Advanced non-small cell lung cancer patients with leptomeningeal metastases tend to have a worse prognosis. Currently, no standard therapeutic regimen for LM has been established because of its rarity and heterogeneity. Targeted therapy is the primary treatment of patients with EGFRm of NSCLC. The drug concentration in cerebrospinal fluid is the key factors affecting the curative effect of intracranial metastatic lesions. The widespread application of EGFR-TKIs in clinical practice has significantly prolonged the survival period of patients with EGFR mutations, but the standard dose of first- and second-generation EGFR-TKIs show poor control of intracranial metastasis.Furmonertinib is a third-generation EGFR-TKI targeting both sensitising EGFR and EGFR T790M mutations. Phase 2 clinical study of furmonertinib revealed that furmonertinib was clinically effective with acceptable toxicity in patients with EGFR T790M mutated advanced NSCLC, including in patients with CNS metastases. At present, some study has found that the dynamic changes of EGFR in plasma ctDNA can be used to evaluate the prognosis of NSCLC patients. Some study has also observed that the copy number variations in CSF ctDNA of NSCLC patients with LM are related to the curative effect. Therefore, CSF ctDNA may become a new biomarker to assess the therapeutic effect of LM. This is a single-center, open, single-arm, exploratory phase 2 trial evaluating the clinical efficacy and safety of Furmonertinib in EGFR mutated NSCLC patients with leptomeningeal metastasis and to explore the feasibility of CSF ctDNA detection for efficacy evaluation.
The goal of this clinical trial is to evaluate the clinical efficacy and safety of Furmonertinib in EGFR mutated NSCLC patients with leptomeningeal metastasis and to explore the feasibility of CSF ctDNA detection for efficacy evaluation. Participants will be treated with 160mg Furmonertinib daily and tumor evaluation will be performed every 6-8 weeks. The participants' blood and cerebrospinal fluid samples will be collected three times during the study for ctDNA detection.