Investigating Precision Medicine in the Adjuvant Setting in Biliary Tract Cancer

The objective of SAFIR-IMPACT BTC is to see whether, combining or replacing the standard adjuvant chemotherapy with a targeted therapy matched to the person's cancer, is better than the standard treatment alone in delaying or preventing the return of the cancer. Three different targeted therapies will be evaluated, each of which recognises a different type of abnormality in cancer cells: * Ivosidenib - a drug which acts on a specific abnormality in a protein called IDH1. * Futibatinib - a drug which acts on abnormalities in a protein called FGFR2 * Zanidatamab - a drug which acts on cancers that produce more than the usual quantity of a protein called HER2. The trial is composed of two phases: (i) An initial screening phase to identify a suitable patient population, during which a sample of the patient's tumour will be tested to see if it has one of the target abnormalities being studied (ii) a randomised comparative phase (for selected patients only) which consists of comparing two treatment options: some patients will receive the targeted therapy specific to the abnormality identified in their tumour, while others will receive the standard treatment. Patients will be assigned to one treatment or the other by a random draw: they will have a 2 in 3 chance of receiving the targeted therapy. Randomised participants will: * Take their assigned treatment for 6 months * Visit the clinic once every 3 weeks for checkups and tests * Keep a diary of their symptoms and the treatment they take at home Follow-up information will be collected for all participants until the end of the trial.