Inovio commences immunization in U.S. Phase I clinical trial of SynCon H5N1 influenza DNA vaccine

Inovio Pharmaceuticals, Inc.Jun 15 2010

Inovio Pharmaceuticals, Inc. (NYSE Amex:INO), a leader in the development of therapeutic and preventive vaccines against cancers and infectious diseases, announced today that it has immunized its first subject in a U.S. Phase I clinical trial to evaluate its SynCon™ H5N1 (avian) influenza DNA vaccine, VGX-3400X. This H5N1 vaccine study represents the first step in demonstrating Inovio's novel universal influenza vaccine approach, which aims to bypass the current requirement for annual strain and subtype-specific influenza vaccines by developing a single vaccine to potentially protect against all strains within multiple targeted subtypes, such as H5N1 and H1N1, posing risk to humans.

“Heterosubtypic Protection against Pathogenic Human and Avian Influenza Viruses via In Vivo Electroporation of Synthetic Consensus DNA Antigens”

This dose escalation study is designed to test the safety and immunogenicity of VGX-3400X. VGX-3400X consists of three distinct DNA plasmids containing a universal consensus hemagglutinin (HA) antigen derived from different H5N1 flu viruses; a universal consensus neuraminidase (NA) antigen encompassing different N1 subtypes such as H5N1 and H1N1; and a universal consensus nucleoprotein (NP) fused to a small portion of the m2 protein (m2E), both also encompassing N1-based viruses. The clinical trial will be conducted at two sites in the U.S. Thirty healthy subjects will be enrolled in three dose groups of 0.2 mg, 0.67 mg, and 2.0 mg of each plasmid delivered via Inovio's proprietary electroporation technology. The primary objectives are to assess safety and tolerability. The secondary objective is to measure antigen-specific antibody and cellular immune responses, in particular hemaglutination inhibition (HI) responses, i.e. a measure of protection, against multiple strains of H5N1 influenza. The company expects to report study results in Q1 2011.

Inovio's SynCon^TM universal influenza vaccine approach provides "universality" on two levels: within and across different subtypes. SynCon^TM DNA vaccine "constructs" are designed to provide broad cross-reactive protection against the many existing and potential new strains within each influenza subtype, such as H5N1. Across subtypes, the universal influenza vaccine approach provides protection by combining SynCon^TM DNA vaccine constructs for targeted subtypes currently posing risk to humans (i.e. H1N1, H2N2, H3N2, and H5N1) to form a single combination vaccine. Cross-reactive protection against multiple unmatched strains has been established in previously reported animal studies and will now be assessed in this Phase I clinical study. Success in this clinical study would allow advancement into clinical studies of SynCon^TM influenza DNA vaccines encompassing H5N1 and H1N1, and subsequently additional subtypes, to further assess the universal influenza vaccine approach in humans.

Dr. J. Joseph Kim, Inovio's President and CEO, said: "We have already demonstrated protection against multiple unmatched as well as newly emergent strains using combination SynCon™ vaccines for different influenza subtypes in multiple pre-clinical studies. These studies also indicated that our SynCon™ vaccines induced antigen-specific immune responses far exceeding levels that have been correlated with protection in humans. We look forward to human data from this trial and advancing this potentially paradigm-shifting vaccine approach."

As previously published in PLoS ONE, a peer-reviewed, online publication, in an article entitled, "Heterosubtypic Protection against Pathogenic Human and Avian Influenza Viruses via In Vivo Electroporation of Synthetic Consensus DNA Antigens," Inovio's SynCon™ H5N1 (avian) influenza DNA vaccine has been shown to provide broad protection against divergent strains of H5N1 influenza in mouse, ferret, and non-human primate models. Responses in all three species demonstrated the ability of SynCon™ antigens to induce antibodies capable of providing cross-protection from divergent strains of the H5N1 subtype. In additional testing, ferrets and mice vaccinated with the SynCon™ antigens were 100% protected from a lethal influenza challenge, with a concomitant significant reduction in viral shedding and disease progression in the vaccinated animals.

While this first human clinical study is focused on the H5N1 based vaccine, Inovio has also previously demonstrated the efficacy of other components of its SynCon™ universal vaccine in relevant animal models. In pre-clinical studies of Inovio's SynCon™ H1N1 flu vaccine, vaccinated mice were all protected from the unmatched 1918 "Spanish" H1N1 influenza and did not suffer weight loss. Additionally, ferrets immunized with the vaccine were 100% protected against death and sickness in a challenge with the unmatched A/H1N1 (2009) swine-origin influenza.