A Phase I Trial of Myeloablative Conditioning w/ Clofarabine and HD Busulfan for Pts w/ Refractory Heme Malignancies Undergoing Allo PBSCT

Inclusion Criteria: * Documentation of disease. Patients must have one of the following disease types: * Acute myeloid leukemia (AML) with either: * Primary refractory to induction chemotherapy * Relapsed and refractory AML with \>5% blasts in bone marrow or extramedullary disease (excluding active disease of the central nervous system). * Patients in second or subsequent complete remission (CR2, CR3, etc.). * Acute lymphoblastic leukemia (ALL) with one of the following criteria: * Primary refractory to induction chemotherapy. * Relapsed and refractory ALL with \>5% blasts in bone marrow or extramedullary disease (excluding active disease of the central nervous system). * Patients in second or subsequent complete remission (CR2, CR3, etc.). * Myelodysplasia, refractory anemia with excess blasts with 11-20% blasts in the bone marrow (RAEB II). * Chronic myelogenous leukemia (CML) with one of the following criteria: * Accelerated phase. * Patients in blast crisis. * Patients with aggressive non-Hodgkin's lymphoma (NHL), including diffuse large cell lymphoma, mediastinal B-cell lymphoma, transformed lymphoma, mantle cell lymphoma, and peripheral T cell lymphoma, who also have one of the following criteria: * Failure to achieve complete remission to primary induction therapy * Relapsed NHL, refractory to at least one line of salvage systemic therapy * Patients who relapse \< 6 months following autologous stem cell transplant…