The efficacy and safety of furmonertinib in patients with advanced EGFR-mutated NSCLC and leptomeningeal metastases.

e20525 Background: Leptomeningeal metastasis (LM) is a common and fatal complication in patients with advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor ( EGFR) mutation. This retrospective study aimed to evaluate the efficacy and safety of furmonertinib in patients with advanced EGFR-mutated ( EGFRm) NSCLC and LM. Methods: Eligible patients with confirmed advanced EGFRm NSCLC and LM were treated with furmonertinib. The primary endpoints were LM response rate and progression-free survival (PFS). Secondary endpoints were overall survival (OS) and adverse events (AEs). Results: This retrospective study analyzed the efficacy and safety of 31 EGFRm advanced NSCLC patients with LM at two hospitals between February 2020 to March 2023. The median age was 56 years (rang: 31-75), 22 (71.0%) were females. 19 (61.3%) patients had ECOG PS≥2 and all 31 patients (100%) had adenocarcinoma histology. For the treatment of LM, 19 (61.3%) patients received furmonertinib as first-line treatment, 8 (25.8%) patients as second-line treatment. 16 (51.6%) patients were treated with 240 mg of furmonertinib and 12 (38.7%) patients with 160 mg of furmonertinib. The median follow-up duration was 16.80 months (95% CI 12.71-20.89 months). LM objective response rate (ORR) was 75.0% and LM disease control rate (DCR) was 95.0% according to RANO-LM radiologic criteria. Overall ORR was 22.6% and DCR was 96.8%. Median LM duration of response (DoR) was 12.00 months (95% CI 7.40-16.60 months) and median overall DoR was 7.20 months (95% CI 3.60-10.80 months). 23 (74.2%) of the 31 patients had progressed or died by data cutoff. The median PFS was 11.70 months (95% CI 9.48-13.92 months) and the median OS was 18.40 months (95% CI 12.49-24.21 months). There was no significant difference in survival (median PFS: 11.70 months vs 10.90 months, p = 0.335; median OS: 18.40 months vs 13.50 months, p = 0.196) between the 19 patients who treated with furmonertinib as first-line therapy and those who treated with furmonertinib as second-line therapy. Although data on cerebrospinal fluid (CSF) clearance were not available, we observed improved neurologic function in 18 (75%) of 24 patients with baseline neurologic abnormalities. Logistic regression analysis showed that the therapeutic dose of furmonertinib was a positive predictor of OS in NSCLC patients harboring EGFR mutation with LM HR: 2.679 (1.004-7.147), P = 0.049. The most common AEs were rash, diarrhea and decreased appetite. However, most AEs were grade 1-2. Conclusions: Our study provides real-world clinical evidence that furmonertinib shows an encouraging efficacy and a manageable safety profile in patients with EGFRm NSCLC and LM.