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.