UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                 AMENDMENT NO. 4
                                       on
                                   FORM 8-K/A



                                 CURRENT REPORT


                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934


       Date of Report (Date of Earliest Event Reported): November 26, 2001


                                    XOMA Ltd.
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             (Exact name of registrant as specified in its charter)


                                     BERMUDA
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                 (State or other jurisdiction of incorporation)


              0-14710                                  52-2154066
     (Commission File Number)               (IRS Employer Identification No.)

2910 Seventh Street, Berkeley, California                      94710
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(Address of principal executive offices)                     (Zip code)

Registrant's telephone number, including area code         (510) 204-7200



--------------------------------------------------------------------------------
          (Former name or former address, if changed since last report)






Item 5. Other Events


     As previously announced on November 26, 2001, XOMA Ltd. ("XOMA") has
entered into a development and license agreement with Millennium
Pharmaceuticals, Inc. ("Millennium").

     Under the related investment agreement, Millennium committed to purchase,
at XOMA's option, up to $50 million worth of XOMA common shares over the 30
months following the effective date of the investment agreement, through a
combination of convertible debt and equity at then prevailing market prices. As
previously announced, on May 16, 2003, XOMA and Millennium agreed to delay the
maturity of the convertible debt until February 26, 2004 and to adjust the
timing of Millennium's obligation to purchase the remaining $37.5 million worth
of XOMA common shares. As previously announced, on October 10, 2003, XOMA
announced that it discontinued development of MLNM2201 (formerly known as
LDP-01), one of the two products being developed under its collaboration with
Millennium, which had the effect of reducing Millennium's obligation to purchase
XOMA common shares under the investment agreement by 40% from up to $33.5
million remaining to up to $20.1 million. On February 24, 2004, XOMA and
Millennium agreed to delay the maturity of the convertible debt until April 15,
2004 (or the third business day after the date the related registration
statement is declared effective, if later) and to further adjust the timing of
Millennium's obligation to purchase the remaining $14.7 million worth of XOMA
common shares. At each of four subsequent closings over the following 13 months,
XOMA may issue up to $3,675,000 worth of its common shares. At each closing, the
precise number of shares to be purchased by Millennium will be determined using
a formula based on the average of certain sale prices per common share as
reported on the Nasdaq National Market for a specified period of time prior to
the applicable closing date (subject to certain adjustments and limitations).
The formula is intended to reflect the current market price per common share at
the time of each closing, without any discount or premium.

     A copy of the letter agreement is attached hereto as Exhibit 8 and
incorporated herein by reference.


Item 7. Exhibits


1.   Press Release dated November 26, 2001.*

2.   Development and License Agreement dated as of November 26, 2001 by and
     among Millennium Pharmacueticals Inc., XOMA (US) LLC and XOMA Ireland
     Limited (with certain confidential information omitted, which omitted
     information is the sub-



                                      -2-


     ject of a confidential treatment request and has been filed separately with
     the Securities and Exchange Commission).*

3.   Investment Agreement dated as of November 26, 2001 by and among XOMA Ltd.,
     Millennium Pharmaceuticals, Inc. and mHoldings Trust (with certain
     confidential information omitted, which omitted information is the subject
     of a confidential treatment request and has been filed separately with the
     Securities and Exchange Commission).*

4.   Registration Rights Agreement dated as of November 26, 2001 by and among
     XOMA Ltd., Millennium Pharmaceuticals, Inc. and mHoldings Trust (with
     certain confidential information omitted, which omitted information is the
     subject of a confidential treatment request and has been filed separately
     with the Securities and Exchange Commission).*

5.   Convertible Subordinated Promissory Note dated November 26, 2001 (with
     certain confidential information omitted, which omitted information is the
     subject of a confidential treatment request and has been filed separately
     with the Securities and Exchange Commission).*

6.   Letter Agreement dated May 16, 2003 by and among XOMA Ltd., Millennium
     Pharmaceuticals, Inc. and mHoldings Trust.*

7.   Press Release dated May 20, 2003.*

8.   Letter Agreement dated February 24, 2004 by and between XOMA Ltd. and
     Millennium Pharmaceuticals, Inc.

____________________________

*    Previously filed.




                                      -3-


                                    SIGNATURE


     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

Dated:  February 24, 2004           XOMA LTD.



                                    By:  /s/ Christopher J. Margolin
                                         ---------------------------------
                                         Christopher J. Margolin
                                         Vice President, General
                                         Counsel and Secretary








                                  EXHIBIT INDEX


Number   Description
------   -----------

1.   Press Release dated November 26, 2001.*

2.   Development and License Agreement dated as of November 26, 2001 by and
     among Millennium Pharmacueticals Inc., XOMA (US) LLC and XOMA Ireland
     Limited (with certain confidential information omitted, which omitted
     information is the subject of a confidential treatment request and has been
     filed separately with the Securities and Exchange Commission).*

3.   Investment Agreement dated as of November 26, 2001 by and among XOMA Ltd.,
     Millennium Pharmaceuticals, Inc. and mHoldings Trust (with certain
     confidential information omitted, which omitted information is the subject
     of a confidential treatment request and has been filed separately with the
     Securities and Exchange Commission).*

4.   Registration Rights Agreement dated as of November 26, 2001 by and among
     XOMA Ltd., Millennium Pharmaceuticals, Inc. and mHoldings Trust (with
     certain confidential information omitted, which omitted information is the
     subject of a confidential treatment request and has been filed separately
     with the Securities and Exchange Commission).*

5.   Convertible Subordinated Promissory Note dated November 26, 2001 (with
     certain confidential information omitted, which omitted information is the
     subject of a confidential treatment request and has been filed separately
     with the Securities and Exchange Commission).*

6.   Letter Agreement dated May 16, 2003 by and among XOMA Ltd., Millennium
     Pharmaceuticals, Inc. and mHoldings Trust.*

7.   Press Release dated May 20, 2003.*

8.   Letter Agreement dated February 24, 2004 by and between XOMA Ltd. and
     Millennium Pharmaceuticals, Inc.

____________________________

*    Previously filed.