Patients receive oral panobinostat once daily on days 1, 3 and 5; 8, 10, and 12; 15, 17, and 19; and 22, 24, and 26. Patients also receive oral imatinib mesylate once daily on days 1-28. Treatment repeats every 21 or 28 days for up to 4 courses in the absence of disease progression or unacceptable toxicity.