Exhibit 10.1

LICENSE AGREEMENT

BETWEEN

BRISTOL-MYERS SQUIBB

-i-

-ii-

-iii-

EXHIBITS

-iv-

LICENSE AGREEMENT

THIS LICENSE AGREEMENT (this “Agreement”) dated as of March 30, 1998 by and between Bristol-Myers Squibb Company, a corporation duly organized and existing under the laws of the State of Delaware, having offices at P.O. Box 4000, Route 206 and Province Line Road, Princeton, New Jersey 08543-4000, for and on behalf of itself and its Affiliates (“BMS”), and Seattle Genetics, Inc., a corporation duly organized and existing under the laws of the State of Delaware, having offices at 22215 26th Avenue, SE, Bothell, Washington 98021 (“SGI”).

PRELIMINARY STATEMENTS

A. BMS has developed, is the owner of and has all right, title and interest in and to certain valuable technology, including know-how and patents or patent applications, for the treatment of diseases and conditions in humans.

B. In addition, BMS has obtained licenses with respect to certain other valuable technology, including know-how and patents or patent applications, for the treatment of diseases and conditions in humans by entering into: (i) that certain Agreement with the University of Washington (the “Washington Agreement”), dated as of January 26, 1989; (ii) that certain License Agreement, with Ixsys, Inc. (the “Ixsys Agreement”), dated as of June 8, 1993; and (iii) that certain Semi-Exclusive License Agreement with Enzon, Inc. (the “Enzon Agreement”), dated as of September 30, 1993.

C. SGI is interested in developing and commercializing such technology and desires to obtain a license from BMS to manufacture, market and sell products using such technology in the Territory.

D. BMS is willing to grant such license to SGI on the terms and conditions set forth in this Agreement.

NOW, THEREFORE, in consideration of the foregoing Preliminary Statements and the mutual covenants and agreements of the Parties contained in this Agreement, the Parties agree as follows:

1. DEFINITIONS .

As used in this Agreement, the following terms will have those meanings set forth in this Section 1 unless the context dictates otherwise.

1.1 “ Affiliate ”, with respect to any Party, shall mean any Person controlling, controlled by, or under common control with, such Party. For these purposes, “control” shall refer to (a) the possession, directly or indirectly, of the power to direct the management or policies of a Person, whether through the ownership of voting securities, by contract or otherwise or (b) the ownership, directly or indirectly, of at least 50% of the voting securities or other ownership interest of a Person.

1.2 “ BMS In-Licenses ” shall mean the Washington Agreement, the Ixsys Agreement and the Enzon Agreement, collectively.

1.3 “ Effective Date ” shall have the meaning assigned thereto in Section 5.1.

1.4 “ Enzon Field ” shall mean proteins that derive their therapeutic activity by their binding affinity for the Lewis-Y antigen or that compete with monoclonal antibody BR96 for binding to the Lewis-Y antigen, for therapeutic use only, excluding, without limitation, the areas set forth in Exhibit B.

1.5 “ Enzon Patents ” shall have the meaning assigned thereto in Exhibit A.

1.6 “ Enzon Product ” shall mean a Product covered by the Licensed Technology relating to the Enzon Patents in the Enzon Field that is an SCA Protein (as such term is defined in the Enzon Agreement) the manufacture, composition or use of which in a country in the Territory, but for the license to BMS under the Enzon Agreement and the sublicense to SGI hereunder with respect to the Enzon Licensed Technology, would constitute an infringement of one or more Valid Claims of the Enzon Patents.

1.7 “ FDA ” shall mean the U.S. Food and Drug Administration, or the successor thereto.

1.8 “ Field ” shall have the meaning assigned thereto in Section 4.1(d).

1.9 “ First Commercial Sale ” shall mean, with respect to any Product, the first sale for use or consumption by the general public of such Product in a country in the Territory after all required marketing and pricing approvals have been granted, or otherwise permitted, by the governing health authority of such country. “First Commercial Sale” shall not include the sale of any Product for use in clinical trials or for compassionate use.

1.10 “ Generic Product ” shall mean, on a country-by-country basis, a Product: (i) the manufacture, use or sale of which is not covered by a Valid Claim in such country, and (ii) that is also marketed by an unlicensed Third Party or Parties in such country, which Third Party or Parties have, in the aggregate, at least 20% of the unit volume of sales for such Product in any calendar quarter in such country, as measured by IMS.

1.11 “ Improvement ” shall mean any new or useful invention, process or improvement, patentable or unpatentable, relating to or arising from the Licensed Technology, conceived or first reduced to practice or demonstrated to have utility by either Party, its Affiliates or sublicensees during the term of this Agreement, including, without limitation, any Products developed and marketed by SGI, its Affiliates or sublicensees.

1.12 “ IND ” shall mean an investigational new drug application filed with the FDA.

1.13 “ Ixsys Field ” shall mean the in vivo diagnosis or treatment of solid tumors in humans through the use of one or more antibodies.

-2-

1.14 “ Ixsys Patents ” shall have the meaning assigned thereto in Exhibit A .

1.15 “ Ixsys Product ” shall mean a Product covered by the Licensed Technology relating to the Ixsys Patents in the Ixsys Field that is (i) a diagnostic product, containing one or more Program Materials (as such term is defined in the Ixsys Agreement), for use in the in vivo detection of solid tumors in humans, or (ii) the final dosage formulation of a product incorporating pharmaceutical compositions containing Program Materials for use in the treatment of solid tumors in humans, regardless of the route of administration.

1.16 “ Know-How ” shall mean any and all technical data, information, material and other know-how, if any, currently owned, developed or acquired by BMS that (i) arise from the Residual Program, or (ii) are necessary or useful to practice the Patents.

1.17 “ Licensed Technology ” shall mean the Patents and antibodies set forth in Exhibit A , and, with respect to each Patent, the Know-How that is necessary or useful to practice such Patent, collectively. When no Patent(s) is specified, “Licensed Technology” shall mean all of the Patents, antibodies and Know-How, collectively.

1.18 “ Major Market ” shall mean each of France, Germany, Japan, Italy, Spain, the United Kingdom and the United States.

1.19 “ Net Sales ” shall mean, with respect to any Product, the gross amount invoiced for such Product by SGI, its Affiliates, and sublicensees to Third Parties, less deductions for: (i) trade, quantity and/or cash discounts, allowances and rebates (including, without limitation, promotional or similar allowances) actually allowed or given; (ii) freight, postage, shipping, insurance and transportation expenses and similar charges (in each instance, if separately identified in such invoice); (iii) credits or refunds actually allowed for rejections, defects or recalls of such Product, outdated or returned Product, or because of rebates or retroactive price reductions; and (iv) sales, value-added, excise taxes, tariffs and duties, and other taxes directly related to the sale, to the extent that such items are included in the gross invoice price (but not including taxes assessed against the income derived from such sale). Such amounts shall be determined from the books and records of SGI, its Affiliates or its sublicensees, maintained in accordance with the reasonable accounting principles used by such entity, consistently applied.

In the event that a Product is sold as part of a Combination Product (as defined below), the Net Sales from the Combination Product, for the purposes of determining royalty payments, shall be determined by multiplying the Net Sales of the Combination Product (calculated using the standard Net Sales definition) during the applicable royalty reporting period by the fraction A/A+B, where A is the average sale price of the Product when sold separately in finished form and B is the average sale price of the other product(s) included in the Combination Product when sold separately in finished form, in each case during the applicable royalty reporting period or, if sales of both the Product and the other product(s) did not occur in such period, then in the most recent royalty reporting period in which sales of both occurred. In the event that such average sale price cannot be determined for both the Product and all other product(s) included in the Combination Product, Net Sales for the purposes of determining royalty payments shall be calculated by multiplying the Net Sales of the Combination Product (calculated using the

-3-

standard Net Sales definition) by the fraction C/C+D, where C is the fair market value of the Product and D is the fair market value of all other pharmaceutical product(s) included in the Combination Product. In such event, SGI shall in good faith make a determination of the respective fair market values of the Product and all other pharmaceutical products included in the Combination Product, and shall notify BMS of such determination and provide BMS with data to support such determination. BMS shall have the right to review such determination and supporting data, and to notify SGI if it disagrees with such determination.

As used above, the term “Combination Product” shall mean any pharmaceutical product which comprises the Product and any other active compounds and/or ingredients.

1.20 “ Party ” shall mean BMS or SGI and, when used in the plural, shall mean BMS and SGI.

1.21 “ Patents ” shall mean all patents and patent applications throughout the Territory, and any substitutions, extensions, renewals, continuations, continuations-in-part, divisions, patents-of-addition and/or reissues or extensions thereof, which (i) are at present owned or controlled by BMS and are set forth in Exhibit A , or (ii) are owned or controlled by SGI or jointly by BMS and SGI, as the case may be, and cover any Improvement.

1.22 “ Person ” shall mean any natural person, corporation, firm, business trust, joint venture, association, organization, company, partnership or other business entity, or any government or any agency or political subdivision thereof.

1.23 “ Product ” shall mean any pharmaceutical formulation developed by SGI, its Affiliates or sublicensees during the term of this Agreement, the manufacture, use or sale of which is either: (i) based upon or derived from any of the Know-How; or (ii) covered by one or more Patents and, but for this Agreement, would constitute an infringement of a Valid Claim thereof. “Product” shall include Residual Product.

1.24 “ Research Program ” shall have the meaning assigned thereto in Section 5.2(f).

1.25 “ Residual Product ” shall mean any Product, the manufacture, use or sale of which is based upon or derived from any of the Residual Program Licensed Technology.

1.26 “ Residual Program ” shall have the meaning assigned thereto in Section 5.2(f).

1.27 “ Results ” shall mean any and all technical data, information, material and other know-how, whether patentable or not, including but not limited to analytical methodology, chemical, toxicological, pharmacological and clinical data, formulae, procedures, drafts and/or protocols, techniques, and results of experimentation and testing, developed or acquired by SGI, its Affiliates or sublicensees during the term of this Agreement which relate to the Licensed Technology, except Improvements. “Results” shall include data and information generated for the purpose of obtaining marketing approvals of the Products in any country in the Territory. The Results shall be owned by SGI.

-4-

1.28 “ Royalty Term ” shall mean, with respect to each Product in each country in the Territory, the period of time commencing on the Effective Date and ending on the date that is the latest of (i) 10 years from the date of the first Commercial Sale of such Product in such country, (ii) the expiration of the last to expire of the Valid Claims necessary for the manufacture, use and sale of such Product in such country, or (iii) with respect only to the Licensed Technology that relates to, or is necessary or useful to practice, the Washington Patents, the twelfth anniversary from the First Commercial Sale of Unpatented Product (as such term is defined in the Washington Agreement).

1.29 “ Territory ” shall mean the world.

1.30 “ Third Party ” shall mean any Person who or which is neither a Party nor an Affiliate of a Party.

1.31 “ Valid Claim ” shall mean a claim of any Patent which has not been held invalid or unenforceable by final decision of a court or other governmental agency of competent jurisdiction, unappealable or unappealed within the time allowed for appeal, and which is not admitted to be invalid or unenforceable through reissue, disclaimer or otherwise.

1.32 “ Washington Patents ” shall have the meaning assigned thereto in Exhibit A .

1.33 “ Washington Product ” shall mean a Product covered by the Licensed Technology relating to the Washington Patents that (i) the manufacture, use or sale of which would, but for the license to BMS under the Washington Agreement and the sublicense to SGI hereunder with respect to the Washington Licensed Technology, infringe a Valid Claim of the Assigned Patent Rights (as such term is defined in the Washington Agreement), or (ii) is not covered by such Assigned Patent Rights which contains antibody G28-5, fragments of antibody G28-5, a chimeric antibody made using antibody G28-5 or the Hybridoma (as such term is defined in the Washington Agreement), or fragments of such chimeric antibody.

2. EXCHANGE OF DATA AND MATERIALS .

2.1 Licensed Technology . As soon as practicable after the Effective Date, but in any event within 90 days thereafter, BMS shall deliver to SGI copies of all data, studies and materials comprising the Licensed Technology in BMS’s possession then reasonably available. During the term of this Agreement, BMS shall deliver to SGI copies of all material clinical data that relate to the Licensed Technology that come into EMS’s possession after the Effective Date. BMS shall have no obligation to provide any scientific, technical or other consulting or assistance of any kind to SGI with respect to the Licensed Technology.

2.2 Transfer of INDs . Promptly after the Effective Date, but in any event within 90 days thereafter, EMS shall transfer to SGI ownership of all INDs and other regulatory filings, if any, filed by BMS with respect to any products based upon, derived from or related to any of the Know-How or covered by one or more Patents. In addition, within 10 days after the Effective Date, BMS shall deliver to the FDA a letter transferring to SGI sponsorship of BMS’s BR96-

-5-

sFv-PE4O program. All INDs and other regulatory filings filed with respect to any Products after the Effective Date shall be owned by SGI.

2.3 Supply of Materials by SGI . Within 14 days after BMS’s request therefor, SGI will supply BMS with samples of any materials previously transferred to SGI by BMS. BMS shall be responsible for, and pay within 60 days after receipt of an invoice therefor, all of the reasonable out-of-pocket costs incurred by SGI in connection with the shipment of such samples.

2.4 Exceptions and Limitations . All of the information exchanged by the Parties pursuant to this Section 2 shall be deemed to be Confidential Information and shall be subject to the confidentiality provisions of Section 12.

3. DEVELOPMENT AND COMMERCIALIZATION .

3.1 Development Obligations . Subject to Section 3.5, SGI shall, at its own expense, use all commercially reasonable efforts, consistent with the efforts of companies of comparable size and financial resources as SGI, to develop Products, which efforts shall include the performance of all studies necessary to obtain approval for each indication of such Products from governmental agencies in all Major Markets in the Territory where governmental approval is necessary in order to market Products in such countries. During the 18-month period commencing on the Effective Date, such efforts also shall include the activities set forth in Section 13.2(u).

3.2 Conduct of Development by SGI . During the term of this Agreement, SGI shall:

(a) undertake its development obligations, as set forth in this Agreement, and such other activities which are reasonably contemplated to be necessary for the commercial success of the Products;

(b) conduct all research pursuant to this Agreement in good scientific manner, and in compliance in all material respects with all requirements of applicable laws, rules and regulations, and all other requirements of any applicable good laboratory or clinical practices to attempt to achieve its objectives efficiently and expeditiously;

(c) within 60 days following the end of each six-month period during the term of this Agreement, furnish BMS with written status reports, in summary form, on all SGI activities under this Agreement during such six-month period;

(d) file for marketing approval following the completion of the development of any Product in all Major Markets in the Territory, in a time-frame consistent with the size and financial resources of SGI; and

(e) allow representatives of BMS, upon reasonable notice and during normal business hours, to visit the facilities where the research is being conducted; provided that such visits shall not be made more than two times per calendar year.

-6-

3.3 Records . SGI shall maintain records, in sufficient detail and in good scientific manner, which shall be complete and accurate and shall fully and properly reflect all work done and results (including, without limitation, the Results) achieved in the performance of its development obligations under this Agreement (including all data in the form required under all applicable laws and regulations).

