Inovio Biomedical Corporation, a leader in DNA vaccine discovery, development and delivery, announced preclinical data from two studies of influenza DNA vaccines designed using its SynCon technology. The data indicated that the consensus H1N1 and H5N1 influenza vaccines achieved significant increases in immune response and provided protection against influenza virus strains not genetically matched to the vaccine, which is a requirement for conventional vaccines to be effective and a limitation to their effectiveness, i.e. they can't protect against newly emerging strains. Dr Niranjan Sardesai, senior VP, Research & Development of VGX Pharmaceuticals, which merged with Inovio Biomedical on June 1, 2009, presented this data at the 12th Annual Meeting of the American Society of Gene Therapy held in San Diego, California, May 27 to 30, 2009, in a presentation entitled, 'Improved Challenge Outcome Following Intradermic Vaccination by Electroporation of a Consensus H5N1 Influenza DNA Vaccine in Non-Human Primates'.
In the first study, the scientists immunized non-human primates with a consensus H5N1 avian influenza vaccine (VGX-3400). Delivered using the Company's in vivo electroporation device, the vaccine achieved high levels of protective antibody titers against unmatched clade 1 and multiple unmatched clade 2 H5N1 viruses. The animals were then challenged with the unmatched A/Vietnam/1203/04 strain. There was a significant reduction in average viral load (amount of virus in the blood stream) and decreased symptoms of disease in all the vaccinated animals compared to unvaccinated controls. Animals vaccinated by the intradermal route had a greater than 10,000-fold reduction in average viral load compared to untreated controls, an unprecedented result in comparative studies with similar animal models. These results were recently published in the May issue of the Journal of Virology.
In the second study, the scientists immunized mice with the SynCon H1HA consensus DNA vaccine. They then challenged the mice with the unmatched H1N1 virus that caused the 1918 Spanish flu. This virus caused the most devastating pandemic of the last century, killing over 40 million people worldwide. While all the control mice died by day 8 after being challenged with a lethal dose of the virus, all the animals vaccinated with the consensus H1HA vaccine survived (100 per cent protection) to the end of the experiment. In addition to measuring survival, the researchers observed significant protection from infection-associated morbidity in the H1HA immunized mice.
Dr Sardesai stated, "Influenza viruses mutate and develop multiple divergent strains very rapidly, allowing them to potentially escape protection afforded by existing vaccines. On the other hand, developing influenza vaccines effective against these newly emerging, or genetically unmatched, strains has been challenging. These animal data are encouraging and suggest that we could effectively cross-protect against unmatched influenza strains, even against a pandemic virus such as the one that killed millions of people in 1918. We are now testing our SynCon H1N1-targeted vaccines against the newly emergent swine-origin influenza A (H1N1)."
Dr J Joseph Kim, now Inovio's chief executive officer, said, "The ability to universally protect people from influenza strains that are not exactly like the ones that make up the existing vaccines we have would be an important contribution to modern medicine. We are enthusiastic about the potential of our vaccine approach and results to date, and we have filed an IND for VGX-3400, a candidate vaccine targeting avian influenza H5N1. We look forward to moving Inovio's first influenza program into the clinic."
VGX Pharmaceuticals, which merged with Inovio Biomedical on June 1, 2009, and its collaborators at the University of Pennsylvania developed the Company's novel SynCon technology to design DNA-based vaccines with the capability to provide protection against unmatched sub-types and strains of pathogens. Using the SynCon technology, the scientists created universal influenza vaccines targeting both seasonal and avian influenza strains. VGX Pharmaceuticals created a set of SynCon DNA vaccines based on influenza HA, NA, and NP proteins from strains H1N1, H2N2, H3N2, and H5N1. This designer approach can potentially allow Inovio to rapidly develop a universal influenza vaccine containing DNA targeting all these strains simultaneously by formulating the individual component plasmids together against these target strains which make up the majority of seasonal and pandemic influenza.
Inovio Biomedical is engaged in the discovery, development, and delivery of a new generation of vaccines, called DNA vaccines, focused on cancers and infectious diseases.