XOMA Announces Planned Retirement of Chief Executive Officer

28-02-2007: Jack Castello, Chairman of the Board, President and Chief Executive Officer of XOMA Ltd. , announced his plans to retire. Mr. Castello, 70, chose to announce his retirement plans now to allow adequate time to find the best qualified individual to succeed him and make the management change as smooth as possible. He will continue to serve in his present capacities during the candidate search and transition period.

Denny Van Ness, a member of XOMA's Board of Directors, stated, "Jack Castello has made a significant contribution to XOMA in guiding it through both tough times and good times. He has transformed XOMA into a leading therapeutic antibody discovery, development and manufacturing company."