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                                LICENSE AGREEMENT


         THIS license agreement (hereinafter "LICENSE") is made between THE DOW
CHEMICAL COMPANY (hereinafter "DOW" or a "Party"), a corporation duly formed and
existing under the laws of the State of Delaware, having a place of business at
2030 Dow Center, Midland, Michigan 48674, United States of America, and NeoRx
CORPORATION (hereinafter "NEORX" or a "Party"), a corporation duly formed and
existing under the laws of the State of Washington, having a place of business
at 410 West Harrison, Seattle, Washington 98119;

         WITNESSETH:

         WHEREAS, DOW is engaged in certain research and development projects
involving certain [*] for various pharmaceutical applications, including bone
marrow suppression and ablation; and

         WHEREAS, DOW has proprietary rights in technology relating to said
agents, including: patent rights, know-how, compounds, animal safety and
efficacy, clinical trial data, and various industrial property rights, including
those sublicensed from others; and

         WHEREAS, NEORX desires to undertake the further development and
commercial exploitation of said agents; and

         WHEREAS, NEORX desires to obtain an exclusive license for DOW's
technology relating to said agents; and

         WHEREAS, DOW is willing to grant said license to NEORX;

         WHEREAS, in connection with said license, DOW and NEORX desire to
provide for a transition in the development of the agents; and

         WHEREAS, DOW and NEORX have signed an Option Agreement, effective [*]
which Option Agreement was exercised on [*] and its license terms are deemed to
be met by the terms included in this LICENSE.

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         NOW, THEREFORE, DOW and NEORX, in consideration of the mutual covenants
contained herein, hereto agree as follows:

                             ARTICLE 1 - DEFINITIONS

         When used in this LICENSE, the following terms shall have the meanings
set out below, unless the context requires otherwise. The singular shall be
interpreted as including the plural and vice versa, unless the context clearly
indicates otherwise.

1.1      "AFFILIATE" means a corporation or any other entity that at any time
         during the term of this LICENSE directly or indirectly through one or
         more intermediaries is CONTROLLED by the designated Party, but only for
         so long as the relationship exists. A corporation or other entity shall
         no longer be an AFFILIATE when through loss, divestment, dilution or
         other reduction of a Party's ownership or control, the Party loses
         CONTROL of such corporation or other entity.

1.2      "ADDITIONAL AGENT" means [*] including their
         pharmaceutically-acceptable salts.

1.3      "AGENT" means [*] including its pharmaceutically-acceptable salts.

1.4      "APPROVAL" means final approval, in a country in the TERRITORY, by all
         REGULATORY AUTHORITIES in that country, for commercial marketing of
         PRODUCT, including for example, approval of final labeling and price
         approval. If no approval is required to market a PRODUCT in a
         particular country in the TERRITORY, then APPROVAL of the PRODUCT is
         deemed to have occurred in that country upon the first sale of a
         PRODUCT in that country to a THIRD PARTY.

1.5      "CDA" means the Confidential Disclosure Agreement between the Parties,
         effective May 22, 1997 (copy attached hereto for reference only as
         EXHIBIT A).

1.6      "COMBINATION PRODUCT" means a PRODUCT or AGENT sold together with or
         for use with another component; provided, however, that, for purposes
         of this definition, "[*]. NEORX must notify DOW promptly of any
         commercial sale of such COMBINATION PRODUCT and identify the other
         component for computation of the royalty.

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1.7      "COMPETITION" means the commercial sale of COMPETITIVE PRODUCTS, which
         sales, in the aggregate, constitute [*] of NEORX's NET SALES in such
         country. NEORX must promptly notify DOW in writing of the occurrence of
         such COMPETITION and must supply evidence of such COMPETITION.

1.8      "COMPETITIVE PRODUCT" means a PRODUCT, AGENT or GENERIC PRODUCT sold or
         used in the FIELD, including off label sale or use in the FIELD, [*].

1.9      "CONFIDENTIAL INFORMATION" means any proprietary information of either
         Party that is submitted to the other Party hereunder, including, but
         not limited to, TECHNOLOGY, PATENTS, or PROCESS PATENTS, any samples of
         AGENT or PRODUCT, financial terms of this LICENSE, and business
         development plans for the PRODUCT, and does not include information
         excluded under Article 6.2.

1.10     "CONTROL" or "CONTROLLED" shall mean, in the case of a corporation,
         ownership or control, directly or indirectly, of more than fifty
         percent (50%) of the shares of stock entitled to vote for the election
         of directors and, in the case of an entity other than a corporation,
         ownership or control, directly or indirectly, of more than fifty
         percent (50%) of the assets or the ability, in the case of either a
         corporate or non-corporate entity, to direct the management and affairs
         of such entity.

1.11     "[*]" means [*] and its salts.

1.12     "DEFENSIVE PATENTS" means those patent applications and patents listed
         on APPENDIX D attached hereto and made a part hereof, together with all
         continuations, registrations, confirmations, extensions, issuances, and
         foreign counterparts of the foregoing, and where relevant to the FIELD
         for GENERIC PRODUCT, AGENT or PRODUCT, including continuations-in-part,
         divisions, reissues, patents-of-addition of the foregoing. The Parties
         may review the list in APPENDIX D and discuss whether the patent
         applications and patents in the TERRITORY have become relevant to
         NEORX's FIELD and NEORX's business related thereto. With DOW's consent,
         NEORX may elect to move patent applications or patents from APPENDIX D
         to APPENDIX A.

1.13     "DOE" means the United States Department of Energy and corresponding
         agencies of other countries in the TERRITORY.

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1.14     "[*]" means [*], including its pharmaceutically-acceptable salts.

1.15     "EFFECTIVE DATE" means June 30, 1999.

1.16     "EUROPE" means all countries of western Europe and middle Europe,
         specifically, Albania, Austria, Belgium, Bulgaria, Croatia, Czech
         Republic, Denmark, Finland, France, Germany, Gibraltar, Greece,
         Guernsey, Hungary, Ireland, Isle of Man, Italy, Jersey, Latvia,
         Liechtenstein, Lithuania, Luxembourg, Macedonia, Monaco, Netherlands,
         Norway, Poland, Portugal, Romania, Serbia, Slovak Republic, Slovenia,
         Spain, Sweden, Switzerland and United Kingdom.

1.17     "FDA" means the United States Food and Drug Administration or any
         successor U.S. governmental agency performing similar functions.

1.18     "FIELD" means the IN VIVO use in human therapeutic applications that
         results in [*] which applications are expected to be administered in
         conjunction with or followed by treatments for [*]. Therefore, this
         FIELD is understood by the Parties to include the IN VIVO use [*].
         Furthermore, this FIELD is understood by the Parties to NOT include
         [*].

1.19     "GENERIC PRODUCT" means a product composed of a [*] complexed with [*].

1.20     "GMPs" means the Good Manufacturing Practices as defined from time to
         time in the Federal Food, Drug, and Cosmetic Act and related
         regulations or any successor laws or regulations governing the
         manufacture of the PRODUCT in the United States.

1.21     "HMOs" means health maintenance organizations and similar organizations
         which provide group medical payment in the United States of America.

1.22     "HOLMIUM" or "Ho" means all isotopes of the element holmium, including
         Holmium-166 or 166Ho.

1.23     "NET SALES" shall mean the amount invoiced on sales of PRODUCT or AGENT
         (or as calculated in accordance with Article 5.3.3, sales of
         COMBINATION PRODUCT) that are royalty bearing under Article 5 by NEORX
         and its

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         AFFILIATES and sublicensees to a THIRD PARTY, less the following
         deductions to the extent included in the amounts invoiced:

         (i)      [*].

         (ii)     [*].

         (iii)    [*].

         (iv)     [*].

         (v)      [*].

         (vi)     [*].

         NET SALES shall NOT include sales between or among NEORX and its
         AFFILIATES and sublicensees, except sales of those PRODUCT or AGENT
         that [*]. Also NET SALES shall NOT include sales for [*].

1.24.     "NEORX's FIELD" means the IN VIVO use in human therapeutic
          applications that results in [*], which applications are expected to
          be and shall be described in the package insert (subject to FDA
          approval) to be administered in conjunction with or followed by
          treatments for [*]. Therefore, NEORX's FIELD is understood by the
          Parties to include the IN VIVO use [*]. Furthermore, NEORX's FIELD is
          understood by the Parties to NOT include [*].

1.25.     "NRC" means the United States Nuclear Regulatory Commission and, for
          other countries in the TERRITORY, the corresponding governmental
          agencies for such regulations.

1.26.     "OPTION" means the Option Agreement signed between the Parties,
          effective [*], as amended, that was exercised on [*] (copy attached
          for reference purposes as EXHIBIT B).

1.27.    "ORPHAN DRUG" means the use of PRODUCT that qualifies under 57 CFR
         62085 (December 29, 1992), Part 316.

1.28.    "PATENTS" means all patent applications and patents in the TERRITORY to
         which DOW has rights, together with any continuations,
         continuations-in-part,

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         divisions, reissues, registrations, confirmations, patents-of-addition,
         and extensions of the foregoing, with any claims covering an AGENT,
         PRODUCT or use, or manufacture of AGENT or PRODUCT in NEORX's FIELD
         in the TERRITORY and which are owned, licensed or controlled by DOW,
         or, [*]. The current PATENTS are listed in APPENDIX A (as attached
         hereto and made a part hereof). APPENDIX A shall be updated from
         time to time, at NEORX's request, but no more frequently than once
         yearly after all patents have issued, and until all patents for a
         given family have issued such reports shall be quarterly, unless
         required sooner to provide information to compute the payments due
         under this LICENSE. After first APPROVAL of a PRODUCT in NEORX's
         FIELD in the TERRITORY, the Parties may review the list in
         APPENDIX A and discuss whether the patent applications and patents in
         the TERRITORY continue to be relevant to NEORX's FIELD and NEORX's
         business related thereto. With DOW's consent, NEORX, may or may not
         elect to move patent applications or patents from APPENDIX A to
         APPENDIX D.

1.29.    "PROCESS" means process[*], but does not include [*].

