Outcomes following HSCT using fludarabine replacing cyclophosphamide as a new preconditioning regimen for treatment of hematologic malignancies

Objective To evaluate the hypothesis of fludarabine replacing cyclophosphamide as a new myeloablative preconditioning for the treatment of malignant hematologic diseases in aged and/or intolerable patients receiving allogeniec stem cell transplantation (allo-HSCT). Methods Between January 2008 and November 2008,12 patients, who were intolerant to standard conditioning regimen, received allo-HSCT with HLA identical sibling (n = 9) or mismatched family donors (n = 3),including 1 case of acute lymphoblastic leukemia with Ph chromosome (Ph+ ALL) ,6 cases of acute myelogenous leukemia (AMD,3 cases of myelodysplastic syndrome-refractory anemia with excess blasts (MDS-RAEB) and 2 cases of chronic myelogenous leukemia (CML). Stem cell sources were G-CSF mobilized peripheral blood alone (n = 1) ,or with G-CSF mobilized bone marrow (n - 11), with a median of 6. 68 (4. 35 - 7. 86) × 10~8/kg MNC and 1. 50 (0. 31 - 3. 91) × 10~6/kg CD34~+ cells. Eleven patients received revised busulfan and fludarabine regimen with/without antithymocyteglobulin(ATG),and the rest one received TBI and fludarabine regimen. GVHD prophylaxis included cyclosporin A, mycophenolate mofetil and methotrexate. Results Results All patients were well tolerated to the regimen without serious regimen related toxicity. The median time of ANC≥0. 5 × 10~9/L was day 17. 5 (11 - 23), and that of BPC≥20. 0 ×10~9/L was day 14. All patients except one got donor engraftment successfully and attained CR. With a median follow-up of 418 (62-554) days, 10 of 12 patients were alive and disease-free. Conclusion Fludarabine replacing cyclophosphamide as a new preconditioning regimen is well tolerated and safe for allo-HSCT, especially in older patients or/and those with severe concurrent medical conditions. Key words: Hematopoietic stem cell transplantation, allogeneic;  Transplantation conditioning; Fludarabine