3.4 Commercialization Responsibilities . Subject to Section 3.5, during the term of this Agreement, following the completion of the development of any Product, SGI and/or its Affiliates or sublicensees shall:

(a) Market and sell such Product under a trademark or trademarks owned or acquired by SGI. SGI shall be solely responsible for all matters relating to such trademark(s), including without limitation the registration, maintenance and prosecution of such trademark(s) in each country in the Territory where such Product is being marketed and sold. SGI shall bear all liability of any kind with respect to such trademark(s) and the use of such trademark(s) by SGI, its Affiliates and its sublicensees.

(b) Promptly provide BMS with a copy of all reasonably material correspondence to or from health authorities in any country in the Territory relating to any material development affecting such Product (including both its approval and labeling), and, within one month of receipt by SGI, its Affiliates or sublicensees, SGI shall provide, or cause its Affiliates or sublicensees to provide, BMS with copies of all approvals and labeling changes received from the health authorities in any country in the Territory.

(c) Initiate a commercial launch and diligently promote the sale of such Product in each Major Market in the Territory as soon as practicable after receiving all governmental approvals (including reimbursement price approval, if any) necessary to market and sell such Product in such country.

3.5 Market Conditions . SGI’s development and commercialization diligence obligations set forth in this Section 3 with respect to any Product shall be required only to the extent that such Product warrants such efforts in light of then prevailing market conditions, including the existence of new or more competitive technologies.

4. GRANT OF LICENSE AND OTHER RIGHTS .

4.1 License Grant .

(a) Subject to the terms and conditions of this Agreement and, with respect to the licenses granted to BMS thereunder, of the respective BMS In-Licenses, BMS hereby grants to SGI a right and license (or, in the case of Patents licensed to BMS under the BMS In-Licenses, a sublicense), under the Licensed Technology, to make, have made, use, offer to sell, sell and have sold Products (except as set forth in Section 4.1(b)) in the relevant Field, as determined under Section 4.1(d), and in the Territory.

(b) Notwithstanding Section 4.1(a):

-7-

(i) The right and sublicense granted in Section 4.1(a) under the Licensed Technology relating to the Enzon Patents shall be to make, have made, use, sell and have sold Enzon Products only;

(ii) The right and sublicense granted in Section 4.1(a) under the Licensed Technology relating to the Ixsys Patents shall be to make, have made, use, sell and have sold Ixsys Products only; and

(iii) The right and sublicense granted in Section 4.1(a) under the Licensed Technology relating to the Washington Patents shall be to make, have made, use, sell and have sold Washington Products only.

(c) With respect to the Licensed Technology, the right and license granted to SGI under Section 4.1(a) shall be either exclusive or partially exclusive or non-exclusive, as set forth in Exhibit A . Except as set forth in this Agreement: (i) BMS shall retain no right to use the Licensed Technology for which SGI is granted a right and license that is exclusive; (ii) BMS shall retain the right to use outside the Field the Licensed Technology for which SGI is granted a right and license that is partially exclusive; and (iii) BMS shall retain all rights to use the Licensed Technology for which SGI is granted a right and license that is non-exclusive. SGI acknowledges that the right and license granted to SGI under this Agreement with respect to Licensed Technology licensed to BMS under the BNS In-Licenses is subject to all of the rights therein retained by the respective licensors thereunder.

(d) Subject to the limitations set forth in Section 4.1(b), the field (the “Field”) with respect to Licensed Technology for which SGI is granted a right and license that is exclusive under Section 4.1(c) shall be the treatment and diagnosis of conditions and diseases in humans and animals. The Field with respect to Licensed Technology for which SGI is granted a right and license that is partially exclusive under Section 4.1(c) shall be: (i) if Exhibit A indicates that such license is partially exclusive for linkers, all monoclonal antibody targeting applications; or (ii) if Exhibit A indicates that such license is partially exclusive for cancer, the treatment and diagnosis of cancer in humans. The Field with respect to Licensed Technology for which SGI is granted a right and license that is non-exclusive under Section 4.1(c) shall be the treatment and diagnosis of cancer in humans. Notwithstanding the foregoing, the Field with respect to the G28-5 Licensed Technology shall be for the use of the antibody G28-5 fused with a toxin for the treatment of cancer in humans.

4.2 Right to Sublicense or Sub-sublicense .

(a) Subject to Sections 4.2(b) and (c), SGI shall have the right to grant sublicenses or sub-sublicenses, without restriction on use, to Third Parties under the license and sublicense granted exclusively to SGI under this Agreement. Subject to Sections 4.2(b) and (c), SGI shall have the right to grant sublicenses or sub-sublicenses, solely for purposes of sponsoring research consistent with SGI’s development obligations under Section 3 or for purposes of manufacturing, marketing or selling Products the development of which was commenced by SGI during the term of this Agreement, to Third Parties under the license and sublicense granted partially exclusively or non-exclusively to SGI under this Agreement. In the event of any such

-8-

sublicensing or sub-sublicensing, SGI shall submit to BMS all material terms of any proposed sublicense or sub-sublicense for approval by BMS, which submission BMS shall consider in good faith and which approval BMS shall not unreasonably withhold. BMS shall provide to SGI its approval, or the basis for withholding approval, of such sublicense or sub-sublicense within 20 days after submission by SGI of a proposed term sheet containing all of the material terms of the proposed sublicense or sub-sublicense. The only basis upon which BMS may reasonably withhold its approval of a proposed sublicense or sub-sublicense shall be its reasonable determination that the proposed sublicensee or sub-licensee does not have the resources or experience necessary to fulfill its obligations under the proposed sublicense or sub-sublicense. BMS may not reasonably withhold its approval based on competitive concerns. The parties acknowledge and agree that SGI currently intends to sublicense certain of the Licensed Technology to CellPro, Inc., in accordance with this Section 4.2. To the extent that the Licensed Technology to be sublicensed to CellPro includes Licensed Technology licensed to BMS under the BMS In-License Agreements, is sublicensed subject to any limitations or restrictions under such BMS In-License Agreements and is to be sublicensed solely in connection with Products and potential Products having only ex vivo application, BMS hereby consents to such sublicensing.

(b) SGI shall be primarily responsible for all payments due and the making of reports under this Agreement by its sublicensees and shall guarantee their compliance with all applicable terms of this Agreement. Each prospective sublicensee or sub-sublicensee shall agree in writing (i) (A) to maintain insurance coverage at the same levels and on the same terms and conditions as set forth in Section 11.5, which insurance shall name BMS as an additional insured, or (B) to maintain a self-insurance plan that substantially complies with the requirements of Section 11.5, provided that BMS reasonably determines in advance in writing that such sublicensee’s or sub-sublicensee’s self-insured plan is adequate given its financial condition, and, at EMS’s request (but not more than annually), such sublicensee or sub-sublicensee provides written evidence of such self-insurance; and (ii) to keep books and records and permit BMS to review such books and records pursuant to Sections 7.3, 7.4 and 7.5 and to observe all other applicable terms of this Agreement.

(c) In the event of a breach by a sublicensee of SGI in the observance of applicable terms of this Agreement, BMS shall be entitled to proceed, at BMS’s sole discretion, against such sublicensee and/or SGI to enforce this Agreement. In furtherance of the foregoing and BMS’s rights thereunder, each sublicense granted by SGI pursuant to this Section 4.2 shall explicitly provide that BMS is a third party beneficiary of such sublicense.

4.3 Reservation of Rights by BMS . SGI acknowledges and agrees that, notwithstanding the right and license granted to SGI under this Agreement, BMS retains the right to use the Licensed Technology for internal research purposes and in connection with any research collaboration with a Third Party(ies) commenced prior to the Effective Date; provided, however, that BMS may sublicense the Licensed Technology relating to one or more of the Patents set forth in Table 5 of Exhibit A to Third Parties only for purposes of developing, manufacturing, marketing or selling products the development of which was commenced by BMS.

-9-

5. INITIAL PAYMENT; ROYALTIES .

5.1 Initial Payment . In partial consideration of the right and license granted by BMS to SGI under this Agreement, SGI shall pay BMS a license fee of $500,000 within 10 days after the date of this Agreement (the date on which such payment is made, the “Effective Date”). Notwithstanding any other provision of this Agreement, such fee shall be non-refundable and non-creditable against any other payments to be made by SGI under this Agreement.

5.2 Royalties . In further consideration of the right and license granted by BMS to SGI under this Agreement, subject to Sections 5.3, 5.4 and 9.1(b), during the Royalty Term, SGI shall pay to BMS a royalty on Net Sales of Products commencing on the First Commercial Sale of any Product by SGI, its Affiliates or its sublicensees in any country in the Territory, as follows:

(a) With respect to Products covered by Licensed Technology relating to one or more of the Patents set forth in Table 1 of Exhibit A (such Licensed Technology, the “BR96 sFv-PE4O Program”), at the rate of 4%.

(b) With respect to Products covered by Licensed Technology relating to one or more of the Patents set forth in Table 2 of Exhibit A (such Licensed Technology, the “BR96/Drug Conjugate Program”), at the rate of 6% on annual Net Sales up to and including $200,000,000, and 8% on annual Net Sales in excess of $200,000,000; provided that such thresholds shall be reduced pro rata with respect to any partial year for which royalties under this Section 5.2(b) are to be calculated.

(c) With respect to Products covered by Licensed Technology relating to one or more of the Patents set forth in Table 3 of Exhibit A (such Licensed Technology, the “G28-5 sFv/Immunotoxin Program”), at the rate of 3%.

(d) With respect to Products covered by Licensed Technology relating to one or more of the Patents set forth in Table 4 of Exhibit A (such Licensed Technology, the “BDl Program”), at the rate of 2%.

(e) With respect to Products covered by Licensed Technology relating to one or more of the Patents set forth in Table 5 of Exhibit A (such Licensed Technology, the “Adept Program”), at the rate of 2%.

(f) With respect to Residual Products covered by Licensed Technology relating to one or more of the Patents or the antibodies set forth in Table 6 of Exhibit A (such Licensed Technology, the “Residual Program”) (each of the BR96 sFv-PE4O Program, BR96/Drug Conjugate Program, G28-5 sFv/Immunotoxin Program, BD1 Program, Adept Program and the Residual Program, a “Research Program”), at the rate of 1%.

(g) With respect to Products covered by Licensed Technology relating solely to one or more of Patents 5,491,088, 5,204,244, 5,202,238, 5,482,856 and 333,840 (Application), 459,354 (Application), 08/285,936 (Application) and 08/487,860 (Application) and not covered by any of the other Licensed Technology comprising any Research Program, at the rate of 3%.

-10-

(h) Notwithstanding the royalty rates set forth in Sections 5.2(a)-(g), with respect to Products having an ex vivo application that are covered by Licensed Technology, at the rate of 1%.

5.3 Third Party Royalties .

(a) SGI, at its sole expense, shall pay all royalties accruing to any Third Party after the Effective Date that result from SGI’s or its Affiliates’ or sublicensees’ activities and that SGI determines, in its reasonable business judgment, are necessary in order to exercise SGI’s rights hereunder to make, have made, use, sell or have sold any Product (all such royalties, “Third Party Royalties”).

(b) SGI shall be entitled to a credit against royalties payable to BMS under this Agreement as follows:

(i) If the aggregate Third Party Royalties and royalties under Section 5.2(a) payable to BMS by SGI with respect to Net Sales of Products covered by the BR96-sFv-PE4O Program during a calendar quarter exceed an amount equal to 10% of such Net Sales, then SGI shall be entitled to a credit against royalties payable to BMS under Section 5.2(a) with respect to such Net Sales in an amount equal to 33% of such excess, but in no event shall the royalties due under Section 5.2(a) be reduced to less than 3% of such Net Sales.

(ii) If the aggregate Third Party Royalties and royalties under Section 5.2(b) payable to BMS by SGI with respect to Net Sales of Products covered by the BR96/Drug Conjugate Program during a calendar quarter exceed an amount equal to 8% of such Net Sales, then SGI shall be entitled to a credit against royalties payable to BMS under Section 5.2(b) with respect to such Net Sales in an amount equal to 33% of such excess, but in no event shall the royalties due under Section 5.2(b) be reduced to less than 5% of such Net Sales.

(iii) If the aggregate Third Party Royalties and royalties under Section 5.2(c) payable to BMS by SGI with respect to Net Sales of Products covered by the G28-5 sFv/Immunotoxin Program during a calendar quarter exceed an amount equal to 10% of such Net Sales, then SGI shall be entitled to a credit against royalties payable to BMS under Section 5.2(c) with respect to such Net Sales in an amount equal to 33% of such excess, but in no event shall the royalties due under Section 5.2(c) be reduced to less than 2% of such Net Sales.

5.4 Reduction for Generic Competition . With respect to any country in the Territory where a Product is a Generic Product, the royalties payable to BMS under Section 5.2 with respect to Net Sales of such Product in such country shall be reduced by 50%, commencing with the calendar quarter during which such Product first becomes a Generic Product in such country. Such reduction shall be in lieu of any other reduction with respect to such royalties under this Agreement to which SGI otherwise would be entitled.

5.5 Obligation to Pay Royalties . In the event that more than one royalty rate under Section 5.2 applies with respect to the Net Sales of any Product, SGI shall pay royalties with respect to such Net Sales at the highest applicable rate. There shall be no obligation to pay

-11-

royalties to BMS under this Section 5 on sales of Products among SGI, its Affiliates and its sublicensees, but in such instances the obligation to pay royalties shall arise upon the sale by SGI, its Affiliates or its sublicensees to unrelated Third Parties.

6. BMS IN-LICENSE EXPENSES .

6.1 Generally . In further consideration of the right and license granted to SGI under this Agreement, SGI shall be solely responsible for the payment of all costs, fees, milestone payments, royalties and other expenses (collectively, “BMS In-License Expenses”) that accrue and become payable by BMS under the several BMS In-Licenses, as may be amended or renegotiated from time to time, on or after the Effective Date, and for the making of all required reports associated with any such payments. All royalties paid by SGI with respect to Net Sales of a Product that is covered by the BR96-sFv-PE4O Program, the BR96/Drug Conjugate Program or the G28-5 sFv/Immunotoxin Program that constitute BMS In-License Expenses shall be deemed to be Third Party Royalties with respect to Net Sales of such Product for purposes of Section 5.3. SGI acknowledges that it has received a complete and correct copy of all of the BMS In-Licenses.

6.2 Notices of Payment .

(a) Within 20 days after SGI pays any BMS In-License Expense other than royalties, SGI shall provide notice of such payment to BMS. Each such notice shall set forth the amount of such payment and the reason such payment was made.

(b) In conjunction with each royalty statement provided by SGI under Section 7.1, SGI shall provide a statement of all royalties paid by SGI as BMS In-License Expense since the date of the last previous such statement provided by SGI. Each such report shall set forth the calculation of the royalties paid by SGI as BMS In-License Expenses during the relevant period.

6.3 Payments Non-Creditable . Except as expressly set forth in Section 5.3(b), SGI’s payment of BMS In-License Expenses shall not be creditable against any other payments to be paid by SGI under this Agreement.

