Multicenter cohort study of association of unrelated donor age with recipient outcomes after prosttransplant cyclophosphamide vs conventional prophylaxis

Advanced age in unrelated donors (URDs) is a risk factor in allogeneic hematopoietic cell transplant (HCT), leading registries to prioritize young donors. However, this paradigm relevance is uncertain in the era of posttransplant cyclophosphamide (PTCy) for GVHD prophylaxis. A multicenter cohort study investigated the association of URD age with overall survival of recipients who underwent HCT for AML or MDS receiving PTCy or conventional calcineurin inhibitor (CNI)-based GVHD prophylaxis. In this cohort study of 10,025 HCT recipients, increasing donor age was associated with worse overall survival in those receiving CNI-based prophylaxis. This association was substantially attenuated and not statistically significant was PTCy-based prophylaxis, a finding supported by machine learning models. The authors conclude that the negative association of older donor age with HCT survival appears mitigated with PTCy, suggesting increased flexibility for selecting older unrelated donors when PTCy is used.