Osimertinib 160 mg daily for advanced non-small cell lung cancer with leptomeningeal metastasis: A case report.

Advanced non-small cell lung cancer (NSCLC) with leptomeningeal metastases (LM) is associated with a dismal prognosis of typically 3-9 months. In preclinical and clinical studies, the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor osimertinib has demonstrated activity in the central nervous system (CNS), and studies are ongoing. We report here a case of osimertinib used at 160 mg once daily in a heavily pretreated patient with EGFR exon 20 T790M-negative advanced NSCLC with LM to achieve a partial response, including shrinkage of the LM, for up to 12 months until further progression. The case suggests the feasibility of using osimertinib at a twofold standard dose to treat CNS metastases, irrespective of the T790M mutation status.