1. Patients must have relapsed/refractory leukemias for which no standard therapies are anticipated to result in a durable remission. Patients with poor-risk myelodysplasia (MDS) [i.e. IPSS ≥ 1.5 or chronic myelomonocytic leukemia (CMML) are also candidates for this protocol. Relapsed/refractory leukemias include acute non-lymphocytic leukemia (AML) by WHO classification, acute lymphocytic leukemia (ALL), chronic lymphocytic leukemia (CLL), or chronic myelogenous leukemia (CML) in blast crisis. Patients with agnogenic myeloid metaplasia (AMM) are also eligible.