US-based Inovio Pharmaceuticals has started a Phase I clinical trial to test the safety, tolerability and immunogenicity of its experimental therapeutic vaccine (INO-8000/VGX-6150) in chronically hepatitis C virus (HCV) infected patients.

VGX International, a subsidiary of Inovio, is providing funds and carrying out the trial of the immunotherapy at several sites in South Korea as part of a collaborative development agreement signed between Inovio and VGX International in 2011.

Eighteen subjects divided into three groups will be participating in the multi-centre, open-label, dose-escalating Phase I trial and they will be given four monthly vaccinations of 1mg, 3mg and 6mg doses of VGX-6150, respectively.

Patients with chronic HCV who failed previous standard of care therapy with pegylated interferon and ribavirin or triple therapy with standard of care and direct-acting antiviral agents like boceprevir or telaprevir will be enrolled in the trial.

During the trial, the effects of the HCV immunotherapy will be directly tested in patients who have previously failed standard drug therapies.

In the trial, both immunogenicity and virologic response will be assessed in addition to the safety and tolerability of VGX-6150, a SynCon multi-antigen DNA vaccine covering HCV genotypes 1a and 1b and targeting HCV nonstructural proteins 3 (NS3) and 4A (NS4A) as well as NS4B and NS5A proteins.

Inovio’s SynCon design is intended to provide broader protection against new mutations of a virus.

"Inovio’s SynCon design is intended to provide broader protection against new mutations of a virus."

VGX-6150 will be administered with Inovio’s proprietary CELLECTRA delivery device, which co-localises vaccine delivery with the applied electric field and operates under more effective constant-current EP parameters.

Starting in 2014, the company intends to assess the HCV vaccine in additional clinical studies.

In the preclinical studies, the company’s HCV immunotherapy has been shown to generate powerful T cell responses in the liver, which could help in clearing HCV-infected liver cells.

Inovio president and CEO Joseph Kim said more effective antiviral drugs have changed the prognosis for patients with hepatitis C. However, treatment failures remain and combination with an immunotherapeutic approach could make the difference for many patients.

"We look forward to entering the hepatitis C treatment arena, which is one of the fastest-developing markets in healthcare, with a projected value of $20bn by the end of the decade," Kim said.

Image: Electron micrographs of hepatitis C virus purified from cell culture. Photo: courtesy of TimVickers.