Document:

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                                                                   EXHIBIT 10.11

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                       COLLABORATION AND LICENSE AGREEMENT

                                 by and between

                                      WYETH
                acting through its Wyeth Pharmaceuticals Division

                                       and

                          TRUBION PHARMACEUTICALS, INC.

                                December 19, 2005

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                                TABLE OF CONTENTS

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1.  DEFINITIONS.............................................................  1

2.  LICENSES................................................................ 17
    2.1   Licenses to Wyeth................................................. 17
          2.1.1  Exclusive Licenses......................................... 17
          2.1.2  Retained Rights of Trubion................................. 17
    2.2   License to Trubion................................................ 17
    2.3   Exclusivity....................................................... 17
          2.3.1  CD20 Product Exclusivity................................... 18
          2.3.2  ***........................................................ 18
          2.3.3  Limitations................................................ 18
    2.4   Sublicensing...................................................... 19
    2.5   Direct Licenses to Affiliates..................................... 19
    2.6   Right of Reference................................................ 20
    2.7   Section 365(n) of Bankruptcy Code................................. 20
    2.8   No Implied Rights................................................. 21

3.  RESEARCH PROGRAM........................................................ 21
    3.1   Scope and Conduct of the Research Program......................... 21
    3.2   Designation of Targets............................................ 22
          3.2.1  Target Candidates.......................................... 22
          3.2.2  Released Targets........................................... 23
          3.2.3  Wyeth Targets.............................................. 24
          3.2.4  Excluded Targets........................................... 25
    3.3   Term and Termination of the Research Program...................... 27
          3.3.1  Research Term.............................................. 27
          3.3.2  Termination of Research Program by Wyeth................... 27
    3.4   Joint Research Committee.......................................... 28
          3.4.1  Composition................................................ 28
          3.4.2  Responsibilities........................................... 28
          3.4.3  Meetings................................................... 28
          3.4.4  Voting..................................................... 28
          3.4.5  Dispute Resolution......................................... 28
          3.4.6  Minutes.................................................... 29
    3.5   Research Plan..................................................... 29
    3.6   Funding of the Research Program................................... 29
          3.6.1  Research Funding........................................... 29
          3.6.2  Reimbursement Payments..................................... 30
          3.6.3  Records and Audits......................................... 30
    3.7   Data and Deliverables............................................. 31
    3.8   Alliance Managers................................................. 32

4.  PRODUCT DEVELOPMENT, MANUFACTURING, COMMERCIALIZATION AND REGULATORY
    MATTERS................................................................. 32
    4.1   Product Development............................................... 32
    4.2   Transfer of Product Data and Filings.............................. 33
    4.3   Regulatory Approvals.............................................. 33
    4.4   Regulatory Reporting.............................................. 34
    4.5   Progress Reports.................................................. 34
    4.6   CD20 Product Development.......................................... 35
    4.7   Joint Development Committee....................................... 36
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    4.8   Joint Project Team; Development Plan...........................    36
    4.9   Manufacturing..................................................    37
    4.10  Commercialization..............................................    37
    4.11  Co-Promotion Option............................................    38
    4.12  Co-Promotion Committee.........................................    38
    4.13  Co-Branding....................................................    39
    4.14  Marking........................................................    39

5.  CONSIDERATION........................................................    39
    5.1   Initial Research and Development Expense Payment...............    39
    5.2   Equity.........................................................    39
    5.3   Additional Research and Development Expense Payments...........    39
    5.4   Royalties......................................................    39
          5.4.1  Product Royalties.......................................    39
          5.4.2  CD20 Product Royalties..................................    40
          5.4.3  ***.....................................................    42
          5.4.4  Other Product Royalties.................................    44
          5.4.5  Expiration of Royalty Period............................    45
          5.4.6  Royalty Adjustments.....................................    46
    5.5   Reports and Payments...........................................    46
          5.5.1  Cumulative Royalties....................................    46
          5.5.2  Royalty Statements and Payments.........................    47
          5.5.3  Taxes and Withholding...................................    47
          5.5.4  Currency................................................    48
          5.5.5  Additional Provisions Relating to Royalties.............    48
          5.5.6  Interest on Past Due Payments...........................    48
    5.6   Maintenance of Records; Audits.................................    48
          5.6.1  Record Keeping..........................................    48
          5.6.2  Audits..................................................    49
          5.6.3  Underpayments/Overpayments..............................    49
          5.6.4  Confidentiality.........................................    49

6.  INTELLECTUAL PROPERTY................................................    50
    6.1   Inventions; Joint Patent Committee.............................    50
          6.1.1  Ownership and Inventorship..............................    50
          6.1.2  SMIP Improvements.......................................    50
          6.1.3  Joint Patent Committee..................................    51
    6.2   Patent Rights..................................................    52
          6.2.1  Filing, Prosecution and Maintenance of Patent Rights....    52
          6.2.2  Enforcement of Patent Rights............................    59
          6.2.3  Infringement and Third Party Licenses...................    62
          6.2.4  Patent Certifications...................................    64
          6.2.5  Patent Term Restoration.................................    64
    6.3   Trademarks.....................................................    64

7.  CONFIDENTIALITY......................................................    65
    7.1   Confidentiality................................................    65
    7.2   Authorized Disclosure and Use..................................    65
          7.2.1  Disclosure..............................................    65
          7.2.2  Use.....................................................    66
    7.3   SEC Filings....................................................    67
    7.4   Public Announcements; Publications.............................    67
          7.4.1  Coordination............................................    67
          7.4.2  Announcements...........................................    67
          7.4.3  Publications............................................    67
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8.  REPRESENTATIONS AND WARRANTIES.......................................    68
    8.1   Representations and Warranties of Each Party...................    68
    8.2   Additional Representations and Warranties of Trubion...........    69
    8.3   Mutual Covenant................................................    70
    8.4   Additional Covenants of Trubion................................    70
    8.5   Representation by Legal Counsel................................    70
    8.6   No Inconsistent Agreements.....................................    70
    8.7   Disclaimer.....................................................    70

9.  GOVERNMENT APPROVALS; TERM AND TERMINATION...........................    71
    9.1   HSR Filing.....................................................    71
    9.2   Other Government Approvals.....................................    71
    9.3   Term...........................................................    71
    9.4   Termination Upon HSR Denial....................................    71
    9.5   Material Breach................................................    72
    9.6   Termination by Wyeth...........................................    72
          9.6.1  Termination Without Cause...............................    73
          9.6.2  Termination for a Material Safety or Regulatory Issue...    73
    9.7   Effects of Termination.........................................    73
          9.7.1  Effect of Termination by Wyeth for Cause................    73
          9.7.2  Effect of Termination by Trubion for Cause..............    77
          9.7.3  Effect of Termination by Wyeth Without Cause............    80
          9.7.4  Effect of Termination by Wyeth for a Material Safety or
                 Regulatory Issue........................................    82
          9.7.5  Post-Termination Rights to Wyeth Technology and Trubion
                 Technology..............................................    83
          9.7.6  Post-Termination Licenses to Wyeth Technology...........    84
          9.7.7  Post-Termination Transfer of Product Data and Filings
                 and Existing Trademarks.................................    84
          9.7.8  Manufacturing of Licensed Products After Termination....    85
          9.7.9  Post-Termination Disposition of Inventories of Licensed
                 Products................................................    86
          9.7.10 Continuation of Rights and Licenses Under Sections 6.1.1
                 and 6.1.2...............................................    86
          9.7.11 Continuation of Other Rights and Obligations............    86
    9.8   Modification of Agreement Terms by Wyeth.......................    86
    9.9   Survival of Certain Obligations................................    87
    9.10  Change of Control..............................................    88
          9.10.1 Definition..............................................    88
          9.10.2 Change of Control of Wyeth..............................    89
          9.10.3 Change of Control of Trubion............................    91

10. INDEMNIFICATION AND INSURANCE........................................    91
    10.1  Indemnification by Wyeth.......................................    91
    10.2  Indemnification by Trubion.....................................    91
    10.3  Procedure......................................................    92
    10.4  Insurance......................................................    93

11. DISPUTE RESOLUTION...................................................    93
    11.1  General........................................................    93
    11.2  Failure of Executive Officers to Resolve Dispute...............    93
    11.3  Disclaimer of Consequential and Punitive Damages...............    93

12. MISCELLANEOUS........................................................    93
    12.1  Periodic Executive Meetings....................................    93
    12.2  Assignment.....................................................    94
    12.3  Further Actions................................................    94
    12.4  Force Majeure..................................................    94
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    12.5  Non-Solicitation...............................................    94
    12.6  Correspondence and Notices.....................................    95
          12.6.1 Ordinary Notices........................................    95
          12.6.2 Extraordinary Notices...................................    95
    12.7  Amendment......................................................    96
    12.8  Waiver.........................................................    96
    12.9  Severability...................................................    96
    12.10 Descriptive Headings...........................................    96
    12.11 Governing Law..................................................    97
    12.12 Entire Agreement of the Parties................................    97
    12.13 Independent Contractors........................................    97
    12.14 Counterparts...................................................    97
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                                    EXHIBITS

Exhibit 1.122 - TRU-015
Exhibit 1.129 - Trubion Patent Rights
Exhibit 1.132 - Trubion Third Party Agreements
Exhibit 3.2.1 - Trubion's "Milestone One"
Exhibit 3.2.4 - Excluded Targets
Exhibit 4.4 - Adverse Event Reporting Procedures
Exhibit 5.2A - Stock Purchase Agreement
Exhibit 5.2B - Amendment to Investor Rights Agreement
Exhibit 5.3 - Additional Research and Development Expense Payments
Exhibit 8.2(d) - Third Party Rights
Exhibit 8.2(e) - Government Funding Agreements

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                                                                  EXECUTION COPY

                       COLLABORATION AND LICENSE AGREEMENT

     This Collaboration and License Agreement (the "Agreement") is entered into
as of December 19, 2005 (the "Signing Date"), by and between Wyeth, together
with its Affiliates (as defined below), acting through its Wyeth Pharmaceuticals
Division, a corporation organized and existing under the laws of the State of
Delaware and having a place of business at 500 Arcola Road, Collegeville,
Pennsylvania 19426 (collectively, "Wyeth") and Trubion Pharmaceuticals, Inc.,
together with its Affiliates (as defined below), a corporation organized and
existing under the laws of the State of Delaware and having a principal place of
business at 2401 4th Avenue, Suite 1050, Seattle, Washington 98121
(collectively, "Trubion"). Wyeth and Trubion may each be referred to herein
individually as a "Party" and collectively as the "Parties".

     WHEREAS, Wyeth is engaged in the research, development and
commercialization of pharmaceutical and health care products;

     WHEREAS, as of the Signing Date, Trubion has developed certain SMIPs (as
defined below) and CD20 Products (as defined below), as well as certain Patent
Rights (as defined below) and Know-How (as defined below) pertaining to
Trubion's SMIP technology platform;

     WHEREAS, Wyeth and Trubion desire to collaborate to discover, research and
develop, and Wyeth desires to research, develop, manufacture and commercialize,
Licensed Products (as defined below) as provided herein; and

     WHEREAS, Wyeth desires to obtain from Trubion, and Trubion desires to grant
to Wyeth, certain exclusive rights so that Wyeth may develop, manufacture and
commercialize such Licensed Products, as provided herein.

     NOW THEREFORE, in consideration of the mutual promises and covenants set
forth below and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the Parties hereby agree as
follows:

1.   DEFINITIONS.

     1.1. "ADDITIONAL RESEARCH AND DEVELOPMENT EXPENSE PAYMENT" shall have the
          meaning set forth in Section 5.3 hereof.

     1.2. "ADDITIONAL THIRD PARTY LICENSES" shall have the meaning set forth in
          Section 6.2.3(a) hereof.

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     1.3. "AFFILIATE(S)" shall mean, with respect to any Person, any other
          Person which controls, is controlled by or is under common control
          with such Person. A Person shall be regarded as in control of another
          entity if it owns or controls at least fifty percent (50%) of the
          equity securities of the subject entity entitled to vote in the
          election of directors (or, in the case of an entity that is not a
          corporation, for the election of the corresponding managing
          authority); provided, however, that the term "Affiliate" shall not
          include subsidiaries or other entities in which a Party or its
          Affiliates owns a majority of the ordinary voting power necessary to
          elect a majority of the board of directors or other governing board,
          but is restricted from electing such majority by contract or
          otherwise, until such time as such restrictions are no longer in
          effect.

     1.4. "AGREEMENT" shall have the meaning set forth in the preamble hereof.

     1.5. "BANKRUPTCY CODE" shall have the meaning set forth in Section 2.7
          hereof.

     1.6. "BLA" shall have the meaning set forth in Section 1.100 hereof.

     1.7. "CALENDAR QUARTER" shall mean the respective periods of three (3)
          consecutive calendar months ending on March 31, June 30, September 30
          or December 31, for so long as this Agreement is in effect.

     1.8. "CATEGORY 1 COVERED SMIP IMPROVEMENT" shall have the meaning set forth
          in Section 6.1.3(b) hereof.

     1.9. "CATEGORY 2 COVERED SMIP IMPROVEMENT" shall have the meaning set forth
          in Section 6.1.3(b) hereof.

     1.10. "CD20 ANTIGEN" shall mean the human protein antigen that is known as
          CD20, and identified as a full length CD20 protein antigen in ***, and
          any other protein that *** as the foregoing.

     1.11. "CD20 EFFECTIVE ROYALTY RATE" shall have the meaning set forth in
          Section 5.4.2(a) hereof.

     1.12. "CD20 PRODUCT" shall mean any TRU-015 Product and/or Follow-On CD20
          Product (as the context requires).

     1.13. "CELL LINES" shall mean the cell lines and any other expression
          systems that produce or express any SMIP.

     1.14. "CHANGE OF CONTROL" shall have the meaning set forth in Section
          9.10.1 hereof.

     1.15. "CLINICAL STUDY SUPPLIES" shall have the meaning set forth in Section
          4.9 hereof.

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     1.16. "COMBINATION PRODUCT" shall mean any product containing as active
          ingredients both (a) a Product and (b) one or more other
          pharmaceutically active compounds or substances.

     1.17. "COMBINATION SALE" shall have the meaning set forth in Section 1.76
          hereof.

     1.18. "COMMERCIALIZATION" OR "COMMERCIALIZE" shall mean activities directed
          to marketing, promoting, distributing, importing or selling a product.
          Commercialization shall not include any activities related to
          Manufacturing or Development.

     1.19. "COMMERCIALLY REASONABLE EFFORTS" shall mean, with respect to the
          efforts to be expended by any Party with respect to any objective,
          those reasonable, diligent, good faith efforts to accomplish such
          objective as such Party would normally use to accomplish a similar
          objective under similar circumstances. With respect to any objective
          relating to the Development and/or Commercialization of a Licensed
          Product by any Party, "Commercially Reasonable Efforts" shall mean
          those efforts and resources normally used by such Party with respect
          to a product owned or controlled by such Party, or to which such Party
          has similar rights, which product is of similar market potential and
          is at a similar stage in its development or life as is such Licensed
          Product, taking into account issues of safety, efficacy, product
          profile, the competitiveness of the marketplace, the proprietary
          position of the Licensed Product, the regulatory structure involved,
          profitability of the Licensed Product and other relevant commercial
          factors. A "COMMERCIALLY REASONABLE" action or decision of a Party
          refers in this Agreement to an action or decision taken or made by
          such Party using its Commercially Reasonable Efforts.

     1.20. "CONFIDENTIAL INFORMATION" of a Party shall mean all Know-How or
          other information, including, without limitation, proprietary
          information and materials (whether or not patentable) regarding such
          Party's technology, products, business information or objectives, that
          is communicated in any way or form by the Disclosing Party to the
          Receiving Party, either prior to or after the Effective Date of this
          Agreement, and whether or not such Know-How or other information is
          identified as confidential at the time of disclosure; provided that,
          information not identified as confidential by the Disclosing Party
          shall be deemed to be Confidential Information of the Disclosing Party
          if the Receiving Party knows, or should have had a reasonable
          expectation, that the information communicated by the Disclosing Party
          is Confidential Information of the Disclosing Party. The terms and
          conditions of this Agreement shall be considered Confidential
          Information of both Parties.

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     1.21. "CONJUGATE(S)" shall mean SMIP(s) fused genetically or linked, either
          directly or through a linker molecule, with any biological,
          cytostatic, cytotoxic or radioactive agent.

     1.22. "CONTROL" OR "CONTROLLED" shall mean with respect to any (a) item of
          information, including, without limitation, Know-How, or (b)
          intellectual property right, the possession (whether by ownership or
          license, other than pursuant to this Agreement) by a Party of the
          ability to grant to the other Party a license or to extend other
          rights as provided herein, under such item or right without violating
          the terms of any agreement or other arrangements with any Third Party.

     1.23. "CO-PROMOTION" shall mean the joint promotion of a CD20 Product in
          the United States by both Parties and/or their respective Affiliates
          under the same CD20 Product Trademark(s). "CO-PROMOTE," when used as a
          verb, shall mean to engage in such Co-Promotion.

     1.24. "CO-PROMOTION PERIOD" shall have the meaning set forth in Section
          4.11 hereof.

     1.25. "COVERED SMIP IMPROVEMENT" shall have the meaning set forth in
          Section 6.1.2 hereof.

     1.26. "DEPOSITED PROTEIN" shall have the meaning set forth in Section 1.45
          hereof.

     1.27. "DESIGNATED TARGET(S)" shall have the meaning set forth in Section
          9.8 hereof.

     1.28. "DEVELOPMENT" OR "DEVELOP" shall mean non-clinical and clinical drug
          development activities pertaining to a product, including, without
          limitation, toxicology, pharmacology, test method development and
          stability testing, process development, formulation development,
          delivery system development, quality assurance and quality control
          development, statistical analysis, clinical studies (including pre-
          and post-approval studies), regulatory affairs, pharmacovigilance and
          Regulatory Approval and clinical study regulatory activities
          (including regulatory activities directed to obtaining pricing and
          reimbursement approvals).

     1.29. "DEVELOPMENT PLAN" shall mean the written plan for the Development of
          CD20 Products described in Section 4.8 hereof.

     1.30. "DISCLOSING PARTY" shall have the meaning set forth in Section 7.1
          hereof.

     1.31. "EFFECTIVE DATE" shall mean the later to occur of (a) the Signing
          Date and (b) the HSR Clearance Date.

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     1.32. "EXCHANGE ACT" shall mean the Securities Exchange Act of 1934, as
          amended.

     1.33. "EXCLUDED TARGET(S)" shall mean the Target(s) described in Section
          3.2.4 hereof as Excluded Target(s).

     1.34. "EXCLUSIVITY COVENANTS" shall have the meaning set forth in Section
          9.10.2(c) hereof.

     1.35. "EXECUTIVE OFFICERS" shall mean the President of Wyeth
          Pharmaceuticals (or an executive officer of Wyeth designated by such
          President of Wyeth Pharmaceuticals) and the Chief Executive Officer of
          Trubion (or an executive officer of Trubion designated by such Chief
          Executive Officer).

     1.36. "EXERCISE NOTICE" shall have the meaning set forth in Section
          9.10.2(c) hereof.

     1.37. "EXISTING ACTIVITIES" shall have the meaning set forth in Section
          9.10.2(c) hereof.

     1.38. "EXISTING TRADEMARKS" shall have the meaning set forth in Section
          9.7.1(a).

     1.39. "FDA" shall mean the United States Food and Drug Administration or
          any successor agency thereto.

     1.40. "FD&C ACT" shall mean the United States Federal Food, Drug, and
          Cosmetic Act (21 U.S.C. Section 301 et seq.), as amended, and the
          rules and regulations promulgated thereunder.

     1.41. "FIRST COMMERCIAL SALE" shall mean, with respect to a given Licensed
          Product and any country in the Territory, the first sale or transfer
          for value of such Licensed Product under this Agreement by Wyeth or
          its sublicensees to a Third Party in such country following receipt of
          marketing authorization from the appropriate Regulatory Authority
          permitting commercial sale of such Licensed Product in such country.

     1.42. "FOLLOW-ON CD20 PRODUCT" shall mean any product containing a
          Follow-On CD20 SMIP.

     1.43. "FOLLOW-ON CD20 SMIP" shall mean any SMIP (other than TRU-015)
          directed against the CD20 Antigen or a portion thereof.

     1.44. "FTE" shall mean a full time equivalent scientific person (M.S. or
          Ph.D. level) year, consisting of a minimum of a total of one thousand
          eight hundred eighty (1,880) hours per year of scientific work by an
          employee of Trubion on or directly related to and in support of the
          Research Program. Work on or directly related to the Research Program
          can include, but is not

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          limited to, experimental preclinical laboratory and research work,
          recording and writing up results, reviewing literature and references,
          holding scientific discussions, managing and leading scientific staff
          and carrying out management duties, in each case where such activities
          are directly related to the Research Program.

     1.45. "HAS THE SAME SEQUENCE" shall mean, with respect to a specific
          protein (as described by an amino acid sequence identified by a
          GenBank accession number; a "New Protein"), that another specific
          protein (as described by an amino acid sequence identified by a
          GenBank accession number; each, a "Deposited Protein") has at least
          *** amino acid sequence identity over at least *** of the length of
          the New Protein.

          By way of example only, if the New Protein consists of *** amino
          acids, and any contiguous sequence of *** amino acids contained in the
          Deposited Protein has at least *** sequence identity to any contiguous
          sequence of *** amino acids in the New Protein (that is, at least ***
          of the *** contiguous amino acids in such Deposited Protein sequence
          are identical to any *** of any *** contiguous amino acids in such New
          Protein), then the New Protein Has The Same Sequence as the Deposited
          Protein.

     1.46. ***

     1.47. ***

     1.48. ***

     1.49. ***

     1.50. "HSR ACT" shall mean the Hart-Scott-Rodino Antitrust Improvements Act
          of 1976, as amended, and the rules and regulations promulgated
          thereunder.

     1.51. "HSR FILING" shall mean filings by Wyeth and Trubion with the United
          States Federal Trade Commission and the Antitrust Division of the
          United States Department of Justice of a Notification and Report Form
          for Certain Mergers and Acquisitions (as that term is defined in the
          HSR Act) with respect to the matters set forth in this Agreement,
          together with all required documentary attachments thereto.

     1.52. "HSR CLEARANCE DATE" shall mean the earliest date on which the
          Parties have actual knowledge that all applicable waiting periods
          under the HSR Act with respect to the transactions contemplated
          hereunder have expired or have been terminated.

     1.53. "IND" shall mean an Investigational New Drug Application, as defined
          in the FD&C Act, that is required to be filed with the FDA before
          beginning clinical testing of a Licensed Product in human subjects, or
          an equivalent foreign filing.

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     1.54. "INDEMNIFIED PARTY" shall have the meaning set forth in Section 10.3
          hereof.

     1.55. "INDEMNIFYING PARTY" shall have the meaning set forth in Section 10.3
          hereof.

     1.56. "INITIAL TERM" shall have the meaning set forth in Section 3.3.1
          hereof.

     1.57. "JDC" shall have the meaning set forth in Section 4.7 hereof.

     1.58. "JOINT INVENTION(S)" shall have the meaning set forth in Section
          6.1.1 hereof.

     1.59. "JOINT KNOW-HOW" shall mean that Know-How related to the Licensed
          Products that is jointly owned by the Parties in accordance with
          Section 6.1.1 of this Agreement.

     1.60. "JOINT PATENT COMMITTEE" shall mean the committee described in
          Section 6.1.3 hereof.

     1.61. "JOINT PATENT RIGHT(S)" shall mean those Patent Right(s) that claim
          Joint Know-How or Joint Invention(s).

     1.62. "JOINT TECHNOLOGY" shall mean the Joint Patent Rights, the Joint
          Inventions and the Joint Know-How.

     1.63. "JPT" shall have the meaning set forth in Section 4.8 hereof.

     1.64. "JRC" shall have the meaning set forth in Section 3.4.1 hereof.

     1.65. "JRC LIAISON" shall mean a JRC member designated by a Party as its
          "JRC Liaison" in accordance with Section 3.4.3 hereof.

     1.66. "KNOW-HOW" shall mean inventions, discoveries, data, information,
          processes, methods, techniques, materials, technology, results or
          other know-how, whether or not patentable.

     1.67. "LIABILITIES" shall have the meaning set forth in Section 10.1
          hereof.

     1.68. "LICENSED PRODUCT(S)" shall mean any Product(s) or Combination
          Product(s).

     1.69. "LICENSED TARGET(S)" shall mean any Trubion Target(s) or Wyeth
          Target(s), so long as they remain the subject of the licenses granted
          to Wyeth under this Agreement.

     1.70. "MAJOR INDICATION(S)" shall mean, with respect to any CD20 Product,
          any indication with a prevalence-based patient population of at least
          two hundred thousand (200,000) patients in the United States,
          including,

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          without limitation, non-Hodgkin's lymphoma, rheumatoid arthritis,
          systemic lupus erythematosus, Crohn's disease and multiple sclerosis.

     1.71. "MAJOR MARKET COUNTRY" shall mean any of the United States, the
          United Kingdom, France, Germany, Italy, Spain or Japan.

     1.72. "MANUFACTURING" or "MANUFACTURE" shall mean activities directed to
          producing, manufacturing, processing, filling, finishing, packaging,
          labeling, quality assurance testing and release, shipping and storage
          of a product.

     1.73. "NCBI" shall have the meaning set forth in Section 3.2.1 hereof.

     1.74. "NDA" shall have the meaning set forth in Section 1.100 hereof.

     1.75. "NET COMBINATION SALE AMOUNT" shall have the meaning set forth in
          Section 1.76 hereof.

     1.76. "NET SALES" shall mean the gross amounts charged for sales of
          Licensed Products (on which payments are due under this Agreement) by
          Wyeth or its sublicensees to Third Parties, less the sum of (a) and
          (b) where (a) is a provision, determined under Generally Accepted
          Accounting Principles in the United States and in accordance with
          Wyeth's customary and usual accrual procedures, consistently applied,
          for the accrual of (i) trade, cash, quantity and wholesaler discounts
          or rebates (other than price discounts granted at the time of sale),
          if any, allowed or paid, (ii) credits or allowances given or made for
          rejection or return of, previously sold Licensed Products or for
          retroactive price reductions (including Medicaid, managed care and
          similar types of rebates), (iii) taxes, duties or other governmental
          charges levied on or measured by the billing amount (excluding income
          and franchise taxes), as adjusted for rebates and refunds, and (iv)
          charges for packing, freight, and shipping to the extent included in
          the invoice price and (b) is a periodic adjustment (positive or
          negative, as applicable), determined under Generally Accepted
          Accounting Principles in the United States and in accordance with
          Wyeth's customary and usual adjustment procedures, consistently
          applied, of the provision determined in (a) to reflect amounts
          actually incurred for (i), (ii), (iii) and (iv) based on amounts
          actually invoiced or as separately set forth in agreements with Third
          Parties or as deducted or paid as required by applicable law or
          regulations. (The deductions described in (i), (ii), (iii) and (iv)
          are referred to herein as "Permitted Deductions.") In the case of any
          sale of Licensed Products for consideration other than cash, Net Sales
          shall be calculated on the fair market value of the consideration
          received.

          Notwithstanding the foregoing, if a Licensed Product is sold as a
          Combination Product (a "Combination Sale"), the Net Sales for such

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          Combination Product shall be the portion of such Combination Sale
          allocable to the Licensed Product determined as follows:

          Except as provided below, the Net Sales amount for a Combination Sale
          shall equal the gross amount invoiced for the Combination Sale,
          reduced by the Permitted Deductions (the "Net Combination Sale
          Amount"), multiplied by the fraction A/(A+B), where:

               A is the invoice price, in the country where such Combination
               Sale occurs, of the Licensed Product contained in the Combination
               Product, if sold as a separate product in such country by Wyeth
               or its sublicensees, as the case may be, and B is the aggregate
               of the invoice price or prices, in such country, of products
               which collectively contain as their respective sole active
               ingredient such other pharmaceutically active compounds or
               substances, as the case may be, included in the Combination
               Product, if sold separately in such country by Wyeth or its
               sublicensees, as applicable.

          In the event that Wyeth or its sublicensees sell the Licensed Product
          included in a Combination Product as a separate product in a country,
          but do not separately sell all of the other pharmaceutically active
          compounds or substances, as the case may be, included in such
          Combination Product in such country, the calculation of the Net Sales
          amount for such Combination Sale shall be determined by multiplying
          the Net Combination Sale Amount by the fraction A/C where:

               A is the average wholesale price, in such country, charged by
               Wyeth or its sublicensees, as the case may be, for the Licensed
               Product contained in such Combination Product, when sold as a
               separate product by Wyeth or its sublicensees, as applicable, and
               C is the average wholesale price, in such country, charged by
               Wyeth or its sublicensees, as applicable, for the entire
               Combination Product.

          In the event that Wyeth or its sublicensees do not sell the Licensed
          Product included in a Combination Product as a separate product in a
          country where such Combination Sale occurs, but do separately sell
          products which collectively contain as their respective sole active
          ingredient all of the other pharmaceutically active compounds or
          substances, as the case may be, included in the Combination Product in
          such country, the calculation of Net Sales resulting from such
          Combination Sale shall be determined by multiplying the Net
          Combination Sale Amount by the fraction (C-D)/C, where:

               C is the average wholesale price, in such country, charged by
               Wyeth or its sublicensees, as the case may be, for the entire

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               Combination Product, and D is the average wholesale price charged
               by Wyeth or its sublicensees, as the case may be, for the
               products which collectively contain as their sole active
               ingredient such other pharmaceutically active compounds or
               substances, as the case may be, included in the Combination
               Product.

          Where active ingredient portions of a Combination Product are sold
          separately as other products but in different dosage strengths than
          are in the Combination Product, the calculation of the Net Sales
          amount for such Combination Product shall be based on appropriate
          proration of the amounts of each active ingredient component included
          therein when applying the formulas set forth above.

          Where the calculation of Net Sales resulting from a Combination Sale
          in a country cannot be determined by any of the foregoing methods, the
          calculation of Net Sales for such Combination Sale shall be that
          portion of the Net Combination Sale Amount reasonably determined in
          good faith by the Parties as properly reflecting the value of the
          Licensed Product included in the Combination Product.

          Notwithstanding the foregoing, Net Sales shall not include any
          reimbursement received by Wyeth or its sublicensees in respect of the
          use of a Licensed Product in a country solely as part of a clinical
          trial prior to the receipt of marketing authorization required to
          commence commercial sales of such Licensed Product in such country.

     1.77. "NEW PROTEIN" shall have the meaning set forth in Section 1.45
          hereof.

     1.78. "NICHE INDICATION(S)" shall mean, with respect to any CD20 Product,
          any indication, including, but not limited to, ***, for such CD20
          Product other than a Major Indication.

     1.79. "NOTICE OF BREACH" shall have the meaning set forth in Section 9.5
          hereof.

     1.80. "NOTICE OF MODIFICATION" shall have the meaning set forth in Section
          9.5 hereof.

     1.81. "NOTICE OF TERMINATION" shall have the meaning set forth in Section
          9.5 hereof.

     1.82. "OTHER PRODUCT" shall mean any product containing a SMIP directed
          against a Wyeth Target or a portion thereof.

     1.83. "PART(Y/IES)" shall have the meaning set forth in the preamble
          hereof.

     1.84. "PATENT RIGHTS" shall mean any and all (a) patents, (b) pending
          patent applications, including, without limitation, all provisional
          applications, substitutions, continuations, continuations-in-part,
          divisions, renewals, and

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          all patents granted thereon, (c) all patents-of-addition, reissues,
          reexaminations and extensions or restorations by existing or future
          extension or restoration mechanisms, including, without limitation,
          supplementary protection certificates or the equivalent thereof, (d)
          inventor's certificates, and (e) all United States and foreign
          counterparts of any of the foregoing.

     1.85. "PERSON" shall mean an individual, sole proprietorship, partnership,
          limited partnership, limited liability partnership, corporation,
          limited liability company, business trust, joint stock company, trust,
          incorporated association, joint venture or similar entity or
          organization, including a government or political subdivision,
          department or agency of a government.

     1.86. "PERMITTED DEDUCTION" shall have the meaning set forth in Section
          1.76 hereof.

     1.87. "PHASE I CLINICAL STUDY" shall mean a study of a Licensed Product in
          human subjects with the endpoint of determining initial tolerance,
          safety or pharmacokinetic information in single dose, single ascending
          dose, multiple dose and/or multiple ascending dose regimens.

     1.88. "PHASE II CLINICAL STUDY" shall mean a study of a Licensed Product in
          human patients to determine initial efficacy and dose range finding
          before embarking on Phase III Clinical Studies.

     1.89. "PHASE IIA CLINICAL STUDY" shall mean Trubion's TRU-015 Protocol
          15001.

     1.90. "PHASE IIB CLINICAL STUDY" shall mean Trubion's TRU-015 Protocol
          15002.

     1.91. "PHASE III CLINICAL STUDY" shall mean a pivotal study (whether or not
          denominated a "Phase III" clinical study under applicable regulations)
          in human patients with a defined dose or a set of defined doses of a
          Licensed Product designed to ascertain efficacy and safety of such
          Licensed Product for the purpose of enabling the preparation and
          submission of Regulatory Approval Applications to the competent
          Regulatory Authorities in a country of the Territory.

     1.92. "PREVIOUSLY DEPOSITED PROTEIN" shall have the meaning set forth in
          Section 3.2.4(b) hereof.

     1.93. "PRODUCT" shall mean any CD20 Product, ***, or Other Product, or any
          Conjugate of any CD20 Product, ***, or Other Product.

     1.94. "PRODUCT DATA AND FILINGS" shall mean (a) all clinical protocols,
          studies, clinical data and results used in or resulting from any
          clinical trial of any

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          Licensed Product and (b) all INDs, Regulatory Approval Applications
          and Regulatory Approvals regarding any Licensed Product.

     1.95. "PRODUCT LICENSE" shall have the meaning set forth in Section 2.1.1
          hereof.

     1.96. "PRODUCT-RELATED PATENT RIGHTS" shall have the meaning set forth in
          Section 6.2.1(a) hereof.

     1.97. "PROVISIONAL EXCLUDED TARGET" shall mean a Target described in
          Section 3.2.4 hereof as a Provisional Excluded Target.

     1.98. "RECEIVING PARTY" shall have the meaning set forth in Section 7.1
          hereof.

     1.99. "RECOMBINANT DNA" shall mean the DNA sequences encoding any SMIP
          including, without limitation, any DNA plasmid expression construct
          encoding any such SMIP.

     1.100. "REGULATORY APPROVAL" shall mean the technical, medical and
          scientific licenses, registrations, authorizations and approvals
          (including, without limitation, approvals of New Drug Applications
          ("NDAs") or Biologic License Applications ("BLAs"), supplements and
          amendments, pre- and post- approvals, pricing approvals, and labeling
          approvals) of any national, supra-national, regional, state or local
          regulatory agency, department, bureau, commission, council or other
          governmental entity, necessary for the commercial Manufacture,
          distribution, marketing, promotion, offer for sale, use, import,
          export and sale of Licensed Product(s) in a regulatory jurisdiction in
          the Territory. For the sake of clarity, Regulatory Approval shall not
          be deemed to have been obtained in a country other than the United
          States until any applicable governmental pricing approvals have also
          been obtained in such country. Regulatory Approval of a Licensed
          Product shall be deemed to have been obtained in the United States
          immediately upon BLA approval for such Licensed Product in the United
          States.

     1.101. "REGULATORY APPROVAL APPLICATION" shall mean an application
          submitted to the appropriate Regulatory Authority seeking Regulatory
          Approval of a Licensed Product for use in one or more therapeutic
          indications in a regulatory jurisdiction within the Territory.

     1.102. "REGULATORY AUTHORIT(Y/IES)" shall mean any national (e.g., the
          FDA), supra-national (e.g., the European Commission, the Council of
          the European Union, or the European Agency for the Evaluation of
          Medicinal Products), regional, state or local regulatory agency,
          department, bureau, commission, council or other governmental entity
          in each country of the Territory involved in the granting of
          Regulatory Approval for a Licensed Product.

     1.103. "RELEASED TARGET" shall have the meaning set forth in Section 3.2.2
          hereof.

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     1.104. "REPLACEMENT TARGET" shall have the meaning set forth in Section
          3.2.3 hereof.

     1.105. "RESEARCH BUDGET" shall have the meaning set forth in Section 3.5
          hereof.

     1.106. "RESEARCH PLAN" shall mean the written plan for the conduct of the
          Research Program described in Section 3.5 hereof as approved and
          amended by the Parties in accordance with Section 3.5 hereof.

     1.107. "RESEARCH PROGRAM" shall have the meaning set forth in Section 3.1
          hereof.

     1.108. "RESEARCH PROGRAM DATA" shall have the meaning set forth in Section
          3.7 hereof.

     1.109. "RESEARCH TERM" shall have the meaning set forth in Section 3.3.1
          hereof.

     1.110. "ROYALTY PERIOD" shall mean the period of time beginning on the date
          of the First Commercial Sale of a Licensed Product in any country and,
          on a Licensed Product-by-Licensed Product and country-by-country
          basis, extending until the earlier of (a) the termination of this
          Agreement pursuant to Article 9 hereof with respect to such Licensed
          Product in such country or (b) the later of (i) the date on which the
          last Valid Claim included within the Trubion Technology ceases to be a
          Valid Claim, which Valid Claim would be infringed by the composition,
          Manufacture, use, sale, offer for sale or importing of such Licensed
          Product in such country, or (ii)(A) with respect to CD20 Products, the
          ten (10) year anniversary of the First Commercial Sale for the first
          Major Indication of such CD20 Product in such country (provided,
          however, that if such CD20 Product has received Regulatory Approval
          for a Niche Indication in such country but has not received Regulatory
          Approval for a Major Indication in such country, the Royalty Period as
          defined under and for purposes of this clause (ii)(A) for such CD20
          Product in such country shall be suspended beginning on the ten (10)
          year anniversary of the First Commercial Sale of such CD20 Product in
          such country until such time, if at all, as Regulatory Approval has
          been obtained permitting the marketing of such CD20 Product for a
          Major Indication in such country, at which point such Royalty Period
          shall commence with respect to such CD20 Product for a Major
          Indication) and (B) with respect to each other Licensed Product, the
          ten (10) year anniversary of the First Commercial Sale of such
          Licensed Product in such country.

     1.111. "SIGNING DATE" shall have the meaning set forth in the preamble
          hereof.

     1.112. "SMIP(S)" or small modular immuno-pharmaceutical(s) shall mean a
          single chain polypeptide that (i) *** (ii) binds with specificity to a
          target antigen, (iii) has a binding domain, and (iv) may have an
          effector domain which may or may not have effector function, ***.

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     1.113. "SMIP IMPROVEMENT" shall mean an invention consisting of any
          modification to the polynucleotide sequence encoding or the amino acid
          sequence of a SMIP, if the practice of such invention would infringe
          Patent Rights Controlled by Trubion at the time such invention is
          made.

     1.114. "SPECIFICALLY BINDS" shall mean, in the case of a SMIP or other
          protein, the binding of such SMIP or other protein to a Target (or a
          portion thereof) above the level of background binding and wherein
          such SMIP or other protein is designed or being developed to exert its
          biological effect through binding to such Target (or such portion
          thereof).

     1.115. "SUCCESSOR PARTY" shall have the meaning set forth in Section
          9.10.2(a) hereof.

     1.116. "SUED PARTY" shall have the meaning set forth in Section 6.2.3(b)
          hereof.

     1.117. "TARGET" shall mean a specific named human protein that is
          identified as a full length protein of that name and further
          identified by up to *** GenBank accession numbers for its amino acid
          sequence, as well as any additional protein(s) that Has The Same
          Sequence as such specific named human protein.

     1.118. "TARGET CANDIDATE" shall have the meaning set forth in Section 3.2.1
          hereof.

     1.119. "TERRITORY" shall mean the entire world.

     1.120. "THIRD PART(Y/IES)" shall mean any Person(s) other than Wyeth or
          Trubion.

     1.121. "TRADEMARK" shall mean those trademarks used in connection with the
          Commercialization of any Licensed Product by Wyeth or its sublicensees
          hereunder.

     1.122. "TRU-015" shall mean the chimeric SMIP directed against the CD20
          Antigen that is currently designated by Trubion as "TRU-015," as
          further described on Exhibit 1.122 attached hereto.

     1.123. "TRU-015 PRODUCT" shall mean any product containing TRU-015.

     1.124. "TRUBION" shall have the meaning set forth in the preamble hereof.

     1.125. "TRUBION ADDITIONAL THIRD PARTY LICENSE" shall have the meaning set
          forth in Section 6.2.3(a) hereof.

     1.126. "TRUBION INDEMNIFIED PARTY" shall have the meaning set forth in
          Section 10.1 hereof.

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     1.127. "TRUBION KNOW-HOW" shall mean any Know-How, other than the Joint
          Know-How, that (a) Trubion Controls as of the Effective Date or that
          comes into the Control of Trubion during the term of this Agreement
          (other than through the grant of a license by Wyeth) and (b) relates
          to any Cell Lines, Conjugates, Licensed Products, Recombinant DNA,
          SMIPs, Licensed Targets, Target Candidates or the Development,
          Manufacture or use of any of the foregoing.

     1.128. "TRUBION LAWYERS" shall have the meaning set forth in Section 3.2.1
          hereof.

     1.129. "TRUBION PATENT RIGHTS" shall mean Patent Rights, other than Joint
          Patent Rights, that (a) Trubion Controls as of the Effective Date or
          that come into the Control of Trubion during the term of this
          Agreement and (b) claim any Trubion Know-How. Those Trubion Patent
          Rights known to be existing as of the Signing Date are listed on
          Exhibit 1.129 attached hereto.

     1.130. "TRUBION TARGET" shall mean each of the human CD20 Antigen and/or
          ***, as the context may require.

     1.131. "TRUBION TECHNOLOGY" shall mean Trubion's interest in the Trubion
          Patent Rights, the Trubion Know-How, the Joint Technology and the
          Research Program Data.

     1.132. "TRUBION THIRD PARTY AGREEMENT(S)" shall mean the agreements
          specified on Exhibit 1.132 between Trubion and the indicated Third
          Parties that relate to the research, Development, Manufacture and/or
          Commercialization of Licensed Products under this Agreement.

     1.133. "U.S. WYETH PHARMACEUTICALS" shall have the meaning set forth in
          Section 12.5 hereof.

     1.134. "VALID CLAIM" shall mean a claim that (a) in the case of any
          unexpired United States or foreign patent, shall not have been
          dedicated to the public, disclaimed, nor held invalid or unenforceable
          by a court or government agency of competent jurisdiction in an
          unappealed or unappealable decision, or (b) in the case of any United
          States or foreign patent application, (i) shall not have been
          cancelled, withdrawn or abandoned, without being refiled in another
          application in the applicable jurisdiction, (ii) shall not have been
          finally rejected by an administrative agency or other governmental
          action from which no appeal can be taken and (iii) shall not have been
          pending for more than ***, in either case which claim (if issued)
          would cover the Manufacture, use or sale of any Licensed Product. For
          purposes of this definition, the time period for which a claim is
          pending shall begin on the priority date for such claim, and shall
          continue until such claim is either issued or is no longer deemed to
          be a Valid Claim in accordance with the preceding sentence regardless
          of whether such claim is

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          amended or refiled in another application in the applicable
          jurisdiction. If a claim of a patent application which ceased to be a
          Valid Claim under (b) due to the passage of time later issues as part
          of a patent described within (a) then it shall again be considered to
          be a Valid Claim effective as of the issuance of such patent.

     1.135. "WYETH" shall have the meaning set forth in the preamble hereof.

     1.136. "WYETH APPLIED TECHNOLOGY" shall mean, with respect to any Licensed
          Product, that Wyeth Technology which (a) Wyeth had applied to such
          Licensed Product prior to any termination of any rights under this
          Agreement with respect to such Licensed Product, provided that such
          Wyeth Technology is necessary or useful for the continued research,
          Development, Manufacture or Commercialization of such Licensed Product
          as it exists at the time of such termination, or (b) Wyeth had
          incorporated into such Licensed Product prior to any termination of
          rights under this Agreement with respect to such Licensed Product;
          provided that Wyeth shall use its Commercially Reasonable Efforts to
          sublicense or otherwise transfer rights under any Third-Party license
          to which the use or exploitation of such Wyeth Applied Technology is
          subject; and further provided, however, that with respect to each of
          clauses (a) and (b) of this Section 1.136, such Wyeth Technology shall
          not include any of Wyeth's conjugation technology.

     1.137. "WYETH INDEMNIFIED PARTY" shall have the meaning set forth in
          Section 10.2 hereof.

     1.138. "WYETH KNOW-HOW" shall mean any Know-How, other than the Joint
          Know-How, that (a) Wyeth Controls as of the Effective Date or that
          comes into the Control of Wyeth (other than as a result of the
          licenses granted by Trubion to Wyeth under Section 2.1 hereof) during
          the term of this Agreement and (b) relates to the Cell Lines,
          Conjugates, Recombinant DNA, Licensed Products, SMIPs, Target
          Candidates or Licensed Targets or the Development, Manufacture, use or
          Commercialization of any of the foregoing.

     1.139. "WYETH PATENT RIGHTS" shall mean Patent Rights, other than the Joint
          Patent Rights, that (a) Wyeth Controls as of the Effective Date or
          that come into the Control of Wyeth (other than as a result of the
          licenses granted by Trubion to Wyeth under Section 2.1 hereof) during
          the term of this Agreement and (b) claim any Wyeth Know-How.

     1.140. "WYETH TARGETS" shall mean the Targets designated by Wyeth under the
          Research Program, as described in Section 3.2 hereof.

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     1.141. "WYETH TECHNOLOGY" shall mean Wyeth's interest in the Wyeth Patent
          Rights, the Wyeth Know-How, the Joint Technology and the Research
          Program Data.

2.   LICENSES.

     2.1. LICENSES TO WYETH.

          2.1.1. EXCLUSIVE LICENSES. Subject to the terms and conditions of this
               Agreement, Trubion, effective as of the Effective Date, hereby
               grants to Wyeth an exclusive license (exclusive even as to
               Trubion, except to the extent necessary for Trubion to perform
               its obligations under this Agreement), with the right to grant
               sublicenses in accordance with the provisions of Section 2.4
               hereof, under the Trubion Technology, to research, Develop, have
               Developed, make, have made, Manufacture, use, have used, import,
               have imported, export, have exported, distribute, have
               distributed, market, have marketed, offer and have offered for
               sale, sell, have sold and Commercialize (subject to Section 4.11)
               Licensed Products in the Territory (the license granted under
               this Section 2.1.1 is sometimes referred to herein as the
               "Product License").

          2.1.2. RETAINED RIGHTS OF TRUBION. For the avoidance of doubt, but
               subject to Sections 2.3 and 3.2 hereof, Trubion shall retain: (a)
               all rights under the Trubion Technology with respect to the
               research, Development, Manufacture, use and Commercialization of
               SMIPs that (i) *** to Targets that are not Licensed Targets and
               (ii) do not *** to any Licensed Targets; and (b) the right to use
               SMIPs which *** to one or more Licensed Targets in in vitro
               studies conducted solely as part of Trubion's internal research
               efforts, provided, however, that Trubion shall not provide any
               such SMIP (that *** to a Licensed Target) to any Third Party or
               utilize any such SMIP (that *** to a Licensed Target) in a
               collaboration with any Third Party, except with Wyeth's prior
               written consent.

     2.2. LICENSE TO TRUBION. Wyeth hereby grants to Trubion a royalty-free
          non-exclusive license, with no right to grant sublicenses, under the
          Wyeth Technology, solely for the purpose of, and limited to, Trubion's
          use of the Wyeth Technology in connection with the Trubion Technology
          to research, Develop, have Developed, make, have made, use and have
          used Licensed Products to fulfill its obligations under this
          Agreement. In addition, Wyeth hereby grants to Trubion the
          non-exclusive license under Wyeth's rights to Covered SMIP
          Improvements as set forth in greater detail in Section 6.1.2.

     2.3. EXCLUSIVITY.

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          2.3.1. CD20 PRODUCT EXCLUSIVITY. Subject to Section 2.3.3, and except
               for Development of the CD20 Products pursuant to the terms of
               this Agreement, neither Party shall Develop any human therapeutic
               product that contains a protein that *** to the CD20 Antigen
               during the time period beginning on the Effective Date and ending
               on the earlier of: (a) the First Commercial Sale of any CD20
               Product for a Major Indication in a Major Market Country or (b)
               the termination of the licenses granted by Trubion to Wyeth under
               this Agreement with respect to all CD20 Products.

