The Optimization of Conditioning Regimen for HLA Matched HSCT in SAA

Hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen (HLA) -matched donor is an effective option for severe aplastic anemia (SAA), but there is no standardized and recommended conditioning regimen. The occurrence of mixed chimerism after transplantation is associated with secondary graft failure and poor failure-free survival. Previous studies have shown that Fludarabine (Flu)/ Cyclophosphamide (Cy)/ antithymocyte globulin (antithymocyte globulin), ATG) and Cy/ATG conditioning regimens had higher rates of mixed chimerism and poorer failure-free survival. A small cohort study has suggested that adding busulfan to Flu/Cy/ATG or Cy/ATG can reduce the incidence of mixed chimerism and improve failure-free survival. This study was a prospective, multicenter, randomized controlled trial to compare the efficacy and safety of different conditioning regimens in the treatment of severe aplastic anemia (SAA) after hematopoietic stem cell transplantation (HSCT) from HLA-identical sibling or unrelated donor.