Combination of Aumolertinib, Dabrafenib, and Trametinib for a Patient with Advanced Lung Adenocarcinoma with an Osimertinib-Induced BRAF V600E Mutation: A Case Report

Osimertinib has become the standard of care in the first-line treatment of advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations. Although previous studies reported that the BRAF V600E mutation is a unique resistance mechanism to osimertinib, the treatment of lung adenocarcinoma patients harboring both EGFR and acquired BRAF-V600E comutations remains unclear. Here, we report a case of a 36-year-old woman diagnosed with stage IV lung adenocarcinoma harboring the EGFR L858R mutation. She received osimertinib for 24 months and experienced progressive disease. Rebiopsy pathology revealed that the lung lesion was still adenocarcinoma, and NGS revealed gains of BRAF V600E and TP53 mutations in addition to the EGFR L858R mutation. This patient subsequently received aumolertinib in combination with dabrafenib and trametinib and achieved a complete response for 8 months. In conclusion, acquired BRAF-V600E mutations may contribute to osimertinib resistance. Aumolertinib plus BRAF inhibitors improves outcomes in patients with EGFR-L858R and acquired BRAF-V600E comutant lung adenocarcinoma in whom osimertinib treatment has failed.