A Phase 1B, Multi-center, Open Label, Dose Escalation Study of Mapatumumab ([HGS1012], a Fully-human Monoclonal Antibody to TRAIL-R1) in Combination With Sorafenib as a First Line Therapy in Subjects With Advanced Hepatocellular Carcinoma

Inclusion Criteria:

- Moderate liver disease

- Test positive for hepatitis B surface antigen or hepatitis C antibody

- Locally advanced unresectable/untransplantable or metastatic hepatocellular carcinoma

- Age 18 years or older

Exclusion Criteria:

- Received investigational (not yet approved by a regulatory authority) or
non-investigational agent to treat hepatocellular carcinoma.

- Received radiation therapy within 4 weeks before randomization

- Major surgery within 4 weeks before randomization

- Minor surgery within 2 weeks before randomization

- Systemic steroids within 1 week before randomization

- Hepatic encephalopathy, per the investigator's evaluation

- History of clinically significant gastrointestinal bleeding requiring procedural
intervention within 4 weeks before enrollment

- History of any infection requiring hospitalization or antibiotics within 2 weeks
before randomization

- Known brain or spinal cord metastases

- History of other cancers within 5 years before enrollment

- Pregnant or breast-feeding women

- Known HIV infection