Inovio Biomedical Demonstrates Protective Immune Responses Against Novel H1N1 (2009) Influenza Virus In Ferret Model

Main Category: Swine Flu
Also Included In: Flu / Cold / SARS;  Public Health;  Immune System / Vaccines
Article Date: 06 Oct 2009 - 3:00 PDT

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Inovio Biomedical Corporation (NYSE Amex:INO), a leader in DNA vaccine design, development and delivery, announced that a combination of its synthetic consensus (SynConTM) H1N1 influenza vaccine candidates achieved protective antibody responses against the novel pandemic influenza A/H1N1 (2009) in 100% of tested ferrets. The ferret model is widely considered to be the most representative of human influenza; achieving in ferrets a level of antibody titers commonly associated with protection in humans is a critical milestone in influenza vaccine development. Dr. Niranjan Y. Sardesai, Inovio's Sr. VP, Research and Development, presented this data at the Vaccine 3rd Global Congress in Singapore in a presentation entitled, "Development of Universal SynCon™ DNA Vaccines for Pandemic and Seasonal Flu."

Following promising results in mice and pigs with SynCon™ H1N1 DNA vaccine candidates, as referenced in previous news releases, in this study Inovio scientists immunized ferrets with a formulation of H1N1 DNA vaccine candidates. They then tested the ferrets' serum for hemagglutination inhibition (HI) responses against one of the 2009 pandemic H1N1 strains, A/H1N1/Mexico/InDRE4487/2009.

HI measurements from the blood of vaccinated animals are used to assess the generation of protective antibody responses. Generating an antibody titer of 1:20 is generally regarded as a positive vaccine response, with a titer of 1:40 or higher in the blood of vaccinated subjects generally associated with protection against influenza in humans.

In this experiment, a single vaccination showed induction of positive immune responses in 78% (7 of 9) of ferrets, with a mean HI titer of 1:42. After two booster shots, 100% of immunized ferrets had HI titers greater than 1:40, with the mean titer rising to 1:390.

Dr. Sardesai stated in his presentation, "Achieving positive data from the important ferret model is a vital addition to the positive mice and swine data we already reported for our H1N1 SynCon™ DNA vaccine candidates. Together with our previously published H5N1 avian flu virus data, which highlighted the vaccine's cross-reactivity and broad immunogenicity across unmatched strains and included protection data in mice, ferrets, and non-human primates, these new H1N1 results further demonstrate the potential to protect against new strains of influenza that do not specifically match the vaccine - unlike conventional vaccines, which are strain-specific and usually provide limited protection against emerging, divergent strains of influenza."

Dr. J. Joseph Kim, Inovio's CEO, said, "This is another important step on our development path toward a universal influenza vaccine, which is intended to be a proactive rather than reactive approach to addressing both seasonal and pandemic strains. The beauty of our approach is that we can design universal DNA vaccines with broad protective capabilities against known and unknown strains. Our H1N1 vaccine candidates have achieved the desired outcomes in several relevant animal models against multiple unmatched virus strains. We are advancing our program with H1N1 as well as for the H2, H3 and H5 sub-types that would also be components of a universal vaccine. To this end, we have initiated cGMP clinical product manufacturing of our H1N1 SynCon™ vaccine candidate."

About Inovio's SynConTM Universal Influenza Vaccines

Inovio is focused on developing DNA-based influenza vaccines able to provide broad protection against known as well as newly emerging, unknown seasonal and pandemic influenza strains. Using its SynCon™ process, Inovio's scientists designed DNA vaccines targeting an optimal consensus of HA, NA, and NP proteins derived from multiple strains of the sub-types H1N1, H2N2, H3N2, and H5N1. These influenza sub-types have been responsible for the majority of seasonal and pandemic influenza outbreaks of the last century.

Conventional vaccines are strain-specific and have limited ability to protect against genetic shifts in the influenza strains they target. They are therefore modified annually in anticipation of the next flu season's new strain(s). If a significantly different, unanticipated new strain emerges, such as the current swine-origin pandemic strain, then the current vaccines provide little to no protective capability. In contrast, Inovio believes that its design approach to characterize a broad consensus of antigens across variant strains of each influenza sub-type creates the ability to protect against new strains that have common genetic roots, even though they are not perfectly matched. By formulating a single vaccine with some or all of the key sub-types, protection may be achieved against seasonal as well as pandemic strains such as swine flu or pandemic-potential strains such as avian influenza.

Source
Inovio Biomedical Corporation

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