A Study of Pexa-Vec (JX-594) Prior to Sorafenib to Treat Unresectable Primary Hepatocellular Carcinoma

Inclusion Criteria:

* Histological confirmation or clinical/laboratory diagnosis of primary hepatocellular carcinoma (HCC)
* Cancer is not surgically resectable for cure
* Child Pugh A or B
* Performance Score: KPS score of ≥ 70
* Platelet count ≥ 50,000 plts/mm3
* Total bilirubin ≤ 2.5 x ULN
* AST, ALT \< 5.0 x ULN
* Acceptable coagulation status: INR ≤ 1.5 x ULN
* Acceptable kidney function: Serum creatinine \< 2.0 mg/dL
* Sorafenib naive or refractory to sorafenib therapy Tumor Status: At least one intrahepatic tumor, and at least ≥50% of the total intrahepatic viable tumor mass, measurable by CT and injectable under imaging-guidance (note: injected and/or viable tumors must be previously untreated or ≥20% increase in size since preceding local-regional treatment).

Exclusion Criteria:

* Known contraindications to sorafenib
* Pregnant or nursing an infant
* Significant immunodeficiency due to underlying illness (e.g. hematological malignancies, congenital immunodeficiencies and/or HIV infection/AIDS) and/or medication (e.g. high-dose systemic corticosteroids)
* History of exfoliative skin condition (e.g. severe eczema, ectopic dermatitis, or similar skin disorder) that at some stage has required systemic therapy
* Clinically significant and/or rapidly accumulating ascites, peri-cardial and/or pleural effusions
* Severe or unstable cardiac disease
* Current, known CNS malignancy
* Use of anti-platelet or anti-coagulation medication
* Use of the following anti-viral agents: ribavirin, adefovir, cidofovir (within 7 days prior to the first treatment), and PEG-IFN (within 14 days prior to the first treatment).
* Patients with household contacts who meet any of these criteria unless alternate living arrangements can be made during the patient's active dosing period and for 7 days following the last dose of study medication:
* Pregnant or nursing an infant
* Children \< 12 months old
* History of exfoliative skin condition that at some stage has required systemic therapy
* Significant immunodeficiency due to underlying illness (e.g. HIV/AIDS) and/or medication