EHA 2026 | ATG vs PTCY GVHD Prophylaxis Clinical Outcome Analysis Report

Abstract: EHA-7202 Short: LB5009 The question of whether post-transplant cyclophosphamide (PTCy) should replace anti-thymocyte globulin (ATG/ATLG) as the standard GVHD prophylaxis backbone in HLA-compatible 10/10 matched unrelated donor (MUD) hematopoietic cell transplantation (HCT) has now been directly addressed by a large, prospective randomized controlled trial presented at EHA 2026 by Prof. Johannes Schetelig (Dresden, Germany) and co-investigators including Matthias Stelljes. The trial — designated the GRAPPA study — concludes that ATG-based prophylaxis retains its standard-of-care position in this specific setting, with PTCy failing to demonstrate superiority on the primary composite endpoint. This finding is contextualized against a backdrop of registry data, meta-analyses, and prior Phase 2/3 evidence that had generated significant debate about PTCy's potential to displace ATG in the 10/10 MUD context.