Durvalumab With Chemotherapy as First Line Treatment in Patients With Advanced Biliary Tract Cancers (aBTCs) (TOURMALINE)

Inclusion Criteria: Histologically confirmed, unresectable advanced or metastatic biliary tract carcinoma (BTC) including cholangiocarcinoma (intrahepatic or extrahepatic), gallbladder carcinoma, and ampulla of Vater (AoV) carcinoma Participants with unresectable or metastatic BTC A World Health Organisation Eastern Cooperative Oncology Group Performance Status (WHO/ECOG PS) of 0 to 2 At least one lesion that qualifies as a Response Evaluation Criteria in Solid Tumours version 1.1 (RECIST 1.1) target lesion at baseline Adequate organ and bone marrow function Body weight of > 30 kg Negative pregnancy test (serum) for women of childbearing potential Female participants must be one year post-menopausal (amenorrhoeic for 12 months without an alternative medical cause) Male and female participants and their partners must use an acceptable method of contraception as per the protocol. Exclusion Criteria: Any evidence of diseases such as severe or uncontrolled systemic diseases, including uncontrolled hypertension, active bleeding diseases, active infection, active interstitial lung disease/pneumonitis, serious chronic gastrointestinal conditions associated with diarrhoea, psychiatric illness/social situations, history of allogenic organ transplant Active or prior documented autoimmune or inflammatory disorders History of another primary malignancy, except for malignancy treated with curative intent and with no known active disease ≥ 5 years before the first dose of study intervention History of leptomeningeal carcinomatosis History of active primary immunodeficiency Known to have tested positive for human immunodeficiency virus [HIV] (positive HIV 1/2 antibodies) or active tuberculosis infection Participants co-infected with Hepatitis B virus (HBV) and Hepatitis C virus (HCV) or co-infected with HBV and Hepatitis D virus (HDV) Persistent toxicities (Common Terminology Criteria for Adverse Events [CTCAE] Grade > 2) caused by previous anticancer therapy History of, or current, brain metastases or spinal cord compression Known allergy or hypersensitivity to any of the study intervention or any of the study intervention excipients. Any concurrent chemotherapy, other than the one allowed in the study, investigational medicinal product (IMP), biologic, or hormonal therapy for cancer treatment Palliative radiotherapy with a limited field of radiation within 2 weeks of the first dose of study intervention, or radiotherapy with a wide field of radiation or radiotherapy affecting more than 30% of the bone marrow within 4 weeks before the first dose of study intervention Receipt of live attenuated vaccine within 30 days prior to the first dose of study intervention Major surgical procedure within 28 days prior to the first dose of IMP Prior exposure to immune-mediated therapy excluding therapeutic anticancer vaccines Receipt of the last dose of anticancer therapy within 28 days prior to the first dose of IMP