The dose-sparing ability could be critical in extending limited vaccine supplies to protect a great number of people in the event of a pandemic influenza outbreak, according to the company.
In the study, mice were vaccinated with US government-supplied H5N1 vaccine, with or without the Vaxfectin adjuvant, and evaluated for antibody responses by enzyme-linked immunosorbent assay (ELISA). After a single injection, the Vaxfectin-formulated vaccine yielded five-fold higher antibody responses at the same dose as the unformulated vaccine, and comparable or better antibody responses at one-third the dose of unformulated vaccine.
After a second injection, the Vaxfectin-formulated vaccine yielded nine-fold higher antibody responses at the same dose as the unformulated vaccine, and five-fold better antibody responses at one-third the dose of the unformulated vaccine.
Alain Rolland, senior vice president of product development, Vical, said: “We continue to expand the database demonstrating the dose-sparing and immunogenicity-enhancing capabilities of our Vaxfectin adjuvant, as well as its potential safety and tolerability advantages. Our lead DNA vaccine candidate against H5N1 influenza, formulated with Vaxfectin, provided 100% protection in mice and ferrets against lethal challenges, and is currently in Phase I human testing. We are encouraged by the recent influenza and measles data, and look forward to further evaluation of Vaxfectin.”