               Subject to Section 2.3.3, and except for Commercialization of the
               CD20 Products pursuant to the terms of this Agreement, neither
               Party shall Commercialize any human therapeutic product that
               contains a protein that *** to the CD20 Antigen during the time
               period beginning on the Effective Date and ending on the earlier
               of: (a) five (5) years after the First Commercial Sale of any
               CD20 Product for a Major Indication in a Major Market Country or
               (b) the termination of the licenses granted by Trubion to Wyeth
               under this Agreement with respect to all CD20 Products.

          2.3.2. *** EXCLUSIVITY. Subject to Section 2.3.3, and except for
               Development of the *** pursuant to the terms of this Agreement,
               neither Party shall Develop any human therapeutic product that
               contains a protein that *** to the *** during the time period
               beginning on the Effective Date and ending on the earlier of: (a)
               the First Commercial Sale of any *** in any Major Market Country
               or (b) the termination of the licenses granted by Trubion to
               Wyeth under this Agreement with respect to all ***.

               Subject to Section 2.3.3, and except for Commercialization of the
               *** pursuant to the terms of this Agreement, neither Party shall
               Commercialize any human therapeutic product that contains a
               protein that *** to the *** during the time period beginning on
               the Effective Date and ending on the earlier of: (a) five (5)
               years after the First Commercial Sale of any *** in any Major
               Market Country or (b) the termination of the licenses granted by
               Trubion to Wyeth under this Agreement with respect to all ***.

          2.3.3. LIMITATIONS. The exclusivity provisions of Sections 2.3.1 and
               2.3.2 above (a) shall not apply to Wyeth's Manufacture of any
               product for a Third Party pursuant only to a contract
               manufacturing or supply agreement between Wyeth and such Third
               Party where Wyeth is acting only as a contract manufacturer or
               supplier for such Third Party, (b) shall in no

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               way limit any of the licenses granted by Trubion to Wyeth under
               Section 2.1 hereof, and (c) shall in no way limit any of the
               retained rights of Trubion set forth in Section 2.1.2 hereof.

     2.4. SUBLICENSING. Wyeth may grant to one or more Third Parties sublicenses
          of the rights granted to it under Section 2.1 hereof at any time;
          provided that Wyeth shall execute a written agreement with each such
          sublicensee and shall comply with the following: Each such sublicense
          (a) shall be subject and subordinate to, and consistent with, the
          terms and conditions of this Agreement, (b) shall not in any way
          diminish, reduce or eliminate any of Wyeth's obligations under this
          Agreement, (c) shall require each such sublicensee to comply with all
          applicable terms of this Agreement, including to keep books and
          records, and permit Wyeth to audit (either directly or through an
          independent auditor) such books and records, and (d) shall provide
          that any such sublicensee shall not further sublicense except on terms
          consistent with this Section 2.4. Wyeth shall provide Trubion with a
          copy of each such sublicense agreement within thirty (30) days after
          the execution thereof. Such copy may be redacted to exclude
          confidential, non-Licensed Product-related information and financial
          information (other than such financial information that is necessary
          for assessing the obligations to Trubion under this Agreement). Upon
          Trubion's request and at Trubion's expense, Wyeth shall exercise its
          right to conduct an audit of a sublicensee's books and records
          pertaining to the sale of a Licensed Product under any such sublicense
          agreement at the next time that conducting such an audit is
          permissible under such sublicense agreement. Wyeth shall provide
          Trubion with a copy of the report of the findings made in any such
          audit. If such audit reveals that such sublicensee has understated its
          Net Sales by *** or more, Wyeth shall be responsible for the costs of
          the audit. Wyeth shall remain responsible for its obligations
          hereunder and for the performance of its sublicensees (including,
          without limitation, making all payments due Trubion by reason of any
          Net Sales of Licensed Products), and shall ensure that any such
          sublicensees comply with all relevant provisions of this Agreement. In
          the event of any uncured material breach by any sublicensee under a
          sublicense agreement that would constitute a breach of Wyeth's
          obligations under this Agreement, Wyeth will promptly inform Trubion
          in writing and shall take such action which in Wyeth's reasonable
          business judgment will address such default; provided, however, any
          such uncured material breach by such sublicensee of an obligation that
          would constitute a breach of Wyeth's obligations under this Agreement
          shall be deemed an uncured material breach of Wyeth hereunder unless
          Wyeth cures such material breach within the time provided under
          Section 9.5 hereof.

     2.5. DIRECT LICENSES TO AFFILIATES. Wyeth may at any time request and
          authorize Trubion to grant licenses within the scope of Section 2.1
          directly to Affiliates of Wyeth by giving written notice designating
          to which Affiliate a direct license is to be granted. Upon receipt of
          any such notice,

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          Trubion shall enter into and sign a separate direct license agreement
          with such designated Affiliate of Wyeth. All such direct license
          agreements shall be consistent with the terms and conditions of this
          Agreement, except for such modifications as may be required by the
          laws and regulations in the country in which the direct license will
          be exercised; provided, however, that Trubion shall have no obligation
          to enter into any such direct license agreement if the effect of
          entering into such agreement (and continuing as a Party to this
          Agreement) would be to increase the level of obligations owed by
          Trubion, decrease the obligations owed to Trubion or the
          enforceability thereof, or decrease the consideration owed to Trubion
          relative to the obligations owed by or to, or the consideration owed
          to, Trubion under this Agreement, had such direct license(s) not been
          granted. In countries where the validity of such direct license
          agreement requires prior government approval or registration, such
          direct license agreement shall not become binding between the parties
          thereto until such approval or registration is granted, which approval
          or registration shall be obtained by Wyeth. All costs of making such
          direct license agreement(s), including Trubion's reasonable attorneys'
          fees, under this Section 2.5 shall be borne solely by Wyeth.

     2.6. RIGHT OF REFERENCE. Trubion hereby grants to Wyeth a "Right of
          Reference," as that term is defined in 21 C.F.R. Section 314.3(b), to
          any data Controlled by Trubion that relates to any CD20 Product (and
          any other Licensed Product, to the extent applicable), and Trubion
          shall provide a signed statement to this effect, if requested by
          Wyeth, in accordance with 21 C.F.R. Section 314.50(g)(3).

     2.7. SECTION 365(N) OF BANKRUPTCY CODE. All rights and licenses now or
          hereafter granted under or pursuant to any Section of this Agreement,
          including Sections 2.1 and 2.5 hereof, are rights to "intellectual
          property" (as defined in Section 101(35A) of Title 11 of the United
          States Code, as amended (such Title 11, the "Bankruptcy Code")). In
          the event this Agreement is rejected under Section 365 of the
          Bankruptcy Code, Trubion hereby grants to Wyeth, subject to Wyeth's
          obligations under Sections 365(n)(2)(A) and (B), a right of access and
          to obtain possession of and to benefit from each of the following
          embodiments to the extent related to Wyeth's exercise of its license
          rights to any Licensed Products or otherwise related to any rights or
          licenses granted under or pursuant to any Section of this Agreement:
          (i) copies of pre-clinical and clinical research data and results,
          (ii) aliquots of laboratory samples, (iii) Licensed Product samples
          and inventory, (iv) Cell Lines expressing Licensed Products, libraries
          encoding Licensed Products or components thereof and sequences
          thereof, (v) copies of laboratory notes and notebooks pertaining to
          Licensed Products, (vi) copies of data and results related to clinical
          trials of Licensed Products, (vii) regulatory filings and approvals of
          Licensed Products, (viii) rights of reference in respect of regulatory
          filings and approvals of Licensed Products, and (ix) plasmid and
          vectors encoding Licensed Product SMIPs,

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          all of which constitute "embodiments" of intellectual property
          pursuant to Section 365(n) of the Bankruptcy Code, and (xi) all other
          embodiments of such intellectual property in Trubion's possession or
          control. Recognizing that the embodiments described above may be
          useful or necessary to Trubion in connection with its continued
          operation of its business, and that a Third Party may also have a
          right of access to such embodiment under Section 365(n) of the
          Bankruptcy Code or applicable non-bankruptcy law, where there is a
          fixed or limited quantity of any biological material or other tangible
          item of such embodiment described above, Wyeth shall be entitled to a
          pro rata portion thereof. Trubion agrees not to interfere with Wyeth's
          exercise under the Bankruptcy Code of rights and licenses to
          intellectual property licensed hereunder and embodiments thereof in
          accordance with this Agreement and agrees to use Commercially
          Reasonable Efforts (short of any obligation of Trubion to incur
          expenses in connection therewith) to assist Wyeth to obtain such
          intellectual property and embodiments thereof in the possession or
          control of Third Parties as reasonably necessary or useful for Wyeth
          to exercise such rights and licenses in accordance with this
          Agreement; provided, however, that Trubion's Commercially Reasonable
          Efforts for purposes of this Section 2.7 shall not be deemed to
          include an obligation to make payments to Third Parties to obtain such
          intellectual property rights and embodiments thereof. The Parties
          hereto acknowledge and agree that reimbursement payments pursuant to
          Sections 3.6 and 4.6 and all other payments by Wyeth to Trubion
          hereunder other than royalty payments pursuant to Section 5.4 and
          Additional Research and Development Expense Payments under Section 5.3
          do not constitute royalties within the meaning of Bankruptcy Code
          Section 365(n) or relate to licenses of intellectual property
          hereunder.

     2.8. NO IMPLIED RIGHTS. Except as expressly provided in this Agreement,
          neither Party shall be deemed by estoppel or implication to have
          granted the other Party any license or other right with respect to any
          intellectual property of such Party.

3.   RESEARCH PROGRAM.

     3.1. SCOPE AND CONDUCT OF THE RESEARCH PROGRAM. Under the terms and
          conditions set forth herein, Trubion and Wyeth shall collaborate
          through one or more joint project teams in the conduct of a
          pre-clinical research program to identify and evaluate (a) SMIPs
          directed against Licensed Targets and (b) Licensed Products, including
          CD20 Products, *** and Other Products (collectively, the "Research
          Program"). Such activities shall include, but not be limited to, the
          following:

               ***

          Subject to and in accordance with the Research Plan and the
          Development Plan (to the extent applicable), the JRC shall determine
          the appropriate

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          activities to be undertaken by Trubion and Wyeth; provided, however,
          that, as of the Signing Date, the Parties anticipate that Trubion
          shall conduct activity (i) above (with input from Wyeth), Wyeth shall
          conduct activities (v), (vi) and (vii) above, and Trubion and Wyeth
          shall jointly conduct activities (ii), (iii) and (iv) above. The
          Research Program shall be conducted in accordance with the Research
          Plan, and each Party shall use its Commercially Reasonable Efforts to
          perform all of its obligations under the Research Program in
          accordance with the Research Plan and current good laboratory
          practices.

     3.2. DESIGNATION OF TARGETS.

          3.2.1. TARGET CANDIDATES. Within thirty (30) days after the Effective
               Date, Wyeth shall provide Trubion's Vice President, Legal Affairs
               & Chief Patent Counsel with a list of up to *** Targets (each a
               "Target Candidate") from which Wyeth shall have the exclusive
               right, until ***, to designate up to *** Wyeth Targets, in
               accordance with the following provisions (subject to Wyeth's
               right under Section 3.2.3 to designate as Wyeth Targets up to ***
               Targets (of the *** Targets that Wyeth may designate as Wyeth
               Targets) that are not Target Candidates at the time of
               selection). In the case of protein Targets that are Target
               Candidates, Wyeth shall designate each such Target Candidate on
               the list by its GenBank accession number provided by the National
               Center for Biotechnology Information ("NCBI") (including any
               nomenclature describing such Target Candidate that is provided
               therewith) or, if an NCBI GenBank accession number is not
               available for such Target Candidate, by its nucleotide and amino
               acid sequences. For the avoidance of doubt, Wyeth may not
               designate as Target Candidates any Targets that are Excluded
               Targets. Subject to the following procedures, Trubion shall not
               undertake any research or Development activities beyond Milestone
               One (as defined on Exhibit 3.2.1 attached hereto) of Trubion's
               internal product development process, or propose to enter into or
               enter into any agreement with any Third Party with respect to any
               SMIP directed against any Target Candidate or with respect to any
               Licensed Product containing such a SMIP, unless and until such
               Target Candidate becomes a Released Target, Excluded Target or
               Provisional Excluded Target. Trubion, through its Legal
               Department, shall maintain a copy of the list of Target
               Candidates in a secure location. Trubion shall take reasonable
               measures and implement reasonable procedures to ensure that only
               its inside attorneys who are employees of its Legal Department
               and its outside patent counsel (collectively, "Trubion Lawyers")
               have knowledge of and access to Wyeth's Target Candidate list.
               The Target Candidate list shall be

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               considered Confidential Information of Wyeth, and except as
               expressly permitted under this Section 3.2 or otherwise under
               this Agreement, Trubion shall not use or disclose the Target
               Candidate list or the information set forth therein to any of its
               Affiliates, to any Third Party, or to any employees, officers or
               agents of Trubion other than Trubion Lawyers. For so long as a
               Target remains a Target Candidate, Trubion, through its Legal
               Department, shall implement reasonable procedures to maintain
               records of all Third Party inquiries to Trubion and Trubion's
               responses to same, relating to the Target Candidate list made
               pursuant to this Section 3.2. The Trubion Legal Department shall
               also maintain the list of Released Targets, Excluded Targets and
               Provisional Excluded Targets in accordance with the provisions of
               Sections 3.2.2 and 3.2.4. In the event of a bona fide dispute
               arising under this Agreement relating to the Target selection
               process described in this Section 3.2, Trubion shall provide to
               an independent Third Party selected by Wyeth and reasonably
               acceptable to Trubion access to the lists of Target Candidates,
               Released Targets, Excluded Targets and Provisional Excluded
               Targets and records and processes related thereto (to the extent
               relevant to the bona fide dispute) maintained by Trubion in
               accordance with this Section 3.2. Such independent Third Party
               may only communicate to Wyeth whether or not the Target selection
               process was properly performed by Trubion's Lawyers.

          3.2.2. RELEASED TARGETS. On or before the ***, Wyeth, by written
               notice to Trubion's Vice President, Legal Affairs & Chief Patent
               Counsel, shall identify *** Target Candidates from the list
               delivered pursuant to Section 3.2.1 (inclusive of any Target
               Candidates that have become Released Targets during such period
               pursuant to Section 3.2.4 hereof), which from the date of such
               identification shall cease to be Target Candidates (each, a
               "Released Target"). At the time that a Target Candidate becomes a
               Released Target, Trubion, subject to Section 2.8, shall be free
               to undertake research and Development activities independent of
               obligations under this Agreement, and to enter into discussions
               or an agreement with a Third Party, with respect to SMIPs
               directed against any such Released Target or any other activities
               in connection with such Released Target. On or before the ***,
               Wyeth, by written notice to Trubion, shall identify such
               additional Target Candidates from the list delivered pursuant to
               Section 3.2.1, if any, as additional Released Targets, such that
               there are no more than *** Target Candidates remaining on the
               list delivered pursuant to Section 3.2.1 (less the number of
               Wyeth Targets that were Target Candidates at the time of
               selection as a Wyeth Target(s) pursuant to Section 3.2.3), which

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               from the date of such identification shall cease to be Target
               Candidates and, thereafter each shall also become a Released
               Target. At the end of the Research Term, all remaining Target
               Candidates, if any, shall become Released Targets.

          3.2.3. WYETH TARGETS. Wyeth Targets shall be designated only from
               either (a) Target Candidates that have not become Released
               Targets, or (b) any other Target (including a Released Target
               that is or becomes available, as described below) that is not
               then an Excluded Target or a Provisional Excluded Target;
               provided, however, that no more than *** of the Targets
               designated by Wyeth as Wyeth Targets may be Targets that are not
               Target Candidates at the time of selection. Subject to the
               foregoing sentence, Wyeth shall designate: (y) *** Target
               Candidates or other Targets as Wyeth Targets on or before ***;
               and (z) up to *** Target Candidates or other Targets (inclusive
               of those designated as Wyeth Targets during the ***) as Wyeth
               Targets on or before the second anniversary of the Effective
               Date; provided, however, if Wyeth does not designate a total of
               *** Wyeth Targets on or before such ***, then the lesser number
               of Wyeth Targets so designated shall be the total number of Wyeth
               Targets under this Agreement unless Wyeth extends the Research
               Program, in which case Wyeth may designate, before ***, one or
               more additional Wyeth Targets (up to a cumulative *** in the
               aggregate). For the avoidance of doubt and subject to the
               following sentence, Wyeth may designate only up to a *** Wyeth
               Targets from the Effective Date of this Agreement through the end
               of the Research Program (even if extended). During the term of
               the Research Program, Wyeth shall have the right to ***; provided
               that *** (a "Replacement Target") must be ***. In the event that
               Wyeth nominates as a Wyeth Target (whether as a proposed initial
               designation of a Wyeth Target or as a replacement designation as
               a Wyeth Target) a Target that is not then a Target Candidate,
               Trubion's Legal Department, within ten (10) business days after
               receiving written notice of such nomination, shall determine and
               advise Wyeth in writing whether such Target is an Excluded Target
               or a Provisional Excluded Target, as described below (and shall
               indicate whether such Target is an Excluded Target or is a
               Provisional Excluded Target). If such Target is an Excluded
               Target or a Provisional Excluded Target, it shall not be eligible
               to be considered a Wyeth Target. If a proposed Replacement Target
               is not an Excluded Target or a Provisional Excluded Target, then
               the JRC shall either approve or disapprove designation of such
               proposed Replacement Target as a Wyeth Target; provided that the
               original Wyeth Target that Wyeth proposes to replace shall be

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               automatically deemed a Released Target upon the JRC's approval of
               the designation of the Replacement Target.

          3.2.4. EXCLUDED TARGETS. Excluded Targets are not eligible to be Wyeth
               Targets for so long as they remain Excluded Targets. The Targets
               deemed "Excluded Targets" as of the Effective Date are set forth
               in Exhibit 3.2.4 attached hereto. Trubion may add additional
               Targets as Excluded Targets or Provisional Excluded Targets
               (which may be selected from Released Targets and other Targets,
               but would not include any Wyeth Targets or any Target Candidate
               that has not become a Released Target) in accordance with the
               following procedures:

               (a)  During the period when ***, and upon the written request of
                    a potential Third Party collaborator and/or licensee of
                    Trubion pertaining to the identification, generation and/or
                    Development of SMIPs directed against a Target or Targets,
                    Trubion's Legal Department shall promptly determine whether
                    or not any of such Targets is a Wyeth Target.

               (b)  With respect to any Target newly submitted by a Party to
                    Trubion's Legal Department hereunder, Trubion's Lawyers will
                    determine whether such submitted Target *** Licensed
                    Targets, Target Candidates, Released Targets, Excluded
                    Targets and Provisional Excluded Targets available to
                    Trubion's Lawyers (each a "Previously Deposited Protein").
                    By way of example only, *** Should Wyeth designate a Target
                    that is not a protein, the Parties agree to negotiate in
                    good faith the procedure for identifying and testing whether
                    a subsequent proposed non-protein Target is the "same as"
                    such designated non-protein Target for purposes of this
                    Section 3.2.

               (c)  If Trubion's Legal Department determines, in accordance with
                    Section 3.2.4(b) above, that any such Target is a Wyeth
                    Target, Trubion shall not proceed with such potential Third
                    Party collaboration or license with respect to such Target.
                    If any of such Targets is not a Wyeth Target or a Target
                    Candidate, such Target shall automatically be deemed a
                    "Provisional Excluded Target". If such Target is a Target
                    Candidate, Trubion shall notify Wyeth in writing of
                    Trubion's request that a Target Candidate be recategorized
                    as a Released Target, in order for Trubion to be able to
                    enter substantive negotiations with such Third Party
                    regarding such Target that is a Target Candidate (i.e.,
                    Trubion shall "Put" such Target Candidate

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                    to Wyeth). Trubion shall have no obligation to notify Wyeth
                    of the identity of such Third Party or the purpose of the
                    proposed collaboration or license. From the date that
                    Trubion "Puts" such Target Candidate to Wyeth, Wyeth shall
                    have *** with respect to such Puts made to Wyeth prior to
                    ***, and shall have *** with respect to such Puts made
                    thereafter, to notify Trubion in writing whether Wyeth
                    designates such Target Candidate as a Wyeth Target or
                    recategorizes such Target Candidate as a Released Target. If
                    Wyeth fails to notify Trubion within such *** period,
                    respectively, then such Target Candidate shall automatically
                    be deemed a Released Target. Any such Released Targets shall
                    be deemed to be Provisional Excluded Targets.

               (d)  If Trubion and such potential Third Party collaborator
                    and/or licensee do not enter into a definitive agreement
                    regarding such Provisional Excluded Target within *** after
                    the date that such Target is deemed a Provisional Excluded
                    Target (such *** being subject to a *** extension by
                    Trubion, if Trubion declares, in writing, to Wyeth that at
                    least one draft definitive agreement has been exchanged
                    between Trubion and such potential Third Party collaborator
                    and/or licensee), thereafter such Provisional Excluded
                    Target would revert to being a Released Target. If Trubion
                    and such potential Third-Party collaborator and/or licensee
                    enter into a definitive agreement within the time period
                    provided above, such Provisional Excluded Target shall be
                    deemed an Excluded Target.

               (e)  During the period when ***, if Trubion itself identifies
                    internally a Target that has progressed to Milestone One (as
                    defined in Exhibit 3.2.1 attached hereto) of Trubion's
                    internal product development process, Trubion's Legal
                    Department shall promptly determine whether or not such
                    Target is a Target Candidate. If such Target is not a Target
                    Candidate, such Target shall be deemed an Excluded Target.
                    If Trubion thereafter abandons work on such Excluded Target,
                    Trubion shall notify Wyeth in writing that Trubion has
                    abandoned work on such Excluded Target and such Excluded
                    Target shall thereafter be deemed a Released Target. If such
                    Target is a Target Candidate, Trubion may Put such Target
                    Candidate to Wyeth. From the date that Trubion Puts such
                    Target Candidate to Wyeth, Wyeth shall have *** with respect
                    to such Puts made to Wyeth prior to ***, and shall have ***
                    with respect to such Puts made thereafter, to notify Trubion
                    in writing whether

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                    Wyeth designates such Target Candidate as a Wyeth Target or
                    recategorizes such Target Candidate as a Released Target. If
                    Wyeth fails to notify Trubion within such ***, respectively,
                    then such Target Candidate shall automatically be deemed a
                    Released Target. Any such Released Target shall be deemed to
                    be Excluded Target. If Trubion thereafter abandons work on
                    any such Excluded Target, Trubion shall notify Wyeth in
                    writing that Trubion has abandoned work on such Excluded
                    Target and such Excluded Target shall thereafter be deemed a
                    Released Target.

               (f)  With respect to the Puts described in (c) and (e) above,
                    Trubion shall not be permitted to Put more than *** Target
                    Candidates to Wyeth during the first *** of the Research
                    Program.

     3.3. TERM AND TERMINATION OF THE RESEARCH PROGRAM.

          3.3.1. RESEARCH TERM. The term of the Research Program (the "Research
               Term") shall begin on the Effective Date and shall continue until
               *** (the "Initial Term"), subject to extension as described
               below. At Wyeth's option (exercisable by providing written notice
               to Trubion no later than *** prior to the end of the Initial Term
               of the Research Program or any extension year thereof), the
               Research Term may be extended for up to *** additional ***
               periods and, thereafter, shall be renewable annually only upon
               mutual written agreement of the Parties.

          3.3.2. TERMINATION OF RESEARCH PROGRAM BY WYETH. Commencing on the
               first anniversary of the Effective Date, Wyeth shall have the
               right to terminate the Research Program, at will, at any time, in
               its entirety, upon one (1) year prior written notice to Trubion;
               provided that Trubion shall have no obligation after the
               effective termination date to complete any Research Program
               activities in connection with any Trubion Target, Wyeth Target,
               SMIP or Licensed Product. Such termination of the Research
               Program shall not constitute termination of this Agreement and
               shall not affect the Parties' rights and obligations under this
               Agreement other than those relating to the Research Program.

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     3.4. JOINT RESEARCH COMMITTEE.

          3.4.1. COMPOSITION. Within thirty (30) days after the Effective Date,
               the Parties shall establish a Joint Research Committee (the
               "JRC") to oversee the Research Program. The JRC will be in effect
               only during the Research Term. The JRC shall be composed of three
               (3) representatives from each Party. Each Party may replace any
               of its representatives at any time upon written notice to the
               other Party. From time to time, the JRC may establish
               subcommittees to oversee particular projects or activities, and
               such subcommittees shall be constituted as the JRC decides.

          3.4.2. RESPONSIBILITIES. The JRC shall be responsible for
               establishing, reviewing and recommending modifications and
               updates to the Research Plan, including the Research Budget, in
               accordance with Section 3.5 hereof, monitoring and reporting to
               the Parties on activities conducted pursuant to the Research
               Plan, and for such other functions as agreed by the Parties.

          3.4.3. MEETINGS. The JRC shall meet as soon as practicable after it is
               established by the Parties and, thereafter, at such additional
               times as the Parties deem appropriate, not less frequently than
               quarterly. Each Party shall designate one of its JRC members as
               its "JRC Liaison" to co-chair meetings, prepare and circulate JRC
               meeting agendas and JRC meeting minutes. The meetings of the JRC
               shall be held in the United States, and shall alternate between
               the Parties' business locations or as otherwise decided by the
               JRC. JRC meetings may be conducted in person, by telephone or by
               videoconference. Each Party shall use reasonable efforts to cause
               its representatives to attend the meetings of the JRC. If a
               representative of a Party is unable to attend a meeting, such
               Party may designate an alternate member to attend such meeting in
               place of the absent member.

          3.4.4. VOTING. Decisions of the JRC shall be made by unanimous
               consent, with each Party having one vote. The JRC may act without
               a meeting if an action by unanimous written consent is signed by
               each Party's JRC Liaison.

          3.4.5. DISPUTE RESOLUTION. If the JRC is unable to reach agreement on
               a matter, the matter may be referred, at the request of either
               Party, for resolution through good faith discussions between
               Wyeth's Executive Vice President of Discovery Research and
               Trubion's Senior Vice President of Research and Development or
               their respective designees. Notwithstanding the foregoing, in the
               event the JRC cannot promptly resolve a disagreement or a

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               voting deadlock regarding the Research Program, Wyeth's Executive
               Vice President of Discovery Research shall have the right to cast
               a tie-breaking vote to resolve any such disagreement or voting
               deadlock, such right and tie-breaking authority being subject to
               the terms and conditions of this Agreement.

          3.4.6. MINUTES. The JRC shall keep accurate and complete minutes of
               its meetings that record all proposals and recommendations made,
               and all actions and decisions taken. The JRC minutes shall not be
               effective until approved in writing by each Party's JRC Liaison.
               All records of the JRC shall be available at all times to each
               Party.

     3.5. RESEARCH PLAN. The Parties shall use their Commercially Reasonable
          Efforts to develop and approve a complete Research Plan (including a
          corresponding Research Budget) within sixty (60) days of the Effective
          Date. The Parties shall ensure that the Research Plan is consistent
          with the terms and conditions of this Agreement, and the Research Plan
          shall not impose obligations on either Party that are inconsistent
          with the terms of this Agreement. The Research Plan shall set forth
          generally (a) the activities to be undertaken by the Parties under the
          Research Program consistent with the terms of Section 3.1, (b) the
          utilization of *** Trubion FTEs in conducting such activities, (c) the
          anticipated schedule on which such activities are to be conducted, (d)
          the desired deliverables to be provided by each Party with respect to
          each Licensed Target that is the subject of the Research Program, and
          (e) the annual budget for non-ordinary expenses (as described in
          Section 3.6.1 below) to be incurred by Trubion under the Research
          Program (the "Research Budget"). The JRC shall review the Research
          Plan, including the Research Budget, on at least an annual basis and
          submit any proposed modifications or updates to the Parties for review
          and approval; any such modifications or updates shall not become
          effective until approved in writing by an authorized officer of each
          of the Parties. The Parties shall review and consider any such
          proposed modifications or updates on an expeditious basis. The Parties
          shall promptly amend the Research Plan from time to time to address
          the performance of the Research Program as it relates to any Licensed
          Targets designated by Wyeth in accordance with Section 3.2 above.

     3.6. FUNDING OF THE RESEARCH PROGRAM.

          3.6.1. RESEARCH FUNDING. During each year of the Research Term (as it
               may be extended), Wyeth shall pay Trubion *** per year for
               services performed in accordance with the Research Plan. Trubion
               shall commit to the Research Program ten (10) FTEs per year to
               provide services in furtherance of the Research Program in
               accordance with the Research Plan. For the avoidance of doubt,
               Trubion may, at its sole expense and

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               discretion, devote more than *** FTEs from time to time to
               provide services in furtherance of the Research Program. The ***
               in research funding described above shall be increased
               automatically once per calendar year by the percentage change in
               the U.S. Consumer Price Index, All Urban Consumers over the
               previous year; provided, however, that no increase shall be
               effective prior to January 1, 2007. ***. Trubion shall provide to
               Wyeth, prior to the first day of each Calendar Quarter, a
               forecast of such expenses (by major expense category, on an
               accrual basis) reimbursable under this Section 3.6.1 which
               Trubion expects to incur during such Calendar Quarter and the
               subsequent three Calendar Quarters, in each case shown by month.
               Other than the foregoing amounts and except as otherwise
               expressly provided in this Agreement, each Party shall be solely
               responsible for its costs and expenses incurred in performing its
               obligations under the Research Program.

          3.6.2. REIMBURSEMENT PAYMENTS. Reimbursement to be made to Trubion by
               Wyeth pursuant to Section 3.6.1 will be made pursuant to invoices
               submitted by Trubion to Wyeth no more often than once with
               respect to any Calendar Quarter, within thirty (30) days of the
               end of such Calendar Quarter. Payment shall be due within
               forty-five (45) days after Wyeth receives such an invoice from
               Trubion. Each invoice must be accompanied by supporting
               documentation sufficiently demonstrating the expense so paid on a
               cash basis (such as receipts for out-of-pocket expenses and other
               written documentation reasonably acceptable to Wyeth) and by a
               certificate executed by Trubion's VP, Finance & Administration,
               of the number of FTEs used by Trubion in such Calendar Quarter in
               performing Trubion's obligations under the Research Program.
               Except as approved in writing in advance by Wyeth, Wyeth shall
               not be obligated to reimburse Trubion for amounts in excess of
               the applicable budgeted amounts in the Research Budget.

          3.6.3. RECORDS AND AUDITS. During the Research Term, Trubion shall
               keep books and accounts of record in connection with the expenses
               reimbursable under Section 3.6.1 hereof in accordance with GAAP
               and in sufficient detail to permit accurate determination of all
               figures necessary for verification of costs to be reimbursed
               hereunder. Trubion shall maintain such cost records for a period
               of at least three (3) years after the end of the calendar year in
               which they were generated in order to enable audit of such
               records as set forth below. Upon thirty (30) days prior written
               notice from Wyeth, Trubion shall permit an independent certified
               public accounting firm of nationally recognized standing selected
               by Wyeth and reasonably acceptable to Trubion, to examine, at
               Wyeth's sole expense, the relevant books and records of Trubion

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               as may be reasonably necessary to verify the amount of
               reimbursable out-of-pocket expenses incurred. An examination by
               Wyeth under this Section 3.6.3 shall occur not more than once in
               any calendar year and shall be limited to the pertinent books and
               records for any calendar year ending not more than thirty six
               (36) months before the date of the request. The accounting firm
               shall be provided access to such books and records at Trubion's
               facility(ies) where such books and records are normally kept and
               such examination shall be conducted during Trubion's normal
               business hours. Trubion may require the accounting firm to sign a
               standard non-disclosure agreement before providing the accounting
               firm access to Trubion's facilities or records. The accounting
               firm shall provide both Trubion and Wyeth a written report
               disclosing whether the certificates and invoices submitted by
               Trubion under Section 3.6.2 are correct or incorrect and the
               specific details concerning any discrepancies. No other
               information shall be provided to Wyeth. If the accounting firm
               determines that the aggregate amount of out-of-pocket expenses
               actually incurred by Trubion was less than the amount reimbursed
               by Wyeth during the period covered by the audit, Trubion shall
               refund the excess payments to Wyeth within thirty (30) days of
               its receipt of the auditor's report so concluding (or, if later,
               within fifteen (15) days after resolution of a bona fide
               objection by Trubion to the findings in such report). If the
               amount to be refunded exceeds more than ten percent (10%) of the
               amount that was properly payable, Trubion shall reimburse Wyeth
               for the cost of the audit. All information of Trubion which is
               subject to review under this Section 3.6.3 shall be deemed to be
               Confidential Information of Trubion subject to the provisions of
               Article 7, and such Confidential Information shall not be
               disclosed to any Third Party or used for any purpose other than
               verifying the information provided by Trubion to Wyeth; provided,
               however, that such Confidential Information may be disclosed to
               Third Parties only to the extent necessary to enforce Wyeth's
               rights under this Agreement, as may be necessary for Wyeth to
               exercise its rights under this Agreement, or as otherwise
               expressly permitted under this Agreement.

     3.7. DATA AND DELIVERABLES. During the Research Term, each Party will use
          Commercially Reasonable Efforts to promptly provide to the other Party
          the data or desired deliverables specified in the Research Plan,
          including, without limitation, (a) SMIPs, Recombinant DNA, and Cell
          Lines, to the extent related to Licensed Targets and/or Licensed
          Products, (b) activity evaluation of the items listed in (a) obtained
          from in vitro or in vivo assays, pharmacology studies, process
          development data, drug product formulation data, toxicology and safety
          studies, and evaluation of chemotherapy conjugates, but only to the
          extent and in the manner that items listed in (a)

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          and (b) are set forth in the Research Plan. Each Party shall also
          disclose to the other Party in writing all data, information,
          inventions, techniques and discoveries (whether patentable or not)
          arising out of the conduct of the Research Program. Disclosure of all
          such aforementioned inventions and discoveries shall be delivered to
          the other Party in a manner mutually agreed upon by the Joint Patent
          Committee. Subject to the terms and conditions of this Agreement, each
          Party shall have the right to use any data or information generated
          under the Research Program for its permitted activities under the
          Research Program and this Agreement (collectively, "Research Program
          Data"). TRUBION MAKES NO REPRESENTATION OR WARRANTY, EITHER EXPRESS OR
          IMPLIED, THAT IT WILL BE ABLE TO SUCCESSFULLY DISCOVER, DEVELOP OR
          DELIVER ANY SMIP DIRECTED AGAINST A LICENSED TARGET OR ANY LICENSED
          PRODUCT.

     3.8. ALLIANCE MANAGERS. Each Party shall designate a single alliance
          manager, who shall perform such duties relating to the day-to-day
          worldwide coordination of the collaboration contemplated by this
          Agreement as are determined by the JRC and the JDC. Such alliance
          managers shall have experience and knowledge appropriate for managers
          with such project management responsibilities. Such alliance managers
          may attend, as non-voting members, any meetings of the committees
          contemplated by this Agreement as deemed fit by such committees. Each
          Party may change its designated alliance manager from time to time
          upon notice to the other Party.

4.   PRODUCT DEVELOPMENT, MANUFACTURING, COMMERCIALIZATION AND REGULATORY
     MATTERS.

     4.1. PRODUCT DEVELOPMENT. Except as otherwise expressly provided in
          Articles 2 and 3 hereof and in this Article 4, Wyeth shall have the
          sole authority, at its expense, for the Development of Licensed
          Products, including the initiation and conduct of clinical trials.
          Wyeth shall be responsible for the Development of and shall use its
          Commercially Reasonable Efforts to Develop Licensed Products
          throughout the Territory where it is Commercially Reasonable to do so
          (it being understood that Wyeth shall have the sole discretion to
          select those countries in which it will conduct clinical studies of
          Licensed Products and, when Commercially Reasonable to do so, to delay
          or discontinue the Development of any Licensed Product directed
          against a particular Licensed Target in favor of pursuing Development
          of another Licensed Product directed against such Licensed Target).
          When appropriate based on the data obtained during Development, Wyeth
          shall use its Commercially Reasonable Efforts to secure Regulatory
          Approval for Licensed Products in the Territory.

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     4.2. TRANSFER OF PRODUCT DATA AND FILINGS. Upon Wyeth's reasonable request
          and in consultation with the JDC from time to time during the term of
          this Agreement and to the extent permitted by applicable law, Trubion
          shall assign and transfer to Wyeth Trubion's entire right, title and
          interest in and to any of the Product Data and Filings pursuant to an
          instrument to such effect in form and substance reasonably
          satisfactory to Wyeth and shall perform all other actions reasonably
          requested by Wyeth to effect and confirm such transfer. The Parties
          shall cooperate through the JDC to ensure that assignment and transfer
          of Trubion's right, title and interest in and to Product Data and
          Filings relating to CD20 Products is made in a manner that does not
          impede Trubion's activities and responsibilities under Section 4.6.
          After receipt of Wyeth's request consistent with the foregoing,
          Trubion shall provide to Wyeth, at Wyeth's expense, within sixty (60)
          days of receipt of such request, complete copies of such Product Data
          and Filings, including, without limitation, relevant clinical data,
          INDs, additional regulatory filings with FDA or other Regulatory
          Authorities, supplements or amendments thereto, all written
          correspondence with FDA or other Regulatory Authorities regarding the
          regulatory filings, and all existing written minutes of meetings and
          memoranda of conversations between Trubion (including, to the extent
          practicable, Trubion's investigators) and FDA or other Regulatory
          Authorities in Trubion's possession (or in the possession of any of
          Trubion's agents and subcontractors, such as contract research
          organizations used by Trubion), to the extent Trubion has the right to
          access and provide to Wyeth such Product Data and Filings, regarding
          such regulatory filings, each to the extent they relate to Licensed
          Products. Within thirty (30) days (or such later date as Wyeth may
          request) after the date of receipt of Wyeth's reasonable request after
          consultation with the JDC, Trubion shall execute and deliver a letter
          to the FDA or other Regulatory Authorities, in a form approved by
          Wyeth, transferring ownership to Wyeth of such regulatory filings, if
          any, filed in the name of Trubion that are related to Licensed
          Products. After such transfer of ownership of regulatory filings
          relating to a Licensed Product, during the term of this Agreement all
          regulatory filings with the FDA or other Regulatory Authorities
          pertaining to such Licensed Product shall be made in the name of
          Wyeth, in accordance with the terms of Section 4.3 below.

     4.3. REGULATORY APPROVALS. Wyeth shall have the sole authority to file, in
          its own name, at its sole expense, all Regulatory Approval
          Applications for Licensed Products. Wyeth shall have the sole
          authority and responsibility for communicating with any Regulatory
          Authority regarding any Regulatory Approval Application, or any
          Regulatory Approval once granted. To the extent necessary to satisfy
          applicable regulatory requirements with respect to the INDs for the
          clinical studies of CD20 Products described in Section 4.6, Wyeth
          hereby grants to Trubion a "Right of Reference," as that term is
          defined in 21 C.F.R. Section 314.3(b), to any data Controlled by Wyeth
          that relates to any CD20 Products that are the subject

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          of the clinical studies described in Section 4.6 hereof, and Wyeth
          shall provide a signed statement to this effect, if requested by
          Trubion, in accordance with 21 C.F.R. Section 314.50(g)(3). Copies of
          all Wyeth regulatory filings that relate to Trubion's Development
          activities under this Agreement will be provided by Wyeth to Trubion
          upon request, subject to reasonable resource and time constraints.

     4.4. REGULATORY REPORTING. Wyeth shall be responsible for preparing and
          filing all reports required to be filed in order to maintain any
          Regulatory Approvals granted for Licensed Products in the Territory,
          including, without limitation, adverse drug experience reports. To the
          extent Trubion has or receives any information regarding any adverse
          drug experience which may be related to the use of any Licensed
          Product or to Licensed Product Development, Trubion shall promptly
          provide Wyeth with all such information in accordance with the Adverse
          Event Reporting and pharmacovigilance procedures set forth in Exhibit
          4.4 attached hereto (as may be amended from time to time upon written
          mutual agreement of the Parties). From time to time after the
          Effective Date, representatives from both Parties shall meet to review
          and revise or replace such Adverse Event Reporting and
          pharmacovigilance procedures.

     4.5. PROGRESS REPORTS.

               (a)  Wyeth shall provide Trubion with confidential summary
                    reports of its and its sublicensees' Development activities,
                    on a Licensed Product-by-Licensed Product basis, on a ***,
                    with respect to CD20 Products and ***, and on an ***, with
                    respect to Other Products. The form of the summary reports,
                    and the type of information and the appropriate and
                    reasonable level of detail to be included in such reports,
                    shall be mutually and reasonably agreed by the Parties;
                    provided that the Parties agree that such reports shall
                    include information regarding progress towards and
                    achievement of any event set forth in Exhibit 5.3 attached
                    hereto.

               (b)  Wyeth shall provide Trubion with confidential summary
                    reports of its and its sublicensees' CD20 Product
                    Commercialization activities on a *** after the First
                    Commercial Sale of a CD20 Product. Beginning *** prior to
                    the anticipated First Commercial Sale of a CD20 Product, and
                    thereafter on a ***, Wyeth shall meet with Trubion and
                    provide updates on CD20 Product Commercialization
                    activities.

               (c)  Wyeth shall provide Trubion with confidential summary
                    reports of its and its sublicensees' *** Commercialization

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                    activities on a *** after the First Commercial Sale of a
                    ***. Beginning *** prior to the anticipated First Commercial
                    Sale of a ***, and thereafter on a ***, Wyeth shall meet
                    with Trubion and provide updates on *** Commercialization
                    activities.

               (d)  Wyeth shall provide Trubion with confidential summary
                    reports of its and its sublicensees' Other Product
                    Commercialization activities on an *** after the First
                    Commercial Sale of an Other Product. Beginning *** prior to
                    the anticipated First Commercial Sale of an Other Product,
                    and thereafter on an ***, Wyeth shall meet with Trubion and
                    provide updates on Other Product Commercialization
                    activities.

               (e)  The meetings described in clauses (b) - (d) above shall be
                    coordinated to occur at the same time, to the extent
                    practicable.

     4.6. CD20 PRODUCT DEVELOPMENT. Subject to Section 4.7 hereof, Trubion shall
          use its Commercially Reasonable Efforts to conduct the following
          Development activities for CD20 Products: (a) Trubion shall continue
          the Phase I Clinical Studies and Phase IIa Clinical Studies of TRU-015
          ongoing at the Effective Date for treatment of rheumatoid arthritis
          until completion or termination of such studies, including the
          re-treatment periods of such studies; (b) Trubion shall initiate and
          perform the planned Phase IIb Clinical Study of TRU-015 for treatment
          of rheumatoid arthritis through the completion or termination of such
          study; (c) Trubion shall continue the Phase I Clinical Study ongoing
          at the Effective Date, and shall initiate and perform the planned
          Phase III Clinical Studies (or the appropriate subsequent clinical
          study) of TRU-015 for the treatment of *** through the completion or
          termination of such studies; (d) Trubion shall have responsibility for
          and shall perform the clinical studies for at least two (2) additional
          Niche Indications selected by the Parties and set forth in the
          Development Plan; and (e) Trubion shall continue to perform the
          ongoing bioprocess development activities, and in each case (a-e) such
          activities and responsibilities of Trubion shall be performed in
          accordance with the Development Plan. None of the clinical studies
          described in this Section 4.6 shall be terminated prior to completion
          before discussion of such matter by the JDC. Trubion shall keep
          accurate records of its clinical study activities under this Section
          4.6 in accordance with applicable laws and, upon reasonable request,
          shall provide Wyeth with access to such records. Trubion shall
          maintain such records for a period of at least three (3) years after
          the end of the calendar year in which they were generated. The
          Development Plan shall provide that Trubion is responsible for
          conducting the clinical trials for rheumatoid arthritis, *** and
          additional Niche Indications through the completion or termination of
          such clinical studies

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          described above and shall contain a budget for such clinical trials.
          Trubion shall be solely responsible for its internal FTE and other
          internal costs for such Development activities, but Wyeth shall
          reimburse Trubion for all out-of-pocket costs incurred by Trubion in
          connection with the foregoing Development activities in accordance
          with the budget contained in the Development Plan (which shall
          include, without limitation, all expenses paid to one or more contract
          research organizations for such Development activities). Trubion shall
          provide to Wyeth, on or before the first day of each Calendar Quarter,
          a forecast of such out-of-pocket costs (by major expense category, on
          an accrual basis) reimbursable under this Section 4.6 that Trubion
          expects to incur during such Calendar Quarter and the subsequent three
          (3) Calendar Quarters, in each case shown by month. Reimbursement to
          be made to Trubion by Wyeth pursuant to this Section 4.6 will be made
          pursuant to invoices submitted by Trubion to Wyeth no more often than
          once with respect to any Calendar Quarter, within forty-five (45) days
          of the end of such Calendar Quarter. Payment shall be due within
          forty-five (45) days after Wyeth receives such an invoice from
          Trubion. Each invoice must be accompanied by supporting documentation
          sufficiently demonstrating the expense so incurred (such as receipts
          for out-of-pocket expenses). The provisions of Section 3.6.3 shall
          apply to the expenses reimbursable by Wyeth under this Section 4.6 in
          the same manner as they apply to expenses reimbursable under Section
          3.6.1.

     4.7. JOINT DEVELOPMENT COMMITTEE. Within thirty (30) days of the Effective
          Date, Wyeth and Trubion shall establish a CD20 Product Joint
          Development Committee (the "JDC"), comprised of appropriate
          representatives of both Parties, to review and provide input to Wyeth
          regarding CD20 Product Development in the Territory, including the
          strategic direction of the overall CD20 Product Development program.
          Wyeth shall consider in good faith any of Trubion JDC members'
          comments and recommendations regarding CD20 Product Development, but
          Wyeth shall have final decision-making authority with respect to how
          the Parties proceed with CD20 Product Development, subject to Wyeth's
          obligations under Section 4.1 in connection therewith. If Trubion
          disagrees with an action or decision by the JDC, Trubion may express
          its concerns through good faith discussions between the Executive
          Officers of Trubion and Wyeth, with Wyeth Research's President having
          the final decision-making authority with respect to such matter. For
          the avoidance of doubt, the JDC may not impose different or greater
          CD20 Product Development obligations on Trubion than those specified
          in Section 4.6.

     4.8. JOINT PROJECT TEAM; DEVELOPMENT PLAN. Trubion and Wyeth shall form a
          Joint Project Team ("JPT") comprised of appropriate representatives of
          both Parties to plan and implement the CD20 Product Development
          activities in accordance with the Development Plan. The JPT shall
          report to the JDC. If the JPT cannot promptly resolve a disagreement
          or a voting deadlock regarding the CD20 Product Development
          activities, the matter

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          shall be brought before the JDC for resolution. Wyeth shall prepare
          the Development Plan with input and advice from Trubion through the
          JPT. The Development Plan will define each Party's roles and
          responsibilities, provide a mechanism to coordinate each Party's
          and/or joint activities, and provide a process for monthly meetings of
          the JPT to monitor and report on all activities of the Parties
          conducted under the Development Plan. The Development Plan shall not
          impose different or greater CD20 Product Development obligations on
          Trubion than those specified in Section 4.6. The Development Plan
          shall be updated annually by the JPT.

     4.9. MANUFACTURING. Wyeth shall have the exclusive right to Manufacture
          Licensed Products itself or through one or more Third Parties selected
          by Wyeth; provided, however, that Trubion shall use its Commercially
          Reasonable Efforts to Manufacture and supply Wyeth with its
          requirements of the TRU-015 Product in accordance with the Development
          Plan under Trubion's existing contract Manufacturing arrangements for
          use in pre-clinical studies and clinical trials ("Clinical Study
          Supplies"); provided that Trubion cannot guarantee as of the Effective
          Date that it will be able to Manufacture and supply such requirements.
          Wyeth shall reimburse Trubion for its direct out-of-pocket cost of
          Clinical Study Supplies, including, without limitation, out-of-pocket
          expenses incurred by Trubion prior to the Effective Date that are
          directly related to the Manufacture, testing and release of Clinical
          Study Supplies to be used after the Effective Date (such pre-Effective
          Date out-of-pocket expenses not to exceed ***). Reimbursement of such
          pre-Effective Date expenses shall be due within thirty (30) days after
          the first patient is dosed in the first Phase IIb Clinical Study for
          rheumatoid arthritis using such Clinical Study Supplies. Upon Wyeth's
          written request, Trubion shall provide reasonable assistance to Wyeth,
          until the first cGMP batch of TRU-015 Product is Manufactured in a
          Wyeth facility (or the facility of a Third Party designated by Wyeth),
          in support and facilitation of Wyeth's efforts to Manufacture TRU-015
          Products and to secure appropriate TRU-015 Product Manufacturing
          arrangements with Third Parties. Such assistance shall be at no cost
          to Wyeth; provided that Wyeth shall reimburse Trubion for all of its
          reasonable out-of-pocket expenses related thereto. If applicable, upon
          Wyeth's written request, Trubion shall assign or otherwise transfer to
          Wyeth (to the extent allowable under such agreements) its TRU-015
          Product Manufacturing agreements with Third Parties.

