Mutational Landscape and Clonal Dynamics in AML Undergoing PTCy Hematopoietic Cell Transplantation

To improve risk stratification, we performed targeted NGS at diagnosis in 191 patients with AML undergoing myeloablative allogeneic HCT with PTCy-based prophylaxis. We also investigated clonal evolution using paired diagnostic and relapse samples from 39 individuals. A total of 610 mutations were detected in 184 patients (96%), most commonly in FLT3 (26%), DNMT3A (25%), RUNX1 (24%), and NPM1 (19%). Sixteen unique fusion genes were identified in 35 patients, with KMT2A (43%) and core binding factor rearrangements (23%) being the most frequent. TP53 and WT1 mutations were strongly associated with adverse outcomes, whereas NPM1 retained favorable significance. RUNX1 co-mutations with SF3B1 or NRAS were associated with inferior survival. In an exploratory allelic analysis, multi-hit TP53 alterations, but not single-hit mutations, were associated with distinctly poorer OS, event-free survival (EFS), and relapse risk. Relapse involved mutational shifts in ∼70% of cases, with significant enrichment of WT1 and more modest increases in TP53, KRAS, ASXL1, NF1, and MECOM, while DNMT3A, TET2, and ASXL1 persisted stably. Neither acute nor chronic graft-versus-host disease was associated with molecular remodeling at relapse. Incorporating TP53 and WT1 into risk models, recognizing context-dependent effects of DNMT3A and RUNX1, and applying longitudinal genomic monitoring may help guide personalized strategies to prevent relapse.