Antithymocyte globulin for acute-graft-versus-host-disease prophylaxis in patients undergoing allogeneic hematopoietic cell transplantation: a systematic review.

Graft-versus-host-disease (GVHD) is a major complication associated with allogeneic hematopoietic cell transplantation (allo-HCT). Antithymocyte globulin (ATG) is recommended for GVHD prophylaxis following allo-HCT, however, evidence on efficacy of ATG is conflicting. Accordingly, we undertook a systematic review. All phase III randomized controlled trials (RCTs) comparing ATG versus control for prevention of GVHD in patients undergoing allo-HCT were eligible. Medline and Cochrane databases were searched. Data on methodological quality, benefits and harms were extracted for each trial and pooled under a random effects model. Seven RCTs enrolling 733 patients met inclusion criteria. Pooled results showed no difference for overall survival with use of ATG (hazard ratio was 0.91; 95% confidence intervals (CI), 0.75-1.10; P = 0.32). There was a significant benefit for prevention of grade III/IV acute GVHD (risk ratio (RR) = 0.51; 95% CI, 0.27-0.94; P = 0.03). There was no benefit associated with ATG use for prevention of either grade II (RR = 0.79; 95% CI, 0.48-1.30; P = 0.35) or grade I acute GVHD (RR = 1.42; 95% CI, 0.75-2.69; P = 0.28). Use of ATG was not associated with significant reduction in non-relapse mortality (RR = 0.74; 95% CI, 0.53-1.03; P = 0.08). Future trials with adequate sample size are required to provide more definitive answers.