Fludarabine plus busulfan conditioning regimen for allogeneic hematopoietic stem cell transplantation in treating leukemia patients

Objective To explore the clinical efficacy of fludarabine plus busulfan conditioning regimen for allogeneic hematopoietic stem cell transplantation(allo-HSCT) in treating leukemia patients.Methods Of the 6 patients,2 had chronic myelogenous leukemia in their chronic phase,2 had acute lymphoid leukemia,1 had acute myeloid leukemia and 1 had acute myeloid leukemia transformed from myelodysplastic syndrome(MDS).The conditioning regimen included fludarabine 30mg/m2·d for 4 days,intravenous injection of busulfan 3.2mg/kg·d for 2 to 4 days,and rabbit anti-human thymocyte globulin 2.5mg/kg·d for 3 days in patients with unrelated donor.The number of infused peripheral blood stem cells was 3.0-8.03×106 CD34+ cells/kg(average of 4.29×106/kg) and that of peripheral blood mononuclear cells was 6.74-13.51×108 cells/kg(average of 9.01×108/kg).Cyclosporine and short-term methotrexate were used to prevent graft-versus-host disease.Results No severe regimen-related toxicity occurred in any of the patients.Five patients achieved hematopoiesis recomstruction with their full donor chimerisms confirmed by STR-DNA analysis.The other one had leukemia relapse within one month after HSCT.Except the early-relapsing patient who died later,the other 5 patients remained alive without relapse in the follow-up duration of 8 to 20 months(median of 10 months).Conclusion The conditioning regimen with fludarabine plus busulfan is safe and effective in treating patients with hematopoietic malignant diseases with fewer complications.The long-term efficacy needs further evaluation.