Successful treatment of an osimertinib-resistant lung adenocarcinoma with an exon 18 EGFR mutation (G719S) with afatinib plus bevacizumab.

Exon 18 mutations account for only 3.6% of EGFR mutations, and tumors with exon 18 mutations are often unresponsive to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). We present a novel case of a lung adenocarcinoma with an exon 18 mutation resulting in a glycine to serine substitution at position 719 of the EGFR protein. The patient received osimertinib, a third generation EGFR-TKI, as the first-line treatment, but the disease progressed during treatment. Analysis of circulating free DNAs via next generation sequencing revealed TP53 mutations and EGFR and MET amplifications, as well as the exon 18 mutation. On the basis of these results, we administered afatinib, a second-generation TKI, and bevacizumab, a vascular endothelial growth factor inhibitor, as the second-line treatment. The patient's symptoms improved, and this treatment was continued for 12 months. This report suggests that afatinib plus bevacizumab can effectively treat osimertinib-refractory lung tumors with an exon 18 mutation.

Improvement strategies for successful next-generation sequencing analysis of lung cancer.

Aim: We aimed to improve the success rate of NGS (next-generation sequencing) analysis through improved strategies of lung cancer sampling. Materials & methods: The improvement strategies are as follows. Surgically resected specimens were preferentially submitted in cooperation with pathologists and surgeons. In bronchoscopic samples, the size of the sample collection device and the number of samples collected was increased. Results: The strategies increased the success rate of NGS analysis of DNA from 69.3 to 91.1%, and that of RNA from 64.6 to 90.0%. Discussion: The introduction of strategies aimed at improving the success of NGS analysis resulted in an improvement in the success rate and brought us closer to the delivery of effective precision medicine in cancer therapy.

Switching from first or second generation EGFR-TKI to osimertinib in EGFR mutation-positive NSCLC.

AIM: We evaluated the efficacy of a novel switch protocol for EGFR-TKIs for EGFR mutation-positive NSCLC. MATERIALS & METHODS: Clinical records were collected from the patients who had received one of two sequential combination strategies of EGFR-TKIs: Salvage use of osimertinib for T790M-mediated acquired resistance to an prior EGFR-TKI or switch use of osimertinib where an EGFR-TKI was switched to osimertinib before disease progression. RESULTS: Progression-free survival of osimertinib and time from the start of treatment until progression to osimertinib was comparable between the salvage use and switch use of osimertinib. CONCLUSION: Switch use of osimertinib seemed to produce improved efficacy for patients with activating EGFR mutations, because of the lack of patient selection via T790M.