Avapritinib for metastatic or unresectable gastrointestinal stromal tumors

Avapritinib is a tyrosine kinase inhibitor (TKI) that has recently received Food and Drug Administration (FDA) approval for the treatment of metastatic or unresectable gastrointestinal stromal tumors harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation. Mutations in the activation loop of PDGFRA or KIT confer resistance to conventional TKIs due to structural changes in the receptor. Avapritinib was developed to selectively target these mutations, thereby offering a new treatment option for patients in whom imatinib, sunitinib, and regorafenib have failed. This review covers the basic science and preclinical studies that guided avapritinib's development, in addition to the data currently available from early clinical studies as well as those later-stage trials that led to its approval.