This clinical trial is focused on studying a type of cancer known as Biliary Tract Cancer (BTC), which affects the bile ducts, gallbladder, and other parts of the biliary system. The trial is specifically looking at cases where the cancer is advanced and has a characteristic called HER2-positive. This means that the cancer cells have more of a protein called HER2 on their surface, which can make the cancer grow more quickly. The study will test a new treatment combination that includes a drug called zanidatamab, which is being tested under the code name JZP598. This drug will be used alongside standard treatments, which include cisplatin and gemcitabine, and may also include drugs that target the immune system, such as durvalumab or pembrolizumab.

The purpose of the study is to compare the effectiveness of the new treatment combination with the standard treatment alone. Participants in the study will receive these medications through an intravenous infusion, which means the drugs are given directly into a vein. The study will follow participants over a period of time to see how well the cancer responds to the treatment and to monitor any side effects. The trial will also look at how long participants live without the cancer getting worse and their overall survival.

Participants will be randomly assigned to receive either the new treatment combination or the standard treatment. The study will involve regular visits to the clinic for treatment and monitoring. The trial aims to provide more information about the potential benefits and risks of adding zanidatamab to the current treatment options for advanced HER2-positive biliary tract cancer. This research could help improve future treatment strategies for this type of cancer.