Real-world outcomes of pembrolizumab monotherapy in non-small cell lung cancer in Japan: A post-marketing surveillance.

This post-marketing surveillance (PMS) was initiated in Japan to identify factors affecting the safety and effectiveness of pembrolizumab monotherapy in patients with advanced non-small cell lung cancer (NSCLC) with programmed cell death ligand-1 (PD-L1) expression. This PMS was conducted from December 2016 to June 2019 at 717 centers across Japan. Patients with unresectable advanced/recurrent NSCLC who received pembrolizumab monotherapy as first-line (1L) treatment for PD-L1-expressing tumors (Tumor Proportion Score [TPS] ≥ 50%) or second-line or later (2L+) treatment for tumors with PD-L1 TPS ≥ 1% were enrolled and followed up for 1 year. Of 2805 registered patients, 2740 and 2400 comprised the safety and effectiveness analysis sets, respectively. The median age (range) was 69 (27-92) years; 55.7% and 29.2% of patients experienced treatment-related adverse events and adverse events of special interest (AEOSIs), respectively. More common AEOSIs included interstitial lung disease, endocrine disorders, liver dysfunction, colitis/severe diarrhea, infusion reactions, and severe skin disorders. The frequency of experiencing ≥2 AEOSIs was low (1L, 6.5%; 2L+, 2.8%). Most AEOSIs occurred within 150 days after initiation of pembrolizumab monotherapy. At 1-year follow-up, the objective response rate was 39.2% (1L, 51.5%; 2L+, 30.0%). In conclusion, the 1-year safety and effectiveness of pembrolizumab monotherapy in patients with unresectable advanced/recurrent NSCLC as 1L treatment for tumors with PD-L1 TPS ≥ 50% and 2L+ treatment for tumors with PD-L1 TPS ≥ 1% were similar to those reported in phase 2/3 trials.