M7824 Monotherapy in Locally Advanced or Metastatic Second Line (2L) Biliary Tract Cancer (Cholangiocarcinoma and Gallbladder Cancer)

Inclusion Criteria

• Are participants with histologically or cytologically confirmed locally advanced or metastatic BTC.
• Availability of tumor (primary or metastatic) archival material or fresh biopsies is mandatory
• Participants with BTC must have failed or be intolerant to 1L systemic platinum-based chemotherapy administered for locally advanced or metastatic disease. Only one prior treatment line is allowed
• Disease must be measurable with at least 1 unidimensionally measurable lesion by RECIST 1.1
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) of 0 to 1
• Life expectancy >= 12 weeks as judged by the Investigator
• Adequate hematological function defined by white blood cell (WBC) count >= 3 * 10^9/Litre with absolute neutrophil count (ANC) >= 1.5 * 109/Litre, lymphocyte count >= 0.5 * 10^9/Litre, platelet count >=75 * 10^9/Litre, and hemoglobin (Hgb) >= 9 grams/decilitre
• Adequate hepatic function defined by a total bilirubin level =< 1.5 * upper limit of normal (ULN), an aspartate aminotransferase (AST) level =< 2.5 * ULN, and an alanine aminotransferase (ALT) level =<2.5 * ULN. For participants with liver involvement in their tumor, AST =< 5.0 * ULN and ALT =< 5.0 * ULN is acceptable
• Adequate coagulation function defined as prothrombin time (PT) or international normalized ratio (INR) =< 1.5 * ULN unless the participant is receiving anticoagulant therapy
• Albumin >= 3.0 grams/decilitre
• Hepatitis B virus (HBV) deoxyribonucleic acid (DNA) positive participants must be treated and on a stable dose of antivirals
• Adequate renal function defined by either creatinine =< 1.5 * ULN or an estimated creatinine clearance (CCr) > 40 milliliter (mL) per minute (min) according to the Cockcroft-Gault formula or by measure of CCr from 24-hour urine collection
• Other protocol defined inclusion criteria could apply

Exclusion Criteria

• Ampullary cancer was excluded
• Significant acute or chronic infections
• Active autoimmune disease that might deteriorate when receiving an immunostimulatory agent
• Interstitial lung disease or its history
• Participants who were not eligible for or have not been treated with 1L systemic chemotherapy
• Anticancer treatment within 21 days before the start of study intervention
• Concurrent treatment with nonpermitted drugs
• Prior participation in a M7824 clinical trial
• Prior therapy with other immunotherapy or checkpoint inhibitors, such as anti-PD 1, anti PD L1, anti- cytotoxic T-cell lymphocyte-4 (CTLA-4) antibodies.
• Pregnancy or breast feeding
• Systemic anticancer treatment after failing 1L platinum-based chemotherapy
• Other protocol defined exclusion criteria could apply