Document:

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                                                                   Exhibit 10.1

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

              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.

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

        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.

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        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).

        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.

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        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 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 Corixa to Third Parties (including Third Party
licensors such as Dana Farber

* Confidential treatment requested.

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and University of Michigan), for the manufacture or supply to Amersham of such
Tositumomab or Corixa Iodine I 131 Tositumomab, including, but not limited to,
the transfer price for such antibody, cancellation payments (limited to Amersham
cancellations), payments related to failed batches (to the extent not otherwise
charged to Amersham pursuant to this Agreement), readiness payments, and
facilities charges owed to such Third Parties, plus

               (b) QA/QC 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 freight
and tariffs associated with transporting Tositumomab or Corixa Iodine I 131
Tositumomab from the source of manufacture to the end user, inclusive of interim
points of delivery, but excluding any such costs which are separately invoiced
to a customer, plus

               (e) The cost of Corixa employees engaged in Tositumomab or Corixa
Iodine I 131 Tositumomab manufacturing-related activities, including, without
limitation, employees engaged in oversight of manufacture by Third Parties, plus

               (f) A reasonable allocation, with respect to such Tositumomab or
Corixa Iodine I 131 Tositumomab, of Corixa's: (i) indirect labor (to the extent
not previously included in (d) or (e)), (ii) administrative costs, and (iii)
facilities costs including electricity, water, sewer, waste disposal, property
taxes, and depreciation over the expected life of buildings and equipment. 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.

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        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;

               (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 direct FTE 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 indirect FTE costs and non-FTE internal costs, including without
limitation overhead expenses, 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 manufacture or purification of monoclonal
antibodies, 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.

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        1.37 "IODINE I 131 TOSITUMOMAB" shall mean any therapeutic, prophylactic
or palliative product containing or comprising the composition of matter
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).

        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 price adjustments,
billing errors, rejected goods, damaged goods and recall returns; (ii) credits,
rebates, charge-back and prime vendor rebates, fees, reimbursements or similar
payments granted or given to wholesalers and other distributors, buying groups,
health care insurance carriers, pharmacy benefit management companies, health
maintenance organizations or other institutions or health care organizations;
(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).

* Confidential treatment requested.

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        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.

        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
formulation, packaging, storage, administration or dosimetry of the Product but
does not pertain to radiolabeling 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 solely to, or
the sole use of which is limited 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 release and Product testing of Tositumomab and Corixa Iodine
I 131 Tositumomab, but only to the extent that such quality assurance and
quality control work is required by the FDA or other relevant regulatory
authorities. QA/QC Costs shall include a reasonable allocation of Corixa's
facility overhead, and shall include any allocation of the costs of establishing
or validating a facility or any costs of excess capacity directly 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.

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        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
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 products manufactured by or on behalf of
Corixa for use in markets in the Corixa Territory. 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 composition of matter that (i) has not
been conjugated with 131Iodine or any other isotope, molecule, compound or
moiety and (ii) was administered to patients in Corixa's clinical trial with
Protocol No. RIT-II-004 as referred to in

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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 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 prior written consent of Corixa and (ii) in all other countries in the
Territory, with prior written notification 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

* Confidential Treatment Requested

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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) 10 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.

        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.

                                       11
<PAGE>

        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 Amersham that its activities under this Agreement involving the Product
as formulated and administered as of the Effective Date 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 and deducted from
Amersham's Net Sales.

               (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 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 Corixa 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 Corixa 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
passed on to Amersham as part of the Fully Allocated Cost of such Tositumomab or
Corixa Iodine I 131 Tositumomab and such increase in Fully Allocated Cost shall
be deducted from Amersham's Net Sales.

               (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 Corixa 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 Corixa and shall not be passed on to
Amersham 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.

                                       12
<PAGE>

        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
antibody directed at CD20 (other than a Product and whether unconjugated or
conjugated to any isotope, molecule, compound or moiety) for the same indication
for which Corixa and/or Amersham plans to seek Initial Approval for a Product or
for which Amersham plans to seek, is seeking or has received any other
Regulatory Approval in the Territory for a Product, Amersham shall immediately
notify Corixa. Corixa may at any time thereafter, upon six 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.

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

                                       13
<PAGE>

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.

               (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.

                                       14
<PAGE>

               (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
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;

                                       15
<PAGE>

                      (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.

        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

                                       16
<PAGE>

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:

                      (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

                                       17
<PAGE>

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 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

                                       18
<PAGE>

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 Amersham employees performing work related to the Initial Approval
Clinical Trials who shall be considered FTEs for the purposes of calculating
Initial Approval Trial Costs and (ii) the amount to be paid by Corixa (as part
of the Initial Approval Trial Costs) for each such FTE as determined in
accordance with Section 1.32(c).

               (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 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.

                                       19
<PAGE>

               (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 clinical and
statistical descriptions, presentations and analyses) 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 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.

                                       20
<PAGE>

        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 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

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<PAGE>

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 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-

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<PAGE>

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 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

                                       23
<PAGE>

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 direct external costs and direct FTE 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:

               (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,

                                       24
<PAGE>

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.

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 its reasonable best 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.

