Wiley Acta Medica Okayama 1347-9032 111 12 2020 First-line pembrolizumab vs chemotherapy in metastatic non-small-cell lung cancer: KEYNOTE-024 Japan subset 4480 4489 EN Miyako Satouchi Department of Thoracic Oncology, Hyogo Cancer Center Kaname Nosaki Department of Thoracic Oncology, National Hospital Organization Kyushu Cancer Center Toshiaki Takahashi Division of Thoracic Oncology, Shizuoka Cancer Center Kazuhiko Nakagawa Department of Medical Oncology, Kindai University Faculty of Medicine Keisuke Aoe Department of Medical Oncology, National Hospital Organization Yamaguchi Ube Medical Center Takayasu Kurata Department of Thoracic Oncology, Kansai Medical University Akimasa Sekine Department of Respiratory Medicine, Kanagawa Cardiovascular and Respiratory Center Atsushi Horiike Department of Thoracic Medical Oncology, The Cancer Institute Hospital of the Japanese Foundation for Cancer Research Tatsuro Fukuhara Department of Respiratory Medicine, Miyagi Cancer Center Shunichi Sugawara Department of Pulmonary Medicine, Sendai Kousei Hospital Shigeki Umemura Department of Thoracic Oncology, National Cancer Center Hospital East Hideo Saka Department of Respiratory Medicine and Medical Oncology, National Hospital Organization Nagoya Medical Center Isamu Okamoto Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University Nobuyuki Yamamoto Internal Medicine III, Wakayama Medical University Hiroshi Sakai Department of Thoracic Oncology, Saitama Cancer Center Kazuma Kishi Department of Respiratory Medicine, Respiratory Center, Totanomon Hospital Nobuyuki Katakami Division of Integrated Oncology, Institute of Biomedical Research and Innovation Hospital Hidehito Horinouchi Department of Thoracic Oncology, National Cancer Center Hospital Toyoaki Hida Department of Thoracic Oncology, Aichi Cancer Center Hiroaki Okamoto Department of Respiratory Medicine and Medical Oncology, Yokohama Municipal Citizen’s Hospital Shinji Atagi Department of Thoracic Oncology, National Hospital Organization Kinki-Chuo Chest Medical Center Tatsuo Ohira Department of Surgery, Tokyo Medical University Shi Rong Han MSD, K.K. Kazuo Noguchi MSD, K.K. Victoria Ebiana Merck & Co., Inc. Katsuyuki Hotta Center for Innovative Clinical Medicine, Okayama University Hospital This prespecified subanalysis of the global, randomized controlled phase III KEYNOTE‐024 study of pembrolizumab vs chemotherapy in previously untreated metastatic non‐small‐cell lung cancer without EGFR/ALK alterations and a programmed death ligand 1 (PD‐L1) tumor proportion score of 50% or higher evaluated clinical outcomes among patients enrolled in Japan. Treatment consisted of pembrolizumab 200 mg every 3 weeks (35 cycles) or platinum‐based chemotherapy (four to six cycles). The primary end‐point was progression‐free survival; secondary end‐points included overall survival and safety. Of 305 patients randomized in KEYNOTE‐024 overall, 40 patients were enrolled in Japan (all received treatment: pembrolizumab, n = 21; chemotherapy, n = 19). Median progression‐free survival was 41.4 (95% confidence interval [CI], 4.2‐42.5) months with pembrolizumab and 4.1 (95% CI, 2.8‐8.3) months with chemotherapy (hazard ratio [HR], 0.27 [95% CI, 0.11‐0.65]; one‐sided, nominal P = .001). Median overall survival was not reached (NR) (95% CI, 22.9‒NR) and 21.5 (95% CI, 5.2‐35.0) months, respectively (HR, 0.39 [95% CI, 0.17‐0.91]; one‐sided, nominal P = .012). Treatment‐related adverse events occurred in 21/21 (100%) pembrolizumab‐treated and 18/19 (95%) chemotherapy‐treated patients; eight patients (38%) and nine patients (47%), respectively, had grade 3‐5 events. Immune‐mediated adverse events and infusion reactions occurred in 11 pembrolizumab‐treated patients (52%) and four chemotherapy‐treated patients (21%), respectively; four patients (19%) and one patient (5%), respectively, had grade 3‐5 events. Consistent with results from KEYNOTE‐024 overall, first‐line pembrolizumab improved progression‐free survival and overall survival vs chemotherapy with manageable safety among Japanese patients with metastatic non‐small‐cell lung cancer without EGFR/ALK alterations and a PD‐L1 tumor proportion score of 50% or higher. The trial is registered with Clinicaltrials.gov: NCT02142738. No potential conflict of interest relevant to this article was reported.