1.30.    "PROCESS PATENTS" means all patent applications and patents in the
         TERRITORY to which DOW has rights, together with any continuations,
         continuations-in-part, divisions, reissues, registrations,
         confirmations, patents-of-addition, and extensions of the foregoing,
         with any claims that cover [*] and which are owned, licensed or
         controlled by DOW, or which become owned, licensed or controlled by DOW
         during the term of this LICENSE. The current PROCESS PATENTS are listed
         in APPENDIX B (as attached hereto and made a part hereof). APPENDIX B
         shall be updated from time to time, at NEORX's request, but no more
         frequently than once yearly after all patents have issued, and until
         all patents for a given family have issued such reports shall be
         quarterly, unless required sooner to provide information to compute the
         payments due under this LICENSE.

1.31.    "PRODUCT" means any pharmaceutical preparation in finished dosage form
         containing an AGENT as the active drug substance for use in NEORX's
         FIELD.

1.32.    "REGULATORY AUTHORITY" means the agency corresponding to the FDA of
         each country in the TERRITORY and any other agency in the country from
         which

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         APPROVAL is required in order to commercially market a PRODUCT,
         including approval of final labeling and price approval.

1.33.    "SIGNATURE DATE" means the date of the last signature of the Parties to
         this LICENSE.

1.34.    "TECHNOLOGY" means data, information and process know-how relating to
         an AGENT, PRODUCT or PROCESS which DOW owns or possesses as of the
         EFFECTIVE DATE (or which DOW develops for NEORX under the OPTION
         through June 30, 1999) and which are described in APPENDIX E attached
         hereto and made a part hereof.

1.35.    "TERRITORY" means the all countries in the world, excluding Australia
         and its possessions.

1.36.    "THIRD PARTY" means anyone, other than DOW, NEORX or their respective
         AFFILIATES. Thus THIRD PARTY includes, without limitation, physicians,
         hospitals, clinics, hospice facilities, patients, distributors,
         formularies, and radiopharmacies.

1.37     "[*]" means the Curators of the [*].

1.38     "VALID CLAIM" means any claim of an issued patent included in a PATENT,
         or PROCESS PATENT, which has not been held unenforceable or invalid by
         a decision of a court or governmental agency of competent jurisdiction
         from which no appeal is or can be taken or which has not been admitted
         to be unenforceable or invalid through reissue, disclaimer or
         otherwise.



                          ARTICLE 2 - GRANT OF LICENSES

2.1      GRANT OF LICENSES - DOW hereby grants to NEORX, and NEORX hereby
         accepts:

         (a)      an EXCLUSIVE license to use the TECHNOLOGY to make, have made,
                  use, sell, have sold, offer to sell, export and import AGENT
                  and PRODUCT in the TERRITORY in NEORX's FIELD;

         (b)      an EXCLUSIVE license under the PATENTS to make, have made,
                  use, sell, have sold, offer to sell, export and import AGENT
                  and PRODUCT in the TERRITORY in NEORX's FIELD;

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         (c)      a NON-EXCLUSIVE license to use the PROCESS to make or have
                  made, in the TERRITORY, [*] to make AGENT and PRODUCT for
                  use in NEORX's FIELD in the TERRITORY; and

         (d)      a NON-EXCLUSIVE license under the PROCESS PATENTS to make or
                  have made, in the TERRITORY, [*] or AGENT to make AGENT and
                  PRODUCT for use in NEORX's FIELD in the TERRITORY;

         These licenses under (a) and (b) above shall be fully exclusive, to the
         exclusion of DOW and its AFFILIATES, but subject to Article 2.3, and
         only so long as this LICENSE is in effect.

         This grant shall also include ADDITIONAL AGENT to make the
         corresponding PRODUCT, providing [*].

2.2      SUBLICENSING - Subject to Articles 2.4 and 2.5, the licenses granted
         under Article 2.1 to NEORX include the right to sublicense THIRD
         PARTIES and NEORX's AFFILIATES. NEORX will make and will be responsible
         for all payments to DOW as a result of sublicensee and AFFILIATE sales
         of PRODUCT in the TERRITORY. NEORX will also be responsible for the
         observance by all sublicensees of all applicable provisions of this
         LICENSE, and will [*] cause all sublicensees to observe the covenants
         in this LICENSE [I.E., regarding confidentiality, maintenance of
         records and reporting of NET SALES and royalty payments, exchanges of
         information, governmental regulations (E.G., export licenses and NRC or
         DOE issues) and adverse reaction information]. All such sublicenses
         shall be in writing.

2.3      RESERVATIONS - DOW reserves the following rights.

         2.3.1    DOW reserves the right to make, have made, export and use
                  [*], AGENT or PRODUCT in NEORX's FIELD in the TERRITORY for
                  the purposes of:

                  (i)      process research;

                  (ii)     basic research and development;

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                  (iii)    supply to NEORX under such supply agreements as may
                           be agreed upon in writing between the Parties;

                  (iv)     supply [*] in Australia; as needed to continue
                           support of clinical trials referred to in
                           Articles 3 and 4; support NEORX under separate
                           service agreements as may be agreed upon in writing
                           between the Parties; and

                  (v)      publication of results obtained prior to the
                           EFFECTIVE DATE.

         2.3.2    DOW reserves the right, solely at it option and expense, to do
                  research or development on GENERIC PRODUCT, AGENT, PRODUCT and
                  PROCESS for non-commercial purposes in NEORX's FIELD in the
                  TERRITORY and for commercial purposes in NEORX's FIELD outside
                  the TERRITORY.

         2.3.3    Subject to Articles 11.4 and 11.5, DOW reserves the right for
                  DOW to proceed, solely at its option and expense, to research,
                  develop, make, have made, use, sell, export, import, have sold
                  and license in the TERRITORY OUTSIDE NEORX's FIELD:

                  (i)      [*]; and

                  (ii)     complexes of [*] with any metal, excluding
                           HOLUMIUM; and

                  (iii) complexes of other ligands with [*].

2.4        SUPPLY OF [*] - FOR PRODUCT FOR NEORX - DOW and NEORX may enter
           into a separate commercial supply agreement under which DOW will
           supply NEORX's requirements of [*] on mutually agreed terms and
           conditions. This Article 2.4 shall not imply an obligation on either
           Party to enter into a commercial supply agreement with the other
           Party. Before seeking a THIRD PARTY supplier for [*], NEORX shall
           notify DOW of NEORX's desire to get a supplier for [*]. DOW can
           either decline to make a proposal to supply [*] or make and discuss
           a proposal for supplying [*]; provided, however, that, whether or
           not DOW makes and discusses a proposal with NEORX, NEORX shall be
           free after [*] from its notice to DOW to enter into agreements with
           THIRD PARTIES any time in the future for the supply of [*]. NEORX

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<PAGE>

           shall notify DOW in accord with Article 15.1 whether it does or does
           not obtain such a supply agreement from DOW.

2.5        CONVEYANCE OF TECHNOLOGY BY DOW - Within thirty (30) days after the
           SIGNATURE DATE, Dow shall convey the TECHNOLOGY listed on APPENDIX E
           to NEORX; provided, however, that TECHNOLOGY developed by DOW through
           the EFFECTIVE DATE under the OPTION may be conveyed by July 30, 1999.
           In the event NEORX needs assistance in making or using [*], AGENT
           or PRODUCT in NEORX's FIELD or in using the TECHNOLOGY in NEORX's
           FIELD, the PARTIES may enter into a separate service agreement. NEORX
           agrees that the TECHNOLOGY listed on APPENDIX E is the entire
           obligation for transfer of TECHNOLOGY by DOW and that all items
           listed on APPENDIX E have been received and need not be further
           submitted at any time.

2.6      ADDITIONAL AGENT(S) - As soon as possible after the SIGNATURE DATE and
         at NEORX's request, DOW shall [*]. [*].

2.7      [*] - DOW has the possibility to provide a [*].

2.8      DEFENSIVE PATENTS - NEORX, its AFFILIATES and sublicensees may NOT
         commercially practice under DEFENSIVE PATENTS.



            ARTICLE 3 - NEORX DEVELOPMENT, OTHER ACTIVITY, DILIGENCE

3.1      DEVELOPMENT AND MARKETING EFFORTS FOR PRODUCT - NEORX shall use its
         reasonable and diligent efforts to carry out remaining developmental
         work on PRODUCT, as it believes necessary, and to file applications
         with the REGULATORY AUTHORITIES as NEORX deems necessary. For purposes
         of this LICENSE, "reasonable and diligent efforts" shall mean efforts
         reasonably consistent with those efforts used by NEORX with regard to
         its developmental work and commercial activities for its own products
         deemed to have similar commercial potential, consistent with its
         business, research and development practices, and applicable legal and
         regulatory requirements. NEORX has given DOW a copy of NEORX's schedule
         for development of a PRODUCT for the

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         United States and shall give DOW within [*] after the SIGNATURE DATE
         a schedule for development of the PRODUCT for the European market.
         NEORX shall keep such schedules updated through the time it is to
         provide reports under Article 3.2. Such schedules represent NEORX's
         current intentions, based on part on input from regulatory and
         other authorities, and estimated time frames for development of
         PRODUCT.

         For NEORX to have been deemed by DOW to have used its reasonable and
         diligent efforts, DOW expects that NEORX should:

         (a)      [*].

         (b)      Continue the clinical trials for the PRODUCT that are in
                  progress.

         (c)      File with the FDA for APPROVAL of the PRODUCT within [*] of
                  the successful conclusion of the clinical trials in the US if
                  the PRODUCT is commercially viable, where conclusion of the
                  clinical trials includes [*].

         (d)      Initiate commercial sales in the United States of PRODUCT
                  within [*] after APPROVAL in the United States, if the PRODUCT
                  is commercially viable.

         It is recognized that performance under this Article 3.1 is subject to
         Article 13.

