Inovio Pharmaceuticals’ Universal H7N9 DNA Vaccine Protects 100% Of Vaccinated Animals In Challenge Study
Inovio Pharmaceuticals, Inc. (NYSE MKT: INO) has announced that in a preclinical study of its influenza DNA vaccine against the virulent, newly emergent H7N9 flu virus, 100% of the vaccinated animals were protected against sickness and death when they were challenged with a lethal dose of H7N9 virus. The results from a study in mice demonstrated that Inovio’s vaccine generated not only hemagglutination inhibition (HAI)-based protection against the H7N9 virus but also strong T-cell responses. Inovio’s DNA vaccine created cellular immune responses that could reduce the severity of the infection in a person that acquires the virus and limit the spread of the virus in a pandemic setting. Detailed study results will be presented at an invited plenary session at the TEPIK/APACI International Influenza Symposium being held in Seoul, South Korea, on July 12, 2013.
Inovio researchers constructed a consensus DNA vaccine targeting the HA influenza antigen based on sequences collected from several infected H7N9 patients to create a vaccine that is broadly protective against all H7N9 strains. Inovio’s vaccine was administered in mice using its proprietary electroporation-based delivery technology twice, 3 weeks apart; the mice were then exposed to a lethal dose of A/Anhui/1/13 strain of H7N9 virus 4 weeks after the second vaccination. The challenge studies were conducted by Inovio’s collaborators at Canada’s National Microbiology Laboratory in Winnipeg. Results demonstrated that 100% of the vaccinated animals (n=10) remained healthy without any weight loss (a key indicator of health) and survived while all unvaccinated mice in the control group (n=10) had significant morbidity, including up to 30% weight loss, and died within 8 days of challenge.
This study showed for the first time that an H7N9 flu vaccine can protect against this newly emergent influenza subtype, with the added novelty that Inovio’s newly created universal “construct” for this subtype was not matched to the virus strain, suggesting the potential to provide protection against other mutated strains that would be expected to emerge within the H7N9 family of influenza. These results also show the speed at which Inovio can construct and test a DNA vaccine against a new virus or new subtype of a virus.
Dr. J. Joseph Kim, Inovio’s President and CEO, said, “We need truly preemptive, broad protection against multiple known and new strains within existing families of viruses. Furthermore, history has shown that new viruses and virus subtypes do periodically emerge – H7N9 being just one recent example – and speed in creating a new vaccine will be of the essence in pandemic situations. Inovio is proving its abilities on both counts. This new preclinical data further validates the power of Inovio’s DNA vaccines to induce antigen-specific antibody and T-cell responses, which we have also demonstrated across other medical conditions such as pre-cancerous lesions and HIV.”
Inovio previously reported that this newly developed H7N9 influenza DNA vaccine generated greater than 1:40 hemagglutination inhibition (HAI) titers in 100% of tested animals, with a geometric mean HAI titer of 1:130 against the A/Anhui/1/13 strain of H7N9 virus. This newly reported generation of strong T-cell immune responses tested by the ELISpot assay as well as the superb challenge data further demonstrates the power and potential of Inovio’s universal flu vaccine franchise.
Using Inovio’s synthetic consensus design approach the company has created universal DNA constructs for key virus clades (branches) within the Type A subtypes H1N1, H2N2, H3N2, and H5N1 as well as Type B. These constructs target multiple influenza antigens associated with influenza, including the most frequently changing antigen, HA. Inovio can mix and match these individual DNA plasmid constructs as desired to create vaccine candidates. Inovio has previously reported human data indicating protective immune responses against the subtypes H1N1 and H5N1.