Inclusion Criteria:

- Adult patients with advanced leukemias or myelodysplastic syndromes defined in
section 4.1; Eastern Cooperative Oncology Group performance status 0-2; adequate
hepatic and renal function; ability to swallow capsules; be at least 2 weeks from
prior chemotherapy, radiation therapy, major surgery or other investigational
anticancer therapy; and have recovered from prior toxicities.

Exclusion Criteria:

- Patients with known CNS involvement by leukemia; plan to undergo allogeneic bone
marrow transplant within 4 weeks; currently on other investigational agents;
uncontrolled intercurrent illnesses; pregnant or lactating women; known to be HIV
positive