FLT3 and leukemia: BDT001 inhibited FL-induced FLT3 phosphorylation in leukemia-derived RS4–11 cells, also measured by trFRET (see Supplementary Fig. 7a, b for phosphorylation assay validation) with an IC50 of 18–24 μM that was almost unchanged with increasing FL concentrations (Fig. 6g).