Triple-Dose Furmonertinib for Leptomeningeal Metastases in Advanced Epidermal Growth Factor Receptor (EGFR) L858R-Mutated Lung Adenocarcinoma: A Case Report.

Leptomeningeal metastases (LM) represent a severe and life-threatening manifestation of advanced non-small cell lung cancer (NSCLC). Despite advances in epidermal growth factor receptor (EGFR)-targeted therapies, central nervous system involvement continues to present major therapeutic challenges. We report a 73-year-old woman with EGFR L858R-mutated NSCLC who developed LM after multiple lines of therapy, including gefitinib, osimertinib, chemotherapy, anti-angiogenic therapy, and radiotherapy. Treatment with high-dose furmonertinib (240 mg daily) combined with bevacizumab resulted in symptom relief and additional survival. Remarkably, her overall survival exceeded six years from initial diagnosis. This case highlights the potential role of dose-escalated furmonertinib as salvage therapy in LM after osimertinib resistance and underscores the importance of sequential and multimodal management in advanced EGFR-mutant NSCLC.