Motoko Tachihara,1 Kayoko Tsujino,2 Takeaki Ishihara,3 Hidetoshi Hayashi,4 Yuki Sato,5 Takayasu Kurata,6 Shunichi Sugawara,7 Isamu Okamoto,8 Shunsuke Teraoka,9 Koichi Azuma,10 Haruko Daga,11 Masafumi Yamaguchi,12 Takeshi Kodaira,13 Miyako Satouchi,14 Mototsugu Shimokawa,15 Nobuyuki Yamamoto,9 Kazuhiko Nakagawa4 On behalf of members of the West Japan Oncology Group (WJOG)1Division of Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe City, Japan; 2Department of Radiation Oncology, Hyogo Cancer Center, Akashi City, Japan; 3Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe City, Japan; 4Department of Medical Oncology, Kindai University, Osakasayama City, Japan; 5Department of Respiratory Medicine, Kobe City Medical Center General Hospital, Kobe City, Japan; 6Department of Thoracic Oncology, Kansai Medical University Hospital, Hirakata City, Japan; 7Department of Pulmonary Medicine, Sendai Kousei Hospital, Sendai City, Japan; 8Research Institute for Diseases of the Chest, Graduate School of Medical Sciences, Kyushu University, Fukuoka City, Japan; 9Internal Medicine III, Wakayama Medical University, Wakayama, Japan; 10Division of Respirology, Neurology, and Rheumatology, Department of Internal Medicine, Kurume University School of Medicine, Fukuoka City, Japan; 11Department of Medical Oncology, Osaka City General Hospital, Osaka, Japan; 12Department of Thoracic Oncology, National Hospital Organization Kyushu Cancer Center, Fukuoka City, Japan; 13Departments of Radiation Oncology, Aichi Cancer Center Hospital, Nagoya City, Aichi, Japan; 14Department of Thoracic Oncology, Hyogo Cancer Center, Akashi City, Japan; 15Department of Biostatistics, Yamaguchi University Graduate School of Medicine Yamaguchi, Ube City, JapanCorrespondence: Motoko TachiharaDivision of Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe City, 650-0017, JapanTel +81-78-382-5660Fax +81-78-382-5661Email mt0318@med.kobe-u.ac.jpAbstract: Durvalumab (anti-programmed cell death ligand-1) administration after concurrent chemoradiotherapy (cCRT) has improved the survival of patients with unresectable, locally advanced (LA) stage III non-small cell lung cancer (NSCLC). Some patients are unable to complete cCRT and cannot receive immunotherapy due to poor performance status based on adverse events after cCRT. Immunotherapy plays an important role in anti-programmed cell death ligand-1 (PD-L1)-positive advanced NSCLC and is replacing chemotherapy. In addition, radiotherapy and immunotherapy have been reported to have a synergistic effect. This Phase II, multicenter study (DOLPHIN, WJOG11619L, JapicCTI-194840) is designed to assess the efficacy and safety of durvalumab plus concurrent curative radiation therapy for PD-L1-positive unresectable LA-NSCLC without chemotherapy. Unresectable LA stage III NSCLC patients aged 20 years or older with a World Health Organization/Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1 and PD-L1 positivity are enrolled. The patients will receive curative radiation therapy (60 Gy) plus durvalumab 10 mg/kg every 2 weeks (q2w) for up to 12 months until there is evidence of disease progression (PD) or unacceptable toxicity. The primary endpoint is the 12-month progression-free survival rate as assessed by an independent central review. The secondary endpoints are progression-free survival, overall survival, objective response rate, treatment completion rate, and safety. Recruitment began in September 2019.Keywords: clinical study, locally advanced non-small cell lung cancer, immunotherapy, programmed cell death ligand-1, durvalumab, radiation