FLT3 and acute myeloid leukemia: Quizartinib is metabolized to its pharmacologically active primary metabolite AC886, which has similar potency and selectivity as the parent [dissociation constant (Kd) values for FLT3 of 1.3 nM for quizartinib and 0.54 nM for AC886], with a metabolite–parent ratio of 60% following repeated daily dosing in patients with AML (data on file, Daiichi Sankyo Inc., Basking Ridge, NJ, USA).