Post-transplant cyclophosphamide-based graft-versus-host disease prophylaxis and its impact on allogeneic hematopoietic cell transplantation donor selection: A summary of the SBTMO/ABHI joint session at the 2025 SBTMO annual meeting

This brief communication summarizes the joint session of the Brazilian Cellular Therapy and Bone Marrow Transplantation Society (SBTMO) and the Brazilian Histocompatibility and Immunogenetics Association (ABHI), held during the 2025 SBTMO Annual Meeting. The joint session focused on how post-transplant cyclophosphamide (PTCy) is redefining donor selection in contemporary allogeneic hematopoietic cell transplantation (HCT). In three lectures with experts in the field, several topics concerning PTCy were addressed, including the effectiveness of PTCy in overcoming the HLA barrier, the increased use of mismatched unrelated donors (MMUD) under PTCy, which significantly broadens HCT access for underserved ethnic minorities, and strategies for reducing the dose of PTCy. The impact of donor-specific HLA antibodies in allogeneic HCT, the importance of HLA serotypes (associated antigens) in improving the accuracy of virtual crossmatch during MMUD searches, and the utility of novel bioinformatics tools to enhance serotype evaluation for MMUD selection under PTCy were also discussed. Additionally, the present report outlines the discussions among the speakers, session chairs, and audience members.