KDM6A Variants Increased Relapse Risk in Adult Acute Myeloid Leukemia.

Background/Objectives: The role of KDM6A gene mutations in acute myeloid leukemia (AML) remains poorly understood. This study aimed to evaluate the impact of KDM6A mutations on relapse risk, cumulative incidence of relapse (CIR), relapse-free survival (RFS), and overall survival (OS) in adult AML patients, with a particular focus on those with RUNX1::RUNX1T1 fusion. Methods: the retrospective analysis was conducted on 1970 adult AML patients treated at Peking University People's Hospital. Of these, 1676 patients who achieved complete remission (CR) were included. Among them, 27 harbored KDM6A mutations. Propensity score matching (PSM) was used (1:10 ratio) to compare outcomes between patients with and without KDM6A mutations. Further analysis focused on 207 patients with RUNX1::RUNX1T1 fusion, among whom 13 had KDM6A mutations (PSM 1:5). Results: In the overall cohort, KDM6A variants (n = 27) had a higher 2-year CIR (45.7% vs. 28.6%, p = 0.04). Fine-Gray analysis showed KDM6A variants independently increased relapse risk (HR = 1.98 [1.08-3.63], p = 0.03). KDM6A mutations were associated with inferior 2-year RFS (36.3% vs. 60.9%, p = 0.044). Multivariable analysis confirmed KDM6A mutations as independent predictors of poor RFS (HR = 3.08 [1.56-6.08], p = 0.001). Among RUNX1::RUNX1T1 patients, KDM6A mutations significantly increased relapse risk (75.0% vs. 21.7%, p < 0.001), raised 2-year CIR (46.9% vs. 24.0%, p = 0.05), worsened 2-year RFS (31.3% vs. 71.9%, p < 0.001), and lowered 2-year OS (63.3% vs. 86.4%, p = 0.002). They were also independent predictors of CIR (HR = 2.46 [1.11-5.47], p = 0.03), RFS (HR = 5.1, [2.5-10.5], p < 0.001) and OS (HR = 12.9, [4.3-38.7], p < 0.001). Conclusions: KDM6A mutations are significantly associated with increased relapse risk and poor prognosis in AML, especially in patients with RUNX1::RUNX1T1 fusion, and may serve as a valuable prognostic biomarker.