3.2      DEVELOPMENT PROGRESS REPORTS - NEORX will provide DOW with [*] reports
         (reports to be verbal with one written annual report per year) of its
         development and registration activity, including submission(s) to
         REGULATORY AUTHORITIES and APPROVAL(s) in the TERRITORY, until a
         PRODUCT is commercially launched for NEORX's FIELD in the United States
         and Europe. Such reports will provide sufficient information to allow
         the evaluation of at least:

         (a)      NEORX's preclinical, clinical and registration activities for
                  a PRODUCT;

         (b)      the relationship of those activities under (a) above to
                  NEORX's development schedule shown for the PRODUCT for the
                  United States and Europe;

         (c)      NEORX's level of efforts at developing and registering a
                  PRODUCT; and

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<PAGE>

         (d)      notice of any APPROVAL obtained.

3.3      CLINICAL AND PRECLINICAL STUDIES - NEORX shall carry out such further
         studies of AGENT and PRODUCT as it deems necessary or advisable to
         develop the PRODUCT and in order to file such forms for APPROVAL with
         the REGULATORY AUTHORITIES for commercialization in the TERRITORY.
         NEORX is having clinical trials performed at [*] pursuant to an
         agreement between NEORX and [*]. DOW shall terminate its agreement(s)
         with [*] with respect to clinical trials for AGENT and PRODUCT and
         shall be responsible for any charges or costs in connection with such
         agreement(s).

3.4      NEORX RESPONSIBILITY - NEORX shall be solely responsible for the
         planning, design and execution of all its developmental work and
         commercialization with AGENT and PRODUCT for the TERRITORY after the
         EFFECTIVE DATE.

3.5      REGULATORY COSTS - All regulatory costs for NEORX's APPROVALS in the
         TERRITORY shall be borne by NEORX after the EFFECTIVE DATE.

3.6      FUTURE RESEARCH - Upon the SIGNATURE DATE, NEORX agrees that any
         research conducted by DOW on AGENT or PRODUCT at NEORX's written
         request outside of the OPTION or after June 30, 1999 shall be paid by
         NEORX at a rate to be negotiated by the Parties at the time of or
         before the request. Any research conducted by DOW on AGENT or PRODUCT
         after the SIGNATURE DATE shall be in accord with Articles 2.3, 2.4 and
         2.5. At its expense, DOW will draft any resulting patent applications
         and/or retain title to the patents conceived or reduced to practice
         during this LICENSE where DOW employees are the sole inventors, but
         NEORX will be exclusively licensed under this LICENSE for the TERRITORY
         for NEORX's FIELD so long as this LICENSE is in effect.



                            ARTICLE 4 - PATENT RIGHTS

4.1      DOW TO MAINTAIN PATENTS AND PROCESS PATENTS - DOW shall have the
         obligation and be responsible at its own cost and expense for
         prosecuting the patent applications in PATENTS and PROCESS PATENTS and
         for maintaining, extending and defending the patents in the PATENTS and
         PROCESS PATENTS for the term of this LICENSE. DOW shall use good faith
         efforts to prosecute, issue, maintain, extend and defend all PATENTS
         and PROCESS PATENTS. Should any PATENT or PROCESS PATENT be finally
         rejected, prior to abandonment DOW shall inform NEORX of the art or
         reason for such rejection to

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<PAGE>

         determine whether NEORX has any data or information that may enable
         the rejection to be argued and the PATENT or PROCESS PATENT maintained.

4.2      DOW TO MAINTAIN DEFENSIVE PATENTS - DOW shall also have the obligation
         and be responsible at its own cost and expense for prosecuting and
         MAINTAINING DEFENSIVE PATENTS. DOW shall notify NEORX in writing if DOW
         voluntarily intends to abandon any DEFENSIVE PATENTS and, at NEORX's
         request on a country by country basis made within thirty (30) days
         after receipt of

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<PAGE>

         written notice and status information, DOW shall assign, [*], such
         DEFENSIVE PATENT to NEORX. However, if DOW is abandoning a DEFENSIVE
         PATENT for reasons that are due to lack of inventive step or novelty,
         then DOW shall notify NEORX and may then abandon such DEFENSIVE PATENT.
         After any such assignment of a DEFENSIVE PATENT, DOW may still
         practice, royalty free (I.E., make, use, sell or have sold outside
         NEORX's FIELD, but not sublicense) under the DEFENSIVE PATENT. [*].

4.3      NEORX TO ASSIST DOW IN EXTENSION OR RESTORATION OF PATENTS - Although
         DOW shall be responsible for extension or restoration of PATENTS and
         PROCESS PATENTS, which DOW shall seek under the U.S. Drug Price
         Competition and Patent Term Restoration Act of 1984 and its amendments,
         the Supplementary Certificate of Protection of the Member States of the
         European Union and similar measures in other countries, NEORX agrees to
         provide DOW with reasonably requested records, information and
         assistance to achieve the extension or restoration of any PATENTS or
         PROCESS PATENTS in a country of the TERRITORY.

4.4      NOTICE OF PATENT ACTIVITY - Using good faith efforts, DOW shall
         promptly advise NEORX by sending a revised APPENDIX A OR B, as the case
         may be, of the lapse, nullification, revocation, surrender or
         invalidation of any of the PATENTS, PROCESS PATENTS or DEFENSIVE
         PATENTS. Notification shall be promptly provided quarterly for PATENTS
         AND PROCESS PATENTS that have granted, for any country in the TERRITORY
         where filing for APPROVAL has occurred.

4.5      PATENTS AND PROCESS PATENTS FILE INSPECTION - At a mutually agreed upon
         time, but no more frequently than once per calendar year if there is no
         suit for litigation pending, NEORX may inspect any PATENTS' or PROCESS
         PATENTS' file at the site where the file is kept. Such inspection shall
         be confined to only those files that are not otherwise publicly
         available at the time of such inspection.

4.6      VALIDITY, NON-INFRINGEMENT -

         4.6.1    DOW DOES NOT WARRANT that the manufacture, use and sale of the
                  AGENT or PRODUCT do not fall within the scope of THIRD PARTY
                  patents or the

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<PAGE>

                  industrial property rights of a THIRD PARTY. However, to the
                  best of DOW's knowledge, information and belief, as of the
                  EFFECTIVE DATE, the manufacture, use and sale of the AGENT
                  or PRODUCT for NEORX's FIELD does not fall within the scope
                  of patents which are not owned or licensed by DOW.

         4.6.2    DOW represents that, under the terms of DOW's agreement with
                  the [*], the [*] has granted its entire right, title
                  and interest in, to and under the invention described and
                  claimed in PATENTS to DOW and that the [*] has not made
                  any reservations or contingencies in connection with such
                  grant which may diminish the rights granted by DOW to NEORX
                  under this LICENSE. DOW shall use its good faith efforts to
                  fulfill it's obligations, including payment of royalties,
                  under its agreement with the [*] to avoid being in breach
                  thereof, at least for as long as this LICENSE remains in
                  effect.

4.7      DISCLAIMER OF WARRANTIES AS TO PATENTS AND PROCESS PATENTS - Other than
         as stated in Article 4.6, DOW makes no representation that the
         inventions covered in any PATENTS or PROCESS PATENTS, are patentable or
         that the PATENTS or PROCESS PATENTS are or will be valid or
         enforceable, nor does DOW warrant or represent that the exercise of the
         rights licensed hereunder is free of infringement of patent rights of
         THIRD PARTIES. Should any infringement or damages be alleged, suit
         brought or damages collected therefore, no damages are permitted to be
         collected from DOW, except to the extent DOW breached its
         representations in Article 4.6.

4.8      HOLD HARMLESS - DOW agrees to hold NEORX, its AFFILIATES, and upon
         written notice its sublicensees, harmless for patent infringement under
         any patents, owned by or licensed to DOW which may be otherwise
         infringed by the performance by NEORX, its AFFILIATES and sublicensees
         under this LICENSE so long as this LICENSE is in effect. This hold
         harmless right by DOW does NOT apply to DEFENSIVE PATENTS.

4.9      COOPERATION - NEORX and DOW shall use good faith efforts to cooperate
         with each other with respect to any issues that concern the development
         of the PRODUCT under this LICENSE. NEORX is aware that competition in
         the TERRITORY is likely if no PATENTS exist or are obtained and NEORX
         accepts this LICENSE with that knowledge.

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                       ARTICLE 5 - PAYMENTS AND ROYALTIES

5.1      INITIAL PAYMENT - Within thirty (30) days from SIGNATURE DATE, a
         payment of [*] shall be due to DOW. This [*].

5.2      PAYMENTS ON APPROVALS -

         5.2.1    NEORX shall pay DOW within ten (10) business days payments of:

                  (a)      [*] on the first APPROVAL in the United States for
                           the first indication for cancer therapy in NEORX's
                           FIELD, whether or not such indication is for an
                           ORPHAN DRUG, and

                  (b)      an additional [*] on the first APPROVAL in the United
                           States for the first indication outside of cancer but
                           within NEORX's FIELD.

         5.2.2    Also NEORX shall pay DOW within ten (10) business days
                  payments of:

                  (a)      [*] on the first APPROVAL in EUROPE (I.E.,
                           consolidated submission approved or APPROVAL in any
                           country of EUROPE) for the first indication for
                           cancer therapy in NEORX's FIELD, and

                  (b)      an additional [*] on the first APPROVAL in EUROPE
                           (I.E., consolidated submission approved or APPROVAL
                           in any country of EUROPE) for the first indication
                           outside of cancer but within NEORX's FIELD.

         Should uses for AGENT or PRODUCT other than those defined in NEORX's
         FIELD arise, they shall be subject to negotiation either under a
         separate agreement or by amendment of this LICENSE.

5.3      EARNED ROYALTIES -

         5.3.1    PATENTS - With respect to PRODUCTS and AGENTS which are
                  manufactured, sold or intended to be used in a country in the
                  TERRITORY where such activity would infringe (but for the
                  existence of this LICENSE) a VALID CLAIM of one or more of the
                  PATENTS and except as otherwise

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<PAGE>

                  provided in this Article 5.3 or Article 8.3, 8.4 or 8.5,
                  NEORX will pay DOW an earned royalty of [*] of annual NET
                  SALES of such PRODUCT, on the first [*] of NET SALES
                  achieved by NEORX during NEORX's fiscal year; and [*] of
                  annual NET SALES on any PRODUCT in [*] of NET SALES
                  during NEORX's fiscal year. However, in the event there
                  is COMPETITION in the country in the TERRITORY, then the
                  foregoing royalty rates shall be reduced to [*] of annual NET
                  SALES in such country except for the United States where the
                  royalty rates shall be reduced to [*] of annual NET SALES as
                  long as U.S. Patent [*] is in force and thereafter is reduced
                  to [*] of annual NET SALES. Further, the NET SALES as to which
                  royalties are payable at the rates specified in the preceding
                  sentence and Articles 5.3.2, 8.3 and 8.4 shall not be included
                  in the calculation of cumulative NET SALES for purposes of
                  calculating the [*] cumulative annual NET SALES point at which
                  the [*] royalty increases to [*] above. APPENDIX C sets forth
                  an example of the royalty payment structure as a chart and
                  royalty example calculation, both for reference purposes only.

