The Optimization of Conditioning Regimen for HLA Matched HSCT in SAA

To Evaluate Different Conditioning Regimens for HLA Matched Donor Transplantation in Severe Aplastic Anemia: a Prospective, Multicenter, Randomized Controlled Study

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.

The conditioning regimens were Bu/Flu/Cy/ATG or Bu/Cy/ATG, depending on the patient's risk factors of regimen related cardiotoxicity.

The conditioning regimens were Flu/Cy/ATG or Cy/ATG, depending on the patient's risk factors of regimen related cardiotoxicity.

Conditioning regimens were Bu/Flu/Cy/ATG or Bu/Cy/ATG, depending on the patient's risk factors of regimen related cardiotoxicity.

Conditioning regimens were Flu/Cy/ATG or Cy/ATG, depending on the patient's risk factors of regimen related cardiotoxicity.

Inclusion Criteria: Diagnosed as SAA/vSAA Indication for hematopoietic stem cell transplantation Available HLA matched sibling or unrelated donor No active infection No serious organ damage: liver and kidney function (ALT and AST < 2.5 times normal value, normal renal function, no cardiac insufficiency) Signed informed consent High risk factors of mixed chimerism, at least one of the following Age < 18 years old Ferritin level ≥2500ng/ml before transplantation Exclusion Criteria: Age > 50 years old ECOG≥3 Active infections that were difficult to control Severe liver and kidney dysfunction Mental illness Not signing the informed consent pregnant or lactating women Any condition considered by the investigators to be unsuitable for enrollment