7. PAYMENTS AND REPORTS .

7.1 Payment . All royalty payments payable to BMS under this Agreement shall be paid quarterly within 60 days of the end of each calendar quarter. Each such payment shall be accompanied by a statement, Product-by-Product and country-by-country of the amount of Net Sales during such quarter and the amount of royalties due on such Net Sales.

7.2 Mode of Payment . SGI shall make all payments required under this Agreement as directed by BMS from time to time in U.S. Dollars. Whenever for the purpose of calculating royalties, conversion from any foreign currency shall be required, such conversion shall be at the rate of exchange published in The Wall Street Journal, Eastern U.S. edition, for the last business day of the calendar quarter in which such sales were made.

-12-

7.3 Records Retention . SGI, its Affiliates and its sublicensees shall keep complete and accurate records (specifically including originals or copies of documents supporting entries in the books of account) pertaining to the sale of Products in the Territory and covering all transactions from which Net Sales are derived for a period of three calendar years after the year in which such sales occurred or such longer period as may be required under the respective BMS In-Licenses, and in sufficient detail to permit BMS to confirm the accuracy of royalty calculations hereunder.

7.4 Audit Request . At the request of BMS, SGI, its Affiliates and its sublicensees shall permit an independent certified public accountant appointed by BMS, at reasonable times and upon reasonable notice (but in no event more than once per calendar year), to examine those records and all other material documents relating to or relevant to Net Sales in the possession or control of SGI, its Affiliates or its sublicensees, for a period of three years after such royalties have accrued, as may be necessary to: (i) determine the correctness of any report or payment made under this Agreement; or (ii) obtain information as to the royalties payable for any calendar quarter in the case of SGI’s failure to report or pay pursuant to this Agreement. Said accountant shall not disclose to BMS any information other than information relating to said reports, royalties, and payments. The results of any such examination shall be made available to both Parties. BMS shall bear the full cost of the performance of any such audit except as hereinafter set forth. If, as a result of any inspection of the books and records of SGI or its Affiliates or its sublicensees, it is shown that SGI’s royalty payments under this Agreement were less than the amount which should have been paid, then SGI shall make all payments required to be made to eliminate any discrepancy revealed by said inspection within 15 days after BMS’s demand therefor. Furthermore, if the royalty payments made by SG1 were less than 95% of the amount of royalty payments which should have been paid with respect to the period in question, SGI shall also reimburse BMS for the cost of such examination.

7.5 Taxes . All payments due under this Agreement shall be paid in full without deduction except for withholding taxes, if any, required by law in any country in the Territory with respect to such payment. In the event that SGI is required to withhold any tax to the revenue authorities in any country in the Territory regarding any payment to BMS due to the laws of such country, such amount shall be deducted by SGI, and it shall notify BMS and promptly furnish BMS with copies of any tax certificate or other documentation evidencing such withholding.

7.6 Interest on Late Payments . SGI shall pay interest on any payment to BMS under this Agreement that is not made by the date due hereunder at a rate equal to the prime rate plus 2%, compounded monthly, obtained from The Wall Street Journal, Eastern U.S. edition, on the business day next preceding the date such payment was due, from such date until payment in full has been made.

7.7 Obligations Under Ixsys Agreement . Notwithstanding any other provision of this Agreement, with respect to Ixsys Products, SGI shall make reports to Ixsys, keep and maintain records of Net Sales and grant access to such records by an independent accountant to the same extent required of BMS under the Ixsys Agreement.

-13-

8. REPRESENTATIONS AND WARRANTIES .

8.1 Representations and Warranties of Both Parties . Each Party represents and warrants to the other Party that: (i) it is free to enter into this Agreement; (ii) in so doing, it will not violate any other agreement to which it is a party; and (iii) it has taken all corporate action necessary to authorize the execution and delivery of this Agreement and the performance of its obligations under this Agreement.

8.2 Representation and Warranty of BMS . BMS represents and warrants to SGI that: (i) BMS has obtained all consents necessary to grant the right and license granted to SGI under this Agreement, including without limitation all consents required under the respective BMS In-Licenses; (ii) all payments and obligations that accrue under the BMS In-Licenses prior to the Effective Date have been paid, fulfilled or otherwise discharged, or will be paid, fulfilled or discharged when due; (iii) neither party to the respective BMS In-Licenses has given the other party notice that such other party is in breach under such BMS In-License; and (iv) BMS has provided to SGI a complete copy of the BMS In-License Agreements.

8.3 BMS Disclaimer of All Representations and Warranties . EXCEPT AS SET FORTH IN SECTIONS 8.1 AND 8.2, BMS DOES NOT MAKE ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO WARRANTIES OF QUALITY, PERFORMANCE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT, WITH RESPECT TO THE LICENSED TECHNOLOGY, THE PRODUCTS OR ANY MATERIALS TRANSFERRED TO SGI UNDER THIS AGREEMENT. SGI acknowledges and agrees that BMS is licensing the Licensed Technology to SGI strictly on an “AS IS, WHERE IS” basis and that SGI shall have no claims or causes of action of any kind against BMS with respect thereto.

9. PATENTS; IMPROVEMENTS .

9.1 Patent Filing, Maintenance and Prosecution .

(a) Subject to Section 9.3, with respect to Patents that are licensed to SGI exclusively under this Agreement and with respect to Improvements relating to or arising from such Patents, SGI shall have the first right, in its sole discretion and at its sole cost and expense, to determine the strategies for prosecuting such Patents and to determine whether to maintain such Patents in each country in the Territory. With respect to Patents that are licensed to SGI partially exclusively or non-exclusively under this Agreement and with respect to Improvements relating to or arising front such Patents, BMS shall have the first right, in its sole discretion and at its sole cost and expense, to determine the strategies for prosecuting such Patents and to determine whether to maintain such Patents in each country in the Territory.

(b) In the event that the Party having the first right to prosecute and maintain a Patent under Section 9.1(a) elects to abandon the prosecution or maintenance of any such Patents in any country in the Territory, such Party shall give the other Party notice thereof at least 60 days prior to the date on which such other Party is required by law to make a filing in order to preserve rights to patent protection in such country, and the other Party shall have the right to do so, at its

-14-

own expense, in the name of the owning or controlling Party. In the event that BMS elects to abandon the prosecution or maintenance in any country in the Territory of any Patent licensed to SGI partially exclusively or non-exclusively under this Agreement and SGI elects to assume such prosecution or maintenance, then SGI shall be entitled to a credit against royalties payable to BMS pursuant to Section 5.2 with respect to Net Sales of any Product covered by such Patent equal to the amount of the actual costs and expenses (including reasonable attorneys’ fees) incurred by SGI in connection with such prosecution or maintenance. In the event that SGI elects to abandon the prosecution or maintenance in any country in the Territory of any Patent licensed to SGI exclusively under this Agreement and BMS elects to assume such prosecution or maintenance, then SGI’s right and license under this Agreement in such country with respect to the Licensed Technology relating to such Patent shall terminate.

9.2 Information; Consultation; Cooperation .

(a) With respect to the filing, prosecution and maintenance of any Patent pursuant to Section 9.1(a), the filing Party shall keep the other Party informed of its decisions and actions in this regard by providing a report thereof to such other Party. Further, in connection with any such filing, prosecution or maintenance by either Party, such Party shall consult with the other Party and in good faith consider and give due respect to such other Party’s position with respect thereto. In the event that the sole owning or controlling Party elects not to file for patent protection or prosecute or maintain such Patents and the other Party elects to do so, such owning or controlling Party shall cooperate with the other Party in such filing, prosecution or maintenance.

(b) In addition, with respect to the filing, prosecution and maintenance of any Patent pursuant to Section 9.1(a) that covers an Improvement by a Party that does not solely own such Improvement, the filing Party shall cooperate with the other Party in determining strategies for such filing, prosecution and maintenance, and the filing Party shall make its patent counsel available for consultation with patent counsel for the other Party for this purpose.

9.3 Prior Patent Rights . Notwithstanding anything to the contrary in this Agreement, with respect to any Patents that have been licensed to BMS under the BMS In-Licenses, the rights and obligations of the Parties under Sections 9.1 and 9.2 with respect thereto shall be subject to BMS’s licensors’ rights to participate in prosecution and maintenance thereof, in accordance with the terms and conditions of the relevant BMS In-Licenses.

9.4 Improvements .

(a) Improvements that are made by an employee or agent of SGI, solely or jointly other than with an employee or agent of BMS, shall be owned by SGI. Improvements that are made jointly by employees or agents of SGI and BMS shall be jointly owned by SGI and BMS and treated as joint inventions under U.S. laws applicable to joint inventions. Improvements that are made by an employee or agent of BMS, solely or jointly other than with an employee or agent of SGI, shall be owned by BMS. Except as otherwise set forth in this Agreement, each of BMS and SGI shall retain its unrestricted rights to make, have made, use, sell and have sold all Improvements that are owned by it either solely or jointly with the other Party.

-15-

(b) In the event that, during the term of this Agreement, either Party (the “proprietor Party”) develops or acquires the rights to (including the right to license or sublicense) any Improvements to Licensed Technology that is licensed to SGI under this Agreement partially exclusively or non-exclusively, the proprietor Party shall promptly disclose full and complete information relating to such Improvements to the other Party (the “non-proprietor Party”).

(c) With respect to any such Improvements, the proprietor Party shall grant to the non-proprietor Party a royalty-free, non-exclusive right and license, including the right to grant sublicenses thereof, to use such Improvements during the term of this Agreement: (i) with respect to such right and license granted to SGI by BMS, solely for the manufacture, use or sale of the Products pursuant to the right and license granted to SGI under this Agreement, and (ii) with respect to such right and license granted to BMS by SGI, (A) if such Improvement is to Licensed Technology that is licensed to SGI under this Agreement partially exclusively for cancer, for any purpose that does not relate to human cancer; (B) if such Improvement is to Licensed Technology that is licensed to SGI under this Agreement partially exclusively for linkers, for any purpose that does not relate to monoclonal antibody targeting applications; and (C) if such Improvement is to Licensed Technology that is licensed to SGI under this Agreement non-exclusively, for any purpose. Notwithstanding the foregoing, the non-proprietor party shall not be entitled to use any Improvement relating to or arising from the Adept Program to develop, make, use or sell any product (including any Product) having the same primary mode of action as any product (including any Product) being developed, marketed or sold by the proprietor party.

9.5 Prior Improvement Rights; Reporting . Notwithstanding anything to the contrary in this Agreement, SGI’s rights in and to any Improvements relating to or arising from any Patents that have been licensed to BMS under the BMS In-Licenses shall be subject to BMS’s licensors’ rights therein under the respective BMS In-Licenses. Each Party shall be responsible for making all reports to such licensors concerning its respective Improvements.

10. PATENT ENFORCEMENT: INFRINGEMENT .

10.1 Patent Enforcement . As soon as it shall have knowledge thereof, each Party shall promptly advise the other Party of any infringement of the Patents in the Territory by a Third Party. With respect to any Patent that is licensed to SGI exclusively under this Agreement, SGI shall have the first right, but not the duty, to institute infringement actions against Third Parties. With respect to any Patent that is licensed to SGI partially exclusively or non-exclusively under this Agreement, BMS shall have the first right, but not the duty, to institute infringement actions against Third Parties; provided, however, that SGI shall have the right, at its sole discretion, to participate therein at its own expense. For so long as SGI shall continue to participate materially in any such action, BMS shall consult with SGI and take into account each Party’s relative interests in such Patent and such infringement action before entering into any settlement arrangement or other amicable arrangement with respect thereto. If the Party having the first right to institute an infringement proceeding against an offending Third Party does not do so within 90 days after receipt of notice from the other Party, such other Party shall have the right, but not the duty, to institute such an action. The costs and expenses of any such action (including reasonable fees of attorneys and other professionals) shall be borne by the Party instituting the action, or, if the Parties elect to cooperate in instituting and maintaining such action, such costs and expenses

-16-

shall be borne by the Parties in such proportions as they may agree in writing. Each Party shall execute all necessary and proper documents and take such actions as shall be appropriate to allow the other Party to institute and prosecute such infringement actions. Any award paid by Third Parties as a result of such an infringement action (whether by way of settlement or otherwise) shall be paid to the Party who instituted and maintained such action, or, if both parties instituted and maintained such action, such award shall be allocated among the Parties in proportion to their respective contributions to the costs and expenses incurred in such action.

10.2 Infringement Action by Third Parties . As soon as it shall have knowledge thereof, each Party shall promptly advise the other Party of any infringement action instituted by a Third Party with respect to any Product or of any grounds for any such action, regardless of whether such action has been instituted. In the event of the institution of any suit by a Third Party against SGI for patent infringement involving the manufacture, sale, distribution or marketing of any Product in the Territory, SGI shall have the right to defend such suit at its own expense, and BMS hereby agrees to assist and cooperate with SGI, at its own expense, to the extent necessary in the defense of such suit; provided, however, that with respect to any suit involving Patents licensed to BMS under the BMS In-Licenses, BMS shall have the right, at its sole discretion, to participate therein at its own expense. For so long as BMS shall continue to participate materially in any such action, SGI shall not enter into any settlement arrangement or other amicable arrangement without the prior written consent of BMS. During the pendency of such action, SGI shall continue to make all payments due under this Agreement. If, as a result of any judgment, award, decree or settlement resulting from an action instituted by a Third Party, SGI is required to pay damages and/or a royalty to such Third Party, SGI shall be solely responsible for the payment of such damages and/or such royalties for such Products to such Third Party and shall continue to pay royalties pursuant to this Agreement in the country which is the subject of such action. All royalties paid by SGI pursuant to this Section 10.2 shall be deemed to constitute Third Party Royalties for purposes of Section 5.3.

10.3 Prior Rights . Notwithstanding anything to the contrary in this Agreement, with respect to any Patents that have been licensed to BMS under the BMS In-Licenses, the rights and obligations of the Parties under this Section 10 with respect thereto shall be subject to BMS’s licensors’ rights to enforce and defend against infringement claims with respect to same and all other applicable provisions of the respective BMS In-Licenses.

11. INDEMNIFICATION .

11.1 By SGI . SGI, including any successor to SGI, shall, and shall obligate its Affiliates or its sublicensees, if any, to, indemnify and hold BMS and its Affiliates, and their respective directors, officers, employees and agents harmless from and against any and all liability, damage to or loss of property or injury to or death of any person or persons, costs and expenses (including reasonable attorney’s fees) resulting from claims arising out of:

(a) negligence, recklessness or wrongful intentional acts or omissions of SGI, its Affiliates or its sublicensees, if any, and their respective directors, officers, employees and agents, in connection with the use or development of any Licensed Technology; or

-17-

(b) any warranty claims, Product recalls or any tort claims of personal injury (including death) or property damage relating to or arising out of the manufacture, use, distribution or sale of any Product or services by SGI, its Affiliates or its sublicensees, if any, due to any negligence, recklessness or wrongful intentional acts or omissions by, or strict liability of, SGI, its Affiliates or its sublicensees, if any, and their respective directors, officers, employees and agents.

