Phase II study of IRInotecan treatment after COmbined chemo‐immunotherapy for extensive‐stage small cell lung cancer: Protocol of IRICO study

Abstract Introduction Combined treatment using anti‐programmed death‐ligand 1 antibody (anti‐PD‐L1) and platinum‐etoposide is the current standard first‐line treatment for patients with extensive‐stage (ES) small cell lung cancer (SCLC). However, the best treatment for relapsed ES‐SCLC after the first‐line treatment remains unclear. There are some approved chemotherapeutic agents that can be used against ES‐SCLC, and treatment with irinotecan is well established as both a monotherapy and a combined therapy, in combination with platinum. Therefore, we conduct a phase II study with irinotecan in the second‐ or later‐line setting for patients with ES‐SCLC who have been previously treated with combined treatment. Methods Our study will enroll total 30 patients who are diagnosed with ES‐SCLC and have experienced disease progression after the combined treatment. Patients will receive irinotecan on days 1, 8, and 15, which will be repeated every 4 weeks. Doses of irinotecan (100/80/60 mg/m2) will be determined according to the type of UGT1A1 gene polymorphism, and the treatment will be discontinued following disease progression, intolerance, withdrawal of patient consent, and based on the investigator's decision. The primary endpoint of the study is the response rate, and the secondary endpoints are overall survival, progression‐free survival, and safety. Discussion Since the present first‐line treatment has been changed to the combined treatment, the second‐ or later‐line treatment should be re‐evaluated for patients with relapsed SCLC. Irinotecan is a major chemotherapeutic agent used for SCLC. This study demonstrates and re‐evaluates the clinical benefits of irinotecan after combined treatment with anti‐PD‐L1 and platinum‐etoposide for patients with ES‐SCLC. Registration details This study was registered in the Japan Registry of Clinical Trials (no. jRCT s071210090) on November 4, 2021.