Lower dose of antithymocyte globulin does not increase graft-versus-host disease in patients undergoing reduced-intensity conditioning allogeneic hematopoietic stem cell transplant.

Salem G, Ruppert AS, Elder P, Hofmeister CC, Benson DM, Penza S, Andritsos L, Klisovic R, Vasu S, Blum W, Devine SM, Jaglowski S, Efebera YA
Leuk Lymphoma 56 1058-65 04/01/2015


The appropriate dose of antithymocyte globulin (ATG) to be utilized in reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplant (alloHSCT) is as yet unknown. We retrospectively compared patients who received 7.5 mg/kg (R-ATG, 39 patients) and 6 mg/kg (r-ATG, 97 patients). The cumulative incidences of acute graft-versus-host disease (aGVHD) grade II-IV at 180 days were 46% and 41% and of aGVHD grade III-IV were 11% and 18% in r-ATG and R-ATG, respectively (p > 0.30). The respective estimated cumulative incidences at 24 months of cGVHD were 42% and 44% (p > 0.30). There was no significant difference in non-relapse mortality (p = 0.22), cumulative incidence of relapse (p = 0.53), progression-free survival (p = 0.69) or overall survival (p = 0.95). In conclusion, a decreased ATG dose of 6 mg/kg was associated with a similar proportion of GVHD to 7.5 mg/kg ATG. Given the increasing number of RIC HSCTs performed worldwide, the correct dose and preparation of ATG should be defined by prospective randomized trials.

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