereunder by electronically sending and receiving data in
agreed formats (also referred to as Electronic Data Interchange or "EDI") in
substitution for conventional paper-based documents, the terms and conditions of
this Agreement shall apply to such EDI activities.



                                      42.
<PAGE>

        14.17 COUNTERPARTS. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

        14.18 FURTHER ACTIONS. Each Party agrees to execute, acknowledge and
deliver such further instruments, and to do all such other acts, as may be
necessary or appropriate in order to carry out the purposes and intent of this
Agreement.

        14.19 SEVERABILITY. If any one or more of the provisions of this
Agreement is held to be invalid or unenforceable by any court of competent
jurisdiction from which no appeal can be or is taken, the provision shall be
considered severed from this Agreement and shall not serve to invalidate any
remaining provisions hereof. The Parties shall make a good faith effort to
replace any invalid or unenforceable provision with a valid and enforceable one
such that the objectives contemplated by the Parties when entering this
Agreement may be realized. If the Parties, after making good faith effort, are
unable to effectively replace an invalid or unenforceable provision pursuant to
this Section 14.19, and a Party is suffering or reasonably expects to suffer
significant economic harm as a result of the invalidity or unenforceability of
an original provision of this Agreement, such Party shall have the right to
terminate this Agreement upon six (6) months prior written notice to the other
Party. Such termination shall be in accordance with the provisions of Section
11.3(b) of this Agreement.

        14.20 AMBIGUITIES. Ambiguities, if any, in this Agreement shall not be
construed against any Party, irrespective of which Party may be deemed to have
authored the ambiguous provision.

        14.21 HEADINGS. The headings for each article and section in this
Agreement have been inserted for convenience of reference only and are not
intended to limit or expand on the meaning of the language contained in the
particular article or section.

        14.22 NO WAIVER. Any delay in enforcing a Party's rights under this
Agreement or any waiver as to a particular default or other matter shall not
constitute a waiver of such Party's rights to the future enforcement of its
rights under this Agreement, excepting only as to an express written and signed
waiver as to a particular matter for a particular period of time.

        IN WITNESS WHEREOF, the Parties have executed this Agreement in
duplicate originals by their proper officers as of the date and year first above
written.

AMERSHAM PLC                                CORIXA CORPORATION

By: /s/ R. E. B. Allnult                    By: /s/ Steven Gillis
   ----------------------------                ------------------------------

Name: R. E. B. Allnult                      Name:  Steven Gillis
     --------------------------                    --------------------------

Title: Company Secretary                    Title: Chairman and Chief
     --------------------------                    --------------------------
                                                   Executive Officer
                                                   --------------------------

Date:  11/05/01                             Date:   10/31/01
     --------------------------                    --------------------------




                                      43.
<PAGE>

                                    EXHIBIT A

                                 CORIXA PATENTS


<TABLE>
<CAPTION>
ATTORNEY            SERIAL NO. /      FILED/
DOCKET NO.          PATENT NO.        ISSUED            COUNTRIES DESIGNATED                     TITLE
----------          ----------        ------            --------------------                     -----
<S>                <C>               <C>              <C>                                  <C>
COUL-               98928875.8        6/3/98           Austria, Belgium, Cyprus,           Radioprotectant for
003/01EP            Publication       Pub.             Switzerland & Liechtenstein,        Peptides Labeled
(Corixa owns)       No: EP 1 003      Date             Germany, Denmark, Spain,            with Radioisotope
                    560               5/31/00          Finland, France, United
                                                       Kingdom, Greece, Ireland,
                                                       Italy, Luxembourg, Monaco,
                                                       Netherlands, Portugal,
                                                       Sweden

COUL-               1999 5906         6/3/98           Norway                              Radioprotectant for
003/01NO                                                                                   Peptides Labeled
(Corixa owns)                                                                              with Radioisotope

COUL-               96916440.9        5/3/96           Austria, Belgium,                   Method of
005/02EP (UM        WO 96/34632       Pub.             Switzerland & Liechtenstein,        Establishing the
owns--Corixa is                        date            Germany, Denmark, Spain,            Optimal Radiation
exclusive                             11/7/96          Finland, France, United             Dose for
licensee)                                              Kingdom, Greece, Ireland,           Radiopharmaceutical
                                                       Italy, Luxembourg, Monaco,          Treatment of
                                                       Netherlands, Portugal,              Disease
                                                       Sweden

