First-generation FLT3 TKIs, midostaurin and sorafenib, display relatively limited selectivity for FLT3 and have relatively low potency in human plasma, which is thought to underlie their modest antileukemic efficacy when used as single agents in patients with R/R FLT3-mutated AML [14, 15]. Here, FLT3 is linked to acute myeloid leukemia.