         5.3.2    PROCESS PATENTS - With respect to PRODUCTS and AGENTS
                  incorporating [*] made by NEORX in the TERRITORY which are
                  manufactured, sold or intended to be used in a country in the
                  TERRITORY where such activity would infringe (but for the
                  existence of this LICENSE) a VALID CLAIM of one or more of the
                  PROCESS PATENTS (but not any PATENTS) and except as otherwise
                  provided in Articles 8.3, 8.4 and 8.5, NEORX will pay DOW an
                  earned royalty of [*] of annual NET SALES of such PRODUCT or
                  AGENT. No royalty is due under this Article 5.3.2 with respect
                  to any NET SALES as to which a royalty is due under Article
                  5.3.1. If DOW supplies the AGENT or [*], then no royalty, if
                  any, shall be due under this Article 5.3.2 because the royalty
                  will be part of the purchase price.

         5.3.3    COMBINATION PRODUCT - NET SALES for a COMBINATION PRODUCT
                  shall be calculated by multiplying the NET SALES of the
                  COMBINATION PRODUCT by the fraction A/(A+B), where A is the
                  gross selling price of the PRODUCT or AGENT sold separately
                  (I.E., without the other components) and B is the gross
                  selling price of the other components. In the event that no
                  such separate sales are made, NET

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                  SALES for royalty payments shall be calculated by multiplying
                  NET SALES of the COMBINATION PRODUCT by the fraction C/(C+D),
                  where C is the fully allocated cost of the PRODUCT or AGENT
                  (not including the other components) and D is the fully
                  allocated cost of such other components, such costs being
                  determined using generally accepted accounting principles
                  consistently applied.

         5.3.4    PUBLISHED PATENT APPLICATIONS - It is recognized that
                  royalties are not paid with respect to pending patent
                  applications included in PATENTS. However, with respect to any
                  country in the TERRITORY that publishes such patent
                  applications, back royalties will be paid by NEORX with
                  respect to NET SALES that have not been subject to royalties
                  under this Article 5 and that occurred in the country prior to
                  patent issuance and after publication in the country of the
                  patent application (E.G., as shown in APPENDICES A and B) that
                  eventually issues as a patent if such NET SALES of the PRODUCT
                  or AGENT would have infringed (but for the existence of this
                  LICENSE) a VALID CLAIM that eventually issues in the patent
                  and that survives any opposition, interference or similar
                  action challenging the issuance, such payment of back
                  royalties to be made after the patent issues and the
                  expiration or conclusion of any opposition, interference or
                  periods for filing in opposition or provoking or declaring an
                  interference and to include interest at the rate specified in
                  Article 5.12 from the date the royalty would have been paid
                  hereunder had such VALID CLAIM been issued at the time of
                  publication of the patent application in the country. For
                  purposes of this Article 5.3.4, publication of a patent
                  application by the European Patent Office shall be deemed
                  publication in all countries that are members of the European
                  Patent Convention.

         5.3.5    EXPIRATION - In no event shall royalties be due under this
                  Article 5.3 after the last to expire PATENT or PROCESS PATENT
                  or AND after any patent term restoration or extension term
                  ceases for a PATENT or PROCESS PATENT or if a VALID CLAIM in a
                  PATENT or PROCESS PATENT does not exist which is being used
                  for PRODUCT or AGENT in any manner by NEORX or its AFFILIATES
                  or sublicensees.

5.4      ACHIEVEMENT OF MILESTONE PAYMENTS - Milestone payments shall be based
         on NET SALES as a total for all uses in NEORX's FIELD and solely on the
         first occurrence of the event as follows:

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<PAGE>

             ------------------------------- --------------------------------
              NET SALES IN A CALENDAR YEAR           PAYMENT DUE DOW
                     US$ (million)                         US$
             ------------------------------- --------------------------------
                          [*]                              [*]
             ------------------------------- --------------------------------
             ------------------------------- --------------------------------
                          [*]                              [*]
             ------------------------------- --------------------------------
             ------------------------------- --------------------------------
                          [*]                              [*]
             ------------------------------- --------------------------------

         with [*] of the payment due within thirty (30) days of the end of the
         fourth quarter of the event for [*] years. The total payment, which
         could be due if all milestones are achieved, is [*]. If the NET SALES
         in subsequent year(s) fall below the trigger NET SALES, the remaining
         payments for the year it did exceed are still due.

5.5      MINIMUM ANNUAL FEES - In the first full calendar year after the first
         APPROVAL for any use in NEORX's FIELD, the following minimum fee shall
         be due to DOW, which may be paid as earned royalty and/or cash:

             ---------------------------------- ------------------------
                    YEAR AFTER APPROVAL                   US$
             ---------------------------------- ------------------------
                            [*]                           [*]
             ---------------------------------- ------------------------
             ---------------------------------- ------------------------
                            [*]                           [*]
             ---------------------------------- ------------------------

         Minimum annual fees are due at the same time as any fourth quarter
         earned royalty payments and earned royalties are creditable against
         these minimum annual fees.

         If the market size is found to be commercially too small for the
         PRODUCT for NEORX's FIELD (E.G., an ORPHAN DRUG) such that NEORX
         believes that it cannot have sufficient profit, then NEORX must show
         DOW the basis for that conclusion together with any reasonably
         requested figures for support of that decision. If DOW agrees with
         NEORX, then NEORX may (a) terminate the LICENSE, (b) request the wavier
         of these minimum fees so that NEORX can sell the PRODUCT for ethical
         concerns or compassionate use in NEORX's FIELD,

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<PAGE>

         but the earned royalty would still be due DOW, or (c) request that
         the Parties agree to discuss the market potential for PRODUCT and
         negotiate in good faith possible amendments to this LICENSE.

5.6      PAYMENTS - A report, including: the amount of payment with the date the
         payment was made; an itemized payment listing; and date of this LICENSE
         under which payment is being made and the number ______ (supplied
         later), shall be sent to:

                  The Dow Chemical Company
                  Royalty Accounting
                  2020 Dow Center
                  Midland, MI 48674
                  USA

         with the check payment made to THE DOW CHEMICAL COMPANY and sent to:

                  Royalty Accounting
                  P.O. Box 92718
                  Chicago, IL 60675-2718
                  USA;

                  or

                  if payment is by wire transfer, then to THE DOW CHEMICAL
                  COMPANY and sent to:

                  [*]
                  New York, NY
                  USA
                  ABA [*]
                  Account [*]
                  For the account of The Dow Chemical Company
                  Reference:  Royalty Payment

         NEORX may arrange that any payments due under this LICENSE may be paid,
         in whole or in part, by NEORX's sublicensee(s); provided, however, that
         NEORX

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                                        20

<PAGE>

         shall still be responsible for any non-payments hereunder and pay
         DOW what is due within 90 days of the original due date.

5.7      [*] ROYALTIES - DOW shall pay any royalties due to [*];
         therefore a further copy of the royalty report and amount paid shall be
         supplied to DOW under Article 15.1. Where necessary for DOW to
         discharge its obligations to [*] under this Article 5.7, concerning
         the PATENTS or TECHNOLOGY under agreements made by DOW, NEORX will
         report reasonable additional information, if needed, for DOW to fulfill
         its obligations. All such information to [*] shall be subject to
         obligations of confidentiality and non-disclosure.

5.8      QUARTERLY ROYALTY REPORTS AND PAYMENTS - Within sixty (60) days after
         the close of each calendar quarter, NEORX shall submit a report on the
         NET SALES of PRODUCT or AGENT in NEORX's FIELD for the TERRITORY in
         sufficient detail to enable a calculation of the royalty due in accord
         with Article 5 and payment of the royalty (if any) due. NEORX will
         indicate if any sales of PRODUCT or AGENT are not covered by PATENTS,
         or PROCESS PATENTS and not royalty-bearing under this Article 5.

         Under Article 4.4, DOW shall provide notice of grant or publication of
         PATENTS or PROCESS PATENTS. The Parties recognize that delays may occur
         in this reporting by DOW and NEORX shall not be held liable under
         Article 5.3.4 for back due royalties (I.E., for this purpose - due more
         than one quarter prior to the current reporting period) caused by late
         notification by DOW for such recently granted or published PATENTS or
         PROCESS PATENTS.

5.9      BOOKS OF ACCOUNT - NEORX shall maintain true and complete books of
         account containing an accurate record of all data necessary for the
         proper computation of royalty payments due from it or on behalf of any
         AFFILIATE. Such records shall be maintained for at least [*] after the
         date of the pertinent royalty payment.

5.10     AUDIT RIGHT - DOW shall have the right through a firm of independent
         public accountants, to whom NEORX has no reasonable objection, to
         examine the books of account of NEORX at reasonable times within three
         (3) years after the end of the calendar year to which they relate (but
         not more than once in each calendar year) for the purpose of verifying
         the correctness of any report concerning diligence or payment of
         royalties under Articles 3 and 5, respectively. Such

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<PAGE>


         examination shall be made during normal business hours at the place
         of business of NEORX. The information furnished, as a result of any
         such examination shall be maintained in confidence on the terms
         specified in Article 6. The fees and expenses of such an audit shall
         be borne by DOW. If any such audit shows any underpayment, a
         correcting payment shall be made within thirty (30) days of NEORX's
         receipt of the auditors' statement, unless NEORX disputes the
         auditors' statement. If such error is material (meaning more than [*]),
         then if NEORX owes DOW from such material error, NEORX shall be
         subject to a penalty as if the payment were deemed late in accord
         with Article 5.12. Should NEORX fail to make any correcting payment
         within sixty (60) days from receipt of the auditors' statement, then
         DOW shall have the right to terminate this LICENSE under Article
         12.5, unless in good faith NEORX disputes the auditors' statement in
         which event Article 16 applies.

