Clinical and genetic characteristics predict outcomes of acute myeloid leukemia patients with FLT3 mutations receiving venetoclax-based therapy.

ABSTRACT

BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease, and its heterogeneity is associated with treatment response. Despite the demonstrated success of venetoclax (VEN)-based therapy for AML, the effect of FLT3 mutations on the efficacy of the therapy is poorly understood. We aimed to compare the efficacy of VEN-based therapy between FLT3-mutated (FLT3mut ) and FLT3 wild-type (FLT3wt ) patients and identify the predictors of efficacy in FLT3mut patients. METHODS: A total of 266 AML patients (127 newly diagnosed [ND] and 139 refractory/relapsed [R/R]) receiving VEN-based regimens were enrolled in this study. A retrospective analysis was performed, and the treatment responses and overall survival (OS) of FLT3mut and FLT3wt patients were compared. Logistic regression and Cox proportional hazards model were applied to examine the clinical and genetic predictors of outcomes. RESULTS: With a median of two cycles of VEN-based therapy, for the ND AML cohort, the FLT3mut group had a comparable composite complete remission (CRc) rate with the FLT3wt group (79.3% vs. 61.2%, p = 0.072). For the R/R AML cohort, the FLT3mut group exhibited a lower CRc rate than the FLT3wt group. With a median follow-up of 8.6 months (95% confidence interval [CI], 8.0-10), the median OS observed in the FLT3mut and FLT3wt groups for both cohorts were close (14.0 vs. 19.9 months, p = 0.356; 10.0 vs. 11.9 months, p = 0.680). For the ND AML cohort, in FLT3mut patients, MRD-positive and RNA-splicing mutation predicted inferior survival (hazard ratio [HR], 10.3; 95% CI 2.0-53.8; p = 0.006; HR 11.3; 95% CI 1.2-109.3; p = 0.036, respectively). For the R/R AML cohort, in FLT3mut patients, adverse ELN risk was associated with an inferior response (odds ratio [OR], 0.2; 95% CI 0.1-0.8; p = 0.025), whereas NPM1 co-mutation was associated with a superior response (57.1%; OR, 6.7; 95% CI 1.5-30.1; p = 0.014). CR/CRi predicted a better survival (HR 0.2; 95% CI 0.1-0.8; p = 0.029), while DNMT3A mutation predicted an inferior survival (HR, 4.6; 95% CI 1.4-14.9; p = 0.011). CONCLUSIONS: FLT3 mutations may influence response to VEN-based therapy in R/R AML patients but not in ND AML patients. Furthermore, clinical and genetic characteristics could predict outcomes of FLT3mut patients receiving VEN-based therapy.