Effect of Somatic Variants Post Allogeneic Hematopoietic Cell Transplantation in Acute Myeloid Leukemia and Myelodysplastic Syndrome.

Measurable residual disease (MRD) has established prognostic significance in patients with myeloid disorders; however, there is limited data regarding its prognostic and predictive value and the optimal technique for measurement in the setting of post allogeneic hematopoietic cell transplantation (allo-HCT). A multi-gene next generation sequencing (NGS) panel can overcome the limitations of conventional techniques for measurement of MRD and can shed light onto the longitudinal evolution and genomic complexity of patients undergoing allo-HCT for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). In this study, patients with AML or MDS who underwent their first allo-HCT and completed NGS testing at day +100 and were in a state of morphological remission were identified from the transplant registry of Mayo Clinic in Florida. The primary aim was to evaluate the prognostic impact of somatic variants detected via NGS at day +100 post allo-HCT on long-term outcomes. In total, 105 patients who underwent allo-HCT for AML and MDS and completed NGS testing on day +100 were included in the study population. Seventeen patients were found to have detectable variants, and 88 patients were without a detectable variant. At a median follow up of 1.4 years (0.1-5.5), presence of any variant at day +100 was associated with inferior 4-year overall survival (OS) (32% vs. 69%, P < 0.001), decreased progression free survival (PFS) (34% vs. 61%, P < 0.001), and a higher incidence of relapse (64% vs. 23%, P < 0.001). In univariate models, a lower Karnofsky performance score and presence of variants post allo-HCT remained significantly associated with inferior OS, higher relapse incidence, and a decreased PFS. The presence of variants at day +100 post allo-HCT remained significant in multivariate models for relapse ( P  = 0.002) but not for OS ( P  = 0.06) and PFS ( P  = 0.08). These results indicate that the presence of detectable somatic variants at day +100 is associated with poor long-term outcomes and are predictive of a higher incidence of relapse.