Vical's Vaxfectin Enhances Preclinical Immune Responses to Baxter's Cell Culture-Derived Influenza Vaccines

Vical Incorporated

today announced the online publication1 of Baxter's (Baxter International Inc.)

preclinical evaluations of Vical's Vaxfectin® adjuvant in combination with Baxter's cell culture-derived seasonal and pandemic influenza vaccines. Simple addition of Vaxfectin® to the influenza vaccines substantially increased both antibody and T-cell responses compared with nonadjuvanted vaccines in mice and guinea pigs. Baxter's evaluations of Vaxfectin®-adjuvanted vs. nonadjuvanted vaccines showed: Hemagglutination inhibition (HI) antibody titers up to 20X higher against each of the three influenza virus strains in a trivalent seasonal vaccine; HI antibody titers up to 8X higher against the H5N1 influenza virus strain in a monovalent pandemic vaccine; T-cell frequencies up to 10X higher for each of the trivalent seasonal vaccine strains; and T-cell frequencies up to 22X higher for the monovalent H5N1 strain. "Seasonal influenza vaccines continue to provide suboptimal levels of efficacy, particularly in the elderly, and a good adjuvant could provide a meaningful boost in immunogenicity," said Larry R. Smith, Ph.D., Vical's Vice President of Vaccine Research and lead author on the paper. "In the pandemic influenza setting, particularly for emerging strains such as the current H7N9 outbreak in Asia, new vaccines become available initially only in very