Ex Vivo Expansion of Mafosfamide Purged CD34+ Cells in Patients With Acute Leukemia

Overview

RATIONALE: Giving colony-stimulating factors, such as G-CSF, and certain chemotherapy drugs, helps stem cells move from the bone marrow to the blood so they can be collected. Treating stem cells collected from the patient's blood or bone marrow with chemotherapy in the laboratory removes any remaining cancer cells. Chemotherapy or radiation therapy is given to the patient to prepare the bone marrow for stem cell transplant. The treated stem cells are then returned to the patient to replace the blood-forming cells that were destroyed by the chemotherapy. PURPOSE: This clinical trial is studying how well an autologous peripheral stem cell or bone marrow transplant using laboratory-treated cells works in treating patients with acute leukemia.

OBJECTIVES: * Determine the feasibility of ex vivo expanded mafosfamide-purged CD34-positive cells for autologous peripheral blood stem cell or bone marrow transplantation in patients with acute leukemia. * Determine the duration of aplasia associated with the use of ex vivo cytokine expanded mafosfamide-purged cells in patients treated with this regimen. * Determine, preliminarily, the event-free survival of patients treated with this regimen. OUTLINE: This is a pilot study. * Mobilization and stem cell collection: Patients receive cyclophosphamide IV and filgrastim (G-CSF) subcutaneously (SC) or IV once daily for 7-14 days followed by leukapheresis to collect peripheral blood stem cells (PBSCs). Some patients may also undergo bone marrow (BM) harvest if sufficient PBSCs are not collected. Patients with a sufficient number of stem cells or BM (5 x 10\^6 PBSC/kg or 3 x 10\^8 BM cells/kg) proceed to autologous PBSC transplantation (PBSCT) or BM transplantation (BMT). * CD34-positive cell selection and mafosfamide purging: Collected PBSCs and/or BM are treated in the laboratory to isolate CD34-positive cells. A minimum of 1 x 10\^6 nucleated CD34-positive BM cells/kg or 2 x 10\^6 nucleated CD34-positive PBSCs/kg must be available after selection to proceed to mafosfamide-purging. The selected cells are then treated in vitro with mafosfamide to purge remaining leukemic cells. One third of the mafosfamide-purged cells are then cryopreserved for future use and 2/3 of the mafosfamide-purged cells proceed to ex vivo expansion. * Ex vivo expansion: The remaining CD34-positive mafosfamide-purged cells are treated in vitro with stem cell factor, G-CSF, and recombinant human thrombopoietin and incubated for 12-14 days. * Myeloablative therapy: Patients receive busulfan on days -9 to -6 and cyclophosphamide on days -5 to -2. * PBSCT or BMT: Patients undergo autologous PBSCT or BMT using CD34-positive mafosfamide-purged cryopreserved cells and ex vivo expanded CD34-positive mafosfamide-purged cells on day 0 followed by G-CSF SC or IV once daily until blood counts recover. After completion of study treatment, patients are followed periodically for at least 5 years. PROJECTED ACCRUAL: A total of 25 patients will be accrued for this study.