Combination of Anti-thymocyte Globulin with Post-transplant Cyclophosphamide for GVHD Prophylaxis in Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplantation: Systematic Review and Meta-analysis.

A new strategy combining anti-thymocyte globulin with post-transplant cyclophosphamide (ATG/PTCy) for graft-versus-host disease (GVHD) prevention was developed. This study aims to perform a systematic review and meta-analysis of studies comparing ATG/PTCy with ATG or PTCy in patients with hematological malignancies undergoing haploidentical hematopoietic stem cell transplantation. Meta-analysis was conducted with Review Manager version 5.4; pooled risk ratios (RRs) and hazard ratios (HRs) were calculated for dichotomous data and time-to-event data, respectively. A fixed-effects model was used if there was no significant heterogeneity. Literature search and study selection identified 14 eligible studies, including both randomized controlled trial and retrospective comparative studies. Different dosage adjustment strategies were applied; the total dose was 2.5-10 mg/kg for ATG and 29-100 mg/kg for PTCy. Meta-analysis results suggest that ATG/PTCy is associated with significantly lower risk of grades II-IV acute GVHD compared with ATG (RR 0.52; 95% CI: 0.41-0.65; P < .00001) and PTCy (RR 0.53; 95% CI: 0.34-0.83; P = .005) without increasing risk of disease relapse. In addition, ATG/PTCy is associated with significantly better overall survival and GVHD-free/relapse-free survival than ATG and PTCy. Future research is required to further establish the benefits of ATG/PTCy and determine the optimal dosage adjustment strategies.