Relationship between morphologic remission with or without hematologic recovery and outcome after allogeneic hematopoietic cell transplantation in adult acute myeloid leukemia.

Outcomes of adults with AML after allografting vary widely. While numerous covariates have been associated with relapse, non-relapse mortality (NRM), and/or shorter survival, the impact of incomplete blood count recovery before transplantation has remained unclear. To address this uncertainty, we examined all adults with AML or MDS/AML who received an allograft in first or second remission between 2006 and 2023 at a single institution. Of 1264 patients, 891 (70%) met criteria for CR, whereas 291 (23%), 24 (2%), and 58 (5%) were classified as CRh, CRi, and morphologic leukemia-free state (MLFS), respectively. CR, CRh, CRi, and MLFS patients differed significantly regarding demographics, disease biology, pre-transplant measurable residual disease, and types of transplants. After multivariable adjustment, outcomes for CRh and CRi patients were not significantly different from each other or from those of CR patients. In contrast, outcomes of MLFS patients were substantially worse than those of CR and CRh patients, with significantly higher risk of NRM and relapse, and significantly shorter relapse-free and overall survival. Similar results were obtained in several distinct subsets. Together, our analysis provides empiric evidence for the importance of distinguishing MLFS from CR and CRh patients for optimized risk assessment and, possibly, individualized treatment decision making.