Acquired EGFR C797G Mutation Detected by Liquid Biopsy as Resistance Mechanism After Treatment With Osimertinib: A Case Report

xlomafota13 shared this article with you from Inoreader Acquired EGFR C797G Mutation Detected by Liquid Biopsy as Resistance Mechanism After Treatment With Osimertinib: A Case Report Via In vivo (Athens, Greece) In Vivo. 2021 Sep-Oct;35(5):2941-2945. doi: 10.21873/invivo.12586. ABSTRACT BACKGROUND: Osimertinib is a third-generation EGFR-tyrosine kinase inhibitor approved for the treatment of T790M-positive non-small-cell lung cancer. More recently, osimertinib demonstrated improved disease control compared to other EGFR-TKIs. Multiple mechanisms of resistance have been described in T790M-positive patients who experienced treatment failure with osimertinib. CASE REPORT: We report the case of a 78-year-old non-smoker woman with stage IV EGFR L858R-positive lung adenocarcinoma presented with T790M mutation after five years of treatment with gefitinib. The patient was started on osimertinib, but after two and a half years of treatment experienced disease progression. The analyses of circulating tumor DNA using next-generation sequencing showed, together with the pre-existing T790M and exon 21 L858R, the presence of the EGFR C797G resistance mutation. CONCLUSION: Our case report revealed a rare EGFR-dependent acquired resistance mutation to osimertinib in circulating tumor DNA. Liquid biopsy appears to be a promising resource to understand the biology of osimertinib resistance by clonal evolution monitoring and the identification of novel resistance mechanisms. PMID:34410991 | DOI:10.21873/invivo.12586 View on the web Inoreader. Take back control of your news feed. Follow us on Twitter and Facebook.