Vical Incorporated announced the publication in the online edition of Vaccine1detailed data from two phase-1 trials of the company's Vaxfectin-adjuvanted DNA vaccines for H5N1 (avian-origin) influenza, demonstrating the potential of DNA vaccines for rapid deployment in future pandemics.

"Our phase-1 results clearly demonstrated the ability of DNA vaccines against H5N1 avian-origin influenza to achieve antibody responses in the same range as conventional vaccines," said Larry Smith, Vical's vice president of Vaccine Research and the lead author on the paper. "These trials are key to expanding the use of our Vaxfectin adjuvant as they provided its first successful safety evaluations in humans. We seized the opportunity to further demonstrate the potential of our technology during the 2009 H1N1 pandemic influenza outbreaks. We completed successful pilot lot production and initiated animal immunogenicity testing of a Vaxfectin-adjuvanted DNA vaccine for H1N1 pandemic influenza before conventional vaccine manufacturers even received the seed virus needed to start production. We published these data in late 2009, and expect to begin a US government-funded phase-1 clinical trial of our H1 pandemic influenza vaccine soon."

The double-blind, placebo-controlled, dose-escalation H5N1 phase-1 trials were conducted in approximately 100 healthy volunteers age 18 to 45 at three US clinical sites. The trials were designed to assess safety and immunogenicity following vaccination, and to evaluate monovalent and trivalent Vaxfectin-formulated H5N1 pandemic influenza DNA vaccines at various doses. The vaccines were well-tolerated in the trial, and induced antibody responses and T-cell responses against a matching strain of influenza virus, and cross-clade antibody responses against different strains. Highlights include – H5 antibody responses predictive of protection in up to 67 per cent of evaluable subjects at higher doses, in the same range as published protein-based H5 vaccine results; H5 antibody responses that persisted in a majority of responders through end of study at Day 182, suggesting potentially durable protection; antibody responses against H5 influenza virus strains from two different clades, suggesting protection against emerging strains that may not match the vaccine; persistent H5 T-cell responses for at least six months in 75 to 100 per cent of evaluable subjects in the various monovalent cohorts, offering broader potential protection than antibodies alone; antibody and/or T-cell responses against one or more antigens in 72 per cent of subjects in trivalent cohorts, including specific responses against conserved influenza virus proteins; no significant safety issues observed at any of the vaccine doses tested, clearing the path for additional human trials of Vaxfectin-adjuvanted vaccines.

Vical researches and develops biopharmaceutical products based on its patented DNA delivery technologies for the prevention and treatment of serious or life-threatening diseases.