Continued Cemiplimab Beyond Progression With Addition of Chemotherapy in Patients With Advanced NSCLC With PD-L1 Expression of 50% or Higher: 5-Year Follow-Up From EMPOWER-Lung 1.

Introduction: Treatment options are limited for patients with advanced NSCLC who progress on anti-programmed cell death-ligand 1 (anti-PD-L1) monotherapy. Second-line platinum-based chemotherapy provides a short progression-free survival (PFS) of approximately 3 to 4 months. The EMPOWER-Lung 1 study allowed continued cemiplimab with the addition of platinum-based chemotherapy after progression as a second-line treatment (cemiplimab beyond progression [CBP]). Here, we report long-term outcomes in this setting. Methods: Patients ( Results: In the CBP setting, the objective response rate was 27.4%, the median duration of response was 11.5 months (95% confidence interval: 6.0-19.3), and median PFS was 6.4 months (95% confidence interval: 6.1-9.1). Median overall survival from the time of randomization was 27.4 months (including 15.1 mo after the addition of chemotherapy). CBP treatment benefit was observed irrespective of histology, PD-L1 levels, or response to initial first-line cemiplimab monotherapy. Grade 3 or higher treatment-emergent adverse events occurred in 35.6% of patients, and immune-mediated adverse events occurred in 2.7% of patients. Conclusions: This exploratory analysis revealed the clinical benefit of continuing cemiplimab after progression with the addition of chemotherapy, without new safety signals.