[*]indicates that a confidential portion of the text of this agreement has been
omitted


                      FIFTH AMENDMENT TO LICENSE AGREEMENT


     This Fifth Amendment to License Agreement (hereinafter "Amendment") is made
and effective on June 25, 1999, by and between XOMA TECHNOLOGY LTD., a company
organized and existing under the laws of Bermuda and having an office at 2910
Seventh Street, Berkeley, California 94710 (hereinafter "CORPORATION"), and NEW
YORK UNIVERSITY, a corporation organized and existing under the laws of the
State of New York and having a place of business at 70 Washington Square South,
New York, New York 10012 (hereinafter "NYU").

                                   WITNESSETH


     WHEREAS, CORPORATION and NYU entered into a certain agreement made and
effective as of August 6, 1990, as amended and restated on September 1, 1993 and
as subsequently amended on August 1, 1996, June 12, 1997 and December 23, 1998
(as so amended and restated, the "Agreement"), pursuant to which, inter alia,
CORPORATION undertook to sponsor the NYU Research Project (as such term is
defined in the Agreement) and NYU granted to CORPORATION the License (as such
term is defined in the Agreement); and



<PAGE>
                                      -2-


     WHEREAS, CORPORATION and NYU wish to amend the Agreement as specified
herein;

     NOW, THEREFORE, in consideration of the premises and the covenants,
conditions and promises set forth below, the parties hereto hereby agree as
follows:

     1.   Except as expressly provided for herein, all terms and conditions of
          the Agreement shall remain in full force and effect.

     2.   Terms which are defined in the Agreement shall have the same meanings
          when used in this Amendment, unless a different definition is given
          herein.

     3.   The second line of Subsection 7.c.(2) of the Agreement shall be, and
          hereby is, amended by adding the following language after the
          semicolon:

          provided, that such sublicense may also be assignable to the successor
          or assignee of that portion of the sublicensee's business to which
          such sublicense relates so long as NYU receives reasonably prompt
          notice of such assignment and a copy of the formal written assignment,
          which shall include an undertaking by the assignee to perform the
          original sublicensee's obligations under the sublicense;

     4.   The second line of Subsection 7.c.(3) of the Agreement shall be, and
          hereby is, amended by adding the



<PAGE>
                                      -3-


          following language after the semicolon and before the word "and":

          provided, that in the case of a sublicense granted to a sublicensee
          for [*] the sublicense may also provide for the grant of further
          sublicenses to up to one sublicensee in each country of the territory
          covered by such sublicense so long as any such further sublicense is
          granted only on terms including those set forth in the last sentence
          of this Subsection 7.c. and such further sublicensee is included in
          the term "sublicensee" for purposes of Subsections 9.a.(3), (4) and
          (5), 9.b. and 9.c. hereof;

     5.   The last line of Subsection 9.a.(2) of the Agreement (after giving
          effect to the Third Amendment thereto) shall be, and hereby is,
          amended by adding the following language after the word "and":

          in the case of a sublicense between CORPORATION and a third party for
          [*] and

     6.   The first clause (i.e., the language preceding the first colon) of
          Subsection 9.a.(3) of the Agreement shall be, and hereby is, amended
          to read in its entirety as follows:

          (a) a royalty of [*] of the Net Sales of any Licensed Product
          described in Section 1.1(aa) or (bb) and sold by CORPORATION or its
          sublicensees (including CORPORATION Entity) for human diagnostic,
          prophylactic and/or therapeutic uses other than [*] for as long as
          CORPORATION maintains the License except (in the case of the foregoing
          clause (a), (b) or (c)) as follows in (i) and (ii) below


<PAGE>
                                      -4-


     7.   The first clause (i.e., the language preceding the first colon) of
          Subsection 9.a.(4) of the Agreement shall be, and hereby is, amended
          to read in its entirety as follows:

          (a) a royalty of [*] of the Net Sales of any Licensed Product
          described in Section 1.1(cc) or (dd) and sold by CORPORATION or its
          sublicensees (including CORPORATION Entity) for human diagnostic,
          prophylactic and/or therapeutic uses other than [*] for as long as
          CORPORATION maintains the License except (in the case of the foregoing
          clause (a), (b) or (c)) as follows in (i) and (ii) below

     8.   Subsection 9.a.(5) of the Agreement shall be, and hereby is, amended
          to read in its entirety as follows:

          If any Licensed Product is covered solely by a CORPORATION Patent then
          the royalty owed by the CORPORATION to NYU with respect to such
          Licensed Product shall be [*] of the Net Sales of such Licensed
          Product sold by CORPORATION or its sublicensees (including CORPORATION
          Entity) for human diagnostic, prophylactic and/or therapeutic uses
          other than [*] for as long as CORPORATION maintains the License.

