Safety, Pharmacokinetics, and Pharmacodynamics of Oral Azacitidine in Subjects With Myelodysplastic Syndromes, Chronic Myelomonocytic Leukemia and Acute Myelogenous Leukemia

Inclusion Criteria: * 18 years or older. * Diagnosis of low or Int-1 risk MDS * Low platelet count, and/or low hemoglobin, and/or RBC transfusion-dependent and/or platelet transfusion-dependent * ECOG Performance status 0-2 * Standard safety inclusion for serum creatinine, AST, ALT, bilirubin. * Serum bicarbonate greater than or equal to 20 mEq/L. * Use of acceptable birth control. * Signed, written informed consent. Exclusion Criteria: * Diagnosis of acute PML. * Previous or concurrent malignancy. * Prior treatment with azacitidine or other demethylating agents. * Treatment with any anticancer therapy or investigational drugs within 21 days. * Hypersensitivity to azacitidine or mannitol. * Presence of GI disease. * Active, uncontrolled infection. * Known Human Immunodeficiency Virus (HIV) or Hepatitis C, or known active viral Hepatitis B. * Breastfeeding or Pregnant females; * Presence of serious illness, medical condition, or other medical history which would be likely to interfere with a subject's participation in the study or with the interpretation of the results. * Current congestive heart failure (NY Heart Association Class III-IV), unstable angina or angina requiring surgical or medical intervention within 6 months, myocardial infarct within 6 months, or uncontrolled cardiac arrhythmia.