US-based biotherapeutics firm SillaJen has started a Phase III study of its lead product candidate, Pexa-Vec (formerly JX-594), in patients with advanced liver cancer, also called hepatocellular carcinoma (HCC).

The Phase III trial (PHOCUS trial) is designed to evaluate the use of Pexa-Vec in treating HCC patients who have failed locoregional therapies, and are eligible for treatment with sorafenib (Nexavar), the only approved drug for advanced HCC.

A total of 600 patients who have not received prior systemic treatment for their cancer will be enrolled in this trial and they will be randomised to one of two treatment groups: one which will receive Pexa-Vec followed by sorafenib and one which will receive sorafenib alone.

"Our primary focus at this time is to execute a well-run, successful clinical trial."

The trial will be conducted at about 140 sites across the world, including North America, Asia, Australia, and Europe.

SillaJen CEO Eun Sang Moon said: "We are pleased to be initiating this multinational Phase III trial for Pexa-Vec-an oncolytic immunotherapy, which demonstrated antitumour activity in Phase II clinical trials for liver cancer.

"Our primary focus at this time is to execute a well-run, successful clinical trial, and we believe that the SPA that we have in place with the FDA will allow us and our global partners a clear path to approval for Pexa-Vec."

The company has also reached an agreement with the US Food and Drug Administration (FDA) on a special protocol assessment (SPA) for this Phase III trial.

The trial’s primary objective will be to determine the overall survival of patients treated with Pexa-Vec, followed by sorafenib versus sorafenib alone.

Secondary objectives will include safety and assessments for tumour responses between the two groups, as measured by time to progression, progression-free survival, overall response rate, and disease control rate.

Pexa-Vec is the most advanced product candidate from the company’s SOLVE (Selective Oncolytic Vaccinia Engineering) platform.