Preliminary Application of Toripalimab in Combination With GEMOX Regimen as a First-Line Treatment Option for Advanced Biliary Tract Tumors

AIMS/BACKGROUND: Advanced biliary tract cancer (BTC) is an aggressive malignancy, and often presents with poor prognostic outcomes despite standard chemotherapy. This study aimed to evaluate the preliminary efficacy and safety of toripalimab in combination with gemcitabine + oxaliplatin (GEMOX) as a first-line treatment option for advanced BTC. METHODS: This prospective, single-arm, single-center study enrolled 35 patients with advanced BTC. The patients received toripalimab in combination with GEMOX as first-line treatment at Zhejiang Cancer Hospital, China, between February 2021 and April 2023. Each patient received 1 to 11 treatment cycles, and the objective response rate (ORR) was evaluated before and after chemotherapy using the Response Evaluation Criteria for Solid Tumors (RECIST) version 1.1. Progression-free survival (PFS) and overall survival (OS) were assessed using the Kaplan-Meier method. Furthermore, adverse events and their severity were recorded to evaluate the safety profile of the treatment. RESULTS: A study cohort of 35 patients was enrolled (median age, 57 years), including 15 men and 20 women. Of them, 18 had intrahepatic cholangiocarcinoma, 14 had gallbladder cancer, and 3 had hilar cholangiocarcinoma. Metastatic lesions were most commonly observed in the lymph nodes, liver, and pelvis. The ORR was 20% (95% confidence interval [CI] 8.4%-36.9%), including 2 for complete response (CR) and 5 for partial response (PR). The median PFS and OS were found to be 8.5 and 16.5 months, respectively. All patients experienced adverse events, with 11 (31.42%) of the patients having grade 3 or higher adverse events. The most commonly observed adverse events included increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST), leukopenia, neutropenia, and thrombocytopenia. CONCLUSION: Toripalimab combined with GEMOX showed preliminary antitumor activity and an acceptable safety profile in patients with advanced BTC, warranting further validation in larger cohorts. CLINICAL TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR2600117154).