Inovio Biomedical announces positive test results of its consensus influenza vaccines

Inovio Biomedical Corporation (NYSE Amex:INO), a leader in DNA vaccine design, development and delivery, announced today that a combination of its synthetic consensus H1N1, H2N2, H3N2, and H5N1 influenza vaccine candidates achieved protective antibody responses against several different influenza sub-types and strains in ferrets. In addition, ferrets immunized with Inovio’s SynCon^TM universal flu vaccine combinations were 100% protected against death and sickness in a challenge with the A/H1N1 (2009) swine-origin influenza. Dr. Niranjan Y. Sardesai, Inovio’s SVP, Research and Development, presented this data at the Influenza Congress USA 2009 in Washington, DC, in a presentation titled, “Development of Universal SynCon™ DNA Vaccines for Pandemic and Seasonal Influenza.”

Inovio previously reported that its consensus H5N1 and H1N1 vaccine candidates induced protective immune responses in ferrets and other animal models against multiple strains of H5N1 (clade 1 and 2) and H1N1 viruses with pandemic potential. The studies reported here mark one of the first demonstrations of a vaccine formulation proving effective against a broad panel of influenza viruses representing seasonal and pandemic influenza strains.

Dr. J. Joseph Kim, Inovio’s President and CEO, said, “Inovio is proud to be one of the first organizations to demonstrate a vaccine capable of providing protection against a broad set of unmatched influenza sub-types and strains, both seasonal and pandemic. If we can achieve similar outcomes in humans, this universal vaccine concept would have the potential to shift the current reactive paradigm of influenza vaccine design, manufacturing, and inoculation – a paradigm unrealistically challenged every year to correctly match key emerging strains, manufacture the vaccine, and inoculate people in an eight to 12 month cycle – to one that preemptively provides broader protection without having to match the minor and major changes in influenza that create new seasonal and pandemic strains. Such a shift would provide tremendous health and economic benefits worldwide.”

In these studies the researchers immunized ferrets with either a vaccine formulation targeting only H1N1 viruses (seasonal and pandemic) or a universal vaccine formulation targeting H1N1, H2N2, H3N2, and H5N1 viruses. Ferrets are considered to be the most relevant animal model for influenza vaccine development. The first test was a measurement of hemagglutination inhibition (HI) responses: blood taken from vaccinated animals was tested against different influenza strains for the level of anti-HA (e.g. H1, H2, etc.) protective antibodies in the blood serum. A measured “antibody titer” of 1:20 is generally regarded as a positive vaccine response; 1:40 is generally associated with protection against influenza in humans.

Mean HI titers for both the H1N1 and universal vaccine groups were measured to be significantly greater than 1:40 against 2009 H1N1 pandemic strains and seasonal H1N1 strains (ranging from 1:104 to 1:747). Moreover, the universal vaccine group also generated strong mean HI titers against the H3N2 strains (> 1:80). Testing of HI titers against H2N2 viruses is on-going.

Both sets of ferrets were subsequently challenged with the A/H1N1 Mexico/InDRE/4487/2009 virus. 100% of the vaccinated ferrets in both the H1N1 and universal vaccine groups survived the swine flu A/H1N1 challenge. In contrast, 75% of the animals in an unvaccinated control group died by day 10 following the challenge. The vaccinated animals were also protected from morbidity, as judged by their negligible average loss in body weight of less than 7% through the challenge period, whereas the unvaccinated animals lost as much as 17% of their body weight.

Dr. Sardesai stated in his presentation, “We continue to build an impressive and compelling set of evidence validating our universal influenza vaccine concept. This data showing broadly cross-protective antibody titers against multiple sub-types and unmatched strains of seasonal and pandemic influenza adds to our previously announced H5N1 avian flu and H1N1 pandemic flu virus data that highlighted similarly compelling protective results in mice, ferrets, and non-human primates. The consistently positive test results we are achieving with our consensus influenza vaccines are very encouraging.”