A Study of Atezolizumab With or Without Bevacizumab in Combination With Cisplatin Plus Gemcitabine in Patients With Untreated, Advanced Biliary Tract Cancer

Inclusion Criteria:

• Considered to be eligible to receive platinum-based chemotherapy, in theinvestigator's judgment

• Documentation of recurrent/metastatic or locally advanced unresectable disease basedon computed tomography (CT) or magnetic resonance imaging (MRI) scans

• Histologically or cytologically confirmed diagnosis of iCCA, eCCA, or GBC

• No prior systemic therapy for advanced BTC

• At least one measurable untreated lesion (per RECIST v1.1)

• Adequate biliary drainage with no evidence of ongoing infection

• Eastern Cooperative Oncology Group Performance Status of 0 or 1

• Life expectancy of > 3 months

• Adequate hematologic and end-organ function

• For women of childbearing potential: agreement to remain abstinent (refrain fromheterosexual intercourse) or use contraceptive methods, and agreement to refrainfrom donating eggs

• For men: agreement to remain abstinent (refrain from heterosexual intercourse) oruse a condom, and agreement to refrain from donating sperm

Exclusion Criteria:

• Recurrent disease <=6 months after curative surgery or <= 6 months after thecompletion of adjuvant therapy

• Prior local regional therapy such as radioembolization

• Combined or mixed hepatocellular/cholangiocarcinoma

• Clinically significant hepatic encephalopathy within the 12 months prior to Day 1 ofCycle 1

• National Cancer Institute Common Terminoogy Criteria for Adverse Events Grade >= 2peripheral neuropathy

• Prior bleeding event due to untreated or incompletely treated esophageal and/orgastric varices within 6 months prior to Day 1 of Cycle 1

• Pregnant or breastfeeding, or intending to become pregnant during the study orwithin 5 months after the final dose of atezolizumab or within 6 months after thefinal dose of bevacizumab, cisplatin or gemcitabine

• Active or history of autoimmune disease or immune deficiency

• History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-inducedpneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis onscreening chest computed tomography scan

• History of malignancy other than BTC within 5 years prior to screening, with theexception of malignancies with a negligible risk of metastasis or death

• Symptomatic, untreated, or actively progressing CNS metastases

• For patients with lung metastases, if one of the following criteria applies: Large,centrally located pulmonary metastases; Clear tumor infiltration into the thoracicgreat vessels seen on imaging; Clear cavitation of pulmonary lesions seen on imaging

• Active tuberculosis

• Co-infection with HBV and HCV

• Treatment with systemic immunostimulatory agents or immunosuppressive medication

• Inadequately controlled arterial hypertension

• History of hypertensive crisis or hypertensive encephalopathy

• Significant vascular disease

• Evidence of bleeding diathesis or significant coagulopathy

• Serious, non-healing or dehiscing wound, active ulcer, or untreated bone fracture

• Chronic daily treatment with a non-steroidal anti-inflammatory drug (NSAID)

• Preexisting renal impairment, myelosuppression, or hearing impairment