{"entity":{"id":"egfr-exon-19-deletion","kind":"biomarker","name":"EGFR exon 19 deletion","aka":["EGFR ex19del","exon 19 deletion","EGFR del19","E746_A750del","EGFR exon 19 del","classical EGFR mutation"],"tldr":"An exon 19 deletion removes a few amino acids from the EGFR kinase and leaves it switched on. With L858R it makes up about 85 percent of EGFR-mutant lung cancer and is the classic gate for osimertinib and the other EGFR inhibitors.","summary":"In-frame deletions in exon 19 (most often E746_A750del) are the commonest sensitising EGFR mutation in lung adenocarcinoma. Every EGFR tyrosine kinase inhibitor label (osimertinib, erlotinib, gefitinib, afatinib, dacomitinib, and amivantamab with lazertinib) names 'exon 19 deletions or exon 21 L858R substitution mutations' detected by an FDA-approved test; osimertinib is also labelled as adjuvant therapy after resection and with chemoradiation in stage III disease. The cobas EGFR Mutation Test v2 (tissue and plasma), therascreen EGFR RGQ PCR, Oncomine Dx Target Test, FoundationOne CDx and Liquid CDx and Guardant360 CDx are companion diagnostics; the FDA list groups the TKIs under one device indication. Exon 19 deletions respond somewhat better to TKIs than L858R in the pooled trial data.","asOf":"2026-09-23","links":[{"label":"TAGRISSO prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5e81b4a7-b971-45e1-9c31-29cea8c87ce7"},{"label":"Rybrevant prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1466c070-9f97-4fa4-a955-6a6b59981fb8"}],"tags":["biomarker","egfr"],"related":["egfr-l858r","egfr-t790m","egfr-exon-20-insertion"],"cancers":["nsclc"],"sections":[],"technologies":[],"targets":[],"drugs":["osimertinib","erlotinib","gefitinib","afatinib","dacomitinib","amivantamab","lazertinib","cobas-egfr-mutation-test","therascreen-cdx","oncomine-dx-target-test","foundationone-cdx","guardant360-cdx"],"companies":[],"institutions":[],"pathways":[],"terms":["egfr-exon19-l858r","egfr-mutation-subtypes","ngs"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"target":"egfr","measurement":"sequencing-variant","scoringRule":{"text":"An in-frame deletion within exon 19 of EGFR detected by PCR or sequencing of tumour tissue, or of plasma cell-free DNA with tissue testing if plasma is negative.","quote":"Exon 19 deletion or exon 21 L858R substitution mutation","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":"EGFR exon 19 deletion or exon 21 L858R","drugId":"osimertinib","cancerId":"nsclc","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=5e81b4a7-b971-45e1-9c31-29cea8c87ce7","quote":"adjuvant therapy after tumor resection in adult patients with non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 L858R mutations, as detected by an FDA-approved test.","status":"current"},{"value":"EGFR exon 19 deletion or exon 21 L858R","drugId":"amivantamab","cancerId":"nsclc","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1466c070-9f97-4fa4-a955-6a6b59981fb8","quote":"in combination with lazertinib for the first-line treatment of adult patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 L858R substitution mutations, as detected by an FDA-approved test.","status":"current"},{"value":"EGFR exon 19 deletion or exon 21 L858R","drugId":"gefitinib","cancerId":"nsclc","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=827d60e8-7e07-41b7-c28b-49ef1c4a5a41","quote":"IRESSA is indicated for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test","status":"current"},{"value":"EGFR exon 19 deletion or exon 21 L858R","drugId":"dacomitinib","cancerId":"nsclc","regulator":"FDA","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4ab27d2f-e385-4e9c-b324-fa69c10b855a","quote":"VIZIMPRO is indicated for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 19 deletion or exon 21 L858R substitution mutations as detected by an FDA-approved test","status":"current"}],"tests":["foundationone-cdx","foundationone-liquid-cdx","guardant360-cdx","tempus-xt","trusight-oncology-comprehensive","caris-mi-cancer-seek"],"assays":["egfr-cobas-v2","egfr-therascreen","oncomine-dx","foundationone-cdx-panel","guardant360-cdx"],"companionDiagnostics":[{"device":"cobas EGFR Mutation Test v2","maker":"Roche Molecular