     9.   The seventeenth line (i.e., the end of the third sentence) of Section
          9.b. of the Agreement shall be, and hereby is, amended by adding a
          semicolon and the following language after the words "Combination
          Product":


<PAGE>
                                      -5-


          provided, that this sentence shall not apply to Net Sales of Licensed
          Products for [*]

     10.  The last line of Section 9.c. of the Agreement shall be, and the same
          hereby is, amended by adding a semi-colon and the following language
          after the word "CORPORATION":

          provided, that, in the event the relevant sublicense does not contain
          provisions requiring the sublicensee to provide such reports to NYU,
          then NYU shall not have the right to have CORPORATION undertake to
          have the sublicensee provide any such reports and to have CORPORATION
          conduct any such audit pursuant to the preceding clauses of this
          sentence, but instead shall have the right to have the books of
          accounts, records and other relevant documentation of the sublicensee
          inspected by independent auditors on the same terms as set forth in
          the first five sentences of this Subsection 9.c.

     11.  The last line of Subsection 9.e. of the Agreement shall be, and hereby
          is, amended by adding a semi-colon and the following language after
          the word "non-exclusive":

          provided, that, without effecting the foregoing right of termination,
          NYU shall have no such right to declare the License to be
          non-exclusive with respect to Licensed Products for the mitigation,
          treatment or prevention of ophthalmic infection in humans and other
          mammals in the event CORPORATION fails to make any such payment

     12.  Section 18.a.(iv) of the Agreement shall be, and hereby is, amended to
          read in its entirety as follows:


<PAGE>
                                      -6-


          (iv) CORPORATION has changed its legal domicile from Delaware to
          Bermuda and has also assigned this Agreement in whole to XOMA
          Technology Ltd., a Bermuda company wholly owned by CORPORATION
          ("XTL"), and NYU hereby consents to such assignment. In addition, (a)
          CORPORATION's rights and obligations hereunder relating to the
          manufacture, use and sale of Licensed Products [*] have been
          transferred from XTL to XOMA Ireland Limited, incorporated under the
          laws of Ireland and wholly owned by CORPORATION ("XIL"), which in turn
          has granted a nonexclusive sublicense hereunder for the manufacture of
          Licensed Products for [*] to XOMA (US) LLC, a Delaware limited
          liability company wholly owned by CORPORATION ("XUS"); (b) from time
          to time CORPORATION's other rights and obligations hereunder relating
          to other fields of use and/or indications may be transferred from XTL
          to XIL, which in turn may grant nonexclusive sublicenses hereunder for
          the manufacture of Licensed Products in such other fields of use
          and/or indications to XUS; and (c) NYU hereby consents to all of the
          foregoing transfers and license grants. Notwithstanding the foregoing,
          CORPORATION (now understood to mean XTL, XIL and XUS, each as to their
          respective rights and obligations hereunder) agrees to comply with the
          applicable provisions of the Bayh-Dole Act of 1980 and the regulations
          promulgated thereunder including, without limitation, the requirement
          that any Licensed Products using the subsequent technology will be
          manufactured substantially in the United States to the extent required
          by 35 U.S.C. ss. 204.


     13.  This Amendment may be executed in one or more counterparts, each of
          which shall be an original and all of which shall constitute together
          the same document.




<PAGE>
                                      -7-


     IN WITNESS WHEREOF, the parties hereto have executed this Amendment as
follows:

NEW YORK UNIVERSITY                         XOMA TECHNOLOGY LTD.

By:______________________________________   By:________________________________
        Isaac T. Kohlberg                          G. James Reynolds
        Assistant Dean and Vice                    Director
        President for Industrial Liaison

                                            XOMA IRELAND LIMITED

                                            SIGNED by

                                            ----------------------------
                                            Alan Kane, Director,
                                            duly authorized for and on behalf
                                            of XOMA IRELAND
                                            LIMITED in the presence of:

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