     4.10. COMMERCIALIZATION. Subject to the terms and conditions of this
          Agreement, Wyeth shall have the sole authority and the exclusive right
          to Commercialize Licensed Products itself or through one or more Third
          Parties selected by Wyeth and shall have sole authority and
          responsibility in all matters relating to the Commercialization of
          Licensed Products. Wyeth shall use Commercially Reasonable Efforts to
          Commercialize Licensed Products in the Territory in each country where
          Wyeth has obtained Regulatory Approval for such Licensed Product(s)
          and for each indication

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          of such Licensed Product(s) for which Regulatory Approval has been
          obtained in such country.

     4.11. CO-PROMOTION OPTION. Subject to the foregoing, in the event of a BLA
          filing with the FDA for Regulatory Approval of a CD20 Product for a
          Niche Indication in the United States, Trubion shall have the option
          to Co-Promote the CD20 Product in the United States for such Niche
          Indication in accordance with Wyeth's marketing plan for up to five
          (5) years after the First Commercial Sale of the first CD20 Product
          for any Niche Indication in the United States (the "Co-Promotion
          Period"). The Trubion Co-Promotion option shall be exercisable by
          Trubion giving written notice to Wyeth no later than *** after the
          date of the first BLA filing with the FDA for the first Niche
          Indication for the first CD20 Product (or such longer time as the
          Parties may mutually agree). Promptly after Trubion's exercise of such
          option, the Parties shall negotiate, in good faith, a definitive
          Co-Promotion Agreement, which shall require Trubion and Wyeth to use
          Commercially Reasonable Efforts to Co-Promote such CD20 Product. Such
          Co-Promotion Agreement shall contain customary provisions relating to
          relative sales force efforts, responsibility for sales calls, sales
          force training, promotional materials and samples, detailing and the
          number and qualifications of sales force personnel (including medical
          science liaisons) that will be devoted to such Co-Promotion
          activities. The Parties hereby agree, inter alia, that such
          Co-Promotion Agreement, and Wyeth's marketing plan for such CD20
          Product, shall provide (a) Trubion's sales force with a meaningful
          role in the Commercialization of such CD20 Product; (b) that Wyeth
          shall provide CD20 Product-related sales training to Trubion's sales
          force, at no cost to Trubion; and (c) that Trubion's sales force shall
          use CD20 Product promotional materials and samples, to be provided by
          Wyeth at no cost, in connection with their sales efforts. As
          compensation for sales force support provided by Trubion in connection
          with such Co-Promotion, Wyeth shall pay Trubion a fixed fee (to be set
          forth in the definitive Co-Promotion Agreement) for each Product sales
          detail performed by members of Trubion's sales force in accordance
          with Wyeth's marketing plan for such CD20 Product. Trubion will not
          have the right to contract out for or otherwise delegate to any Third
          Party any responsibility for such sales force support. Trubion's sales
          force activities shall be conducted in accordance with Wyeth's
          policies and the marketing and promotion plan for the CD20 Product.

     4.12. CO-PROMOTION COMMITTEE. If Trubion exercises its Co-Promotion option
          with respect to a CD20 Product in accordance with Section 4.11 hereof,
          a Co-Promotion Committee shall be formed by the Parties within thirty
          (30) days after such exercise. The Co-Promotion Committee shall
          oversee all aspects of Co-Promotion-related activities and reasonably
          relevant aspects of Commercialization of such CD20 Product during the
          Co-Promotion Period, and shall include Trubion's Chief Executive
          Officer and Wyeth's Executive Vice President and General Manager,
          Wyeth BioPharma.

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     4.13. CO-BRANDING. To the extent allowed by applicable law, all product
          labeling for CD20 Products shall include both Parties' names, which
          shall be of similar size and prominence to the extent practicable
          (except (i) with respect to labeling of vials or other components of a
          CD20 Product that do not include either Party's name or (ii) with
          respect to labeling of diluent or other components packaged together
          with the CD20 Product that do not customarily contain another Person's
          name).

     4.14. MARKING. All Licensed Products shall be marked with the patent
          numbers of issued patents within Trubion Patent Rights and Wyeth
          Patent Rights that cover such Licensed Products, to the extent
          practicable and permitted by law in countries in which such markings
          have notice value against infringers of patents.

5.   CONSIDERATION.

     5.1. INITIAL RESEARCH AND DEVELOPMENT EXPENSE PAYMENT. In consideration of
          Trubion's agreement to conduct the Research Program and to participate
          on the JRC and JDC, Wyeth shall pay to Trubion Forty Million Dollars
          ($40,000,000.00) within ten (10) days after the Effective Date, which
          payment shall be non-refundable and non-creditable.

     5.2. EQUITY. Wyeth shall purchase from Trubion common stock of Trubion at
          such time, in such amounts and for such price as specified in the
          Stock Purchase Agreement, attached hereto as Exhibit 5.2A. Concurrent
          with the execution of the Stock Purchase Agreement, the Parties shall
          enter into an amendment of Trubion's Amended and Restated Investor
          Rights Agreement, attached hereto as Exhibit 5.2B.

     5.3. ADDITIONAL RESEARCH AND DEVELOPMENT EXPENSE PAYMENTS. In further
          consideration of Trubion's contributions under the Research Program
          and the Development Program, as provided in Articles 3 and 4 above,
          Wyeth shall pay to Trubion the payments specified in Exhibit 5.3
          attached hereto (each an "Additional Research and Development Expense
          Payment") in the amounts and at such times as specified in Exhibit
          5.3. Wyeth shall notify Trubion promptly upon the achievement of each
          event specified in Exhibit 5.3.

     5.4. ROYALTIES.

               5.4.1. LICENSED PRODUCT ROYALTIES. In consideration for the
                    licenses granted to Wyeth under Section 2.1 hereof, and in
                    addition to those payments required to be made by Wyeth
                    pursuant to Section 5.1, Section 5.2 and Section 5.3, Wyeth
                    shall pay to Trubion royalties during the Royalty Period as
                    set forth in Sections 5.4.2, 5.4.3 and 5.4.4 below, subject
                    to the adjustments provided in Section 5.4.6 below.

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               5.4.2. CD20 PRODUCT ROYALTIES.

                    (a)  Except as provided in Sections 5.4.2(b) and 5.4.2(c)
                         below, Wyeth shall pay to Trubion royalties in the
                         amount of the Marginal Royalty Rates (set forth below)
                         of the aggregate Net Sales collectively obtained by
                         Wyeth and its sublicensees from the sale of CD20
                         Products in the Territory during each calendar year in
                         the applicable Royalty Period:

<TABLE>
<CAPTION>
                               Marginal Royalty Rate
                         (% of the Applicable Portion of
Annual Net Sales Level           Annual Net Sales)
----------------------   -------------------------------
<S>                      <C>
Less than ***                           ***
From ***                                ***
From ***                                ***
From ***                                ***
Greater than ***                        ***
</TABLE>

                         Each Marginal Royalty Rate set forth in the table above
                         shall apply only to that portion of the annual Net
                         Sales that falls within the indicated range. By way of
                         example only, if the aggregate Net Sales of CD20
                         Products during a calendar year equaled ***, the total
                         royalty for CD20 Products during such year would equal
                         the specified Marginal Royalty Rate (***) of the first
                         *** of Net Sales, plus the specified Marginal Royalty
                         Rate (***) of the next *** of Net Sales, plus the
                         specified Marginal Royalty Rate (***) of the remaining
                         *** of Net Sales (that is, ***, which would equal ***).

                         For purposes of this Section 5.4.2, the "CD20 Effective
                         Royalty Rate" for a particular time period shall mean
                         the weighted average, expressed as a percentage, of the
                         Marginal Royalty Rates that would apply under the
                         provisions of this Section 5.4.2(a) to the aggregate
                         CD20 Product Net Sales in the Territory during such
                         time period (without regard, for these purposes, to any
                         adjustments made under Sections 5.4.2(b) or 5.4.2(c)).
                         By way of example only, if the aggregate Net Sales of
                         CD20 Products in the Territory during a calendar year
                         equaled ***, the CD20 Effective Royalty Rate for such
                         calendar year would be calculated as follows: ((*** of
                         ***) plus (*** of ***) plus (*** of ***)) divided by
                         ***, expressed as a percentage, which would equal ***.
                         By way of further example only, if the aggregate Net
                         Sales of CD20 Products in the Territory during each of
                         the four Calendar Quarters

                                                                              40

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                         of such calendar year were ***, respectively (for a
                         total of ***), the CD20 Effective Royalty Rates for
                         each of the four Calendar Quarters would be ***,
                         respectively.

                    (b)  Subject to the provisions of Section 5.4.2(c) below, in
                         the event that, at any time during the term of the
                         Product License, no issued Valid Claim is included
                         within the Trubion Patent Rights in a country where a
                         CD20 Product is sold (which claim, but for the licenses
                         granted hereunder to Wyeth, would be infringed by
                         Wyeth's or its sublicensees' Manufacture, use, sale,
                         offer for sale or import of such CD20 Product in such
                         country), Wyeth shall pay to Trubion royalties with
                         respect to such CD20 Product in such country during
                         such time period, in lieu of the royalties described in
                         Section 5.4.2(a), equal to the following amount: (i)
                         the CD20 Effective Royalty Rate of the aggregate Net
                         Sales obtained by Wyeth and its sublicensees from the
                         sale of such CD20 Product in such country during such
                         time period minus (ii) *** of the aggregate Net Sales
                         obtained by Wyeth and its sublicensees from the sale of
                         such CD20 Product in such country during such time
                         period. By way of example only, if the aggregate Net
                         Sales of such a CD20 Product in such country during the
                         relevant time period were *** and the CD20 Effective
                         Royalty Rate (based on Net Sales of CD20 Products
                         throughout the Territory) for such time period were
                         ***, the royalties payable under this Section 5.4.2(b)
                         on Net Sales in such country would equal (i) ***of ***,
                         (or ***), minus (ii) *** of ***, (or ***), which would
                         equal ***. By way of further example only, if the
                         aggregate Net Sales of such a CD20 Product in such
                         country during the relevant time period were *** and
                         the CD20 Effective Royalty Rate (based on Net Sales of
                         CD20 Products throughout the Territory) for such time
                         period were ***, the royalties payable under this
                         Section 5.4.2(b) on Net Sales in such country would
                         equal (i) *** of ***, (or ***), minus (ii) *** of ***,
                         (or ***), which would equal ***.

                    (c)  In the event that at any time during the term of the
                         Product License: (i) no issued Valid Claim is included
                         within the Trubion Patent Rights in a country where a
                         CD20 Product is sold (which claim, but for the licenses
                         granted hereunder to Wyeth, would be infringed by
                         Wyeth's or its sublicensees' Manufacture, use, sale,
                         offer for sale or import of such CD20 Product in such
                         country), (ii) a product is sold by a Third Party in
                         such country, which product would, if sold by such
                         Third Party in the United

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                         States, infringe an issued Valid Claim included within
                         the Trubion Patent Rights in the United States, and
                         (iii) such product sold by the Third Party has a *** or
                         greater unit market share in such country (where the
                         market is defined as the sum of the unit sales of such
                         CD20 Product and of the product described in clause
                         (ii)), Wyeth shall pay to Trubion royalties with
                         respect to such CD20 Product in such country during
                         such time period, in lieu of the royalties described in
                         Section 5.4.2(a) and Section 5.4.2(b), equal to the
                         following amount: (i) *** of (ii) the CD20 Effective
                         Royalty Rate of the aggregate Net Sales obtained by
                         Wyeth and its sublicensees from the sale of such CD20
                         Product in such country during such time period. By way
                         of example only, if the aggregate Net Sales of such a
                         CD20 Product in such country during the relevant time
                         period were *** and the CD20 Effective Royalty Rate for
                         such time period were ***, the royalties payable under
                         this Section 5.4.2(c) would equal (i) *** of (ii) ***
                         of ***, (or ***), which would equal ***.

               5.4.3. ***.

                    (a)  Except as provided in Sections 5.4.3(b) and 5.4.3(c)
                         below, Wyeth shall pay to Trubion royalties in the
                         amount of the Marginal Royalty Rates (set forth below)
                         of the aggregate Net Sales collectively obtained by
                         Wyeth and its sublicensees from the sale of each *** in
                         the Territory during each calendar year in the
                         applicable Royalty Period:

<TABLE>
<CAPTION>
                               Marginal Royalty Rate
                         (% of the Applicable Portion of
Annual Net Sales Level           Annual Net Sales)
----------------------   -------------------------------
<S>                      <C>
Less than ***                           ***
From ***                                ***
From ***                                ***
From ***                                ***
Greater than ***                        ***
</TABLE>

                         Each Marginal Royalty Rate set forth in the table above
                         shall apply only to that portion of the annual Net
                         Sales for a particular *** that falls within the
                         indicated range. By way of example only, if the
                         aggregate Net Sales of a *** during a calendar year
                         equaled ***, the total royalty for such *** during such
                         calendar year would equal the specified Marginal
                         Royalty Rate (***) of the first *** of Net Sales, plus
                         the specified Marginal Royalty Rate *** of the next ***
                         of Net Sales, plus the specified Marginal Royalty Rate

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                         *** of the remaining *** of Net Sales (that is, ***,
                         which would equal ***).

                         For purposes of this Section 5.4.3, the "*** Royalty
                         Rate" for a particular time period for a particular ***
                         shall mean the weighted average, expressed as a
                         percentage, of the Marginal Royalty Rates that would
                         apply under the provisions of this Section 5.4.3(a) to
                         the Net Sales in the Territory of such *** during such
                         time period (without regard, for these purposes, to any
                         adjustments made under Sections 5.4.3(b) or 5.4.3(c)).
                         By way of example only, if the Net Sales of a *** in
                         the Territory during a calendar year equaled***, the
                         *** Royalty Rate for such calendar year for such ***
                         would be calculated as follows: ((***) plus (***) plus
                         (***)) divided by ***, expressed as a percentage, which
                         would equal ***. By way of further example only, if the
                         Net Sales of such *** in the Territory during each of
                         the four Calendar Quarters of such calendar year were
                         ***, respectively (for a total of *** in such calendar
                         year), the *** Royalty Rates for each of the four
                         Calendar Quarters would be ***, respectively.

                    (b)  Subject to the provisions of Section 5.4.3(c) below, in
                         the event that, at any time during the term of the
                         Product License, no issued Valid Claim is included
                         within the Trubion Patent Rights in a country where a
                         *** is sold (which claim, but for the licenses granted
                         hereunder to Wyeth, would be infringed by Wyeth's or
                         its sublicensees' Manufacture, use, sale, offer for
                         sale or import of such *** in such country), Wyeth
                         shall pay to Trubion royalties with respect to such ***
                         in such country during such time period, in lieu of the
                         royalties described in Section 5.4.3(a), equal to the
                         following amount: (i) the *** Royalty Rate for such ***
                         of the aggregate Net Sales obtained by Wyeth and its
                         sublicensees from the sale of such *** in such country
                         during such time period minus (ii) *** of the aggregate
                         Net Sales obtained by Wyeth and its sublicensees from
                         the sale of such *** in such country during such time
                         period. By way of example only, if the aggregate Net
                         Sales of such a *** in such country during the relevant
                         time period were *** and the *** Royalty Rate (based on
                         Net Sales of such *** throughout the Territory) for
                         such time period for such *** were ***, the royalties
                         payable under this Section 5.4.3(b) on Net Sales in
                         such country would equal (i) ***, (or ***), minus (ii)
                         ***, (or ***), which would equal ***. By way of further
                         example only, if the Net Sales of such *** in such
                         country during the relevant time period were

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<PAGE>

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                         *** and the *** Royalty Rate (based on Net Sales of
                         such *** throughout the Territory) for such time period
                         were ***, the royalties payable under this Section
                         5.4.3(b) on Net Sales in such country would equal (i)
                         ***, (or ***), minus (ii) ***, (or ***), which would
                         equal ***.

                    (c)  In the event that at any time during the term of the
                         Product License: (i) no issued Valid Claim is included
                         within the Trubion Patent Rights in any country where a
                         *** is sold (which claim, but for the licenses granted
                         hereunder to Wyeth, would be infringed by Wyeth's or
                         its sublicensees' Manufacture, use, sale, offer for
                         sale or import of such *** in such country), (ii) a
                         product is sold by a Third Party in such country, which
                         product would, if sold by such Third Party in the
                         United States, infringe an issued Valid Claim included
                         within the Trubion Patent Rights in the United States,
                         and (iii) such product sold by a Third Party has a ***
                         or greater unit market share in such country (where the
                         market is defined as the sum of the unit sales of such
                         *** and of the product described in clause (ii)), Wyeth
                         shall pay to Trubion royalties with respect to such ***
                         in such country during such time period, in lieu of the
                         royalties described in Section 5.4.3(a) and Section
                         5.4.3(b), equal to the following amount: (i) *** of
                         (ii) the *** Royalty Rate for such *** of the aggregate
                         Net Sales obtained by Wyeth and its sublicensees from
                         the sale of such *** in such country during such time
                         period. By way of example only, if the aggregate Net
                         Sales of such a *** in such country during the relevant
                         time period were *** and the *** Royalty Rate for such
                         time period for such *** were ***, the royalties
                         payable under this Section 5.4.3(c) on Net Sales in
                         such country would equal (i) *** of (ii) *** of ***,
                         (or ***), which would equal ***. By way of further
                         example only, if the Net Sales of such *** in such
                         country during the relevant time period were *** and
                         the *** Royalty Rate (based on Net Sales of such ***
                         throughout the Territory) for such time period were
                         ***, the royalties payable under this Section 5.4.3(c)
                         on Net Sales in such country would equal (i) ***
                         multiplied by (ii) *** of ***, (or ***), which would
                         equal ***.

               5.4.4. OTHER PRODUCT ROYALTIES.

                    (a)  Except as provided in Sections 5.4.4(b) and 5.4.4(c)
                         below, Wyeth shall pay Trubion a royalty of *** of the
                         aggregate Net Sales obtained by Wyeth and its
                         sublicensees from the

                                                                              44

<PAGE>

                                                                   REDACTED COPY

                         sale of each Other Product in the Territory during each
                         calendar year in the applicable Royalty Period.

                    (b)  Subject to the provisions of Section 5.4.4(c) below, in
                         the event that, at any time during the term of the
                         Product License, no issued Valid Claim is included
                         within the Trubion Patent Rights in a country where an
                         Other Product is sold (which claim, but for the
                         licenses granted hereunder to Wyeth, would be infringed
                         by Wyeth's or its sublicensees' Manufacture, use, sale,
                         offer for sale or import of such Other Product in such
                         country), Wyeth shall pay to Trubion, with respect to
                         such Other Product in such country during such time
                         period, in lieu of the royalty described in Section
                         5.4.4(a), a royalty of *** of the aggregate Net Sales
                         obtained by Wyeth and its sublicensees from the sale of
                         such Other Product in such country during such time
                         period.

                    (c)  In the event that at any time during the term of the
                         Product License: (i) no issued Valid Claim is included
                         within the Trubion Patent Rights in any country where
                         an Other Product is sold (which claim, but for the
                         licenses granted hereunder to Wyeth, would be infringed
                         by Wyeth's or its sublicensees' Manufacture, use, sale,
                         offer for sale or import of such Other Product in such
                         country), (ii) a product is sold by a Third Party in
                         such country, which product would, if sold by such
                         Third Party in the United States, infringe an issued
                         Valid Claim included within the Trubion Patent Rights
                         in the United States, and (iii) such product sold by a
                         Third Party has a *** or greater unit market share in
                         such country (where the market is defined as the sum of
                         the unit sales of such Other Product and of the product
                         described in clause (ii)), Wyeth shall pay to Trubion,
                         with respect to such Other Product in such country
                         during such time period, in lieu of the royalties
                         described in Section 5.4.4(a) and Section 5.4.4(b), a
                         royalty of *** of the aggregate Net Sales obtained by
                         Wyeth and its sublicensees from the sale of such Other
                         Product in such country during such time period.

               5.4.5. EXPIRATION OF ROYALTY PERIOD. After the expiration of the
                    Royalty Period for any Licensed Product in any country in
                    the Territory, no further royalties shall be payable in
                    respect of sales of such Licensed Product in such country
                    and thereafter the licenses granted to Wyeth under Section
                    2.1 with respect to such Licensed Product in such country
                    shall be fully paid-up, perpetual, irrevocable,
                    royalty-free, exclusive licenses.

                                                                              45

<PAGE>

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               5.4.6. ROYALTY ADJUSTMENTS.

                    (a)  CERTAIN THIRD PARTY AGREEMENTS. On a country-by-country
                         basis in a given calendar year, Wyeth shall deduct from
                         CD20 Product royalties otherwise payable to Trubion
                         under Section 5.4.2 *** of the aggregate amount of
                         royalties actually paid to Third Parties under
                         Additional Third Party Licenses with respect to the
                         Development, Manufacture or Commercialization of CD20
                         Products in such country in such calendar year;
                         provided, however, that (i) the amount of such
                         deduction shall not exceed *** of the amount of the
                         CD20 Product royalties otherwise payable to Trubion
                         under Section 5.4.2 in a given calendar year and (ii)
                         such deduction shall not have the effect, under any
                         circumstances, of reducing the CD20 Product royalties
                         payable under Section 5.4.2 below *** of the aggregate
                         Net Sales obtained by Wyeth and its sublicensees from
                         the sale of CD20 Products in such country in a given
                         calendar year (before taking into account the operation
                         of Sections 5.4.2(b) and 5.4.2(c)). On a
                         country-by-country basis in a given calendar year,
                         Wyeth shall deduct from *** royalties otherwise payable
                         to Trubion under Section 5.4.3 *** of the aggregate
                         amount of royalties actually paid to Third Parties
                         under Additional Third Party Licenses with respect to
                         the Development, Manufacture or Commercialization of
                         such *** in such country in such calendar year;
                         provided, however, that (i) the amount of such
                         deduction shall not exceed *** of the amount of the ***
                         royalties otherwise payable to Trubion under Section
                         5.4.3 in a given calendar year and (ii) such deduction
                         shall not have the effect, under any circumstances, of
                         reducing the *** royalties payable under Section 5.4.3
                         below *** of the aggregate Net Sales obtained by Wyeth
                         and its sublicensees from the sale of such *** in such
                         country in a given calendar year (before taking into
                         account the operation of Sections 5.4.3(b) and
                         5.4.3(c)). ***

                    (b)  OTHER THIRD PARTY AGREEMENTS. Wyeth shall be solely
                         responsible for all payment obligations related to ***.
                         Trubion shall be solely responsible for all payment
                         obligations related to ***.

     5.5. REPORTS AND PAYMENTS.

               5.5.1. CUMULATIVE ROYALTIES. The obligation to pay royalties
                    under Section 5.4 of this Agreement shall be imposed only
                    once with respect to a single unit of a Licensed Product,
                    regardless of how

                                                                              46

<PAGE>

                                                                   REDACTED COPY

                    many Valid Claims included within the Trubion Technology
                    would, but for this Agreement, be infringed by the
                    Manufacture, use, import, offer for sale or sale of such
                    Licensed Product in the countr(y)ies of such Manufacture,
                    use or sale. For the avoidance of doubt, if a single
                    Licensed Product is both a CD20 Product and an Other
                    Product, such Licensed Product shall be deemed to be a CD20
                    Product for purposes of the royalty obligations under
                    Section 5.4. If a single Licensed Product is both a *** and
                    an Other Product, such Licensed Product shall be deemed to
                    be a *** for purposes of the royalty obligations under
                    Section 5.4.

               5.5.2. ROYALTY STATEMENTS AND PAYMENTS. Within *** after the end
                    of each Calendar Quarter, Wyeth shall deliver to Trubion a
                    report setting forth for such Calendar Quarter the following
                    information, on a Licensed Product-by-Licensed Product and
                    country-by-country basis: (a) the gross sales amount (by
                    Wyeth and its sublicensees) for each category of Licensed
                    Product sold in the United States and the number of units of
                    Licensed Product sold in the United States and other
                    countries in the Territory, on a country-by-country basis;
                    (b) the Net Sales for each Licensed Product; (c) any
                    adjustments (including the basis therefor) made pursuant to
                    Sections 5.4.2(b), 5.4.2(c), 5.4.3(b), 5.4.3(c), 5.4.4(b),
                    5.4.4(c) or 5.4.6(a) to the royalty amount payable for the
                    sale of each Licensed Product, the applicable Marginal
                    Royalty Rates and the CD20 Effective Royalty Rate or ***
                    Royalty Rate (as the case may be) payable on the Net Sales,
                    and (d) the royalty amount due hereunder for the sale of
                    each Licensed Product. No such reports shall be due for any
                    Licensed Product before the First Commercial Sale of such
                    Licensed Product. The total royalty due for the sale of
                    Licensed Products during such Calendar Quarter shall be
                    remitted at the time such report is made.

               5.5.3. TAXES AND WITHHOLDING. All payments due Trubion under this
                    Agreement will be made without any deduction or withholding
                    for or on account of any tax unless such deduction or
                    withholding is required by applicable laws or regulations to
                    be assessed against Trubion. If Wyeth is so required to
                    deduct or withhold, Wyeth will (a) promptly notify Trubion
                    of such requirement, (b) pay to the relevant authorities the
                    full amount required to be deducted or withheld promptly
                    upon the earlier of determining that such deduction or
                    withholding is required or receiving notice that such amount
                    has been assessed against Trubion, (c) promptly forward to
                    Trubion an official receipt (or certified copy) or other
                    documentation reasonably acceptable to Trubion evidencing
                    such payment to such authorities, and (d) otherwise
                    reasonably cooperate with Trubion in connection with

                                                                              47

<PAGE>

                                                                   REDACTED COPY

                    Trubion's attempts to obtain favorable tax treatment and
                    credit therefor (where appropriate) in accordance with
                    applicable laws.

               5.5.4. CURRENCY. All amounts payable and calculations hereunder
                    shall be in United States Dollars. As applicable, Net Sales
                    and any royalty deductions shall be translated into United
                    States dollars in accordance with Wyeth's customary and
                    usual translation procedures, consistently applied, which
                    procedures are in accordance with Generally Accepted
                    Accounting Principles in the United States.

               5.5.5. ADDITIONAL PROVISIONS RELATING TO ROYALTIES. Trubion
                    acknowledges and agrees that nothing in this Agreement
                    (including, without limitation, any exhibits or attachments
                    hereto) shall be construed as representing an estimate or
                    projection of either (a) the number of Licensed Products
                    that will or may be successfully Developed or Commercialized
                    or (b) anticipated sales or the actual value of any Licensed
                    Product and that the figures set forth in Section 5.4 or
                    elsewhere in this Agreement or that have otherwise been
                    discussed by the Parties are merely intended to define
                    Wyeth's royalty obligations to Trubion in the event such
                    sales performance is achieved. WYETH MAKES NO REPRESENTATION
                    OR WARRANTY, EITHER EXPRESS OR IMPLIED, THAT IT WILL BE ABLE
                    TO SUCCESSFULLY DEVELOP OR COMMERCIALIZE ANY LICENSED
                    PRODUCT OR, IF COMMERCIALIZED, THAT IT WILL ACHIEVE ANY
                    PARTICULAR SALES LEVEL OF SUCH LICENSED PRODUCT(S).

               5.5.6. INTEREST ON PAST DUE PAYMENTS. If either Party fails to
                    pay any payment due under this Agreement on or before the
                    date such payment is due, as provided in this Agreement,
                    such late payment shall bear interest, to the extent
                    permitted by applicable law, *** as reported from time to
                    time in The Wall Street Journal, effective for the first
                    date on which payment was delinquent and calculated on the
                    number of days such payment is overdue or, if such rate is
                    not regularly published, as published in such source as the
                    Parties agree.

     5.6. MAINTENANCE OF RECORDS; AUDITS.

               5.6.1. RECORD KEEPING. Wyeth shall keep accurate books and
                    accounts of record in connection with the sale of Licensed
                    Products, in sufficient detail to permit accurate
                    determination of all figures necessary for verification of
                    royalties and other payments to be paid to Trubion
                    hereunder. Wyeth shall keep accurate records of its
                    activities under this Agreement that relate

                                                                              48

<PAGE>

                                                                   REDACTED COPY

                    to the events with respect to which Additional Research and
                    Development Expense Payments may be made under Section 5.3
                    hereof. Wyeth shall maintain such records for a period of at
                    least three (3) years after the end of the calendar year in
                    which they were generated.

               5.6.2. AUDITS. Upon thirty (30) days prior written notice from
                    Trubion, Wyeth shall permit an independent certified public
                    accounting firm of nationally recognized standing selected
                    by Trubion and reasonably acceptable to Wyeth, to examine,
                    at Trubion's sole expense, the relevant books and records of
                    Wyeth as may be reasonably necessary to verify the accuracy
                    of the reports submitted by Wyeth in accordance with Section
                    5.5 and the payment of royalties hereunder. An examination
                    by Trubion under this Section 5.6.2 shall occur not more
                    than once in any calendar year and shall be limited to the
                    pertinent books and records for any calendar year ending not
                    more than three (3) years before the date of the request.
                    The accounting firm shall be provided access to such books
                    and records at Wyeth's facility(ies) where such books and
                    records are normally kept and such examination shall be
                    conducted during Wyeth's normal business hours. Wyeth may
                    require the accounting firm to sign a standard
                    non-disclosure agreement before providing the accounting
                    firm access to Wyeth's facilities or records. Upon
                    completion of the audit, the accounting firm shall provide
                    both Wyeth and Trubion a written report disclosing whether
                    the reports submitted by Wyeth are correct or incorrect,
                    whether the royalties paid are correct or incorrect, and in
                    each case, the specific details concerning any
                    discrepancies. No other information shall be provided to
                    Trubion.

               5.6.3. UNDERPAYMENTS/OVERPAYMENTS. If such accounting firm
                    concludes that additional royalties were due to Trubion,
                    Wyeth shall pay to Trubion the additional royalties within
                    thirty (30) days of the date Wyeth receives such
                    accountant's written report so concluding. If such royalty
                    underpayment exceeds ten percent (10%) of the royalties that
                    were to be paid to Trubion, Wyeth also shall reimburse
                    Trubion for the out-of-pocket expenses incurred in
                    conducting the audit. If such accounting firm concludes that
                    Wyeth overpaid royalties to Trubion, Trubion, within thirty
                    (30) days of the date Trubion receives such account's report
                    so concluding, will refund such overpayments to Wyeth less
                    the reasonable out-of-pocket costs incurred by Trubion in
                    conducting the audit.

               5.6.4. CONFIDENTIALITY. All financial information of Wyeth which
                    is subject to review under this Section 5.6 shall be deemed
                    to be

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                    Wyeth's Confidential Information subject to the provisions
                    of Article 7 hereof, and Trubion shall not disclose such
                    Confidential Information to any Third Party or use such
                    Confidential Information for any purpose other than
                    verifying payments to be made by Wyeth to Trubion hereunder;
                    provided, however, that such Confidential Information may be
                    disclosed by Trubion to Third Parties only to the extent
                    necessary to enforce Trubion's rights under this Agreement.

6.   INTELLECTUAL PROPERTY.

     6.1. INVENTIONS; JOINT PATENT COMMITTEE.

          6.1.1. OWNERSHIP AND INVENTORSHIP. A Party shall own all inventions
               and Know-How made solely by employees of such Party, and shall
               jointly own with the other Party any invention, whether or not
               patentable, made jointly by employees of both Parties (a "Joint
               Invention"), all Joint Patent Rights directed thereto, and any
               Know-How made jointly by employees of both Parties ("Joint
               Know-How"). All determinations of inventorship under this
               Agreement shall be made in accordance with United States patent
               law. Each Party shall disclose promptly in writing to the other
               any Joint Inventions and any candidate Joint Inventions of which
               it becomes aware. Subject to (a) the grant of licenses to Wyeth
               under Section 2.1 and to Trubion under Section 2.2, (b) the
               exclusivity provisions of Section 2.3, and (c) the Parties' other
               rights and obligations under this Agreement, each Party shall be
               free to exploit (including to research, Develop, Manufacture,
               Commercialize and enforce), either itself or through the grant of
               licenses to Third Parties (which Third Party licenses are further
               sublicensable), Joint Patent Rights and Joint Know-How throughout
               the world without restriction, without the need to obtain further
               consent from the other Party, and without payment of any
               compensation to the other Party.

          6.1.2. SMIP IMPROVEMENTS. All SMIP Improvements made by Wyeth, whether
               independently or jointly with Trubion, in the course of
               performing Wyeth's obligations under this Agreement during the
               term of the Agreement (each, a "Covered SMIP Improvement") shall
               be promptly disclosed by Wyeth to Trubion. Wyeth, subject to the
               rights and licenses granted by Trubion to Wyeth hereunder, hereby
               grants to Trubion a worldwide, royalty-free (other than as
               expressly set forth in this Section 6.1.2), irrevocable,
               non-exclusive license (with the right to sublicense), under
               Wyeth's rights to such Covered SMIP Improvements, to practice,
               exploit and use such Covered SMIP Improvements in connection with
               the research, Manufacture, Development, Commercialization or use
               of SMIPs

                                                                              50

<PAGE>

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               (***); provided, however, for the avoidance of doubt, that the
               license granted to Trubion pursuant to this sentence shall not be
               deemed to constitute or include a license with respect to any
               underlying Wyeth technology or any Wyeth Technology (including
               without limitation Manufacturing, delivery, formulation and
               conjugation technology) other than Wyeth's rights to such Covered
               SMIP Improvements. In the event, and to the extent, that Wyeth is
               obligated to pay a Third Party any royalties or other payments as
               a result of the licensing of a Covered SMIP Improvement to
               Trubion pursuant to this Section 6.1.2 or as a result of
               Trubion's or its sublicensees' (excluding Wyeth's) practice of
               such Covered SMIP Improvement, the license by Wyeth to Trubion
               pursuant to this Section 6.1.2 with respect to such Covered SMIP
               Improvement shall be conditioned on Trubion's continuing
               obligation to pay Wyeth the amount of such royalties and other
               payments according to the terms of the applicable agreement
               between Wyeth and such Third Party. In the event that Trubion
               grants a sublicense to any Third Party with respect to a Covered
               SMIP Improvement that is not a Joint Invention (but rather was
               invented solely by Wyeth), Trubion shall pay Wyeth a royalty of
               *** of the net sales by such sublicensee (or its affiliates or
               sublicensees) of any product that incorporates such Covered SMIP
               Improvement. For purposes of the preceding sentence, "net sales"
               shall be defined in a manner substantially similar to the
               definition of "Net Sales" under this Agreement.

          6.1.3. JOINT PATENT COMMITTEE.

               (a)  ESTABLISHMENT; MEETINGS; DECISIONS. Within thirty (30) days
                    after the Effective Date, the Parties shall establish a
                    Joint Patent Committee composed of at least one (1)
                    representative from each Party with experience in the
                    prosecution of biotechnology patents. The Joint Patent
                    Committee will have such duties and responsibilities as are
                    expressly assigned to it under this Article 6. The Joint
                    Patent Committee shall meet as soon as practicable after it
                    is established by the Parties and, thereafter, at such
                    additional times as the Parties deem appropriate, not less
                    frequently than quarterly. The meetings of the Joint Patent
                    Committee shall alternate between the Parties' business
                    locations or as otherwise decided by the Joint Patent
                    Committee; provided that Joint Patent Committee meetings may
                    be conducted in person, by telephone or by videoconference.
                    Each Party shall use reasonable efforts to cause its
                    representative(s) to attend each Joint Patent Committee
                    meeting. Decisions of the Joint Patent Committee shall be
                    made by unanimous consent, with each

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                    Party having one vote. The Joint Patent Committee may act
                    without a meeting if an action by unanimous written consent
                    is signed by each committee member. If the Joint Patent
                    Committee is unable to reach agreement on a matter for which
                    it has decision-making authority pursuant to Section
                    6.1.3(b), 6.2.1(c) or 6.2.2(c), the matter may be referred,
                    at the request of either Party, for resolution by outside
                    patent counsel mutually selected by the Parties (wherein
                    such outside patent counsel shall be knowledgeable and
                    experienced in the subject matter of the matter so
                    referred), and such resolution shall be deemed the decision
                    of the Joint Patent Committee. Unless otherwise agreed by
                    the Parties, the patent counsel selected will not have
                    served as primary outside IP counsel to either Party prior
                    to being selected to resolve the Joint Patent Committee
                    disagreement. ***

               (b)  CATEGORY 1 COVERED SMIP IMPROVEMENTS AND CATEGORY 2 COVERED
                    SMIP IMPROVEMENTS. Without limiting Wyeth's obligation under
                    Section 6.1.1 and Section 6.1.2 to disclose promptly to
                    Trubion any inventions and candidate inventions made
                    hereunder (including, without limitation, any Covered SMIP
                    Improvements), each Party shall report on a quarterly basis
                    to the Joint Patent Committee whether any of its activities
                    hereunder during the prior Calendar Quarter involved a new
                    Covered SMIP Improvement. The Joint Patent Committee shall
                    decide whether a given Covered SMIP Improvement (i) is
                    solely applicable to SMIP coding regions (a "Category 1
                    Covered SMIP Improvement"), or (ii) is not solely applicable
                    to SMIP coding regions (a "Category 2 Covered SMIP
                    Improvement"). ***.

6.2. PATENT RIGHTS.

          6.2.1. FILING, PROSECUTION AND MAINTENANCE OF PATENT RIGHTS.

               (a)  TRUBION PATENT RIGHTS.

                    (i)  TRUBION PATENT RIGHTS. Trubion shall use its
                         Commercially Reasonable Efforts to prepare, file,
                         prosecute and maintain, throughout the Territory, all
                         of the Trubion Patent Rights, using patent counsel of
                         Trubion's choice; provided, however, that Trubion shall
                         give Wyeth before filing a reasonable opportunity to
                         review and comment upon the text of any applications
                         for Trubion Patent Rights to the

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                         extent related to any Licensed Product, any SMIPs
                         directed against any Licensed Target, or the
                         Development, Manufacture, use or Commercialization
                         thereof (collectively, "Product-Related Patent
                         Rights"); and provided further, however, that patent
                         counsel for patent applications for Product-Related
                         Patent Rights that are prepared or filed on or after
                         the Signing Date and that do not rely on the priority
                         date of a patent or patent application filed before the
                         Signing Date will be mutually agreed upon by the
                         Parties. Trubion shall reasonably consider and address
                         Wyeth's comments on patent applications included in
                         Product-Related Patent Rights. Trubion shall consult
                         with Wyeth with respect to such patent applications,
                         and shall supply Wyeth with a copy of such patent
                         applications as filed, together with notice of each
                         filing date and serial number. Trubion shall also keep
                         Wyeth advised of the status of prosecution of all such
                         patent applications included in the Product-Related
                         Patent Rights, and shall consult with Wyeth and provide
                         Wyeth with a reasonable opportunity to comment on all
                         correspondence received from and all submissions to be
                         made to any government patent office or authority with
                         respect to any such patent application or patent.
                         Trubion shall reasonably consider and address Wyeth's
                         comments on such correspondence and submissions. Each
                         Party shall be responsible for *** of Trubion's
                         out-of-pocket expenses incurred in connection with
                         preparing, filing, prosecuting and maintaining such
                         Product-Related Patent Rights throughout the Territory,
                         including, but not limited to, out-of-pocket expenses
                         for inventorship determinations and inventorship
                         disputes (other than between the Parties); provided,
                         however, that in the event Trubion grants a license(s)
                         in a given country or countries to one or more Third
                         Parties under any patent application or patent that is
                         included in the Product-Related Patent Rights, Wyeth
                         shall be responsible for a pro rata portion, based on a
                         total number of parties that includes Trubion, Wyeth
                         and all Third Party licensees under such patent
                         application or patent (e.g., if there are two (2) Third
                         Party licensees in addition to Wyeth and Trubion, then
                         Wyeth shall be responsible for twenty-five

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                         percent (25%)), of Trubion's out-of-pocket expenses
                         incurred in a given country in connection with
                         preparing, filing, prosecuting and maintaining such
                         patent application or patent. (As used in this Article
                         6, "out-of-pocket expenses" shall be deemed to include,
                         without limitation, reasonable attorneys' fees.) Wyeth
                         shall reimburse Trubion on a quarterly basis within ***
                         of receiving an invoice accompanied by supporting
                         documentation demonstrating the out-of-pocket expenses
                         so incurred. On an annual basis, during the last
                         Calendar Quarter of each year, Trubion shall provide
                         Wyeth with a good faith, written estimate of the
                         out-of-pocket expenses reimbursable by Wyeth under this
                         Section 6.2.1(a) that Trubion expects to incur in the
                         following calendar year. In addition, if Trubion elects
                         not to file a patent application on Trubion Know-How
                         that, if filed, would be a Product-Related Patent
                         Right, or to cease the prosecution and/or maintenance
                         of any Product-Related Patent Rights, (except for
                         abandonment of a patent application in favor of a
                         patent application subsequently filed for purposes of
                         continuing the prosecution of Patent Rights claiming
                         the inventions included in the abandoned patent
                         application), Trubion shall provide Wyeth with written
                         notice immediately upon the decision to not file or
                         continue the prosecution of such patent application or
                         maintenance of such patent. In such event, Trubion
                         shall permit Wyeth, at Wyeth's sole discretion, to file
                         and/or continue prosecution and/or maintenance of such
                         Product-Related Patent Right on Trubion's behalf and at
                         Wyeth's own expense. If Wyeth elects to file or to
                         continue such prosecution or maintenance, it shall
                         notify Trubion in writing of such decision within ***
                         of receipt of Trubion's written notice, in which case
                         Trubion shall assign to Wyeth such Product-Related
                         Patent Right abandoned by Trubion and shall execute
                         such documents and perform such acts, at Wyeth's
                         expense, as may be reasonably necessary to permit Wyeth
                         to file, prosecute and/or maintain such Product-Related
                         Patent Right. In the event that Wyeth files or
                         continues the prosecution or maintenance of any such
                         Product-Related Patent Right pursuant to this Section
                         6.2.1(a), then Wyeth

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                         shall no longer be obligated to pay to Trubion any
                         royalty payments that would be due solely with respect
                         to such Product-Related Patent Right.

                    (b)  WYETH PATENT RIGHTS. Subject to Section 6.2.1(d), and
                         except with respect to Covered SMIP Improvements,
                         Wyeth, at its own expense, shall have the sole right,
                         but not the obligation, to prepare, file, prosecute and
                         maintain, throughout the Territory, all Wyeth Patent
                         Rights, using patent counsel of Wyeth's choice.

                    (c)  JOINT PATENT RIGHTS. Subject to Section 6.2.1(d), in
                         the event the Parties make any Joint Invention
                         (excluding a Covered SMIP Improvement), the Joint
                         Patent Committee shall promptly meet to discuss and
                         determine whether to seek patent protection thereon. If
                         the Joint Patent Committee decides to seek patent
                         protection on such Joint Invention, then Wyeth shall
                         have the primary obligation to prepare, file, prosecute
                         and maintain any corresponding Joint Patent Rights
                         throughout the Territory using patent counsel mutually
                         agreeable to the Parties, such agreement not to be
                         unreasonably withheld. Wyeth shall give Trubion a
                         reasonable opportunity to review and comment on the
                         text of any patent application with respect to such
                         Joint Patent Right before filing, shall consult with
                         Trubion with respect thereto, shall reasonably consider
                         and address any of Trubion's comments, and shall supply
                         Trubion with a copy of each such patent application as
                         filed, together with notice of its filing date and
                         serial number. Wyeth shall keep Trubion advised of the
                         status of the actual and prospective patent filings
                         (including, without limitation, the grant of any Joint
                         Patent Rights), shall provide Trubion with a reasonable
                         opportunity to comment on all correspondence received
                         from and all proposed submissions to be made to any
                         government patent office or authority related to the
                         filing, prosecution and maintenance of such patent
                         filings, shall consult with Trubion with respect
                         thereto, and shall reasonably consider and address any
                         of Trubion's comments on such correspondence and
                         submissions. Trubion shall reimburse Wyeth for *** of
                         the out-of-pocket expenses incurred by Wyeth in
                         connection with preparing, filing, prosecuting and
                         maintaining such Joint Patent Rights (other than
                         out-of-pocket expenses for inventorship determinations
                         and inventorship disputes), which reimbursement will be
                         made within *** of receiving invoices, such invoices to
                         be submitted by Wyeth no more often than once per
                         Calendar Quarter and to be

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                         accompanied by supporting documentation demonstrating
                         and detailing the expenses so incurred. On an annual
                         basis, during the last Calendar Quarter of each year,
                         Wyeth shall provide Trubion with a good faith, written
                         estimate of the out-of-pocket expenses reimbursable by
                         Trubion under this Section 6.2.1(c) that Wyeth expects
                         to incur in the following calendar year. If Wyeth
                         elects not to file a patent application on any such
                         Joint Patent Rights, or to cease the prosecution and/or
                         maintenance of any such Joint Patent Rights (except for
                         abandonment of a patent application in favor of a
                         patent application subsequently filed for purposes of
                         continuing the prosecution of Patent Rights claiming
                         the inventions included in the abandoned patent
                         application), Wyeth shall provide Trubion with written
                         notice immediately upon the decision to not file or
                         continue the prosecution of such patent application or
                         maintenance of such patent. In such event, Wyeth shall
                         permit Trubion, at Trubion's sole discretion, to file
                         and/or continue prosecution and/or maintenance of such
                         Joint Patent Rights at Trubion's own expense. If
                         Trubion elects to continue such prosecution or
                         maintenance, it shall notify Wyeth in writing of such
                         decision within *** of receipt of Wyeth's written
                         notice, in which case, Wyeth shall assign to Trubion
                         such Joint Patent Rights abandoned by Wyeth and shall
                         execute such documents and perform such acts, at
                         Trubion's expense, as may be reasonably necessary to
                         permit Trubion to file, prosecute and/or maintain such
                         Joint Patent Rights.

                    (d)  CATEGORY 1 AND CATEGORY 2 COVERED SMIP IMPROVEMENTS.

                         (i)  CATEGORY 1 COVERED SMIP IMPROVEMENTS. In the event
                              that Wyeth makes any Category 1 Covered SMIP
                              Improvement (whether it is an invention solely by
                              Wyeth or a Joint Invention), Trubion shall have
                              the first right and primary obligation to prepare,
                              file, prosecute and maintain any Patent Rights
                              covering such Category 1 Covered SMIP Improvement,
                              using patent counsel mutually agreeable to the
                              Parties, such agreement not to be unreasonably
                              withheld. Trubion shall give Wyeth a reasonable
                              opportunity to review and comment on the text of
                              any patent application with respect to such
                              Category 1 Covered SMIP Improvement before filing,
                              shall consult with Wyeth with respect thereto,
                              shall reasonably consider and address any of
                              Wyeth's comments, and shall supply

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                              Wyeth with a copy of the patent application as
                              filed, together with notice of its filing date and
                              serial number. Trubion shall keep Wyeth advised of
                              the status of the actual and prospective patent
                              filings (including, without limitation, the grant
                              of any Patent Rights covering such Category 1
                              Covered SMIP Improvements), shall provide Wyeth
                              with a reasonable opportunity to comment on all
                              correspondence received from and all proposed
                              submissions to be made to any government patent
                              office or authority related to the filing,
                              prosecution and maintenance of such patent
                              filings, shall consult with Wyeth with respect
                              thereto, and shall reasonably consider and address
                              any of Wyeth's comments on such correspondence and
                              submissions. Each Party shall be responsible for
                              *** of Trubion's out-of-pocket expenses incurred
                              in connection with preparing, filing, prosecuting
                              and maintaining such Category 1 Covered SMIP
                              Improvement-related Patent Rights throughout the
                              Territory, other than out-of-pocket expenses for
                              inventorship determinations and inventorship
                              disputes. Wyeth shall reimburse Trubion on a
                              quarterly basis within *** of receiving an invoice
                              accompanied by supporting documentation
                              demonstrating the out-of-pocket expenses so
                              incurred. On an annual basis, during the last
                              Calendar Quarter of each year, Trubion shall
                              provide Wyeth with a good faith, written estimate
                              of the out-of-pocket expenses reimbursable by
                              Wyeth under this Section 6.2.1(d)(i) that Trubion
                              expects to incur in the following calendar year.
                              In addition, if Trubion elects not to file a
                              patent application on a Category 1 Covered SMIP
                              Improvement, or to cease the prosecution and/or
                              maintenance of any Category 1 Covered SMIP
                              Improvement-related Patent Right (except for
                              abandonment of a patent application in favor of a
                              patent application subsequently filed for purposes
                              of continuing the prosecution of Patent Rights
                              claiming the inventions included in the abandoned
                              patent application), Trubion shall provide Wyeth
                              with written notice immediately upon the decision
                              to not file or continue the prosecution of such
                              patent application or maintenance of such patent.
                              If Wyeth elects to continue such prosecution or
                              maintenance, it shall notify Trubion in writing of
                              such decision within *** of receipt of Trubion's
                              written notice, in which case Trubion shall assign
                              to Wyeth

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                              the right to file, prosecute and maintain such
                              Category 1 Covered SMIP Improvement-related Patent
                              Right, and shall execute such documents and
                              perform such acts, at Wyeth's expense, as may be
                              reasonably necessary to permit Wyeth to file,
                              prosecute and/or maintain such Category 1 Covered
                              SMIP Improvement-related Patent Right. In the
                              event that Wyeth continues the prosecution or
                              maintenance of any Category 1 Covered SMIP
                              Improvement-related Patent Right pursuant to this
                              Section 6.2.1(d)(i), Wyeth shall do so at its own
                              expense, and Wyeth shall no longer be obligated to
                              pay to Trubion any royalty payments that would be
                              due solely with respect to any such Category 1
                              Covered SMIP Improvement-related Patent Right.