11.2 By BMS . In the event that BMS makes, has made, uses, sells or has sold any Product pursuant to Section 13.6(c) or (d), BMS shall, and shall obligate its sublicensees, if any, to, indemnify SGI and its Affiliates, and their respective directors, officers, employees and agents with respect thereto to the same extent as the indemnification required to be provided by SGI in Section 11.1.

11.3 Notice . In the event that either Party is seeking indemnification under Section 11.1 or Section 11.2, such Party shall inform the indemnifying Party of a claim as soon as reasonably practicable after it receives notice of the claim, shall permit the indemnifying Party to assume direction and control of the defense of the claim (including the sole right to settle it at the sole discretion of the indemnifying Party, provided that such settlement does not impose any obligation on the indemnified Party), and shall cooperate as requested (at the expense of the indemnifying Party) in the defense of the claim.

11.4 Complete Indemnification . As the Parties intend complete indemnification, all costs and expenses of enforcing this Section 11 shall also be reimbursed by the indemnifying Party.

11.5 Insurance .

(a) In furtherance and not in limitation of any indemnity obligations of SGI under this Agreement: (i) commencing on the Effective Date and thereafter for the period of time required hereinbelow, SGI shall obtain and maintain on an on-going basis comprehensive general liability insurance in the amount of $1,000,000 per occurrence and $2,000,000 annual aggregate combined single limit for bodily injury and property damage liability; and (ii) commencing not later than 30 days prior to the first use in humans of the first potential Product and thereafter for the period of time required hereinbelow, SGI shall obtain and maintain on an on-going basis products liability insurance (including contractual liability coverage on SGI’s indemnification obligations under this Agreement) in the amount of at least $25,000,000 per occurrence and annual aggregate combined single limit for bodily injury and property damage liability. All of such insurance coverage shall be maintained with a insurance company or companies having an A. M. Best rating of “A-” or better and an aggregate deductible not to exceed $100,000 per occurrence.

(b) Not later than the Effective Date with respect to the comprehensive general liability coverage, and not later than 30 days prior to the first use in, humans of the first potential Product with respect to the products liability coverage, SGI shall provide to BMS a certificate(s) evidencing all such required coverage hereunder. Thereafter SGI shall maintain such insurance coverage without interruption during the term of this Agreement and for a period

-18-

of at least 10 years after the expiration or termination of the term and shall provide certificates evidencing such insurance coverage without interruption on an annual basis (by no later than the annual renewal date for such coverage) during the period of time for which such coverage must be maintained.

(c) SGI’s insurance shall name BMS as an additional insured, shall state that such insurance is primary to any valid and collectible insurance available to BMS that also insures the same loss for which SGI has liability pursuant to this Agreement (including, without limitation, under the indemnification provisions hereof), shall contain a cross-liability or severability of interest clause, and shall state that BMS shall be provided at least 60 days’ prior written notice of any cancellation or material change in the insurance policy. SGI shall promptly provide BMS with a copy of all communications passing between SGI and the carrier(s) providing the coverage required under this Section 11.5. SGI’s failure to comply with the provisions of this Section 11.5 shall be deeded to be a material breach of this Agreement.

12. PUBLICATION; CONFIDENTIALITY .

12.1 Notification . Both Parties recognize that the Parties may wish to publish the results of its development efforts relating to the Products. However, both Parties also recognize the importance of acquiring patent protection on inventions. Consequently, any proposed publication by either Party on the subject matter of any of the Licensed Technology that is licensed to SGI hereunder partially exclusively or non—exclusively, or any subject matter related thereto, shall comply with this Section 12. At least 30 days before a manuscript is to be submitted to a publisher, the publishing Party will provide the other Party with a copy of the manuscript. If the publishing Party wishes to make an oral presentation, it will provide the other Party with a copy of the abstract (if one is submitted) at least 30 days before it is to be submitted. The publishing Party will also provide to the other Party a copy of the text of the presentation, including all slides, posters and any other visual aids, at least 30 days before the presentation is made.

12.2 Review of Proposed Publications . The receiving Party will review the manuscript, abstract, text or any other material provided under Section 12.1 for the express purpose of determining whether patentable subject matter or Confidential Information (as such term is defined herein) is disclosed. The other Party will notify the publishing Party within 30 days of receipt of the proposed publication if the other Party, in good faith, determines that patentable subject matter is or may be disclosed, or if the other Party, in good faith, believes Confidential Information or proprietary information is or may be disclosed. If it is determined by the other Party that patent applications should be filed, the publishing Party shall delay its publication or presentation for a period not to exceed 90 days from the other Party’s receipt of the proposed publication to allow time for the filing of patent applications covering patentable subject matter. In the event that the delay needed to complete the filing of any necessary patent application will exceed the 90-day period, the Parties will discuss the need for obtaining an extension of the publication delay beyond the 90-day period. If it is determined in good faith by the other Party that Confidential Information or proprietary information is being disclosed, the Parties will consult in good faith to arrive at an agreement on mutually acceptable modifications to the proposed publication to avoid such disclosure. The publishing Party of any manuscript, text or

-19-

oral presentation will acknowledge the other Party for its contribution to the material being published or presented. In addition, to the foregoing, SGI shall cooperate with BMS to allow BMS to fulfill any obligations it may have under the respective BMS In-Licenses on account of any proposed publication by SGI.

12.3 Confidentiality; Exceptions . Except to the extent expressly authorized by or required for the performance of this Agreement or otherwise agreed in writing, the Parties agree that, for the term of this Agreement and for five years thereafter (or any longer term provided for in any BMS In-License) the receiving Party, its Affiliates and its sublicensees (collectively, the “receiving Party”) shall keep, and shall ensure that its officers and directors keep, completely confidential and shall not publish or otherwise disclose and shall not use for any purpose inconsistent with this Agreement any information furnished to it by the disclosing Party, its Affiliates or its sublicensees that is marked as confidential or, if furnished orally, that the disclosing Party notifies the receiving Party is confidential within 10 days after such information is furnished, or any information developed pursuant to this Agreement (collectively, “Confidential Information”). This Section 12.3 shall not apply to information that the receiving Party can establish: (i) is or hereafter becomes generally available to the public other than by reason of any default with respect to a confidentiality obligation; (ii) was already known to the receiving Party when disclosed by the disclosing Party, as evidenced by prior written records; or (iii) is disclosed to the receiving Party by a Third Party who reasonably was not known by the receiving Party to be in default of any confidentiality obligation to the disclosing Party.

12.4 Exceptions .

(a) The restrictions contained in Section 12.3 shall not apply to Confidential Information that (i) is submitted by the receiving Party to governmental authorities to facilitate the issuance of marketing approvals for a Product, provided that reasonable measures shall be taken to assure confidential treatment of such information; (ii) is provided by the receiving Party to Third Parties under appropriate terms and conditions, including confidentiality provisions equivalent to those in this Agreement, for consulting, manufacturing development, manufacturing, external testing and marketing trials; or (iii) is otherwise required to be disclosed in compliance with applicable laws or regulations or order by a court or other regulatory body having competent jurisdiction; provided that if a receiving Party is required to make any such disclosure of the other Party’s Confidential Information it will, except where impracticable for necessary disclosures, for example to physicians conducting studies or to health authorities, give reasonable advance notice to the other Party of such disclosure requirement and, except to the extent inappropriate in the case of patent applications, will use its best efforts to secure confidential treatment of such Confidential Information required to be disclosed.

(b) Nothing in Section 12.3 shall prevent SGI: (i) in connection with efforts to secure financing at any time during the term of this Agreement, from issuing statements and sharing information as to SGI’s agreements with BMS, achievements made, and the status of the work being done, under this Agreement, so long as such statements or information do not jeopardize the ability to obtain patent protection on Improvements or disclose technical or scientific Confidential Information; or (ii) from issuing statements that SGI determines to be necessary to comply with applicable law (including the disclosure requirements of the U.S.

-20-

Securities and Exchange Commission, Nasdaq or any other stock exchange on which securities issued by SGI are traded); provided that, in the case of statements made to or information shared with the general public, to the extent practicable under the circumstances, SGI shall provide BMS with a copy of the proposed text of such statements sufficiently in advance of the scheduled release thereof to afford BMS a reasonable opportunity to review and comment upon the proposed text.

12.5 Limitations on Use . Each Party shall use, and cause each of its Affiliates and its sublicensees to use, any Confidential Information obtained by it from the other Party, its Affiliates or its sublicensees, pursuant to this Agreement or otherwise, solely in connection with the activities or the transactions contemplated hereby.

12.6 Remedies . Each Party shall be entitled, in addition to any other right or remedy it may have, at law or in equity, to an injunction, without the posting of any bond or other security, enjoining or restraining the other Party, its Affiliates and/or its sublicensees from any violation or threatened violation of this Section 12.

13. TERM; TERMINATION .

13.1 Term . The term of this Agreement shall commence as of the Effective Date and, unless sooner terminated as provided hereunder, shall terminate as follows:

(a) As to each Product in each country in the Territory, this Agreement shall terminate upon the expiration of the Royalty Term.

(b) This Agreement shall terminate in its entirety upon its termination in all countries in the Territory.

13.2 Termination by BMS . BMS shall have the right to terminate this Agreement in the event that on or before the 18-month anniversary of the Effective Date SGI shall not have both:

(i) Obtained and received unconditional cash payment of an aggregate of at least $4,000,000 in working’ capital; and

(ii) Completed each of the following to the reasonable satisfaction of BMS, to the extent that the scientific results obtained by SGI and prevailing market conditions do not, in the reasonable determination of BMS, indicate that same should be abandoned:

(A) Evaluation of assays to evaluate clinical grade BR96 sFv-PE4O for use in the re-commencement of Phase I studies thereof;

(B) Production and in vitro analysis of anti-CD4O-immunotoxins as anti-cancer agents for purposes of treating hematologic malignancy;

(C) Design of studies to evaluate novel BR96-based drugs; and

-21-

(D) Design of studies to evaluate the utilization of human enzymes in mAb-sFv-enzyme fusion proteins.

13.3 Termination by SGI .

(a) SGI shall have the right to terminate this Agreement in its entirety at any time by giving written notice thereof to BMS, which shall be effective three months from the date such notice is given.

(b) SGI shall have the right to terminate this Agreement partially by terminating a specific Research Program due to reasonable scientific considerations, including without limitation toxicity, inefficacy and lack of bioavailability, by giving written notice thereof to BMS, which shall be effective three months from the date such notice is given.

13.4 Breach . Failure by either Party to comply with any of the material obligations contained in this Agreement (including, without limitation, SGI’s obligation to pay BMS In-License Expenses under Section 6) shall entitle the other Party to give to the Party in default notice specifying the nature of the default and requiring it to cure such default. If such default is not cured within 90 days after the receipt of such notice (or, if such default cannot be cured within such 90-day period, if the Party in default does not commence and diligently continue actions to cure such default), the notifying Party shall be entitled, without prejudice to any of its other rights conferred on it by this Agreement and in addition to any other remedies available to it by law or in equity, to terminate this Agreement by giving written notice to take effect immediately upon delivery of such notice. The right of either Party to terminate this Agreement, as hereinabove provided, shall not be affected in any way by its waiver or failure to take action with respect to any previous default.

13.5 Failure to Maintain Insurance . This Agreement shall terminate automatically and without necessity of any action by either Party in the event that (i) SGI fails to maintain all insurance coverage that it is required to maintain under Section 11.5, or (ii) a sublicensee or sub-sublicensee of SGI fails to maintain all insurance coverage that it is required to maintain under Section 4.2(b) and SGI does not, prior to the cancellation or non-renewal of such coverage, either (A) terminate such sublicense, or (B), obtain the requisite coverage on behalf and for the benefit of such sublicense or sub-sublicensee, unless, in each event, such termination of this Agreement is waived in writing by BMS.

13.6 Effect of Termination .

(a) Following the expiration of SGI’s obligation to pay royalties with respect to any Product in any country in the Territory pursuant to Section 13.1(a), SGI shall have the royalty-free, non-exclusive, perpetual right and license to continue to use the Licensed Technology to make, have made, use, sell and have sold such Product in such country.

(b) Following either the expiration of the term of this Agreement in its entirety pursuant to Section 13.1(b) or the termination of this Agreement by SGI pursuant to Section 13.4, SGI shall have the royalty-free, non-exclusive, perpetual right and license to continue to use

-22-

the Licensed Technology to make, have made, use, sell and have sold the Product in all countries in the Territory, and the license granted to SGI under Section 9.4(c) shall become perpetual. Further, following the expiration of the term of this Agreement in its entirety pursuant to Section 13.1(b), the license granted to BMS under Section 9.4(c) shall become perpetual. Further, following the termination of this Agreement by SGI pursuant to Section 13.4, the license granted to BMS under Section 9.4(c) with respect to Improvements relating to such Licensed Technology shall terminate

(c) Upon the termination of this Agreement by SGI pursuant to Section 13.3(a), by BMS pursuant to Section 13.2 or 13.4, or automatically pursuant to Section 13.5, SGI shall promptly: (i) return to BMS all relevant records, materials or confidential information, including the Results, concerning the Patents, the Know-How and any Products in the possession or control of SGI or any of its Affiliates or sublicensees; and (ii) assign to BMS, or BMS’s designee, its registrations with governmental health authorities, licenses, and approvals of the Products in the Territory, at SGI’s sole expense. Thereafter, SGI shall have no rights whatsoever to use the Licensed Technology for any purpose, and BMS shall have a royalty-free right and license, including the right to grant sublicenses, under the Patents and know-how covering SGI’s Improvements, to make, have made, use, sell and have sold any Products. In such event, BMS shall indemnify SGI as provided in Section 11.2. Further, the license granted to BMS under Section 9.4(c) shall become perpetual, and the license granted to SGI under Section 9.4(c) with respect to Improvements relating to such Licensed Technology shall terminate.

(d) Upon the termination of any Research Program by SGI pursuant to Section 13.3(b), SGI’s right and license and obligations under this Agreement and any applicable BMS In-License with respect to the Licensed Technology associated with such Research Program shall cease, and SGI shall promptly: (1) return to BMS all relevant records, materials or confidential information, including the Results, concerning the Patents, the Know-How and any Products in the possession or control of SGI or any of its Affiliates or sublicensees with respect to such’ Licensed Technology; and (ii) assign to BMS, or BMS’s designee, its registrations with governmental health authorities, licenses, and approvals of any such Products in the Territory, at SGI’s sole expense. Thereafter, SGI shall have no rights or obligations whatsoever relating to such Licensed Technology, and BMS shall have an exclusive (even as to SGI), royalty-free right and license, including ,the right to grant sublicenses, under the Patents, to make, have made, ‘use, sell and have sold any such Products. In such event, BMS shall indemnify SGI as provided in Section 11.2. Further, the license granted to SGI under Section 9.4(c) with respect to Improvements relating to such Licensed Technology shall terminate, and the license granted to BMS under Section 9.4(c) shall become perpetual. All licenses, rights and obligations relating to all Research Programs not identified in SGI’s notice of termination shall remain in full force and effect and shall be unaffected by such notice.

