FLT3 and acute myeloid leukemia: Using concentrations far below the clinically achievable plasma levels, Smith et al. were unable to identify any single TKD mutation able to confer resistance to crenolanib.95 In a phase II study of 38 patients with FLT3-mutated AML (including relapsed and refractory patients), crenolanib administered at doses of 200 mg/m2 per day three times a day in 28 days cycle achieved a median EFS and OS of 8 and 19 weeks, respectively.96 Crenolanib is currently being studied in multiple clinical trials in AML patients, both with and without FLT3-mutated AMLs.