A Phase 2b Study of Modified Vaccinia Virus to Treat Patients Advanced Liver Cancer Who Failed Sorafenib

KEY Inclusion Criteria: * Diagnosis of primary HCC by tissue biopsy (histological/cytological diagnosis), or clinical diagnosis * Previously treated with sorafenib for ≥ 14 days and has discontinued sorafenib treatment at least 14 days prior to randomization due to either intolerance or radiographic progression NOTE: Sorafenib is NOT required to be the most recent treatment received for HCC * ECOG performance status 0, 1 or 2 * Child-Pugh Class A; or Child-Pugh Class B7 without clinically significant ascites * Hematocrit ≥30% or Hemoglobin ≥10 g/dL * Tumor status: Measurable viable tumor in the liver and injectable under imaging-guidance; At least one tumor in the liver that has not received prior local-regional treatment OR that has exhibited \>25% growth in viable tumor size since prior local-regional treatment. KEY Exclusion Criteria: * Received sorafenib within 14 days prior to randomization * Received systemic anti-cancer therapy other than sorafenib within 28 days of randomization * Prior treatment with JX-594 * Platelet count \< 50,000 PLT/ mm3 * Total white blood cell count \< 2,000 cells/mm3 * Prior or planned organ transplant * Known significant immunodeficiency due to underlying illness (e.g. HIV/AIDS) and/or medication * Severe or unstable cardiac disease * Viable CNS malignancy associated with clinical symptoms * Pregnant or nursing an infant * History of inflammatory skin condition (e.g., eczema requiring previous treatment, atopic dermatitis)