Inclusion Criteria:

        - Patients with locally advanced or metastatic biliary tract carcinoma including
        adenocarcinoma of the intra- and/or extra-hepatic bile ducts and gallbladder carcinoma.

        Patients with ampullary cancers are excluded.

          -  Patients must only have received and progressed on first-line gemcitabine and
             platinum-based chemotherapy in metastatic/advanced setting and should not have
             received prior anti-PD-(L)1 therapy. Patients with known fibroblast growth factor
             receptor 2 (FGFR2) fusion or rearrangement, or isocitrate dehydrogenase 1 (IDH1)
             mutation will be excluded.

          -  Patients with measurable disease according to RECIST v1.1

          -  Patients with an ECOG PS of 0 or 1, and anticipated life expectancy of ≥3 months

          -  Patients must have adequate organ function as indicated by laboratory values

          -  Adequate contraception required as appropriate

        Exclusion Criteria:

          -  Patients with central nervous system (CNS) malignancy, untreated or unstable
             metastases

          -  Patients with significant cardiovascular disease

          -  Patients with

               1. Active thrombosis, or a history of deep vein thrombosis or pulmonary embolism,
                  within 4 weeks prior to the first study drug dose

               2. Active uncontrolled bleeding or a known bleeding diathesis

          -  Patients with a significant pulmonary disease or condition

          -  Patients with a current or recent (within 6 months) significant gastrointestinal
             disease or condition

          -  Patients with Gilbert's syndrome or patients with UGT1A1*28 homozygosity (also known
             as UGT1A1 7/7 genotype)

          -  Patients with a significant ocular disease or condition

          -  Patients with an active, known or suspected autoimmune disease

          -  Patients with any other serious/active/uncontrolled infection

          -  Patients with a history of organ transplantation

          -  Patients with human immunodeficiency virus (HIV) (HIV 1/2 antibodies) or active
             infection with hepatitis B virus or hepatitis C virus

          -  Prior therapy with irinotecan or with anti-PD-(L)1, anti-LAG-3 or anti-TIM-3
             containing regimen, or combination with any other systemic or localized therapy or any
             other IO therapies.

          -  Patients must not be on warfarin, strong cytochrome P450 (CYP) 3A4 inducers, strong
             CYP3A4 inhibitors, or strong UGT1A1 inhibitors.

          -  Patients with a history of significant toxicities associated with previous
             administration of immune checkpoint inhibitors that necessitated permanent
             discontinuation of that therapy

          -  Patients with a known or suspected hypersensitivity to any of the excipients of
             formulated study drug

          -  Patients with unresolved >Grade 1 toxicity associated with any prior antineoplastic
             therapy