First-Line Pembrolizumab Monotherapy for Advanced NSCLC With Programmed Death-Ligand 1 Expression Greater Than or Equal to 50%: Real-World Study Including Older Patients in Japan

INTRODUCTION: Pembrolizumab became available in Japan in February 2017 for first-line monotherapy of unresectable advanced and metastatic NSCLC with programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) greater than or equal to 50%. This retrospective chart review study aimed to describe real-world clinical outcomes of first-line pembrolizumab monotherapy, including for patients 75 years or older, who are under-represented in clinical trials. METHODS: We identified patients (≥20 y old) at 23 sites initiating first-line pembrolizumab monotherapy from July 1, 2017, to December 20, 2018, for stages IIIB, IIIC, and IV NSCLC with PD-L1 TPS greater than or equal to 50% and Eastern Cooperative Oncology Group performance status of 0 to 2 or unknown. Patients with actionable genomic alterations (EGFR, ALK, ROS1, BRAF) and clinical trial participants were excluded. Time-to-event outcomes were estimated using Kaplan-Meier, with data cutoff on September 30, 2019. RESULTS: Of 441 eligible patients (78% men), 303 (69%) were younger than 75 years and 138 (31%) were 75 years or older; median age was 70 years. With median follow-up of 13.5 months, median overall survival (OS) was not reached (NR); 12- and 24-month OS rates were 72% and 58%, respectively. For ages younger than 75 and 75 years or older, median OS was NR and 23.5 months (95% confidence interval: 16.2–NR), respectively; 12-month OS rates were 74% and 67% and 24-month OS rates were 62% and 48%, respectively. Median real-world progression-free survival was similar in the two age groups (10.1 and 9.5 mo, respectively), as was median real-world time on treatment with pembrolizumab (5.7 and 5.6 mo). CONCLUSIONS: These findings complement clinical trial results, adding real-world evidence supporting benefits of first-line pembrolizumab monotherapy for advanced NSCLC with PD-L1 TPS greater than or equal to 50%, including for patients 75 years or older.