Study of Safety and Tolerability of PDR001 in Combination With Sorafenib and to Identify the Maximum Tolerated Dose and/or Phase 2 Dose for This Combination in Advanced Hepatocellular Patients

Inclusion Criteria: * Histologically or cytologically confirmed advanced (unresectable and/or metastatic) HCC * Patients with advanced HCC not amenable for surgical or loco-regional treatment * At least one measureable tumor lesion that that has not been previously locally * Patients with current cirrhotic status of Child-Pugh class A only (5-6 points with total bilirubin \< 2 mg/dL for dose-escalation) with no encephalopathy and no clinical ascites (ascites controlled by diuretics is also excluded in this study). * Patient has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Patient must meet required laboratory values at the screening * Normal electrocardiogram at screening Exclusion Criteria: * Known fibrolamellar HCC, sarcomatoid HCC, or mixed cholangiocarcinoma and HCC * Invasion of the main portal vein and/or tumor involvement in more than 50% of the liver (applicable only for the dose-escalation part) * Patients with Portal-caval shunts * Prior or concomitant systemic anti-cancer treatment for advanced disease * Systemic chronic steroid therapy (≥ 10mg/day prednisone or equivalent) or any immunosuppressive therapy 7 days prior to planned date for first dose of study treatment. Topical, inhaled, nasal and ophthalmic steroids are allowed. * Cardiac or cardiac repolarization abnormality * Patients with active Hepatitis B infection (HBsAg positive) that are not receiving antiviral treatment are excluded * Patients with positive test for hepatitis C ribonucleic acid (HCV RNA) * Loco-regional treatment within 4 weeks prior to initiation of study treatment.