1. Patients must have cytologically (or by flow cytometry) documented relapsed/refractory Acute Myeloid leukemia or Acute Lymphoid leukemia for which no standard therapy is anticipated to result in a durable remission. Chronic Myeloid leukemia in blast crisis who progress through Gleevec® or is intolerant to Gleevec® or other FDA approved BCR-ABL Tyrosine Kinase Inhibitors. Patients with untreated AML or ALL who are electing not to receive standard therapy are also eligible. Relapsed/refractory leukemia patients may combination after 1 course of chemotherapy. In addition,leukemia secondary to pre-existing hematologic disorders high-grade myelodysplastic syndromes are also eligible.