(e) Upon the termination of any BMS In-License, SGI’s right and license and obligations under this Agreement and such BMS In-License with respect to the Licensed Technology licensed to BMS thereunder shall cease, and SGI shall promptly: (i) return to BMS all relevant records, materials or confidential information, including the Results, concerning the Patents, the Know-How and any Products in the possession or control of SGI or any of its Affiliates or sublicensees with respect to such Licensed Technology; and (ii) assign to BMS, or

-23-

BMS’s designee, its registrations with governmental health authorities, licenses, and approvals of any such Products in the Territory. Thereafter, SGI shall have no rights or obligations whatsoever relating to such Licensed Technology. Further, the licenses granted to each Party under Section 9.4(c) with respect to Improvements relating to such Licensed Technology shall terminate.

13.7 Termination of Sublicenses . Upon any termination of this Agreement, all sublicenses and sub—sublicenses granted by SGI under this Agreement shall terminate simultaneously.

13.8 Accrued Rights, Surviving Obligations .

(a) Termination, relinquishment or expiration of this Agreement for any reason shall be without prejudice to any rights which shall have accrued to the benefit of either Party prior to such termination, relinquishment or expiration. Such termination, relinquishment or expiration shall not relieve either Party from obligations which are expressly indicated to survive termination or expiration of this Agreement.

(b) Termination of this Agreement shall not terminate SGI’s obligation to make all payments which have accrued through the date of such termination. All of the Parties’ rights and obligations under Sections 2.4, 7, 8.3, 10, 11, 12.3, 12.4, 12.5, 12.6, 13.6, 15.1, 15.15 and 15.16 shall survive termination.

14. FORCE MAJEURE .

14.1 Events of Force Majeure . Neither Party shall be held liable or responsible to the other Party or be deemed to be in default under or in breach of any provision of this Agreement for failure or delay in fulfilling or performing any obligation of this Agreement when such failure or delay is due to force majeure , and without the fault or negligence of the Party so failing or delaying. For purposes of this Agreement, force majeure shall be defined as causes beyond the control of the Party, including, without limitation, acts of God; acts, regulations, or laws of any government; war; civil commotion; destruction of production facilities or materials by fire, flood, earthquake, explosion or storm; labor disturbances; epidemic; and failure of public utilities or common carriers. In such event SGI or BMS, as the case may be, shall immediately notify the other Party of such inability and of the period for which such inability is expected to continue. The Party giving such notice shall thereupon be excused front such of its obligations under this Agreement as it is thereby disabled from performing for so long as it is so disabled and the 30 days thereafter. However, the Party giving such notice shall use all reasonable efforts to remedy such inability as soon as reasonably possible or seek an alternative arrangement during the period of such inability.

15. MISCELLANEOUS .

15.1 Non-Solicitation . Prior to the First Commercial Sale of the first Product, and for a period of one year thereafter, neither Party shall solicit, induce, encourage or attempt to induce or encourage any employee of the other Party to terminate his or her employment with such other Party or to breach any, other obligation to such other Party.

-24-

15.2 Relationship of Parties . Nothing in this Agreement is intended or shall be deemed to constitute a partnership, agency, employer-employee, or joint venture relationship between the Parties. No Party shall incur any debts or make any commitments for the other, except to the extent, if at all, specifically provided herein.

15.3 Assignment . Neither Party shall be entitled to assign its rights hereunder without the express written consent of the other Party hereto, except that both SGI and BMS may otherwise assign their respective rights and transfer their respective duties hereunder to any assignee of all or substantially all of their respective businesses or in the event of their respective merger or consolidation or similar transaction. No assignment and transfer shall be valid and effective unless and until the assignee/transferee shall agree in writing to be bound by the provisions of this Agreement. Any assignment not in accordance with this Section 15.3 shall be void.

15.4 Binding Effect . 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.

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

15.6 Costs and Expenses . Except as otherwise expressly provided in this Agreement, each Party shall bear all costs and expenses associated with the performance of such Party’s obligations under this Agreement.

15.7 Inconsistency . If there is any inconsistency between the provisions of this Agreement and any other document passing between the Parties, the provisions of this Agreement shall control and be determinative.

15.8 Notice . Any notice, request or other communication required or permitted to be given under or in connection with this Agreement shall be deemed to have been sufficiently given if in writing and personally delivered or sent by registered or certified mail (return receipt requested), facsimile transmission (receipt verified), express courier service (signature required), or telegram, prepaid, to the Party for which such notice is intended, at the address set forth for such Party below:

-25-

or to such other address for such Party as it shall have specified by like notice to the other Party, provided that notices of a change of address shall be effective only upon receipt thereof. If sent by mail, facsimile transmission, express courier service, or telegram, the date of mailing or transmission shall be deemed to be the date on which such notice or request has been given.

15.9 Use of Name . Except as otherwise provided herein, neither Party shall have any right, express or implied, to use in any manner the name or other designation of the other Party or any other trade name or trademark of the other Party for any purpose in connection with the performance of this Agreement.

15.10 Public Announcements . Except as required by law, neither Party shall make any public announcement concerning this Agreement or the subject matter hereof prior to the Effective Date. Thereafter, neither Party shall make any such public announcement without the prior written consent of the other, which shall not be unreasonably withheld. In the event of a, required public announcement, the Party making such announcement shall provide the other Party with a copy of the proposed text prior to such announcement sufficiently in advance of the scheduled release of such announcement to afford such other Party a reasonable opportunity to review and comment upon the proposed text. Following approval of a proposed text, such text may be used in subsequent public announcements without further approval, to the extent it remains accurate, complete and not misleading.

15.11 Waiver . A waiver by either Party of any of the terms and conditions of this Agreement in any instance shall not be deemed or construed to be a waiver of such term or condition for the future, or of any subsequent breach hereof. All rights, remedies, undertakings, obligations and agreements contained in this Agreement shall be cumulative and none of them

-26-

shall be in limitation of any other remedy, right, undertaking, obligation or agreement of either Party.

15.12 Compliance with Law . Nothing in this Agreement shall be deemed to permit a Party to: (i) import, export, reexport, store, sell, distribute or otherwise transfer any Product sold under this Agreement without compliance with applicable laws; or (ii) make any claims with respect to any Product, in promotional materials or otherwise, in any country that is inconsistent with applicable laws.

15.13 Severability . When possible, each provision of this Agreement will be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Agreement is held to be prohibited by or invalid under applicable law, such provision will be ineffective only to the extent of such prohibition or invalidity, without invalidating the remainder of this Agreement. In such event, the Parties agree to substitute a valid and enforceable provision therefor which, as nearly as possible, achieves the desired economic effect and mutual understanding of the Parties under this Agreement.

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

15.15 Governing Law . This Agreement shall be governed by and interpreted in accordance with the laws of the State of New York, without regard to its choice of law principles.

15.16 Arbitration .

(a) Any dispute arising out of or relating to any provisions of this Agreement shall be finally settled by arbitration to be held in San Diego, California, under the auspices and then current commercial arbitration rules of the American Arbitration Association. Such arbitration shall be conducted by three arbitrators appointed according to said rules. The Parties shall instruct such arbitrators to render a determination of any such dispute within 30 days after their appointment. Judgment upon any award rendered may be entered in any court having jurisdiction, or application may be made to such court for a judicial acceptance of the award and an order of enforcement, as the case may be.

(b) Section 15.16(a) shall not prohibit a Party from seeking injunctive relief from a court of competent jurisdiction in the event of a breach or prospective breach of this Agreement by the other Party which would cause irreparable harm to the first Party.

15.17 Entire Agreement . This Agreement sets forth the entire agreement and understanding between the Parties as to the subject matter hereof and merges all prior discussions and negotiations between them, and neither of the Parties shall be bound by any conditions, definitions, warranties, understandings or representations with respect to such subject matter other than as expressly provided herein or as duly set forth on or subsequent to the date hereof in writing and signed by a proper and duly authorized officer or representative of the Party to be bound thereby.

-27-

15.18 Counterparts . This Agreement may be executed simultaneously in any number of counterparts, any one 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.

15.19 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.

* * *

-28-

IN WITNESS WHEREOF, each of the Parties has caused this Agreement to be executed by its duly authorized officer as of the day and year first above written.

In addition, the patents and patent applications (the “Enzon Patents”), together with the know-how related thereto, sublicensed under the Enzon Agreement, are part of, and included in, the BR96 sFV-PE40 Program . [Exclusive]

Table 2 BR96/Drug Conjugate Program

The following patents and patent applications, together with the know-how related thereto, constitute the BR96/Drug Conjugate Program:

A-1

In addition, the patents and patent applications (the “Ixsys Patents”), together with the know-how related thereto, sublicensed under the Ixsys Agreement, are part of, and included in, the BR96/Drug Conjugate Program. [Non-Exclusive]

Table 3 G28-5 SfV/Immunotixin Program

The patents and patent applications (the “Washington Patents”), together with the know-how related thereto, sublicensed under the Washington Agreement constitute the G28-5 sFv/Immunotoxin Program. [Exclusive]

Table 4 BD1 Program

The following patents and patent applications, together with the know-how related thereto, constitute the BD1 Program:

Table 5 ADEPT Program

The following patents and patent applications, together with the know-how related thereto, constitute the ADEPT Program:

A-2

The Residual Program also includes antibodies L6, L49, BR64, BR110, OV578.1 and OV569.1 [Exclusive]

A-3

EXHIBIT B

EXCLUDED AREAS FROM ENZON FIELD

The following areas are specifically excluded from the Enzon Field:

1. Making, having made, using, or selling SCA PROTEIN for Radioimmunoguided Surgery™ (RIGS®), in which a radiolabelled SCA PROTEIN is administered to a cancer patient; time elapses for preferential concentration of the radiolabelled SCA PROTEIN in neoplastic tissue and decrease of background radioactivity in the patient; and such preferentially concentrated radiolabelled SCA PROTEIN is detected within a surgical operative field by a detector probe placed in juxtaposition with tissue suspected of containing said radiolabelled SCA PROTEIN.

2. Making, having made, using, or selling diagnostics based on erbB-2 SCA PROTEINS and therapeutics based on erbB-2 SCA PROTEINS covalently linked to Pseudomonas exotoxin or derivatives or fragments thereof.

3. Making, having made, or selling reagents and kits in the research market for production and cloning of genes encoding SCA PROTEIN(s) and their fusions in a filamentous bacteriophage-derived vector system, and for expression and screening of SCA PROTEINS fused with the minor coat protein or attachment or adsorption protein of filamentous bacteriophage.

4. Selling kits in the research market for cloning, screening, or isolating SCA PROTEINS.

5. Selling products containing SCA PROTEINS in the research market.

6. Selling SCA PROTEIN-containing products to diagnostic companies for inclusion in diagnostic kits.

7. Making, having made, using, or selling catalytic SCA PROTEIN in which a protein binds to and catalyzes the chemical transformation of a substrate and in which an antigen-binding site of an SCA PROTEIN is involved in said catalysis.

8. Making, having made, using, or selling SCA PROTEINS that are, or have been modified by reaction with poly (alkylene glycols).

9. Making, having made, using, or selling SCA PROTEINS fused with, or for the assay or purification of, Tumor Necrosis Factor-alpha (TNF) or Lymphotoxin.

All capitalized terms not otherwise defined in this Exhibit B shall have the meaning assigned thereto, if any, in the Enzon Agreement.

B-1

Exhibit 10.2

July 29, 1999

Bristol-Myers Squibb Company

P.O. Box 4000

Princeton, New Jersey 08543-4000

This letter sets forth the agreement of Bristol-Myers Squibb Company (“ BMS ”) and Seattle Genetics, Inc. (“ SGI ”) to amend that certain License Agreement dated March 30, 1998 between BMS and SGI (the “ Agreement ”) as set forth herein.

For good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties agree as follows:

1. Section 5.2(b) is hereby amended to add the following phrase at the beginning of Section 5.2(b):

“5.2(b) Except as set forth in subsections 5.2(i) and 5.2(j), …”

2. A new Section 5.2(i) relating to use of the peptidic linker technology is added to the Agreement, which shall read in its entirety as follows:

“5.2(i) With respect to Products covered by Licensed Technology relating only to Patent (Application), 062,366, at the rate of 2%.”

3. A new Section 5.2(j) relating to use of BR96 technology is added to the Agreement, which shall read in its entirety as follows:

“5.2(j) With respect to Products covered by Licensed Technology relating to the use of BR96 with any active agent other than doxorubicin, at the rate of 4%.”

4. BMS hereby acknowledges and agrees that SGI has completed, to the satisfaction of BMS, all of the milestones set forth in Section 13.2 of the Agreement.

5. Table 5 of Exhibit A to the Agreement shall be amended to add the following U.S. Patent:

6. All other terms and conditions of the Agreement shall remain unchanged and in full force and effect.

BMS and SGI, intending to be legally bound, have caused this Amendment to be executed by their authorized representatives below.

-2-

Exhibit 10.4

LICENSE AGREEMENT

This License Agreement (this “Agreement”), is entered into as of June 14, 1998 (the “Effective Date”) by and between MABTECH AB, formed under the laws of Sweden (“MAB”) and SEATTLE GENETICS, INC., a Delaware corporation (“SGI”).

RECITALS

A. MAB owns intellectual property rights relating to the S2C6 antibody (“S2C6”)

B. SGI desires to acquire access to S2C6 and an exclusive license to make, use offer for sale, sell, import or otherwise distribute products that embody S2C6.

C. MAB is willing to provide SGI with access to S2C6 and to grant SGI an exclusive license to make, use, offer for sale, sell, import or otherwise distribute products that embody S2C6 worldwide in accordance with the terms and conditions set forth in this Agreement.

AGREEMENT

The parties hereto agree as follows:

1. Definitions

“ Affiliate ” shall mean any corporation or other business entity controlled by, controlling, or under common control with another entity, with “control” meaning direct or indirect beneficial ownership of more than fifty percent (50%)  of the voting stock of such corporation, or more than a fifty percent (50%)  interest in the decision-making authority of such other unincorporated business entity; and a corporation in which the maximum amount of stock permitted by law to be held by another entity is beneficially owned by such other entity.

“ Confidential Information ” shall have the meaning assigned thereto in Section 10.

“ First Commercial Sale ” shall mean, with respect to any product, the first sale for use or consumption by the general public of such product in any country after all required marketing and pricing approvals have been granted, or otherwise permitted, by the governing health authority of such country. “First Commercial Sale” shall not include the sale of any Product for use in clinical trials or research.

“ Licensed Products ” shall mean any product incorporating the S2C6 antibody or derived from the S2C6 antibody or its sequence.

“ Licensed Technology ” shall mean all rights to the S2C6 including, but not limited to:

(a) the patents and patent applications currently existing or filed hereafter covering the S2C6, including any addition, continuation, continuation-in-part or division thereof or any substitute application therefor; and

(b) all trade secrets and other information, including but not limited to present and future techniques, inventions, discoveries, developments, practices, methods, formulations, specifications, processes, apparatus, knowledge, know-how, skill, biological materials, design data, pharmacological, toxicological and clinical test data, sequence data, analytical and quality control data, manufacturing data

and all other information and data relating to the S2C6 antibody.

