RecruitingPhase 2Drug trialFurmonertinib Combined With Intrathecal Chemotherapy and Stereotactic Radiotherapy (SRT) for EGFR-Mutated NSCLC Patients With Brain Parenchymal and Leptomeningeal MetastasesA Single-Arm Clinical Study of Furmonertinib (160mg) Combined with Intrathecal Chemotherapy (ITC) and Stereotactic Radiotherapy (SRT) as First-Line Treatment in EGFR Classic Mutation-Positive NSCLC Patients with Brain Parenchymal and Leptomeningeal Metastases