                                       25
<PAGE>

        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 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

                                       26
<PAGE>

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:

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

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

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

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

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

               (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
$83 million and previous Annual Net Sales were less than $25 million, Amersham
shall make the milestone payments set forth in Sections 8.2(b), (c) and (d) (for
a total of $[*] million) 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:

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                                       27
<PAGE>

<TABLE>
<CAPTION>
CIRCUMSTANCE                                      RUNNING ROYALTY
------------                                      ---------------
<S>                                               <C>
(i)     there is on sale in such country an [*]   [*]% of Net Sales
that is marketed by [*] or a distributor or
licensee of [*] (other than [*])

(ii)    there is on sale in such country a [*]    [*]% of Net Sales
of [*] that is marketed by [*] which does not
[*] in such country [*]

(iii)   there is on sale in such country a [*]    [*]% of Net Sales
of [*] that is marketed by [*] which [*] in
such country [*]

(iv)    there is on sale in such country an [*]   [*]% of Net Sales
that is marketed by [*] which [*] in such
country from [*] was required to [*] by law,
regulation or governmental agency
</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 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

* Confidential Treatment Requested

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<PAGE>

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.

        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 three years following the end of the calendar quarter to which they
pertain. Such records will open for inspection during such three year period by
independent accountants, solely for the purpose of verifying payment statements

                                       29
<PAGE>

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 fourteen (14) 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 two (2) 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
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 an anti-CD20 antibody product.

        9.2 DISCLOSURE. Amersham shall submit a written report to Corixa within
60 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.

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<PAGE>

        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 thirty (30)
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 sixty (60) 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 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

                                       31
<PAGE>

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.

        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;

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<PAGE>

               (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.

        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

                                       33
<PAGE>

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 amendment will be six 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 sixty (60) days to either cure such breach or, if cure cannot be
reasonably effected within such sixty (60) 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 fifteen (15) 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 60-day 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 thirty (30) 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

                                       34
<PAGE>

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 thirty (30) 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.

        11.4 TERMINATION BY AMERSHAM.

               (a) Amersham shall have the right to terminate this Agreement
upon thirty (30) 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 six (6) 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 thirty (30) 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
thirty (30) 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
thirty (30) 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.

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<PAGE>

        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 60 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

                             (1) Amersham shall also supply, for thirty-six (36)
months after such termination, Amersham Iodine I 131 Tositumomab to Corixa at
Amersham's fully burdened manufacturing cost determined in accordance with the
terms of the Supply Agreement;

                             (2) At its sole discretion, Corixa may extend, by
eighteen (18) 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 18-month extension (if any), Corixa
shall pay Amersham a supply price not to exceed Amersham's fully burdened
manufacturing cost(1) that are directly attributable to the conversion of
Tositumomab to Amersham Iodine I 131 Tositumomab 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 Amersham's fully burdened manufacturing cost that are
directly attributable to the conversion of Tositumomab to Amersham Iodine I 131
Tositumomab 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.

(1) Such cost shall be determined in accordance with the terms of the Supply
Agreement.

* Confidential Treatment Requested

                                       36
<PAGE>

               (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, 2003 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 ninety (90)
days, for reasons other than force majeure, routine equipment maintenance,
ordinary course batch failures or other causes occurring in the normal course of
manufacturing to supply Amersham Iodine I 131 Tositumomab to Corixa during the
36-month period set forth in Section 11.7(b)(ii)(1), then Corixa shall have the
right solely during the four (4) months commencing (i) in the case of subsection
11.7(b)(i), on December 31, 2003 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 ninety (90) day period described in subsection
11.7(b)(ii), as applicable, to require Amersham to pay Corixa a termination fee
of three million dollars ($3 million), which fee shall be payable by Amersham
within thirty (30) 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 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 four (4) 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 $3 million 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.

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<PAGE>

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).

               (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 Two U.S.
Million Dollars (U.S. $2,000,000) per occurrence (or claim) and Six U.S.

                                       38
<PAGE>

Million Dollars (U.S. $6,000,000) annual aggregate limit of liability, and after
the First Commercial Sale in the Territory shall always maintain product
liability insurance with a minimum of Ten Million U.S Dollars (U.S. $10,000,000)
per occurrence (or claim) and Twenty U.S. Million Dollars (U.S. $20,000,000)
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 Two
U.S. Million Dollars (U.S. $2,000,000) per occurrence (or claim) and Six U.S.
Million Dollars (U.S. $6,000,000) 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.

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

                                       39
<PAGE>

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.

        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

                                       40
<PAGE>

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 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.

                                       41
<PAGE>

               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

               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.

                                       42
<PAGE>

        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.

        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.

                                       43
<PAGE>

        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.