                         (ii) CATEGORY 2 COVERED SMIP IMPROVEMENTS. In the event
                              that Wyeth makes any Category 2 Covered SMIP
                              Improvement (whether it is an invention solely by
                              Wyeth or a Joint Invention), Wyeth shall have the
                              first right and primary obligation to prepare,
                              file, prosecute and maintain any Patent Rights
                              covering such Category 2 Covered SMIP Improvement,
                              at its own expense, using patent counsel mutually
                              agreeable to the Parties, such agreement not to be
                              unreasonably withheld. Wyeth shall give Trubion a
                              reasonable opportunity to review and comment on
                              the text of any patent application with respect to
                              such Category 2 Covered SMIP Improvement before
                              filing, shall consult with Trubion with respect
                              thereto, shall reasonably consider and address any
                              of Trubion's comments, and shall supply Trubion
                              with a copy of the patent application as filed,
                              together with notice of its filing date and serial
                              number. Wyeth shall keep Trubion advised of the
                              status of the actual and prospective patent
                              filings (including, without limitation, the grant
                              of any Patent Rights covering such Category 2
                              Covered SMIP Improvement), shall provide Trubion
                              with a reasonable opportunity to comment on all
                              correspondence received from and all proposed
                              submissions to be made to any government patent
                              office or authority related to the filing,
                              prosecution and maintenance of such patent
                              filings, shall consult with Trubion with respect
                              thereto, and shall reasonably consider and address
                              any of Trubion's comments on such correspondence
                              and submissions. If Wyeth elects not to file a
                              patent application on a

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                              Category 2 Covered SMIP Improvement, or to cease
                              the prosecution and/or maintenance of any Category
                              2 Covered SMIP Improvement-related Patent Right
                              (except for abandonment of a patent application in
                              favor of a patent application subsequently filed
                              for purposes of continuing the prosecution of
                              Patent Rights claiming the inventions included in
                              the abandoned patent application), Wyeth shall
                              provide Trubion with written notice immediately
                              upon the decision to not file or continue the
                              prosecution of such patent application or
                              maintenance of such patent. If Trubion elects to
                              continue such prosecution or maintenance, it shall
                              notify Wyeth in writing of such decision within
                              *** of receipt of Wyeth's written notice, in which
                              case Wyeth shall assign to Trubion such Category 2
                              Covered SMIP Improvement-related Patent Right
                              abandoned by Wyeth and shall execute such
                              documents and perform such acts, at Trubion's
                              expense, as may be reasonably necessary to permit
                              Trubion to file, prosecute and/or maintain such
                              Category 2 Covered SMIP Improvement-related Patent
                              Right.

               6.2.2. ENFORCEMENT OF PATENT RIGHTS.

                    (a)  NOTICE. If either Wyeth or Trubion becomes aware of any
                         infringement, anywhere in the Territory, of any issued
                         patent within the Trubion Patent Rights (including
                         Product-Related Patent Rights), Wyeth Patent Rights or
                         Joint Patent Rights, which infringing activity
                         adversely affects or is reasonably expected to
                         adversely affect any SMIP or Licensed Product
                         hereunder, it will promptly notify the other Party in
                         writing to that effect and the Parties will consult
                         with each other through the Joint Patent Committee
                         regarding any actions to be taken with respect to such
                         infringing activity; provided, however, that neither
                         Party is obligated to disclose confidential information
                         of a Third Party (other than a sublicensee under this
                         Agreement, to the extent such Party is permitted to do
                         so under the terms of the sublicense).

                    (b)  PRODUCT-RELATED PATENT RIGHTS. To the extent permitted
                         under the Trubion Third Party Agreements, if
                         applicable, Wyeth shall have the first right, but not
                         the obligation, to take action to obtain a
                         discontinuance of infringement or bring suit against a
                         Third Party infringer of Product-Related Patent Rights
                         under which Wyeth has an exclusive license

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                         to make, use and sell Licensed Products under this
                         Agreement, to the extent such infringement involves a
                         product directed against a Licensed Target. Wyeth shall
                         have such first right within three (3) months from the
                         date of notice and the right to join Trubion as a party
                         plaintiff. Wyeth shall be responsible for, and shall
                         bear, all the out-of-pocket expenses of any suit
                         brought by it claiming infringement of any such
                         Product-Related Patent Rights; provided that Trubion
                         shall reimburse Wyeth for *** of the out-of-pocket
                         expenses incurred in connection therewith. Trubion will
                         cooperate with Wyeth in any such suit and shall have
                         the right to consult with Wyeth and to participate in
                         and be represented by independent counsel in such
                         litigation at its own expense. Wyeth shall incur no
                         liability to Trubion as a consequence of such
                         litigation or any unfavorable decision resulting
                         therefrom, including any decision holding any of the
                         Product-Related Patent Rights invalid or unenforceable.
                         Any recoveries obtained by Wyeth as a result of any
                         proceeding against such Third Party infringer shall be
                         allocated as follows:

                         (i)  Such recovery shall first be used to reimburse
                              each Party for all out-of-pocket litigation
                              expenses in connection with such litigation paid
                              by that Party; and

                         (ii) With respect to any remaining recovery, *** shall
                              go to Wyeth and *** shall go to Trubion.

                         If, after the expiration of the three (3) month period
                         (or, if earlier, the date upon which Wyeth provides
                         written notice that it does not plan to bring suit),
                         Wyeth has not obtained a discontinuance of such
                         infringement of Product-Related Patent Rights or filed
                         suit against any such Third Party infringer hereunder,
                         then Trubion shall have the right, but not the
                         obligation, to bring suit against such Third Party
                         infringer of the Product-Related Patent Rights under
                         which Wyeth has an exclusive license under this
                         Agreement, provided that each Party shall bear *** of
                         the out-of-pocket expenses of such suit. Wyeth will
                         cooperate with Trubion in any such suit for
                         infringement of such Product-Related Patent Rights
                         brought by Trubion against a Third Party, and shall
                         have the right to consult with Trubion and to
                         participate in and be represented by independent
                         counsel in such litigation at its own expense. Trubion
                         shall incur no liability to Wyeth as a consequence of
                         such litigation or any

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                         unfavorable decision resulting therefrom, including any
                         decision holding any of the Product-Related Patent
                         Rights invalid or unenforceable. Any recoveries
                         obtained by Trubion as a result of any such proceeding
                         against a Third Party infringer shall be allocated as
                         follows:

                         (iii) Such recovery shall first be used to reimburse
                              each Party for all out-of-pocket litigation
                              expenses in connection with such litigation paid
                              by that Party; and

                         (iv) With respect to any remaining recovery, *** shall
                              go to Trubion.

                    (c)  JOINT PATENT RIGHTS. With respect to any notice of a
                         Third Party infringer of the Joint Patent Rights, the
                         Joint Patent Committee shall meet as soon as reasonably
                         practicable to discuss such infringement and determine
                         an appropriate course of action. Wyeth shall have the
                         first right but not the obligation to bring an action
                         against such Third Party infringer or otherwise address
                         such alleged infringement within *** from the date of
                         notice and to control such litigation or other means of
                         addressing such infringement. Wyeth shall be
                         responsible for, and shall bear, all the out-of-pocket
                         expenses of any suit brought by it claiming
                         infringement of any such Joint Patent Rights; provided
                         that Trubion shall reimburse Wyeth for *** of the
                         out-of-pocket expenses incurred in connection
                         therewith. Trubion shall cooperate with Wyeth, at
                         Wyeth's expense, in any such suit brought by Wyeth and
                         shall have the right to consult with Wyeth and
                         participate in and be represented by independent
                         counsel in such litigation at its own expense. Wyeth
                         shall incur no liability to Trubion as a consequence of
                         such litigation or any unfavorable decision resulting
                         therefrom, including any decision holding any of the
                         Joint Patent Rights invalid or unenforceable. Any
                         recoveries obtained by Wyeth as a result of any
                         proceeding against such Third Party infringer shall be
                         allocated as follows:

                         (i)  Such recovery shall first be used to reimburse
                              each Party for all out-of-pocket litigation
                              expenses in connection with such litigation paid
                              by that Party; and

                         (ii) With respect to any remaining recovery, *** shall
                              go to Wyeth and *** shall go to Trubion.

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                    If, after the expiration of the three (3) month period (or,
                    if earlier, the date upon which Wyeth provides written
                    notice that it does not plan to bring suit) Wyeth elects not
                    to take action against a Third Party infringer of the Joint
                    Patent Rights and Trubion elects to bring an action, then
                    Wyeth shall cooperate, at Trubion's expense, in such action.
                    Trubion shall incur no liability to Wyeth as a consequence
                    of such litigation or any unfavorable decision resulting
                    therefrom, including any decision holding any of the Joint
                    Patent Rights invalid or unenforceable. Any recoveries
                    obtained by Trubion shall go to Trubion.

          6.2.3. INFRINGEMENT AND THIRD PARTY LICENSES.

               (a)  INFRINGEMENT OF THIRD PARTY PATENTS - COURSE OF ACTION. If
                    the research, Development, Manufacture or Commercialization
                    of any Licensed Product is alleged by a Third Party to
                    infringe a Third Party's patent, the Party becoming aware of
                    such allegation shall promptly notify the other Party.

                    Additionally, if either Party determines (with consultation
                    by the Joint Patent Committee) that, based upon the review
                    of a Third Party's patent or patent application or other
                    intellectual property rights, it may be desirable to obtain
                    a license from such Third Party with respect thereto, such
                    Party shall promptly notify the other Party of such
                    determination. In the event Wyeth determines, after good
                    faith consultation with Trubion through the Joint Patent
                    Committee, that it is necessary or useful to obtain licenses
                    under intellectual property rights from Third Parties
                    ("Additional Third Party Licenses") in order to Develop,
                    Manufacture or Commercialize Licensed Products under this
                    Agreement, Wyeth shall be solely responsible for negotiating
                    and obtaining any such Additional Third Party Licenses, but
                    shall not be obligated to do so. Trubion may elect, in its
                    sole discretion, to obtain one or more Third Party licenses
                    that are applicable to Trubion Technology in general but are
                    not Licensed Product-specific ("Trubion Additional Third
                    Party Licenses"); if Trubion so elects, then Trubion shall
                    be solely responsible for negotiating and obtaining any such
                    licenses, but shall not be obligated to do so.

               (b)  THIRD PARTY INFRINGEMENT SUIT. If a Third Party sues a Party
                    (the "Sued Party") alleging that the Sued Party or its
                    Affiliates' or sublicensees' research, Development,

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                    Manufacture or Commercialization of any Licensed Product
                    during the term of and pursuant to this Agreement infringes
                    or will infringe said Third Party's patent, then, upon the
                    Sued Party's request and in connection with the Sued Party's
                    defense of any such Third Party infringement suit, the other
                    Party shall provide reasonable assistance to the Sued Party
                    for such defense. If both Wyeth and Trubion are sued by a
                    Third Party, then the Parties shall consult with one another
                    through the Joint Patent Committee. Unless otherwise
                    determined by the Joint Patent Committee, Wyeth will control
                    the defense of any suit relating to Licensed Products
                    (whether one or both Parties are Sued Parties) and shall
                    select counsel for such suit after consultation through the
                    Joint Patent Committee. Trubion shall have the right to
                    participate in and be represented by independent counsel in
                    such litigation at its own expense. If the alleged
                    infringement is of claims related to the Trubion Technology
                    utilized by Wyeth hereunder, Wyeth shall be responsible for,
                    and shall bear, all the out-of-pocket expenses of such
                    actions; provided that Trubion shall reimburse Wyeth for ***
                    of the out-of-pocket expenses incurred in connection
                    therewith. In the event Trubion is the Party paying such
                    expenses, Trubion shall periodically, but no more than once
                    per Calendar Quarter, invoice Wyeth for its *** share of
                    expenses incurred. All invoices shall be accompanied by
                    supporting documentation reasonably showing the expenses so
                    incurred. Such invoices shall be paid within *** of receipt.
                    In the event Wyeth is the Party paying such expenses, Wyeth
                    shall receive a credit in the amount of Trubion's share of
                    such expenses, which credit shall be applied to royalties
                    due to Trubion under Section 5.4, as adjusted under Section
                    5.4.6; provided that, no such royalty payment to Trubion
                    shall be reduced by more than *** in any Calendar Quarter as
                    a result of such credit. Any portion of the credit not
                    utilized due to the limitations of the preceding sentence
                    shall be carried over and credited to future royalty
                    payments.

               (c)  INTERFERENCE, OPPOSITION, REVOCATION, AND DECLARATORY
                    JUDGMENT ACTIONS. If the Parties, through the Joint Patent
                    Committee, mutually determine that, based upon the review of
                    a Third Party's patent or patent application or other
                    intellectual property rights, it may be desirable to provoke
                    or institute an interference, opposition, revocation or
                    declaratory judgment action with respect thereto, then the
                    Parties shall consult with one another and shall reasonably

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                    cooperate in connection with such an action. Unless
                    otherwise determined by the Joint Patent Committee, Wyeth
                    will control such action and shall select counsel for such
                    action. Wyeth shall be responsible for, and shall bear, all
                    the out-of-pocket expenses of such action; provided that
                    Trubion shall reimburse Wyeth for *** of the out-of-pocket
                    expenses incurred in connection therewith. Wyeth shall
                    submit invoices to Trubion for such expenses, such invoices
                    to be accompanied by supporting documentation reasonably
                    showing the expenses so incurred. Trubion shall have the
                    right to participate in and be represented by independent
                    counsel in such action at its own expense.

          6.2.4. PATENT CERTIFICATIONS. Each Party shall immediately give
               written notice to the other of any certification of which it
               becomes aware filed pursuant to 21 U.S.C. Section 355(b)(2)(A) or
               Section 355(j)(2)(A)(vii) (or any amendment or successor statute
               thereto), any similar statutory or regulatory requirement enacted
               in the future regarding biologic products, or any similar
               statutory or regulatory requirement in any non-U.S. country in
               the Territory claiming that a Joint Patent Right, Wyeth Patent
               Right or a Trubion Patent Right covering a Licensed Product is
               invalid or that infringement will not arise from the Manufacture,
               use or sale of a product by a Third Party. Upon the giving or
               receipt of such notice, Wyeth shall have the first right, but not
               the obligation, to bring an infringement action against such
               Third Party. In such a case, Wyeth shall notify Trubion at least
               ten (10) days prior to the date set forth by statute or
               regulation of its intent to exercise, or not exercise, this
               right. Any infringement action against a Third Party arising
               under this Section 6.2.4 shall be governed by the provisions of
               Section 6.2.2(b) hereof.

          6.2.5. PATENT TERM RESTORATION. The Parties hereto shall cooperate
               with each other in obtaining patent term restoration, or its
               equivalent anywhere in the Territory, including under 35 U.S.C.
               Section 156 and its foreign counterparts, where applicable to the
               Trubion Patent Rights, Wyeth Patent Rights and Joint Patent
               Rights. If elections with respect to obtaining such patent term
               restoration are to be made, Wyeth shall make such election (after
               consultation with Trubion through the Joint Patent Committee) and
               Trubion shall abide by such election.

     6.3. TRADEMARKS. Wyeth shall, in its sole discretion select and own all
          Licensed Product-related Trademarks, trade dress, logos and copyrights
          and names to be used in connection with the Commercialization of any
          Licensed Product hereunder. Trubion shall neither use nor seek to
          register, anywhere in the Territory, any trademarks which are
          confusingly similar to

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          any Trademark or any other trademarks, trade names, trade dress or
          logos used by or on behalf of Wyeth or its sublicensees in connection
          with any Licensed Product; provided, however, that nothing in this
          Section 6.3 shall be construed to prevent Trubion from enforcing its
          own trademark, trade name, trade dress or logo rights or affect the
          Parties' obligations under Section 4.13.

7.   CONFIDENTIALITY.

     7.1. CONFIDENTIALITY. Except to the extent expressly authorized by this
          Agreement or otherwise agreed in writing, the Parties agree that, for
          the term of this Agreement and for *** thereafter, each Party (the
          "Receiving Party"), receiving any Confidential Information of the
          other Party (the "Disclosing Party") hereunder shall keep such
          Confidential Information confidential and shall not publish or
          otherwise disclose or use such Confidential Information for any
          purpose other than as provided for in this Agreement except for
          Confidential Information that the Receiving Party can establish:

               (a)  was already known by the Receiving Party (other than under
                    an obligation of confidentiality), at the time of disclosure
                    by the Disclosing Party and such Receiving Party has
                    documentary evidence to that effect;

               (b)  was generally available to the public or otherwise part of
                    the public domain at the time of its disclosure to the
                    Receiving Party;

               (c)  became generally available to the public or otherwise part
                    of the public domain after its disclosure or development, as
                    the case may be, and other than through any act or omission
                    of a Party in breach of this confidentiality obligation;

               (d)  was disclosed to that Party, other than under an obligation
                    of confidentiality, by a Third Party who had no obligation
                    to the Disclosing Party not to disclose such information to
                    others; or

               (e)  was independently discovered or developed by or on behalf of
                    the Receiving Party without the use of the Confidential
                    Information belonging to the other Party and the Receiving
                    Party has documentary evidence to that effect.

     7.2. AUTHORIZED DISCLOSURE AND USE.

          7.2.1. DISCLOSURE. Notwithstanding the foregoing Section 7.1, each
               Party may disclose Confidential Information belonging to the

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               other Party to the extent such disclosure is reasonably necessary
               to:

               (a)  file or prosecute patent applications covering Trubion
                    Know-How, Wyeth Know-How or Joint Know-How as contemplated
                    by this Agreement, in a manner consistent with decisions and
                    recommendations of the Joint Patent Committee under Article
                    6, if the affected Party consents to such disclosure (such
                    consent not to be unreasonably withheld or delayed);
                    provided that a disclosure of a Party's Confidential
                    Information under this Section 7.2.1(a) shall be treated as
                    a publication under Section 7.4.3, and shall be subject to
                    the requirements of advance notice, review period and
                    opportunity to file patent application(s), as set forth in
                    Section 7.4.3,

               (b)  prosecute or defend litigation,

               (c)  exercise rights hereunder provided such disclosure is
                    covered by terms of confidentiality similar to those set
                    forth herein,

               (d)  facilitate discussions with prospective investors (other
                    than pharmaceutical or biotechnology companies) in
                    connection with financing arrangements (not involving any
                    license, collaboration or other arrangement relating to such
                    Party's technology or products) or a proposed acquisition of
                    such Party, subject to appropriate confidentiality
                    agreements and limiting such disclosure to disclosure of the
                    terms and conditions of this Agreement and Know-How to the
                    extent contained in such Party's patent applications; and

               (e)  comply with applicable governmental laws and regulations.

               In the event that a Party shall reasonably deem it necessary to
               disclose, pursuant to this Section 7.2.1, Confidential
               Information belonging to the other Party, the Disclosing Party
               shall to the extent possible give reasonable advance notice of
               such disclosure to the other Party and take reasonable measures
               to ensure confidential treatment of such information.

          7.2.2. USE. Notwithstanding the foregoing Section 7.1, each Party
               shall have the right to use Confidential Information of the other
               Party in carrying out its responsibilities under this Agreement
               in the research, Development, Manufacture and Commercialization
               of Licensed Products.

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     7.3. SEC FILINGS. Either Party may disclose the terms of this Agreement to
          the extent required, in the reasonable opinion of such Party's legal
          counsel, to comply with applicable laws, including, without
          limitation, the rules and regulations promulgated by the United States
          Securities and Exchange Commission. Notwithstanding the foregoing,
          before disclosing this Agreement or any of the terms hereof pursuant
          to this Section 7.3, the Parties will reasonably consult with one
          another on the terms of this Agreement to be redacted in making any
          such disclosure. If a Party discloses this Agreement or any of the
          terms hereof in accordance with this Section 7.3, such Party agrees,
          at its own expense, to seek confidential treatment of portions of this
          Agreement or such terms, as may be reasonably requested by the other
          Party.

     7.4. PUBLIC ANNOUNCEMENTS; PUBLICATIONS.

          7.4.1. COORDINATION. The Parties agree on the importance of
               coordinating their public announcements respecting this Agreement
               and the subject matter thereof (other than academic, scientific
               or medical publications that are subject to the publication
               provision set forth below). Trubion and Wyeth shall, from time to
               time, and at the request of the other Party, discuss and agree on
               the general information content relating to this Agreement
               (including relating to the Research Program and Development
               Program, and/or to research, Development, Manufacture and/or
               Commercialization of Licensed Products) which may be publicly
               disclosed (including, without limitation, by means of any printed
               publication or oral presentation).

          7.4.2. ANNOUNCEMENTS. Except as may be expressly permitted under
               Section 7.3 or Section 7.4.3 or as may be appropriate for Wyeth
               to make in connection with its Commercialization activities as
               contemplated hereunder, subject to Sections 7.1 and 7.2 hereof,
               neither Party will make any public announcement regarding this
               Agreement, the Research Program or the Development Program,
               and/or the research, Development, Manufacturing or
               Commercialization of Licensed Products without the prior written
               approval of the other Party.

          7.4.3. PUBLICATIONS. During the term of this Agreement, each Party
               will submit to the other Party for review and approval all
               proposed academic, scientific and medical publications and public
               presentations relating to the Research Program, the Development
               Program and/or to the research, Development, Manufacture and/or
               Commercialization of any Licensed Product, or any proposed
               disclosure under Section 7.2.1(a), for review in connection with
               preservation of Patent Rights and/or to determine whether any of
               such other Party's Confidential

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               Information should be modified or deleted. Written copies of such
               proposed publications and presentations shall be submitted to the
               non-publishing Party no later than thirty (30) days before
               submission for publication or presentation and the non-publishing
               Party shall provide its comments with respect to such
               publications and presentations within fifteen (15) business days
               of its receipt of such written copy. The review period may be
               extended for an additional thirty (30) days in the event the
               non-publishing Party can demonstrate reasonable need for such
               extension, including, but not limited to, the preparation and
               filing of patent applications. By mutual agreement, this period
               may be further extended. Wyeth and Trubion will each comply with
               standard academic practice regarding authorship of scientific
               publications and recognition of contribution of other parties in
               any publications relating to the Research Program, the
               Development Program and/or to the research, Development,
               Manufacture and/or Commercialization of any Licensed Product.

8.   REPRESENTATIONS AND WARRANTIES.

     8.1. REPRESENTATIONS AND WARRANTIES OF EACH PARTY. Each of Trubion and
          Wyeth hereby represents and warrants to the other Party hereto as
          follows:

               (a)  it is a corporation or entity duly organized and validly
                    existing under the laws of the state or other jurisdiction
                    of its incorporation or formation;

               (b)  the execution, delivery and performance of this Agreement by
                    such Party has been duly authorized by all requisite
                    corporate action and does not require any shareholder action
                    or approval;

               (c)  it has the power and authority to execute and deliver this
                    Agreement and to perform its obligations and to grant the
                    licenses granted by it to the other Party pursuant to this
                    Agreement;

               (d)  the execution, delivery and performance by such Party of
                    this Agreement and its compliance with the terms and
                    provisions hereof does not and will not conflict with or
                    result in a breach of any of the terms and provisions of or
                    constitute a default under (i) any agreement or instrument
                    binding or affecting it or the subject matter of this
                    Agreement; (ii) the provisions of its charter or operative
                    documents or bylaws; or (iii) any order, writ, injunction or
                    decree of any court or governmental authority entered

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                    against it or by which any of its property is bound, except
                    where such conflict, breach or default would not materially
                    impact (A) the Party's ability to meet its obligations
                    hereunder or (B) the rights granted to the other Party
                    hereunder; and

               (e)  it has not granted to any Third Party any right or license
                    which would conflict in any material respect with the rights
                    granted by it to the other Party hereunder.

8.2. ADDITIONAL REPRESENTATIONS AND WARRANTIES OF TRUBION. In addition to the
     representations and warranties made by Trubion in Section 8.1, Trubion,
     subject to Section 8.7, hereby represents and warrants to Wyeth that as of
     the Signing Date:

               (a)  except as disclosed in Exhibit 8.2(d) attached hereto,
                    Trubion is the sole and exclusive owner of the Trubion
                    Patent Rights and Trubion has not placed, or suffered to be
                    placed, any liens, charges or encumbrances on or against the
                    Trubion Patent Rights;

               (b)  Exhibit 1.129 is a true and complete list of Trubion Patent
                    Rights that pertain to Licensed Products, provided that an
                    inadvertent omission from such list may be cured by amending
                    Exhibit 1.129;

               (c)  the Trubion Patent Rights are existing and, to Trubion's
                    knowledge, no issued or granted patents within the Trubion
                    Patent Rights are invalid or unenforceable;

               (d)  ***;

               (e)  except as set forth in Exhibit 8.2(e) attached hereto, no
                    Trubion Patent Right listed in Exhibit 1.129 attached hereto
                    is subject to any funding agreement with any government or
                    government agency;

               (f)  Trubion has received no written notice alleging infringement
                    of a Third Party Patent Right in connection with its
                    research and Development of SMIPs directed against a Trubion
                    Target, and Trubion has disclosed to Wyeth all material
                    information of which Trubion is aware as to whether the
                    research, Development, Manufacture, use or sale of SMIPs
                    directed against a Trubion Target, in the form that is the
                    subject of the clinical studies ongoing as of the Signing
                    Date, if such SMIPs were researched, Developed,
                    Manufactured, used or sold as of the Signing

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                    Date, infringes or would infringe issued or granted patents
                    owned by a Third Party as of the Signing Date;

               (g)  the Trubion Patent Rights are not subject to any litigation,
                    judgments or settlements against or owed by Trubion, nor has
                    Trubion received written notice of any threats of such
                    litigation;

               (h)  Trubion is in compliance in all material respects with all
                    agreements with Third Parties relating to Licensed Products
                    that are sublicensed to Wyeth hereunder;

               (i)  ***

               (j)  the Trubion Patent Rights are not the subject of any
                    interference, opposition, reissue or reexamination
                    proceeding in the United States or, to the knowledge of
                    Trubion, any opposition proceeding outside of the United
                    States.

     8.3. MUTUAL COVENANT. Each Party covenants to the other Party that it shall
          at all times comply with all applicable material laws and regulations
          relating to its activities under this Agreement.

     8.4. ADDITIONAL COVENANTS OF TRUBION. During the term of this Agreement,
          Trubion will use diligent efforts not to materially breach any
          agreement between Trubion and a Third Party that provides Trubion
          Patent Rights pertaining to the research, Development, Manufacture or
          Commercialization of any Licensed Product, and it will provide Wyeth
          promptly with notice of any such alleged breach. ***. During the term
          of this Agreement, Trubion will not knowingly use any Know-How
          misappropriated from a Third Party in connection with any Licensed
          Product being provided for Commercialization under this Agreement.

     8.5. REPRESENTATION BY LEGAL COUNSEL. Each Party hereto represents that it
          has been represented by legal counsel in connection with this
          Agreement and acknowledges that it has participated in the drafting
          hereof. In interpreting and applying the terms and provisions of this
          Agreement, the Parties agree that no presumption shall exist or be
          implied against the Party which drafted such terms and provisions.

     8.6. NO INCONSISTENT AGREEMENTS. Neither Party has in effect and after the
          Signing Date neither Party shall enter into any oral or written
          agreement or arrangement that would be inconsistent with its
          obligations under this Agreement.

     8.7. DISCLAIMER. EXCEPT AS OTHERWISE EXPRESSLY SET FORTH IN SECTIONS 8.1,
          8.2 AND 8.5, THE PARTIES MAKE NO

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          REPRESENTATIONS AND EXTEND NO WARRANTIES OF ANY KIND, EITHER EXPRESS
          OR IMPLIED, AND PARTICULARLY THAT LICENSED PRODUCTS WILL BE
          SUCCESSFULLY DEVELOPED HEREUNDER, AND IF LICENSED PRODUCTS ARE
          DEVELOPED, WITH RESPECT TO SUCH LICENSED PRODUCTS, THE PARTIES
          DISCLAIM ALL IMPLIED WARRANTIES OF TITLE, NON-INFRINGEMENT,
          MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

9.   GOVERNMENT APPROVALS; TERM AND TERMINATION.

     9.1. HSR FILING. Each Party shall be responsible for its own costs,
          expenses, and filing fees associated with any HSR Filing; provided,
          however, that Wyeth shall be solely responsible for any fees (other
          than penalties that may be incurred as a result of actions or
          omissions on the part of Trubion) required to be paid to any
          government agency in connection with making any such HSR Filing.

     9.2. OTHER GOVERNMENT APPROVALS. Trubion and Wyeth will cooperate and use
          respectively all reasonable efforts to make all registrations, filings
          and applications, to give all notices and to obtain as soon as
          practicable all governmental or other consents, transfers, approvals,
          orders, qualifications authorizations, permits and waivers, if any,
          and to do all other things necessary or desirable for the consummation
          of the transactions as contemplated hereby.

     9.3. TERM. The term of this Agreement will commence on the Signing Date and
          shall extend, unless this Agreement is terminated earlier in
          accordance with this Article 9, on a Licensed Product by Licensed
          Product and country by country basis until such time as the Royalty
          Period with respect to the sale of such Licensed Product in such
          country expires.

     9.4. TERMINATION UPON HSR DENIAL. This Agreement shall terminate (a) at
          Wyeth's option, immediately upon written notice to Trubion, in the
          event that the United States Federal Trade Commission and/or the
          United States Department of Justice shall seek a preliminary
          injunction under the HSR Act against Trubion and Wyeth to enjoin the
          transactions contemplated by this Agreement, (b) at the election of
          either Party, immediately upon written notice to the other Party, in
          the event that the United States Federal Trade Commission and/or the
          United States Department of Justice shall obtain a preliminary
          injunction under the HSR Act against Trubion and Wyeth to enjoin the
          transactions contemplated by this Agreement, or (c) at the election of
          either Party, immediately upon written notice to the other Party, in
          the event that the HSR Clearance Date shall not have occurred on or
          prior to *** after the effective date of the HSR Filing.

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     9.5. MATERIAL BREACH. In the event that either Party commits a material
          breach of its representations, warranties or obligations under this
          Agreement, the other Party may terminate this Agreement (a) on a
          Licensed Target by Licensed Target and country by country basis, to
          the extent that such material breach relates to Licensed Product(s)
          directed against such Licensed Target(s) in such country(ies) or (b)
          in its entirety only if such material breach fundamentally frustrates
          the objectives or transactions contemplated by this Agreement taken as
          a whole. If a Party elects to exercise such right to terminate, it
          shall do so by providing written notice of the alleged breach (the
          "Notice of Breach") to the breaching Party. If such material breach
          pertains to the payment of undisputed amounts payable under this
          Agreement and remains uncured for *** after the breaching Party's
          receipt of such Notice of Breach or, if such material breach pertains
          to another material breach (other than for non-payment) and remains
          uncured for *** after the breaching Party's receipt of such Notice of
          Breach, then the non-breaching Party may terminate this Agreement, as
          and to the extent permitted in (a) or (b) above, on *** notice by
          giving a written notice of termination ("Notice of Termination") to
          the breaching Party; provided, however, that if such breach (other
          than for non-payment) is not susceptible to cure within the initial
          *** period and the breaching Party uses continuous, diligent, good
          faith efforts to cure such breach, it shall document such efforts by
          written notice to the non-breaching Party on or before the end of such
          *** period, and the stated cure period will be extended by an
          additional ***. This Agreement shall be deemed terminated (as and to
          the extent permitted in (a) or (b) above) *** after the breaching
          Party's receipt of such Notice of Termination, unless the breaching
          Party has fully cured the breach prior to the expiration of such ***
          period.

          In the event that Trubion is the breaching Party and fails to cure any
          such material breach within the applicable time period(s) set forth
          above, Wyeth, within *** after the expiration of the cure period for
          such breach, may elect, in lieu of terminating this Agreement, by
          written notice to Trubion (a "Notice of Modification"), to modify the
          terms of this Agreement, as (and only to the extent) provided in
          Section 9.8, on a Licensed Target-by-Licensed Target and
          country-by-country basis (but only to the extent such material breach
          relates to Licensed Product(s) directed against such Licensed
          Target(s) in such country(ies)), in which event, Wyeth shall be deemed
          to have waived its right to terminate this Agreement under this
          Section 9.5 with respect to such Licensed Target(s) in such
          country(ies) only with respect to the material breach giving rise to
          such action under this Section 9.5. Notwithstanding the foregoing, a
          Party shall not be in breach of its obligations under this Agreement
          to the extent that such breach was caused by the other Party's failure
          to perform its obligations hereunder.

     9.6. TERMINATION BY WYETH.

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          9.6.1. TERMINATION WITHOUT CAUSE. Commencing on the second anniversary
               of the Effective Date, Wyeth shall have the right, exercisable
               upon ninety (90) days prior written notice to Trubion, to
               terminate this Agreement either (a) in its entirety, or (b) on a
               Licensed Target by Licensed Target and country by country basis.
               Wyeth's rights under this Section 9.6.1 are separate from and in
               addition to its rights to terminate the Research Program under
               Section 3.3.2 hereof.

          9.6.2. TERMINATION FOR A MATERIAL SAFETY OR REGULATORY ISSUE. Wyeth
               shall have the right to terminate this Agreement, at any time, on
               a Licensed Target by Licensed Target basis, by giving *** prior
               written notice to Trubion in the event of any safety or
               regulatory issue that would have a material adverse effect on
               Wyeth's ability to research, Develop, Manufacture or
               Commercialize any Licensed Product directed against such Licensed
               Target, as determined in Wyeth's reasonable judgment and
               according to Wyeth's standard internal procedures for evaluating
               such safety or regulatory issues. Effects of such termination
               shall be as set forth in Section ***.

     9.7. EFFECTS OF TERMINATION.

          9.7.1. EFFECT OF TERMINATION BY WYETH FOR CAUSE.

               (a)  Without limiting any other legal or equitable remedies that
                    Wyeth or Trubion may have, subject to Section 11.3, if this
                    Agreement is terminated in its entirety by Wyeth for cause
                    under Section 9.5, the following provisions shall apply:

                    (i)  all licenses granted by each Party to the other Party
                         under this Agreement shall terminate (except as
                         provided in Section 9.7.10 below);

                    (ii) during the *** period after the effective date of such
                         termination, Trubion shall have the right to negotiate
                         with Wyeth an agreement which grants to Trubion a
                         non-exclusive license (with the right to grant
                         sublicenses) to practice, use and exploit the Wyeth
                         Applied Technology with respect to the research,
                         Development, Manufacture and Commercialization of
                         Licensed Products on commercially reasonable terms. If
                         Trubion exercises such right, Wyeth shall negotiate the
                         terms of such license with Trubion diligently and in
                         good faith; provided that, if Trubion and Wyeth
                         negotiate, but do not enter into, such non-exclusive
                         license, Wyeth shall not enter into any agreement

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                         granting a license to a Third Party under the Wyeth
                         Applied Technology within *** after the end of such
                         negotiations on terms more favorable to such Third
                         Party than those last offered by Wyeth to Trubion,
                         without first offering Trubion, for a period of not
                         less than ***, the opportunity to review such terms
                         after full disclosure thereof and enter into a
                         non-exclusive license on such more favorable terms,
                         and, if Trubion accepts such more favorable terms, the
                         Parties shall promptly negotiate definitive agreements
                         relating thereto;

                    (iii) during the *** period after the effective date of such
                         termination, Trubion shall have the right to negotiate
                         with Wyeth for the transfer of Product Data and Filings
                         to Trubion, and for the grant by Wyeth to Trubion of
                         the right and license to use the Licensed
                         Product-specific Trademarks and Product-specific names
                         pertaining to the Licensed Product(s) as existing at
                         the time of termination (collectively, "Existing
                         Trademarks"), on commercially reasonable terms. If
                         Trubion exercises such right, Wyeth shall negotiate the
                         terms of such transfer and license with Trubion
                         diligently and in good faith; provided that, if Trubion
                         and Wyeth negotiate but do not enter into such an
                         agreement, Wyeth shall not enter into any agreement
                         granting such rights to a Third Party within *** after
                         the end of such negotiation on terms more favorable to
                         such Third Party than those last offered by Wyeth to
                         Trubion, without first offering Trubion, for a period
                         of not less than ***, the opportunity to review such
                         terms after full disclosure thereof and enter into such
                         an agreement on such more favorable terms, and, if
                         Trubion accepts such more favorable terms, the Parties
                         shall promptly negotiate definitive agreements relating
                         thereto; and

                    (iv) subject to the provisions of Section 9.9, this
                         Agreement shall be of no further force or effect.

               (b)  Without limiting any other legal or equitable remedies that
                    Wyeth or Trubion may have, subject to Section 11.3, if this
                    Agreement is terminated by Wyeth for cause under Section 9.5
                    with respect to a Licensed Target in all countries, but not
                    in its entirety, the following provisions shall apply:

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                    (i)  if such Licensed Target is a Trubion Target, all of the
                         Parties' rights and obligations under Article 3 in
                         connection with the Research Program shall cease in
                         their entirety; provided that all amounts due for
                         research performed and costs incurred prior to the date
                         of such termination shall remain payable in accordance
                         with the provisions of Article 3;

                    (ii) if such Licensed Target is a Wyeth Target, all of the
                         Parties' rights and obligations under Article 3 in
                         connection with the Research Program shall continue,
                         subject to Wyeth's option, exercisable in its sole
                         discretion, to terminate the Research Program as
                         follows: Wyeth shall exercise such option to terminate
                         the Research Program (if it so elects) by a written
                         statement to that effect included in Wyeth's Notice of
                         Termination (described in Section 9.5 above). If Wyeth
                         exercises such option to terminate the Research
                         Program, all of the Parties' rights and obligations
                         under Article 3 in connection with the Research Program
                         shall cease in their entirety *** after Trubion's
                         receipt of such Notice of Termination; provided that
                         all amounts due for research performed and costs
                         incurred prior to the date of such termination shall
                         remain payable in accordance with the provisions of
                         Article 3;

                    (iii) if such terminated Licensed Target is the CD20
                         Antigen, Wyeth shall have no further obligation to
                         reimburse Trubion under Section 4.6 with respect to
                         expenses incurred after the effective date of
                         termination;

                    (iv) all licenses granted by each Party to the other Party
                         under this Agreement with respect to Licensed Products
                         directed against such Licensed Target shall terminate
                         (except as provided in Section 9.7.10 below);

                    (v)  the provisions of Section 9.7.1(a)(ii), with such
                         changes as are appropriate in the context of such
                         limited termination, shall apply with respect to the
                         Licensed Products directed against such Licensed
                         Target; and

                    (vi) the provisions of Section 9.7.1(a)(iii), with such
                         changes as are appropriate in the context of such

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                         limited termination, shall apply with respect to
                         Product Data and Filings, and Existing Trademarks,
                         relating to the Licensed Products directed against such
                         Licensed Target.

               (c)  Without limiting any other legal or equitable remedies that
                    Wyeth or Trubion may have, subject to Section 11.3, if this
                    Agreement is terminated by Wyeth for cause under Section 9.5
                    with respect to all Licensed Targets in a country, but not
                    in its entirety, the following provisions shall apply:

                    (i)  if such country is a Major Market Country, all of the
                         Parties' rights and obligations under Article 3 in
                         connection with the Research Program shall cease in
                         their entirety; provided that all amounts due for
                         research performed and costs incurred prior to the date
                         of such termination shall remain payable in accordance
                         with the provisions of Article 3;

                    (ii) if such country is not a Major Market Country, all of
                         the Parties' rights and obligations under Article 3 in
                         connection with the Research Program shall continue,
                         subject to Wyeth's option, exercisable in its sole
                         discretion, to terminate the Research Program as
                         follows: Wyeth shall exercise such option to terminate
                         the Research Program (if it so elects) by a written
                         statement to that effect included in Wyeth's Notice of
                         Termination (described in Section 9.5 above). If Wyeth
                         exercises such option to terminate the Research
                         Program, all of the Parties' rights and obligations
                         under Article 3 in connection with the Research Program
                         shall cease in their entirety *** after Trubion's
                         receipt of such Notice of Termination; provided that
                         all amounts due for research performed and costs
                         incurred prior to the date of such termination shall
                         remain payable in accordance with the provisions of
                         Article 3;

                    (iii) all licenses granted by each Party to the other Party
                         under this Agreement with respect to such country shall
                         terminate (except as provided in Section 9.7.10 below);
                         and

                    (iv) the term "Territory" as used in this Agreement shall
                         thereafter exclude such country;

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                    (v)  except as provided in Section 9.9, neither Wyeth nor
                         Trubion shall have any further obligations under this
                         Agreement with respect to such country;

                    (vi) the provisions of Section 9.7.1(a)(ii), with such
                         changes as are appropriate in the context of such
                         limited termination, shall apply with respect to
                         Licensed Products in such country; and

                    (vii) the provisions of Section 9.7.1(a)(iii), with such
                         changes as are appropriate in the context of such
                         limited termination, shall apply with respect to
                         Product Data and Filings, and Existing Trademarks,
                         relating to Licensed Products in such country.

          9.7.2. EFFECT OF TERMINATION BY TRUBION FOR CAUSE.

               (a)  Without limiting any other legal or equitable remedies that
                    Trubion or Wyeth may have, subject to Section 11.3, if this
                    Agreement is terminated in its entirety by Trubion for cause
                    under Section 9.5, the following provisions shall apply:

                    (i)  all licenses granted by each Party to the other Party
                         under this Agreement shall terminate (except as
                         provided in Section 9.7.10 below);

                    (ii) Wyeth and Trubion shall, upon Trubion's request, such
                         request made within ninety (90) days after such
                         termination, enter into negotiations of a non-exclusive
                         license from Wyeth to Trubion under which Wyeth will
                         grant to Trubion a non-exclusive license (with the
                         right to grant sublicenses) to practice, use and
                         exploit the Wyeth Applied Technology with respect to
                         the research, Development, Manufacture and
                         Commercialization of Licensed Products as constituted
                         at the time of termination of this Agreement. The
                         Parties hereby agree that such license shall include,
                         inter alia, provisions whereby Trubion shall agree (A)
                         to comply with the applicable requirements of any Third
                         Party license to which the use or exploitation of such
                         Wyeth Applied Technology is subject including, but not
                         limited to the payment of royalties; (B) with respect
                         to any CD20 Products ***, to pay to Wyeth (I) if such
                         termination occurs prior to BLA filing in a Major
                         Market Country, royalties and Additional Research and
                         Development Expense Payments in

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                         amounts equal to *** of those amounts Wyeth would have
                         been obligated to pay Trubion had this Agreement
                         remained in full force and effect or (II) if such
                         termination occurs after BLA filing in a Major Market
                         Country, royalties and Additional Research and
                         Development Expense Payments in amounts equal to *** of
                         those amounts Wyeth would have been obligated to pay
                         Trubion had this Agreement remained in full force and
                         effect; (C) with respect to any Licensed Products other
                         than CD20 Products ***; to pay to Wyeth royalties and
                         other non-royalty payments on commercially reasonable
                         terms; (D) that Trubion shall have no other financial
                         obligations to Wyeth;

                    (iii) the provisions of Section 9.7.7 (Post-Termination
                         Transfer of Product Data and Filings and Existing
                         Trademarks) shall apply;

                    (iv) the provisions of Section 9.7.8 (Manufacturing of
                         Licensed Products After Termination) shall apply; and

                    (v)  subject to the provisions of Section 9.9, this
                         Agreement shall be of no further force or effect.

               (b)  Without limiting any other legal or equitable remedies that
                    Trubion or Wyeth may have, subject to Section 11.3, if this
                    Agreement is terminated by Trubion for cause under Section
                    9.5 with respect to a Licensed Target in all countries, but
                    not in its entirety, the following provisions shall apply:

                    (i)  all of the Parties' rights and obligations under
                         Article 3 in connection with the Research Program shall
                         cease in their entirety; provided that all amounts due
                         for research performed and costs incurred prior to the
                         date of such termination shall remain payable in
                         accordance with the provisions of Article 3;

                    (ii) if such terminated Licensed Target is the CD20 Antigen,
                         Wyeth shall have no further obligation to reimburse
                         Trubion under Section 4.6 with respect to expenses
                         incurred after the effective date of termination;

                    (iii) all licenses granted by each Party to the other Party
                         under this Agreement with respect to Licensed Products
                         directed against such Licensed Target shall

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                         terminate (except as provided in Section 9.7.10 below);

                    (iv) the provisions of Section 9.7.2(a)(ii) (Wyeth's grant
                         of a non-exclusive license to Trubion under Wyeth
                         Applied Technology), with such changes as are
                         appropriate in the context of such limited termination,
                         shall apply to Licensed Products directed against such
                         Licensed Target;

                    (v)  the provisions of Section 9.7.7 (Post-Termination
                         Transfer of Product Data and Filings and Existing
                         Trademarks), with such changes as are appropriate in
                         the context of such limited termination, shall apply
                         with respect to Product Data and Filings, and Existing
                         Trademarks, related to Licensed Products directed
                         against such Licensed Target; and

                    (vi) the provisions of Section 9.7.8 (Manufacturing of
                         Licensed Products After Termination), with such changes
                         as are appropriate in the context of such limited
                         termination, shall apply with respect to Licensed
                         Products directed against such Licensed Target.

               (c)  Without limiting any other legal or equitable remedies that
                    Trubion or Wyeth may have, subject to Section 11.3, if this
                    Agreement is terminated by Trubion for cause under Section
                    9.5 with respect to all Licensed Targets in a country, but
                    not in its entirety, the following provisions shall apply:

                    (i)  all of the Parties' rights and obligations under
                         Article 3 in connection with the Research Program shall
                         cease in their entirety; provided that all amounts due
                         for research performed and costs incurred prior to the
                         date of such termination shall remain payable in
                         accordance with the provisions of Article 3;

                    (ii) all licenses granted by each Party to the other Party
                         under this Agreement with respect to such country shall
                         terminate (except as provided in Section 9.7.10 below);

                    (iii) the provisions of Section 9.7.2(a)(ii) (Wyeth's grant
                         of a non-exclusive license to Trubion under Wyeth
                         Applied Technology), with such changes as are

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                         appropriate in the context of such limited termination,
                         shall apply to a non-exclusive license to research,
                         Develop, Manufacture and Commercialize Licensed
                         Products in such country;

                    (iv) the provisions of Section 9.7.7 (Post-Termination
                         Transfer of Product Data and Filings and Existing
                         Trademarks), with such changes as are appropriate in
                         the context of such limited termination, shall apply
                         with respect to Product Data and Filings, and Existing
                         Trademarks, related to Licensed Products in such
                         country; and

                    (v)  the term "Territory" as used in this Agreement shall
                         thereafter exclude such country.

          9.7.3. EFFECT OF TERMINATION BY WYETH WITHOUT CAUSE.

               (a)  If this Agreement is terminated in its entirety by Wyeth
                    under Section 9.6.1, the following provisions shall apply:

                    (i)  all licenses granted by each Party to the other Party
                         under this Agreement shall terminate (except as
                         provided in Section 9.7.10 below);

                    (ii) the provisions of Section 9.7.2(a)(ii) (Wyeth's grant
                         of a non-exclusive license to Trubion under Wyeth
                         Applied Technology) shall apply;

                    (iii) the provisions of Section 9.7.7 (Post-Termination
                         Transfer of Product Data and Filings and Existing
                         Trademarks) shall apply;

                    (iv) the provisions of Section 9.7.8 (Manufacturing of
                         Licensed Products After Termination) shall apply; and

                    (v)  subject to the provisions of Section 9.9, this
                         Agreement shall be of no further force or effect.

