The purposes of this study are:

• To determine the maximum tolerated dose (MTD) of SAHA administered every 12 hours for 14 consecutive days followed by 7 days of rest during the first two cycles (i.e., first 6 weeks) in patients with advanced multiple myeloma;
• To assess the safety and overall response rate to SAHA in patients with advanced multiple myeloma.

Inclusion Criteria:

• Adult patients with refractory or relapsed multiple myeloma, ECOG performance status 0-2 (ECOG)
• Adequate bone marrow reserve
• Adequate hepatic and renal function
• Ability to swallow capsules
• 3 weeks or more from prior chemotherapy and have recovered from prior toxicities

Exclusion Criteria:

• Patients who plan to go for bone marrow transplant within 4 weeks of start of treatment
• Patients with prior treatment with other investigational agents with a similar anti-tumor mechanism
• Patients with other active/uncontrolled clinically significant illnesses
• Pregnant or nursing female patients