“ Net Sales ” shall mean the amount actually received by SGI or its Affiliates or sublicensees for the sale to an unaffiliated third party of a Licensed Product, less the following deductions for amounts actually incurred related to the sale:

(a) normal, customary trade and cash discounts (including volume discounts), credits and rebates and allowances and adjustments for rejections, recalls or returns; and

(b) transportation and delivery charges actually incurred, including shipping, freight and insurance and all sales, use, excise, value-added and similar taxes or duties imposed on the sale and included in the amount invoiced.

In the event that a Licensed Product is sold as part of a Combination Product (as defined below), the Net Sales from the Combination Product, for the purposes of determining royalty payments, shall be determined by multiplying the Net Sales of the Combination Product (calculated using the standard Net Sales definition) during the applicable royalty reporting period by the fraction A/A+B, where A is the average sale price of the Product when sold separately in finished form and B is the average sale price of the other product(s) included in the Combination Product when sold separately in finished form, in each case during the applicable royalty reporting period or, if sales of both the Product and the other product(s) did not occur in such period, then in the most recent royalty reporting period in which sales of both occurred. In the event that such average sale price cannot be determined for both the Product and all other product(s) included in the Combination Product, Net Sales for the purposes of determining royalty payments shall be calculated by multiplying the Net Sales of the Combination Product (calculated using the standard Net Sales definition) by the fraction C/C+D, where C is the fair market value of the Product and D is the fair market value of all other pharmaceutical product(s) included in the Combination Product. In such event, SGI shall in good faith make a determination of the respective fair market values of the Product and all other pharmaceutical products included in the Combination Product, and shall notify MAB of such determination and provide MAB with data to support such determination. MAB shall have the right to review such determination and supporting data, and to notify SGI if it disagrees with such determination.

As used above, the term “Combination Product” shall mean any pharmaceutical product which comprises a Licensed Product and any other active compounds and/or ingredients.

Net Sales shall not include transfer of Licensed Products at or below cost by or on behalf of SGI in connection with research or clinical trials.

2. License Grant . Subject to the terms of this Agreement, MAB hereby grants to SGI and its Affiliates a worldwide exclusive license, with right to sublicense, to the Licensed Technology to make, use, offer for sale, sell, import, offer to import or otherwise distribute Licensed Products in all fields.

3. Reservation . The license granted in Section 2 is subject to rights reserved by MAB to use the Licensed Technology for research purposes only and to transfer the Licensed Technology to third parties for research purposes only provided such Licensed Technology bears a legend stating that such Licensed Technology may only be used for research purposes.

4. Payments

-2-

4.1 License Fee . SGI shall pay MAB a license fee of Forty Thousand U.S. Dollars (U.S.$40,000) within ten (10) days following the execution of this Agreement.

4.2 Milestone Payment . SGI shall pay MAB a one-time milestone payment of Seventy Thousand U.S. Dollars (U.S.$70,000) within thirty (30) days following SGI’s first filing of an investigational new drug application with the U.S. Food and Drug Administration, or an equivalent filing in one or more European countries, covering a Licensed Product.

4.3 Royalties

4.3.1 SGI shall pay MAB a royalty equal to two percent (2%) on Net Sales of Licensed Products, commencing with the First Commercial Sale of a Licensed Product.

4.3.2 Royalties shall be calculated on a calendar quarterly basis and shall be due and payable within sixty (60) days after the end of such calendar quarter. Such royalties shall be calculated on the Net Sales in the local currency of each country, and converted into U.S. Dollars and paid in U.S. Dollars, on the basis of the currency exchange rate published in the Wall Street Journal or comparable newspaper of international circulation on the last day of such preceding calendar quarter; provided, however, that royalties with respect to Net Sales denominated in U.S. Dollars shall be calculated in U.S. Dollars. SGI shall withhold any taxes on such royalties as required by law.

4.3.3 SGI shall furnish to MAB a written report which includes financial information relevant to the calculation of royalties, including the relevant, current standard list prices. Such reports shall be due together with the royalty payments under Section 4.3.1 within thirty (30) days after the end of each calendar quarter.

4.3.4 SGI shall, and SGI shall cause its Affiliates and sublicensees to, keep full, complete and proper records and accounts of Net Sales of Licensed Products in sufficient detail to enable the royalties payable to MAB to be determined by an independent audit. Upon reasonable notice to SGI, MAB shall have the right to have an independent certified public accountant audit SGI’s or its Affiliates’ records pertaining to Licensed Products during normal business hours to verify the royalties payable pursuant to this Agreement; provided , however , that (a) such audit shall not take place more frequently than once a year and (b) shall not cover such records for more than the preceding three (3) years. Such audits shall be at MAB’s expense unless such audit determines that SGI or any of its Affiliates has paid MAB less than ninety percent (90%) of the amount determined to be due for a given time period, in which case such audit shall be at SGI’s expense. SGI shall, and SGI shall cause its Affiliates and sublicensees to, preserve and maintain all such records and accounts required for audit for a period of three (3) years after the quarter to which such records and accounts apply.

5. Commercial Development

5.1 SGI shall, upon MAB’s request, keep MAB generally informed of SGI’s and its Affiliates’ updated development plans for Licensed Products, including SGI’s and its Affiliates’ and sublicensees’ planned timing for Licensed Product launch dates. All dates and other information provided by SGI to MAB shall be Confidential Information (as defined below), shall used by MAB for planning purposes only and shall be subject to modification by SGI, at any time, based on its or its Affiliates’ and sublicensees’ actual progress in the development process.

5.2 SGI shall provide MAB with notice of regulatory approvals received by SGI or its Affiliates or sublicensees’ regarding Licensed Products.

-3-

6. Governmental Approvals . SGI shall be responsible for obtaining all necessary governmental approvals for the development, testing, production, distribution, sale and use of Licensed Products, as applicable, in any country where Licensed Products shall be manufactured or sold or otherwise distributed. MAB agrees to provide SGI, at SGI’s expense, with any assistance reasonably requested by SGI, in obtaining such governmental approvals.

7. Representations and Warranties

7.1 Representations of SGI . SGI hereby represents and warrants to MAB as follows:

(a) SGI has full power and authority to enter into and perform this Agreement. This Agreement is a legal and valid obligation binding upon SGI and enforceable in accordance with its terms. The execution, delivery and performance of this Agreement by SGI does not conflict with any agreement, instrument or understanding, oral or written, to which it is a party or by which it is bound, nor violate any law or regulation of any court, governmental body or administrative or other agency having jurisdiction over it.

7.2 Representations of MAB . MAB hereby represents and warrants to SGI as follows:

(a) MAB has full power and authority to enter into and perform this Agreement and grant the rights granted to SGI hereunder. This Agreement is a legal and valid obligation binding upon MAB and enforceable in accordance with its terms. The execution, delivery and performance of this Agreement by MAB, including but not limited to the grant of the licenses set forth herein, does not conflict with any agreement, instrument or understanding, oral or written, to which it is a party or by which it is bound, nor violate any law or regulation of any court, governmental body or administrative or other agency having jurisdiction over it.

(b) MAB is the sole and exclusive owner of the Licensed Technology, free of any liens, encumbrances or ownership interests of any individual or entity, commercial, academic or otherwise. Neither the execution or delivery of this Agreement nor the consummation of the transactions contemplated hereunder requires MAB to obtain any permits, authorizations or consents from any governmental body or from any other body, person, form or corporation and such execution, delivery and consummation shall not result in the breach of or give rise to cause for termination of any agreement or contract to which SGI or its Affiliates may be a party. Neither MAB nor its Affiliates shall take any action after the Effective Date that would in any way restrict its legal right to grant to SGI the rights and licenses contemplated under this Agreement or otherwise conflict with such rights and licenses.

(c) To the best of its actual knowledge, the Licensed Technology does not infringe or conflict with any patent or other proprietary right of any third party and there is not claim or basis therefor that might limit the use of the Licensed Technology as provided in the license grants to SGI herein.

8. Intentionally Omitted

9. Limitation of Liability . IN NO EVENT WILL EITHER PARTY HERETO BE LIABLE FOR ANY SPECIAL, INCIDENTAL, CONSEQUENTIAL OR INDIRECT DAMAGES SUFFERED BY THE OTHER PARTY ARISING IN ANY WAY OUT OF THIS AGREEMENT, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, INCLUDING WITHOUT LIMITATION ANY

-4-

ACT OR FAILURE TO ACT OF ANY NATURE BY EITHER PARTY. THIS LIMITATION WILL APPLY EVEN IF THE PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

10. Confidentiality

10.1 “Confidential Information” shall mean any proprietary information that is specifically designated as such and that is disclosed by either party to the other in any form in connection with this Agreement. For a period of five (5) years from the date of disclosure, each party (a) shall treat as confidential all Confidential Information provided by the other party, (b) shall not use such Confidential Information except as expressly permitted under the terms of this Agreement or otherwise authorized in writing by the disclosing party, (c) shall implement reasonable procedures to prohibit the disclosure, unauthorized duplication, misuse or removal of such Confidential Information and (d) shall not disclose such Confidential Information to any third party. Without limiting the foregoing, each of the parties shall use at least the same procedures and degree of care to prevent the disclosure of Confidential Information as it uses to prevent the disclosure of its own confidential information of like importance, and shall in any event use no less than reasonable procedures and a reasonable degree of care.

10.2 Notwithstanding the above, neither party shall have liability to the other with regard to any Confidential Information that:

(a) was generally known and available to the public domain at the time it was disclosed, or becomes generally known and available to the public domain through no fault of the receiving party;

(b) was known to the receiver at the time of disclosure as shown by the receiving party’s written records in existence at the time of disclosure;

(c) is disclosed with the prior written approval of the disclosing party;

(d) becomes known to the receiving party from a source other than the disclosing party without breach of this Agreement by the receiving party and in a manner that is otherwise not in violation of the disclosing party’s rights;

(e) is disclosed as required by law, including without limitation any securities law, or pursuant to the order or requirement of a court, administrative agency, or other governmental body; provided , that the receiving party shall provide reasonable advance notice to enable the disclosing party to seek a protective order or otherwise prevent such disclosure; or

(f) is disclosed as required by law or regulation in obtaining government approval to import, distribute or use Licensed Products in the manner authorized under this Agreement.

11. Term and Termination

11.1 The term of this Agreement shall commence as of the Effective Date and shall continue in effect until (a) terminated in accordance with Section 11.2 or (b) the tenth (10th) anniversary of the First Commercial Sale (the “Tenth Anniversary Date”); provided however that on the Tenth Anniversary Date the license granted herein shall survive termination and become royalty-free, fully paid-up and perpetual.

-5-

11.2 Either party may terminate this Agreement in the event of a material breach of the Agreement by the other party upon ninety (90) days written notice to the other party. The termination shall become effective at the end of the ninety (90) day period unless the other party cures such breach within such period. Subject to Section 12, each party’s right to so terminate shall be in addition to any remedies available for breach of contract.

11.3 Neither expiration or termination shall relieve either party of its rights or obligations under Sections 8, 9, 10 or 12 or the license granted under Section 11.1(b). Further, SGI shall make all reports and payments as are required for the final quarter.

11.4 Within ten (10) days after the expiration or termination of this Agreement, each party shall return any Confidential Information received from the other party.

12. General Provisions

12.1 MAB and SGI shall be independent contractors and shall not be deemed to be partners, joint venturers or each other’s agents, and neither party shall have the right to act on behalf of the other except as is expressly set forth in this Agreement.

12.2 This Agreement sets forth the entire agreement and understanding between the parties and supersedes all previous agreements, promises, representations, understandings, and negotiations, whether written or oral between the parties with respect to the subject matter hereof. There shall be no amendments or modifications to this Agreement, except by a written document signed by both parties.

12.3 This Agreement shall not be assigned by either party without the prior written consent of the other party, except as part of a sale or transfer, by way of merger or otherwise, of all or substantially all of the business assets of such party to which this Agreement relates.

12.4 This Agreement shall be construed and enforced in accordance with the laws of the state of Washington, without giving effect to its or any other jurisdiction’s principles of conflicts of law. Any dispute or claim arising out of or in connection with this Agreement shall be resolved as follows: (a) for a period of thirty (30) days after a dispute arises the respective appropriate officers of the parties shall negotiate in good faith in an effort to resolve the dispute; and (b) if the dispute has not been resolved at the close of such thirty (30) day period, the matter will be finally settled by binding arbitration under the Rules of Arbitration of the American Arbitration Association, by one arbitrator appointed in accordance with said rules; provided , that if the parties cannot agree on the arbitrator, the dispute shall be resolved by a panel of three arbitrators, wherein each party shall appoint one arbitrator and those arbitrators shall in turn jointly appoint the third arbitrator. Judgment on an award rendered by an arbitrator or arbitrators may be entered in any court having jurisdiction. Notwithstanding the foregoing, the parties may apply to any court of competent jurisdiction for preliminary or interim equitable relief without breach of this arbitration provision. Such arbitration shall be held in Seattle, Washington.

12.5 If any provision of this Agreement is finally held to be invalid, illegal or unenforceable by a court of competent jurisdiction, the validity, legality and enforceability of the remaining provisions shall not be affected or impaired in any way.

12.6 Any delay in enforcing a party’s rights under this Agreement or any waiver as to a particular default or other matter shall not constitute a waiver of a party’s right to the future enforcement of its rights under this Agreement.

-6-

12.7 Any notice required or permitted by this Agreement to be given to either party shall be in writing and shall be deemed given when delivered personally, by confirmed telecopy to a fax number designated in writing by the party to whom notice is given, by delivery by a nationally recognized overnight courier service, or by registered, recorded or certified mail, return receipt requested, and addressed to the party to whom such notice is directed, at:

or at such other address or telecopy number as such party to whom notice is directed may designate to the other party in writing.

12.8 If the performance of this Agreement or any obligations hereunder is prevented, restricted or interfered with by reason of fire or other casualty or accident, strikes or labor disputes, war or other violence, any law, order, proclamation, ordinance, demand or requirement of any government agency, or any other act or condition beyond the control of the parties hereto, the party so affected, upon giving prompt notice to the other party shall be excused from such performance (other than the obligation to pay money) during such prevention, restriction or interference and the performance of any obligations of the party not so affected which obligations are directly dependent upon such performance by the affected party, shall be tolled during such period.

12.9 This Agreement may be signed in counterparts, each of which shall be deemed an original and all of which together shall constitute one instrument.

[Signature page fol1ows]

-7-

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

-8-

Exhibit 10.5

FIRST AMENDMENT

TO THE

LICENSE AGREEMENT

This First Amendment (the “Amendment”) to the License Agreement (“License Agreement”) is made effective as of January 31, 2000 (the “Effective Date”) by and between MABTECH AB, formed under the laws of Sweden (“MAB”) and SEATTLE GENETICS, INC., a Delaware corporation (“SGI”).

RECITALS

MAB and SGI entered into the License Agreement dated as of June 14, 1998 pursuant to which MAB agreed to provide SGI access to the S2C6 antibody and the exclusive license to make, use, offer for sale, sell, import or otherwise distribute products that embody the S2C6 antibody.

MAB and SGI now wish to amend the License Agreement in certain respects as hereinafter provided and in consideration for the amendments made herein, SGI shall pay MAB Twenty-five Thousand U.S. Dollars (U.S.$25,000) within ten (10) days of execution of this Amendment.

