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

This is a Phase 2, open-label, pilot safety study designed to evaluate the safety and tolerability of sequential therapy consisting of Pexa-Vec (JX-594) followed by standard sorafenib in patients with advanced, unresectable primary hepatocellular carcinoma (HCC).

Patients will receive an initial intravenous (IV) infusion of Pexa-Vec at a dose of 1 x 10\^9 plaque-forming units (pfu) on Day 1. This is followed by two intratumoral (IT) injections of Pexa-Vec on Day 8 and Day 22, each at a total dose of 1 x 10\^9 pfu divided among 1 to 5 hepatic tumors. Starting on Day 25 (approximately 3 days after the final regular dose of Pexa-Vec), patients will initiate standard oral sorafenib therapy twice daily. For patients with viable hepatic tumor tissue at Week 12, an optional additional IT dose of Pexa-Vec may be administered.

The primary objective of this study is to assess the safety and toxicity of this sequential regimen, determined by the incidence of treatment-related Grade 3 and Grade 4 adverse events (AEs) and treatment-related serious adverse events (SAEs). Secondary objectives include evaluating the disease control rate (DCR) at 12 weeks, overall survival (OS) time, and radiographic response rate based on modified RECIST (mRECIST 1.0) and/or Choi criteria.