PDGFRA and gastrointestinal stromal tumor: Before the regulatory approval of avapritinib, the outcomes of patients with advanced or metastatic PDGFRA D842V-mutant GIST were dismal due to the intrinsic resistance to the TKIs commonly used in GIST therapeutics.10-13 Avapritinib, a type I TKI targeting specifically the activation loop of PDGFRA, is the first-ever treatment to show activity against this rare GIST molecular subtype.