               (b)  If this Agreement is terminated by Wyeth under Section 9.6.1
                    with respect to a Licensed Target in all countries, but not
                    in its entirety, the following provisions shall apply:

                    (i)  all of the Parties' rights and obligations under
                         Article 3 in connection with the Research Program shall
                         cease in their entirety; provided that all amounts due
                         for research performed and costs incurred prior to the
                         date

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                         of such termination shall remain payable in accordance
                         with the provisions of Article 3;

                    (ii) if such terminated Licensed Target is the CD20 Antigen,
                         Wyeth shall have no further obligation to reimburse
                         Trubion under Section 4.6 with respect to expenses
                         incurred after the effective date of termination;

                    (iii) all licenses granted by each Party to the other Party
                         under this Agreement with respect to Licensed Products
                         directed against such Licensed Target shall terminate
                         (except as provided in Section 9.7.10 below);

                    (iv) the provisions of Section 9.7.2(a)(ii) (Wyeth's grant
                         of a non-exclusive license to Trubion under Wyeth
                         Applied Technology), with such changes as are
                         appropriate in the context of such limited termination,
                         shall apply to a non-exclusive license to research,
                         Develop, Manufacture and Commercialize Licensed
                         Products directed against such Licensed Target;

                    (v)  the provisions of Section 9.7.7 (Post-Termination
                         Transfer of Product Data and Filings and Existing
                         Trademarks), with such changes as are appropriate in
                         the context of such limited termination, shall apply
                         with respect to Product Data and Filings, and Existing
                         Trademarks, related to Licensed Products directed
                         against such Licensed Target; and

                    (vi) the provisions of Section 9.7.8 (Manufacturing of
                         Licensed Products After Termination), with such changes
                         as are appropriate in the context of such limited
                         termination, shall apply with respect to Licensed
                         Products directed against such Licensed Target.

               (c)  If this Agreement is terminated by Wyeth under Section 9.6.1
                    with respect to all Licensed Targets in a country, but not
                    in its entirety, the following provisions shall apply:

                    (i)  if such country is a Major Market Country, all of the
                         Parties' rights and obligations under Article 3 in
                         connection with the Research Program shall cease in
                         their entirety; provided that all amounts due for
                         research performed and costs incurred prior to the date

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                         of such termination shall remain payable in accordance
                         with the provisions of Article 3; and if such country
                         is not a Major Market Country, all of the Parties'
                         rights and obligations under Article 3 in connection
                         with the Research Program shall continue;

                    (ii) all licenses granted by each Party to the other Party
                         under this Agreement with respect to such country shall
                         terminate (except as provided in Section 9.7.10 below);

                    (iii) the provisions of Section 9.7.2(a)(ii) (Wyeth's grant
                         of a non-exclusive license to Trubion under Wyeth
                         Applied Technology), with such changes as are
                         appropriate in the context of such limited termination,
                         shall apply to a non-exclusive license to research,
                         Develop, Manufacture and Commercialize Licensed
                         Products in such country;

                    (iv) the provisions of Section 9.7.7 (Post-Termination
                         Transfer of Product Data and Filings and Existing
                         Trademarks), with such changes as are appropriate in
                         the context of such limited termination, shall apply
                         with respect to Product Data and Filings, and Existing
                         Trademarks, related to Licensed Products in such
                         country; and

                    (v)  the term "Territory" as used in this Agreement shall
                         thereafter exclude such country.

          9.7.4. EFFECT OF TERMINATION BY WYETH FOR A MATERIAL SAFETY OR
               REGULATORY ISSUE. If this Agreement is terminated with respect to
               a Licensed Target by Wyeth under Section 9.6.2, the following
               provisions shall apply:

               (a)  all of the Parties' rights and obligations under Article 3
                    in connection with the Research Program shall continue;

               (b)  if such terminated Licensed Target is the CD20 Antigen,
                    Wyeth shall have no further obligation to reimburse Trubion
                    under Section 4.6 with respect to with respect to expenses
                    incurred after the effective date of termination;

               (c)  all licenses granted by each Party to the other Party under
                    this Agreement with respect to Licensed Products directed
                    against such Licensed Target shall terminate (except as
                    provided in Section 9.7.10 below);

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               (d)  unless the basis of termination under Section 9.6.2 is the
                    imposition of a clinical hold by a Regulatory Authority, a
                    determination by Wyeth to place a hold on further clinical
                    studies of a Licensed Product directed against such Licensed
                    Target (such determination to be made by Wyeth in accordance
                    with its standard procedures of addressing such safety
                    issues) or a withdrawal of a Licensed Product from the
                    market for patient safety reasons, whether voluntary or
                    otherwise, the provisions of Section 9.7.2(a)(ii) (Wyeth's
                    grant of a non-exclusive license to Trubion under Wyeth
                    Applied Technology), with such changes as are appropriate in
                    the context of such limited termination, shall apply to a
                    non-exclusive license to research, Develop, Manufacture and
                    Commercialize Licensed Products directed against such
                    Licensed Target;

               (e)  the provisions of Section 9.7.7 (Post-Termination Transfer
                    of Product Data and Filings and Existing Trademarks), with
                    such changes as are appropriate in the context of such
                    limited termination, shall apply with respect to Product
                    Data and Filings, and Existing Trademarks, related to
                    Licensed Products directed against such Licensed Target; and

               (f)  unless the basis of termination under Section 9.6.2 is the
                    imposition of a clinical hold by a Regulatory Authority, a
                    determination by Wyeth to place a hold on further clinical
                    studies of a Licensed Product directed against such Licensed
                    Target (such determination to be made by Wyeth in accordance
                    with its standard procedures of addressing such safety
                    issues) or a withdrawal of a Licensed Product from the
                    market for patient safety reasons, whether voluntary or
                    otherwise, the provisions of Section 9.7.8 (Manufacturing of
                    Licensed Products After Termination), with such changes as
                    are appropriate in the context of such limited termination,
                    shall apply with respect to Licensed Products directed
                    against such Licensed Target.

          9.7.5. POST-TERMINATION RIGHTS TO WYETH TECHNOLOGY AND TRUBION
               TECHNOLOGY. Except as otherwise expressly set forth in this
               Agreement, expiration or termination of this Agreement for any
               reason shall have no effect on Wyeth's rights with respect to the
               Wyeth Technology, and Trubion shall have no right, title or
               interest in or to any of the Wyeth Technology, and such
               expiration or termination shall have no effect on Trubion's
               rights with respect to the Trubion Technology, and Wyeth shall

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               have no right, title or interest in or to any of the Trubion
               Technology.

          9.7.6. POST-TERMINATION LICENSES TO WYETH TECHNOLOGY. In the event
               that Wyeth grants to Trubion a license under any Wyeth Technology
               pursuant to Section 9.7.1, 9.7.2, 9.7.3 or 9.7.4, such license
               shall include, inter alia, provisions whereby Trubion shall agree
               to comply with the applicable requirements of any Third Party
               license to which the use or exploitation of any such items may be
               subject including, but not limited to, the payment of royalties.

          9.7.7. POST-TERMINATION TRANSFER OF PRODUCT DATA AND FILINGS AND
               EXISTING TRADEMARKS. The following provisions shall apply in the
               event of termination by Trubion under Section 9.5 or termination
               by Wyeth under Section 9.6. To the extent permitted by applicable
               law, Wyeth shall assign and transfer to Trubion Wyeth's entire
               right, title and interest in and to Product Data and Filings,
               provide copies of all the Research Program Data, and license or
               otherwise transfer rights to Existing Trademarks that are
               necessary or useful for Trubion to continue to research, Develop,
               Manufacture or Commercialize Licensed Products as constituted at
               the time of termination. To the extent such Research Program
               Data, Product Data and Filings and other rights or items were
               previously transferred from Trubion to Wyeth, Wyeth shall perform
               such transfer at no cost to Trubion. To the extent such Research
               Program Data and Product Data and Filings were not previously
               transferred from Trubion to Wyeth, Trubion shall reimburse Wyeth
               for its reasonable out-of-pocket expenses in connection with such
               transfer, and such transfer shall be pursuant to an instrument in
               form and substance reasonably satisfactory to Trubion. Wyeth
               shall perform all other actions reasonably requested by Trubion
               to effect and confirm such transfer. After receipt of Trubion's
               request consistent with the foregoing, Wyeth shall provide to
               Trubion, within *** of receipt of such request, complete copies
               of such Product Data and Filings, including, without limitation,
               relevant clinical data, INDs, additional regulatory filings with
               FDA or other Regulatory Authorities, supplements or amendments
               thereto, all written correspondence with FDA or other Regulatory
               Authorities regarding the regulatory filings, and all existing
               written minutes of meetings and memoranda of conversations
               between Wyeth (including, to the extent practicable, Wyeth's
               investigators) and FDA or other Regulatory Authorities in Wyeth's
               possession (or in the possession of any of Wyeth's agents and
               subcontractors, such as contract research organizations used by
               Wyeth), to the extent Wyeth has the right

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               to access and provide to Trubion such Product Data and Filings,
               regarding such regulatory filings, each to the extent they relate
               to Licensed Products. Within thirty (30) days (or such later date
               as Trubion may request) after the date of receipt of Trubion's
               request, Wyeth shall execute and deliver a letter to the FDA or
               other Regulatory Authorities, in a form approved by Trubion,
               transferring ownership to Trubion of such regulatory filings, if
               any, filed in the name of Wyeth that are related to Licensed
               Products.

          9.7.8. MANUFACTURING OF LICENSED PRODUCTS AFTER TERMINATION. If (a)
               with respect to a particular Licensed Target, Trubion terminates
               this Agreement pursuant to Section 9.5 hereof or Wyeth terminates
               this Agreement pursuant to Section 9.6 hereof, and (b) Wyeth is
               engaged in the Manufacturing of a Licensed Product directed
               against such Licensed Target on the date the terminating Party
               gives notice of termination under Section 9.5 or Section 9.6, as
               the case may be, then Wyeth shall Manufacture such Licensed
               Product for Trubion and use Commercially Reasonable Efforts to
               supply Trubion with its entire requirements of such Licensed
               Product until (i) the *** anniversary of the effective date of
               such termination if at the time of such notice there shall have
               been filed a Regulatory Approval Application for such Licensed
               Product or (ii) the *** anniversary of the effective date of such
               termination if at the time of such notice there shall not have
               been filed a Regulatory Approval Application for such Licensed
               Product; provided, however, that (w) Wyeth shall not be required
               to conduct any activities to increase the scale on which it is
               then Manufacturing such Licensed Product, (x) Wyeth shall not be
               required to Manufacture or supply such Licensed Product in an
               amount in excess of its available capacity in the Manufacturing
               suite that was used by Wyeth for the Manufacture of such Licensed
               Product (taking into account the other uses Wyeth is making of
               the manufacturing suite as of the date of the Notice of
               Termination) or to change the location of the Manufacturing
               activities, (y) Wyeth shall have no obligation to maintain idle
               capacity in such manufacturing suite for purposes of meeting such
               Manufacturing obligations and (z) Wyeth may at its option assign
               to Trubion one or more of its Licensed Product manufacturing
               agreements with Third Parties, to the extent assignable, in lieu
               of continuing to contract directly with such Third Parties. The
               purchase price for such Licensed Product units actually
               Manufactured by Wyeth shall be at Wyeth's fully absorbed
               manufacturing cost plus ***, and Wyeth's obligations under this
               Section 9.7.8 shall be subject to the execution of a supply
               agreement and a quality agreement, each mutually

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               acceptable to both Parties, which agreements shall contain the
               terms set forth in this Section 9.7.8 and such other reasonable
               terms as mutually agreed by the Parties.

          9.7.9. POST-TERMINATION DISPOSITION OF INVENTORIES OF LICENSED
               PRODUCTS. Following termination of this Agreement with respect to
               one or more Licensed Targets, Wyeth and its sublicensees shall
               have the right to continue to sell their existing inventories of
               Licensed Products directed against such Licensed Targets for a
               period not to exceed *** after the effective date of such
               termination. Wyeth shall pay royalties and report on such sales,
               and maintain records thereon, in accordance with Sections 5.4,
               5.5 and 5.6, which shall survive termination for such purpose.

          9.7.10. CONTINUATION OF RIGHTS AND LICENSES UNDER SECTIONS 6.1.1 AND
               6.1.2. Notwithstanding anything in this Section 9.7 to the
               contrary, the Parties' rights and licenses set forth in Sections
               6.1.1 and 6.1.2 shall survive any expiration or termination of
               this Agreement.

          9.7.11. CONTINUATION OF OTHER RIGHTS AND OBLIGATIONS. Except as
               expressly provided to the contrary in this Section 9.7, in the
               event that a Party exercises any right that results in the
               termination of some, but not all, of the Parties' rights and
               obligations under this Agreement, all non-terminated rights and
               obligations of the Parties shall continue in full force and
               effect.

     9.8. MODIFICATION OF AGREEMENT TERMS BY WYETH. Without limiting any other
          legal or equitable remedies that Wyeth or Trubion may have, subject to
          Section 11.3, in the event that Wyeth elects to modify the terms of
          this Agreement as provided in Section 9.5, in lieu of terminating this
          Agreement under Section 9.5, with respect to one or more Licensed
          Targets identified by Wyeth in its Notice of Modification (the
          "Designated Target(s)"), the following terms shall apply:

          9.8.1. except as set forth in Section 9.8.4 below, all rights and
               obligations of the Parties under this Agreement shall continue in
               full force and effect, and shall not be subject to any unilateral
               modification by Wyeth; provided that, ***;

          9.8.2. all licenses granted by Trubion to Wyeth under this Agreement
               with respect to Licensed Products directed against each
               Designated Target shall remain in effect;

          9.8.3. all of the Parties' rights and obligations under Article 3 in
               connection with the Research Program shall cease in their

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               entirety; provided that all amounts due for research performed
               and costs incurred prior to the date of such termination shall
               remain payable in accordance with the provisions of Article 3;
               and

          9.8.4. only in the event of (i) a material breach by Trubion of
               Section 2.3.1 or 2.3.2; or (ii) a material breach by Trubion of
               Section 8.1(e), 8.2(c) or 8.2(d); or (iii) a material breach by
               Trubion of Section 8.2(a) (and, in the case of a material breach
               by Trubion of Section 8.2(a), only where Wyeth establishes that
               Trubion had knowledge, as of the Signing Date, that Trubion was
               not the sole and exclusive owner of the Trubion Patent Rights or
               that Trubion had placed, or suffered to be placed, any liens,
               charges or encumbrances on or against the Trubion Patent Rights);
               or (iv) if during the term of this Agreement, Trubion grants to a
               Third Party a right or license that conflicts in a material
               respect with Wyeth's then-existing rights under this Agreement
               pertaining to such Licensed Target(s), and thereby materially
               breaches Trubion's obligations hereunder, then:

               (a)  Wyeth's diligence obligations to use Commercially Reasonable
                    Efforts under Sections 4.1 and 4.10 shall no longer apply to
                    Licensed Products directed against such Designated Target;

               (b)  the amount of any Additional Research and Development
                    Expense Payment that Wyeth thereafter becomes obligated to
                    pay under Section 5.3 relating to Licensed Products directed
                    against such Designated Target shall be reduced by *** of
                    such amount; and

               (c)  the amounts of any royalties that Wyeth thereafter becomes
                    obligated to pay under Section 5.4 relating to Licensed
                    Products directed against such Designated Target shall be
                    reduced by *** of such amounts.

     9.9. SURVIVAL OF CERTAIN OBLIGATIONS. Expiration or termination of this
          Agreement shall not relieve the Parties of any obligation accrued or
          accruing before such expiration or termination (including situations
          where it becomes clear only after the time of such expiration or
          termination that such obligation had already accrued). The following
          provisions shall survive the expiration or termination of this
          Agreement: Article 1 (to the extent definitions are embodied in the
          following listed Articles and Sections); Sections 3.6.3, 3.7, 5.6,
          6.1.1, 6.1.2, 9.2, 9.5, 9.6, 9.7, 9.9, 9.10.2, 12.3, 12.6, 12.8, 12.9,
          12.10, 12.11 and 12.12; and Articles 7, 10 and 11. Any expiration or
          early termination of this Agreement shall be without prejudice to the
          rights of either Party against the other accrued or accruing

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          under this Agreement before expiration or termination, including,
          without limitation, the obligations (1) to provide research funding
          and reimbursement of expenses for activities undertaken prior to such
          expiration or termination under and in accordance with Sections 3.6.1,
          3.6.2, 4.6, 4.9, 6.1.3, 6.2.1(a), (c) and (d), 6.2.2(b) and (c), and
          6.2.3(b) and (c); and (2) to pay royalties for Licensed Products sold
          before such expiration or termination, and, to the extent permitted
          under Section 9.7.9, after expiration or termination in accordance
          with Section 5.4 (and subject to the related obligations under Section
          5.5); and (3) to pay any Additional Research and Development Expense
          Payments in connection with any events specified on Exhibit 5.3 that
          are achieved prior to such expiration or termination, but with respect
          to which the corresponding payments under Exhibit 5.3 were not paid
          prior to such expiration or termination.

     9.10. CHANGE OF CONTROL.

          9.10.1. DEFINITION. With respect to any Party, a "Change of Control"
               means an event in which: (a) any other person or group of persons
               (as the term "person" is used for purposes of Section 13(d) or
               14(d) of the Exchange Act) not then beneficially owning more than
               fifty percent (50%) of the voting power of the outstanding
               securities of such Party acquires or otherwise becomes the
               beneficial owner (within the meaning of Rule 13d-3 promulgated
               under the Exchange Act) of securities of such Party representing
               more than fifty percent (50%) of the voting power of the then
               outstanding securities of such Party with respect to the election
               of directors of such Party; or (b) such Person (i) consummates a
               merger, consolidation or similar transaction with another Person
               where the voting securities of such Party outstanding immediately
               preceding such transaction (or the voting securities issued with
               respect to the voting securities of such Party outstanding
               immediately preceding such transaction) represent less than fifty
               percent (50%) of the voting power of such Party or surviving
               entity, as the case may be, immediately following such
               transaction, (ii) sells or otherwise transfers to any Person(s)
               in one or more related transactions more than fifty percent (50%)
               of its consolidated total assets, or assets from which more than
               fifty percent (50%) of its consolidated operating income for its
               most recent financial year was derived, (iii) disposes by sale,
               assignment, exclusive license or otherwise of all or
               substantially all of its intellectual property rights, except for
               licenses under such intellectual property rights in the ordinary
               course of business and any isolated sale or assignment of
               specific items of intellectual property, or (iv) liquidates,
               dissolves or winds-up; or (c) with respect to Wyeth and with
               respect to Trubion, (at any time following any public offering of
               voting securities by Trubion), any "person" (as the

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               term "person" is used for the purposes of Sections 13(d) or 14(d)
               of the Exchange Act) other than Wyeth acquires nineteen and
               nine-tenths percent (19.9%) or more of the voting power of the
               then-outstanding voting securities of such Party.

          9.10.2. CHANGE OF CONTROL OF WYETH.

               (a)  In the event that any transaction results in a Change of
                    Control of Wyeth, Trubion shall be entitled to request
                    further written assurances from the successor in interest to
                    Wyeth (the "Successor Party") re-affirming the commitment of
                    the Successor Party to comply with the terms and conditions
                    of the Agreement. Such further written assurances shall be
                    delivered within *** of written request by Trubion. Trubion
                    may so request at any time during the *** period following
                    completion of the subject transaction. Subject to the
                    operation of Section 9.10.2(b) below, the failure of such
                    Successor Party to provide the requested written assurance
                    shall be deemed to be a material breach of the Agreement.

               (b)  In the event that in connection with, or during the ***
                    period following, a Change of Control of Wyeth, Wyeth or the
                    Successor Party is required, or voluntarily decides, to
                    divest itself of one or more Licensed Products, Wyeth or the
                    Successor Party, subject to any restrictions or limitations
                    imposed by the Federal Trade Commission or other
                    governmental agency on such divestiture, shall offer to
                    Trubion an exclusive opportunity to negotiate the
                    acquisition or license of all rights of Wyeth or such
                    Successor Party, as the case may be, to such Licensed
                    Product(s) on commercially reasonable terms. In the event
                    that Trubion and the Successor Party, after *** good faith
                    negotiations, are unable to conclude a definitive agreement
                    regarding the acquisition or license of such Licensed
                    Product(s), the Successor Party shall be entitled to divest
                    itself of such Licensed Product(s) to a party other than
                    Trubion; provided, however, no such divestiture to a Third
                    Party shall take place on terms more favorable to such Third
                    Party than those last offered by the Successor Party to
                    Trubion, without first offering such Licensed Product(s) to
                    Trubion on such more favorable terms. Such Third Party shall
                    be required to assume all of the Successor Party's
                    obligations owed to Trubion pursuant to this Agreement with
                    respect to the Licensed Product(s) so divested.

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               (c)  In the event of a Change of Control of Wyeth, the
                    restrictive covenants set forth in Sections 2.3.1 and 2.3.2
                    (the "Exclusivity Covenants") shall apply to the Successor
                    Party's then-existing Development and Commercialization
                    activities that otherwise would violate the Exclusivity
                    Covenants (the "Existing Activities"). In such event,
                    Trubion shall have the right, exercisable upon written
                    notice given by Trubion (an "Exercise Notice") within ***
                    after consummation of the Change of Control, to require such
                    Successor Party to engage in good faith discussions
                    regarding the terms and conditions on which such Successor
                    Party would pay reasonable financial consideration to
                    Trubion with respect to such Existing Activities. If Trubion
                    and such Successor Party do not agree on such terms and
                    conditions within *** after Trubion gives the Exercise
                    Notice (or such longer period as may be agreed to by such
                    parties), or if such Successor Party notifies Trubion in
                    writing during such *** period that it does not desire to
                    engage in such discussions, Trubion shall have the right,
                    exercisable upon written notice given by Trubion within ten
                    (10) days (i) after the end of such *** period (or such
                    longer period as agreed to by such parties) or (ii) after
                    receipt of such notice from such Successor Party, to require
                    such Successor Party to enter into an agreement to divest to
                    a Third Party either (a) the Existing Activities or (b) the
                    relevant CD20 Products or ***, as the case may be (such
                    Third Party, in the case of a divestiture of the relevant
                    CD20 Products or ***, to be reasonably acceptable to
                    Trubion) within *** after the date of such notice by
                    Trubion, subject to applicable governmental and regulatory
                    approval. If such Successor Party does not enter into an
                    agreement with a Third Party (such Third Party, in the case
                    of a divestiture of the relevant CD20 Products or ***, to be
                    reasonably acceptable to Trubion) to divest such Existing
                    Activities or such Products within such *** period (or if
                    such Successor Party does enter into such an agreement but
                    such agreement terminates after such *** period and such
                    divestiture is not consummated) or if such Successor Party
                    notifies Trubion in writing that it does not intend to
                    divest such Existing Activities or such Products, Trubion
                    shall have the right, exercisable within *** after the end
                    of such *** period (or upon termination of such agreement,
                    if later) to terminate, in its sole discretion, all
                    CD20-related licenses (only where such Existing Activities
                    relate to products directed against the CD20 Antigen which
                    would otherwise violate Wyeth's

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                    exclusivity covenants in Section 2.3.1 hereof) and/or all
                    *** (only where such Existing Activities relate to products
                    directed against the *** which would otherwise violate
                    Wyeth's exclusivity covenants in Section 2.3.2 hereof)
                    granted to Wyeth under the Agreement, on those terms and
                    subject to those conditions that would apply to a
                    termination by Wyeth without cause.

          9.10.3. CHANGE OF CONTROL OF TRUBION. In the event of a Change of
               Control of Trubion where the acquiring party is a top fifteen
               (15) pharmaceutical company (measured by market capitalization),
               Wyeth shall have the right to ***

10.  INDEMNIFICATION AND INSURANCE.

     10.1. INDEMNIFICATION BY WYETH. Wyeth will indemnify, defend and hold
          harmless Trubion, and each of its respective employees, officers,
          directors and agents (each, a "Trubion Indemnified Party") from and
          against any and all liability, loss, damage, expense (including
          reasonable attorneys' fees and expenses) and cost (collectively,
          "Liabilities") that the Trubion Indemnified Party may be required to
          pay to one or more Third Parties resulting from or arising out of:

               (a)  any claims of any nature pertaining to any act or omission
                    related to performance under this Agreement by, on behalf
                    of, or under the authority of Wyeth (other than by any
                    Trubion Indemnified Party) including, but not limited to,
                    research, Development, Manufacture or Commercialization of
                    Licensed Product(s) or any violation of applicable law, rule
                    or regulation by, on behalf of, or under the authority of
                    Wyeth (other than by any Trubion Indemnified Party); and/or

               (b)  any Wyeth representation or warranty set forth herein being
                    untrue in any material respect when made;

          except in each case, to the extent caused by the negligence or willful
          misconduct of Trubion or any other Trubion Indemnified Party.

     10.2. INDEMNIFICATION BY TRUBION. Trubion will indemnify, defend and hold
          harmless Wyeth and its sublicensees, distributors and each of its and
          their respective employees, officers, directors and agents (each, a
          "Wyeth Indemnified Party") from and against any and all Liabilities
          that the Wyeth Indemnified Party may be required to pay to one or more
          Third Parties resulting from or arising out of:

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               (a)  any claims of any nature pertaining to any act or omission
                    related to performance under this Agreement by, on behalf
                    of, or under the authority of Trubion (other than by any
                    Wyeth Indemnified Party) or any violation of applicable law,
                    rule or regulation by, on behalf of, or under the authority
                    of Trubion (other than by any Wyeth Indemnified Party);
                    and/or

               (b)  any Trubion representation or warranty set forth herein
                    being untrue in any material respect when made;

          except in each case, to the extent caused by the negligence or willful
          misconduct of Wyeth or any other Wyeth Indemnified Party.

     10.3. PROCEDURE. Each Party will notify the other in the event it becomes
          aware of a claim for which indemnification may be sought hereunder. In
          case any proceeding (including any governmental investigation) shall
          be instituted involving any Party in respect of which indemnity may be
          sought pursuant to this Article 10, such Party (the "Indemnified
          Party") shall promptly notify the other Party (the "Indemnifying
          Party") in writing within fifteen (15) days and the Indemnifying Party
          and Indemnified Party shall meet to discuss how to respond to any
          claims that are the subject matter of such proceeding. The
          Indemnifying Party, upon request of the Indemnified Party, shall
          retain counsel reasonably satisfactory to the Indemnified Party to
          represent the Indemnified Party and shall pay the fees and expenses of
          such counsel related to such proceeding. The Indemnified Party agrees
          to cooperate fully with the Indemnifying Party in the defense of any
          such claim, action or proceeding, or any litigation resulting from any
          such claim. In any such proceeding, the Indemnified Party shall have
          the right to retain its own counsel, but the fees and expenses of such
          counsel shall be at the expense of the Indemnified Party unless (a)
          the Indemnifying Party and the Indemnified Party shall have mutually
          agreed to the retention of such counsel or (b) the named parties to
          any such proceeding (including any impleaded parties) include both the
          Indemnifying Party and the Indemnified Party and representation of
          both Parties by the same counsel would be inappropriate due to actual
          or potential differing interests between them. All such fees and
          expenses shall be reimbursed as they are incurred. The Indemnifying
          Party shall not be liable for any settlement of any proceeding
          effected without its written consent, but if settled with such consent
          or if there be a final judgment for the plaintiff, the Indemnifying
          Party agrees to indemnify the Indemnified Party from and against any
          loss or liability by reason of such settlement or judgment. The
          Indemnifying Party shall not, without the written consent of the
          Indemnified Party, effect any settlement of any pending or threatened
          proceeding in respect of which the Indemnified Party is, or arising
          out of the same set of facts could have been, a party and indemnity
          could have been sought hereunder by the Indemnified Party, unless such
          settlement includes an unconditional release

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          of the Indemnified Party from all liability on claims that are the
          subject matter of such proceeding.

     10.4. INSURANCE. Each Party shall use Commercially Reasonable Efforts to
          obtain and maintain, during the term of this Agreement, commercial
          general liability insurance, including products liability insurance,
          with reputable and financially secure insurance carriers to cover its
          indemnification obligations under Sections 10.1 or 10.2, as
          applicable, or self-insurance, in each case with limits of not less
          than *** per occurrence and in the aggregate. Insurance shall be
          procured with carriers having an A.M. Best Rating of A-VII or better.

11.  DISPUTE RESOLUTION.

     11.1. GENERAL. Any controversy, claim or dispute arising out of or relating
          to this Agreement shall be settled, if possible, through good faith
          negotiations between the Parties. If, however, the Parties are unable
          to settle such dispute after good faith negotiations, the matter shall
          be referred to the Executive Officers to be resolved by negotiation in
          good faith as soon as is practicable but in no event later than thirty
          (30) days after referral. Such resolution, if any, of a referred issue
          shall be final and binding on the Parties.

     11.2. FAILURE OF EXECUTIVE OFFICERS TO RESOLVE DISPUTE. If the Executive
          Officers are unable to settle the dispute after good faith negotiation
          in the manner set forth above, either Party (including its successors
          and permitted assigns but excluding its Affiliates unless an Affiliate
          is a successor or permitted assign) may seek resolution of the dispute
          through any remedies available at law or in equity from any court of
          competent jurisdiction.

     11.3. DISCLAIMER OF CONSEQUENTIAL AND PUNITIVE DAMAGES. Subject to and
          without limiting the indemnification obligations of each Party under
          Article 10, under no circumstances shall either Party be liable to the
          other Party for consequential or punitive damages arising out of or
          relating to this Agreement or any breach thereof. Both Parties hereby
          disclaim such damages.

12.  MISCELLANEOUS.

     12.1. PERIODIC EXECUTIVE MEETINGS. The Chief Executive Officer of Trubion,
          the Senior Vice President, Research and Development of Trubion, the
          Executive Vice President and General Manager of the Wyeth
          Pharmaceuticals Biopharma Business Unit and the Executive Vice
          President and Operating Officer of Wyeth's Research Division (and such
          other executive officers of the Parties as may be designated from time
          to time by the Parties) shall meet from time to time during the first
          *** of the term of this Agreement to review and discuss the Parties'
          activities under

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          this Agreement. Such meetings will be held on a quarterly basis or
          such other periodic basis as such executive officers decide, and will
          take place in locations selected by such executive officers. Such
          meetings may take place by telephone or video conference.

     12.2. ASSIGNMENT. Neither this Agreement nor any interest hereunder shall
          be assignable by either Party, without the prior written consent of
          the other Party, which consent shall not be unreasonably withheld or
          delayed, except a Party may make such an assignment without the other
          Party's consent to Affiliates or to a successor to substantially all
          of the business of such Party to which this Agreement relates, whether
          in merger, sale of stock, sale of assets or other transaction. This
          Agreement shall be binding upon the successors and permitted assigns
          of the Parties, and the name of a Party appearing herein shall be
          deemed to include the names of such Party's successors and permitted
          assigns to the extent necessary to carry out the intent of this
          Agreement. In addition to the foregoing, Trubion may assign its right,
          in whole or part, to receive payments under this Agreement; provided,
          however, Trubion shall notify Wyeth of its intention to do so and
          shall provide Wyeth an opportunity for at least *** to negotiate in
          good faith the purchase of any such right Trubion intends to so
          assign. Any assignment not in accordance with this Section 12.2 shall
          be void.

     12.3. 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 the Agreement.

     12.4. FORCE MAJEURE. Neither Party shall be liable to the other for delay
          or failure in the performance of the obligations on its part contained
          in this Agreement if and to the extent that such failure or delay is
          due to circumstances beyond its control which it could not have
          avoided by the exercise of reasonable diligence. It shall notify the
          other Party promptly should such circumstances arise, giving an
          indication of the likely extent and duration thereof, and shall use
          all Commercially Reasonable Efforts to resume performance of its
          obligations as soon as practicable; provided, however, that neither
          Party shall be required to settle any labor dispute or disturbance.

     12.5. NON-SOLICITATION. During the period between the Effective Date and
          the later of (a) the end of *** or (b) the date ***, but in the case
          of (a) and (b) not later than the *** of the Effective Date, neither
          Trubion nor the Wyeth pharmaceuticals business operating in the United
          States ("U.S. Wyeth Pharmaceuticals") shall solicit for employment any
          key or technical employee(s) of the other Party who become known to
          U.S. Wyeth Pharmaceuticals or Trubion, as the case may be, through the
          transactions contemplated by this Agreement without the other's prior
          written consent (which consent may be granted or denied in the other's
          sole discretion);

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          provided, however, that nothing in this Section 12.5 shall prohibit
          U.S. Wyeth Pharmaceuticals or Trubion, as the case may be, from hiring
          any employees of the other who respond to general employment
          solicitations not targeted at the employees of the other, advertised
          employment opportunities, or hiring by the other by personnel not
          working on the transactions contemplated by this Agreement or who are
          not otherwise directly or indirectly exposed to the personnel working
          thereon.

     12.6. CORRESPONDENCE AND NOTICES.

          12.6.1. ORDINARY NOTICES. Correspondence, reports, documentation, and
               any other communication in writing between the Parties in the
               course of ordinary implementation of this Agreement shall be
               delivered by hand, sent by facsimile transmission (receipt
               verified), or by airmail to the employee or representative of the
               other Party who is designated by such other Party to receive such
               written communication.

          12.6.2. EXTRAORDINARY NOTICES. Extraordinary notices and other
               communications hereunder (including, without limitation, any
               notice of force majeure, breach, termination, change of address,
               etc.) shall be in writing and shall be deemed given if delivered
               personally or by facsimile transmission (receipt verified),
               mailed by registered or certified mail (return receipt
               requested), postage prepaid, or sent by nationally recognized
               express courier service, to the Parties at the following
               addresses (or at such other address for a Party as shall be
               specified by like notice; provided, however, that notices of a
               change of address shall be effective only upon receipt thereof):

               All correspondence to Wyeth shall be addressed as follows:

                    Wyeth Pharmaceuticals
                    500 Arcola Road
                    Collegeville, Pennsylvania 19426
                    Attn: Senior Vice President, Corporate Business Development
                    Fax: (484) 865-6476

               with a copy to:

                    Wyeth
                    5 Giralda Farms
                    Madison, New Jersey 07940
                    Attn: Executive Vice President and General Counsel
                    Fax: (973) 660-7156

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               All correspondence to Trubion shall be addressed as follows:

                    Trubion Pharmaceuticals, Inc.
                    2401 4th Avenue
                    Suite 1050
                    Seattle, Washington 98121
                    Attn: President & CEO
                    Fax: (206) 838-0503

               with a copy to:

                    Trubion Pharmaceuticals, Inc.
                    Vice President, Legal Affairs
                    2401 4th Avenue
                    Suite 1050
                    Seattle, Washington 98121
                    Fax: (206) 838-0503

     12.7. AMENDMENT. No amendment, modification or supplement of any provision
          of this Agreement shall be valid or effective unless made in writing
          and signed by a duly authorized officer of each Party.

     12.8. WAIVER. No provision of the Agreement shall be waived by any act,
          omission or knowledge of a Party or its agents or employees except by
          an instrument in writing expressly waiving such provision and signed
          by a duly authorized officer of the waiving Party. The waiver by
          either of the Parties of any breach of any provision hereof by the
          other Party shall not be construed to be a waiver of any succeeding
          breach of such provision or a waiver of the provision itself.

     12.9. SEVERABILITY. If any clause or portion thereof in this Agreement is
          for any reason held to be invalid, illegal or unenforceable, the same
          shall not affect any other portion of this Agreement, as it is the
          intent of the Parties that this Agreement shall be construed in such
          fashion as to maintain its existence, validity and enforceability to
          the greatest extent possible. In any such event, this Agreement shall
          be construed as if such clause of portion thereof had never been
          contained in this Agreement, and there shall be deemed substituted
          therefor such provision as will most nearly carry out the intent of
          the Parties as expressed in this Agreement to the fullest extent
          permitted by applicable law.

     12.10. DESCRIPTIVE HEADINGS. The descriptive headings of this Agreement are
          for convenience only, and shall be of no force or effect in construing
          or interpreting any of the provisions of this Agreement.

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     12.11. GOVERNING LAW. This Agreement shall be governed by and interpreted
          in accordance with the substantive laws of the State of New York,
          without regard to conflict of law principles thereof.

     12.12. ENTIRE AGREEMENT OF THE PARTIES. This Agreement constitutes and
          contains the complete, final and exclusive understanding and agreement
          of the Parties and cancels and supersedes any and all prior
          negotiations, correspondence, understandings and agreements, whether
          oral or written, among the Parties respecting the subject matter
          hereof and thereof, including, but not limited to, that certain
          Non-Disclosure Agreement of the Parties effective May 27, 2004. For
          the avoidance of doubt, disclosures made under such Confidentiality
          Agreement shall continue to be subject to the terms of this Agreement
          as if first disclosed pursuant hereto. Except as expressly set forth
          in this Agreement, neither Party shall have any other obligations,
          whether by implication or otherwise, with respect to the research,
          Development, Manufacture or Commercialization of Licensed Products.

     12.13. INDEPENDENT CONTRACTORS. Both Parties are independent contractors
          under this Agreement. Nothing herein contained shall be deemed to
          create an employment, agency, joint venture or partnership
          relationship between the Parties hereto or any of their agents or
          employees, or any other legal arrangement that would impose liability
          upon one Party for the act or failure to act of the other Party.
          Neither Party shall have any express or implied power to enter into
          any contracts or commitments or to incur any liabilities in the name
          of, or on behalf of, the other Party, or to bind the other Party in
          any respect whatsoever.

     12.14. COUNTERPARTS. This Agreement may be executed in any number of
          counterparts, each of which need not contain the signature of more
          than one Party but all such counterparts taken together shall
          constitute one and the same agreement. Facsimile signatures shall be
          binding upon the Parties and shall be treated as if originals.

     IN WITNESS WHEREOF, duly authorized representatives of the Parties have
duly executed this Agreement to be effective as of the Signing Date.

WYETH,
ACTING THROUGH ITS
WYETH PHARMACEUTICALS DIVISION          TRUBION PHARMACEUTICALS, INC.

By /s/ William M. Haskel                By /s/ Peter A. Thompson
   ----------------------------------      -------------------------------------
Name: William M. Haskel                 Name: Peter A. Thompson, M.D.
Title: Vice President                   Title: President & CEO

                                                                              97
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                                                                  EXECUTION COPY

                                  EXHIBIT 1.122
                                     TRU-015

     ***

     As of the Signing Date, TRU-015 is investigated in the Phase IIa Clinical
Study.

<PAGE>

                                                                  EXECUTION COPY

                                  EXHIBIT 1.129
                              TRUBION PATENT RIGHTS

         ***

<PAGE>

                                                                  EXECUTION COPY

                                  EXHIBIT 1.132
                         TRUBION THIRD PARTY AGREEMENTS

     ***

<PAGE>

                                                                  EXECUTION COPY

                                  EXHIBIT 3.2.1
                            TRUBION'S "MILESTONE ONE"

MILESTONE #1

Defined in Trubion's internal project management process, which may be modified
from time to time.

The following specifications are determined:

     -    Scientific Rationale that supports the therapeutic potential

               -    Mechanism of Action (MOA)

     -    Specific biochemical and therapeutic properties (targeted)

               -    Binding Domain

               -    Target

               -    In vivo activity

               -    Safety

               -    pk

     -    Market rationale (preliminary) for product profile

               -    Economics (COGs)

     -    Clinical rationale (preliminary) for product profile

     -    Alliance Opportunity assessment

     -    Intellectual property assessment

<PAGE>

                                                                  EXECUTION COPY

                                  EXHIBIT 3.2.4
                                EXCLUDED TARGETS

                 GENBANK ACCESSION NUMBER (AMINO ACID SEQUENCE)

     ***

<PAGE>

                                                                  EXECUTION COPY

                                   EXHIBIT 4.4
                       ADVERSE EVENT REPORTING PROCEDURES

The terms adverse event or experience (AE) and adverse drug reaction (ADR), used
in this Exhibit 4.4 shall have the meanings set forth in worldwide reporting
regulations. The Parties agree to comply with any and all governmental laws,
regulations and orders that are applicable now and in the future in connection
with product safety collection and reporting.

The Parties agree to meet after the Effective Date to establish a detailed
Safety Agreement outlining the pharmacovigilance responsibilities of each Party
including but not limited to: AE or ADR reporting including literature review
and associated reporting; AE or ADR follow-up reporting; preparation and
submission of all safety reports to the Regulatory Authorities as required by
local laws and/or regulations in the Territory; maintaining the global safety
database; all interactions with health authorities regarding safety; periodic
submissions; labeling modifications; safety monitoring and detection; and safety
measures (e.g., Dear Doctor Letter, restriction on distribution). Wyeth shall
maintain the global safety database for the Licensed Products.

Notwithstanding the foregoing and until such time as the Safety Agreement is
executed, to the extent Trubion has or receives any information regarding any
AE/ADR which may be related to the use of any Licensed Product or to Licensed
Product Development, Trubion shall promptly forward such information as follows:

     -    Fatal or life-threatening serious AE(s)/ADR(s) judged by either the
          investigator and/or sponsor to be reasonably related to the Licensed
          Product(s) Development/protocol shall be transmitted to Wyeth within
          three (3) calendar days from the date received by Trubion.

     -    All other serious AE(s)/ADR(s) not fatal or life-threatening but
          judged by either the investigator and/or sponsor to be reasonably
          related to the Licensed Product(s) Development/protocol shall be
          transmitted to Wyeth within five (5) calendar days from the date
          received by Trubion.

AE/ADR information may be transmitted to Wyeth by:

     a.   Facsimile: 610-989-5544 OR

     b.   Overnight courier to:

               Global Safety Surveillance & Epidemiology
               Wyeth Research
               GSSE Triage Unit
               Dock E
               500 Arcola Road
               Collegeville, PA 19426

<PAGE>

                                                                  EXECUTION COPY

                                  EXHIBIT 5.2A
                            STOCK PURCHASE AGREEMENT

                          TRUBION PHARMACEUTICALS, INC.

                         COMMON STOCK PURCHASE AGREEMENT

          This Common Stock Purchase Agreement (this "Agreement") is made as of
December __, 2005 by and between Trubion Pharmaceuticals, Inc., a Delaware
corporation (the "Company"), and Wyeth, a Delaware corporation (the
"Purchaser").

                                    RECITALS

          A. The Purchaser and the Company are entering into a collaboration
agreement of even date herewith (the "Collaboration Agreement");

          B. In connection with the Collaboration Agreement, Purchaser desires
to purchase from the Company shares of its Common Stock (the "Common Stock"),
concurrently with and conditioned upon the closing of the Company's initial
public offering, upon the terms and conditions set forth herein;

          C. The Company and the Purchaser wish to set forth the terms and
conditions upon which the Company will sell the Common Stock to the Purchaser;
and

          D. Concurrent with the execution of this Agreement, the Company and
Purchaser are entering into an amendment (the "Rights Agreement Amendment") to
the Company's Amended and Restated Investor Rights Agreement (the "Rights
Agreement") to provide Purchaser with certain rights and obligations thereunder
upon the issuance of the Common Stock hereunder.

          NOW, THEREFORE, in consideration of the premises and mutual covenants
and conditions contained herein, the Company and the Purchaser hereby agree as
follows:

                                    ARTICLE I

                           PURCHASE AND SALE OF SHARES

     1.1 Purchase Price and Closing. Subject solely to the conditions set forth
in Sections 1.2 - 1.5 and Article IV hereof, the Company will issue and sell to
the Purchaser and, subject to the terms and conditions set forth in this
Agreement, the Purchaser will purchase from the Company (the "Sale"), that
number of shares of Common Stock (the "Shares") equal to the quotient obtained
by dividing Twenty-Five Million Dollars ($25,000,000) (the "Investment Amount")
by the per-share price to the public (the "IPO Price") of shares of Common Stock
in the Company's first underwritten, firm commitment public offering (the "IPO")
pursuant to an effective registration statement (the "Registration Statement")
under

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the Securities Act of 1933, as amended (the "Securities Act"). The per share
price to Purchaser shall be the IPO Price. The purchase and sale will take place
at a closing (the "Closing") to be held on the date, at the location and
simultaneously with the closing of the IPO, subject to the satisfaction of all
of the conditions to the Closing specified in Article IV herein. At the Closing
the Company will issue and deliver a certificate evidencing the Shares to the
Purchaser against payment of the full purchase price therefor by wire transfer
of immediately available funds to an account designated by the Company.

     1.2 Maximum Share Number. Notwithstanding Section 1.1 above, in the event
the number of Shares would otherwise constitute more than (i) nineteen and
nine-tenths percent (19.9%) of the Actual Voting Power (as defined in Section
5.1(i)) or (ii) twenty percent (20%) of the number of shares issued in the IPO
(including any shares covered by a related registration statement filed pursuant
to Rule 462(b) of the Securities Act but excluding any shares issued or to be
issued in an overallotment option), then in either case (i) or (ii) above the
Investment Amount (and correspondingly the number of shares purchased by the
Purchaser) shall be reduced by the minimum dollar amount and share amount
necessary to avoid either such event.

     1.3 Restrictions on Transfer. Pursuant to the Rights Agreement Amendment,
Purchaser agrees and acknowledges that the restrictions set forth in Sections
2.1 and 2.12 of the Rights Agreement shall apply to Purchaser and the Shares.

     1.4 HSR Act. Prior to the execution of the Collaboration Agreement and this
Agreement, the parties made certain filings under the Hart-Scott Rodino
Antitrust Improvements Act of 1976, as amended (the "HSR Act"). If either party
concludes in good faith that additional filings or proceedings are necessary or
desirable as a result of the transactions contemplated hereby either as a result
of the signing of this Agreement or in connection with the Closing or otherwise,
the parties agree to promptly file such additional notices, applications and
documents that may be required under the HSR Act, or any other required foreign
or domestic competition law (collectively, the "Competition Laws") and all
applicable additional filings fees associated therewith shall be paid by the
party required to so pay such additional filing fees under the applicable
Competition Law(s). In connection therewith, the Company and Purchaser each
shall use their commercially reasonable efforts to take such actions as may be
required to cause the expiration or early termination of the notice periods
under the Competition Laws as promptly as possible and to resolve such
objections, if any, as may be asserted with respect to the transactions
contemplated by this Agreement under the Competition Laws; provided, however,
that notwithstanding the foregoing, neither party shall agree to any change or
amendment to this Agreement unless such change or amendment is agreed by the
other party in advance. Nothing in this Agreement shall require either party or
any subsidiary or affiliate of either party to sell, hold separate, license or
otherwise dispose of any assets or conduct its business in a specified manner,
or agree or proffer to sell, hold separate, license or otherwise dispose of any
assets or conduct its business in a specified manner, or permit or agree to the
sale, holding separate, licensing or other disposition of any assets of either
party or any subsidiary or affiliate of either party, whether as a condition to
obtaining any approval from, or to avoid potential litigation or administrative
action by, a governmental entity or any other person or for any other reason.

     1.5 Termination of Purchase Right and Obligation. Notwithstanding any
provision of this Agreement to the contrary, Purchaser's right and obligation to
purchase, and the Company's right and obligation to sell, the Shares shall
terminate if the closing of the IPO has not occurred prior to the earliest to
occur of the following:

          (a) The termination of the Collaboration Agreement; or

          (b) The Company (1) undergoes a Change of Control (as defined in
Section 5.1(iv));; provided, however, the following shall be deemed to not be a
Change of Control for purposes of this

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Section 1.5(b): (i) a transaction effected exclusively for the purpose of
changing the domicile of the Company, or (ii) an equity financing in which the
Company is the surviving corporation, or (2) engages in a merger, consolidation,
reorganization or similar transaction in which the surviving entity has a class
of equity securities registered under Section 12 of the Exchange Act (as defined
below).

                                   ARTICLE II

                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

     The Company hereby represents and warrants to the Purchaser as follows:

     2.1 Corporate Action. The Company has all necessary corporate power and has
taken all corporate action required to enter into and perform this Agreement and
the Rights Agreement Amendment (collectively, the "Financing Documents"). The
Financing Documents have been duly executed and delivered, and constitute valid,
legal, binding and enforceable obligations of the Company, enforceable in
accordance with their terms, except (i) as limited by applicable bankruptcy,
insolvency, reorganization, moratorium and other laws of general application
affecting enforcement of creditors' rights generally and (ii) as limited by laws
relating to the availability of specific performance, injunctive relief or other
equitable remedies. The issuance, sale and delivery of the Shares in accordance
with this Agreement have been duly authorized by all necessary corporate action
on the part of the Company. The issuance of the Shares is not subject to
preemptive rights or other preferential rights in any present stockholders of
the Company that have not been waived and will not conflict with any provision
of any agreement or instrument to which the Company is a party or by which it or
its property is bound and to which the Company has not obtained appropriate
waivers.

     2.2 No Conflict. The execution and delivery of this Agreement by the
Company does not, and the consummation of the transactions contemplated hereby
will not, conflict with, or result in any violation of, or default under (with
or without notice or lapse of time, or both), or give rise to a right of
termination, cancellation, modification or acceleration of any obligation under
(i) any provision of the Certificate of Incorporation of the Company or Bylaws
of the Company, (ii) any material mortgage, indenture, lease, contract or other
agreement or instrument, permit, concession, or license to which the Company or
any of its properties or assets is subject or (iii) any judgment, order, decree,
applicable to the Company or its properties or assets. To the Company's
knowledge as of the date hereof, no provision of any applicable law, rule or
regulation and no judgment, order, decree or injunction applicable to the
Company or its properties or assets shall prohibit the consummation of the
Closing nor shall the Closing result in any violation of any such law, rule,
regulation, judgment, order, decree or injunction.

