FLT3 mutated acute myeloid leukemia: 2021 treatment algorithm

Approximately 30% of patients with newly diagnosed acute myeloid leukemia (AML) harbor mutations in the fms-like tyrosine kinase 3 (FLT3) gene. While the adverse prognostic impact of FLT3-ITD^mut in AML has been clearly proven, the prognostic significance of FLT3-TKD^mut remains speculative. Current guidelines recommend rapid molecular testing for FLT3^mut at diagnosis and earlier incorporation of targeted agents to achieve deeper remissions and early consideration for allogeneic stem cell transplant (ASCT). Mounting evidence suggests that FLT3^mut can emerge at any timepoint in the disease spectrum emphasizing the need for repetitive mutational testing not only at diagnosis but also at each relapse. The approval of multi-kinase FLT3 inhibitor (FLT3i) midostaurin with induction therapy for newly diagnosed FLT3^mut AML, and a more specific, potent FLT3i, gilteritinib as monotherapy for relapsed/refractory (R/R) FLT3^mut AML have improved outcomes in patients with FLT3^mut AML. Nevertheless, the short duration of remission with single-agent FLT3i’s in R/R FLT3^mut AML in the absence of ASCT, limited options in patients refractory to gilteritinib therapy, and diverse primary and secondary mechanisms of resistance to different FLT3i’s remain ongoing challenges that compel the development and rapid implementation of multi-agent combinatorial or sequential therapies for FLT3^mut AML.