<TABLE>
<S>                                                <C>
AMERSHAM PLC                                       CORIXA CORPORATION

By:                                                By:
   -----------------------------------------          ----------------------------------------

Name:                                              Name:  Steven Gillis
     ---------------------------------------
Title:                                             Title: Chairman and Chief Executive Officer
      --------------------------------------
Date:                                              Date:
     ---------------------------------------            --------------------------------------
</TABLE>

                                       44
<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-003/01EP         98928875.8       6/3/98    Austria, Belgium, Cyprus,       Radioprotectant for
(Corixa owns)         Publication      Pub.      Switzerland & Liechtenstein,    Peptides Labeled
                      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-003/01NO         1999 5906        6/3/98    Norway                          Radioprotectant for
(Corixa owns)                                                                    Peptides Labeled
                                                                                 with Radioisotope

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

COUL-005/04EP         99955224.3 WO    6/4/99    Austria, Belgium, Cyprus,       Patient-Specific
(Corixa/UM            99/62565         Pub.      Switzerland & Liechtenstein,    Dosimetry
co-owners--license                     Date      Germany, Denmark, Spain,
to Corixa)                             12/9/99   Finland, France, United
                                                 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

A. OUTLINE

REGULATORY

        Under [*], several meetings have been held with various national Health
Authorities in Europe and with the EMEA. It was generally felt that the database
was [*]. It was also believed that a [*] with [*] was not necessary, but all of
the Health Authorities who were visited deferred to [*] to make the final call.
The outcome of these meetings identified that an [*] was targeted for late [*].
Subsequently, Amersham, in consultation with Corixa, believes that it is highly
likely that the European regulatory authorities for initial product approval
will [*]. Corixa has agreed to take full responsibility for conducting clinical
trials that will be required to gain initial regulatory approval in Europe.

        Upon execution of this Agreement, Corixa will need to notify EMEA that
Corixa or its designee will be the [*] instead of [*]. Corixa will then notify
the EMEA that it intends to [*] for [*].

        In parallel with this effort, Corixa will begin to prepare for
submission of an [*]. This application will rely on the documentation contained
in the [*] submitted to the [*]. This [*] is currently under review by the [*].

        In addition to this, other activities will be taking place in parallel
with the above activities. Amersham will designate members to serve on the
Collaboration Steering Committee, the Joint Commercialization Committee and the
Joint Development Committee. The representatives on these committees will
include but not be limited to regulatory, manufacturing, commercial marketing,
and business development. Further activities by the appropriate parties will
include:

-     Determination of a decision to submit an [*] to EMEA,

-     Update the [*], and any other documents that should include [*],

-     A [*] will be developed,

-     Determination and, if necessary, conduct of [*],

-     An [*] on a [*] will be made,

-     A Qualified Person to perform [*] using the [*] supplied from [*] will be
      made, and

* Confidential Treatment Requested

                                       C-1
<PAGE>

-     Drafting of final labeling and packaging.

In addition Amersham will begin to draft a mechanism for reporting adverse
events and product complaints in cooperation with Corixa. A full Development
Plan will be drafted by the Parties for review by the Joint Development
Committee within 60 days after the receipt of the data from Corixa.

CLINICAL

        As a first priority and in parallel with regulatory activities, Corixa
will begin to draft a study design for the conduct of [*] for the indication of
[*]. The end point for this trial will be [*]. The final development plan will
be approved by the JDC. The specific aims and endpoints of this trial will be
worked out by Corixa; this input may be done in consultation with the CPMP/EMEA.

        In addition to the initial [*], Amersham, in consultation with the Joint
Development Committee will plan a [*]. This trial will have the objective of
establishing [*]. Within this plan, consideration will be given to establishment
of a [*]. The endpoints of these trials will be worked out in consultation with
Corixa.

        In addition a prioritized list of clinical development needed to expand
approved labeling will be constructed. This list will direct the next phases of
clinical development. This effort will be directed by Amersham's commercial
marketing.

        If feedback from the EMEA review indicates the necessity to conduct
other clinical programs besides [*], these will be given priority. The endpoints
of these trials will be worked out by Clinical Research, Regulatory Affairs, and
Commercial Marketing.

MANUFACTURING

        Amersham will be responsible for all activities associated with the
development, validation and process for radiolabeling tositumomab with I131 for
human use, as well as to provide Quality Assurance, Quality Control and
regulatory support services in order to commercialize tositumomab and
radiolabeled tositumomab with the shortest possible critical path.

        As a first priority Amersham will identify which of its [*] will be used
to establish [*] capability.

        As a part of the effort to establish radiolabeling process Amersham will
develop:

-     Technology transfer of the radiolabeling process to the selected [*]
      facility

-     QC methods and technology transfer

-     Validate these methods

* Confidential Treatment Requested

                                       C-2
<PAGE>

-     [*] of [*] with that of the [*] (as approved by the FDA)

-     If necessary Amersham will make applications with all relevant regulatory
      authorities for [*]

-     Establish, if necessary, a distribution method for the distribution of
      [*] product

-     Establish a system for [*] of [*]

-     Establish a mechanism for the [*] through Corixa.

        Commercial production for radiolabelled product is expected to begin in
the [*] or a date to be determined by the Parties.

