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                                                                  Exhibit 10.4


                                AMENDMENT TO
                        NONEXCLUSIVE LICENSE AGREEMENT



     THIS AMENDMENT (this "Amendment") is made as of August 8, 2001 by and
between Eos Biotechnology, Inc., a corporation organized under the laws of the
State of Delaware (EOS) and Seattle Genetics, Inc., a corporation organized
under the laws of the State of Delaware ("SGI").

                                   BACKGROUND


     WHEREAS, EOS and SGI have entered into that certain Collaboration
Agreement effective as of June 5, 2001 (the "Agreement"); and

     WHEREAS, EOS and SGI have agreed to amend the Agreement as set forth
herein.

                                      TERMS

     NOW, THEREFORE, the parties agree to as follows:

1.   All capitalized terms not defined herein shall have the definitions
     given to them in the Agreement.

2.   Article 9.1 of the Agreement shall be deleted in its entirety and
     replaced with the following:

     "ARTICLE 9 - PAYMENTS, LATE PAYMENTS"

     9.1    PAYMENT TERMS.

     Royalties shown to have accrued by each Report provided for under
Article 8 of this Agreement shall be due on the date such Report is due.
Payment of royalties in whole or in part may be made in advance of such date.
Past due payments shall accrue at a rate of ([***]) per annum, or the maximum
applicable rate permitted by law, whichever is lower, unless occurring as a
result of an event the Parties agree constitutes an Event of Force Majeure or
as a result of a good faith dispute the Parties regarding performance or
breach of their obligations hereunder.

3.   Except as set forth herein, all terms, provisions and conditions of the
     Agreement shall remain in full force and effect.

4.   This Amendment shall be governed by and construed in accordance with
     the laws of the State of Washington without regard to conflict of laws
     rules or principles.

5.   This Amendment may be executed and delivered in any number of separate
     counterparts, each of which shall be deemed an original and all of which
     taken together shall constitute one and the same original agreement.


[***] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

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     IN WITNESS WHEREOF, the parties have caused this Amendment to be
executed by their duly authorized officers as of the date first set forth
above.


                                          SEATTLE GENETICS, INC.


                                          By: /s/ H. Perry Fell
                                              ------------------------
                                              Name: H. Perry Fell
                                              Title: CEO


                                          EOS BIOTECHNOLOGY, INC.


                                          By: /s/ David W. Martin, Jr., M. D.
                                              ------------------------
                                              Name: David W. Martin, Jr., M. D.
                                              Title: President and CEO