AZD3229 is a potent, pan-Kit (c-Kit) mutant inhibitor with potent single digit nM growth inhibition against a diverse panel of mutant Kit (c-Kit) driven Ba/F3 cell lines (GI50=1-50 nM), with good margin to KDR-driven effects. It also inhibits PDGFR mutants (Tel-PDGFRα, Tel-PDGFRβ, V561D/D842V).