B. INITIAL DEVELOPMENT PLAN [TO BE DEVELOPED FOLLOWING EXECUTION OF THIS
AGREEMENT.]

* Confidential Treatment Requested

                                       C-3

<PAGE>

                                    EXHIBIT D

                             CORIXA CLINICAL TRIALS

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

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]
</TABLE>
------------
* Confidential Treatment Requested

                                       D-1

<PAGE>

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

                                      [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

                                      [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

</TABLE>

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

                                       D-2
<PAGE>

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

                                         [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

                                         [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

                                         [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

                                         [*]
</TABLE>

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

                                       D-3
<PAGE>

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

                                         [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

                                         [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]

[*]           [*]          [*]                             [*]                 [*]         [*]         [*]             [*]
</TABLE>

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

                                       D-4
<PAGE>

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

                                         [*]

[*]            [*]         [*]                             [*]                  [*]        [*]          [*]            [*]
</TABLE>

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

                                       D-5
<PAGE>

                                TABLE OF CONTENTS
<TABLE>
<CAPTION>
                                                                                          PAGE
<S>                                                                                       <C>
1.      DEFINITIONS.........................................................................1

        1.1    "Affiliate"..................................................................1

        1.2    "Amersham Iodine I 131 Tositumomab"..........................................1

        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".....................................................................3

        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".........................................................4

        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".......................................................5

        1.28   "Good Manufacturing Practice"................................................5

        1.29   "Information"................................................................6
</TABLE>

                                       -i-
<PAGE>

                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                          PAGE
<S>                                                                                       <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".................................................7

        1.35   "Intellectual Property Rights"...............................................7

        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"........................................................................8

        1.43   "Major Market Countries".....................................................8

        1.44   "Marketing Plan".............................................................8

        1.45   "Michigan Agreement".........................................................8

        1.46   "Net Sales"..................................................................8

        1.47   "Other Invention"............................................................8

        1.48   "Patent".....................................................................8

        1.49   "Pricing Approval"...........................................................9

        1.50   "Product"....................................................................9

        1.51   "Product Improvement"........................................................9

        1.52   "Product Invention"..........................................................9

        1.53   "QA/QC Costs"................................................................9

        1.54   "Regulatory Approval"........................................................9

        1.55   "Regulatory Filing"..........................................................9

        1.56   "Second Indication"..........................................................9

        1.57   "Sole Other Inventions"......................................................9

        1.58   "Specifications"............................................................10

        1.59   "Stock Purchase Agreement"..................................................10
</TABLE>

                                      -ii-
<PAGE>

                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                          PAGE
<S>                                                                                       <C>
        1.60   "Subsequent Clinical Trial".................................................10

        1.61   "Subsequent Development Plan"...............................................10

        1.62   "Subsequent Regulatory Filings".............................................10

        1.63   "Territory".................................................................10

        1.64   "Third Party"...............................................................10

        1.65   "Tositumomab"...............................................................10

2.      LICENSES AND EXCLUSIVITY...........................................................11

        2.1    Licenses to Amersham........................................................11

        2.2    Negative Covenant...........................................................12

        2.3    License to Corixa...........................................................12

        2.4    Negative Covenant...........................................................12

        2.5    Covenant Not to Sue.........................................................12

        2.6    Existing Third Party Licenses...............................................12

        2.7    New Third Party Licenses....................................................13

        2.8    Exclusivity.................................................................14

        2.9    U.N. Convention Not Applicable..............................................14

3.      GOVERNANCE STRUCTURES..............................................................14

        3.1    Collaboration Steering Committee (CSC)......................................14

        3.2    Joint Development Committee (JDC)...........................................16

        3.3    Joint Commercialization Committee (JCC).....................................17

4.      DEVELOPMENT; GOVERNANCE; DILIGENCE.................................................19

        4.1    Overview....................................................................19

        4.2    Initial Development Plan....................................................19

        4.3    Updates to Development Plan.................................................20

        4.4    Development Budget..........................................................20

        4.5    Responsibility, Approval and Designation of Clinical Trials.................21

        4.6    Forecasts of Supply for Initial Approval Clinical Trial.....................21

        4.7    Development Diligence.......................................................21

5.      CLINICAL TRIALS AND REGULATORY ISSUES..............................................22

        5.1    Transfer of Pre-existing Files and Data.....................................22
</TABLE>

                                      -iii-
<PAGE>

                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                          PAGE
<S>                                                                                       <C>
        5.2    Clinical Trials Solely in the Territory.....................................22

        5.3    Clinical Trials Solely in the Corixa Territory..............................24

        5.4    Cross-Territory Clinical Trials.............................................24

        5.5    Clinical Trial Costs Audit..................................................25

        5.6    Initial Regulatory Filings..................................................25

        5.7    Transfer of Initial Regulatory Filings......................................26

        5.8    Subsequent Regulatory Filings...............................................26

        5.9    Pricing Approvals and Pricing...............................................26

        5.10   Updates.....................................................................27

        5.11   Records.....................................................................27

6.      REGULATORY COMPLIANCE..............................................................27

        6.1    Adverse Event Reporting.....................................................27

        6.2    Compliance..................................................................28

        6.3    Product Complaints..........................................................28

        6.4    Product Recall..............................................................28

7.      MARKETING..........................................................................28

        7.1    Marketing Plan..............................................................28

        7.2    Diligence...................................................................29

        7.3    Reporting...................................................................29

8.      ECONOMICS..........................................................................29

        8.1    Equity Investment...........................................................29

        8.2    Milestones..................................................................29

        8.3    Royalties...................................................................30

        8.4    Independent Manufacture Royalties...........................................31

        8.5    Quarterly Payments and Payment Reports......................................31

        8.6    Payment Method..............................................................31

        8.7    Invoicing of Initial Approval Trial Costs...................................32

        8.8    Taxes.......................................................................32

        8.9    Currency of Payment.........................................................32

        8.10   Blocked Currency............................................................32
</TABLE>

                                      -iv-
<PAGE>

                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                          PAGE
<S>                                                                                       <C>
        8.11   Sublicenses.................................................................32

