KIT and gastrointestinal stromal tumor: Avapritinib, an oral, selective KIT and PDGFRA inhibitor, readily fits into the ATP binding pocket, with the activation loop in an open, aspartate (D)-phenylalanine (F)-glycine (G) motif (DFG)-in conformation23,31,60 In a phase I study, avapritinib was found to be active in patients with PDGFRA D842V mutant GIST with an ORR of 88%.32,62 This study led to FDA and European Medicines Agency approvals in 2020 use in GIST with PDGFRA exon 18 and with PDGFRA D842V mutations, respectively.57,58