Systems","drugs":["osimertinib","erlotinib","gefitinib","afatinib"],"indication":"Non-Small Cell Lung Cancer (NSCLC) - Tissue or Plasma","pma":"P120019/S031 (10/27/2020)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"therascreen EGFR RGQ PCR Kit","maker":"QIAGEN Manchester","companyId":"qiagen","drugs":["afatinib"],"indication":"Non-Small Cell Lung Cancer (NSCLC) - Tissue","pma":"P120022 (07/12/2013)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"therascreen EGFR RGQ PCR Kit","maker":"QIAGEN Manchester","companyId":"qiagen","drugs":["dacomitinib"],"indication":"Non-Small Cell Lung Cancer (NSCLC) - Tissue","pma":"P120022/S018 (09/27/2018)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"FoundationOne CDx","maker":"Foundation Medicine","companyId":"foundation-medicine","drugs":["osimertinib","erlotinib","gefitinib","afatinib"],"indication":"Non-Small Cell Lung Cancer (NSCLC) - Tissue","pma":"P170019 (11/30/2017)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"Guardant360 CDx","maker":"Guardant Health","companyId":"guardant-health","drugs":["osimertinib"],"indication":"Non-Small Cell Lung Cancer (NSCLC) - Plasma","pma":"P200010 (08/07/2020)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"},{"device":"Oncomine Dx Target Test","maker":"Life Technologies (Thermo Fisher Scientific)","companyId":"thermo-fisher","drugs":["gefitinib"],"indication":"Non-Small Cell Lung Cancer (NSCLC) - Tissue","pma":"P160045 (06/22/2017)","source":"https://www.fda.gov/medical-devices/in-vitro-diagnostics/list-cleared-or-approved-companion-diagnostic-devices-in-vitro-and-imaging-tools"}],"forPatient":"An exon 19 deletion means an EGFR tablet, most often osimertinib, or amivantamab with lazertinib, is the first treatment for advanced lung cancer rather than chemotherapy or immunotherapy; after surgery, osimertinib for three years is also on label. Immunotherapy alone does not work well against these tumours, so the labels for PD-1 drugs exclude them."},"route":"/biomarkers/egfr-exon-19-deletion/","neighbours":{"biomarker":[{"id":"egfr-exon-20-insertion","kind":"biomarker","name":"EGFR exon 20 insertion","route":"/biomarkers/egfr-exon-20-insertion/"},{"id":"egfr-l858r","kind":"biomarker","name":"EGFR L858R","route":"/biomarkers/egfr-l858r/"},{"id":"egfr-t790m","kind":"biomarker","name":"EGFR T790M","route":"/biomarkers/egfr-t790m/"},{"id":"her3-expression","kind":"biomarker","name":"HER3 expression","route":"/biomarkers/her3-expression/"}],"cancer":[{"id":"nsclc","kind":"cancer","name":"Non-small-cell lung cancer","route":"/cancers/nsclc/"}],"drug":[{"id":"afatinib","kind":"drug","name":"Afatinib","route":"/drugs/afatinib/"},{"id":"amivantamab","kind":"drug","name":"Amivantamab","route":"/drugs/amivantamab/"},{"id":"cobas-egfr-mutation-test","kind":"drug","name":"cobas EGFR Mutation Test v2","route":"/drugs/cobas-egfr-mutation-test/"},{"id":"dacomitinib","kind":"drug","name":"Dacomitinib","route":"/drugs/dacomitinib/"},{"id":"erlotinib","kind":"drug","name":"Erlotinib","route":"/drugs/erlotinib/"},{"id":"foundationone-cdx","kind":"drug","name":"FoundationOne CDx / Liquid CDx","route":"/drugs/foundationone-cdx/"},{"id":"gefitinib","kind":"drug","name":"Gefitinib","route":"/drugs/gefitinib/"},{"id":"guardant360-cdx","kind":"drug","name":"Guardant360 CDx","route":"/drugs/guardant360-cdx/"},{"id":"lazertinib","kind":"drug","name":"Lazertinib","route":"/drugs/lazertinib/"},{"id":"oncomine-dx-target-test","kind":"drug","name":"Oncomine Dx Target Test","route":"/drugs/oncomine-dx-target-test/"},{"id":"osimertinib","kind":"drug","name":"Osimertinib","route":"/drugs/osimertinib/"},{"id":"therascreen-cdx","kind":"drug","name":"therascreen companion diagnostic kits (KRAS, EGFR, PIK3CA, FGFR, BRAF)","route":"/drugs/therascreen-cdx/"}],"term":[{"id":"egfr-exon19-l858r","kind":"term","name":"EGFR exon 19 deletion & L858R","route":"/terms/egfr-exon19-l858r/"},{"id":"egfr-mutation-subtypes","kind":"term","name":"EGFR mutation subtypes (exon 19 deletion, L858R, exon 20 insertion, T790M)","route":"/terms/egfr-mutation-subtypes/"},{"id":"ngs","kind":"term","name":"Next-generation sequencing (NGS)","route":"/terms/ngs/"}],"target":[{"id":"egfr","kind":"target","name":"EGFR","route":"/targets/egfr/"}]}}