Inovio Pharmaceuticals, Inc. (NYSE MKT: INO) today announced the release of preliminary clinical trial results by its collaborator ChronTech AS of their open label phase II clinical study of ChronVac-C®, ChronTech's vaccine to treat hepatitis C virus (HCV) infection. The study investigated the use of the ChronVac-C DNA vaccine administered with Inovio's MedPulserTM-DDS electroporation device followed by a drug regimen (ribavirin + PEG-interferon-a) in chronic HCV positive subjects. These initial results do not show a statistically significant difference so far between treatment outcomes of the vaccinated and non-vaccinated groups. The vaccinated group did display an excellent safety profile.
In this 29 patient phase II study, 17 patients were treated with two monthly vaccinations of ChronVac-C (500 ug) followed by interferon and ribavirin. In the control arm, 12 patients were treated with interferon and ribavirin alone. ChronTech has now made a first analysis 12 weeks after treatment. HCV viral load reduction or elimination is assessed by measuring HCV RNA levels. At treatment week 12, 71% of the pre-vaccinated group had less than 15 international units of HCV RNA compared to 58% in the non-vaccinated group; 65% were HCV RNA negative compared to 58% in the non-vaccinated group. There were no serious adverse events and the number of patients with moderate adverse events was statistically lower in the pre-vaccinated group than in the non-vaccinated group (p<0.05, Fishers exact test). There was no difference in mild adverse events between the groups.
In 2007, ChronTech initiated its phase I dose escalation (167, 500, 1500 mg) study using its ChronVac-C DNA vaccine targeting genotype 1a and NS3/4A antigens delivered with Inovio's MedPulser device. The treatment regimen of four vaccinations delivered with electroporation demonstrated transient reduction in viral load. In that study, a group of eight patients were subsequently treated with standard of care ribavirin plus PEG-interferon-a. Of this group, six patients (75%) achieved a complete early viral response (cEVR) and a sustained viral response (SVR), an encouraging result compared to typical medical observations of 40-50% response rates with the ribavirin-interferon drug regimen alone in genotype 1 patients. In contrast to the previous study, in this subsequent phase II study only two DNA vaccine administrations at the medium dose level used in the phase I study were used to assess the potential for a clinically meaningful result.
"The major hurdle to developing therapeutic vaccines for any disease area has been the inability to generate a meaningful level of functional T-cell response and, in the case of HCV, one that is directed to the liver. We have appreciated the opportunity in this collaboration to support ChronTech with our electroporation delivery technology and observe the impact of varying vaccine doses and regimens and their combination with standard of care on immune responses and HCV viral load," said Dr. J. Joseph Kim , Inovio's President and CEO.