LBH589 Plus Decitabine for Myelodysplastic Syndromes (MDS) or Acute Myeloid Leukemia (AML)

Inclusion Criteria: * AML (except t(15;17), inv(16) or t(8;21) and variants) or high risk MDS (IPSS Int-2 or High) diagnosed according to WHO criteria (see Appendix 1) * Age ≥ 60 years old * Not a candidate for allogeneic stem cell transplantation within next 12 weeks * Ability to provide written informed consent, obtained prior to participation in the study and any related procedures being performed * Patients must meet the following laboratory criteria: * Serum albumin ≥ 3 g/dL * Aspartate aminotransferase (AST)/SGOT and alanine aminotransferase (ALT)/SGPT ≤ 2.5 x upper limit of normal (ULN) ) or ≤ 5.0 x ULN if the transaminase elevation is due to leukemic involvement * 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, thyroid stimulating hormone (TSH) and free thyroxine (T4) within normal limits (WNL) (patients may be on thyroid hormone replacement) * Baseline MUGA or ECHO must demonstrate left ventricular ejection fraction (LVEF) ≥ the lower limit of the institutional normal. * Eastern Cooperative Oncology Group (ECOG) Performance Status of ≤ 2 Exclusion Criteria: * Prior treatment for MDS / AML with Histone deacetylase (HDAC) inhibitor or hypomethylating agent (e.g., Decitabine, azacitidine etc.) * Active central nervous system (CNS) involvement with MDS/AML * Impaired cardiac function including any one of the following: * Screening electrocardiogram (ECG) with a QTc \> 450 msec confirmed by central laboratory prior to enrollment to the study * Patients with congenital long QT syndrome * History 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 (bifasicular block) * Uncontrolled hypertension * Concomitant use of drugs with a risk of causing torsades de pointes * 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 or any investigational drug \< 2 weeks or hydroxyurea \< 48 hours prior to starting study drug or who have not recovered from side effects of such therapy. * Concomitant use of any anti-cancer therapy or radiation therapy * Male patients whose sexual partners are women of child bearing potential (WOCBP) not using effective birth control * 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 * Patients who will need valproic acid for any medical condition during the study or within 5 days prior to first LBH589 treatment * Patients who have received targeted agents within 2 weeks or within 5 half-lives of the agent and active metabolites (whichever is longer) and who have not recovered from side effects of those therapies * Patients who have undergone major surgery ≤ 4 weeks prior to starting study drug or who have not recovered from side effects of such therapy.