FLT3 and acute myeloid leukemia: Structure-activity relationship (SAR) exploration in this series led to the identification of BPR1K871 with potent dual enzymatic (AURKA IC50 = 22 nM; AURKB = 13 nM; FLT3 IC50 = 19 nM) and cellular activities in AML cell lines (MOLM-13 and MV4-11; EC50 ∼ 5 nM).