Panobinostat (LBH589) and Imatinib Mesylate in Treating Patients With Previously Treated Chronic Phase Chronic Myelogenous Leukemia

OBJECTIVES: Primary * To determine the safety and tolerability of LBH589 given in combination with imatinib mesylate in CML patients who are in Major Cytogenetic Remission (MCR) with residual BCR-ABL positive cells after at least 1 year of daily imatinib mesylate treatment. * To determine the maximum tolerated dose (MTD) and dose-limiting toxicity of LBH589 given in combination with imatinib mesylate in CML patients. Secondary * To study the effect of LBH589 given in combination with imatinib mesylate on cytogenetic response status and BCR-ABL levels in CML patients in major cytogenetic remission on imatinib mesylate treatment. Tertiary * To study the effect of LBH589 given in combination with imatinib mesylate on residual BCR-ABL positive primitive progenitors in CML patients in major cytogenetic remission on imatinib mesylate treatment. OUTLINE: This is dose-escalation study of panobinostat. 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. After completion of study treatment, patients are followed up at 1 month and then every 3 months for up to 1 year.