        8.12   Foreign Exchange............................................................32

        8.13   Records; Inspection.........................................................32

        8.14   Late Payment Penalty........................................................33

9.      INTELLECTUAL PROPERTY..............................................................33

        9.1    Ownership...................................................................33

        9.2    Disclosure..................................................................33

        9.3    Patent Prosecution and Maintenance; Abandonment.............................33

        9.4    Enforcement of Patent Rights................................................34

        9.5    Defense of Third Party Claims...............................................34

        9.6    Trademarks..................................................................35

10.     CONFIDENTIALITY....................................................................35

        10.1   Nondisclosure of Confidential Information...................................35

        10.2   Exceptions..................................................................35

        10.3   Authorized Disclosure.......................................................36

        10.4   Termination of Prior Agreements.............................................37

        10.5   Publicity...................................................................37

        10.6   Publications................................................................37

11.     TERM AND TERMINATION...............................................................37

        11.1   Term........................................................................37

        11.2   Amendment of Territory......................................................37

        11.3   Termination for Material Breach.............................................38

        11.4   Termination By Amersham.....................................................39

        11.5   Termination by Corixa.......................................................39

        11.6   Termination by Mutual Agreement.............................................39

        11.7   Effect of Termination; Survival.............................................39

12.     REPRESENTATIONS AND COVENANTS......................................................41

        12.1   Mutual Authority............................................................41

        12.2   Performance by Affiliates...................................................41

13.     INDEMNIFICATION AND LIMITATION OF LIABILITY........................................41
</TABLE>

                                       -v-
<PAGE>

                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                                          PAGE
<S>                                                                                       <C>
        13.1   Indemnification.............................................................41

        13.2   Limitation of Liability.....................................................42

        13.3   Insurance...................................................................42

14.     MISCELLANEOUS......................................................................43

        14.1   Dispute Resolution..........................................................43

        14.2   Governing Law...............................................................43

        14.3   Patents and Trademarks......................................................43

        14.4   Entire Agreement; Amendment.................................................44

        14.5   Export Control..............................................................44

        14.6   Bankruptcy..................................................................44

        14.7   Force Majeure...............................................................45

        14.8   Notices.....................................................................45

        14.9   Consents Not Unreasonably Withheld or Delayed...............................46

        14.10  Maintenance of Records......................................................46

        14.11  United States Dollars.......................................................47

        14.12  No Strict Construction......................................................47

        14.13  English.....................................................................47

        14.14  Assignment..................................................................47

        14.15  Hardship....................................................................47

        14.16  Electronic Data Interchange.................................................47

        14.17  Counterparts................................................................47

        14.18  Further Actions.............................................................47

        14.19  Severability................................................................47

        14.20  Ambiguities.................................................................48

        14.21  Headings....................................................................48

        14.22  No Waiver...................................................................48
</TABLE>

                                      -vi-<PAGE>
                                                                   Exhibit 10.46

                      AMENDMENT NO. 1 TO CREDIT AGREEMENT

THIS AMENDMENT NO. 1 TO CREDIT AGREEMENT (this "Amendment"), dated as of April
15, 2002, is entered into between Bank of America, N.A. ("Lender") and Meade
Instruments Corp., a Delaware corporation ("Borrower"), with reference to the
following facts:

                                    RECITALS

A.      Lender and Borrower are parties to that certain Credit Agreement, dated
        as of September 24, 2001 (the "Credit Agreement"), pursuant to which
        Lender provided Borrower with certain credit facilities.

B.      Borrower and Lender wish to amend the Credit Agreement as described
        below.

NOW, THEREFORE, the parties hereby agree as follows:

1.      Defined Terms. Any and all initially capitalized terms used in this
        Amendment (including, without limitation, in the recitals hereto)
        without definition shall have the respective meanings specified in the
        Credit Agreement.

2.      Amendment to Section 1.1. Section 1.1 of the Credit Agreement is amended
        to read in its entirety as follows:

               Subject to all of the terms and conditions of this Agreement, the
               Lender agrees to make available a total credit facility of up to
               $27,100,000 (the "Total Facility") to the Borrower from time to
               time during the term of this Agreement. The Total Facility shall
               be composed of a revolving line of credit consisting of Revolving
               Loans and Letters of Credit and the Term Loan described herein.
               Notwithstanding any term of this Agreement to the contrary,
               Borrower agrees that while Pricing Level V (as used in the
               definition of Applicable Margin) is in effect, Borrower may not
               request any new LIBOR Rate Loans. While Pricing Level V is in
               effect, any existing LIBOR Rate Loan will be converted into a
               Base Rate Loan upon conclusion of the Interest Period applicable
               to such LIBOR Rate Loan.