5.11     WITHHOLDING TAX PAYMENTS - If any taxes for DOW's account, withholding
         or otherwise, are levied by any taxing authority in the TERRITORY in
         connection with the receipt by DOW of any amounts payable under Article
         5 of this LICENSE according to any tax treaty or agreement between the
         United States and any country in the TERRITORY, then NEORX shall have
         the right to pay such taxes to the local tax authorities and to pay to
         DOW the net amount due after reduction by the amount of such taxes,
         together with

                  (i)      evidence of payment of such taxes and a translation
                           thereof into English, and

                  (ii)     indication of the amount of such tax paid, and

                  (iii)    indication of the country in the TERRITORY and the
                           authority to whom it was paid, and

                  (iv)     comply with NEORX's royalty reporting obligations
                           under this LICENSE.

         However, if DOW still requires further information, the report due
         under Article 5.11 may also be requested by DOW and NEORX shall
         promptly provide that information.

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<PAGE>

5.12     LATE PAYMENTS - Royalty payments not remitted or deposited by the due
         date shall bear interest at the current prime rate [*] established by a
         leading New York bank, such as CitiBank, as published in THE WALL
         STREET JOURNAL. Should NEORX fail to make any late payment within sixty
         (60) days from its due date, then DOW shall have the right to terminate
         this LICENSE under Article 12.5 upon fifteen (15) days written notice
         to NEORX to allow cure.


                           ARTICLE 6 - CONFIDENTIALITY

6.1      NONDISCLOSURE - Each Party shall use good faith efforts to retain in
         confidence and not disclose to any third party each other's
         CONFIDENTIAL INFORMATION (which includes, but is not limited to,
         TECHNOLOGY, PATENTS, and any samples of [*], AGENT or PRODUCT)
         disclosed pursuant to the terms of this LICENSE. Such "good faith
         efforts" shall mean the same degree of care, but no less than a
         reasonable degree of care, as the receiving Party uses to protect its
         own CONFIDENTIAL INFORMATION of a like nature. NEORX shall continue to
         use the same good faith efforts with respect to the TECHNOLOGY and any
         samples of [*], AGENT and PRODUCT already in its possession under the
         OPTION that it received directly or indirectly from DOW.

6.2      EXCEPTIONS - Excepted from the obligation of confidence under Article
         6.1 is that information which:

                  (a)      is available, or becomes available, to the general
                           public without fault of the receiving Party; or

                  (b)      is obtained by the receiving Party without an
                           obligation of confidence from a THIRD PARTY (other
                           than a governmental agency, the FDA, REGULATORY
                           AUTHORITIES or [*]) who is rightfully in
                           possession of such information and is under no
                           obligation of confidentiality to the disclosing Party
                           concerning such information; or

                  (c)      is required by law or by court order to be disclosed
                           by the receiving Party in which cases the receiving
                           Party will use its best efforts to limit such
                           disclosure to that required by law and to maintain
                           the confidentiality of the disclosed information to
                           the extent possible; or

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<PAGE>

                  (d)      must be necessarily disclosed to REGULATORY
                           AUTHORITIES to permit NEORX to sell PRODUCT or AGENT
                           in NEORX's FIELD; or

                  (e)      is released from confidentiality in writing by the
                           disclosing Party.

         For the purpose of Article 6.1, a specific item of TECHNOLOGY shall not
         be deemed to be within the foregoing exceptions merely because it is
         embraced by more general information in the public domain or in the
         possession of the receiving Party. In addition, any combination of
         features shall not be deemed to be within the foregoing exceptions
         merely because individual features are in the public domain or in the
         possession of the receiving Party, but only if the combination itself
         and its principle of operation are in the public domain or in the
         possession of the receiving Party.

6.3      LEGALLY REQUIRED DISCLOSURES - Notwithstanding the provisions of
         Article 6.1, if the receiving Party becomes legally compelled to
         disclose any of the disclosing Party's CONFIDENTIAL INFORMATION, the
         receiving Party shall promptly advise the disclosing Party of such
         required disclosure in order that the disclosing Party may seek a
         protective order or such other remedy as the disclosing Party may
         consider appropriate in the circumstances. The receiving Party shall
         disclose only that portion of the CONFIDENTIAL INFORMATION, which it is
         legally required to disclose. Such a disclosure shall not release the
         receiving Party with respect to the CONFIDENTIAL INFORMATION so
         disclosed except to the extent of permitting the required disclosure.

6.4      DISCLOSURE TO AFFILIATES, CONTRACTORS - NEORX may disclose TECHNOLOGY
         to its AFFILIATES, sublicensees, consultants, its clinical
         investigators and contractors (E.G., parties under contract with NEORX
         or its AFFILIATES for the custom manufacturing or shipping of PRODUCT,
         conduct of clinical studies or obtention of registration in the
         TERRITORY), as may be necessary to exercise the rights granted
         hereunder and to register and prepare for commercialization of PRODUCT,
         and to commercialize PRODUCT under this LICENSE, under conditions of
         confidentiality at least as stringent as those set out in Articles 6.1,
         6.2 and 6.3.

6.5      DISCLOSURE TO [*] - Notwithstanding the provisions of Article 6.1,
         DOW may disclose the provisions of this LICENSE to [*] to comply
         with DOW's reporting obligation. However, DOW shall request that the
         terms of this LICENSE remain confidential and be on a need-to-know
         basis.

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<PAGE>

6.6      DOCUMENT RETURN - In the event of termination of this LICENSE for any
         reason prior to its normal expiration, each Party will cease its use of
         the other Party's CONFIDENTIAL INFORMATION provided hereunder
         (including TECHNOLOGY that is CONFIDENTIAL INFORMATION) and, on written
         request, within sixty (60) days return all such CONFIDENTIAL
         INFORMATION, including any copies thereof; except that such
         CONFIDENTIAL INFORMATION as is or has become no longer subject to
         confidentiality under Article 6.1 need not be returned or destroyed.
         Notwithstanding the foregoing, a Party may retain such documents as are
         necessary for it to discharge its surviving obligations hereunder and
         its legal obligations to the governmental authorities for counterpart
         agencies to DOE and NRC; and NEORX may retain such copies of documents
         as may be necessary for the defense of product liability or other
         litigation or similar proceedings relating to AGENT or PRODUCT. Each
         Party may retain one copy of any documents in its legal department as a
         record of what was transmitted and to meet any continuing obligations
         under this LICENSE.

6.7      SURVIVAL OF CONFIDENTIALITY - Termination of this LICENSE for any
         reason shall not relieve the Parties of their obligations under Article
         6. The provisions of Article 6 shall survive termination of this
         LICENSE for [*].


                   ARTICLE 7 - THIRD PARTY INFRINGEMENT CLAIMS

7.1      DEFENSE OF THIRD PARTY PATENT CLAIMS - If a claim is brought by a THIRD
         PARTY that manufacture, use or the sale of AGENT or PRODUCT in the
         TERRITORY (regardless of use) infringes a patent of such THIRD PARTY,
         NEORX will give prompt written notice to DOW of such claim if it
         concerns a PATENT or PROCESS PATENT. [*] NEORX at its option and
         expense may participate in any suit resulting from such claim that
         DIRECTLY AFFECTS its market in NEORX's FIELD in the TERRITORY.

7.2      MUTUAL DECISIONS - From the SIGNATURE DATE and using their good faith
         efforts, NEORX and DOW shall discuss any claim or suit brought by a
         THIRD PARTY for patent infringement that such THIRD PARTY's patent is
         infringed by

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<PAGE>

         the manufacture, use or sale of AGENT or PRODUCT by NEORX or its
         AFFILIATES in NEORX's FIELD in the TERRITORY. Specifically, NEORX and
         DOW shall mutually try to agree on the strategy for such suit or
         claim, E.G. whether to negotiate a settlement, sue or withdraw from
         the country in the TERRITORY in which infringement is claimed; the
         basis to be determined for sharing the costs of litigation, damages
         awarded, and royalty to be paid to the third party; which Party
         should conduct the defense or if both NEORX and DOW should jointly
         defend; and the consequences of such decisions, such as amendment to
         this LICENSE with regard to royalties due to DOW.

7.3      THIRD PARTY LICENSE - The Parties shall use their good faith efforts
         (either individually or together) to negotiate any necessary agreement
         for royalty payment to third parties with a view to enabling the
         PRODUCT to be commercialized in NEORX's FIELD in the TERRITORY. As of
         the EFFECTIVE DATE, DOW is not aware of the need for any such third
         party license that is not already obtained.


                    ARTICLE 8 - PATENT ENFORCEMENT LITIGATION

8.1      PROSECUTION BY DOW - DOW, at its sole discretion, may take action on
         its own behalf and expense to institute any action or proceeding by
         reason of infringement of any of the PATENTS and PROCESS PATENTS for
         NEORX's FIELD. If either Party learns of any infringement of a PATENT
         or PROCESS PATENT or misappropriation of trade secrets for PROCESS or
         TECHNOLOGY by a third party, it shall promptly notify the other Party.
         DOW shall have the first right, at its own expense, to prosecute all
         litigation against a third party infringer who may be infringing a
         PATENT or PROCESS PATENT. NEORX shall provide all reasonable
         cooperation, including any necessary use of its name, required to
         prosecute such litigation. NEORX shall be consulted concerning the
         litigation. DOW will bear the costs and shall be entitled to any
         recovery obtained from such litigation, settlement or compromise
         thereof until recovery of all expenses. Any recovery above expenses
         shall be shared with [*] going to DOW and [*] going to NEORX.

