FLT3 and acute myeloid leukemia: In FLT3-mutated AML patients, first-generation TKI monotherapy produced suboptimal results in the relapsed/refractory setting; however, more potent second-generation TKIs demonstrated significant activity as single agents, and some of these agents like gilteritinib have shifted the treatment options toward chemotherapy-free approach for relapsed/refractory FLT-3-mutated AML patients [20-22].