Efficacy and Resistance Mechanisms of IP in NSCLC With Leptomeningeal Metastases

This is a prospective interventional clinical study aimed at investigating the efficacy and resistance mechanisms of intrathecal pemetrexed in advanced NSCLC patients with EGFR, ALK, and ROS1 mutations presenting leptomeningeal metastases. Approximately 30 advanced NSCLC patients with EGFR, ALK, and ROS1 mutations, who have developed leptomeningeal metastases following TKI resistance, will receive intrathecal pemetrexed. Cerebrospinal fluid samples will be collected before and after pemetrexed resistance to analyze molecular mechanisms and differences. Second-generation gene detection will be performed to identify potential resistance mechanisms to pemetrexed. The study is expected to commence recruitment in mainland China around April 2024, with an anticipated completion date in April 2025.