Except as otherwise provided herein, definitions of capitalized words shall be those set forth in the License Agreement.

The parties now agree as follows:

AMENDMENT

“4.2 Milestone Payment .    SGI shall pay MAB a one-time milestone payment of Seventy Thousand U.S. Dollars (U.S.$70,000) within thirty (30) days following SGI’s first filing of an investigational new drug application with the U.S. Food and Drug Administration, or an equivalent filing in one or more European countries, covering a Licensed Product. In addition, SGI shall pay MAB a one-time milestone payment of Fifty Thousand U.S. Dollars (U.S.$50,000) within thirty (30) days following the commencement of the first Phase III clinical trial covering a Licensed Product.”

“4.3.1 SGI shall pay MAB a royalty equal to one percent (1%) on net Sales of Licensed Products, commending with the First Commercial Sale of a Licensed Product.”

ENTIRE AGREEMENT

Except as provided otherwise herein, all other terms and conditions of the License Agreement shall remain in full force and effect.

IN WITNESS WHEREOF, the parties have executed this Amendment as of the date first above written.

Exhibit 10.6

LICENSE AGREEMENT

This License Agreement (the “Agreement”) is entered into and made effective the 20 ^th day of September, 1999 (the “Effective Date”) between UNIVERSITY OF MIAMI and its School of Medicine, whose principal place of business is at 1600 N.W. 10th Avenue, Miami, Florida 33136 (hereinafter referred to as “LICENSOR”) and Seattle Genetics, Inc., whose principal place of business is at 22215 26th Avenue S.E., Suite 3000, Bothell, Washington 98021, hereinafter referred to as “LICENSEE”).

WITNESSETH

WHEREAS, LICENSOR is the sole owner of the technology identified as an anti-CD3O antibody known as C1O and,

WHEREAS, LICENSOR may obtain a United States Patent, and foreign counterparts in the future; and,

WHEREAS, LICENSOR warrants that it possesses the right to license the aforestated technology and any patents to be obtained and the right to market the technology; and,

WHEREAS, LICENSOR wishes the LICENSEE to obtain any subject patents, and to market products developed based on the technology; and,

WHEREAS, LICENSEE desires to acquire an exclusive license in the Territory for all uses in human and animal diagnostics and therapeutics. with the right to sublicense, for the purposes of making, having made for its own use and sale, using and selling products and practicing any invention disclosed and claimed in the Patent Rights;

NOW THEREFORE, For these and other valuable considerations, the receipt of which is hereby acknowledged, the parties agree as follows:

1. DEFINITIONS:

1.1 “Affiliate” shall mean any corporation or other business entity controlled by, controlling or under common control with LICENSOR or LICENSEE. For this purpose, “control” shall mean direct or indirect beneficial ownership of at least a fifty percent (50%) of the voting stock of, or at least a fifty percent (50%) interest in the income of such corporation or other business entity, or such other relationship as in fact, constitutes actual control.

1.2 “Sublicensee” as used in this Agreement shall mean any third party to whom LICENSEE has granted a license to make, have made, use and/or sell the Product under the Patent Rights, provided said third party has agreed in writing with LICENSEE to accept the conditions and restrictions agreed to by LICENSEE in this Agreement.

1.3 “Patent Rights” shall mean United States Patent(s) to be obtained, or any new claim, re-examination, reissue or improvement or extension thereof, and the foreign counterpart patents, patent applications and patents issuing therefrom relating to the product.

1.4 “Product” shall mean any product or part thereof which contains, is derived from or is developed using the Technology.

1.5 “Technology” shall mean the anti-CD3O antibody known as C-10.

1.6 “Net Sales” shall mean the sum of all amounts invoiced, on account of sale or use of Products by LICENSEE and its Affiliates and any Sublicensees to non-affiliated third party purchasers or users of Products, less, if invoiced separately, (a) cash discounts to purchasers allowed in amounts customary in the trade, (b) amounts for transportation or shipping charges (including cost of insuring shipment) to purchasers, (c) credits for returns, allowances or trades, and (d) taxes and duties levied on the sale of Products, whether absorbed by Licensee or paid by the purchaser.

1.7 “Territory” shall mean worldwide

1.8 “Field of Use” shall mean any use in human and animal diagnostics and therapeutics.

1.9 “Know-how” shall mean any and all materials, data, results, formulae, designs, specifications, methods, processes, techniques, ideas, discoveries, technical information, process information, clinical information, and any other information, whether or not any of the foregoing is patentable, that are owned or controlled by LICENSOR as of the Effective Date or during the term of this Agreement to the extent that any of the foregoing relates to Technology or any Patent Rights or is necessary or useful for the research, development, manufacture or sale of any Product in the Field of Use in the Territory.

1.10 “Conjugated Product” shall mean a Product that includes an attachment of any other agent other than human immunoglobulin sequences.

1.11 “Non-Conjugated Product” shall mean any Product other than a Conjugated Product.

2. LICENSE GRANT; SUBLICENSING AND DELIVERY OF MATERIALS:

2.1 In consideration for payment of royalties, LICENSOR hereby grants to LICENSEE an exclusive license in the Territory for the Field of Use, with the right to sublicense, to the Technology and Know-how and under any Patent Rights, to research, develop, make, have made for its own use and sale, use, import, export, sell or offer to sell the Product and to practice the method of any invention claimed in the Patent Rights. In connection with the exclusive grant under this Section 2, LICENSOR agrees to provide the C 10 hybridoma and C 10 protein materials to LICENSEE within seven (7) from the Effective Date. LICENSOR further agrees to provide to LICENSEE and any sublicensee such other information and materials comprising the Technology, Know-how and the Patent Rights as it or they may reasonably request.

-2-

2.2 LICENSOR grants to the LICENSEE the authority to make application for Patents, in the name of the LICENSOR; all expenses of obtaining and maintaining said patents shall be paid by LICENSEE.

2.3 LICENSOR retains the right to practice such invention for its own internal research use.

2.4 LICENSOR agrees to provide the hamster anti-mouse CD3O hybridoma and protein to LICENSEE promptly after the Effective Date for LICENSEE’s own research use only.

2.5 LICENSEE shall have the right to grant sublicenses to the Technology, Know-how and Patent Rights without the prior approval of LICENSOR

3. TERM:

The license granted by this Agreement shall be Exclusive in the Licensed Field of Use for a term commencing as of the effective date of this Agreement and ending on the date ten (10) years from the date of first commercial sale of a Product(s) by LICENSEE; LICENSEE agrees to promptly inform LICENSOR in writing of the date of first commercial sale.

Thereafter, LICENSEE shall have in perpetuity a fully paid up, royalty-free, non-exclusive license to use the Technology, Know-how and practice the Patent Rights to use, market and sell Product without accounting to LICENSOR.

4. UNITED STATES LAWS:

4.1 This Agreement is subject to all of the terms and conditions of Public Law 96-5 17 as amended, and LICENSEE agrees to take all action necessary on its part as LICENSEE to enable LICENSOR to satisfy its obligation thereunder, relating to Invention(s).

4.2 It is understood that LICENSOR is subject to United States laws and regulations controlling the export of technical data, computer software, laboratory prototypes and other commodities (including the Arms Export Control Act, as amended and the Export Administration Act of 1979), and that its obligations hereunder are contingent on compliance with applicable United States export laws and regulations. The transfer of certain technical data and commodities may require a license from the cognizant agency of the United States Government and/or written assurances by LICENSEE that LICENSEE shall not export data or commodities to certain foreign countries without prior approval of such agency. LICENSOR neither represents that a license shall not be required nor that, if required, it shall be issued.

-3-

5. PATENT PROTECTION AND INFRINGEMENT:

5.1 LICENSEE, during the term of this Agreement, is responsible for the filing, payment and the prosecution of all patents and applications covering the Technology.

5.2 LICENSEE shall promptly notify LICENSOR in writing of any claim of Patent Rights infringement which may be asserted against LICENSEE or LICENSOR, its Affiliates and any sublicensees because of the manufacture, use, promotion and sale of Products.

5.3 LICENSEE will defend, indemnify and hold harmless LICENSOR, its Trustees, officers, directors, employees and its Affiliates against any and all judgments and damages arising from any and all third party claims of Patent Rights infringement which may be asserted against LICENSOR, and Affiliates because of the manufacture, use, promotion and sale of Products. LICENSEE will bear all costs and expenses incurred in connection with the defense of any such claims or as a result of any settlement made or judgment rendered on the basis of such claims. LICENSOR shall have no further liability to LICENSEE for any loss or damages LICENSEE may incur as a result of the invalidity of LICENSOR’S Patent Rights. LICENSOR will have the right, but not the obligation to retain counsel at its expense in connection with any such claim.

5.4 Upon learning of any infringement of Patent Rights by third parties in any country, LICENSEE and LICENSOR will promptly inform each other, as the case may be, in writing of that fact and will supply the other with any available evidence pertaining to the infringement. LICENSEE at its own expense shall have the option to take whatever steps are necessary to stop the infringement at its expense and recover damages therefore, and will be entitled to retain all damages so recovered. In the event that LICENSOR and LICENSEE mutually agree to bring suit, costs and expenses shall be shared equally and any recovery in excess of expenses shall be shared equally. In any event, no settlement, consent, judgment or other voluntary final disposition of the suit may be entered into without the consent of LICENSOR, which shall not be unreasonably withheld. In the event LICENSEE determines not to take steps to stop the infringement, LICENSEE will give notice to LICENSOR of such intent and LICENSOR shall have the right to take whatever steps are necessary to stop the infringement at its expenses and recover damages therefore, and will be entitled to retain all damages so recovered.

5.5 LICENSOR shall have no responsibility with respect to LICENSEE’S own trademarks and tradename, and LICENSEE in respect to the use thereof will defend, indemnify and hold harmless LICENSOR against any and all third party claims.

6. INDEMNIFICATION:

6.1 LICENSEE agrees to release, indemnify and hold harmless the LICENSOR, its Trustees, officers, faculty, employees and students against any and all losses, expenses, claims, actions, lawsuits and judgments thereon (including attorney’s fees through the appellate levels) which may be brought against LICENSOR, its Trustees, officers, faculty, employees or students as a result of or arising out of any negligent act or omission of LICENSEE, its agents, or employees, or arising out of use, production, manufacture, sale, lease,

-4-

consumption or advertisement by LICENSEE or its Sublicensees or third parties authorized by LICENSEE of any Patent Rights, Product or Technology licensed under this Agreement.

6.2 This Agreement to reimburse and indemnify under the circumstances set forth above shall continue after the termination of this Agreement.

7. WARRANTIES:

7.1 LICENSOR represents and warrants that it has the right to grant the licenses set forth in Section 2 and to disclose the Know-how set forth in this Agreement.

7.2 LICENSOR MAKES NO OTHER WARRANTIES, EXPRESS OR IMPLIED, AND HEREBY DISCLAIMS ALL SUCH WARRANTIES, AS TO ANY MATTER WHATSOEVER, INCLUDING, WITHOUT LIMITATION, THE CONDITION OF ANY INVENTION(S) OR PRODUCT, WHETHER TANGIBLE OR INTANGIBLE, LICENSED UNDER THIS AGREEMENT; OR THE MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE OF THE INVENTION OR PRODUCT; OR THAT THE USE OF THE LICENSED PRODUCT WILL NOT INFRINGE ANY PATENT, COPYRIGHTS, TRADEMARKS, OR OTHER RIGHTS. LICENSOR SHALL NOT BE LIABLE FOR ANY DIRECT, CONSEQUENTIAL, OR OTHER DAMAGES SUFFERED BY ANY LICENSEE OR ANY THIRD PARTIES RESULTING FROM THE USE, PRODUCTION, MANUFACTURE, SALE, LEASE, CONSUMPTION, OR ADVERTISEMENT OF THE PRODUCT.

The provisions of this Section shall continue beyond the termination of this Agreement.

8. ROYALTIES AND PAYMENTS:

8.1 In consideration of the license herein granted, LICENSEE shall pay royalties and payments to LICENSOR as follows:

(a) License Issue Fee of Ten Thousand Dollars ($10,000), which said License Issue Fee shall be deemed earned and due immediately upon the execution of this Agreement.

(b) License Maintenance Fees of $10,000 on January 1, 2003, $15,000 on January 1, 2004 and $25,000 on each January 1 thereafter while royalty payments are payable pursuant to Section 8.1(d); provided, however, that the License Maintenance Fee for a given year shall be creditable against any Running Royalties subsequently due during said year under subparagraph 8.1(d) below.

(c) Milestone payments of $40,000 upon first use of a Product in humans and $150,000 upon first FDA approval (or equivalent in another major country) of a Product for the first indication.

(d) Running Royalty in an amount equal to (i) four percent (4%) of the Net Sales of the Non-Conjugated Products and (ii) three percent (3%) of the Net Sales of the Conjugated Products.

-5-

8.2 The royalties otherwise due and payable by LICENSEE hereunder shall be reduced by an amount equal to the royalty amounts LICENSEE or any Sublicensee must pay to any third party with respect to the development, manufacture, import or export, use or sale of any Product; provided, however, that in no event shall the royalty payments due and payable to LICENSOR be reduced to less than fifty percent (50%) of the royalties set forth in Section 8.1(d).

8.3 All payments shall be made hereunder in U.S. dollars; provided however, that if the proceeds of the sales upon which such royalty payments are based are received by the LICENSEE in a foreign currency or other form that is not convertible or exportable in dollars, and the LICENSEE does not have ongoing business operations or bank accounts in the country in which the currency is not convertible or exportable, the LICENSEE shall pay such royalties in the currency of the country in which such sales were made by depositing such royalties in LICENSOR’S name in a bank designated by LICENSOR in such country. Royalties in dollars shall be computed by converting the royalty in the currency of the country in which the sales were made at the exchange rate for dollars prevailing at the close of the business day of the LICENSEE’S quarter for which royalties are being calculated as published the following day in the Wall Street Journal (or, if it ceases to be published, a comparable publication to be agreed upon from time to time by the parties), and with respect to those countries for which rates are not published in the Wall Street Journal, the exchange rate fixed for such date by the appropriate United States governmental agency.

8.4 In the event the royalties set forth herein are higher than the maximum royalties permitted by the law or regulations of a particular country, the royalty payable for sales in such country shall be equal to the maximum permitted royalty under such law or regulation.

8.5 In the event that any taxes, withholding or otherwise, are levied by any taxing authority in connection with accrual or payment of any royalties payable to LICENSOR under this Agreement, the LICENSEE shall have the right to pay such taxes to the local tax authorities on behalf of LICENSOR and the payment to LICENSOR of the net amount due after reduction by the amount of such taxes, shall fully satisfy the LICENSEE’S royalty obligations under this Agreement.

9. COLLABORATION AND DILIGENCE EFFORTS:

9.1 LICENSEE shall use its reasonable efforts to manufacture, market and sell the Products in the Territory and will exert its reasonable efforts to create a demand for the Products.

9.2 LICENSEE agrees to submit reports, upon LICENSOR’s request not more than once every six (6) months, as to its efforts to develop markets for the Licensed Products. Such reports shall include assurance by LICENSEE of its intent to actively develop commercial embodiments of the inventions of Licensed Patents and a summary of its efforts in this regard.

