To evaluate the response to chemotherapy with the drug decitabine combined with rapamycin in the treatment of relapsed or refractory acute myeloid leukemia in patients of all ages, and in the treatment of newly diagnosed leukemia in those who are older than 65 when diagnosed.

To determine the efficacy of decitabine followed by Rapamycin in previously untreated elderly patients not able to receive standard chemotherapy or in patients with relapsed or refractory AML, through measurement of Complete Remission (CR), Complete Remission Incomplete Platelet Recovery (CRp), Partial Remission (PR), and event free and overall survival (Arm A).

To determine the safety of administration of decitabine with escalating doses of Ribavirin in elderly leukemia patients or patients with relapsed/refractory disease with M4/M5 subtypes anticipated to express high eukaryotic translation initiation factor 4E (eIF4E) at diagnosis (Arm B).

To establish effect of these sequential treatments on expression of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt /mTOR) pathway proteins and on eukaryotic translation initiation factor 4E (eIF4E) activation through Western blot and phospho-flow methodologies.

To correlate the clinical response with baseline expression of phospho-p70S6 Kinase/phosphorylated protein kinase B (pAKT) and with the in vitro inhibitory effects of mammalian target of rapamycin (mTOR) inhibition with rapamycin or ribavirin on the level of downstream effectors.

To determine whether a leukemia stem cell phenotype is inhibited by the sequential administration of decitabine/rapamycin or decitabine/ribavirin.

Inclusion Criteria:

4.1.1 Age >/= 18 4.1.2 Diagnosis of AML according to World Health Organization (WHO) criteria except acute promyelocytic leukemia AND 4.1.3 Refractory AML defined as failure to achieve Complete Remission (CR) after 2 cycles of induction chemotherapy or persistence of > 40% bone marrow blasts after one cycle of chemotherapy induction OR 4.1.4 Relapsed AML defined as any evidence of disease recurrence after achieving a documented first or greater Complete Remission (CR) OR 4.1.5 Relapsed AML after stem cell transplantation. 90 days (since stem cell infusion) must have elapsed between transplant and emergence of recurrent AML OR 4.1.6 Newly diagnosed AML in a patient >65 years old not considered fit for standard 7+ 3 chemotherapy or who declines such therapy after discussion of therapeutic options available.

4.1.7 Eastern Cooperative Oncology Group (ECOG) performance status <3

Exclusion Criteria:

4.2.1 Abnormal renal function as evidenced by a calculated creatinine clearance ≤ 30 ml/min (Cockcroft-Gault formula (Appendix 2) 4.2.2 Abnormal liver function: Bilirubin >2.0 mg/dl, transaminase(s) more than 2.5x the upper limits of normal 4.2.3 Active systemic infection not responding to antibiotics 4.2.4 Known diagnosis of human immunodeficiency virus infection (HIV) 4.2.5 Patients who are post-allogeneic transplantation should not have active Graft vs. Host Disease (GVHD) greater than grade 1 of skin at time of enrollment. They may have had donor lymphocyte infusion (DLI) but not within 4 weeks of beginning the study.

4.2.6 Pregnant or breastfeeding female subjects 4.2.7 Known or suspected Central Nervous System (CNS) leukemia involvement; past involvement is not an exclusion.

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2 years