8.2      PROSECUTION BY NEORX - If DOW does NOT prosecute such infringer or
         otherwise abate such infringement (which infringement must be of
         commercial significance

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<PAGE>

         to NEORX and if disputed by DOW then Article 16 may be used) within
         ninety (90) days after giving or receiving notification of such
         infringement in the TERRITORY, unless an extension of the term is
         mutually agreed upon by the Parties, then, NEORX shall have the right
         to prosecute such infringer at its own expense in the FIELD in the
         TERRITORY and shall be entitled to retain any recovery obtained from
         such litigation, settlement or compromise thereof. NEORX's cost of
         litigation in any quarter may be credited against up to [*] of the
         royalties due to DOW under Articles 5.3, 5.4, 5.5 and 5.6 in the
         following quarter(s) until fully credited. However, NEORX shall place
         all royalties due to DOW in escrow from the date of filing the suit
         until the action or proceeding is finally concluded whereupon: if the
         PATENT or PROCESS PATENT in the country in the TERRITORY is held
         valid (whether infringed or not), then the royalties in escrow (after
         deduction of NEORX's cost of litigation as referred to hereinabove)
         shall be paid to DOW; or if the PATENT or PROCESS PATENT in the
         country in the TERRITORY is held invalid (whether infringed or not),
         then the royalties in escrow shall be paid to NEORX.

         At NEORX's request, DOW shall cooperate with NEORX in such litigation,
         including joining in said litigation. DOW shall also cooperate, at
         NEORX's expense, by way of providing access to evidence and witnesses
         available to DOW.

8.3      PROSECUTION BY NEITHER NEORX NOR DOW - If DOW decides, after consulting
         with NEORX, that neither DOW nor NEORX will defend the PATENT or
         PROCESS PATENT in the FIELD in the particular country in the TERRITORY,
         then the royalty for that PATENT or PROCESS PATENT in that country
         becomes zero percent (0%) upon that decision date.

8.4      ROYALTY REDUCTION - If there is COMPETITION and NEORX desires that DOW
         enforce PATENTS or PROCESS PATENTS, where such PATENTS or PROCESS
         PATENTS are allegedly infringed in the FIELD in a country of the
         TERRITORY, in accord with Article 8.1, and such infringer
         constitutes[*], then NEORX must provide to DOW, at NEORX's expense, (a)
         evidence in writing of the COMPETITION and percent of loss of NEORX's
         NET SALES to this single infringer, (b) evidence in writing of
         infringement of a PATENT or PROCESS PATENT in the country of the
         TERRITORY, and (c) all reasonable cooperation with DOW, E.G., by
         providing at DOW's request information in NEORX's possession,
         witnesses, any technical assistance, and release to use any evidence of
         such infringement.

         If there is COMPETITION and DOW elects not to enforce the PATENT or
         PROCESS PATENT and does not permit NEORX to enforce the PATENT or

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<PAGE>


         PROCESS PATENT under Article 8.2 in that country of the TERRITORY, then
         NEORX may [*]. If there is COMPETITION and NEORX asks that DOW enforce
         a DEFENSIVE PATENT in a country of the TERRITORY and DOW elects not to
         enforce the DEFENSIVE PATENT, then NEORX may [*]. DOW is permitted six
         (6) months after receipt from NEORX of its request and the accompanying
         evidence to take action to stop the infringement. No royalty reduction
         in this Article 8.4 shall occur in this six-month period.

8.5      INVALIDITY - In the event that a PATENT or PROCESS PATENT in the
         TERRITORY is finally declared invalid or unenforceable in a judicial or
         administrative proceeding from which no appeal is or can be taken, then
         from and after that date no royalties shall be paid on the basis of
         that PATENT or PROCESS PATENT in the relevant country of the TERRITORY,
         subject to the provisions of Article 8.2, provided, however, that
         royalties due for other PATENTS or PROCESS PATENTS, in the TERRITORY
         not so held invalid or unenforceable shall not be affected.

8.6      SETTLEMENT - Any settlement of an infringement suit, whether brought by
         DOW or by NEORX, shall be subject to the consent of both Parties, which
         consent shall not be unreasonably withheld.

8.7      COOPERATION - Each Party shall cooperate with the other Party to the
         extent reasonably requested in any legal action:

                  (i)      brought by a THIRD PARTY against one Party; or

                  (ii)     brought by a THIRD PARTY against both Parties; or

                  (iii)    taken against a THIRD PARTY by either Party

         regarding PATENTS and PROCESS PATENTS in NEORX's FIELD in the
         TERRITORY, and each Party shall have the right to participate in any
         defense, compromise or settlement to the extent that, in its judgment,
         it may be prejudiced thereby. In addition, NEORX shall not settle any
         claim or suit in any manner that shall adversely affect any PATENTS and
         PROCESS PATENTS, require any payment by DOW or reduce the royalty due
         to DOW hereunder without the prior written consent of DOW, except as
         provided in Article 8.2. In addition, DOW

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<PAGE>

         shall not settle any claim or suit in any manner that shall adversely
         affect NEORX's license rights hereunder, require any payment by NEORX.


             ARTICLE 9 - U.S. EXPORT CONTROL AND GOVERNMENT LICENSES

9.1      COMPLIANCE - NEORX agrees to comply with all necessary United States,
         European and other country's governmental regulations in the TERRITORY
         with respect to export of TECHNOLOGY and any PRODUCT or AGENT or [*].
         NEORX agrees to not export or re-export any TECHNOLOGY, PRODUCTS, AGENT
         or [*] received from DOW or the direct products of such TECHNOLOGY to
         any prohibited country listed in the U.S. Export Administration
         Regulations unless properly authorized by the U.S. government. NEORX
         shall be responsible for the acts of its AFFILIATES, contractors,
         consultants and sublicensees. NEORX assumes all liability if it or its
         AFFILIATES fail to obtain any of the necessary licenses or commit any
         violations of the United States Export Laws or Regulations.

9.2      DOE, NRC LICENSES - NEORX agrees to obtain all necessary licenses and
         to comply with all applicable regulations of agencies similar to DOE
         and NRC in the TERRITORY with respect to AGENT and PRODUCT.

9.3      CLEARANCES - NEORX agrees to obtain all necessary clearances from any
         government in the TERRITORY for export or re-export with respect to the
         TECHNOLOGY or AGENT or PRODUCT.


               ARTICLE 10 - PRODUCT LIABILITY AND INDEMNIFICATION;

10.1     INDEMNITY BY DOW - DOW shall indemnify and hold NEORX and its
         AFFILIATES, and their respective agents, directors, officers and
         employees harmless from and against any and all liabilities, claims,
         demands, damages, costs, expenses or money judgments (including
         reasonable attorneys' fees and expenses) incurred by or rendered
         against any of them for personal injury, sickness, disease or death or
         property damage which directly arises out of:

         (a)      the intentional misconduct or negligence of DOW; or

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pursuant to an application for confidential treatment.

                                     29
<PAGE>

         (b)      the breach by DOW of its representations, warranties or
                  covenants contained in this LICENSE; or

         (c)      any activity carried out with AGENT or PRODUCT by DOW other
                  than through or on behalf of NEORX and its AFFILIATES (such as
                  preparation of PRODUCT for the clinical trials at [*]) under
                  this LICENSE or other written agreements between the Parties

         provided, however, that NEORX shall give DOW notice in writing as soon
         as practicable of any such claim or lawsuit and shall permit DOW to
         undertake the defense thereof at DOW's expense. However,

                  (i)      NEORX will cooperate in such defense by providing
                           access to witnesses and evidence available to it.
                           NEORX shall have the right to participate in any
                           defense to the extent that in its judgment, NEORX may
                           be prejudiced thereby; and

                  (ii)     in any claim or suit in which NEORX seeks
                           indemnification by DOW, NEORX shall not settle, offer
                           to settle or admit liability or damages in any such
                           claim or suit without the prior written consent of
                           DOW.

10.2     INDEMNITY BY NEORX - NEORX shall indemnify and hold DOW and its
         AFFILIATES, and their respective agents, directors, officers and
         employees harmless from and against any and all liabilities, claims,
         demands, damages, costs, expenses or money judgments (including
         reasonable attorneys' fees and expenses) incurred by or rendered
         against any of them for personal injury, sickness, disease or death or
         property damage which arises out of

         (i)      the manufacturing, testing, use, promotion, sale or
                  distribution of AGENT or PRODUCT by NEORX or its AFFILIATES,
                  except for those instances provided in Article 10.1 for which
                  DOW is obligated to indemnify NEORX; or

         (ii)     the breach by NEORX of any of its representations, warranties
                  or covenants contained in this LICENSE; or

         (iii)    NEORX performing any function for NEORX's FIELD under the
                  ongoing clinical trials, whether under a DOW clinical trial or
                  not;

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<PAGE>

         provided, however, that DOW shall give NEORX notice in writing as soon
         as practicable of any such claim or lawsuit and shall permit NEORX to
         undertake the defense thereof at NEORX's expense. However,

         (i)      DOW will cooperate in such defense by providing access to
                  witnesses and evidence available to it. DOW shall have the
                  right to participate in any defense to the extent that in its
                  judgment, DOW may be prejudiced thereby; and

         (ii)     in any claim or suit in which DOW seeks indemnification by
                  NEORX, DOW shall not settle, offer to settle or admit
                  liability or damages in any such claim or suit without the
                  prior written consent of NEORX.


                      ARTICLE 11 - WARRANTIES AND INSURANCE

11.1     BELIEF OF ACCURACY - DOW represents that the TECHNOLOGY, PROCESS and
         any other CONFIDENTIAL INFORMATION transferred or provided to NEORX
         hereunder are believed to be accurate and complete as of their current
         status at DOW at the EFFECTIVE DATE and that DOW's interpretations and
         conclusions drawn therefrom were made in good faith and in the exercise
         of DOW's scientific judgment as of the dates of the documents contained
         therein, and that to the best of DOW's knowledge, data subject to
         regulations regarding GMPs (Good Laboratory Practices and Good Clinical
         Practices) and other FDA regulations, is in compliance with such
         regulations. However, DOW does not warrant or represent that such
         information is or will be sufficient to obtain APPROVAL to market
         PRODUCT or to commercially produce AGENT or PRODUCT or to commercialize
         AGENT or PRODUCT with REGULATORY AUTHORITIES in the TERRITORY. NEORX
         represents that it will be solely relying on its own evaluation of the
         TECHNOLOGY and the other CONFIDENTIAL INFORMATION transferred or
         provided to it hereunder and on its own medical and scientific
         expertise in using the same in its development and commercialization of
         AGENT and PRODUCT.

