CP-675,206 (tremelimumab) is a fully humanized monoclonal antibody that binds to activated T lymphocytes and by enhancing their activation may produce a stimulation of the immune response against tumoral or viral antigens. In this clinical trial, the ability of tremelimumab to produce tumor responses among hepatitis C virus-infected patients with hepatocellular carcinoma not amenable to other therapies will be explored. Besides, the effect on the replication of the virus will be analysed.

Inclusion Criteria:

• Unequivocal diagnosis of HCC
• unresectable disease not amenable to locoregional treatment.
• a 4-week washout period after sorafenib or any other systemic agent
• a 2-month washout period after internal or external radiation
• HCV chronic infection
• Child-Pugh stage A or B
• Measurable disease according to RECIST criteria
• ECOG < 2
• expected survival > 3 months
• Adequate liver, renal and blood functions
• ability to sign informed consent

Exclusion Criteria:

• previous treatment with an anti-CTL-4 agent
• serious infections or disease compromising general health status
• autoimmune disease that requires therapy
• treatment with immunosuppressors
• treatment with investigational agents
• other neoplasms except skin and bladder superficial tumors
• pregnancy or lactation
• SNC metastasis
• HIV infection
• relevant heart disease (NYHA class III or IV)