Study of Atezolizumab and Bevacizumab With Y-90 TARE in Patients With Unresectable Hepatocellular Carcinoma (HCC)

Subjects will be randomized to Y-90 TARE alone (Arm A) or Y-90 TARE followed by the combination of atezolizumab and bevacizumab (Arm B). The first 10 subjects randomized to Arm B (Y-90 TARE + bevacizumab + atezolizumab) will be assessed for safety after two cycles. If there are no Grade ≥ 3 unexpected toxicities; possibly, probably or definitely related to TARE in combination with bevacizumab and atezolizumab the combination will be deemed safe and accrual will resume. Subjects randomized to receive bevacizumab and atezolizumab (Arm B) will start the combination of bevacizumab and atezolizumab 4 weeks (± 1 week) after TARE treatment. Full recovery from the procedure is required prior to systemic treatment: * AST and ALT ≤ 5 x upper limit of normal (ULN) and total bilirubin ≤ 3 mg/dL * Manifestations of post-embolization syndrome (e.g., fever, nausea, vomiting, and abdominal pain) have resolved to National Cancer Institute Common Terminology Criteria for Adverse Events, Version 5.0 Grade 1 * No significant medical events (e.g., gastrointestinal \[GI\] bleeding, cardiac events, hepatorenal syndrome) during or after the TARE procedure. Arm B subjects will continue the study drugs for a total of 24 months from the TARE treatment, until intolerable toxicity or disease progression occur.