Safety and efficacy of camrelizumab combined with radiotherapy as neoadjuvant therapy for locally advanced esophageal squamous cell carcinoma: a prospective single-arm phase II clinical trial protocol

Background Neoadjuvant chemoradiotherapy followed by esophagectomy is the standard of care for locally advanced esophageal squamous cell carcinoma (ESCC). However, approximately 30% of patients still develop distant metastases and have a high incidence of treatment-related adverse events. Immunotherapy, as a new modality for anti-cancer treatment, has shown promising clinical benefits for patients with ESCC. The synergistic effects of immunotherapy and radiotherapy make their combination promising as neoadjuvant treatment for locally advanced ESCC. Methods All participants who meet the inclusion criteria will be enrolled after signing the informed consent form. Patients with thoracic segment esophageal cancer with clinical stage T2-3 N0 M0 or T2-3 N + M0 will be included. A total of 25 patients are to be recruited for the study. Twelve patients will be recruited in phase I, with at least two achieving major pathological response (MPR) before entering phase II. They will be treated with radical surgery within 4-8 weeks after the completion of two cycles of neoadjuvant radiotherapy in combination with camrelizumab according to the study schedule. The primary endpoint is the major pathological remission rate of all per-protocol patients. The secondary endpoints are the R0 resection rate, pathological complete remission rate, and adverse events. The interim analysis will be conducted after 12 patients have been enrolled. The trials will be terminated when more than two treatment-related deaths occur or fewer than five patients have major pathological remission. Discussion We designed this prospective single-arm phase II clinical study to evaluate the combination of camrelizumab and standard radiotherapy as preoperative neoadjuvant therapy for patients with resectable ESCC as part of the quest for better treatment options for patients with locally advanced ESCC. Trial registration This trial protocol has been registered on the NIH Clinical Trials database (www.clinicaltrials.gov/, NCT05176002. Registered on 2022/01/04). The posted information will be updated as needed to reflect protocol amendments and study progress.