3.      Amendment to Section 7.22. Section 7.22 of the Credit Agreement is
        amended in its entirety to read as follows:

               7.22 Fixed Charge Coverage Ratio. The Borrower will maintain a
               Fixed Charge Coverage Ratio for each period of four consecutive
               fiscal quarters ending on the last day of each fiscal quarter set
               forth below of not less than the applicable ratio set forth
               below:

<TABLE>
<CAPTION>
                                                   Minimum Fixed
                      Fiscal Quarter Ending        Charge Coverage Ratio
                      ---------------------        ---------------------
                     <S>                          <C>
                      February 28, 2002            0.50 to 1.00

                      May 31, 2002                 0.50 to 1.00
</TABLE>

                                      -1-
<PAGE>

<TABLE>
                     <S>                          <C>
                      August 31, 2002              0.10 to 1.00

                      November 30, 2002 and
                      each Fiscal Quarter
                      ending thereafter            1.00 to 1.00

</TABLE>

4.      Amendment to Section 7.23. Section 7.23 of the Credit Agreement is
        amended in its entirety to read as follows:

               7.23 Adjusted Tangible Net Worth. Borrower will maintain Adjusted
               Tangible Net Worth of not less than the following amounts during
               the following periods:

<TABLE>
<CAPTION>
                                                   Minimum Adjusted
                      End of Month                 Tangible Net Worth
                      ---------------------        ---------------------
                     <S>                          <C>
                      Each month prior to
                      and including June 2002      $37,500,000

                      July 2002                    $38,000,000

                      August 2002                  $38,500,000

                      September 2002               $38,830,000

                      October 2002                 $39,383,000

                      November 2002 and each
                      month to and including
                      February 2003                $39,711,000

                      Each month after
                      February 2003                $39,711,000 plus 50% of positive
                                                   Net Income thereafter

</TABLE>

               "Net Income" means, with respect to any fiscal period of the
               Borrower, the Borrower's net income on a consolidated basis as
               determined in accordance with GAAP and reported on the Financial
               Statements for such period.

5.      Amendment to Section 7.25. Section 7.25 of the Credit Agreement is
        amended in its entirety to read as follows:

               7.25 US EBITDA. The Borrower will maintain US EBITDA for each
               period of four consecutive fiscal quarters ending on the last day
               of each fiscal quarter set forth below of not less than the
               applicable minimum US EBITDA set forth below:

<TABLE>
<CAPTION>
                     Fiscal Quarter Ending        Minimum US EBITDA
                     ---------------------        -------------------
                     <S>                          <C>
                      February 28, 2002            $2,000,000

</TABLE>

                                      -2-
<PAGE>

<TABLE>
                     <S>                          <C>
                      May 31, 2002                 $1,000,000

                      August 31, 2002               ($500,000)

                      November 30, 2002            $3,000,000

                      February 28, 2003            $3,075,000

                      May 31, 2003                 $3,250,000

                      August 31, 2003              $3,250,000

                      November 30, 2003            $3,500,000

                      February 29, 2004 and
                      each Fiscal Quarter
                      ending thereafter            $4,250,000
</TABLE>

6.      Amendments to Annex A. A definition for "Fixed Charge Coverage Ratio
        Shortfall Reserve" is added to Annex A of the Credit Agreement, and the
        definitions of "Applicable Margin", and "Maximum Revolver Amount" and
        "Reserves", as set forth in Annex A to the Credit Agreement are amended
        to read as follows:

               "Applicable Margin" means

               (i)    with respect to Base Rate Revolving Loans, Base Rate Term
                      Loans, and all other Obligations (other than LIBOR Loans),
                      1%;

               (ii)   with respect to LIBOR Revolving Loans, 3 1/4%; and

               (iii)  with respect to LIBOR Term Loans, 3 1/2%.

               The Applicable Margins shall be adjusted (up or down)
               prospectively on a quarterly basis as determined by the
               Borrower's consolidated financial performance, commencing with
               the first day of the first calendar month that occurs more than 5
               days after required delivery to Lender of the Borrower's draft
               audited Financial Statements to Lender for the Fiscal Year ending
               February 28, 2002. In the event the draft audited Financial
               Statements are subsequently determined to be in error, then any
               resulting change in the Applicable Margin shall be made
               retroactively to the date when the incorrect Applicable Margin
               was utilized. Adjustments in Applicable Margins shall be
               determined by reference to the following grids:

<TABLE>
<CAPTION>
                      IF FIXED CHARGE
                      COVERAGE RATIO               PRICING LEVEL
                      --------------               -------------
                     <S>                          <C>
                      Greater than 1.50 to 1.00    Level I

                      Greater than 1.25 to 1.00
                      but equal to or less than
                      1.50 to 1.00                 Level II
</TABLE>

                                      -3-
<PAGE>

<TABLE>
                     <S>                          <C>
                      Greater than 1.00 to 1.00
                      but equal to or less than
                      1.25 to 1.00                 Level III

                      Greater than 0.75 to 1.00
                      but equal to or less than
                      1.00 to 1.00                 Level IV

                      Equal to or less than
                      0.75 to 1.00                 Level V
</TABLE>

