Study of Three Different Schedules of Low-Dose Decitabine in Myelodysplastic Syndrome (MDS)

Inclusion Criteria:

1. MDS and 5% or more marrow blasts, or IPSS risk intermediate 1-2 or high risk; or chronic myelomonocytic leukemia
2. Performance status 0-2 (Eastern Cooperative Oncology Group (ECOG) scale); adequate hepatic (bilirubin \< 2 mg/dl) and renal functions (creatinine \<2mg/dl); New York Heart Association (NYHA) cardiac status III-IV excluded.
3. Signed informed consent
4. No prior intensive combination chemotherapy or high-dose ara-C (\>/= 1g/m2 per dose). Prior biologic therapies, targeted therapies and single agent chemotherapy allowed.
5. Patients must have been off chemotherapy for 2 weeks prior to entering this study and recovered from the toxic effects of that therapy, unless there is evidence of rapidly progressive disease. Use of Hydroxyurea for patients with rapidly proliferative disease is allowed for the first two weeks on therapy.

Exclusion Criteria:

1. Nursing and pregnant females are excluded. Patients of childbearing potential should practice effective methods of contraception. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.
2. Patients with active and uncontrolled infections
3. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, or psychiatric illness/social situations that would limit compliance with study requirements