9.3 Licensee shall use reasonable efforts to conduct pre-clinical and clinical investigations on Product at LICENSOR.

-6-

9.4 LICENSOR agrees to make its employees available to participate in LICENSEE’s development meetings from time to time at LICENSEE’s request and expense.

10. REPORTS AND RECORDS:

10.1 Commencing one (1) year after the first sale, the LICENSEE shall furnish to LICENSOR a report in writing specifying during the preceding calendar quarter (a) the number or amount of Products sold hereunder by LICENSEE, and/or its Affiliates or sublicensees, (b) the total billings for all Licensed Products sold, (c) deductions as applicable in paragraph 1.6, (d) total royalties due, (e) names and addresses of all sublicensees. Such reports shall be due within sixty (60) days following the last day of each calendar quarter in each year during the term of this Agreement. Each such report shall be accompanied by payment in full of the amount due LICENSOR in United States dollars calculated in accordance with Section 8.1 hereof.

10.2 For a period of three (3) years from the date of each report pursuant to Paragraph 10.1, LICENSEE, shall keep records adequate to verify each such report and accompanying payment made to LICENSOR under this Agreement, and an independent Certified Public Accountant or Accounting Firm selected by LICENSOR and acceptable to LICENSEE may have access, on reasonable notice during regular business hours, not to exceed once per year, to such records to verify such reports and payments. Such Accountant or Accounting Firm shall not disclose to LICENSOR any information other than that information relating solely to the accuracy of, or necessity for, the reports and payments made hereunder. The fees and expense of the Certified Public Accountant or Accounting Firm performing such verification shall be borne by LICENSOR unless in the event that the audit reveals an underpayment of royalty by more than ten (10%) percent, the cost of the audit shall be paid by LICENSEE.

11. MARKING AND STANDARDS:

11.1 Prior to the issuance of patents on the Invention(s), LICENSEE agrees to mark and have sublicensees mark Licensed products (or their containers or labels) made, sold, or otherwise disposed of by it under the license granted in this Agreement with a proper patent notice as specified under the patent laws of the United States.

11.2 LICENSEE further agrees to maintain satisfactory standards in respect to the nature of the Product manufactured and/or sold by LICENSEE. LICENSEE, agrees that all Product manufactured and/or sold by it shall be of a quality which is appropriate to products of the type here involved. LICENSEE agrees that similar provisions shall be included by sublicenses of all tiers.

12. ASSIGNMENT:

12.1 This Agreement is not assignable by LICENSEE or by operation of law without the prior written consent of LICENSOR at its sole discretion; provided, however that LICENSEE may assign this Agreement without the consent of LICENSOR if such assignment is to an Affiliate or is part of the sale of all or substantially all of the business of LICENSEE.

-7-

12.2 This Agreement shall extend to and be binding upon the successors and legal representatives and permitted assigns of LICENSOR and LICENSEE.

Any notice, payment, report or other correspondence (hereinafter collectively referred to as “correspondence”) required or permitted to be given hereunder shall be mailed by certified mail or delivered by courier or hand to the party to whom such correspondence is required or permitted to be given hereunder. If mailed, any such notice shall be deemed to have been given when mailed as evidenced by the postmark at point of mailing. If delivered by courier or hand, any such correspondence shall be deemed to have been given when received by the party to whom such correspondence is given, as evidenced by written and dated receipt of the receiving party.

All correspondence to LICENSEE shall be addressed as follows:

Seattle Genetics, Inc.

22215 26th Avenue S.E., Suite 3000

Bothell, Washington 98021

Attention:        H. Perry Fell, Ph.D.

All correspondence to LICENSOR shall be addressed, in duplicate, as follows:

FOR NOTICE:

University of Miami

School of Medicine

Vice Provost for Research

1600 N.W. 10th Avenue

Miami, FL 33106

Attention:        Norman Altman, Ph.D.

Assistant Vice President

Business Affairs

327 Max Orovitz Building

1507 Levante Avenue

Coral Gables, Florida 33124-1432

Attention:        Mr. Alan J. Fish

FOR NOTICE AND PAYMENT:

Director

Office of Technology Transfer

P.O. Box 016960(M811)

Miami, FL 33101

Attention:        Dr. Gary S. Margules

Either party may change the address to which correspondence to it is to be addressed by notification as provided herein.

-8-

14. TERMINATION:

14.1 LICENSOR and LICENSEE shall have the right to terminate this Agreement if the other party commits a material breach of an obligation under this Agreement or provides a false report and continues in default for more than three (3) months after receiving written notice of such default or false report. Such termination shall be effective upon further written notice to the breaching party after failure by the breaching party to cure such default. If LICENSOR commits a material breach or defaults, then LICENSEE has no duty to continue the payment of royalties as set forth in Section 8 of this Agreement.

14.2 The license and rights granted in this Agreement have been granted on the basis of the special capability of LICENSEE to perform research and development work leading to the manufacture and marketing of the Products. Accordingly, LICENSEE covenants and agrees that in the event any proceedings under the Bankruptcy Act or any amendment thereto, be commenced by or against LICENSEE, and, if against LICENSEE, said proceedings shall not be dismissed with prejudice before either an adjudication in bankruptcy or the confirmation of a composition, arrangement, or plan of reorganization, or in the event LICENSEE shall be adjudged insolvent or make an assignment for the benefit of its creditors, or if a writ of attachment or execution be levied upon the license hereby created and not be released or satisfied within twenty (20) days thereafter, or if a receiver be appointed in any proceeding or action to which LICENSEE is a party with authority to exercise any of the rights or privileges granted hereunder and such receiver be so discharged within a period of sixty (60) days after his appointment, any such event shall be deemed to constitute a breach of this Agreement by LICENSEE and, LICENSOR, at the election of LICENSOR, but not otherwise, ipso facto, and without notice or other action by LICENSOR, shall terminate this Agreement and all rights of LICENSEE hereunder and all rights of any and all persons claiming under LICENSEE.

14.3 LICENSEE shall have the right to terminate this Agreement upon ninety (90) days notice.

14.4 Any termination of this Agreement shall be without prejudice to LICENSOR’s right to recover all amounts accruing to LICENSOR prior to such termination and cancellation. Except as otherwise provided, should this Agreement be terminated for any reason, LICENSEE shall have no rights, express or implied, under any patent property which is the subject matter of this Agreement (other than patent properties owned solely by LICENSEE), nor have the right to recover any royalties paid LICENSOR hereunder. Upon termination, LICENSEE shall have the right to dispose of Products then in their possession and to complete existing contracts for such products, so long as contracts are completed within twelve (12) months from the date of termination, subject to the payment of royalties to LICENSOR as provided in Section 7 hereof.

15. CERTIFICATE OF INSURANCE:

15.1 LICENSEE shall, commencing not later than ten (10) days prior to the first use in humans of a Product, maintain liability insurance coverage for the Product in the amount of five million dollars ($5,000,000) and at no expense to LICENSOR. LICENSEE shall

-9-

name LICENSOR as an additional insured. At the time of execution of this Agreement, LICENSEE shall provide a certificate of insurance to LICENSOR.

15.2 LICENSEE agrees to carry and keep in force, at its expense, general liability insurance with limits not less than $1,000,000 per person and $3,000,000 aggregate to cover liability for damages on account of bodily or personal injury or death to any person, or damage to property of any person. Such insurance shall contain an endorsement naming the University as an additional insured with respect to this Agreement. Insurance Certificates should be sent to the University of Miami, attention Mr. William Coombs, 333 Max Orovitz Building, 1507 Levante Avenue, Coral Gables, Florida 33 124-1437.

16. USE OF NAME:

LICENSEE shall not use the name of the University of Miami, or any of its employees, or any adaptation thereof, in any publication, including advertising, promotional or sales literature without the prior written consent of Mr. Alan J. Fish, Assistant Vice President of Business Services, 327 Max Orovitz Bldg., 1507 Levante Avenue, Coral Gables, FL 33 124-1432.

17. CONFIDENTIALITY AND NON-DISCLOSURE:

17.1 Any and all information in any form relating to the Technology, Know-how or Patent Rights furnished to either party (or its agents or employees) by the other party (or its laboratories or agents or employees), including but not limited to information regarding or relating to devices, biological materials, methods, processes, data, drawings, documentation, patent applications, know how and product development plans, is confidential, proprietary, information and any and all such information is hereinafter referred to as “Proprietary Information.”

17.2 Exceptions to Proprietary Information. As used herein, “Proprietary Information” does not include information:

(a) that at the time of disclosure to the receiving party is or later becomes generally available to the public through no fault of the receiving party;

(b) that is demonstrated to have been in the receiving party’s possession prior to the time of disclosure by the disclosing party;

(c) that is demonstrated by a preponderance of the evidence to have been independently developed by the receiving party’s personnel without reference to Proprietary Information of the disclosing party; and

(d) received from a third party, unless such information is obtained subject to a confidential disclosure agreement.

17.3 Use of Proprietary Information. Each party agrees: (a) to hold in strict confidence and trust and maintain as confidential all Proprietary Information disclosed by the

-10-

other party; (b) not to disclose any such Proprietary Information or any information derived therefrom to any person, except to those employees or legal counsel of the receiving party who are required to receive the Proprietary Information for the purposes described in this Agreement and who are bound by the provisions of this Agreement; and (c) to use the Proprietary Information only for the purposes described in this Agreement.

17.4 Ownership of Proprietary Information. Each party agrees that all Proprietary Information disclosed by the other party’ will at all times be and remain the sole property of the disclosing party and the disclosing party is the sole owner of all patents, copyrights and other intellectual property rights and other proprietary rights related to the Proprietary Information disclosed by it and conceived or made by the disclosing party’s employees.

17.5 Term of Confidentiality. The obligations of confidentiality provided herein shall continue in force and effect for five (5) years from the date of termination of this Agreement, whether by lapse of the Term hereof or otherwise, unless extended or limited by mutual agreement executed in writing by an officer of each party.

18. GOVERNING LAW:

This Agreement shall be governed by and interpreted in accordance with the laws of the State of Florida.

19. CAPTIONS:

The captions and paragraph heading of this Agreement are solely for the convenience of reference and shall not affect its interpretation.

20. SEVERABILITY:

Should any part or provision of this Agreement be held unenforceable or in conflict with the applicable laws or regulations of any jurisdiction, the invalid or unenforceable part or provision shall be replaced with a provision which accomplishes, to the extent possible, the original business purpose of such part or provision in valid and enforceable manner, and the remainder of the Agreement shall remain binding upon the parties hereto.

21. SURVIVAL:

21.1 The provisions of Sections 5, 6 and 7 shall survive the termination or expiration of this Agreement and shall remain in full force and effect.

21.2 The provisions of this Agreement which do not survive termination or expiration hereof (as the case may be) shall, nonetheless, be controlling on, and shall be used in construing and interpreting, the rights and obligations of the parties hereto with regard to any dispute, controversy or claim which may arise under, out of, in connection with, or relating to this Agreement.

-11-

22. AMENDMENT:

No amendment or modification of the terms of this Agreement shall be binding on either party unless reduced to writing and signed by an authorized officer of the party to be bound.

23. WAIVER:

No failure or delay on the part of a party in exercising any right hereunder will operate as a waiver of, or impair, any such right. No single or partial exercise of any such right will preclude any other or further exercise thereof or the exercise of any other right. No waiver of any such right will be deemed a waiver of any other right hereunder.

24. ENTIRE AGREEMENT:

This Agreement constitutes the entire agreement between the parties hereto respecting the subject matter hereof, and supercedes and terminates all prior agreements respecting the subject matter hereof, whether written or oral, and may be amended only by an instrument in writing executed by both parties hereto.

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed by their respective officers thereunto duly authorized to be effective as of the Effective Date.

-12-

Exhibit 10.7

AMENDMENT NO. 1 TO LICENSE AGREEMENT

BETWEEN

UNIVERSITY OF MIAMI

AND

SEATTLE GENETICS, INC.

This Amendment No. 1 to License Agreement (the “Amendment”) is made as of August 4, 2000 by and between University of Miami and its School of Medicine, whose principal place of business is at 1600 N.W. 10 ^th Avenue, Miami, Florida 33136 (“Licensor”), and Seattle Genetics, Inc., a Delaware corporation having offices at 22215 26 ^th Avenue SE, Bothell, WA 98021 (“Licensee”).

WHEREAS, Licensor and Licensee are parties to that certain License Agreement dated September 20, 1999 (the “ Agreement ”)

WHEREAS, Licensor and Licensee wish to amend the Agreement as set forth in this Amendment;

NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties agree as follows:

The Parties, intending to be legally bound, have caused this Amendment to be executed by their authorized representatives on the dates set forth below.

[*] Confidential treatment requested

Exhibit 10.8

LICENSE AGREEMENT

No. 651-O1.LIC

THIS AGREEMENT (the “Agreement”), made this 3 ^rd day of February, 2000 (the “EFFECTIVE DATE”), is by and between the ARIZONA BOARD OF REGENTS, a body corporate of the State of Arizona, acting on behalf of and for ARIZONA STATE UNIVERSITY, of Tempe, Arizona (“ASU”) and Seattle Genetics, Inc., a corporation organized under the laws of Delaware having its principal place of business located at 22215 26 ^th Avenue SE, Bothell, Washington 98021 (“LICENSEE”).

RECITALS

AGREEMENT

DEFINITIONS

Under ASU Case No.  651 :

U.S. Patent No. 5,635,483 entitled “Tumor Inhibiting Tetrapeptide Bearing

Modified Phenethyl Amides”.

For the purposes of this Agreement, only those compounds taught in the above named patent and identified as stereoisomers of a compound commonly referred to as “Auristatin E” are included in this license and the grant of rights described in Article 2 of this Agreement shall pertain only to the following:

Auristatin E, Compound No. 1S2R

Auristatin E, Compound No. 1R2R

Auristatin E, Compound No. 1S2S

Auristatin E, Compound No. 1R2S

Each of which falls within the general structure shown below :

-2-

and any corresponding extensions or foreign applications or patents.

-3-

2. GRANT

3. SUB-LICENSES

-4-

4. LICENSE ISSUE FEE AND MILESTONE PAYMENTS

5. PAYMENTS AND ROYALTIES

$100,000.00

-5-

$100,000.00

$250,000.00

$250,000.00

The LICENSEE shall pay to ASU a minimum annual royalty of $50,000 for the life of VALID CLAIMS of ASU’s PATENT RIGHTS (the “Minimum Annual Royalty”), beginning in the year of LICENSEE’s first receipt of marketing approval for a LICENSED PRODUCT from the US Food and Drug Administration (“US FDA”) or any other analogous worldwide regulatory agency. LICENSEE shall account to ASU and pay royalties to ASU semi-annually within forty-five (45)  days after the end of each calendar half-year for the just preceding calendar half-year. Concurrent with the final royalty payment, due on February 15 following any year, LICENSEE shall make an additional payment if necessary in order to meet its obligation to make minimum royalty payments

-6-

for that year.

•   February 15

•   August 15

-7-