     2.3 Status of Shares. The Shares, when issued and delivered in accordance
with the terms hereof and after payment of the purchase price therefor, will be
duly authorized, validly issued, fully-paid and non-assessable, issued in
compliance with applicable state and federal securities laws (subject, in part,
to the representations and warranties of Purchase in Article III hereof) and
free of restrictions on transfer other than restrictions on transfer under the
Financing Documents and applicable state and federal securities laws.

     2.4 Organization, Good Standing and Qualification. The Company is a
corporation duly organized, validly existing and in good standing under the laws
of the State of Delaware and has all requisite corporate power and authority to
carry on its business.

     2.5. Collaboration Agreement. The Collaboration Agreement has been duly
authorized, executed, and delivered by the Company and constitutes a valid and
binding obligation of the Company, enforceable in accordance with its terms,
except (i) as limited by applicable bankruptcy, insolvency,

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reorganization, moratorium and other laws of general application affecting
enforcement of creditors' rights generally and (ii) as limited by laws relating
to the availability of specific performance, injunctive relief or other
equitable remedies.

     2.6 Final Prospectus and Registration Statement. The Company, acknowledging
that the Purchaser will be relying on the accuracy and completeness of the
Company's disclosure in connection with the IPO, warrants to the Purchaser that
the Prospectus (as defined below) used in connection with the Company's IPO will
comply, at the time of filing or use, with the requirements of the Securities
Act, and the Prospectus filed or used in connection with the IPO will not, at
such time, contain an untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary to make the statements
therein, in light of the circumstances under which they were made, not
misleading; the Registration Statement, when it becomes effective, will comply,
in all material respects, with the requirements of the Securities Act; and the
Registration Statement will not, when it becomes effective, contain an untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary to make the statements therein; provided, however,
that the Company makes no warranty with respect to any statement contained in
the Registration Statement or a prospectus in reliance upon and in conformity
with information concerning the Purchaser that is furnished by the Purchaser
expressly for use therein. "Prospectus" means the final prospectus (as such term
is defined in Section 2(a)(10) of the Securities Act) as first filed with the
SEC pursuant to paragraph (1) or (4) of Rule 424(b) of the Securities Act.

                                   ARTICLE III

            REPRESENTATIONS AND WARRANTIES AND COVENANTS BY PURCHASER

     The Purchaser represents and warrants and covenants to the Company that:

     3.1 Purchaser is an "accredited investor" as defined in Rule 501(a) under
the Securities Act of 1933, as amended.

     3.2 Purchaser will acquire the Shares for its own account, for the purpose
of investment and not with a view to distribution or resale thereof.

     3.3 Purchaser has all necessary corporate power and has taken all corporate
action required to enter into and perform the Financing Documents. The Financing
Documents have been duly executed and delivered, and constitute valid, legal,
binding and enforceable obligations of Purchaser, enforceable in accordance with
their terms, except (i) as limited by applicable bankruptcy, insolvency,
reorganization, moratorium and other laws of general application affecting
enforcement of creditors' rights generally and (ii) as limited by laws relating
to the availability of specific performance, injunctive relief or other
equitable remedies.

     3.4 Purchaser has taken no action which would give rise to any claim
against the Company by any other person for any brokerage commissions, finders'
fees or the like relating to this Agreement or the transactions contemplated
hereby.

     3.5 Purchaser has had the opportunity to ask questions of and receive
answers from representatives of the Company concerning the terms of the offering
of the Shares and to obtain additional information concerning the Company and
its business.

     3.6 The acquisition by the Purchaser of the Shares shall constitute a
confirmation of these representations and warranties made by the Purchaser as of
the Closing. Purchaser understands that the

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Shares are "restricted securities" under the Securities Act and have not been
registered under the Securities Act in reliance upon an exemption for non-public
offerings. The Purchaser further represents that it understands and agrees that,
until registered under the Securities Act or transferred pursuant to the
provisions of Rule 144 as promulgated by the Commission, all certificates
evidencing any of the Shares, whether upon initial issuance or upon any transfer
thereof, shall be subject to the transfer restrictions and bear the legends set
forth in Section 2.1 of the Rights Agreement.

     3.7 To the Purchaser's knowledge as of the date hereof, no provision of any
applicable law, rule or regulation and no judgment, order, decree or injunction
applicable to the Purchaser or its properties or assets shall prohibit the
consummation of the Closing nor shall the Closing result in any violation of any
such law, rule, regulation, judgment, order, decree or injunction.

                                   ARTICLE IV

                              CONDITIONS TO CLOSING

     4.1 Conditions of the Purchaser's Obligation. The obligation of the
Purchaser to purchase and pay for the Shares at the Closing is subject to the
satisfaction of the following conditions:

          (a) Documentation at Closing. The Purchaser shall have received prior
to or at the Closing all of the following documents or instruments, or evidence
of completion thereof, each in form and substance satisfactory to the Purchaser:

               (i) A copy of the Certificate of Incorporation of the Company,
certified by the Secretary of State of the State of Delaware, a copy of the
resolutions of the Board of Directors of the Company evidencing the approval of
this Agreement, the issuance of the Shares and the other matters contemplated
hereby, and a copy of the Bylaws of the Company, all of which shall have been
certified by the Secretary of the Company to be true, complete and correct in
every particular, and certified copies of all documents evidencing other
necessary corporate or other action and governmental approvals, if any, with
respect to this Agreement and the Shares.

               (ii) A customary opinion of counsel to the Company covering the
matters set forth in Exhibit A hereto.

               (iii) A certificate of the Secretary of the Company which shall
certify the names of the officers of the Company authorized to sign this
Agreement, the certificate for the Shares and the other documents, instruments
or certificates to be delivered pursuant to this Agreement by the Company or any
of its officers, together with the true signatures of such officers.

               (iv) A certificate of the President of the Company stating (A)
that the representations and warranties made by the Company in this Agreement
are true and correct in all material respects at the date hereof and as of the
Closing with the same force and effect as though all such representations and
warranties had been made as of the Closing, and (B) that all covenants and
conditions required to be performed prior to or at the Closing have been
performed as of the Closing.

               (v) A Certificate of Good Standing for the Company from the
Secretary of State of the State of Delaware, dated as of a recent date.

          (b) Performance. The Company shall have performed and complied with in
all material respects all agreements, obligations and conditions contained in
this Agreement that are required to be performed or complied with by it on or
before the Closing.

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          (c) Consents, Waivers, Etc. The Company shall have obtained all
consents or waivers, if any, necessary to execute and deliver this Agreement,
issue the Shares and to carry out the transactions contemplated hereby and
thereby and the waiting period applicable to this Agreement and the
Collaboration Agreement under the HSR Act (or any other applicable Competition
Laws) shall have expired or terminated early. All corporate and other action and
governmental filings necessary to effect the terms of this Agreement, the
issuance of the Shares and other agreements and instruments executed and
delivered by the Company in connection herewith shall have been made or taken,
except for any post-sale filing that may be required under federal or state
securities laws.

          (d) Rights Agreement Amendment. The Rights Agreement Amendment shall
have been executed by the Company and by the holders of the requisite majority
of Registrable Securities (as such term is defined in the Rights Agreement);
provided, however, the parties acknowledge that subsequent to the date hereof
the Rights Agreement may be further amended in accordance with its terms;
provided, further, however, Purchaser shall be required to consent to such
amendment or be provided substantially equivalent rights in such amendment or
another written agreement with the Company.

          (e) Collaboration Agreement. The Collaboration Agreement shall have
been duly authorized, executed, and delivered by the Company and constitute a
valid and binding obligation of the Company, enforceable in accordance with its
terms, except (i) as limited by applicable bankruptcy, insolvency,
reorganization, moratorium and other laws of general application affecting
enforcement of creditors' rights generally and (ii) as limited by laws relating
to the availability of specific performance, injunctive relief or other
equitable remedies. The Purchaser shall not have the right to terminate the
Collaboration Agreement for cause pursuant to Section 9.5 thereof (provided,
however, if Purchaser's right to so terminate the Collaboration Agreement for
cause is solely dependent on the lapsing on any applicable "cure" period
pursuant to Section 9.5 thereof, solely for purposes of this Section 4.1(e),
Purchaser shall be deemed to have the right to terminate the Collaboration
Agreement for cause notwithstanding the failure of any such cure period to have
lapsed); and the Company shall not have given notice to the Purchaser of its
intent to terminate the Collaboration Agreement.

          (f) Representations and Warranties. The representations and warranties
made by the Company in this Agreement shall have been true and correct in all
material respects at the date hereof and as of the Closing with the same force
and effect as though all such representations and warranties had been made as of
the Closing.

          (g) No Injunctions. No provision of any applicable law, rule or
regulation and no judgment, order, decree or injunction shall prohibit the
consummation of the Closing.

          (h) Listing. The shares of Common Stock sold in the IPO shall be
listed on the New York Stock Exchange ("NYSE") or traded on the Nasdaq National
Market.

          (i) Closing of IPO. The Closing hereunder shall be concurrent with the
closing of the IPO.

     4.2 Conditions of the Company's Obligation. The obligation of the Company
to sell the Shares at the Closing is subject to the satisfaction of the
following conditions:

          (a) Performance. The Purchaser shall have performed and complied with
in all material respects all agreements, obligations and conditions contained in
this Agreement that are required to be performed or complied with by it on or
before the Closing.

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          (b) Consents, Waivers, Etc. Any waiting period applicable to this
Agreement and the Collaboration Agreement under the HSR Act (or any other
applicable Competition Laws) shall have expired or terminated early.

          (c) Rights Agreement Amendment. The Rights Agreement Amendment shall
have been executed by the Purchaser.

          (d) Collaboration Agreement. The Collaboration Agreement shall have
been duly authorized, executed and delivered by the Purchaser and constitute a
valid and binding obligation of the Purchaser, enforceable in accordance with
its terms, subject to laws of general application relating to bankruptcy,
insolvency and the relief of debtors and rules of law governing specific
performance, injunctive relief or other equitable remedies. The Company shall
not have the right to terminate the Collaboration Agreement for cause pursuant
to Section 9.5 thereof (provided, however, if the Company's right to so
terminate the Collaboration Agreement for cause is solely dependent on the
lapsing on any applicable "cure" period pursuant to Section 9.5 thereof, solely
for purposes of this Section 4.2(d), the Company shall be deemed to have the
right to terminate the Collaboration Agreement for cause notwithstanding the
failure of any such cure period to have lapsed; and the Purchaser shall not have
given notice to the Company of its intent to terminate the Collaboration
Agreement.

          (e) Representations and Warranties. The representations and warranties
made by the Purchaser in this Agreement shall have been true and correct in all
material respects at the date hereof and as of the Closing with the same force
and effect as though all such representations and warranties had been made as of
the Closing.

          (f) No Injunctions; Applicable Law. No provision of any applicable
law, rule or regulation and no judgment, order, decree or injunction shall
prohibit the consummation of the Closing nor shall the Closing result in any
violation of any such law, rule, regulation, judgment, order, decree or
injunction.

          (g) Listing. The shares of Common Stock sold in the IPO shall be
listed on the NYSE or traded on the Nasdaq National Market.

          (h) Closing of IPO. The Closing hereunder shall be concurrent with the
closing of the IPO.

          (i) Securities Regulations. The sale of the Shares to Purchaser shall
not be prohibited under state and federal securities laws and regulations.

                                    ARTICLE V

                              STANDSTILL AGREEMENT

     5.1. Definitions. For the purposes of this Agreement, the following words
and phrases shall have the following meanings:

          (i) "Actual Voting Power" means, as of the date of determination, the
total number of votes attaching to the outstanding securities entitled to vote
for the election of directors of the Company.

          (ii) "Affiliate" shall have the meaning given it in Rule 12b-2 under
the Securities Exchange Act of 1934, as amended (the "Exchange Act").

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          (iii) "Beneficial Ownership" "Beneficial Owner" and "Beneficially Own"
shall have the meanings described to those terms in Rule 13d-1 under the
Exchange Act.

          (iv) "Change of Control" means (1) the acquisition by a Third Party of
more than 50% of the Company's then outstanding Voting Securities or (2) the
consummation of a merger, acquisition, consolidation or reorganization or series
of such related transactions involving the Company, unless immediately after
such transaction or transactions, the Beneficial Owners of the Company
immediately prior to the first such transaction shall Beneficially Own at least
50% of the outstanding Voting Securities of the Company (or, if the Company
would not be the surviving company in such merger, consolidation or
reorganization, the Voting Securities of the surviving corporation issued in
such transaction or transactions in respect of Voting Securities of the Company
shall represent at least 50% of the Voting Securities of such surviving
company).

          (v) "Investor Group" means Purchaser and any member of a 13D Group to
which the Purchaser belongs.

          (vi) "Person" means an individual, corporation, partnership,
association, trust, unincorporated organization or other entity

          (vii) "13D Group" means any group of persons formed for the purpose of
acquiring, holding, voting or disposing of Voting Securities which would be
required under the Exchange Act and the rules and regulations promulgated
thereunder, to file a statement on Schedule 13D with the Securities and Exchange
Commission as a "person" within the meaning of Section 13(d)(3) of the Exchange
Act if such group beneficially owned sufficient securities to require such a
filing under the Exchange Act.

          (viii) "Standstill Period" shall mean the period beginning on the
Closing of the IPO and ending on the date that is one year following the Closing
of the IPO.

          (ix) "Threshold Percentage" means the percentage of Actual Voting
Power owned by the Purchaser immediately following the closing of the IPO and
the sale of Shares hereunder, which in no case shall exceed nineteen and
nine-tenths percent (19.9%) of Actual Voting Power.

          (x) "Third Party" means any Person or two or more Persons acting in
concert, other than the Purchaser and its Affiliates or the Company and its
Affiliates.

          (xii) "Voting Security" means, as of the date of determination, the
Common Stock of the Company, any other security generally entitled to vote for
the election of directors and any outstanding convertible securities, options,
warrants or other rights which are convertible into or exchangeable or
exercisable for securities entitled to vote for the election of directors.

     5.2. Standstill Obligations.

          (a) Limitation. At any time during the Standstill Period, except with
the prior written consent of the Company's Board of Directors, no member of the
Investor Group shall, directly or indirectly:

               (i) acquire any Voting Securities (except by way of stock splits,
stock dividends or other distributions) if the effect of such acquisition or
exercise would be to increase the percentage interest of the Investor Group in
the Actual Voting Power to more than the Threshold Percentage; or

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               (ii) publicly propose (on behalf of itself or to or with a Third
Party) any merger, business combination, restructuring, recapitalization or
similar transaction involving the Company or its subsidiaries or the purchase,
sale or other disposition outside the ordinary course of business of any
material portion of the assets of the Company or any of its subsidiaries.

          (b) Repurchases. Notwithstanding Section 5.2(a), no member of the
Investor Group shall be obligated to dispose of any Voting Securities if the
aggregate percentage ownership of the Investor Group is increased as a result of
a repurchase of Voting Securities by the Company.

          (c) Participation. Except with the prior written consent of the
Company's Board of Directors, during the Standstill Period the Investor Group
will not:

               (i) solicit proxies (or powers of attorney or similar rights to
vote) in respect of any Voting Securities;

               (ii) become a "participant" or "participant in a solicitation",
as those terms are defined in Regulation 14A of the General Rules and
Regulations promulgated pursuant to the Exchange Act, in opposition to a
solicitation by the Company; provided, however, that the Investor Group shall
not be deemed to be a "participant" or to have become engaged in a solicitation
hereunder solely by reason of the Company's solicitation of proxies in
connection with any meeting of the stockholders of the Company;

               (iii) seek to advise or intentionally influence any person or
entity with respect to the voting of Voting Securities in connection with any
such solicitation, in opposition to the recommendation of a majority of the
Board of Directors with respect to any matter relating to a Change of Control;

               (iv) initiate, propose or otherwise solicit stockholders for the
approval of any stockholder proposal (as described in Rule 14a-8 under the
Exchange Act or otherwise) with respect to the Company that is opposed by the
Board of Directors;

               (v) form or join any 13D Group for the purpose of voting,
purchasing or disposing of Voting Securities or the acquisition of all or
substantially all of assets of the Company;

               (vi) deposit any Voting Securities in a voting trust or subject
them to a voting agreement or other arrangement of similar effect, except in
order to comply with Competition Laws or other legal requirements;

               (vii) otherwise act, alone or in concert with others, in a manner
designed or having the deliberate effect of circumventing the restrictions
otherwise imposed hereunder, publicly announce any intention, plan or
arrangement inconsistent with the foregoing or finance or agree to finance any
other person in connection with any of the activities prohibited by this
Agreement; or

               (viii) publicly request, propose or otherwise seek any amendment
or waiver of the provisions of this Article 5.

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     5.3 Exceptions. The limitations provided in Section 5.2 shall immediately
terminate upon the occurrence of any of the following events:

          (a) the commencement by any Person (other than a member of the
Investor Group or an Affiliate thereof) of a bona fide tender or exchange offer
seeking to acquire Beneficial Ownership of fifty percent (50%) or more of the
outstanding shares of Voting Securities of the Company;

          (b) the execution of an agreement by the Company and any Person which,
if consummated, would result in either (i) a Change of Control of the Company or
(ii) the sale of all or substantially all of the Company's assets; or

          (c) the adoption by the Company of a plan of liquidation or
dissolution with respect to the Company.

     5.4 Exclusion. No action or actions taken by the Purchaser pursuant to the
terms of the Collaboration Agreement or in connection with exercising or
enforcing its rights thereunder shall be deemed to violate the restrictions in
Section 5.2.

                                   ARTICLE VI

                                 MISCELLANEOUS

     6.1 No Waiver. No failure or delay on the part of any party to this
Agreement in exercising any right, power or remedy hereunder shall operate as a
waiver thereof; nor shall any single or partial exercise of any such right,
power or remedy preclude any other or further exercise thereof or the exercise
of any other right, power or remedy hereunder. None of the terms, covenants and
conditions of this Agreement can be waived except by the written consent of the
party waiving compliance.

     6.2 Publicity. The parties may, subject to compliance with the Securities
Act, issue a joint press release announcing this Agreement and the transactions
contemplated hereby following execution of this Agreement. Any proposed
announcement, press release or other public disclosure concerning this Agreement
and/or any of the transactions or relationships contemplated hereby shall be
mutually approved by both parties (which approval shall not be unreasonably
withheld); provided, however, that the restrictions contained in this Section
6.2 do not apply to disclosures required by law, the rules of the NYSE, the NASD
or under U.S. generally accepted accounting principles. The Purchaser agrees and
acknowledges that this Agreement and the transactions contemplated hereby shall
be disclosed in, and filed as an exhibit to, the Registration Statement.

     6.3 Amendments, Waivers and Consents. Any provision in this Agreement to
the contrary notwithstanding, and except as hereinafter provided, changes in or
additions to this Agreement may be made, and compliance with any covenant or
provision set forth herein may be omitted or waived, if the party requesting
such change, addition, omission or waiver shall obtain consent thereto in
writing from the other party. Any waiver or consent may be given subject to
satisfaction of conditions stated therein and any waiver or consent shall be
effective only in the specific instance and for the specific purpose for which
given. Any such amendment or waiver or consent effected in accordance with this
Section 6.3 shall be binding upon the parties and their respective successors
and assigns.

     6.4 Addresses for Notices. Any notice required or permitted by this
Agreement shall be in writing and shall be deemed sufficient upon receipt, when
delivered personally or by courier, overnight delivery service or confirmed
facsimile, or seventy-two (72) hours after being deposited in the regular

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mail as certified or registered mail (airmail if sent internationally) with
postage prepaid, if such notice is addressed to the party to be notified at such
party's address or facsimile number as set forth below, or as subsequently
modified by written notice.

     If to the Company:

          Trubion Pharmaceuticals, Inc.
          2401 Fourth Avenue, Suite 1050
          Seattle, WA 98121
          Attn: Chief Executive Officer and General Counsel
          Facsimile Number: (206) 838-0503

     If to the Purchaser:

          Wyeth Pharmaceuticals
          500 Arcola Road
          Collegeville, Pennsylvania 19426
          Attn: Senior Vice President, Corporate Business Development
          Fax: (484) 865-6476

          with a copy to:

          Wyeth
          5 Giralda Farms
          Madison, NJ 07940
          Attn: Executive Vice President and General Counsel
          Facsimile: (973) 660-7156

     6.5 Binding Effect; Assignment. This Agreement may not be assigned by
either party without the prior written consent of the other; provided, however,
that the Purchaser may assign its rights and delegate its duties hereunder to an
Affiliate without the prior written consent of the Company; provided, however,
Purchaser shall remain subject to Section 5 hereof regardless of any such
assignment; and provided further that if the Company undergoes a Change of
Control in which (a) the Company is not the surviving entity and (b) this
Agreement does not terminate pursuant to Section 1.5(b) in connection with such
Change of Control, the surviving entity and the Purchaser shall enter into a
replacement agreement with substantially the same terms as this Agreement.
Subject to the foregoing, the terms and conditions of this Agreement shall inure
to the benefit of and be binding upon the respective successors and assigns of
the parties. Nothing in this Agreement, express or implied, is intended to
confer upon any party other than the parties hereto or their respective
successors and assigns any rights, remedies, obligations, or liabilities under
or by reason of this Agreement, except as expressly provided in this Agreement.

     6.6 Entire Agreement. This Agreement and the documents referred to herein
constitute the entire agreement between the parties and supersede any prior
understandings or agreements concerning the subject matter hereof.

     6.7 Specific Performance. The parties acknowledge and agree that
irreparable damage would occur in the event any of the provisions of Article V
of this Agreement were not performed in accordance with their specific terms or
were otherwise breached. Accordingly, it is agreed that the parties shall be
entitled to an injunction or injunctions to prevent or cure breaches of the
provisions of Article V of this

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Agreement and to enforce specifically the terms and provisions of such Article
in any court of the United States or any state thereof having jurisdiction, in
addition to any other remedy to which they may be entitled in law or in equity.

     6.8 Severability. The provisions of this Agreement are severable and, in
the event that any court of competent jurisdiction shall determine that any one
or more of the provisions or part of a provision contained in this Agreement
shall, for any reason, be held to be invalid, illegal or unenforceable in any
respect, such invalidity, illegality or unenforceability shall not affect any
other provision or part of a provision of this Agreement; but this Agreement,
shall be reformed and construed as if such invalid or illegal or unenforceable
provision, or part of a provision, had never been contained herein, and such
provisions or part reformed so that it would be valid, legal and enforceable to
the maximum extent possible.

     6.9 Governing Law. This Agreement shall be governed by, and construed and
enforced in accordance with, the laws of the State of Delaware without reference
to Delaware conflicts of law provisions.

     6.10 Headings. Article, Section and subsection headings in this Agreement
are included herein for convenience of reference only and shall not constitute a
part of this Agreement for any other purpose.

     6.11 Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be enforceable against the party actually
executing the counterpart, and all of which together shall constitute one
instrument.

                            [Signature page follows.]

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                                                                  EXECUTION COPY

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as of the date first above written.

                                        TRUBION PHARMACEUTICALS, INC.

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------

                                        WYETH

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------

<PAGE>

                                                                  EXECUTION COPY

                                                                       EXHIBIT A

                    MATTERS TO BE COVERED BY COMPANY COUNSEL

     1. The Company is a corporation validly existing under Delaware law and in
good standing with the Secretary of the State of Delaware and has the corporate
power to execute and deliver the Agreement and to perform its obligations
thereunder.

     2. The Company has duly authorized, executed and delivered the Agreement,
and the Agreement constitutes the Company's valid and binding agreement
enforceable against the Company in accordance with its terms, except as
enforceability may be limited by bankruptcy, insolvency, reorganization,
moratorium or similar laws relating to or affecting creditors' rights generally
or by general equitable principles.

     3. No consent, approval, authorization or order of, or any filing or
declaration with, any court or governmental agency or body is required in
connection with the execution, delivery and performance of the Agreement by the
Company or in connection with the taking by the Company of any action
contemplated thereby, other than as indicated in the Agreement or such as have
been obtained and made and such as may be required under federal and state
securities laws.

     4. The execution, delivery and performance of the Agreement by the Company,
and the consummation by the Company of the transactions contemplated therein do
not and will not (a) violate the Certificate of Incorporation or By-Laws of the
Company, (b) materially violate any judgment, ruling, decree or order known to
such counsel, (c) materially violate any statute or regulation applicable to the
business or properties of the Company, or (d) result in a material breach or
violation of any of the terms or provisions of, or constitute a default or
result in the acceleration of any obligation under any material contract to
which the Company is a party or bound.

     5. The Shares delivered on the date hereof have been duly authorized and
validly issued and are fully paid and non-assessable shares of the Company.

<PAGE>

                                                                  EXECUTION COPY

                                  EXHIBIT 5.2B

                          TRUBION PHARMACEUTICALS, INC.

                               AMENDMENT NO. 1 TO

                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

     This Amendment No. 1 to the Amended and Restated Investor Rights Agreement
(the "RIGHTS AGREEMENT") dated as of July 13, 2004 is entered into as of
________, 2005, by and among Trubion Pharmaceuticals, Inc., a Delaware
corporation (the "COMPANY"), Wyeth, a Delaware corporation ("WYETH"), and the
investors set forth on EXHIBIT A hereto (collectively the "INVESTORS" and each
individually an "INVESTOR").

                                    RECITALS

     A. The Company and the Investors are parties to the Rights Agreement.

     B. The Company and Wyeth have entered into a Common Stock Purchase
Agreement dated as of December __, 2005 (the "PURCHASE AGREEMENT") pursuant to
which the Company will sell to Purchaser and Purchaser will purchase from the
Company shares of the Company's Common Stock concurrent with and conditioned
upon the closing of the Company's initial public offering (the "CLOSING"). A
condition to the Purchaser's obligations under the Purchase Agreement is that
the Rights Agreement be amended in order to provide Purchaser with certain
rights to register shares of the Company's Common Stock.

     C. Pursuant to Section 6.5 of the Rights Agreement, the written consent of
the Company and the Investors holding a majority of the Registrable Securities
(the "REQUISITE HOLDERS") is required to amend the Rights Agreement.

     D. The Company and the Requisite Holders desire to induce Purchaser to
enter into the Purchase Agreement by agreeing to the terms and conditions set
forth herein.

     NOW, THEREFORE, in consideration of the mutual promises, representations,
warranties, covenants and conditions set forth in this Agreement, the parties
hereto agree as follows:

     1. Definitions. Capitalized terms used herein without definition shall have
the meaning ascribed to them in the Rights Agreement.

     2. Addition of Purchaser as a Party to the Rights Agreement. Effective upon
the Closing pursuant to the Purchase Agreement, the parties hereby agree to add
Purchaser as a party to the Rights Agreement and Purchaser shall be deemed a
"Holder" of Registrable Securities for purposes of Sections 1, 2 and 6 of the
Rights Agreement and subject to all of the rights and obligations of such
Sections. For purposes of clarification, Purchaser shall not be entitled to the
rights or subject to the obligations set forth in Sections 3, 4 and 5 of the
Rights Agreement and Purchaser shall not be deemed an "INVESTOR" for purposes of
the Rights Agreement.

<PAGE>

                                                                   REDACTED COPY

     3. Amendment to Section 1.1. The definition of "Registrable Securities" set
forth in Section 1.1 is hereby amended and restated to read in its entirety as
follows:

          "REGISTRABLE SECURITIES" means (a) Common Stock of the Company issued
or issuable upon conversion of the Shares, (b) Common Stock of the Company
issued to Frazier Healthcare Fund ("FRAZIER"), ARCH Venture Fund ("ARCH") and
Scott Minick ("MINICK") pursuant to those certain Common Stock Purchase
Agreements dated November 19, 2002 by and between the Company and each of
Frazier, Arch and Minick, (c) Common Stock of the Company issued to Wyeth
pursuant to the Purchase Agreement, and (d) any Common Stock of the Company
issued as (or issuable upon the conversion or exercise of any warrant, right or
other security which is issued as) a dividend or other distribution with respect
to, or in exchange for or in replacement of, the securities described in (a),
(b) and (c) above; provided, however, the shares referred to in clause (c) above
shall not qualify as Registrable Securities for the purposes of Sections 2.2
hereof until the 15 month anniversary of the Closing. For the avoidance of
doubt, in the event that the Company effects a registration under the Securities
Act pursuant to Section 2.2 hereof prior to the 15 month anniversary of the
Closing, in connection with such registration the Shares referred to in clause
(c) above shall qualify as Registrable Securities for the purposes of Section
2.3. Notwithstanding the foregoing, Registrable Securities shall not include any
securities sold by a person to the public pursuant to a registration statement
or Rule 144 or sold in a private transaction in which the transferor's rights
under SECTION 2 of this Agreement are not assigned.

     4. Amendment to Section 2.1(a)(ii). Section 2.1(a)(ii) is amended effective
immediately following the expiration of the "Market Stand-Off" period set forth
in Section 2.12 hereof, by deleting the last sentence thereof and substituting
therefor the following:

     "Subject to the other terms of this Agreement (including without limitation
     the restrictions on assignment of registration rights set forth in Section
     2.10 and Sections 2.1(b) and (d)), it is agreed that the restrictions
     contained in this Section 2.1(a)(ii) shall not apply to dispositions of
     Shares or Registrable Securities made pursuant to Rule 144 promulgated
     under the Securities Act."

     5. Amendment to Section 6.5. Section 6.5 is hereby amended by adding, after
the final sentence thereof, the following:

          Notwithstanding the foregoing, neither this Agreement nor any term
hereof may be amended, waived, discharged or terminated in any way that
diminishes or eliminates the rights particular to Wyeth hereunder and in a
manner different than the other holders of Registrable Securities, such action
shall require the prior written consent of Wyeth.

     6. Waiver of Right of Participation. Each Investor on behalf of itself and
all other Investors and holders of Registrable Securities hereby waives any
right of participation set forth in Section IV of the Rights Agreement with
respect to the sale and issuance of the shares of Company Common Stock to Wyeth
pursuant to the Purchase Agreement.

     7. No Other Amendments. Except as expressly amended or waived as set forth
above, the Rights Agreement shall remain in full force and effect in accordance
with its terms.

     8. Counterparts. This Amendment may be executed in any number of
counterparts, each of which shall be deemed an original and all of which
together shall constitute one document.

                                       -2-

<PAGE>

                                                                   REDACTED COPY

                            [Signature pages follow.]

                                       -3-

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "COMPANY"

                                        TRUBION PHARMACEUTICALS, INC.
                                        a Delaware corporation

                                        By:
                                            ------------------------------------
                                            Peter Thompson, M.D., FACP
                                            President and Chief Executive
                                            Officer

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "WYETH"

                                        WYETH

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        PROSPECT VENTURE PARTNERS II, L.P.

                                        By: Prospect Management Co. II, LLC
                                        Its General Partner

                                        By:
                                            ------------------------------------
                                        Name: David Schnell
                                        Title: Managing Member

                                        PROSPECT ASSOCIATES II, L.P.

                                        By: Prospect Management Co. II, LLC
                                        Its General Partner

                                        By:
                                            ------------------------------------
                                        Name: David Schnell
                                        Title: Managing Member

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        VENROCK PARTNERS, L.P.
                                           by its General Partner, Venrock
                                           Partners Management, LLC

                                        VENROCK ASSOCIATES IV, L.P.
                                           by its General Partner, Venrock
                                           Management IV, LLC

                                        VENROCK ENTREPRENEURS FUND IV, L.P.
                                           by its General Partner, VEF
                                           Management IV, LLC

                                        By:
                                           -------------------------------------
                                        Name: Anders D. Hove
                                        Title: Member
                                        Address: 30 Rockefeller Plaza
                                                 Room 5508
                                                 New York, NY 10112

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT
<PAGE>

                                                                   REDACTED COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        ARCH VENTURE FUND V, L.P.

                                        By: ARCH Venture Partners V, L.P.
                                            Its general partner

                                        By: ARCH Venture Partners V, L.L.C.
                                            Its general partner

                                        By:
                                            ------------------------------------
                                        Title: Managing Director

                                        ARCH V ENTREPRENEURS FUND, L.P.

                                        By: ARCH Venture Partners V, L.P.
                                            Its general partner

                                        By: ARCH Venture Partners V, L.L.C.
                                            Its general partner

                                        By:
                                            ------------------------------------
                                        Title: Managing Director

                                        HEALTHCARE FOCUS FUND, L.P.

                                        By: ARCH Venture Partners V, L.P.
                                            Its general partner

                                        By: ARCH Venture Partners V, L.L.C.
                                            Its general partner

                                        By:
                                            ------------------------------------
                                        Title: Managing Director

                                        8

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        OXFORD BIOSCIENCE PARTNERS IV L.P.

                                        By: OBP Management IV L.P.

                                        By:
                                            ------------------------------------
                                            Mark P. Carthy - General Partner

                                        MRNA FUND II L.P.

                                        By: OBP Management IV L.P.

                                        By:
                                            ------------------------------------
                                            Mark P. Carthy - General Partner

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        FRAZIER HEALTHCARE IV, L.P.
                                        By FHM IV, LP, its general partner
                                        By FHM IV, LLC, its general partner

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                                        FRAZIER AFFILIATES IV, L.P.
                                        By FHM IV, LP, its general partner
                                        By FHM IV, LLC, its general partner

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                                        FRAZIER HEALTHCARE III, L.P.
                                        By FHM III, LLC

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                                        FRAZIER AFFILIATES III, L.P.
                                        By FHM III, LLC

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        ATP CAPITAL, L.P.

                                        By: ATP General Partner LLC
                                            Its General Partner

                                        By:
                                            ------------------------------------
                                            Jonathan Malkin, Manager

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                   REDACTED COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        CASCADE INVESTMENTS, L.L.C.

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                                        2

<PAGE>

                                                                  EXECUTION COPY

IN WITNESS WHEREOF, the parties hereto have executed this AMENDMENT NO. 1 TO THE
RIGHTS AGREEMENT as of the date set forth in the first paragraph hereof.

                                        "INVESTOR"

                                        ----------------------------------------

                                        By:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Its:
                                             -----------------------------------

                      SIGNATURE PAGE TO AMENDMENT NO. 1 TO
                 AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

<PAGE>

                                                                  EXECUTION COPY

                                   EXHIBIT 5.3
                       ADDITIONAL RESEARCH AND DEVELOPMENT
                                EXPENSE PAYMENTS

A. ADDITIONAL RESEARCH AND DEVELOPMENT EXPENSE PAYMENTS FOR CD20 PRODUCTS

Within *** after Trubion's or Wyeth's achievement of the following events with
respect to any *** (each payable one time only even if achieved with respect to
more than one ***), Wyeth shall make the following payments to Trubion:

***

B. ADDITIONAL RESEARCH AND DEVELOPMENT EXPENSE PAYMENTS FOR ***

Within *** after Wyeth's achievement of the following events with respect to any
*** (each payable one time only even if completed or achieved with respect to
more than one ***), Wyeth shall make the following payments to Trubion:

***

C. ADDITIONAL RESEARCH AND DEVELOPMENT EXPENSE PAYMENTS FOR OTHER PRODUCTS

Within *** after Wyeth's achievement of the following events with respect to
each Other Product (up to a maximum of *** Other Products), Wyeth shall make the
following payments to Trubion; provided, however, that: (i) in the event that
any of the following events is achieved with respect to two or more Other
Products that are directed against the same Wyeth Target, such payment shall be
payable only with respect to the first such Other Product for which the event
occurred; and (ii) in the event that an Other Product is directed against two or
more Wyeth Targets, such Licensed Product shall be a Multispecific SMIP Product,
the consequences of which are as described in Section D below:

***

D. NO ADDITIONAL PAYMENTS; OTHER APPLICABLE TERMS AND CONDITIONS

(i) Other than the payments listed in Sections A - C of this Exhibit 5.3, no
Additional Research and Development Expense Payments shall be due or payable by
Wyeth to Trubion for any Licensed Product, regardless of the number of Licensed
Products Developed against any Trubion Target or Wyeth Target.

(ii) Each of the Additional Research and Development Expense Payments set forth
above shall be payable one time only with respect to each Licensed Target
(regardless

                                        2

<PAGE>

                                                                   REDACTED COPY

of the number of times the specified event is achieved with respect
to any Licensed Product(s)).

(iii) In the event that the Development of a Licensed Product directed against a
particular Licensed Target hereunder (an "Initial Licensed Product") is
discontinued prior to the Commercialization of such Initial Licensed Product,
and Development has been initiated with respect to another Licensed Product
directed against such Licensed Target (a "Replacement Licensed Product"),
payments with respect to such Replacement Licensed Product shall be due under
this Exhibit 5.3 only upon the achievement of those events that have not been
achieved by the Initial Licensed Product.

(iv) Without limiting the foregoing, if a specified event listed in Sections A -
C of this Exhibit 5.3 occurs with respect to a Licensed Product directed against
two or more Licensed Targets (a "Multispecific SMIP Product"), then (a) no more
than one Additional Research and Development Expense Payment shall become
payable with respect to the achievement of such event for such Multispecific
SMIP Product, (b) only the highest Additional Research and Development Expense
Payment based on the achievement of such event that has not already become
payable shall be payable, and (c) if all Additional Research and Development
Expense Payments based on the achievement of such event have already become
payable, then no payment shall be due with respect to such event for such
Multispecific SMIP Product. By way of example only, if a BLA filing and
acceptance for review in the U.S. occurs with respect to a Multispecific SMIP
Product directed against the *** and a Wyeth Target ("Wyeth Target Q"), then:
(x) if the *** Additional Research and Development Expense Payment under Section
B for such event has not already become payable, only such $15.0 million amount
shall become payable; (y) if such *** Additional Research and Development
Expense Payment had already become payable, then the *** Additional Research and
Development Expense Payment under Section C for such event shall become payable,
if it has not previously become payable; and, (z) if both such *** and such ***
Additional Research and Development Expense Payment had previously become
payable, then no payment shall be due upon BLA filing and acceptance for review
in the U.S. with respect to such Multispecific SMIP Product. To continue the
same example, if the same Multispecific SMIP Product meets the condition set
forth in (x) above, and thereafter a BLA filing and acceptance for review in the
U.S. occurs with respect to a separate Licensed Product directed only against
such Wyeth Target Q, then upon such subsequent occurrence by such separate
Licensed Product, the *** Additional Research and Development Expense Payment
shall be payable with respect to such Wyeth Target Q (if such *** payment had
not previously become payable in connection with Wyeth Target Q).

(v) Subject to the limitations set forth above in Sections A, B and C and in
this Section D, if an Additional Research and Development Expense Payment based
on a clinical study of, or Regulatory Approval filing for, a Licensed Product
for a particular indication (a "Later Development Event") becomes payable before
the achievement of an earlier phase clinical study event with respect to such
Licensed

                                        3

<PAGE>

                                                                   REDACTED COPY

Product for the same indication for which Additional Research and Development
Expense Payments would have been payable (an "Earlier Development Event"), then
the Additional Research and Development Expense Payment for the Earlier
Development Event also shall become payable upon occurrence of the Later
Development Event. ***

                                        4

<PAGE>

                                                                  EXECUTION COPY

                                 EXHIBIT 8.2(D)
                               THIRD PARTY RIGHTS

                           [INTENTIONALLY LEFT BLANK]

<PAGE>

                                                                  EXECUTION COPY

                                 EXHIBIT 8.2(E)
                          GOVERNMENT FUNDING AGREEMENTS

                            NIH GRANT # 5 R01 CA90143

          PROJECT TITLE: GENE THERAPY WITH MAB DERIVATIVES EXPRESSED ON
                                     TUMORS
<PAGE>

CONFIDENTIAL

                                    APPENDIX

                                  WYETH TARGETS

<TABLE>
<CAPTION>
                                       GENBANK NUCLEOTIDE    GENBANK PROTEIN
TARGET #   TARGET NAME   GENE SYMBOL    ACCESSION NUMBER    ACCESSION NUMBER
--------   -----------   -----------   ------------------   ----------------
<S>        <C>           <C>           <C>                  <C>
   ***         ***           ***               ***                 ***
</TABLE><PAGE>

                                                                   EXHIBIT 10.13

                          DEVELOPMENT AND MANUFACTURING

                                SERVICE AGREEMENT

                                     BETWEEN

                               LONZA BIOLOGICS PLC

                                       AND

                          TRUBION PHARMACEUTICALS, INC.

                                                          CONFIDENTIAL TREATMENT

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
1.  Definitions..........................................................     3

2.  Customer Obligations, Warranties and Indemnities.....................    10

3.  Provision of the Services............................................    12

4.  Quality; Project Management..........................................    15

5.  Delivery, Transportation of Product and Customer Tests...............    17

6.  Price and Terms of Payment...........................................    18

7.  LB Warranties and Covenants and Indemnity............................    18

8.  Confidentiality and Non-Use..........................................    21

9.  Termination; Ownership; License Rights...............................    23

10. Force Majeure........................................................    28

11. Governing Law, Jurisdiction and Enforceability; Dispute Resolution...    28

12. Notices..............................................................    29

13. Miscellaneous........................................................    30

14. Limitation of Liability; Exclusion of Certain Damages................    31
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        2

<PAGE>

     THIS AGREEMENT is made effective as of the 8th day of January 2004 (the
"Effective Date") BETWEEN

     1. LONZA BIOLOGICS PLC, the registered office of which is at 228 Bath Road,
Slough, Berkshire SL1 4DX, England (herein after referred to as "LB"), and

     2. TRUBION PHARMACEUTICALS, INC., (formerly known as GENECRAFT, INC.) of
24014th Avenue, Suite 1050, Seattle, WA 98121, USA (herein after referred to as
the "Customer").

     WHEREAS

     A. The Customer has created or controls certain Cell Lines as defined
herein; and

     B. LB has expertise in the evaluation and production of proteins for
therapeutic use using such Cell Lines; and

     C. The Customer wishes to contract LB for Services as defined herein
relating to the Cell Line as described in the Agreement; and

     D. LB is prepared to perform such Services for the Customer under the terms
and conditions set out herein.

     NOW IT IS AGREED AS FOLLOWS:

     1.   DEFINITIONS. The following terms shall have the following meanings:

<TABLE>
<S>                                          <C>
     "Affiliate"                             means any company, partnership or
                                             other entity which directly or
                                             indirectly Controls, is Controlled
                                             by or is under common Control with
                                             the relevant party to this
                                             Agreement. "Control" means the
                                             ownership of more than fifty per
                                             cent (50%) of the issued share
                                             capital or the legal power to
                                             direct or cause the direction of
                                             the general management and policies
                                             of the party in question.

     "Agreement"                             means this agreement, including and
                                             incorporating Schedule 1
                                             (Definitions and Specifications),
                                             Schedule 2 (Services), Schedule 3
                                             (Price and Terms of Payment),
                                             Schedule 4 (Quality Agreement), and
                                             Schedule 5 (Commercial Terms for
                                             Technology Transfer), all as the
                                             same may be amended or varied from
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        3

<PAGE>

<TABLE>
<S>                                          <C>
                                             time to time by written agreement
                                             of the parties.

     "August 2003 Services Agreement"        means that certain development and
                                             manufacturing agreement dated 12
                                             August 2003 between the parties for
                                             the development and manufacture of
                                             the Product, as amended or varied
                                             from time to time by written
                                             agreement of the parties.

     "Batch"                                 means the total quantity of
                                             Manufactured Product obtained from
                                             one fermentation and associated
                                             purification run using the Process.

     "Cell Line"                             means the cell line provided by
                                             Customer to LB, the particulars of
                                             which are set out in Schedule 1.

     "cGMP"                                  means the regulatory requirements
                                             for current Good Manufacturing
                                             Practices and General Biologics
                                             Products Standards as promulgated
                                             by the United States Food and Drug
                                             Administration ("FDA") (or any
                                             successor agency thereto) under the
                                             United States Federal Food Drug and
                                             Cosmetic Act and the Public Health
                                             Service Act, at 21 CFR (Parts 210,
                                             211, 600 and 610), and the Guide to
                                             Good Manufacturing Practices for
                                             Medicinal Products as promulgated
                                             under European Directive
                                             91/356/EEC, all as the same may be
                                             amended from time to time.

     "cGMP Product"                          means Product which is required
                                             under Schedule 2 to be manufactured
                                             in accordance with cGMP.

     "Certificate of Analysis"               means, for each Batch, a document
                                             in a format agreed to by the
                                             parties and prepared by LB listing
                                             (a) the date of manufacturing,
                                             unique Batch number, tests
                                             performed, Specifications, test
                                             dates, and test results, (b) the
                                             quantity of Manufactured Product in
                                             such Batch, and certifying that
                                             such Batch was manufactured in
                                             accordance with the Specifications
                                             and cGMP, and (c) the tests
                                             performed by LB or permitted
                                             Testing Laboratories,
                                             Specifications, and test results;
                                             all with respect to such particular
                                             Batch
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        4

<PAGE>

<TABLE>
<S>                                          <C>
                                             and as required by the
                                             Specifications, the accuracy of
                                             which has been certified by LB.

     "Critical Raw Materials"                has the meaning given to it in
                                             Clause 4.6 below.

     "Customer"                              means Trubion Pharmaceuticals,
                                             Inc., and its successors in title
                                             and lawful assigns.

     "Customer Information"                  means (a) all Customer Know-How and
                                             other tangible and intangible data,
                                             information, and know-how, whether
                                             in written, printed, graphic,
                                             electronic, or oral form, supplied
                                             by or on behalf of Customer to LB
                                             hereunder or under the August 2003
                                             Services Agreement; (b) all
                                             Documentation and all tangible and
                                             intangible data, information,
                                             know-how, and Intellectual Property
                                             included in the Documentation; (c)
                                             all Deliverables and all tangible
                                             and intangible data, information,
                                             know-how, and Intellectual Property
                                             included in the Deliverables; and
                                             (d) all tangible and intangible
                                             data, information, know-how, and
                                             Intellectual Property included in
                                             the Customer Process; "Customer
                                             Information" does not include LB
                                             Know-How, the LB Patent Rights, the
                                             LB Process, the New General
                                             Application Intellectual Property,
                                             and LB's other Intellectual
                                             Property, "Customer Information" is
                                             a part of "Customer Technology."

     "Customer Know-How"                     means all know-how, technical and
                                             other information relating directly
                                             or indirectly to the Cell Line, the
                                             Customer Process (including for the
                                             avoidance of doubt improvements or
                                             modifications thereto from time to
                                             time, other than and excluding the
                                             LB Process and any New General
                                             Application Intellectual Property),
                                             Customer's business, technology,
                                             finances or operations, trade
                                             secrets, the Customer Materials,
                                             and/or the Product, known by
                                             Customer from time to time;
                                             "Customer Know-How" does not
                                             include LB Know-How, the LB Patent
                                             Rights the LB Process, the New
                                             General Application Intellectual
                                             Property, LB's other Intellectual
                                             Property, and information in the
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        5

<PAGE>

<TABLE>
<S>                                          <C>
                                             public domain; "Customer Know-How"
                                             is a part of "Customer
                                             Information."

     "Customer Materials"                    means the materials (if any)
                                             supplied by Customer to LB pursuant
                                             to this Agreement.

     "Customer Patent Rights"                means all patents and patent
                                             applications, together with any
                                             extensions, reissues,
                                             reexaminations, substitutions,
                                             renewals, divisions, continuations,
                                             and continuations-in-part thereof,
                                             of any kind throughout the world
                                             that are necessary or useful in
                                             performance of the Services, which
                                             from time to time Customer is the
                                             owner of or entitled to use, other
                                             than and excluding the LB Patent
                                             Rights.

     "Customer Process"                      means that portion of the Process
                                             not composed of or included within
                                             the LB Process, including without
                                             limitation all processes,
                                             procedures, protocols, know-how,
                                             technology, information and
                                             Intellectual Property developed by
                                             LB and/or Customer specifically
                                             with respect to manufacture of the
                                             Product under or as a result of
                                             this Agreement or the August 2003
                                             Services Agreement; "Customer
                                             Process" does not include LB
                                             Know-How, the LB Patent Rights, the
                                             LB Process, the New General
                                             Application Intellectual Property,
                                             or LB's other Intellectual
                                             Property.

     "Customer Technology"                   means all data, information,
                                             know-how, materials, and
                                             Intellectual Property which from
                                             time to time Customer is the owner
                                             of or entitled to use, including
                                             without limitation the Customer
                                             Know-How, the Customer Patent
                                             Rights, the Cell Line, the Customer
                                             Materials, the Customer
                                             Information, the Customer Process,
                                             the New Customer Intellectual
                                             Property, and the Product;
                                             "Customer Technology" does not
                                             include LB Know-How, the LB Patent
                                             Rights, the LB Process, the New
                                             General Application Intellectual
                                             Property, LB's other Intellectual
                                             Property, and information in the
                                             public domain.
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                       6

<PAGE>

<TABLE>
<S>                                          <C>
     "Deliver", "Delivered" or "Delivery"    has the meaning given to it in
                                             Clause 5.1 below,

     "Deliverables"                          means the data, information,
                                             material, reports, Documentation,
                                             Product, samples and other items
                                             that LB is obligated to provide to
                                             the Customer under the terms of the
                                             Services, as set forth in Schedule
                                             2.

