[The efficacy and safety of modified busulfan/fludarabine conditioning regimen in elderly or drug-intolerable patients with hematologic malignancies].

Objective: To evaluate the efficacy and safety of modified busulfan (Bu, 9.6 mg/kg)/fludarabine (Flu) conditioning regimen on malignant hematologic diseases in elderly and/or drug-intolerable patients.
Methods: We utilized a new reduced intensity conditioning (RIC) containing of new dosage of intravenous Bu (9.6 mg/kg), Flu (150 mg/m(2)), cytarabine and semustine but without antithymocyte globulin (ATG) in 23 aged and/or intolerable patients with malignancies. All 23 patients, with a median age of 49 (8-66) years, received an allogeneic hematopoietic stem cell transplantation with human leukocyte antigen (HLA) identical sibling donors during January 2008 and January 2012. Stem cells were collected from granulocyte colony-stimulation factor (G-CSF) mobilized bone marrow plus G-CSF mobilized peripheral blood(G-PB) in 20 patients, G-PB alone in two, and non-mobilized BM in one. The graft had a median mononuclear cells (MNC) of 7.03 (4.04-9.9)×10(8)/kg and 1.76 (0.31-6.43)×10(6)/kg of CD(+)34 cells. Graft-versus-host disease (GVHD) prophylaxis included cyclosporin A, mycophenolate mofetil and methotrexate.
Results: All patients were well tolerated to the regimen without serious drug related toxicity. Transplant related mortality were 0 and 4.3% at day 100 and one year. All patients except one got full donor engraftment and achieved complete remission. Acute GVHD was observed in 6 patients (26.1%) including grade III-IV in 5 patients. Chronic GVHD was reported in 15 of 21 evaluable patients (71.4%). With a median follow-up of 1138 (55-1747) days, 16 of 23 patients were alive and disease-free. Three-year overall survival (OS) and event free survival (EFS) were 79.2% and 69.6%, respectively.
Conclusion: Modified Bu/Flu as a new RIC regimen is well tolerated and safe for patients who need allogeneic hematopoietic stem cell transplantation, especially in older patients and/or patients with severe comorbidities.