XOMA'S CHAIRMAN LEAVES FOR PRIZM

Steven Mendell has resigned as chairman of the Berkeley, Calif.,company to take up the reins as president and chief executiveofficer of privately held Prizm Pharmaceuticals of San Diego,Xoma (NASDAQ:XOMA) announced Wednesday. John Castello,already Xoma's president and chief executive officer, will addthe title of chairman. Mendell will continue as a director of thecompany.

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