BERKELEY, Calif., May 3, 2011 (GLOBE NEWSWIRE) -- XOMA Ltd. (Nasdaq:XOMA), a leader in the discovery and development of antibody therapeutics, announced that the company will host a webcast conference call on Thursday, May 5, 2011 at 4:30 p.m. Eastern time to discuss first quarter 2011 financial results and provide a general business update.