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 cytolog-ically 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 osi-mertinib 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.