COUL-               99955224.3        6/4/99           Austria, Belgium, Cyprus,           Patient-Specific
005/04EP            WO 99/62565       Pub.             Switzerland & Liechtenstein,        Dosimetry
(Corixa/UM co-                        Date             Germany, Denmark, Spain,
owners--license                        12/9/99         Finland, France, United
to Corixa)                                             Kingdom, Greece, Ireland,
                                                       Italy, Luxembourg, Monaco,
                                                       Netherlands, Portugal,
                                                       Sweden, Albania, Lithuania,
                                                       Latvia, Macedonia, Romania
                                                       and Slovenia
</TABLE>



                                      A-1.
<PAGE>

                                    EXHIBIT B

                               COUNTRIES OF EUROPE


<TABLE>
<S>                       <C>                           <C>                       <C>
ANDORRA                    AUSTRIA                       BELGIUM                   BOSNIA
BULGARIA                   CROATIA                       CYPRUS                    CZECH REPUBLIC
DENMARK                    ESTONIA                       FINLAND                   FRANCE
GERMANY                    GREECE                        HUNGARY                   ICELAND
IRELAND                    ITALY                         LATVIA                    LIECHTENSTEIN
LITHUANIA                  LUXEMBOURG                    MONACO                    NETHERLANDS
NORWAY                     POLAND                        PORTUGAL                  ROMANIA
RUSSIAN REPUBLIC           SAN MARINO                    SERBIA                    SLOVAKIA
SLOVENIA                   SPAIN                         SWEDEN                    SWITZERLAND
TURKEY                     UNITED KINGDOM                VATICAN CITY              YUGOSLAVIA
</TABLE>



                                      B-1.
<PAGE>

                                    EXHIBIT C

                                DEVELOPMENT PLAN

[*]


----------
* Confidential Treatment Requested.

                                      C-1.
<PAGE>

                                    EXHIBIT D

                             CORIXA CLINICAL TRIALS


<TABLE>
<CAPTION>
                                                                           ENROLLED
                           SITE                                           (4/30/01)/
CPI PROTOCOL NUMBER      (US, EU)          TITLE          OBJECTIVE         TARGET        STATUS    START ACCRUAL    END ACCRUAL
-------------------      --------          -----          ---------       ----------      ------    -------------    -----------
<S>                     <C>                <C>           <C>              <C>            <C>        <C>             <C>


[*]

</TABLE>


----------
* Confidential Treatment Requested.


                                      D-1.

<PAGE>

                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>        <C>                                                                                                 <C>
1.          DEFINITIONS..........................................................................................1
            1.1         "Affiliate"..............................................................................1
            1.2         "Amersham Iodine I 131 Tositumomab"......................................................2
            1.3         "Amersham Matter"........................................................................2
            1.4         "Annual Net Sales".......................................................................2
            1.5         "BLA"....................................................................................2
            1.6         "Clinical Trial".........................................................................2
            1.7         "Clinical Trial Costs"...................................................................2
            1.8         "Collaboration Steering Committee".......................................................2
            1.9         "Controlled".............................................................................2
            1.10        "Corixa".................................................................................2
            1.11        "Corixa Intellectual Property Rights"....................................................3
            1.12        "Corixa Iodine I 131 Tositumomab"........................................................3
            1.13        "Corixa Matter"..........................................................................3
            1.14        "Corixa Territory".......................................................................3
            1.15        "Cross-Territory Clinical Trial".........................................................3
            1.16        "Dana Farber Agreements".................................................................3
            1.17        "Development Budget".....................................................................3
            1.18        "Development Plan".......................................................................4
            1.19        "Diligent Efforts".......................................................................4
            1.20        "Effective Date".........................................................................4
            1.21        "European Facility"......................................................................4
            1.22        "FD&C Act"...............................................................................4
            1.23        "FDA"....................................................................................4
            1.24        "Field"..................................................................................4
            1.25        "First Commercial Sale"..................................................................4
            1.26        "FTE Rate"...............................................................................4
            1.27        "Fully Allocated Cost"...................................................................4
            1.28        "Good Manufacturing Practice"............................................................5
            1.29        "Information"............................................................................5
</TABLE>

