Role Of Antithymocyte Globulin In Matched Sibling Donor Peripheral Blood Stem Cell Transplantation For Hematologic Malignancies

Background: High incidence of chronic graft-versus-host disease (GVHD) has been a major drawback of matched sibling donor peripheral blood stem cell transplantation (MSD-PBSCT). This study aimed to investigate the safety and efficacy of antithymocyte globulin (ATG) as a standardized part of GVHD prophylaxis in patients receiving MSD-PBSCT.Methods: A total of 72 patients with hematological malignancies receiving MSD-PBSCT who displayed similar baseline characteristics were either given rabbit ATG (n=42) or no ATG (n=30), in addition to cyclosporine, methotrexate, and mycophenolate mofetil as a standard GVHD prophylaxis regimen. Either patients or donors aged >= 40years were included in the study. Thymoglobulin was administered at a daily dose of 1.5mg/kg on day-5 and 3.5mg/kg on day-4 prior to transplant (the total dose was 5mg/kg)Results: After a median follow-up of 874days, the 3-year cumulative incidence of chronic GVHD (cGVHD) was 37.3% in the ATG group and 52.1% in the non-ATG group. The 3-year overall and disease-free survival probability were 71.0% and 62.0% (ATG versus non-ATG, P=.262) and 66.7% and 58.4% (ATG versus non-ATG, P=.334). No difference was found in the 2-year cumulative incidence of nonrelapse mortality and relapse between the ATG and non -ATG groups. This significant reduction in the incidence of cGVHD without increased relapse risk and nonrelapse mortality led to a 3-year GVHD-free, relapse-free survival probability of 66.7% and 40.0% in the ATG and non-ATG groups, respectively.Conclusions: These data suggested that rabbit antithymocyte globulin in the current protocol for GVHD prophylaxis was well tolerable and efficacious.