The treatment of gastrointestinal stromal tumor (GIST), a rare tumor type with an estimated incidence of 3,300 to 6,000 new cases per year in the United States, has seen exciting advances this year, first with the FDA's approval of avapritinib for metastatic GIST with platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutations, and more recently with last month's approval of ripretinib for the later-line treatment of metastatic GIST. Margaret von Mehren, MD, principal investigator o...