Potent, selective inhibitor of class III receptor tyrosine kinases (IC50 values are 0.3 μM for c-Fms, c-Kit, FLT3 and ITD-FLT3 and 1 μM for PDGFRβ). Displays no selectivity for ERK1, ERK2, EGFR, MEK1, HER2, Src, Abl, PKC, PKA and Akt (IC50 > 10 μM). Inhibits FL-dependent proliferation in BaF/ITD-FLT3 cells more potently than BaF/wt-FLT3 cells; anti-leukaemic.