11.2     AUTHORITY - Each Party represents and warrants to the other Party that
         it has full power and authority to enter into this LICENSE.

         DOW represents and warrants to NEORX that it has full power and
         authority to grant the licenses granted in Article 2

                                     31
<PAGE>

11.3     INSURANCE - NEORX agrees to carry such liability insurance as would
         reasonably be expected of a company of NEORX' net worth operating in
         the pharmaceutical industry for the commercial purpose of PRODUCT under
         this LICENSE and sufficient to meet any governmental requirements.
         Written assurance that such insurance is in effect must be provided to
         DOW by the SIGNATURE DATE. NEORX agrees to maintain such insurance for
         the term of this LICENSE.

11.4     ADDITIONAL WARRANTIES BY DOW - DOW represents and warrants to NEORX
         that:

         (a)      as of the EFFECTIVE DATE, APPENDIX A AND B, contain a true and
                  complete listing of all patents and patent applications in the
                  TERRITORY that are owned by DOW with any claims covering an
                  AGENT or PRODUCT, use or manufacture of an AGENT or PRODUCT in
                  NEORX's FIELD or a process to make [*]; and

         (b)      DOW has not licensed, [*].

11.5     GENERIC PRODUCTS - DOW warrants and covenants that: [*].


                        ARTICLE 12 - TERM AND TERMINATION

12.1     TERM - Unless terminated under the provisions of this Article 12, this
         LICENSE shall continue in effect until the expiration of ALL PATENTS
         and PROCESS PATENTS, provided, however, that the Articles of Article
         12.7 shall survive termination of this LICENSE.

         When this LICENSE expires under this Article 12.1, the licenses granted
         under this LICENSE shall be paid-up; however, any payments still due
         under Article 5.4 will continue until paid in full. However, NEORX may
         continue to practice the TECHNOLOGY.

12.2     FAILURE TO USE LICENSE - If NEORX and its AFFILIATES shall have

         (i)      discontinued selling AGENT or PRODUCT in commercial quantities
                  using their reasonable and diligent efforts in accord with
                  Article 3.1 to commercialize; or

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<PAGE>

         (ii)     not paid the minimum annual fees required under Article 5.6,

         then either NEORX or DOW shall have the right to terminate this LICENSE
         upon [*]' written notice, unless during such [*] period after notice
         the failure described in (i) through (iii) has been remedied or cured
         (E.G., through the recommencing of commercial sales or the payment of
         the minimum annual fee). If termination under this Article 12.2 results
         voluntarily, then NEORX shall promptly supply to DOW all registration
         information for REGULATORY AUTHORITIES that is available to NEORX or
         its AFFILIATES for use by DOW, its AFFILIATES or sublicensees for a
         fair consideration to NEORX.

12.3     TERMINATION FOR MATERIAL BREACH - In the event of a material breach by
         either DOW or NEORX of any of the obligations contained in this
         LICENSE, the other Party shall be entitled to terminate this LICENSE by
         notice in writing under Article 15.1 provided that such notice shall
         specify the breach or breaches complained of. If the said breach or
         breaches are capable of remedy, the Party committing such breach or
         breaches shall be entitled to a period of [*] days from the delivery of
         such notice in which to remedy or to undertake to remedy the same. In
         the case the defaulting Party shall fail to remedy the breach or to
         undertake to remedy the breach to the satisfaction of the injured
         Party, the injured Party shall have the right to terminate this LICENSE
         in whole or only terminate those rights and obligations relating to the
         particular breach by simple notification to the Party in default.
         Failure of a Party to exercise its rights under this Article 12.3 shall
         not be construed as a waiver as to future breaches whether or not they
         are similar. Sales of PRODUCT or AGENT outside the TERRITORY or FIELD
         (E.G., including off label uses), where such sales are intentional on
         the part of NEORX, its AFFILIATES or sublicensees, shall constitute a
         material breach if such AGENT, PRODUCT, process for manufacture, or use
         falls within the scope of any unexpired DOW patent.

12.4     TERMINATION BY NEORX - NEORX may surrender and terminate this LICENSE
         on [*]' written notice to DOW. NEORX will disclose to DOW its reasons
         for any such termination.

12.5     TERMINATION BY DOW - DOW shall have the further right to terminate this
         LICENSE immediately on written notice to NEORX if:

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pursuant to an application for confidential treatment.

                                     33

<PAGE>

         (a)      NEORX shall cease to carry on business or shall go into
                  liquidation or a receiver shall be appointed to NEORX's
                  assets; or

         (b)      NEORX shall become bankrupt or insolvent or unable to meet any
                  of its financial obligations on their due dates; or

         (c)      NEORX fails to meet any of its payments in accord with
                  Articles 5.10 or 5.12, unless a good faith dispute exists in
                  which event Article 16 applies.

12.6     ON TERMINATION - NEORX shall, upon termination of this LICENSE by DOW
         under Article 12.2, 12.3 or 12.5 or termination by NEORX under Article
         12.2, 12.3 or 12.4:

         (a)      return to DOW all copies of documents containing TECHNOLOGY
                  and any materials received from DOW under confidentiality and
                  DOW's CONFIDENTIAL INFORMATION concerning AGENT and PRODUCT in
                  NEORX's FIELD as set forth in Article 6.6; and

         (b)      pay to DOW all payments and royalties due or accrued at the
                  termination date within thirty (30) days after termination,
                  AND pay to DOW when due all payments due under Article 5.4,
                  but if termination occurs under Article 12.3 (if breach by
                  NEORX) or 12.5, then payments due under Article 5.4, if
                  applicable, shall be accelerated and due within said thirty
                  (30) days; and

         (c)      make no further use of any kind of any and all TECHNOLOGY
                  disclosed hereunder by DOW, except to the extent such
                  information has become public knowledge other than through
                  fault of NEORX, and make no further use of the surviving
                  PATENTS; and

         (d)      assign to DOW any distributorships, AGENT or PRODUCT
                  manufacturing agreements and sublicense agreements, to the
                  extent they are specific to the AGENT or PRODUCT and are
                  assignable and to the extent such agreements were previously
                  agreed by the Parties to survive termination of this LICENSE;
                  or, at DOW's option, terminate such agreements as are
                  terminable unilaterally by NEORX.

12.7     SURVIVAL OF CERTAIN OBLIGATIONS - On termination or expiration of this
         LICENSE: (a) the obligations of confidentiality set forth in Article 6
         shall survive for the time stated therein; (b) export control
         compliance set forth in Article 9 shall survive; (c) the
         indemnification obligations set forth in Article 10 shall also survive
         as to all claims or actions arising from events which occurred before
         termination; and (d) on expiration of this LICENSE, TECHNOLOGY shall be
         paid-up and rights to its

                                        34

<PAGE>

         use by NEORX shall continue. Upon termination of this LICENSE by DOW
         for any reason pursuant to this Article 12, any sublicensee of NEORX
         who is not then in material breach shall have its sublicense
         converted to a direct license from DOW under the terms and conditions
         of this LICENSE, as further limited and restricted by the terms of
         the original sublicense.

12.8     SALE OF PRODUCT AFTER TERMINATION - In the event of termination of this
         LICENSE, NEORX and its AFFILIATES and sublicensees (who have been
         identified in writing to DOW) have the right over the following six (6)
         months solely to sell any inventory of PRODUCTS (including PRODUCTS
         manufactured from materials on hand or on order under an agreement)
         provided earned royalties under Articles 5.3 and 5.5 and milestone
         payments under Article 5.4 are paid thereon to DOW as would otherwise
         be due and payable during the term of this LICENSE. DOW shall have the
         right, but not the obligation, to purchase any PRODUCT, AGENT,
         ADDITIONAL AGENT, or [*] not committed by agreement at [*].



                           ARTICLE 13 - FORCE MAJEURE

13.1     EVENT OF FORCE MAJEURE - In the event that performance under this
         LICENSE, or any obligation hereunder, is hindered, delayed or prevented
         by reason of: acts of God; strikes; lockouts; labor troubles;
         intervention or any action or inaction of any government authority; any
         material change in any regulations, policies or procedures of any
         government authority; fire; riots; insurrections; invasions; war; or
         other reason of similar nature beyond the reasonable control of the
         Party and are without its fault or negligence, then performance of that
         act shall be excused for the period of the delay and the period for the
         performance of that act shall be extended for an equivalent period.

13.2     NOTIFICATION - Upon occurrence of an event of force majeure, the
         affected Party shall promptly notify the other Party in writing,
         setting forth the nature of the occurrence, its expected duration and
         how that Party's performance is affected. The affected Party shall
         resume the performance of its obligations as soon as practicable after
         the force majeure event ceases.

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<PAGE>

                              ARTICLE 14 - CONSENTS

14.1     COMMITMENTS - DOW agrees to take reasonable efforts to maintain in full
         force and effect the agreements or written commitments, which DOW has
         made prior to the SIGNATURE DATE for AGENT or PRODUCT in NEORX's FIELD
         in the TERRITORY.

14.2     AGREEMENTS - DOW expects to enter into other agreements for a licensee
         for AGENT and PRODUCT in NEORX's FIELD OUTSIDE the TERRITORY, I.E.,
         Australia. After the SIGNATURE DATE, NEORX consents to let DOW disclose
         to this other DOW licensee that NEORX is DOW's licensee for the
         TERRITORY. If desired by NEORX and acceptable to that DOW licensee, DOW
         shall provide NEORX with information on whom to contact at that DOW
         licensee for possible collaboration between NEORX and such DOW licensee
         in NEORX's FIELD.



