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.