FLT3 and acute myeloid leukemia: Because clonal evolution in AML has recently been shown to contribute to the development of resistance to initial FLT3 TKI therapy [11, 12] and there are limited data to guide clinical use of gilteritinib in an era where patients are commonly treated with frontline TKIs, we performed a retrospective analysis of the CHRYSALIS and ADMIRAL trials to evaluate response and survival in patients with FLT3-mutated, R/R AML who received or did not receive prior TKI therapy with midostaurin or sorafenib before treatment with gilteritinib.