     "Documentation"                         means all data, information and
                                             materials, whether in written,
                                             printed, graphic, or electronic
                                             form, resulting from the work
                                             conducted and/or results achieved
                                             in connection with the Services,
                                             including without limitation
                                             documents reasonably necessary for
                                             Customer to complete any regulatory
                                             filings for the Product;
                                             "Documentation" does not include LB
                                             Know-How, the LB Patent Rights, the
                                             LB Process, the New General
                                             Application Intellectual Property,
                                             and LB's other Intellectual
                                             Property; "Documentation" is a part
                                             of "Customer Information."

     "Intellectual Property"                 means proprietary methods,
                                             discoveries, inventions, patents,
                                             trade secrets, copyrights,
                                             trademarks, service marks, trade
                                             dress, compositions, products,
                                             procedures, know-how, data,
                                             reports, programs, processes,
                                             protocols, written or electronic
                                             writings, illustrations, images,
                                             and any other form of proprietary
                                             rights, and, as the context
                                             requires, includes, among other
                                             things, the Customer Know-How, the
                                             Customer Patent Rights, the
                                             Customer Process, the New Customer
                                             Intellectual Property, the LB
                                             Know-How, the LB Patent Rights, the
                                             LB Process and the New General
                                             Application Intellectual Property.

     "LB Know-How"                           means all know-how, technical and
                                             other information relating directly
                                             or indirectly to the LB Patent
                                             Rights, the LB Process (including
                                             for the avoidance of doubt
                                             improvements; or modifications
                                             thereto from time to time, other
                                             than and excluding the Customer
                                             Process and any New Customer
                                             Intellectual Property) LB's
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        7

<PAGE>

<TABLE>
<S>                                          <C>
                                             business, technology, finances or
                                             operations, and trade secrets known
                                             to LB from time to time; "LB
                                             Know-How" does not include the
                                             Customer Patent Rights, the
                                             Customer Know-How, the New Customer
                                             Intellectual Property, the Customer
                                             Process, Customer's other
                                             Intellectual Property, and
                                             information in the public domain.

     "LB Patent Rights"                      means all patents and patent
                                             applications, together with any
                                             extensions, reissues,
                                             reexaminations, substitutions,
                                             renewals, divisions, continuations,
                                             and continuations-in-part thereof,
                                             of any kind throughout the world
                                             relating to the LB Process which
                                             from time to time LB is the owner
                                             of or is entitled to use; "LB
                                             Patent Rights" does not include the
                                             Customer Patent Rights and the New
                                             Customer Intellectual Property and
                                             Customer's other Intellectual
                                             Property.

     "LB Process"                            means the manufacturing process for
                                             proteins that, as of the Effective
                                             Date, is included within the LB
                                             Patent Rights and LB Know-How,
                                             along with any New General
                                             Application Intellectual Property,
                                             as defined herein in Clause 9.8.2.

     "Legal Requirements"                    means any and all laws, rules,
                                             regulations, ordinances,
                                             guidelines, and standards of any
                                             international, national, state, or
                                             local governmental authority,
                                             applicable to LB, the Services, the
                                             Product, or any facility at which
                                             any of the Services are performed,
                                             including without limitation (a)
                                             cGMP, and (b) all laws and
                                             regulations requiring permits,
                                             licenses, filings and
                                             certifications with respect to LB,
                                             the Services, the Product, or any
                                             facility at which any of the
                                             Services are performed.

     "Manufactured Product"                  means any and all tangible forms of
                                             the Product which are manufactured
                                             under this Agreement using the
                                             Process, including without
                                             limitation all in-process
                                             intermediates, samples and
                                             derivatives thereof.
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        8

<PAGE>

<TABLE>
<S>                                          <C>
     "New Customer Intellectual Property"    has the meaning given to it in
                                             Clause 9.8.3.

     "New General Application Intellectual   has the meaning given to it in
     Property"                               Clause 9.8.2.

     "Price"                                 means the price specified in
                                             Schedule 3 for the Services.

     "Process"                               means the process for the
                                             production of the Product from the
                                             Cell Line pursuant to this
                                             Agreement, which is composed of the
                                             LB Process and the Customer
                                             Process, and including any
                                             improvements, changes or
                                             modifications to such process from
                                             time to time.

     "Product"                               means the proprietary Small Modular
                                             ImmunoPharmaceutical (SMIP) known
                                             as TRU-015, including any
                                             derivatives and improvements
                                             thereof; and, when the context
                                             requires, the term "Product" also
                                             means and refers any and all
                                             tangible forms of the Product which
                                             are manufactured under this
                                             Agreement using the Process,
                                             including without limitation all
                                             in-process intermediates, samples,
                                             derivatives, and improvements
                                             thereof.

     "Quality Agreement"                     means and refers to the quality
                                             agreement between the parties, a
                                             copy of which is attached hereto as
                                             Schedule 4, as amended or varied
                                             from time to time by written
                                             agreement of the parties;

     "Run" or "run"                          means a single fermentation start
                                             of the manufacturing Process at
                                             LB's facility.

     "Services"                              means all or any part of the
                                             services to be performed by LB
                                             under this Agreement (including,
                                             without limitation, cell culture
                                             evaluation, purification
                                             evaluation, master, working and
                                             extended cell bank creation, sample
                                             and bulk production, testing of
                                             finished Product after fill-finish
                                             processing of bulk Product at a
                                             third party facility), as more
                                             particularly set out in Schedule 2.
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        9

<PAGE>

<TABLE>
<S>                                          <C>
     "Specialized Raw Materials"             has the meaning given to it in
                                             Clause 3.10 below.

     "Specifications"                        means the quality, functional and
                                             analytical specifications for
                                             Product, the particulars of which
                                             are set out in Schedule 1.

     "Terms of Payment"                      means the terms of payment
                                             specified in Schedule 3.

     "Testing Laboratories"                  means any third party who has been
                                             instructed by LB and authorized by
                                             Customer to carry out tests on the
                                             Cell Line or the Product.
</TABLE>

References to the singular number include the plural and vice versa, references
to Clauses and Schedules are references to clauses and schedules to this
Agreement.

     2.   CUSTOMER OBLIGATIONS, WARRANTIES AND INDEMNITIES

          2.1 Customer shall pay the Price set out in Schedule 3 for provision
of the Services together with any additional costs and expenses mutually agreed
upon in writing by the parties that fall due under this Agreement in accordance
with the Terms of Payment.

          2.2 As agreed by the parties, the Customer shall supply to LB certain
Customer Know-How, together with full details of any hazards known to Customer
relating to the Cell Line and/or the Customer Materials, and their storage and
use. On review of this Customer Know-How by LB, the Cell Line and/or the
Customer Materials shall be provided to LB at LB's request, all as set forth
with more particularity in and in accordance with Schedule 2 (Services) hereto.
All right, title, and interest in and to the Cell Line, the Customer Materials,
the Customer Know-How and any other Customer Technology supplied to LB in
connection with this Agreement or the August 2003 Services Agreement shall, as
between the parties, remain vested in the Customer. Risk of loss to the Cell
Line, Customer Materials and any tangible Customer Information supplied to LB
under this Agreement shall transfer to LB upon delivery to LB premises.

          2.3 Subject to the terms and conditions of this Agreement, the
Customer hereby grants LB the non-exclusive, non-transferable (other than to
LB's Affiliates), right to use the Cell Line, the Customer Materials, the
Customer Know-How, and the New Customer Intellectual Property during the term of
this Agreement solely for the purpose of providing Services under this
Agreement.

          2.4 The Customer warrants and covenants to LB that:

               2.4.1 Customer has the right to enter into this Agreement;

               2.4.2 ***;

                                                          CONFIDENTIAL TREATMENT

                                       10
<PAGE>

               2.4.3 ***;

               2.4.4 ***;

               2.4.5 Customer will promptly notify LB in writing if it receives
or is notified of a lawsuit that has been filed against Customer which includes
a claim from a third party that the Cell Line, other Customer Materials,
Customer Know-How, Customer Patent Rights, Customer Process, or New Customer
Intellectual Property infringes any intellectual property rights of such third
party or that the use by LB thereof for the provision of the Services infringes
any intellectual property rights of such third party; and

               2.4.6 ***.

          2.5 Subject to Clauses 2.8 and 14 below, and subject to and except to
the extent of any indemnification from LB pursuant to Clause 7 below, the
Customer undertakes to indemnify and to maintain LB promptly indemnified against
all losses, damages, liabilities, settlements, penalties, fines, costs and
expenses of any nature (including court costs and reasonable legal fees on a
full indemnity basis), that LB may incur to the extent such liabilities arise
directly out of or result from any claim, lawsuit or other action by a third
party arising out of or resulting from any breach of any of the warranties given
by the Customer under Clause 2.4 above..

          2.6 Subject to Clauses 2.8 and 14 below, and subject to and except to
the extent of any indemnification from LB pursuant to Clause 7 below, the
Customer shall further indemnify and maintain LB promptly indemnified against
all losses, damages, liabilities, settlements, penalties, fines, costs and
expenses of any nature (including court costs and reasonable legal fees on a
full indemnity basis), that LB may incur arising out of or resulting from:

               2.6.1 any product liability in respect of Product, unless such
liability is caused by the negligent act or omission or willful misconduct of
LB, including without limitation in the production and/or supply of Product; and

               2.6.2 any negligent act or omission or willful misconduct of the
Customer in relation to the use, further processing, storage or sale of the
Product.

          2.7 A party that intends to claim indemnification under this Agreement
(the "Indemnitee") shall promptly notify the indemnifying party (the
"Indemnitor") in writing of any third party claim, suit or proceeding included
within the scope of the indemnification) described in Clauses 2 or 7 hereunder
(each a "Claim") with respect to which the Indemnitee intends to claim such
indemnification, and shall tender the defense of such Claim to the Indemnitor,
and the Indemnitor shall have sole control of the defense and/or settlement of
such Claim. An Indemnitee hereunder shall have the right to retain its own
counsel, subject to the following conditions: (a) the Indemnitee's counsel's
role shall be limited to monitoring the Claim and performing a watching brief of
the Claim and the Indemnitee's counsel shall have no right to actively
participate in the defense and/or settlement of such Claim; and (b) the
Indemnitor shall have the right to veto the Indemnitee's selection of counsel,
acting reasonably and having provided substantive justification

                                                          CONFIDENTIAL TREATMENT

                                       11

<PAGE>

for such veto. So long as the foregoing conditions are met, the Indemnitor shall
bear the reasonable costs and expenses of one attorney acting as the
Indemnitee's counsel in accordance with this Clause 2.7, subject to the
following additional conditions: (x) the attorney's hourly rate must be
reasonable and cannot exceed the prevailing rate, based on the venue of the
claim, suit or proceeding; and (y) the Indemnitor shall have the right to review
and approve the Indemnitee's counsel's invoices. The indemnification obligations
under this Agreement shall not apply to amounts paid in settlement of any Claim
if such settlement is effected without the consent of the Indemnitor, such
consent not to be unreasonably withheld. At the Indemnitor's request and
expense, each Indemnitee shall, and shall cause its employees to, provide full
information and reasonable assistance to Indemnitor and its legal
representatives with respect to the related Claim(s).

          2.8 Notwithstanding anything herein seemingly to the contrary,
Customer shall have no indemnity obligations under this Clause 2 for any losses,
damages, liabilities, settlements, penalties, fines, costs and expenses to the
extent such losses, damages, liabilities, settlements, penalties, fines, costs
and expenses arise out of or result from:

               2.8.1 ***; or

               2.8.2 ***, or

               2.8.3 ***; or

               2.8.4 ***.

          2.9 The provisions of this Clause 2, and the obligations of the
Customer and LB, respectively, under this Clause 2, shall survive the expiration
or termination for whatever reason of the Agreement.

          2.10 CLAUSE 2.4 IS IN LIEU OF ALL OTHER CONDITIONS, WARRANTIES AND
STATEMENTS IN RESPECT OF THE CELL LINE, CUSTOMER MATERIALS, CUSTOMER
INFORMATION, CUSTOMER KNOW-HOW, CUSTOMER PATENT RIGHTS, CUSTOMER PROCESS, NEW
CUSTOMER INTELLECTUAL PROPERTY, AND CUSTOMER TECHNOLOGY, WHETHER EXPRESSED OR
IMPLIED BY STATUTE, CUSTOM OF THE TRADE OR OTHERWISE (INCLUDING WITHOUT
LIMITATION ANY SUCH CONDITION, WARRANTY OR STATEMENT RELATING TO THE DESCRIPTION
OR QUALITY OF THE CELL LINE, CUSTOMER MATERIALS, CUSTOMER INFORMATION, CUSTOMER
KNOW-HOW, CUSTOMER PATENT RIGHTS, CUSTOMER PROCESS, NEW CUSTOMER INTELLECTUAL
PROPERTY, AND CUSTOMER TECHNOLOGY, THEIR FITNESS OR SUITABILITY FOR A PARTICULAR
PURPOSE OR USE UNDER ANY CONDITIONS WHETHER OR NOT KNOWN TO CUSTOMER) AND ANY
SUCH CONDITION, WARRANTY OR STATEMENT IS HEREBY EXCLUDED.

     3. PROVISION OF THE SERVICES

                                                          CONFIDENTIAL TREATMENT

                                       12

<PAGE>

          3.1 LB shall diligently carry out the Services as provided in Schedule
2, and shall use all reasonable efforts consistent with levels of effort that LB
uses with its most important customers, to achieve the objectives and estimated
timescales set out in that Schedule and deliver the Product, samples of the
Product, and other Deliverables to Customer as provided in Schedule 2; provided,
however, that the timescales and Product quantities set forth in Schedule 2 are
estimates only. LB shall communicate with Customer regularly regarding LB's
performance of the Services and shall inform Customer promptly if LB determines
that LB will not or may not be able to meet the objectives or timescales, or
deliver the Product quantities, Product samples, or other Deliverables set forth
in Schedule 2.

          3.2 LB shall perform Runs and manufacture the Product in accordance
with this Agreement, and, except as expressly set forth to the contrary in
Schedule 2 or as otherwise agreed to by the parties from time to time, in
compliance with the Legal Requirements, including without limitation the
requirements of cGMP, LB warrants and covenants that, except as expressly set
forth to the contrary in Schedule 2 and in Clause 3.3 below, the Product
resulting from the Runs shall conform to the Specifications. The Product
resulting from the Runs shall be provided to Customer at no additional cost to
Customer over and above the Price, and Customer may make whatever further use of
such Product as Customer shall determine in its sole discretion, provided,
however, that, in accordance with Schedule 2, the Product manufactured in Stage
5 shall not be used in humans.

          3.3 The parties agree that the *** Batches of Product manufactured
under Stage 8 of Schedule 2 attached hereto shall comply fully with cGMP and
with the parameters and target Specifications agreed to jointly by LB and the
Customer, with an emphasis on the safety of the Product for use in human
clinical testing and with pass/fail testing for analytical methods relating to
safety. In addition, notwithstanding anything in Schedule 3 seemingly to the
contrary, with respect to the Batches of Product manufactured under Stage 8,
Customer shall ***.

               3.3.1 ***

     If a failure to perform the Services or produce the Product for Delivery
arises due to a breach of this Agreement by LB, or LB's negligent act or
omission or willful misconduct, Customer shall be entitled to all of its rights
and remedies.

          3.4 LB shall comply with cGMP and the International Committee for
Harmonisation ("ICH") regulatory requirements, from time to time and to the
extent that the foregoing are applicable to the Services. In the event of a
conflict between the ICH regulatory requirements and the cGMP regulatory
requirements, the cGMP regulatory requirements shall prevail, except as may
otherwise be agreed by the parties in writing.

          3.5 LB hereby undertakes not to use the Cell Line, the Customer
Materials, the Customer Information, the Customer Technology, the Customer
Know-How or the Customer Patent Rights, or any part of any of the foregoing, for
any purpose other than to perform the Services and supply Product under this
Agreement. The obligations of LB under this Clause 3.6 shall survive the
expiration or termination for whatever reason of the Agreement.

                                                          CONFIDENTIAL TREATMENT

                                       13

<PAGE>

          3.6 LB shall:

               3.6.1 at all times use best efforts to keep the Cell Line, the
Customer Materials and the Product secure and safe from loss and damage;

               3.6.2 not part with possession of the Cell Line or the Customer
Materials or the Product, except as permitted under Clause 3.8 below for the
purpose of tests at the Testing Laboratories.

          3.7 LB shall procure that all Testing Laboratories are subject to
obligations of confidence and non-use substantially in the form of and at least
as strict as those obligations of confidence and non-use imposed on LB under
this Agreement. Each Testing Laboratory shall be subject to the prior written
approval of Customer, which approval shall not be unreasonably withheld.
Notwithstanding anything herein seemingly to the contrary, Customer shall have
the right, at Customer's option and with no penalty, to enter into an agreement
directly with one or more of the Testing Laboratories, and transfer the
associated testing services from LB under this Agreement to the Testing
Laboratory. LB shall ensure that Customer has the right to perform, directly or
through Customer's representatives, inspections and audits of all Testing
Laboratories, and Customer may condition Customer's approval of any Testing
Laboratory to Customer's performance of and satisfaction with the results of
such an inspection and audit. Customer shall perform and shall cause its
representatives to perform any such inspections and audits in compliance with
Clause 4 of this Agreement. Notwithstanding Customer's approval of any Testing
Laboratory, LB shall not disclose the contents of this Agreement (including
without limitation the Schedules hereto) or any of Customer's Confidential
Information to such approved Testing Laboratory except to the extent necessary
for such Testing Laboratory to conduct the related tests, and LB shall not
transfer possession of any of the Cell Line, Customer Materials or Product to
such approved Testing Laboratory except to the extent necessary for such Testing
Laboratory to conduct the related tests. Neither LB nor Customer shall be liable
in connection with this Agreement for any of the acts or omissions of the
Testing Laboratories. LB waives, releases and agrees not to assert against
Customer any claims for any losses, damages, liabilities, settlements,
penalties, fines, costs and expenses of any nature that LB may incur which
directly or indirectly arise out of or result from any negligent acts or
omissions or willful misconduct of the Testing Laboratories; ***. LB shall, at
Customer's expense, cooperate fully with Customer in the investigation and
prosecution of any claim, lawsuit or other proceeding by Customer against a
Testing Laboratory in connection with this Agreement for losses, damages,
liabilities, settlements, penalties, fines, costs and expenses of any nature
that Customer may incur which directly or indirectly arise out of or result from
any negligent acts or omissions or willful misconduct of the Testing
Laboratories, Nothing in this Clause shall release or shall be deemed to release
either party from any liability which arise out of or result from that party's
own negligent acts or omissions or willful misconduct. This Clause 3.8 shall
survive the expiration or termination for whatever reason of the Agreement.

          3.8 LB shall procure, maintain and store such amounts of raw materials
and components as required for the Runs, and shall perform testing and
evaluation of such materials and components as set forth in the Quality
Agreement attached hereto as Schedule 4 or agreed upon in

                                                          CONFIDENTIAL TREATMENT

                                       14

<PAGE>

writing by the parties, and the cost and expense for such materials and
components and the testing and evaluation of such materials and components shall
be deemed included in the Prices shown on Schedule 3 hereto. LB shall be
responsible for and Customer may assist with oversight and coordination of the
supply logistics for the raw materials and components required for the Runs. LB
shall not procure Specialized Raw Materials (defined below) until authorized to
do so by Customer.

          3.9 The term "Specialized Raw Materials" as used in this Agreement
means the specialized raw materials and components which are used under this
Agreement to manufacture the Product. The parties shall in good faith agree in
writing which raw materials and components shall be deemed to be "Specialized
Raw Materials" for the purposes of this Clause 3.10. In the event the cost and
expense of any Specialized Raw Materials materially exceed LB's original pricing
assumptions for such Specialized Raw Materials under this Agreement, then
Customer shall pay to LB the difference between the assumed cost and expense for
such Specialized Raw Materials and the actual cost and expense (not including
any LB mark-up or administrative fees) for such Specialized Raw Materials.

     4. QUALITY; PROJECT MANAGEMENT

          4.1 Responsibility for quality assurance and quality control shall be
allocated between the parties in accordance with the Quality Agreement, a copy
of which is attached hereto as Schedule 4, and standard operating procedures as
may be agreed upon in writing by the parties from time to time.

          4.2 Customer and its designated representatives shall have the right
to witness, inspect and audit the performance of LB's obligations, at the times
and for durations set forth in the Quality Agreement and as otherwise agreed by
the parties. Customer shall have access to the facilities, data and records of
LB which are related to this Agreement for the purpose of conducting such
inspections and audits, and LB shall use reasonable endeavours to ensure that
all Testing Laboratories provide similar access to the Testing Laboratories'
facilities, data and records which are related to this Agreement for such
purposes. In accordance with the Quality Agreement, Customer shall have the
right to review LB's non-proprietary standard operating procedures relating to
the services of LB under the Quality Agreement or this Agreement.

          4.3 In accordance with the Quality Agreement, Customer will have the
sole right to correspond with and submit regulatory applications and other
filings to the FDA, EMEA and other regulatory authorities to obtain approvals to
import, export, conduct clinical trials with, or take any other action with
respect to the Product, alone or with other products (collectively,
"Approvals"), when and as Customer may deem useful or necessary. Accordingly,
except as otherwise required by Legal Requirements, LB will not correspond
directly with the FDA, EMEA or any other regulatory agency with respect to the
Product without, in each instance, first obtaining Customer's prior written
consent. Notwithstanding the foregoing, LB will assist Customer, as requested by
Customer and at Customer's expense, in preparing, submitting, and maintaining
applications for such Approvals.

          4.4 As set forth with particularity in the Quality Agreement, LB will
permit the FDA, EMEA and other regulatory authorities to conduct inspections of
LB's facilities as the FDA,

                                                          CONFIDENTIAL TREATMENT

                                       15

<PAGE>

EMEA or other regulatory authorities may request, and will cooperate with the
FDA, EMEA or other regulatory authorities with respect to the inspections and
any related matters, in each case related to the Product.

          4.5 Notwithstanding anything in this Agreement seemingly to the
contrary, LB shall not undertake any modifications to the Process or testing
processes that could delay or otherwise impact the Approvals or other regulatory
submissions, including without limitation, regulatory product reviews,
Investigational New Drug applications (INDs), or any other compliance status
without in each case the prior written agreement of Customer.

          4.6 In accordance with the Quality Agreement, Customer shall have the
right (a) to review the specifications, grades and vendors of all raw materials
and components used under this Agreement to manufacture the Product, and (b) to
approve the specifications, grades and vendors of all Critical Raw Materials
(defined below), including excipients, and of all raw materials and components
of animal or human origin, all to the extent used under this Agreement to
manufacture the Product. Customer shall provide a written list to LB of those
certain raw materials and components which shall constitute and be deemed to be
"Critical Raw Materials" for purposes of this Agreement, and shall update the
list from time to time as appropriate. Each version of the written list of the
Critical Raw Materials shall be jointly agreed to by Customer and LB. Raw
materials of and components of animal or human origin shall be avoided when
possible.

          4.7 By not later than March 31, 2004, the Parties will establish a
Joint Project Team (the "JPT"). The JPT shall be composed of representatives
appointed by each of LB and the Customer. Such representatives may include, but
not be limited to, the Project Manager, Technical Lead, Manufacturing Lead,
Quality Control Lead, Quality Assurance/Regulatory Lead, Raw Materials Lead,
Supply Chain Lead and Engineering Lead, or other individuals with expertise and
responsibilities in the same areas of manufacturing, process sciences, quality
control or regulatory affairs. The JPT will meet by teleconference at least once
each week, or more frequently, as agreed by the JPT. The JPT will operate by
unanimous decision, except as expressly set forth herein. If the JPT is unable
to resolve a dispute regarding any issue presented to it, such dispute shall be
resolved in accordance with Clause 11.4. The JPT is responsible for the daily
monitoring and guidance of the Services to successfully achieve the deliverables
of the project as outlined herein.

          4.8 By not later than March 31, 2004, each Party shall appoint a
Project Manager to act as the primary contact for such Party in connection with
matters related to the performance of the Services. Each such Project Manager,
unless otherwise mutually agreed, shall serve as a member of the JPT.

          4.9 As set forth in the Quality Agreement, Customer shall have the
right to designate one of its employees or consultants as Customer's person on
plant, to be present in LB's facility during normal business hours during the
term of this Agreement to observe the Runs and observe LB's performance of its
obligations under this Agreement at times and for durations to be agreed. While
at LB's facility, Customer's representative shall comply with all of LB's
applicable policies and procedures, and, at LB's option, shall be escorted by LB
personnel.

                                                          CONFIDENTIAL TREATMENT

                                       16

<PAGE>

     5. DELIVERY, TRANSPORTATION OF PRODUCT AND CUSTOMER TESTS

          5.1 *** Unless otherwise agreed, LB shall package and label
Manufactured Product for Delivery in accordance with the Specifications and its
standard operating procedures and all applicable Legal Requirements. It shall be
the responsibility of the Customer to inform LB in writing in advance of any
special packaging and labeling requirements for Manufactured Product. All
additional costs and expenses of whatever nature incurred by LB in complying
with such special requirements shall be charged to the Customer in addition to
the Price, Transportation of Manufactured Product, whether or not under any
arrangements made by LB on behalf of Customer, shall be made at the sole risk
and expense of the Customer, provided that LB has complied with any instructions
provided by Customer with respect to transportation and insurance as set forth
in Clauses 5.2 and 5.3 below.

          5.2 If requested in writing by the Customer, LB will (acting as agent
of the Customer for such purpose) arrange the transportation of Manufactured
Product from LB's premises to the third-party fill-finish contractor or other
destination indicated by the Customer, together with insurance coverage for
Manufactured Product in transit at its invoiced value. All additional reasonable
costs and expenses of whatever nature incurred by LB in arranging such
transportation and insurance shall be charged to the Customer in addition to the
Price provided that LB has obtained Customer's prior written consent to
incurring such additional costs and expenses.

          5.3 If requested in writing by the Customer, LB will (acting as agent
for Customer) arrange for insurance of Product whilst held by LB after Delivery
(awaiting transportation). The costs and expenses of such insurance shall be at
Customer's expense and on reasonable terms equivalent to those under which LB
insures other comparable products prior to Delivery. All such additional
reasonable costs and expenses of whatever nature incurred by LB in arranging
such insurance shall be charged to the Customer in addition to the Price,
provided that LB has obtained Customer's prior written consent to incurring such
additional costs and expenses. Notwithstanding the foregoing, in the event LB
has been requested to arrange the transportation of Manufactured Product in
accordance with Clause 5.2 above, the costs and expenses of such insurance of
Manufactured Product whilst held by LB after Delivery (awaiting transportation)
shall be at LB's expense for up to fourteen (14) days and thereafter shall be at
Customer's expense, provided, however, that in the event the delay in
transportation is caused by LB, then the costs and expenses of such insurance
shall be at LB's expense until the Manufactured Product has been loaded onto the
appropriate collecting vehicle, except as may be otherwise agreed by the parties
in writing.

          5.4 LB shall deliver to Customer the Certificate of Analysis not later
than the date of Delivery. Notwithstanding the foregoing, at Customer's request,
LB will Deliver Manufactured Product in quarantine prior to delivery of the
Certificate of Analysis. Such request shall be accompanied by Customer's written
acknowledgement that the Manufactured Product has been Delivered without the
transmittal to Customer of a Certificate of Analysis, that accordingly the
Manufactured Product cannot be administered to humans until transmittal of the
Certificate of Analysis, and that Customer nevertheless accepts full risk of
loss to and title and ownership of the Manufactured Product. The Delivery of
Product in quarantine shall be subject to such testing

                                                          CONFIDENTIAL TREATMENT

                                       17

<PAGE>

requirements as LB may reasonably require, and the *** period referred to in
Clause 5.7 shall run from Customer's receipt of samples of such Manufactured
Product together with the related consolidated Batch record.

          5.5 Where LB has made arrangements for the transportation of
Manufactured Product, the Customer shall diligently examine the Manufactured
Product as soon as practicable after receipt. Notice of all claims (time being
of the essence) arising out of:

               5.5.1 visible damage to or total or partial loss of Manufactured
Product in transit shall be given in writing to LB within *** of receipt by
Customer at Customer's facility or of receipt by Customer's third party supplier
at such third party's facility; or

               5.5.2 non-Delivery shall be given in writing to LB within ***
after the later of (a) the date of LB's despatch notice, and (b) Customer's
actual knowledge of non-Delivery.

          5.6 The Customer shall make damaged Manufactured Product and
associated packaging materials available for inspection and shall comply with
the requirements of any insurance policy covering the Manufactured Product of
which LB has given Customer notice. LB shall offer the Customer all reasonable
assistance (at the cost and expense of the Customer) in pursuing any claims
arising out of the transportation of Manufactured Product.

          5.7 LB shall deliver to Customer samples of all Batches manufactured
under this Agreement, as and when Batches are manufactured, together with the
related consolidated Batch record requested by Customer to enable Customer to
inspect and perform testing on such samples. Promptly following receipt of
Manufactured Product or any sample thereof, the Customer may inspect the
Manufactured Product or sample and carry out any of the tests outlined or
referred to in the Specifications set out in Schedule 1 and such additional
tests as may be prudent in Customer's reasonable discretion. Subject to Clause
3.2, if such tests show that the Manufactured Product fails to meet the
Specifications, the Customer shall give LB written notice thereof within ***
after Customer's receipt at Customer's facility of samples of such Batch
together with the related consolidated Batch record and shall return such
Manufactured Product (except for reference samples retained by Customer) at LB's
expense to LB's premises for further testing. In the absence of such written
notice, Manufactured Product shall be deemed to have been accepted by the
Customer as meeting the Specifications. Subject to Clause 3.2, if Customer has
reasonably demonstrated to LB that Manufactured Product returned to LB fails to
meet the Specifications, and LB has failed to prove that such failure is due (in
whole or in part) to acts or omissions of the Customer or any third party after
Delivery, LB shall at Customer's discretion refund that part of the Price that
relates to the production of such Manufactured Product or replace such
Manufactured Product at LB's own cost and expense. In the event Customer
requires LB to replace such Manufactured Product, LB shall use all reasonable
endeavours to do so as soon as possible with the minimum delay.

          5.8 Subject to Clause 3.2, if there is any dispute concerning whether
Manufactured Product returned to LB fails to meet the Specifications or whether
such failure is due (in whole or in part) to acts or omissions of the Customer
or any third party after Delivery, such

                                                          CONFIDENTIAL TREATMENT

                                       18

<PAGE>

dispute shall be resolved in accordance with the dispute resolution procedures
described in Clause 11.4 below.

          5.9 Subject to Clause 7, LB's liability hereunder in respect of
Manufactured Product that fails to meet the Specifications shall be limited to
refund or replacement, in accordance with and as set forth with more
particularity in Clause 5,7 above; provided, however, that the foregoing
limitation of liability shall not apply in the event such failure is caused by
the negligent act or omission or willful misconduct of LB.

     6. PRICE AND TERMS OF PAYMENT

          6.1 Unless otherwise indicated in writing by LB, all prices and
charges payable to Lonza are exclusive of Value Added Tax or of any other
applicable taxes, levies, imposts, duties and fees of whatever nature imposed by
or under the authority of any government or public authority, which shall be
paid by the Customer (other than taxes on LB's income). LB shall add all such
taxes as separate line items on invoices. All invoices are strictly net and
payment must be made within thirty (30) days of Customer's receipt of invoice.
Notwithstanding the foregoing, no amounts shall be invoiced until such amounts
are then due and payable in accordance with the Schedules to this Agreement,
including without limitation and as appropriate the completion of the related
Services and Customer's receipt and acceptance of the related Deliverables. The
invoices shall be in ***, and all payments made by Customer shall be made in
***.

          6.2 In default of payment on due date:

               6.2.1 interest shall accrue on any amount overdue at the per
annum interest rate *** above *** from time to time as published in the "Money
Rates" section of The Wall Street Journal, on the 1st business day of each
month, beginning with the month in which the payment became delinquent, with
interest to accrue on a day to day basis both before and after judgement, adjust
monthly on the 1st day of each month, beginning with the second month of
delinquency, and be calculated on the number of days such payment is delinquent;
and

               6.2.2 For so long as such payment delinquency remains uncured, LB
shall, at its sole discretion, and without prejudice to any other of its accrued
rights, be entitled to suspend the provision of the Services or, if Customer has
not remedied such payment delinquency within *** of the receipt by Customer of
notice of nonpayment and demand for remedy, to treat the Agreement as
repudiated.

     7. LB WARRANTIES AND COVENANTS AND INDEMNITY

          7.1 LB warrants and covenants that:

               7.1.1 the Services shall be performed in accordance with this
Agreement, including without limitation Clauses 3.1 and 3.2 above;

                                                          CONFIDENTIAL TREATMENT

                                       19
<PAGE>

               7.1.2 LB has the right and necessary corporate authorisations to
enter into this Agreement;

               7.1.3 LB has the necessary rights to licence or permit Customer
to use the LB Process, LB Know-How, LB Patent Rights, and New General
Application Intellectual Property in accordance with the terms of this
Agreement, including without limitation in accordance with and pursuant to
Clause 9 below;

               7.1.4 any of the LB Process, LB Know-How, LB Patent Rights, and
New General Application Intellectual Property referred to in Clause 7.1.3 above
that are not owned by LB are licensed to LB under a licence which grants LB the
necessary rights to licence or permit Customer to use the LB Process, LB
Know-How, LB Patent Rights, and New General Application Intellectual Property in
accordance with the terms of this Agreement, including without limitation in
accordance with and pursuant to Clause 9 below;

               7.1.5 LB will not cause or permit any liens or encumbrances of
any kind arising through LB to attach to Product, and unencumbered title to
Manufactured Product will be conveyed to Customer upon Delivery;

               7.1.6 the LB Know How, LB Patent Rights, LB Process and the New
General Application Intellectual Property are owned by LB or LB is otherwise
entitled to use them for the purposes of providing Services under this Agreement
and LB shall not do or cause anything to be done which would adversely affect
their ownership or entitlement to use the same for those purposes;

               7.1.7 to the best of LB's knowledge and belief, the use of the LB
Process, LB Know-How, LB Patent Rights, and New General Application Intellectual
Property in accordance with the terms of this Agreement (including without
limitation the use by Customer in accordance with and pursuant to the provisions
of Clause 9 below) do not and will not infringe any intellectual property rights
or industrial property rights of any third party (including without limitation
any LB Affiliate) and do not involve the wrongful use of any trade secret or
confidential information, nor is there any claim to the contrary outstanding;

               7.1.8 LB will notify Customer in writing immediately if it
receives or is notified of a claim that the use by LB of the LB Process, LB
Know-How, LB Patent Rights and/or New General Application Intellectual Property
for Services or the use by Customer in accordance with the terms of this
Agreement infringes any third party's intellectual property rights or industrial
property rights or involves the wrongful use of any trade secret or confidential
information; and

               7.1.9 at the date of this Agreement LB is not a party to any
agreement that prohibits or prevents it from performing the Services or
otherwise fulfilling its obligations under this Agreement and covenants that it
will not enter into any such agreement.

          7.2 CLAUSES 3, 4 AND 7.1 ARE IN LIEU OF ALL CONDITIONS, WARRANTIES AND
STATEMENTS IN RESPECT OF THE SERVICES AND/OR THE

                                                          CONFIDENTIAL TREATMENT

                                       20

<PAGE>

PRODUCT WHETHER EXPRESSED OR IMPLIED BY STATUTE, CUSTOM OF THE TRADE OR
OTHERWISE (INCLUDING BUT WITHOUT LIMITATION ANY SUCH CONDITION, WARRANTY OR
STATEMENT RELATING TO THE DESCRIPTION OR QUALITY OF THE PRODUCT, ITS FITNESS OR
SUITABILITY FOR A PARTICULAR PURPOSE OR USE UNDER ANY CONDITIONS WHETHER OR NOT
KNOWN TO LB) AND ANY SUCH CONDITION, WARRANTY OR STATEMENT IS HEREBY EXCLUDED.

          7.3 Subject to and except to the extent of any indemnification from
Customer pursuant to Clauses 2.5 and 2.6 above, LB undertakes to indemnify and
to maintain Customer promptly indemnified against all losses, damages,
liabilities, settlements, penalties, fines, costs and expenses of any nature
(including court costs and reasonable legal fees on a full indemnity basis),
that Customer may incur to the extent such liabilities arise directly out of or
result from any claim, lawsuit or other action by a third party arising out of
or resulting from (a) any breach of any of the warranties given by LB in Clause
7.1 above; or (b) any negligent act or omission or willful misconduct of LB.

          7.4 Notwithstanding anything herein seemingly to the contrary, LB
shall have no indemnity obligations under this Clause 7 for any losses, damages,
liabilities, settlements, penalties, fines, costs or expenses to the extent such
losses, damages, liabilities, settlements, penalties, fines, costs and expenses
arise out of or result from: ***

          7.5 Nothing contained in this Agreement shall purport to exclude or
restrict any liability for death or personal injury resulting directly from
negligence by LB in carrying out the Services or any liability for breach of the
implied undertakings of LB as to title.

          7.6 This Clause 7 and the obligations of LB under this Clause 7 shall
survive the expiration or termination for whatever reason of the Agreement.

     8. CONFIDENTIALITY AND NON-USE

          8.1 The Customer acknowledges that LB Know-How, LB Process, LB Patent
Rights and General Application Intellectual Property and any of LB's other
Intellectual Properly disclosed to, supplied to or held by Customer pursuant to
this Agreement, and LB acknowledges that Customer Know-How, Customer Patent
Rights, Customer Technology, Customer Information, Customer Process, New
Customer Intellectual Property, Customer Materials and the Cell Line and any of
Customer's other Intellectual Property disclosed to, supplied to or held by LB
pursuant to this Agreement (all of the foregoing collectively referred to as
"Confidential Information") is, subject to Clause 8.5, supplied and shall be
held in circumstances imparting an obligation of confidence and each agrees to
keep the other party's Confidential Information secret and confidential and to
respect the other's proprietary rights therein and not at any time for any
reason whatsoever to disclose or permit such Confidential Information to be
disclosed to any third party save as expressly provided herein or to be used for
any purpose not expressly authorized under this Agreement For the avoidance of
doubt, the parties agree that all portions of documents and records describing
and to the extent relating to the Product and the Customer Process shall be kept
confidential by Lonza in accordance with the terms of this Clause 8.

                                                          CONFIDENTIAL TREATMENT

                                       21

<PAGE>

          8.2 The Customer and LB shall each procure that all their respective
employees, consultants, contractors and persons for whom it is responsible
having access to the other party's Confidential Information shall be subject to
the same obligations of confidence as the principals pursuant to Clauses 8.1 and
8.3 and, in addition, with respect to LB, to the same obligations of non-use
pursuant to Clauses 2.3, 3.6 and 8.1, and shall be bound, by written
confidentiality agreements in support of all such obligations.

          8.3 LB and the Customer each undertake, except as set forth herein,
not to disclose or permit to be disclosed to any third party, or otherwise make
use of or permit to be made use of (a) any Confidential Information of the
other, or of any Affiliate of the other, or of any suppliers, agents,
distributors, licensees or other customers of the other which comes into the
receiving party's possession under this Agreement or (b) the commercial terms of
this Agreement, except to the extent that any of the foregoing is required to be
disclosed pursuant to subpoena, court order, judicial process or otherwise by
law, provided the receiving party provides prompt notice to the disclosing party
of such requirement in order to give the disclosing party an opportunity to
timely seek a protective order or other appropriate judicial relief. In the
event the disclosing party is unable to obtain a protective order or other
appropriate judicial relief, the receiving party shall disclose only that
portion of the disclosing party's Confidential Information which is legally
required to be disclosed, and ensure that all such Confidential Information of
the disclosing party shall be redacted to the fullest extent permitted by law
prior to such disclosure and that the disclosing party shall be given an
opportunity to review the Confidential Information prior to its disclosure.
Notwithstanding the foregoing, (i) LB may disclose Customer's Confidential
Information to LB's Affiliate, Lonza Biologics, Inc., for purposes consistent
with this Agreement; provided, however, that LB shall ensure that its Affiliate
is subject to obligations of confidentiality and non-use with respect to the
Confidential Information at least as strict as those set forth herein, and
provided further that LB shall remain liable for the acts or omissions of its
Affiliate with respect to such Confidential Information, and (ii) either party
may disclose the other party's Confidential Information to any contractors or
consultants approved in writing by the other party, such approval not to be
unreasonably withheld or delayed, for purposes consistent with this Agreement;
provided, however, that in each case the party disclosing the other party's
Confidential Information shall ensure that the third party receiving the
information is subject to contractual obligations of confidentiality and non-use
with respect to the Confidential Information at least as strict as those set
forth herein; and provided further that the party disclosing the other party's
Confidential Information shall remain liable for the acts or omissions of such
third party with respect to such Confidential Information.

          8.4 The obligations of confidence referred to in this Clause 8 shall
not extend to any information which:

               8.4.1 is or becomes generally available to the public otherwise
than by reason of a breach by the recipient party of the provisions of this
Clause 8;

               8.4.2 is known to the recipient party and is at its free
disposal, without an obligation of confidence, prior to its receipt from the
disclosing party;

                                                          CONFIDENTIAL TREATMENT

                                       22

<PAGE>

               8.4.3 is subsequently disclosed to the recipient party without
being made subject to an obligation of confidence; or

               8.4.4 is developed by any servant or agent of the recipient party
without access to or use or knowledge of the Confidential Information of the
disclosing party.

          8.5 The parties acknowledge that:

               8.5.1 without prejudice to any other rights and remedies that the
parties may have, the parties agree that the Confidential Information is
valuable and that damages may not be an adequate remedy for any breach of the
provisions of Clauses 2.3, 3.6, 8.1, 8.2, 8.3 and 8.4. The parties agree that
the relevant party will be entitled without proof of special damage to the
remedies of an injunction and other equitable relief for any actual or
threatened breach by the other party;

               8.5.2 Customer acknowledges that, save as expressly provided in
this Agreement (including without limitation Clauses 9.8.4 and 9.8.7 below), the
Customer shall not at any time have any right, title, license or interest in or
to LB Know-How, the LB Patent Rights, the LB Process, the New General
Application Intellectual Property or any of LB's other Intellectual Property,
and

               8.5.3 LB acknowledges that, save as expressly provided in this
Agreement, LB shall not at any time have any right, title, license or interest
in or to the Customer Information, the Customer Materials, the Cell Line,
Customer Know-How, Customer Patent Rights, the Customer Technology, the New
Customer Intellectual Property, the Customer Process or any of Customer's other
Intellectual Property.

          8.6 This Clause 8 and the obligations of LB and the Customer under
this Clause 8 shall survive the expiration or termination for whatever reason of
the Agreement.

     9. TERMINATION; OWNERSHIP; LICENSE RIGHTS

          9.1 This Agreement shall begin on the Effective Date and, unless
earlier terminated as set forth in this Clause 9, shall terminate and expire
when the last obligation to be performed under this Agreement has been
performed. If it becomes apparent to either LB or the Customer at any stage in
the provision of the Services that it will not be possible to complete the
Services for scientific or technical reasons, and such party gives written
notice thereof to the other party, *** period shall be allowed for good faith
discussion and attempts to resolve such problems. If such problems are not
resolved within such period, LB and the Customer shall each have the right to
terminate the Agreement forthwith by notice in writing. In the event of such
termination, the Customer shall pay to LB a termination sum calculated by
reference ***.

          9.2 Customer may in its sole discretion terminate the Services at any
time for any reason or for no reason whatsoever by giving not less than ***
notice in writing to LB. In the event of termination pursuant to this Clause 9.2
and subject to Clauses 9.4 and 9.5, the Customer shall pay LB a termination sum
calculated in accordance with the principles of Clause 9.1 above plus;

                                                          CONFIDENTIAL TREATMENT

                                       23

<PAGE>

               9.2.1 in the event notice to terminate Services pursuant to this
Clause 9.2 is issued to LB ***or less before LB's then estimated start date for
any stage of those Services which include cGMP fermentation activities, Customer
shall pay LB a sum ***, which payment shall fall due to LB on or before the date
of termination of such Services; or

               9.2.2 in the event notice to terminate Services pursuant to this
Clause 9.2 is issued to LB more than *** but not more than *** before LB's then
estimated start date for any stage of those Services which include cGMP
fermentation activities, Customer shall pay LB a sum equal to ***, which payment
shall fall due to LB on or before the date of termination of such Services; or

               9.2.3 in the event notice to terminate Services pursuant to this
Clause 9.2 is issued to LB more than *** before LB's then estimated start date
for any stage of Services which include cGMP fermentation activities, no payment
shall be due for the stage or stages in question.

          9.3 The obligation to make payment under Clause 9.2 shall be reduced
(retrospectively, and hence LB shall make an appropriate refund to Customer) to
the extent that LB mitigates its loss in this regard (and LB shall promptly
notify the Customer of any such mitigation). LB shall make all reasonable
efforts so to mitigate such losses. This provision shall not entitle the
Customer to be refunded an amount greater than that paid by Customer to LB
pursuant to this Clause 9 ***.

          9.4 For the avoidance of doubt, activities relating to cGMP
fermentation shall be deemed to commence with the date of removal of the vial of
cells for the performance of the fermentation from frozen storage.

          9.5 In addition to the termination rights set forth above, the parties
may each terminate the Agreement forthwith by notice in writing to the other
party upon the occurrence of any of the following events:

               9.5.1 if one party commits a material breach of the Agreement
(which shall include without limitation a breach of the warranties set out in
Clauses 2 and 7 respectively), and such breach is not capable of remedy, then
the non-breaching party may terminate the Agreement forthwith by notice in
writing to the breaching party, and, if such breach is capable of remedy but is
not remedied within *** of the receipt by the breaching party of notice
identifying the breach and requiring its remedy, then the non-breaching party
may terminate the Agreement forthwith by notice in writing to the breaching
party; or

               9.5.2 if one party ceases for any reason to carry on business or
compounds with or convenes a meeting of its creditors or has a receiver or
manager appointed in respect of all or any part of its assets or is the subject
of an application for an administration order or of any proposal for a voluntary
arrangement or enters into liquidation (whether compulsorily or voluntarily) or
undergoes any analogous act or proceedings under foreign law, then the other
party may terminate the Agreement forthwith by notice in writing to the
breaching party.

                                                          CONFIDENTIAL TREATMENT

                                       24

<PAGE>

          9.6 Upon the termination or expiration of the Agreement for whatever
reason:

               9.6.1 LB shall cease all use of and shall promptly return to the
Customer all Customer Information and shall, as directed by Customer, dispose of
or return to the Customer the Customer Materials, the Cell Line, the Product,
the Deliverables, the Documentation, any in-process Product or materials, and
any materials deriving from any of the foregoing. Notwithstanding the foregoing,
the parties agree that, in the event LB has terminated the Agreement pursuant to
Clause 9.5.1 above because of a material payment default by Trubion, men LB
shall have no obligation to deliver Manufactured Product (or Product to the
extent the term "Product" refers to the tangible forms of the Product
manufactured under this Agreement using the Process) to Trubion as required
under this Clause 9.6.1 unless and until the payment default has been cured;

               9.6.2 LB shall not thereafter use or exploit the Customer
Know-How, Customer Patent Rights, the Customer Technology, the New Customer
Intellectual Property (including without limitation the Customer Process), the
Customer Information, the Cell Line, the Product, or the Customer Materials, or
any of Customer's other Intellectual Property;

               9.6.3 the Customer shall promptly return to LB all LB Know-How it
has received from LB;

               9.6.4 the Customer shall not thereafter use or exploit the LB
Patent Rights the LB Process or the LB Know-How or any of LB's other
Intellectual Property in any way whatsoever, except as permitted under and in
accordance with Clauses 9.8.4, 9.8.7, and 9.9 below and subject to the
provisions set forth in Clause 9.10 below;

               9.6.5 LB shall refund within thirty (30) days of the effective
date of such termination all amounts paid to LB in excess of the amounts owed to
LB under this Agreement, including without limitation the amounts owed to LB if
any, pursuant to this Clause 9; and

               9.6.6 LB and the Customer shall do all such acts and things and
shall sign and execute all such deeds and documents as the other may reasonably
require to evidence compliance with this Clause 9.6.

          9.7 Expiration or termination of the Agreement for whatever reason
shall not affect the accrued rights of either LB or the Customer arising under
or out of this Agreement and all provisions which are expressed to survive the
Agreement shall remain in full force and effect. For the avoidance of doubt, the
provisions of Clauses 2, 3, 7, 8, 9, 11 and 14 will survive the expiration or
termination of this Agreement for any reason, and, except as otherwise expressly
provided in this Clause 9.7, all other rights and obligations of the parties
under this Agreement will terminate upon termination or expiration of this
Agreement.

