A Study of Ribavirin to Treat M4 and M5 Acute Myelocytic Leukemia

Inclusion Criteria: * A diagnosis of acute myeloid leukemia (AML), either M4 or M5 subtype de novo or resulting from a transformation from MDS or a myeloproliferative disorder. * Patients with AML who (a) have failed primary therapy -defined as failing two induction chemotherapies, (b) have relapsed or (c) are not suitable for intensive induction chemotherapy will be eligible. OR * Patients with AML blast crisis from CML if they are not suitable candidates for intensive induction chemotherapy or have failed imatinib mesylate OR * Patients with secondary AML after MDS if they are not suitable candidates for intensive induction chemotherapy. * ECOG 0,1,2, or 3 * Life expectancy \> 12 weeks. * Adequate renal and hepatic function Exclusion Criteria: * Uncontrolled central nervous system involvement by AML * Active cardiovascular disease as defined by NYHA class III-IV categorization. * Intercurrent illness or medical condition precluding safe administration of ribavirin. * Received any previous therapy within 28 days prior to study entry.Hydrea is permitted but must be stopped 7 days prior to starting study drug. * Known infection with HIV.