Despite recent insights into the biology of multiple myeloma (MM) and novel treatment it remains incurable. New therapies are therefore urgently needed. Adaphostin has already shown remarkable efficacy in patients with chronic myelocytic leukaemia (CML), including those resistant to Glivec, a new drug that has revolutionized treatment of CML. My preliminary laboratory data demonstrate significant anti-MM activity of adaphostin. In the proposed studies, I will delineate the molecular mechanisms of adaphostin-triggered MM killing to provide the preclinical rationale for its clinical use to improve patient outcomes.