                               APPLICABLE MARGINS

<TABLE>
<CAPTION>
                                                   LEVEL I  LEVEL II   LEVEL III   LEVEL IV   LEVEL V
                                                   -------  --------   ---------   --------   -------
                      <S>                          <C>      <C>        <C>         <C>       <C>
                      Base Rate Loans               0.25%     0.50%      0.75%      1.25%      1.50%
                      LIBOR Revolving Loans         2.50%     2.75%      3.00%      3.50%      Not Avail.
                      LIBOR Term Loans              3.50%     3.50%      3.50%      3.50%      Not Avail.
</TABLE>

               All adjustments in the Applicable Margins after February 28,
               2002, shall be implemented quarterly on a prospective basis,
               commencing with the first day of the first calendar month that
               occurs more than 5 days after the required date of delivery to
               the Lender of quarterly unaudited or annual draft audited (as
               applicable) Financial Statements evidencing the need for an
               adjustment. In the event the draft audited Financial Statements
               are subsequently determined to be in error, then any resulting
               change in the Applicable Margin shall be made retroactively to
               the date when the incorrect Applicable Margin was utilized.
               Concurrently with the delivery of those Financial Statements, the
               Borrower shall deliver to the Lender a certificate, signed by its
               chief financial officer, setting forth in reasonable detail the
               basis for the continuance of, or any change in, the Applicable
               Margins. Failure to timely deliver such Financial Statements
               shall, in addition to any other remedy provided for in this
               Agreement, result in an increase in the Applicable Margins to the
               highest level set forth in the foregoing grid, until the first
               day of the first calendar month following the delivery of those
               Financial Statements demonstrating that such an increase is not
               required. If a Default or Event of Default has occurred and is
               continuing at the time any reduction in the Applicable Margins is
               to be implemented, no reduction may occur until the first day of
               the first calendar month following the date on which such Default
               or Event of Default is waived or cured.

               "Fixed Charge Coverage Ratio Shortfall Reserve" means $1,000,000
               at any time the Fixed Charge Coverage Ratio is less than 1.25 to
               1 for the period of four consecutive fiscal quarters ending on
               the last day of the fiscal quarter immediately prior to such
               time.

               "Maximum Revolver Amount" means $25,000,000.

               "Reserves" means reserves that limit the availability of credit
               hereunder, consisting of reserves against Availability, Eligible
               Accounts or Eligible Inventory, established by Lender from time
               to time in Lender's reasonable credit judgment. Without limiting
               the generality of the foregoing, the following

                                      -4-
<PAGE>

               reserves shall be deemed to be a reasonable exercise of Lender's
               credit judgment: (a) Bank Product Reserves; (b) a reserve for
               accrued, unpaid interest on the Obligations; (c) reserves for
               rent at leased locations subject to statutory or contractual
               landlord liens; (d) the Slow Moving Reserve; (e) the Dilution
               Adjustment Reserve; (f) warehousemen's or bailees' charges; and
               (g) the Fixed Charge Coverage Ratio Shortfall Reserve.

7.      Waiver of Default -- Section 7.23. Compliance with Section 7.23 of the
        Credit Agreement (as in effect prior to this Amendment) is hereby waived
        in respect of Borrower complying with the Adjusted Tangible Net Worth
        requirement for the period from November 30, 2001 through January 31,
        2002.

8.      Waiver of Default -- Section 7.25. Compliance with Section 7.25 of the
        Credit Agreement (as in effect prior to this Amendment) is hereby waived
        in respect of Borrower complying with the US EBITDA requirement for the
        period from November 30, 2001 through January 31, 2002.

9.      No Other Waivers. The waivers contained in Section 7 and Section 8 of
        this Amendment are expressly limited to the facts and circumstances
        referred to therein and shall not operate as a waiver of or a consent to
        non-compliance with any other section of the Credit Agreement or any of
        the other Loan Documents. The waivers contained in Section 7 and Section
        8 are only effective for the specific instances, for the specific
        purposes and for the specific periods for which given.

10.     Representations and Warranties of Borrower. Borrower represents and
        warrants that: (a) after giving effect to the Amendment no Default or
        Event of Default exists as of the date of this Amendment; and (b) no
        Default or Event of Default will result as a consequence of the
        transactions contemplated by this Amendment.

11.     Conditions Precedent. The effectiveness of this Amendment shall be
        subject to the prior satisfaction of all of the following conditions:

        (a)    Execution and Delivery of this Amendment. Lender shall have
               received an original of this Amendment, duly executed by
               Borrower.

        (b)    Consent and Reaffirmation of Guarantors. Each Guarantor shall
               have confirmed the continuing validity and effectiveness of the
               Continuing Guaranty dated as of September 24, 2001, by executing
               and delivering to Lender its Consent and Reaffirmation of
               Continuing Guaranty in the form of Exhibit "A" attached to this
               Amendment.

        (c)    Execution and Delivery of Certificate of Resolution. The Agent
               shall have received an original Certificate of Resolution, in the
               form of Exhibit "B", duly executed by the Secretary of Borrower.

        (d)    Amendment Fee. Lender shall have received an amendment fee of
               $50,000 in immediately available funds. Borrower acknowledges and
               agrees that this amendment fee is fully earned and nonrefundable
               upon receipt by Lender. Borrower acknowledges and agrees that
               Lender may effect payment of this amendment fee by charging the
               full amount thereof to Borrower's revolving loan account as a
               $50,000 Revolving Loan under the Agreement.

