Introduction: With the inspiring results of the PACIFIC trial in non-small-cell lung cancer (NSCLC), and the CAPIAN and IMpower133 trials in extensive-stage small-cell lung cancer (SCLC), immunotherapy has increasingly gained attention. Serplulimab, a PD-1 inhibitor, showed great antitumour activity in the ASTRUM-005 trial and has been recommended as first-line therapy in extensive-stage SCLC. Whether serplulimab following hypofractionation radiotherapy and chemotherapy could bring better outcomes in limited-stage SCLC remains to be answered.
Methods and analysis: We designed a prospective multicentre single-arm phase II clinical trial to evaluate both the efficacy and safety of chemoradiotherapy and consolidation by serplulimab in limited-stage SCLC. Eligible patients will receive standard chemotherapy for four cycles and concurrent thoracic radiotherapy with a total dose of 45 Gy in 3 weeks and a 3 Gy dose per fraction. Prophylactic cranial irradiation is recommended for responding patients. Serplulimab will be delivered afterwards every 3 weeks for up to 1 year. Based on sample size estimation, 55 patients will be enrolled in total.
Ethics and dissemination: Ethics approval was obtained from the Independent Ethics Committee of National Cancer Centre/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (22/236-3438).
Trial registration number: NCT05443646.
Keywords: Immunology; RADIOTHERAPY; Respiratory tract tumours.
© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.