MK0457 in Patients With Leukemia (0457-003)

Inclusion Criteria: Part 1: * Patients with relapsed/refractory acute myelogenous leukemia (AML), poor risk myelodysplastic syndrome (MDS), B-cell acute lymphocytic leukemia (ALL), myeloproliferative diseases, or chronic myelogenous leukemia (CML) in blast crisis Part 2: * Acute myelogenous leukemia (with FLT-3 mutation ), and myeloproliferative diseases only * At least 2 weeks since the last cytotoxic therapy * Acceptable renal and hepatic function * Ambulatory, capable of all self-care, and out of bed for more than 50% of waking hours * More than 2 months since autologous bone marrow or peripheral blood stem cell transplantation Exclusion Criteria: * Not fully recovered from previous anti-leukemia therapy * Previous allogeneic bone marrow transplant * Uncontrolled congestive heart failure * Myocardial infarction within the last 3 months * Active or uncontrolled infection * Pregnancy or lactation * Currently active second malignancy, other than non-melanoma skin cancer * History of hepatitis B or C, known HIV positivity, or AIDS related illness