Avapritinib is a small molecule kinase inhibitor that potently inhibits PDGFRα D842V mutant activity in vitro (IC50 = 0.5 nM) and PDGFRα D842V autophosphorylation in the cellular setting (IC50 = 30 nM); also a potent inhibitor of the analogous Kit (c-Kit) mutation, D816V in Kit (c-Kit) Exon 17 (IC50 = 0.5 nM).