                                      -i-



<PAGE>

                                TABLE OF CONTENTS
                                   (continued)


<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>        <C>                                                                                                 <C>
            1.30        "Initial Approval".......................................................................6
            1.31        "Initial Approval Clinical Trials".......................................................6
            1.32        "Initial Approval Trial Costs"...........................................................6
            1.33        "Initial Development Plan"...............................................................6
            1.34        "Initial Regulatory Filings".............................................................6
            1.35        "Intellectual Property Rights"...........................................................6
            1.36        "Invention"..............................................................................7
            1.37        "Iodine I 131 Tositumomab"...............................................................7
            1.38        "Joint Commercialization Committee"......................................................7
            1.39        "Joint Development Committee.............................................................7
            1.40        "Joint Other Inventions".................................................................7
            1.41        "Know-How"...............................................................................7
            1.42        "MAA"....................................................................................7
            1.43        "Major Market Countries".................................................................7
            1.44        "Marketing Plan".........................................................................7
            1.45        "Michigan Agreement".....................................................................7
            1.46        "Net Sales"..............................................................................8
            1.47        "Other Invention"........................................................................8
            1.48        "Patent".................................................................................8
            1.49        "Pricing Approval".......................................................................8
            1.50        "Product"................................................................................8
            1.51        "Product Improvement"....................................................................8
            1.52        "Product Invention"......................................................................8
            1.53        "QA/QC Costs"............................................................................8
            1.54        "Regulatory Approval"....................................................................9
            1.55        "Regulatory Filing"......................................................................9
            1.56        "Second Indication"......................................................................9
            1.57        "Sole Other Inventions"..................................................................9
            1.58        "Specifications".........................................................................9
            1.59        "Stock Purchase Agreement"...............................................................9
</TABLE>


                                      -ii-

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)


<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>        <C>                                                                                                 <C>
            1.60        "Subsequent Clinical Trial"..............................................................9
            1.61        "Subsequent Development Plan"............................................................9
            1.62        "Subsequent Regulatory Filings"..........................................................9
            1.63        "Territory".............................................................................10
            1.64        "Third Party"...........................................................................10
            1.65        "Tositumomab"...........................................................................10

2.          LICENSES AND EXCLUSIVITY............................................................................10
            2.1         Licenses to Amersham....................................................................10
            2.2         Negative Covenant.......................................................................11
            2.3         License to Corixa.......................................................................11
            2.4         Negative Covenant.......................................................................11
            2.5         Covenant Not to Sue.....................................................................11
            2.6         Existing Third Party Licenses...........................................................12
            2.7         New Third Party Licenses................................................................12
            2.8         Exclusivity.............................................................................13
            2.9         U.N. Convention Not Applicable..........................................................13

3.          GOVERNANCE STRUCTURES...............................................................................13
            3.1         Collaboration Steering Committee (CSC)..................................................13
            3.2         Joint Development Committee (JDC).......................................................14
            3.3         Joint Commercialization Committee (JCC).................................................16

4.          DEVELOPMENT; GOVERNANCE; DILIGENCE..................................................................17
            4.1         Overview................................................................................17
            4.2         Initial Development Plan................................................................18
            4.3         Updates to Development Plan.............................................................18
            4.4         Development Budget......................................................................19
            4.5         Responsibility, Approval and Designation of Clinical Trials.............................19
            4.6         Forecasts of Supply for Initial Approval Clinical Trial.................................19
            4.7         Development Diligence...................................................................19

5.          CLINICAL TRIALS AND REGULATORY ISSUES...............................................................20
            5.1         Transfer of Pre-existing Files and Data.................................................20
</TABLE>


                                     -iii-

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)


<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>        <C>                                                                                                 <C>
            5.2         Clinical Trials Solely in the Territory.................................................21
            5.3         Clinical Trials Solely in the Corixa Territory..........................................22
            5.4         Cross-Territory Clinical Trials.........................................................22
            5.5         Clinical Trial Costs Audit..............................................................23
            5.6         Initial Regulatory Filings..............................................................23
            5.7         Transfer of Initial Regulatory Filings..................................................24
            5.8         Subsequent Regulatory Filings...........................................................24
            5.9         Pricing Approvals and Pricing...........................................................24
            5.10        Updates.................................................................................25
            5.11        Records.................................................................................25