        (e)    Execution and Delivery of Other Documents. Borrower shall have
               executed and delivered to the Agent such other documents and
               instruments as the Agent may require.

                                      -5-
<PAGE>

12.     Miscellaneous.

        (a)    Survival of Representations and Warranties. All representations
               and warranties made in the Credit Agreement or in any other
               document or documents relating thereto, including without
               limitation, any Loan Document furnished in connection with this
               Amendment, shall survive the execution and delivery of this
               Amendment and the other Loan Documents, and no investigation by
               Lender or any closing shall affect the representations and
               warranties or the right of Lender to rely thereon.

        (b)    Reference to Credit Agreement. The Credit Agreement, each of the
               other Loan Documents, and any and all other agreements, documents
               or instruments now or hereafter executed and delivered pursuant
               to the terms hereof, or pursuant to the terms of the Credit
               Agreement as amended hereby, are hereby amended so that any
               reference therein to the Credit Agreement shall mean a reference
               to the Credit Agreement as amended hereby.

        (c)    Credit Agreement Remains in Effect. The Credit Agreement and the
               other Loan Documents remain in full force and effect and Borrower
               ratifies and confirms its agreements and covenants contained
               therein. Borrower hereby confirms that, after giving effect to
               this Amendment, no Event of Default or Default exists as of such
               date.

        (d)    Severability. Any provision of this Amendment held by a court of
               competent jurisdiction to be invalid or unenforceable shall not
               impair or invalidate the remainder of this Amendment and the
               effect thereof shall be confined to the provision so held to be
               invalid or unenforceable.

        (e)    Applicable Law. This Amendment and all other Loan Documents
               executed pursuant hereto shall be deemed to have been made and to
               be performable in the State of California and shall be governed
               by and construed in accordance with the internal laws (as opposed
               to the conflict of law provisions) of the State of California.

        (f)    Successors and Assigns. This Amendment is binding upon and shall
               inure to the benefit of Lender and Borrower and their respective
               successors and assigns; provided, however, that Borrower may not
               assign or transfer any of its rights or obligations hereunder
               without the prior written consent of Lender.

        (g)    Counterparts. This Amendment may be executed in one or more
               counterparts, each of which when so executed shall be deemed to
               be an original, but all of which when taken together shall
               constitute one and the same instrument.

        (h)    Execution by Facsimile. Facsimile transmission of a signed
               original of this Amendment or retransmission of any signed
               facsimile transmission or of any Loan Document will be deemed the
               same as delivery of an original. At the request of any other
               party, each of the undersigned will confirm facsimile
               transmission by signing a duplicate original document.

        (i)    Headings. The headings, captions and arrangements used in this
               Amendment are for convenience only and shall not affect the
               interpretation of this Amendment.

        (j)    Expenses of Lender. Borrower agrees to pay on demand (i) all
               costs and expenses reasonably incurred by Lender in connection
               with the preparation, negotiation and execution of this Amendment
               and the other Loan Documents executed pursuant hereto and any and
               all subsequent amendments, modifications, and supplements hereto
               or thereto, including, without limitation, the costs and fees of
               Lender's legal counsel and the

                                      -6-
<PAGE>

               allocated cost of Lender's in-house counsel and (ii) all costs
               and expenses reasonably incurred by Lender in connection with the
               enforcement or preservation of any rights under the Credit
               Agreement, this Agreement or any other Loan Documents, including,
               without limitation, the costs and fees of Lender's legal counsel
               and the allocated cost of Lender's in-house counsel.

        (k)    Miscellaneous Terms. The term "or" is disjunctive; the term "and"
               is conjunctive. The term "shall" is mandatory; the term "may" is
               permissive. Masculine terms also apply to females; feminine terms
               also apply to males. The term "including" is by way of example
               and not limitation.

        (l)    NO ORAL AGREEMENTS. THIS AMENDMENT, TOGETHER WITH THE OTHER LOAN
               DOCUMENTS AS WRITTEN, REPRESENTS THE FINAL AGREEMENT BETWEEN
               LENDERS AND BORROWER AND MAY NOT BE CONTRADICTED BY EVIDENCE OF
               PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL AGREEMENTS OF THE
               PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN LENDERS
               AND BORROWER.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                      -7-
<PAGE>

IN WITNESS WHEREOF, the parties have entered into this Amendment by their
respective duly authorized officers as of the date first above written.

                                        LENDER:

                                        BANK OF AMERICA, N.A.

                                        By:        /s/ Todd Eggertsen
                                               -------------------------------

                                        Name:      Todd Eggertsen
                                               -------------------------------

                                        Title:     Assistant Vice President
                                               -------------------------------

                                        BORROWER:

                                        MEADE INSTRUMENTS CORP.,
                                        a Delaware corporation

                                        By:        /s/ Brent W. Christensen
                                               -------------------------------

                                        Name:      Brent W. Christensen
                                               -------------------------------

                                        Title:     Chief Financial Officer
                                               -------------------------------

                                      -8-

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