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

Inclusion Criteria:

Ability to provide written informed consent obtained prior to participation in the study and any related procedures being performed
CML CP patients who have been treated with and tolerated Imatinib for 1 year or more, have achieved at least major cytogenetic response and continue to be BCR-ABL positive (Patients should be receiving Imatinib at a dose of 400 daily at the time of entry into the study)
ANC and PLT need to be in the normal range
Serum albumin >= 3g/dL
AST/SGOT and ALT/SGPT =< 2.5 x upper limit of normal (ULN)
Serum bilirubin =< 1.5 x ULN
Serum creatinine =< 1.5 x ULN or 24-hour creatinine clearance >= 50 ml/min
Serum potassium >= lower limit of normal (LLN)
Serum phosphorus >= LLN
Serum total calcium (corrected for serum albumin) or serum ionized calcium >= LLN
Serum magnesium >= LLN
ECOG performance status of =< 2

Exclusion Criteria:

Prior treatment with an HDAC inhibitor
Patient who have been treated with Imatinib < 1 year or patients are currently being treated with Imatinib at a dose > 400 mg daily
Impaired cardiac function including any one of the following: Screening ECG with a QTc > 450 msec; Patients with congenital long QT syndrome; History or presence of sustained ventricular tachycardia; Any history of ventricular fibrillation or torsades de pointes; Bradycardia defined as heart rate < 50 beats per minute (patients with a pacemaker and heart rate >= 50 beats per minute are eligible); Patients with a myocardial infarction or unstable angina within 6 months of study entry; Congestive heart failure (NY Heart Association class III or IV); Right bundle branch block and left anterior hemiblock (bifascicular block)
Uncontrolled hypertension
Concomitant use of drugs with a risk of prolonging the QT interval or inducing torsades de pointes
Concomitant use of CYP3A4 inhibitors
Patients with unresolved diarrhea > CTCAE grade 1
Impairment of gastrointestinal (GI) function or GI disease that may significantly alter the absorption of oral LBH589
Other concurrent severe and/or uncontrolled medical conditions
Patients who have received chemotherapy, any investigational drug or undergone major surgery < 4 weeks prior to starting study drug or who have not recovered from side effects of such therapy
Concomitant use of any other anti-cancer therapy or radiation therapy
Patients being treated with Coumadin (unless patients who require anticoagulation can be switched to a low-molecular weight or standard heparin)
Female patients who are pregnant or breast feeding or patients of reproductive potential not willing to use a double method of contraception including a barrier method (i.e. condom) during the study and 3 months after the end of treatment (Women of childbearing potential [WOCBP] must have a negative serum pregnancy test within 7 days of the first administration of oral LBH589)
Male patients whose sexual partners are WOCBP not willing to use a double method of contraception including condom during the study and 3 months after the end of treatment
Patients with a history of another primary malignancy within 5 years other than curatively treated CIS of the cervix, or basal or squamous cell carcinoma of the skin
Patients with known positivity for human immunodeficiency virus (HIV) or hepatitis C; baseline testing for HIV and hepatitis C is not required
Patients with any significant history of non-compliance to medical regimens or with inability to grant a reliable informed consent