Efficacy Study of Oral Sapacitabine to Treat Acute Myeloid Leukemia in Elderly Patients

Inclusion Criteria: * A histologically or pathologically confirmed diagnosis of AML based on WHO classification which is previously untreated by systemic therapy or is in first relapse after achieving a complete remission to initial induction, consolidation and/or maintenance therapy or MDS with IPSS scores of intermediate -2 or higher risk risk which has been previously treated with hypomethylating agents * Age 70 years or older for AML and 60 years or older for MDS * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * Adequate renal function defined as serum creatinine equal to or less than 1.5 x upper limit of normal (ULN) * Adequate liver function defined as total bilirubin or direct bilirubin equal to or less than 1.5 x ULN; alanine aminotransferase (ALT or SGPT) equal to or less than 2.5 x ULN (5 x ULN if tumor has affected the liver) * Life expectancy reasonably adequate for evaluating the treatment effect * Patient must be able to swallow capsules * Patients must be at least 2 weeks from prior systemic therapy, radiation therapy, major surgery, or other investigational therapy, and have recovered from clinically significant toxicities of these prior treatments * All men and women of reproductive potential must agree to practice effective contraception for 4 weeks prior to study entry, during the entire study period and for one month after the study unless documentation of infertility exists * Ability to understand and willingness to sign the informed consent form Exclusion Criteria: * AML is of the sub-type of acute promyelocytic leukemia * Having received more than one induction systemic therapy for AML or having received a standard dose or high dose ara-C containing regimen for MDS * Patients with known central nervous system (CNS) involvement by leukemia * Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, active cancer(s) other than AML, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. Patients receiving intravenous antibiotics for infections that are under control may be included in this study * Known to be HIV-positive