Osimertinib Improves overall survival of EGFR-mutant NSCLC patients with leptomeningeal metastases

OBJECTIVE: Osimertinib is a third-generation, irreversible, small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that can effectively penetrate the blood brain-barrier (BBB). This study mainly explored the factors affecting the prognosis of EGFR-mutant advanced non-small cell lung cancer (NSCLC) patients with leptomeningeal metastases (LM), and whether osimertinib could improve the survival benefit in these patients compared with those not treated with osimertinib. METHODS: We retrospectively analyzed patients who had been admitted with EGFR-mutant NSCLC and cytologically confirmed LM to the Peking Union Medical College Hospital between January 2013 and December 2019. Overall survival (OS) was defined as the primary outcome of interest. RESULTS: A total of 71 patients with LM were included in this analysis, with a median OS (mOS) of 10.7 months (95% CI [7.6, 13.8]). Among them, 39 patients were treated with osimertinib after LM while 32 patients were untreated. Patients treated with osimertinib had a mOS of 11.3 months (95%CI [0, 23.9]) compared with the untreated patients who had a mOS of 8.1 months (95%CI [2.9, 13.3]), with a significant difference between the groups (hazard ratio [HR]): 0.43, 95%CI:0.22–0.66, p = 0.0009). Multivariate analysis revealed the use of osimertinib were correlated with superior OS with a HR of 0.43 (95%CI [0.25, 0.75]), with a statistically significant difference (p = 0.003). CONCLUSIONS: Osimertinib can prolong the overall survival of EGFR-mutant NSCLC patients with LM and improve patient outcomes.