                              ARTICLE 15 - NOTICES

15.1     OFFICIAL - Any notice, request or communication specifically provided
         for or permitted to be given under this LICENSE must be in writing and
         may be delivered by hand delivery, courier service, or electronic
         transmission such as telex, facsimile, telegram or electronic mail, and
         shall be deemed effective as of the time of actual delivery thereof to
         the addressee. For purposes of notice the addresses of the Parties0
         shall be as follows:

                  DOW:              The Dow Chemical Company
                                    Patent Department
                                    1790 Building, Washington Street
                                    Midland, Michigan  48674
                                    Attention:  Karen L. Kimble, JD
                                    Senior Counsel
                                    Telephone: 517-636-1687
                                    Facsimile: 517 - 636 - 2523

                  NEORX:            NeoRx Corporation
                                    410 West Harrison
                                    Seattle, Washington 98119
                                    Attention:  Paul G. Abrams, MD, JD
                                    Chief Executive Officer

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<PAGE>

                                    Telephone: 206-281-7001, ext. 521
                                    Facsimile:  206-284-7112

                  with a copy to:

                                    NeoRx Corporation
                                    410 West Harrison
                                    Seattle, Washington 98119
                                    Attention:  Anna Lewak Wight, JD
                                    Director of Intellectual Property
                                    Telephone: 206-7001, ext. 526
                                    Facsimile:  206-286-2537

15.2     TRANSITION - For purposes of scientific reporting, the addresses of the
         Parties shall be as follows:

                  DOW:              The Dow Chemical Company
                                    Building B-1222
                                    2301 Brazosport Blvd.
                                    Freeport, Texas 77541
                                    Attention:  Jim Simon, PhD
                                    Senior Associate Scientist
                                    Telephone:  409-238-7494
                                    Facsimile: 409-238-0516

                  NEORX:            NeoRx Corporation
                                    410 West Harrison
                                    Seattle, Washington 98119
                                    Attention:  Alan R. Fritzberg, PhD
                                    Chief Scientist and
                                    Chairman of the Scientific Board
                                    Telephone:  206-286-2522
                                    Facsimile:  206-284-7112

15.3     CHANGES - Each Party may change its address and its representative for
         notice by the giving of notice thereof in the manner hereinabove
         provided.

                                        37

<PAGE>

                         ARTICLE 16 - DISPUTE RESOLUTION

16.1     CHOICE OF LAW - This LICENSE shall be governed by the laws of the State
         of Delaware, except its conflict of laws principles, in all respects of
         validity, construction and performance, except that all questions
         concerning the construction, validity, coverage or infringement of
         patents or PATENTS, PROCESS PATENTS, and DEFENSIVE PATENTS shall be
         decided in accordance with the patent law of the country where the
         patent was granted.

16.2     DISPUTES - Both Parties shall make good faith efforts to resolve any
         questions concerning construction and performance under this LICENSE,
         excluding PATENTS, PROCESS PATENTS, and DEFENSIVE PATENTS, by:

         16.2.1   Notice, contact and negotiation, all proceedings and documents
                  in English, between the Parties listed under Article 15.1
                  within [*] from the date of the notice by negotiation either
                  by telephone or by meeting in Chicago, IL; and

                  If unsuccessful under Article 16.2.1, then senior executive
                  management with settlement authority and counsel of DOW and
                  NEORx shall meet at a mutually agreeable location within [*]
                  from a date of notice that Article 16.2.1 failed to resolve
                  the issues. Counsel shall present the legal and factual
                  arguments to such executives in English, with supporting
                  evidence if necessary, and resolution by these executives is
                  expected within ten (10) days, which may be reduced to writing
                  in English as an amendment to this LICENSE; and

                  If such executives have not met or resolved the issues under
                  Article 16.2.2, then within [*] from the date of the notice
                  under Article 16.2.1, the Parties shall submit the issues to
                  mediation in Chicago, IL, in English, in accordance with the
                  Rules of the American Arbitration Association ("AAA"), which
                  may be modified by the Parties, and judgment shall not be
                  binding. The Parties agree that the following procedures shall
                  be adhered to even though they may, in part, not be in full
                  conformance with said Rules:

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<PAGE>

                  (a)      One mediator shall be selected within [*] from a list
                           of at least 20 mediators selected by the AAA composed
                           of counsel with chemistry or pharmaceutical expertise
                           who are practicing or retired partners in law firms
                           or in-house corporate counsel not affiliated with the
                           Parties with at least 15 years of experience in law
                           and knowledge of the pertinent laws of any country
                           relevant to the dispute. The mediation proceedings
                           and reports shall be in English. The time from the
                           beginning of submission for mediation and conclusion
                           of any oral or written proceedings shall not exceed
                           six (6) months; and

                  (b)      Discovery shall be limited to only that for which
                           each Party has a substantial, demonstrable need, and
                           shall be conducted in the most expeditious and
                           cost-effective manner. The mediator shall resolve any
                           issues with regard to the discovery. Decision by the
                           mediator shall be given in writing within thirty (30)
                           days from the end of oral proceedings; and

                  (c)      Although the decision by the mediator is non-binding,
                           should either Party then litigate in a court of
                           competent jurisdiction for the Parties, either Party
                           may introduce into court the decision reached by
                           mediation with its supporting evidence.



                             ARTICLE 17 - ASSIGNMENT

17.1     ASSIGNMENT - Neither Party to this LICENSE shall assign any rights
         hereunder without the prior written consent of the other Party, such
         consent not to be unreasonably withheld. The Parties agree, however,
         that without such consent being required from DOW, NEORX may assign to
         its AFFILIATES, but DOW must be notified in writing in accord with
         Article 15.1.

17.2     CONSOLIDATION, REORGANIZATION OR MERGER - Should NEORX be consolidated,
         reorganized or merged with another entity, this LICENSE and all rights
         and obligations arising under this LICENSE may be assigned to the
         successor entity or the assignee of all or substantially all of NEORX's
         business and assets related to AGENT or PRODUCT without DOW's prior
         written consent. However NEORX shall promptly notify DOW prior to such
         action in accord with Article 15.1.

17.3     EFFECT ON SUCCESSORS AND ASSIGNEES - This LICENSE shall inure to the
         benefit of and be binding upon such successors and permitted assignees.

                                        39

<PAGE>

                      ARTICLE 18 - MISCELLANEOUS PROVISIONS

18.1     AMENDMENTS - This LICENSE may be amended only in writing executed by
         both Parties.

18.2     ENTIRETY OF AGREEMENT - This LICENSE sets forth the entire agreement
         and understanding between the Parties hereto as of the EFFECTIVE DATE
         with respect to AGENT and PRODUCT for their commercialization in the
         TERRITORY. The Parties agree that this LICENSE is in compliance with
         the OPTION conditions in all respects. Nevertheless, the OPTION shall
         remain in effect for development activities with regard to supplying
         reports or performance of remaining activities and until it expires on
         [*]. Also the CDA and OPTION shall remain in effect for activities done
         prior to the EFFECTIVE DATE.

18.3     SEVERABILITY - If any term or provision under this LICENSE is deemed
         invalid under the laws of a particular country or jurisdiction, the
         invalidity shall not invalidate the whole LICENSE but it shall be
         construed as if not containing that particular term or provision and
         the rights and obligations of the Parties shall be construed and
         enforced accordingly. The Parties shall negotiate in good faith a
         substitute provision in compliance with the law to retain as nearly as
         possible the Parties' intent in legally valid language. It is
         understood that a service agreement may be entered into between the
         Parties at a later date, which shall not modify this LICENSE.

18.4     WAIVERS, CUMULATIVE REMEDIES - A waiver by either Party of any term or
         condition of this LICENSE in any one instance shall not be deemed
         construed to be a waiver of such term or condition for any similar
         instance in the future or of any subsequent breach hereof. All rights,
         remedies, undertakings, obligations and agreements contained in this
         LICENSE shall be cumulative and none of them shall be a limitation of
         any other remedy, right, undertaking, obligation or agreement of either
         Party.

18.5     HEADINGS - Headings in this LICENSE are included herein for ease of
         reference and shall not affect the meaning of the provisions of this
         LICENSE, nor shall they have any other legal effect.

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                                        40

<PAGE>

18.6     OTHER DOCUMENTS - Each Party agrees to execute such additional papers
         or documents in customary legal form and to make such governmental
         filings or applications as may be necessary or desirable to effect the
         purposes of this LICENSE and carry out its provisions.

18.7     PUBLICITY - Neither DOW nor NEORX shall make the financial terms of
         this LICENSE public, except as required by law. In the event that a
         filing of a copy of this LICENSE with the U.S. Securities and Exchange
         Commission is required, then NEORX shall seek confidential treatment of
         information considered confidential by DOW. Any press release or
         publicity of this LICENSE shall be reviewed and approved by both
         Parties prior to any release.

18.8     INTERPRETATION - The Parties acknowledge and agree that: (a) each Party
         and its counsel reviewed and negotiated the terms and provisions of
         this LICENSE and have contributed to its revision; (b) the rule of
         construction to the effect that any ambiguities are resolved against
         the drafting Party shall not be employed in the interpretation of this
         LICENSE; and (c) the terms and revisions of this LICENSE shall be
         construed fairly as to all Parties and not in favor of or against any
         Party, regardless of which Party was generally responsible for the
         preparation of this LICENSE.

18.9     BANKRUPTCY - All rights and licenses granted under or pursuant to this
         LICENSE by DOW to NEORX are, and shall otherwise be deemed to be, for
         purposes of Section 365(n) of Title 11, U.S.C. (the "Bankruptcy Code"),
         licenses of rights to "intellectual property" as defined under Section
         101(60) of the Bankruptcy Code. The Parties agree that NEORX, as
         licensee of such rights under this LICENSE, shall retain and may fully
         exercise all of its rights and elections under the Bankruptcy Code.

         IN WITNESS WHEREOF, the Parties have duly executed duplicate originals
of this LICENSE by their appropriate authorized representative. This License may
be subject to management and/or Board approval by each Party. Upon signature
below such approval is indicated to have been obtained. Separate signature pages
are acceptable in facsimile form, and shall be accepted IN LIEU of original
signatures if time constraints prevent original signatures, provided each Party
receives a dated, signed, legible facsimile indicating the signatory for the
other Party.

THE DOW CHEMICAL COMPANY                   NEORX CORPORATION

                                        41

<PAGE>

By                                         By
  ---------------------------------          ---------------------------------
Name      Richard M. Gross JD              Name      Paul G. Abrams, MD, JD
Title:  Vice President, R&D                Title     Chief Executive Officer
Date                                       Date
    -------------------------------            -------------------------------


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