6.          REGULATORY COMPLIANCE...............................................................................25
            6.1         Adverse Event Reporting.................................................................25
            6.2         Compliance..............................................................................25
            6.3         Product Complaints......................................................................26
            6.4         Product Recall..........................................................................26

7.          MARKETING...........................................................................................26
            7.1         Marketing Plan..........................................................................26
            7.2         Diligence...............................................................................27
            7.3         Reporting...............................................................................27

8.          ECONOMICS...........................................................................................27
            8.1         Equity Investment.......................................................................27
            8.2         Milestones..............................................................................27
            8.3         Royalties...............................................................................28
            8.4         Independent Manufacture Royalties.......................................................28
            8.5         Quarterly Payments and Payment Reports..................................................29
            8.6         Payment Method..........................................................................29
            8.7         Invoicing of Initial Approval Trial Costs...............................................29
            8.8         Taxes...................................................................................29
            8.9         Currency of Payment.....................................................................29
            8.10        Blocked Currency........................................................................29
</TABLE>


                                      -iv-

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)


<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>        <C>                                                                                                 <C>
            8.11        Sublicenses.............................................................................29
            8.12        Foreign Exchange........................................................................29
            8.13        Records; Inspection.....................................................................29
            8.14        Late Payment Penalty....................................................................30

9.          INTELLECTUAL PROPERTY...............................................................................30
            9.1         Ownership...............................................................................30
            9.2         Disclosure..............................................................................30
            9.3         Patent Prosecution and Maintenance; Abandonment.........................................30
            9.4         Enforcement of Patent Rights............................................................31
            9.5         Defense of Third Party Claims...........................................................31
            9.6         Trademarks..............................................................................32

10.         CONFIDENTIALITY.....................................................................................32
            10.1        Nondisclosure of Confidential Information...............................................32
            10.2        Exceptions..............................................................................32
            10.3        Authorized Disclosure...................................................................32
            10.4        Termination of Prior Agreements.........................................................33
            10.5        Publicity...............................................................................33
            10.6        Publications............................................................................33

11.         TERM AND TERMINATION................................................................................34
            11.1        Term....................................................................................34
            11.2        Amendment of Territory..................................................................34
            11.3        Termination for Material Breach.........................................................34
            11.4        Termination By Amersham.................................................................35
            11.5        Termination by Corixa...................................................................35
            11.6        Termination by Mutual Agreement.........................................................36
            11.7        Effect of Termination; Survival.........................................................36

12.         REPRESENTATIONS AND COVENANTS.......................................................................37
            12.1        Mutual Authority........................................................................37
            12.2        Performance by Affiliates...............................................................37

13.         INDEMNIFICATION AND LIMITATION OF LIABILITY.........................................................38
</TABLE>


                                      -v-

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)


<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>        <C>                                                                                                 <C>
            13.1        Indemnification.........................................................................38
            13.2        Limitation of Liability.................................................................38
            13.3        Insurance...............................................................................39

14.         MISCELLANEOUS.......................................................................................39
            14.1        Dispute Resolution......................................................................39
            14.2        Governing Law...........................................................................39
            14.3        Patents and Trademarks..................................................................40
            14.4        Entire Agreement; Amendment.............................................................40
            14.5        Export Control..........................................................................40
            14.6        Bankruptcy..............................................................................40
            14.7        Force Majeure...........................................................................41
            14.8        Notices.................................................................................42
            14.9        Consents Not Unreasonably Withheld or Delayed...........................................42
            14.10       Maintenance of Records..................................................................42
            14.11       United States Dollars...................................................................42
            14.12       No Strict Construction..................................................................43
            14.13       English.................................................................................43
            14.14       Assignment..............................................................................43
            14.15       Hardship................................................................................43
            14.16       Electronic Data Interchange.............................................................43
            14.17       Counterparts............................................................................43
            14.18       Further Actions.........................................................................43
            14.19       Severability............................................................................43
            14.20       Ambiguities.............................................................................44
            14.21       Headings................................................................................44
            14.22       No Waiver...............................................................................44
</TABLE>


                                      -vi-