To Demonstrate Superiority of Decitabine Over Azacitidine in Subjects With Intermediate- or High-risk MDS.

Inclusion Criteria

Subjects who meet all of the following criteria may be included in the study:

Must have a diagnosis of primary myelodysplastic syndromes (MDS) of Intermediate-1 transfusion dependent, Intermediate-2, or High-risk [defined by International Prognostic Scoring System (IPSS) score of ≥0.5] and recognized French-American-British (FAB) classifications
Male or female, 18 years of age or older with signed informed consent
Adequate renal function
Demonstrated normal liver function
Female subjects of childbearing age must have negative pregnancy test within 1 week of study entry and agree to use adequate contraception for the duration of the trial and for a minimum of six months after last dose of decitabine or azacitidine received.
Male subjects must agree to use adequate contraception for the duration of the trial and for a minimum of six months after last dose of decitabine or azacitidine received.

Exclusion Criteria

Subjects who meet any of the following criteria will be excluded from participation in the study:

Current use of radiotherapy for extramedullary disease for 2 weeks prior to entering study (permitted if > 2 weeks from study entry and if recovered from toxic effects of therapy)
Systemic fungal, bacterial, or viral infection which is not controlled (i.e., ongoing signs or symptoms of infection and without improvement despite appropriate treatment)
Pregnancy or current lactation
Significant concurrent disease, illness, or psychiatric disorder
Treatment with an investigational agent 30 days prior to the first dose of decitabine or azacitidine