Comparison of Different Conditioning Regimens of Haploidentical Hematopoietic Stem Cell Transplant in Patients With Acute Myeloid Leukemia.

OBJECTIVES: We evaluated the safety and efficacy of 2 conditioning regimens (busulfan/fludarabine vs modified busulfan/cyclophosphamide) in patients with acute myeloid leukemia undergoing haploidentical hematopoietic stem cell transplant.

MATERAILS AND METHODS: Twenty patients with primary acute myeloid leukemia had been randomized into busulfan/fludarabine and modified busulfan/cyclophosphamide groups. We retrospectively compared hematopoietic engraftment, regimen-related toxicity, graft-versus-host disease, transplant-related mortality, leukemia-free survival, and overall survival between the groups.

RESULTS: All patients achieved engraftment with 100% donor chimerism. The median times for the neutrophil and platelet engraftment in the busulfan/fludarabine and modified busulfan/cyclophosphamide groups were 14.1 versus 14.3 days and 12.7 versus 12.2 days, respectively. Significantly lower incidences of pretreatment toxicity, blood transfusion, and virus activation were observed in the busulfan/fludarabine group. Acute grade 1 graft-versus-host-disease developed in all patients, which was successfully controlled with methylprednisolone. There were no significant differences in engraftment, graft-versus-host disease, leukemia-free survival, and overall survival between groups. Both of these conditioning regimens achieved stable engraftment. Regimen-related toxicity in the busulfan/fludarabine group was well tolerated compared with that in the modified busulfan/cyclophosphamide group, without an increase in relapse rate.

CONCLUSIONS: Our results demonstrated that myeloablative busulfan/fludarabine might be a highly effective and low-toxicity alternative for patients with acute myeloid leukemia.