{"entity":{"id":"pdgfra-exon-18-d842v","kind":"biomarker","name":"PDGFRA exon 18 mutation (D842V)","aka":["PDGFRA D842V","D842V","PDGFRA exon 18","PDGFRA exon 18 mutation","PDGFRA-mutant GIST"],"tldr":"PDGFRA D842V drives about 5 percent of gastrointestinal stromal tumours and is resistant to imatinib. Avapritinib is the approved drug for GISTs with PDGFRA exon 18 mutations including D842V.","summary":"Exon 18 mutations sit in the activation loop; D842V, the commonest, stabilises the active kinase and blocks imatinib, sunitinib and regorafenib binding. Avapritinib (Ayvakit, 2020) is labelled for unresectable or metastatic GIST harbouring a PDGFRA exon 18 mutation, including D842V, and the therascreen PDGFRA RGQ PCR Kit is its companion diagnostic (P210002, 2023). Non-D842V exon 18 mutations remain partly imatinib-sensitive, so the exact variant is reported.","asOf":"2026-09-23","links":[{"label":"AYVAKIT prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=645c887c-8cd4-4623-8da9-ac223d71a8b9"}],"tags":["biomarker","gist"],"related":["kit-d816v"],"cancers":["gist","gist-pdgfra-d842v"],"sections":[],"technologies":[],"targets":[],"drugs":["avapritinib","imatinib","therascreen-cdx"],"companies":[],"institutions":[],"pathways":[],"terms":["gist-risk-stratification"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"target":"pdgfra","measurement":"sequencing-variant","scoringRule":{"text":"A PDGFRA exon 18 mutation, including D842V, by the therascreen PDGFRA RGQ PCR Kit or sequencing of tumour tissue.","quote":"PDGFRA: D842V","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools","sourceLabel":"FDA: List of FDA-Authorized Companion Diagnostic Devices"},"thresholds":[{"value":"PDGFRA exon 18 mutation including D842V","drugId":"avapritinib","cancerId":"gist-pdgfra-d842v","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=645c887c-8cd4-4623-8da9-ac223d71a8b9","quote":"1.1 PDGFRA Exon 18 Mutation-Positive Unresectable or Metastatic Gastrointestinal Stromal Tumor (GIST) AYVAKIT ® is indicated for the treatment of adults with unresectable or metastatic GIST harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation, including PDGFRA D842V mutations.","status":"current"}],"tests":["foundationone-cdx","tempus-xt","caris-mi-profile"],"assays":[],"companionDiagnostics":[{"device":"therascreen PDGFRA RGQ PCR Kit","maker":"QIAGEN","companyId":"qiagen","drugs":["avapritinib"],"indication":"Gastrointestinal Stromal Tumors (GIST) - Tissue","pma":"P210002 (06/29/2023)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"}],"forPatient":"If your GIST carries a PDGFRA D842V mutation, imatinib is unlikely to work and avapritinib tablets are the on-label treatment for advanced disease. Every GIST should have KIT and PDGFRA sequenced before treatment, because the mutation decides the drug and the dose."},"route":"/biomarkers/pdgfra-exon-18-d842v/","neighbours":{"biomarker":[{"id":"kit-d816v","kind":"biomarker","name":"KIT D816V","route":"/biomarkers/kit-d816v/"}],"cancer":[{"id":"gist","kind":"cancer","name":"Gastrointestinal stromal tumour (GIST)","route":"/cancers/gist/"},{"id":"gist-pdgfra-d842v","kind":"cancer","name":"PDGFRA D842V-mutant GIST","route":"/cancers/gist-pdgfra-d842v/"}],"drug":[{"id":"avapritinib","kind":"drug","name":"Avapritinib","route":"/drugs/avapritinib/"},{"id":"imatinib","kind":"drug","name":"Imatinib","route":"/drugs/imatinib/"},{"id":"therascreen-cdx","kind":"drug","name":"therascreen companion diagnostic kits (KRAS, EGFR, PIK3CA, FGFR, BRAF)","route":"/drugs/therascreen-cdx/"}],"term":[{"id":"gist-risk-stratification","kind":"term","name":"GIST risk stratification (mitotic count, size, site; Miettinen and modified NIH criteria)","route":"/terms/gist-risk-stratification/"}],"target":[{"id":"pdgfra","kind":"target","name":"PDGFRA","route":"/targets/pdgfra/"}]}}