Evaluating High-dose Furmonertinib with Bevacizumab and Pemetrexed for EGFRm NSCLC with Leptomeningeal Metastasis

The primary objective of this clinical study is to evaluate the efficacy of high-dose furmonertinib combined with bevacizumab and pemetrexed (triple therapy) in the treatment of non-small cell lung cancer (NSCLC) with leptomeningeal metastasis and epidermal growth factor receptor mutation (EGFRm) through overall survival (OS). The secondary objectives are to further assess the efficacy of the triple therapy in patients with EGFRm and leptomeningeal metastasis, including time to treatment failure (TTF), leptomeningeal objective response rate (ORR-LM), and clinical response rate.The study will also evaluate the impact of the triple therapy on quality of life using the EORTC QLQ-C30 scale and assess the safety of the therapy in EGFRm NSCLC patients with leptomeningeal metastasis, focusing primarily on adverse events and their severity (graded according to CTCAE v5.0), as well as their frequency.The exploratory objectives are to assess changes in intracranial pressure and the improvement rate of cerebrospinal fluid (CSF) before and after the triple therapy treatment. Additionally, the study will compare the genomic and epigenomic profile changes in circulating tumor DNA (ctDNA) from peripheral blood and cell-free DNA (cfDNA) from cerebrospinal fluid before and after treatment, and analyze their correlation with clinical outcomes, drug efficacy, and other clinical indicators. The primary endpoint of this study is overall survival (OS). The secondary endpoints include time to treatment failure (TTF), leptomeningeal objective response rate (ORR-LM), clinical response rate, and quality of life assessment (EORTC QLQ-C30).The safety endpoints are adverse events and their severity (graded according to CTCAE v5.0), as well as the frequency of occurrence. A total of 60 patients are planned to be enrolled, targeting eligible advanced NSCLC patients with EGFR mutations and leptomeningeal metastasis. The intervention consists of furmonertinib (240 mg/d, po) combined with bevacizumab (15 mg/kg, every 3 weeks, ivgtt) and pemetrexed (50 mg) intrathecal chemotherapy / pemetrexed (500 mg/m²) intravenous chemotherapy, administered every 3 weeks.