This clinical trial is focused on studying the effects of a new treatment for biliary tract cancer, which includes types like intrahepatic or extrahepatic cholangiocarcinoma and muscle invasive gallbladder cancer. The treatment being tested is called rilvegostomig, also known by its code name AZD2936. It is a type of protein treatment given through an infusion, which means it is delivered directly into the bloodstream. The study will also involve the use of various chemotherapy drugs, including gemcitabine, capecitabine, cisplatin, and tegafur, which are commonly used to treat cancer. These drugs will be given either by infusion or orally, depending on the specific medication.

The purpose of this study is to determine if rilvegostomig, when combined with chemotherapy, is safe and effective in delaying the return of cancer after surgery. Participants in the study will be randomly assigned to receive either the new treatment combination or a placebo with chemotherapy. The study will be conducted in a double-blind manner, meaning neither the participants nor the researchers will know who is receiving the actual treatment or the placebo. This helps ensure the results are unbiased. The study will take place over several months, with regular check-ups and assessments to monitor the participants’ health and the progression of the disease.

Throughout the study, the main focus will be on measuring how long participants remain free from cancer recurrence, known as recurrence-free survival. Other important aspects being evaluated include overall survival, which is the length of time participants live after treatment, and how well participants tolerate the treatment. The study aims to provide valuable information on whether rilvegostomig can be a beneficial addition to the current treatment options for biliary tract cancer.