LAUSR

Abstract Several selective mesenchymal–epithelial transition (MET) inhibitors have recently demonstrated favorable systemic efficacy in MET exon 14 skipping mutation-positive non-small cell lung cancer. However, there are limited data on their efficacy against central nervous system (CNS) metastasis, especially leptomeningeal seeding. Recently, we encountered a case of a 65-year-old woman who was diagnosed with metastatic lung adenocarcinoma. As routine molecular testing showed no genomic alterations, including epidermal growth factor receptor mutation and anaplastic lymphoma kinase translocation, the patient received a frontline platinum-doublet followed by paclitaxel. However, the tumor did not respond to these therapies, and her condition became deleterious owing to extensive brain and leptomeningeal metastases. Plasma genotyping revealed that the tumor harbored a MET exon 14 skipping mutation, and we started capmatinib, a selective MET inhibitor. The CNS lesions markedly decreased and the performance status of the patient dramatically improved. Our report highlights the significant CNS activity of capmatinib, even in cases of leptomeningeal metastasis. In addition, this report emphasizes the importance of the active utilization of molecular profiling to detect rare but druggable genetic alterations for the better management of patients with lung cancer.