Steven B. Engle has been named president, chief executive officer and a member of the board of directors of Xoma Ltd. Mr. Engle succeeds Jack Castello, the company’s former president and chief executive officer, who announced his retirement plans earlier this year. Mr. Castello will remain with the company as non-executive chairman of the board during a transition period, expected to run through October of 2007. “On behalf of the Xoma Board, I couldn’t be more pleased that S...