Inclusion Criteria:

- Have a diagnosis of refractory anemia with excess blasts or refractory anemia with
excess blasts in transformation according to the French-American-British
classification system for myelodysplastic syndromes (MDS) and a relatively high risk
of acute myeloid leukemia (AML) transformation, with an International Prognostic
Scoring System score of INT-2 or High.

- Be 18 years of age or older

- Have a life expectancy of at least 3 months

- Be unlikely to proceed to bone marrow or stem cell transplantation therapy following
remission

- Have serum bilirubin levels less than or equal to 1.5 times the upper limit of normal
range for the laboratory

- Have serum glutamic-oxaloacetic transaminase (aspartate aminotransferase) or serum
glutamic-pyruvic transaminase (alanine aminotransferase) levels less than or equal to
2 times the upper limit of normal (unless these are considered to be related to
transfusion-induced secondary hemosiderosis)

- Have serum creatinine levels less than or equal to 1.5 times the upper limit of
normal

Exclusion Criteria:

- Secondary myelodysplastic syndromes (MDS)

- Prior treatment with azacitidine;

- Prior history of acute myeloid leukemia (AML);

- Malignant disease diagnosed within prior 12 months;

- Metastatic disease;

- Hepatic tumors;

- Radiation, chemotherapy, cytotoxic therapy for non-MDS conditions within prior 12
months;

- Prior transplantation or cytotoxic therapy to treat MDS;

- Serious medical illness likely to limit survival to 12 months or less;

- Treatment with erythropoietin or myeloid growth factors during prior 21 days or
androgenic hormones during prior 13 days;

- Active HIV, viral hepatitis type B or C;

- Treatment with investigational drugs during prior 30 days;

- Within the 28-day screening period, documented red cell folate deficiency, as
evidenced by red blood cell folate (not serum folate) or vitamin B12 deficiency