          9.8 Ownership; License Rights.

               9.8.1 Except as expressly provided in Clause 2.3 above and Clause
9.8.7 below, neither party will, as a result of this Agreement, acquire any
right, title, or interest in any

                                       25

<PAGE>

Intellectual Property that the other party owned or controlled as of the
Effective Date of this Agreement, or that the other party obtains ownership or
control of separate and apart from the performance of this Agreement.

               9.8.2 Except as expressly provided in Clause 9.8.4 below, LB
shall own all right, title and interest in "New General Application Intellectual
Property." which as used in this Agreement means Intellectual Property that LB
and/or its Affiliates, contractors or agents develops, conceives, invents,
reduces to practice or makes in the course of performance of this Agreement and
that meets each of the following three criteria: ***.

               9.8.3 Except for and not including the New General Application
Intellectual Property, Customer shall own all right, title, and interest in any
and all Intellectual Property that LB and/or its Affiliates, the Testing
Laboratories or other contractors or agents of LB conceives, invents, reduces to
practice, develops or makes, solely or jointly with Customer or others, in the
course of performance of this Agreement or as a result of receipt of Customer
Technology (collectively, the "New Customer Intellectual Property"), including
without limitation the Customer Process and all improvements to the Customer
Technology. For the avoidance of doubt, the parties confirm that LB shall have
no obligation to cause any of the Testing Laboratories or other contractors or
agents of LB to assign their respective rights, titles and interests in any New
Customer Intellectual Property to Trubion, other than the obligations set forth
in Clause 9.8.5 below. LB hereby assigns to Customer and shall continue to
assign to Customer all of its right, title and interest in any New Customer
Intellectual Property. LB shall promptly disclose to Customer in writing all New
Customer Intellectual Property. LB shall execute, and shall require LB's
personnel involved in the performance of the Services to execute, any documents
required to confirm Customer's ownership of the New Customer Intellectual
Property, and any documents required to apply for, maintain and enforce any
patents or other rights in the New Customer Intellectual Property. Upon
Customer's request and at Customer's reasonable expense, and at no cost to LB,
LB shall assist Customer as may he necessary to apply for, maintain and enforce
any patents or other rights in the New Customer Intellectual Property. For the
avoidance of doubt, the parties agree that the term "New Customer Intellectual
Property" shall not under any circumstances be interpreted or defined to include
any "New General Application Intellectual Property."

               9.8.4 Subject to Clause 9.10 below, LB hereby grants Customer a
non-exclusive, worldwide, fully paid-up, irrevocable and transferable license,
with the right to grant and authorize sublicenses, under and to all New General
Application Intellectual Property, to the extent such New General Application
Intellectual Property is useful or beneficial to develop, conduct clinical
trials for, formulate, manufacture, test, seek regulatory approval for, market,
commercialize, make, have made, use, sell, import, and distribute Product.

               9.8.5 LB shall use its reasonable efforts to procure that all
Testing Laboratories and other contractors arid agents of LB involved in the
performance of the Services, and their respective personnel, shall be subject to
the same agreements and obligations as LB pursuant to Clauses 9.8.3 and 9.8.4,
and shall be bound by written agreements in support of all such agreements and
obligations, including without limitation an assignment to Customer all of the

                                                          CONFIDENTIAL TREATMENT

                                       26

<PAGE>

Testing Laboratories, contractors and agents' right, title and interest in any
New Customer Intellectual Property.

               9.8.6 Upon the earlier of the completion of the Services or the
termination or expiration of this Agreement, LB shall deliver to Customer all
materials related to the New Customer Intellectual Property, regardless of the
method of storage or retrieval, in such form as such materials are then
currently in the possession of LB. Alternatively, at Customer's written request,
LB shall dispose of such related materials or retain them for a period of time
agreed upon by the parties; provided, however, that Customer shall pay the
reasonable costs associated with LB disposing of or retaining such materials.

               9.8.7 Subject to Clause 9.10 below, LB hereby grants Customer a
non-exclusive, worldwide, fully paid-up, irrevocable and transferable license,
with the right to grant and authorize sublicenses, under and to the LB Patent
Rights and LB Know-How to use the LB Patent Rights, the LB Know-How and the LB
Process, alone or in combination with the Customer Process or such other
technology or Intellectual Property that Customer chooses, in its sole
discretion, to develop, conduct clinical trials for, formulate, manufacture,
test, seek regulatory approval for, market, commercialize, make, have made, use,
sell, import, and distribute Product. For the avoidance of doubt, no licence is
granted to Customer under this Clause 9.8.7 or otherwise under this Agreement in
respect of LB's glutamine synthetase (GS) gene expression system, which shall be
the subject of a separate licence agreement between the parties.

          9.9 The parties intend that the Process shall be fully portable by
Trubion. The parties intend that the Process shall be fully portable by Trubion.
At the request of Customer at any time and from time to time during the term of
this Agreement and within *** following the expiration or termination of this
Agreement, LB shall transfer to Customer (or its designee) the Process for the
Product and all manufacturing technology and know-how related thereto (the
"Technology Transfer"). ***.

          9.10 Notwithstanding anything in Clause 9.8.4 or 9.8.7 seemingly to
the contrary, the parties agree as follows:

               9.10.1 Upon the expiration or termination of this Agreement,
Customer shall have no right to exercise the license rights granted by LB to
Customer under Clauses 9.8.4 and 9.8.7 unless and until the Technology Transfer
fee has been paid in accordance with Clause 9.9 above.

               9.10.2 During the term of this Agreement, Customer shall have no
right to exercise the license rights granted by LB to Customer under Clauses
9.8.4 and 9.8.7 to manufacture the Product at a Trubion facility or at a
third-party facility that is not owned or operated by Lonza or its Affiliates,
unless and until the Technology Transfer fee described in Clause 9.9 above has
been paid.

Furthermore, for the avoidance of doubt, the parties agree that the Technology
Transfer shall be performed in accordance with and subject to the provisions of
Clause 9.9, and the parties

                                                          CONFIDENTIAL TREATMENT

                                       27

<PAGE>

acknowledge that Clause 9.9, and the obligations of the parties thereunder,
shall survive the expiration or termination of this Agreement.

          9.11 The terms of this Clause 9 shall survive the expiration or
termination for whatever reason of this Agreement.

     10. FORCE MAJEURE

          10.1 If either party is prevented or delayed in the performance of any
of its obligations under the Agreement by Force Majeure and shall give written
notice thereof to the other party specifying the matters constituting Force
Majeure together with such evidence as the party giving notice reasonably can
give and specifying the period for which it is estimated that such prevention or
delay will continue, the party giving notice shall be excused from the
performance or the punctual performance of such obligations as the case may be
from the date of such notice for so long as such cause of prevention or delay
shall continue. Notwithstanding the foregoing, in the event that LB is prevented
from performance by Force Majeure by longer than ***, Customer shall be entitled
to terminate this Agreement upon written notice, but such termination shall not
be considered as termination under Clause 9.5.1 hereof.

          10.2 The expression "Force Majeure" shall be deemed to include any
cause affecting the performance by a party of the Agreement to the extent that
it arises from or attributable to acts, events, acts of God, omissions or
accidents beyond the reasonable control of the party giving notice of the Force
Majeure event.

     11. GOVERNING LAW, JURISDICTION AND ENFORCEABILITY; DISPUTE RESOLUTION

          11.1 The construction, validity and performance of the Agreement shall
be governed by the laws of ***. This Agreement shall not be governed by the
United Nations Convention on Contracts for the International Sale of Goods, the
application of which is disclaimed.

          11.2 No failure or delay on the part of either LB or the Customer to
exercise or enforce any rights conferred on it by the Agreement shall be
construed or operate as a waiver thereof nor shall any single or partial
exercise of any right, power or privilege or further exercise thereof operate so
as to bar the exercise or enforcement thereof at any time or times thereafter.

          11.3 The illegality or invalidity of any provision (or any part
thereof) of this Agreement shall not affect the legality, validity or
enforceability of the remainder of its provisions or the other parts of such
provision as the ease may be.

          11.4 If any dispute arises relating to the performance of either party
under this Agreement that the parties are unable to resolve in the ordinary
course of business (a "Dispute"), the parties will use good-faith efforts to
resolve the matter in accordance with this Clause 11.4 prior to instituting any
legal proceeding in connection therewith; provided, however, that nothing herein
will require either party to forego or delay the institution of any proceeding
to seek equitable or injunctive relief to stop or prevent any breach of this
Agreement if it reasonably believes that it

                                                          CONFIDENTIAL TREATMENT

                                       28
<PAGE>

would be irreparably harmed by any delay in seeking such relief. If a dispute
occurs, either party may, by written notice to the other party, have such
dispute referred to their respective officers designated below (or their
respective designees) for attempted resolution by good faith negotiations within
*** after such notice is received. The original designated officers are:

     For LB: Rene Imwinkelried, Director and Head of Slough Site

     For Customer: Dr. Peter A. Thompson, MD, President and CEO.

     In the event the designated officers (or their respective designees) are
not able to resolve such dispute within such ***, or such other period of time
as the parties may mutually agree in writing, the parties shall have the right
to pursue any and all remedies at law and in equity. Notwithstanding the
foregoing, Disputes regarding nonconforming bulk Product under Section 5.9 above
will be referred first to the officers designated above and then, in the event
that such officers are unable to resolve the Dispute, to an independent expert
(acting as an expert and not as an arbitrator) to be appointed by agreement
between LB and the Customer or, in the absence of agreement, by the President
for the time being of the Association of the British Pharmaceutical Industry.
The costs of such independent expert shall be borne equally between LB and the
Customer. The decision of such independent expert shall be in writing and, save
for manifest error on the face of the decision, shall be binding on both LB and
the Customer.

     12. NOTICES

          12.1 Any notice or other communication to be given under this
Agreement shall be delivered personally or sent by facsimile transmission and
acknowledged by the intended recipient, or if facsimile transmission is not
available, by first class pre-paid post addressed as follows:

          If to Lonza Biologics to: Lonza Biologics plc
                                    228 Bath Road
                                    Slough
                                    Berkshire SL1 4DX
                                    England
                                    Facsimile: +44 1753 777001

          For the attention of:     ***

          If to the Customer to:    Trubion Pharmaceuticals, Inc.
                                    24014th Ave., Suite 1050
                                    Seattle, WA 98121
                                    USA
                                    Facsimile: +1-206-838-0503

          For the attention of:     Kendall M. Mohler, Ph.D.
                                    Senior Vice President, R & D

                                                          CONFIDENTIAL TREATMENT

                                       29

<PAGE>

or to such other destination as either party hereto may hereafter notify to the
other in accordance with the provisions of this Clause 12.

          12.2 All such notices or other communications shall be deemed to have
been served as follows:

               12.2.1 if delivered personally, at the time of such delivery;

               12.2.2 if sent by facsimile, upon receipt of the transmission
confirmation slip showing completion of the transmission;

               12.2.3 if sent by first class pre-paid post, upon receipt by the
addressee.

     13. MISCELLANEOUS

          13.1 Neither party shall be entitled to assign, transfer, charge or in
any way make over the benefit and/or the burden of this Agreement without the
prior written consent of the other which consent shall not be unreasonably
withheld or delayed, save that either party shall be entitled without the prior
written consent of the other to assign, transfer, charge, sub-contract, deal
with or in any other manner make over the benefit and/or burden of this
Agreement to an Affiliate or to any company with which the assigning party may
merge or to any company to which it may transfer its assets and undertakings.

          13.2 The text of any press release or other communication to be
published by or in the media concerning the subject matter of the Agreement
shall require the prior written approval of LB and the Customer, LB shall not
make use of Customer's name in any advertisement or promotional material or
customer list without in each case the prior written consent of Customer.
Consent to be given under this Clause 13.2 shall not be unreasonably withheld or
delayed. Notwithstanding anything in this Agreement seemingly to the contrary,
LB hereby consents to Customer's disclosure of LB's name to Customer's current
and potential employees, directors, shareholders, investors, partners, and
subcontractors.

          13.3 The Agreement embodies the entire understanding of LB and the
Customer and there are no promises, terms, conditions or obligations, oral or
written, expressed on implied, other than those contained in the Agreement, The
terms of the Agreement shall supersede all previous agreements (if any) which
may exist or have existed between LB and the Customer relating to the Services.

          13.4 The parties to this Agreement do not intend that any term hereof
should be enforceable by virtue of the Contracts (Rights of Third Parties) Act
1999 by any person who is not a party to this Agreement.

          13.5 No variation of or addition to this Agreement or any part thereof
shall be effective unless in writing and signed on behalf of both parties,
Notwithstanding the above the parties hereby confirm that amendments to the
Specifications shall be effective if reduced to writing

                                                          CONFIDENTIAL TREATMENT

                                       30

<PAGE>

and signed by the quality and/or regulatory representative of both parties,
which quality and/or regulatory representative shall be nominated from time to
time by each party. In the event of any conflict between the main body of this
Agreement and any Schedule, the terms of the main body of this Agreement shall
control.

          13.6 Each of the parties to this Agreement is an independent
contractor and nothing herein contained shall be deemed to constitute the
relationship of partners, joint venturers, nor of principal and agent between
the parties. Neither party shall hold itself out to third parties as purporting
to act on behalf of, or serving as the agent of, the other party.

          13.7 This Agreement and any amendment hereto may be executed in any
number of counterparts, each of which shall be deemed an original and all of
which shall constitute the same instrument This Agreement may be executed by
facsimile or original, and a facsimile signature shall be deemed to be and shall
be as effective as an original signature.

     14. LIMITATION OF LIABILITY; EXCLUSION OF CERTAIN DAMAGES

          14.1 LB's aggregate liability for direct damages arising out of or in
connection with this Agreement or the transactions contemplated hereby shall not
exceed the total maximum aggregate sum payable under this Agreement for the
Services, in accordance with Schedule 3 (Price and Terms of Payment) attached
hereto, except that the foregoing limitation shall not apply in the case of (a)
breach of Clause 8 (Confidentiality and Non-Use) by LB, (b) personal injury or
death, or (c) grossly negligent or intentionally wrongful acts or omissions of
LB. The foregoing limitation shall also not apply to claims arising under, or
LB's breach of, Clause 7.1 within Clause 7 (LB Warranties and Covenants and
Indemnity); provided, however, that LB's aggregate liability for direct damages
arising out of or in connection with claims arising under, or LB's breach of,
Clause 7.1 within Clause 7 (LB Warranties and Covenants and Indemnity), shall
not exceed the greater of (a) the total maximum aggregate sum payable under this
Agreement for the Services, in accordance with Schedule 3 (Price and Terms of
Payment) attached hereto, and (b) ***.

          14.2 NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INCIDENTAL,
PUNITIVE, INDIRECT, OR CONSEQUENTIAL DAMAGES OF ANY KIND, INCLUDING LOST
PROFITS, LOST DATA, LOST REVENUES, AND LOSS OF BUSINESS OPPORTUNITY, WHETHER OR
NOT THE OTHER PARTY WAS AWARE OR SHOULD HAVE BEEN AWARE OF THE POSSIBILITY OF
THESE DAMAGES, EXCEPT THAT THE FOREGOING LIMITATION SHALL NOT APPLY IN THE CASE
OF (a) BREACH OF CLAUSE 8 (CONFIDENTIALITY AND NON-USE) BY EITHER PARTY, (b)
PERSONAL INJURY OR DEATH, OR (c) GROSSLY NEGLIGENT OR INTENTIONALLY WRONGFUL
ACTS OR OMISSIONS.

          14.3 The terms of this Clause 14 shall survive the expiration or
termination for whatever reason of this Agreement.

                                                          CONFIDENTIAL TREATMENT

                                       31
<PAGE>

              [The remainder of this page intentionally left blank]

                                                          CONFIDENTIAL TREATMENT

                                       32

<PAGE>

     AS WITNESS the hands of the duly authorised representatives of the parties
hereto the day and year first above written.

Signed for and on behalf of
LONZA BIOLOGICS PLC                     /s/ Rene Imwinkelried
                                        ----------------------------------------
                                        Senior Vice President
                                        Head R & D Pharmaceuticals
                                        TITLE

Signed for and on behalf of
TRUBION PHARMACEUTICALS, INC.           /s/ Peter A. Thompson
                                        ----------------------------------------
                                        President & CEO
                                        TITLE

                                                          CONFIDENTIAL TREATMENT

                                       33

<PAGE>

                                   SCHEDULE 1
                         DEFINITIONS AND SPECIFICATIONS

DEFINITIONS

For the purpose of this document:

"Cell Line" shall mean the *** cell line created by the Customer expressing
Product.

"Product" shall mean the Small Modular ImmunoPharmaceutical (SMIP) produced by
the Cell Line known as TRU-015.

SPECIFICATIONS

1.1  EXAMPLE OF TYPICAL INITIAL SPECIFICATION FOR BULK PURIFIED PRODUCT

     (These examples are only examples of typical specifications, and shall not
be considered to be the specifications related to the Product)

<TABLE>
<CAPTION>
         TEST              METHOD   SPECIFICATION
         ----              ------   -------------
<S>      <C>               <C>      <C>
         CHARACTERISTICS
1.1.1    ***               ***      ***
1.1.2    ***               ***      ***
1.1.3    ***               ***      ***
1.1.4    ***               ***      ***
1.1.5    ***               ***      ***
1.1.6    ***               ***      ***
1.1.7    ***               ***      ***
1.1.8    ***               ***      ***
1.1.9    ***               ***      ***
1.1.10   ***               ***      ***
1.1.11   ***               ***      ***.
1.1.12   ***               -***     ***-
</TABLE>

1.2  EXAMPLE OF TYPICAL SPECIFICATION FOR BULK FERMENTER HARVEST

     (These examples are only examples of typical specifications, and shall not
be considered to be the specifications related to the Product)

<TABLE>
<CAPTION>
         TEST              METHOD   SPECIFICATIONS
         ----              ------   --------------
<S>      <C>               <C>      <C>

</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        1

<PAGE>

<TABLE>
<S>      <C>               <C>      <C>
1.2.1    ***               ***      ***
1.2.2    ***               ***      ***
1.2.3    ***               ***      ***
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        2

<PAGE>

1.3  FINAL BULK PRODUCT DISPOSITION

<TABLE>
<S>     <C>                           <C>
1.3.1   Final Formulation Buffer:     ***
1.3.2   Bottling of Bulk Product:
        1.3.2.1 Containers            ***
        1.3.2.2 Denominations         ***
                                      ***
1.3.3   Product Storage Conditions:   ***
1.3.4   Shipment Temperature:         ***
</TABLE>

1.4  SPECIFICATION FOR CELL BANKS

     STARTING MATERIAL DEFINITION

     An *** of a cryopreserved *** will be created from the Cell Line provided
by the Customer and stored in individual ampoules in liquid nitrogen
refrigerators.

     GENERAL *** SPECIFICATION

     In order for the *** to be accepted into LB's cGMP facility, the following
testing is required and the appropriate specifications achieved.

<TABLE>
<CAPTION>
        TEST   METHOD   SPECIFICATIONS
        ----   ------   --------------
<S>     <C>    <C>      <C>
1.4.1   ***    ***      ***
               ***
        ***    ***      ***
               ***
1.4.2   ***    ***      ***
1.4.3   ***    ***      ***
1.4.4   ***    ***      ***
1.4.5   ***    ***      ***
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        3

<PAGE>

                                   SCHEDULE 2
                                    SERVICES

2.   SERVICES

2.1  SUPPLY OF CUSTOMER MATERIALS AND CUSTOMER KNOW-HOW

     Prior to commencement of the Services at LB or, if appropriate, prior to
the commencement of the relevant Stage of the Services, the Customer shall
supply LB with the following:

     ***

                                                          CONFIDENTIAL TREATMENT

                                        1

<PAGE>

2.2  ACTIVITIES TO BE UNDERTAKEN BY LB

     ***

                                                          CONFIDENTIAL TREATMENT

                                        2

<PAGE>

                                   SCHEDULE 3
                           PRICE AND TERMS OF PAYMENT

1.0  PRICE

     In consideration for LB carrying out the Services as detailed in Schedule
     2, the Customer shall pay LB as follows:

***

                                                          CONFIDENTIAL TREATMENT

                                        3

<PAGE>

                                   SCHEDULE 3
                           PRICE AND TERMS OF PAYMENT

2.0  PAYMENT

     Payment by the Customer of the Price for each Stage shall be made against
     LB's Invoices that will be issued as follows:

     2.1  FOR STAGE 1

          *** upon commencement of Stage 1.
          *** upon issue of the deliverables for Stage 1 to the Customer.

     2.2  FOR STAGE 2

          *** upon commencement of Stage 2.
          *** upon issue of the deliverables for Stage 2 to the Customer.

     2.3  FOR STAGE 3

          *** upon commencement of Stage 3.
          *** upon issue of the deliverables for Stage 3 to the Customer.

     2.4  FOR STAGE 4

          *** upon commencement of Stage 4.
          *** upon issue of the deliverables for Stage 4 to the Customer.

     2.5  FOR STAGE 5

          *** upon commencement of Stage 5.
          *** upon issue of the deliverables for Stage 5 to the Customer.

     2.6  FOR STAGE 6

          *** upon commencement of Stage 6.
          *** upon issue of the deliverables for Stage 6 to the Customer.

     2.7  FOR STAGE 7

          *** upon commencement of Stage 7.
          *** upon issue of the deliverables for Stage 7 to the Customer.

     2.8  FOR STAGE 8

          *** upon ampoule thaw of each batch manufactured under Stage 8.
          *** upon issue of the certificate of analysis for each batch
          manufactured under Stage 8.

     2.9  FOR STAGE 9

          *** upon commencement of Stage 9.
          *** upon issue of the deliverables for Stage 9 to the Customer.

     2.10 FOR STAGE 10

          100% upon issue of each timepoint interim report and upon issue of the
          final report.

     2.11 FOR STAGE 11

          *** upon commencement of Stage 11.
          *** upon issue of the deliverables for Stage 11 to the Customer.

     2.12 FOR STAGE 12

                                                          CONFIDENTIAL TREATMENT

                                        4

<PAGE>

          *** upon commencement of Stage 12.
          *** upon issue of the deliverables for Stage 12 to the Customer.

     2.13 FOR STAGE 13

          *** upon commencement of Stage 13.
          *** upon issue of the deliverables for Stage 13 to the Customer.

     2.14 FOR STAGE 14

          100% upon issue of each timepoint interim report and upon issue of the
          final report.

                                                          CONFIDENTIAL TREATMENT

                                        5

<PAGE>

                                   SCHEDULE 4
                                QUALITY AGREEMENT

              [The remainder of this page intentionally left blank]

                                                          CONFIDENTIAL TREATMENT

                                        6
<PAGE>

                                QUALITY AGREEMENT

     This quality agreement ("Quality Agreement") is dated effective as of 8th
January 2004, and it defines the roles and responsibilities for the quality
operations between LONZA BIOLOGICS PLC, the registered office of which is at 228
Bath Road, Slough, Berkshire SL1 4DX, England (herein after referred to as
"LB"), and TRUBION PHARMACEUTICALS, INC., (formerly known as GENECRAFT, INC.) of
2401 4th Avenue, Suite 1050, Seattle, WA 98121, USA (herein after referred to as
the "Customer") with respect to manufacture of Customer's proprietary Small
Modular ImmunoPharmaceutical (SMIP) known as TRU-015 ("TRU-015") under that
certain development and manufacturing services agreement between the parties of
even date herewith (the "Services Agreement") in preparation for regulatory
filings and for human clinical use. When used in this Quality Agreement, the
term "Product" refers to TRU-015 and/or to the form of TRU-015 manufactured
under the Services Agreement, as the context requires.

     This Quality Agreement takes the form of a detailed list of activities
associated with the manufacture, testing and release of Product. Responsibility
for each activity is assigned to either the Customer or LB, or is assigned to
both the Customer and LB, and additional details are provided in the Services
Agreement and in the SOP's referred to in this Quality Agreement.

     This is the Quality Agreement that is referred to in the Services
Agreement. Capitalized terms used but not defined in this Quality Agreement
shall have the meaning given in the Services Agreement. This Quality Agreement
may be amended by written agreement of the parties. In the event of a conflict
between the Quality Agreement and the Services Agreement, the Services Agreement
shall control. This Quality Agreement may be executed in any number of
counterparts, each of which shall for all purposes be deemed an original and all
of which, taken together, shall constitute one and the same instrument. A
facsimile signature shall be deemed to be and shall be as effective as an
original signature.

     The responsibilities and rights of the parties under this Quality Agreement
are set forth below:

A.   OVERALL RESPONSIBILITIES

     This Quality Agreement outlines the responsibilities of the Customer and LB
with respect to the quality assurance of Product manufactured and supplied by LB
for the Customer under the terms of the Agreement.

     This Quality Agreement takes the form of a detailed list of activities
associated with the manufacture, testing and release of Product. Responsibility
for each activity is assigned to either the Customer or LB, or is assigned to
both the Customer and LB.

     This detailed list describes generic quality activities that would be
performed by both parties for Product used in clinical trail supply. The
specific services to be provided by LB will be set out in

                                                          CONFIDENTIAL TREATMENT

                                        1

<PAGE>

the Agreement (and any Amendments to the Agreement) on Price and other terms
acceptable to both parties.

     LB is responsible for ensuring that the quality requirements for Product
are as specified in the approved Product specification and that Product is
manufactured, tested and stored in accordance with current Good Manufacturing
Practices (cGMP) and all applicable US and EU regulations and ICH guidelines.

     The Customer is responsible for shipping and the final review, approval,
and release of product for use in the clinic. The Customer is responsible for
Product development, technical oversight, product specifications and regulatory
agency filings.

B.   SPECIFIC RESPONSIBILITIES

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
1.0  Organisation and Personnel       -    Ensure adequate number of personnel     -    Right to audit
                                           with appropriate training, skills,
                                           knowledge and experience to
                                           manufacture and test Product in and
                                           Equipment utilities, equipment,
                                           computerised systems and software are
                                           properly designed, validated and
                                           maintained in accordance with cGMP

2.0  Facilities, Utilities and        -    Ensure facilities, environment,         -    Right to audit
     Equipment                             utilities, equipment, computerised
                                           systems and software are properly
                                           designed, validated and maintained in
                                           accordance with cGMP

                                      -    Ensure Product is manufactured and      -    Right to audit
                                           tested only at sites as agreed with
                                           Customer

                                      -    Provide Customer with Drug Master       -    Include Drug Master File reference
                                           File reference that will allow US FDA        into regulatory submissions, as
                                           the ability to cross-reference other         appropriate
                                           products that are manufactured at
                                           LB's manufacturing and testing
</TABLE>

----------
(1)  Throughout the Quality Agreement, Customer's column includes the phrase
     "right to audit" - the use of this phrase in certain instances but not in
     others does not and shall not imply that Customer's audit rights pursuant
     to Clause 15 below are limited to those boxes where "right to audit"
     appears.

                                                          CONFIDENTIAL TREATMENT

                                        2

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           locations

                                      -    Provide Customer with documentation
                                           that no penicillin is manufactured or
                                           tested at site

3.0  Raw Materials for Process and    -    Source, test and release raw            -    Right to audit; right to review all
     Packaging of Product/Vendor           materials and primary packaging of           raw material specifications, grades
     Qualification Process                 appropriate quality for processing of        and vendors used in manufacture of
                                           Product                                      Product

                                                                                   -    Customer to provide LB with list of
                                                                                        critical raw materials used in
                                                                                        Customer process; update with changes
                                                                                        as necessary

                                      -    Propose and jointly agree               -    Right to approve vendor, grade and
                                           specifications, vendors and grade of         specifications of critical raw
                                           critical raw materials used in               materials used in Customer process,
                                           Customer process in accordance with          including excipients, and raw
                                           LB policy, with preference for               materials of animal or human origin
                                           non-animal and non-human derived raw
                                           materials

                                      -    Acknowledge and support Customer's
                                           goal not to use any raw materials of
                                           animal or human origin in the
                                           development of Customer process

                                      -    Retain representative samples           -    Right to audit

4.0  Cell Banks                       -    Prepare, characterise and store cell    -
                                           bank(s) if requested by Customer

                                      -    Jointly agree on testing                -    Jointly agree on testing
                                           specifications and test methods to           specifications and test methods to
                                           enable release of cell banks for use         enable Product manufactured from cell
                                           in LB's multi-product manufacturing          banks to be used in the clinic
                                           facility

                                      -    Perform stability testing of cell       -    Right to audit
                                           bank(s) if requested by Customer and
                                           share data with Customer

                                      IF CELL BANK SUPPLIED BY CUSTOMER

                                      -    Review and approve characterisation     -    Supply cell bank characterisation
                                           data. Store working stock or cell            data for review and approval.
                                           bank                                         Transfer cell bank (or portion
                                                                                        thereof) to LB
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        3

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                      -    Provide shipping validation data if     -    Right to audit
                                           requested by Customer

                                      IN ALL CASES

                                      -    Provide inventory levels periodically
                                           upon request by Customer

5.0  Production Specification         -    With the Customer determine and         -    With LB determine and approve the
                                           approve the following Product                following Product specification(s) as
                                           specification(s) as required:                required:

                                           -    Drug substance (including               -    Drug substance (including
                                                testing performed on                         testing performed on
                                                fermenter contents for                       fermenter contents for
                                                adventitious agents)                         adventitious agents)

                                           -    Drug product                            -    Drug product

                                           -    Bulk placebo                            -    Bulk placebo

                                           -    Filled placebo                          -    Filled placebo

6.0  Production and Process Control   -    Make available for review by Customer   -    Right to review
                                           documents relating to facility,
                                           equipment, Process and test methods,
                                           and GMP systems

                                      -    Jointly review and approve Process      -    Jointly review and approve Process
                                           descriptions                                 descriptions

                                      -    Define and perform an in-process        -    Agree in-process testing strategy
                                           control and testing program

                                      -    Using LB templates prepare master       -    Right to review and comment on master
                                           batch records for each processing            batch records
                                           step and provide to Customer for
                                           review and comment. Retain final
                                           master batch record on site at LB

                                      -    Designate unique batch numbers for      -    Right to audit
                                           raw materials, process materials and
                                           Product

                                      -    Manufacture of Product in accordance    -    Right to audit
                                           with Product Specifications, cGMP
                                           standards, batch records, in-process    -    Relevant sections of Customer's
                                           controls and in-process                      regulatory submissions to be made
                                           specifications                               available to LB as appropriate

                                      -    Ensure QA representatives on-site or    -    Right to audit
                                           available at all times during
                                           manufacture and testing of Product
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        4

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                      -    Permit Customer's person on plant to    -    Right to designate 1 of its employees
                                           be present in LB's facility during           or consultants as Customer's person
                                           normal business hours to observe the         on plant, to be present in LB's
                                           Runs and observe LB's performance, at        facility during normal business hours
                                           times and for durations to be agreed.        to observe the Runs and observe LB's
                                           While at LB's facility, Customer's           performance, at times and for
                                           representative shall comply with all         durations to be agreed. While at LB's
                                           LB's applicable policies and                 facility, Customer's representative
                                           procedures, and, at LB's option,             shall comply with all of LB's
                                           shall be escorted by LB personnel            applicable policies and procedures,
                                                                                        and, at LB's option, shall be
                                                                                        escorted by LB personnel

                                      -    Perform Product changeover testing of   -    Review and comment on LB's policy for
                                           Product-contacting equipment in              Product changeover testing of
                                           accordance with LB policy                    Product-contacting equipment

7.0  Product Storage, Labeling and    -    Store, label and package the Product    -    Right to audit
     Packaging Prior to Shipment           (including samples) as defined in the
                                           Product Specification                   -    Provide information on shipping
                                                                                        requirements

8.0  Shipment Requirements            -    Ship Product on behalf of Customer to   -    Jointly agree with LB on process for
                                           locations designated by Customer in          shipping requirements
                                           accordance with jointly agreed
                                           process for shipping requirements       -    Right to audit

                                                                                   -    Acknowledge receipt of Product

                                      -    Provide shipping validation data for    -    Right to audit
                                           Product if requested by Customer

9.0  Laboratory Controls (QC)         -    Perform Product release testing         -     Right to audit
                                           against Product Specifications

                                      -    Jointly agree on SOP's describing       -    Jointly agreed on SOP's describing
                                           Product-specific analytical testing          Product-specific analytical testing
                                           methods                                      methods

                                                                                   -    Provide LB with Product-specific
                                                                                        information as it relates to sample
                                                                                        storage, handling and testing
                                                                                        requirements

                                      -    Retesting, where required, will be      -    Review and comment on LB retest
                                           performed in accordance with LB's            procedure. Review OOS reports;
                                           retest procedure. Out of                     comment on corrective and
                                           specification (OOS) Product                  preventative actions
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        5

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           release testing results will be
                                           notified to the Customer as soon as
                                           possible within 3 business days of
                                           the OOS being confirmed

                                      -    Send samples to Customer for            -    Perform Product potency testing and
                                           additional testing (including potency        provide data to LB; such data will be
                                           testing) in accordance with jointly          provided for LB's information only
                                           approved SOP                                 and not for inclusion into LB's
                                                                                        information only and not for
                                                                                        inclusion into LB's Certificate of
                                                                                        Analysis. Customer to create
                                                                                        Certificate of Analysis for potency
                                                                                        testing results. [Note from Trubion:
                                                                                        This text to clarify that Trubion is
                                                                                        performing the potency testing and
                                                                                        providing the results to LB 'FOR
                                                                                        INFORMATION']

                                      -    Retain representative samples of bulk   -    Right to audit
                                           Product from each batch in accordance
                                           with LB SOP

                                      -    If requested by Customer, provide       -    Right to receive copies of raw data
                                           copies of raw data and testing               and testing records
                                           records

                                      -    Take additional representative          -    Request additional samples to be
                                           samples if requested and ship to             shipped as required
                                           Customer

                                      -    Prepare and characterise Product        -    Jointly approve Product reference
                                           reference standard in accordance with        standard Protocol
                                           jointly agreed Protocol, if requested
                                           by Customer                             -    Right to audit

                                      -    Jointly approve Product reference       -    Jointly approved Product reference
                                           standard report                              standard report

10.0 Use of Contract Testing          -    Qualify Contract Testing Laboratories   -    Right to jointly audit
     Laboratories                          for Product release testing in
                                           accordance with LB policy

                                      -    Notify Customer of Contract Testing     -    Consent or reject to the proposed use
                                           Laboratories intended to be used for         of Contract Testing Laboratories
                                           Product release testing

                                      -    Facilitate audit by Customer if         -    Right to audit
                                           requested from time to time
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        6

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                      -    If not prohibited by Contract Testing   -    Right to request, receive and use
                                           Laboratory, provide Customer with            copies of LB's audits of Contract
                                           copies of LB's audits of Contract            Testing Laboratories when possible,
                                           Testing Laboratories when possible,          unless prohibited by Contract Testing
                                           if requested                                 Laboratories

11.0 Product Release and Lot Review   -    Review batch record for compliance      -    Right to review completed and
                                           with cGMP, manufacturing controls,           reviewed Product batch records
                                           and with the Product Specifications

                                      -    Provide Customer with a copy of the     -    Right to review
                                           Process documentation including, main
                                           operational steps from the completed
                                           batch record. This will include
                                           Product analysis, a summary of batch
                                           related deviations and environmental
                                           monitoring summaries, as well as
                                           process data, as requested

                                      -    If requested by Customer, send full     -    Right to request and receive full
                                           copies of actual deviations                  copies of actual deviations

                                      -    Prepare manufacturer's Certificate of   -    Prepare Certificate of Analysis and
                                           Analysis, including related                  Certificate of Compliance for release
                                           Certificate of Compliance                    of product for use in human clinical
                                                                                        trials

                                      -    Release or reject Product               -    Release of reject Product for use in
                                                                                        human clinical trials

12.0 Deviations and Failed Run        -    Initiate investigations, evaluate and   -    Right to audit
     Investigations and Reports            define follow up actions and final
                                           approval of deviations and failure
                                           investigations

                                      -    Notify Customer of all significant      -    Review significant deviations;
                                           deviations immediately and within at         comment on corrective and
                                           least 3 business days of the event           preventative actions
                                           being assigned as significant, and
                                           send Customer the related
                                           documentation. (A significant
                                           deviation is defined in standard
                                           operating procedure 3150)

                                      -    Notify Customer of failed runs          -    Review failure investigation report
                                           immediately and within at least 3            and comment on corrective and
                                           business days of failure being               preventative actions
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        7
<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           identified

                                      -    Immediately and within at least 3
                                           business days of event being
                                           identified, notify Customer of any
                                           events which may impact batches
                                           previously shipped or released

13.0 Change Control Procedures        -    Jointly agree on SOP for change         -    Jointly agree SOP for change control
                                           control procedures between the 2             procedures between the 2 companies
                                           companies that describes the intended        that describes the intended use of
                                           use of each company's independent            each company's independent change
                                           change control system                        control systems

                                      CUSTOMER PROPOSED CHANGES

                                      -    Process Product-specific change         -    Propose Customer Product-specific
                                           through change control and notify            changes and provide rationale in
                                           Customer of change approval. If              writing
                                           change rejected, discuss reasons for
                                           rejection with Customer

                                      -    Approve proposed Product-specific
                                           changes prior to implementation

                                      LB PROPOSED CHANGES

                                      -    Proposed Product-specific changes and   -    Process Product-specific change
                                           provide rationale for change to              through change control and notify LB
                                           process descriptions; test methods;          of change approval. If change
                                           sampling plans; specifications for           rejected, discuss reasons for
                                           key raw materials (animal and / or           rejection with LB
                                           human derived raw materials,
                                           chromatography resins and final         -    Approve proposed Product-specific
                                           formulation excipients); Product             changed prior to implementation
                                           specification(s) and stability
                                           programme, in-process controls and
                                           other key processing steps

                                      -    Inform Customer of changes to key       -    Right to audit
                                           personnel as identified in Appendix 1

                                      -    Inform Customer of changes to major     -    Right to audit
                                           items of equipment, premises and
                                           utilities used for manufacture of
                                           Product

                                      ALL CHANGES

                                      -    With Customer define strategy for       -    With LB define strategy for notifying
                                                                                        change to Regulatory
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        8

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           notifying change to Regulatory Agency        Agency as appropriate (see Section
                                           as appropriate (see Section 20.0,            20.0, below, Regulatory Submissions)
                                           below, Regulatory Submissions)

                                      -    Inform Customer of Product batches      -    Ensure Product is not distributed
                                           manufactured with the change until           until Regulatory approval obtained,
                                           regulatory approval obtained, if             if required
                                           required

                                      -    Cooperate with Customer in connection   -    Cooperate with LB in connection with
                                           with change controls; respect                change controls; respect LB's change
                                           Customer's change controls, and, as          controls, and, as appropriate, use it
                                           appropriate, use it to initiate LB's         to initiate Customer's change
                                           change controls                              controls

14.0 Reprocessing / Rework            -    Processing to be performed in           -    Review and comment on LB's
                                           accordance with LB SOP. With Customer        reprocessing / rework SOP; with LB
                                           agree on reprocessing / rework               agree on reprocessing / rework
                                           procedures, where possible prior to          procedures, where possible prior to
                                           execution                                    execution

                                      -    Provided documented reason and          -    Right to audit
                                           justification for reprocessing /
                                           rework event

                                      -    With the Customer agree on the          -    With LB agree the appropriate testing
                                           appropriate testing required prior to        required prior to Product release
                                           Product release

15.0 Audit                            -    Permit Customer representatives         -    Provide reasonable notice of
                                           access as reasonably required to             intention to audit
                                           conduct a cGMP compliance audit,
                                           including access to warehousing,        -    Right to 2 standard cGMP compliance
                                           manufacturing areas, laboratories,           audits per year, plus right to
                                           and manufacturing records and                additional "for cause" audits
                                           documents, including SOPs (unless
                                           they contain specific LB proprietary    -    Right to audit each batch record
                                           information eg media formulations),
                                           and personnel, for audit purposes.      -    Hold an exit meeting to discuss
                                           Customer representatives to be               observations
                                           accompanied at all times by LB
                                           personnel                               -    Provide an audit report within 30
                                                                                        days of completion of audit
                                      -    Two standard cGMP compliance audits
                                           permitted per year, with an audit not
                                           to exceed 3 working days and 2 groups
                                           of auditors. Additionally the
                                           Customer may
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                        9

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           request "for cause" audits to address
                                           production of Product quality issues

                                      -    One 2 day audit for each batch record
                                           if requested by Customer

                                      -    Allow the Customer to observe
                                           operations related to Product
                                           manufacturing and testing providing
                                           other Customer's confidentiality is
                                           respected

                                      -    Provide a written response to all
                                           audit findings that require
                                           corrective action within 30 days of
                                           receipt of the audit report. Response
                                           to include expected timelines

16.0 Product Complaints and Recall    -    Respond to requests for data to         -    Receive and investigate Product
                                           assist Customer in their                     complaints and instigate Product
                                           investigation. Agree a time scale for        recall as appropriate
                                           response

17.0 Batch Records                    -    Retain records associated with          -    Right to audit
                                           manufacture and testing records of
                                           Product including records associated
                                           with the inspection and release of
                                           raw materials and primary packaging
                                           components of the Product for 5 years
                                           from the date of manufacture of
                                           Product. Date of manufacture is
                                           defined as the date Product is
                                           dispensed in to the bulk product
                                           container)

                                      -    Notify Customer of intent to destroy    -    Customer to approve destruction or
                                           records with option to send records          request receipt of records
                                           to Customer

18.0 Process Validation /             -    With Customer define process            -    With LB define process validation
     Stability Studies                     validation plans for Product                 plans for Product including
                                           including analytical validation and          analytical validation and stability
                                           stability studies                            studies

                                      WHERE PROCESS VALIDATION IS PERFORMED BY
                                      LB

                                      -    Provide Customer with Product           -    Approve Product specific validation
                                           specific validation protocol(s) for          protocol(s) including stability
                                                                                        protocols
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                       10

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           approval prior to execution

                                      -    Provide Customer with draft Product     -    Review and comment on Product
                                           specific validation report(s) for            specific validation report(s)
                                           review and comment                           including stability reports

                                      -    Issue Customer with copy of final       -
                                           Product specific validation report(s)

                                      WHERE PROCESS VALIDATION IS PERFORMED BY
                                      CUSTOMER

                                      -    Incorporate specifications in cGMP      -    Provide LB with process validation
                                           documentation and regulatory                 reports
                                           submissions

19.0 Regulatory Agency Inspection     GMP INSPECTIONS

                                      -    Inform Customer of Regulatory Agency    -    For Regulatory Agency inspections or
                                           inspections or regulatory action             regulatory action affecting Product,
                                           affecting manufacture, testing or            provide assistance when requested by
                                           storage of Product                           LB

                                      -    Notify Customer of inspection           -    Comment on proposed inspection
                                           observations (including Deficiency           responses to observations relevant to
                                           Letters) affecting the Product,              Product
                                           process or systems relating to the
                                           Product

20.0 Regulatory Submissions           WHERE A DATA PACK IS PROVIDED BY LB TO
                                      SUPPORT CUSTOMER'S CLINICAL TRIAL
                                      APPLICATION

                                      INITIAL APPLICATION, AMENDMENTS AND
                                      RESPONSES TO QUESTIONS

                                      -    Provide Customer with data pack         -    Prepare and provide LB with copy of
                                           covering activities performed by LB          relevant sections of clinical trial
                                                                                        application for review and comment
                                                                                        prior to submission to Regulatory
                                                                                        Agency

                                      -    Review and comment on relevant          -    Provide LB with copy of relevant
                                           sections of clinical trial                   sections as submitted to Regulatory
                                           application                                  Agencies

                                      TELECONFERENCES AND MEETINGS WITH THE
                                      REGULATORY AGENCIES

                                      -    Attend teleconferences and meetings     -    Arrange for LB personnel to have
                                           between the Customer and Regulatory          option to attend teleconferences and
                                           Agencies arranged                            meetings between Customer
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                       11

<PAGE>

<TABLE>
<CAPTION>
                                                                    RESPONSIBILITIES AND RIGHTS
                                      ---------------------------------------------------------------------------------------
                ITEM                                      LB                                       CUSTOMER(1)
-----------------------------------   ------------------------------------------   ------------------------------------------
<S>                                   <C>                                          <C>
                                           to specifically discuss topics               and Regulatory Agencies to
                                           relating to LB's responsibilities            specifically discuss topics relating
                                                                                        to LB's responsibilities
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                       12

<PAGE>

QUALITY APPROVAL

LONZA BIOLOGICS PLC

Name: /s/ Rene Imwinkleried             Signature: /s/ Rene Imwinkleried
      -------------------------------              -----------------------------
Title: Senior Vice President            Date: (illegible) Apr 2004

TRUBION PHARMACEUTICALS INC.

Name: Peter A. Thompson, MD             Signature: /s/ Peter Thompson
      -------------------------------              -----------------------------
Title: President & CEO                  Date: 4/23/2004

                                                          CONFIDENTIAL TREATMENT

                                       13
<PAGE>

                       APPENDIX 1 TO THE QUALITY AGREEMENT

<TABLE>
<CAPTION>
CUSTOMER                              LONZA
--------                              -----
<S>                                   <C>
SENIOR VICE PRESIDENT,                HEAD OF LONZA CONTRACT MANUFACTURING:
RESEARCH AND DEVELOPMENT:
Kendall M Mohler PhD                  Mr Rene Imwinkleried
Senior Vice President                 Head of Lonza Contract Manufacturing
Research and Development              Lonza Biologics
Trubion Pharmaceuticals Inc           228 Bath Road
2401 Fourth Avenue, Suite 1050        Slough SL1 4DX
Seattle, WA 98121                     UK
USA
Tel:+1 206 838 0514                   Tel:+44 1753 777082
Fax: +1 206 838 0503                  Fax: +44 1753 716644
Email: kmoh1er@trubion.com            Email: Rene.lmwinkleried@Lonza,com

HEAD OF QUALITY:                      HEAD OF QUALITY:
Sally R Gould                         Mrs Eleanor Taaffe
Senior Director, Regulatory Affairs   Head of Quality and Regulatory Affairs
Trubion Pharmaceuticals Inc           Lonza Biologics
2401 Fourth Avenue, Suite 1050        228 Bath Road
Seattle, WA 98121                     Slough SL1 4DX
USA                                   UK
Tel:+1206 838 0510                    Tel:+44 1753 777067
Fax:+1 206 838 0503                   Fax;+44 1753 777001
Email: sqould@trubion.com             Email: Eleanor.Taaffe@Lonza.com

HEAD OF MANUFACTURING:                DIRECTOR OF MANUFACTURING, UK:
Dale H Scott                          Dr Michael E Brown
Vice President, Development           Head of Manufacturing
Trubion Pharmaceuticals Inc           Lonza Biologics
2401 Fourth Avenue, Suite 1050        228 Bath Road
Seattle, WA 98121                     Slough SL1 4DX
USA                                   UK
Tel: +1 206 838 0513                  Tel: +44 1753 777000
Fax: +1 206 838 0503                  Fax: +44 1753 777001
Email: dscott@trubion.com             Email: Mike.Brown@Lonza.com

QUALITY CONTROL MANAGER:              QUALITY CONTROL MANAGER:
Raj Dua PhD                           Dr Steve Flatman
Director, Product Development         Head of QC and Analytical
Trubion Pharmaceuticals Inc           Lonza Biologics
2401 Fourth Avenue, Suite 1050        228 Bath Road
Seattle, WA 98121                     Slough SL1 4DX
USA                                   UK
Tel: +1 206 838 0512                  Tel: +44 1753 777000
Fax: +1 206 838 0503                  Fax: +44 1753 777001
Email: rdua@trubion.com               Email: Steve.Flatman@Lonza.com
</TABLE>

                                                          CONFIDENTIAL TREATMENT

                                       14

<PAGE>

                                   SCHEDULE 5

                                  SPECIAL TERMS

 OUTLINE OF TERMS FOR THE TECHNOLOGY TRANSFER OF THE PROCESS FOR MANUFACTURE OF
                     PRODUCT TO CUSTOMER OR TO A THIRD PARTY

     This Schedule 5 is the Schedule that is referred to in Clause 9.9 of the
Development and Manufacturing Services Agreement ("Development and Manufacturing
Services Agreement") between LONZA BIOLOGICS PLC as "LB" and TRUBION
PHARMACEUTICALS, INC. as "Customer" related to the Technology Transfer of the
Process to Customer or a third party. This Schedule 5 sets forth some additional
commercial terms for any Technology Transfer. All capitalized terms used but not
defined in this Schedule 5 shall have the meanings given in the Development and
Manufacturing Services Agreement.

     ***

                                                          CONFIDENTIAL TREATMENT

                                       1

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