HLA-haploidentical vs matched-sibling hematopoietic cell transplantation: a systematic review and meta-analysis

HLA haploidentical hematopoietic cell transplantation (haplo-HCT) using posttransplantation cyclophosphamide (PT-Cy) is an alternative strategy when a matched sibling donor (MSD) is not available. We performed a systematic review and meta-analysis to compare the outcomes of MSD vs haplo-HCT. Eleven studies (1410 haplo-HCT and 6396 MSD recipients) were meta-analyzed. All studies were retrospective and high quality, and 9 were multicenter. Haplo-HCT was associated with ~50% lower risk of chronic graft-versus-host disease (GVHD) (hazard ratio [HR], 0.55; 95% confidence interval [CI], 0.41-0.74), but higher risk of nonrelapse mortality (HR, 1.36; 95% CI, 1.12-1.66). Relapse, survival, acute GVHD, and GVHD-free relapse-free survival were not significantly different between the groups. Deciphering the relative contribution of PT-Cy and HLA disparity to the observed outcome differences between the groups requires further research.