GROUP I (PRIMED): Patients receive decitabine intravenously (IV) over 1 hour on days -14 to -5. Patients also receive filgrastim subcutaneously (SC) on days 0-5, cladribine IV over 2 hours on days 1-5, cytarabine IV over 2-4 hours on days 1-5 and mitoxantrone hydrochloride IV over 60 minutes on days 1-3.