KIT and gastrointestinal stromal tumor: Avapritinib (BLU-285) is a potent and selective small-molecule inhibitor that targets KIT proto-oncogene receptor tyrosine kinase (KIT) exon 17 and platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutations via type 1 inhibition.1-3 Preclinical studies demonstrated robust in vitro and in vivo activity of avapritinib against clinically relevant KIT primary and resistant mutants.4 Avapritinib was first approved in 2020 in the US for unresectable or metastatic gastrointestinal stromal tumors (GIST) with PDGFRA exon 18 mutations.