[Improved outcome by optimized conditioning regimens with an increased dose of cyclophosphamide in allogeneic peripheral blood stem cell transplantation for severe aplastic anemia]

Objective: To respectively analyze the impact of conditioning regimens with a dose-decreased cyclophosphamide (Cy) on the outcome in fully matched sibling donor (MSD) peripheral blood stem cell transplantation (PBSCT) for severe aplastic anemia (SAA) . Methods: Two conditioning regimens with different doses of Cy (150 mg/kg or 120 mg/kg) in combination with fludarabine (Flu) and antithymocyte globulin (ATG) for MSD-PBSCT were investigated in 51 patients with acquired SAA. Results: Overall survival and failure-free survival in patients received 150 mg/kg of Cy (Cy150 cohort) or 120 mg/kg (Cy120 cohort) were 93.5% vs 90.0% (χ(2)=0.170, P=0.680) and 90.3% vs 85.0% (χ(2)=0.285, P= 0.594) respectively. However, either acute or chronic graft-versus-host disease risks were higher in Cy120 cohort than in Cy150 cohort (HR=3.89, 95% CI 1.21-12.53, P=0.023; HR=4.48, 95% CI 1.40-14.32, P= 0.011, respectively) . No difference was found for opportunistic infections or graft failure between two cohorts. Conclusion: Cy at a dose of 150 mg/kg, in combination with Flu and ATG, was more effective than that of 120 mg/kg Cy to produce improved clinical outcome in the setting of acquired SAA patients after MSD-PBSCT.