Inovio Biomedical's First Proprietary DNA Vaccine Achieves 100% Protection Against Avian Flu in Pre-Clinical Testing

Business Wire, July 16, 2008

Results Suggest Experimental DNA Vaccine May Protect Against Multiple Seasonal and Pandemic Influenza Strains

SAN DIEGO -- Inovio Biomedical Corporation (AMEX:INO), a leader in enabling the development of DNA vaccines using a proprietary electroporation-based DNA delivery platform, announced today pre-clinical results from two proprietary plasmid DNA-based universal influenza vaccine candidates using the company's proprietary electroporation delivery technology and, specifically, a new intradermal device. In this study, 100% of the immunized mice given a lethal challenge of highly pathogenic H5N1 influenza virus (A/Vietnam/1203/04) survived and showed only minor weight loss.

The DNA vaccine design was based on a different influenza strain (H1N1) than the influenza strain used in the challenge, providing evidence that a universal vaccine based on conserved genes common to multiple strains of seasonal influenza and even potential pandemic influenza may have the possibility to provide widespread protection against such viruses. In collaboration with Vandalia Research Inc., Inovio also tested the use of fully synthetic linear expressing cassettes (LEC) to express the same antigens and achieved similar results. These results were presented by Dr. Michael Fons, VP Corporate Development, on July 15th at the Controlled Release Society 35th Annual Meeting and Exposition.

"We're enthusiastic about these very early results because today's strain-specific (homologous) influenza vaccines cannot provide universal protection against seasonal influenzas and potential pandemic influenza strains. Only a broad-spectrum (heterologous) influenza DNA vaccine, such as the one we're testing, would have the potential to provide protection against multiple known and unknown influenza strains. Our hope is that such a universal vaccine may one day replace the standard seasonal vaccine and provide protection against the generally inconvenient symptoms as well as the more severe effects, including death, that can result from seasonal and pandemic influenzas," said Inovio CEO Dr. Avtar Dhillon.

Current strain-specific influenza vaccines are designed to stimulate an immune response specific to a single influenza strain. Given that seasonal flu can rapidly mutate, such homologous vaccines may provide modest protection against variant influenza strains but cannot fully prevent the contagion from widely spreading and causing not only the familiar symptoms of the common cold but, in some cases, death. The major risk of pandemic influenza is that new virulent strains of influenza, such as the avian flu, which have never spread widely through a human population, would potentially result in harsher symptoms and widespread death because of the body's delay in naturally building immunity to the virus and the inability to develop and distribute in a timely manner a vaccine specific to that influenza strain.

The concept of a universal broad-spectrum vaccine is based on emerging scientific knowledge that "conserved" regions of the influenza genome are not under dramatic selective pressure to mutate. These genes and the antigens they express are common across most strains of influenza. This creates the possibility to develop heterologous influenza vaccines without knowing the genetic make-up of a future influenza strain that may have the potential to, for example, migrate from animals to man and pose pandemic risk.

This pre-clinical work involved two other technology advancements Inovio has been developing or co-developing:

1) Fully synthetic linear expressing cassettes (LEC), or linear constructs, represent a new type of carrier mechanism for the genes that comprise a DNA vaccine. Numerous clinical studies have provided evidence that DNA plasmids are inexpensive, safe, and effective for delivering DNA vaccines. LECs are a next generation of synthetic DNA constructs that are easier, faster and cheaper to make, while providing equivalent utility.

2) Inovio has developed a multi-product line of electroporation devices that can provide different electroporation parameters in different types of tissue. This pre-clinical work used a new intradermal device intended to deliver a DNA vaccine into skin rather than muscle, the tissue type that is the focus of Inovio's existing clinical studies. Delivering a vaccine into skin creates the potential for greater tolerability and would therefore make such a device more acceptable for prophylactic (preventive) vaccination.

About Inovio Biomedical Corporation

Inovio Biomedical (AMEX:INO) is focused on developing multiple DNA-based immunotherapies. Inovio is a leader in developing human applications of electroporation using brief, controlled electrical pulses to increase cellular uptake of a useful biopharmaceutical. Interim human data has shown that Inovio's DNA delivery technology, which is protected by an extensive patent portfolio covering in vivo electroporation, can significantly increase gene expression and immune responses from DNA vaccines. Immunotherapy partners include Merck, Wyeth, Vical, University of Southampton, Moffitt Cancer Center, the U.S. Army, National Cancer Institute, and International Aids Vaccine Initiative. Inovio and VGX Pharmaceuticals have announced a proposed merger. More information is available at www.inovio.com.