Vical Incorporated, a company researches and develops biopharmaceutical products based on its patented DNA delivery technologies, announced the initiation of a phase 1 clinical trial with its novel DNA vaccine for anthrax.

The trial will test the vaccine in up to 52 healthy adult volunteers for safety and immune responses. Successful completion of this trial could lead to potential larger trials to support marketing approval under the US FDA's Animal Rule, and could encourage development of other vaccines using the same technology.

The trial is being supported by the US National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) at two NIAID-funded Vaccine and Treatment Evaluation Units (VTEUs).

"Dosing of all subjects should be completed by early 2005," said David C Kaslow, Vical's chief scientific officer, "providing an opportunity by early next year to evaluate interim results. Both the safety and immunogenicity results from this trial should provide critical information required to advance toward our objective of developing a well-tolerated, highly efficacious anthrax vaccine."

The multi-centre, randomized, double-blind, placebo-controlled, dose-escalating clinical trial is designed to evaluate the safety and immunogenicity of Vical's prophylactic, cationic lipid-formulated, bivalent plasmid DNA anthrax vaccine. Each subject will receive three doses of the vaccine or placebo at doses from 0.2 mg to 2.0 mg. All subjects will be followed for up to one year. Although the primary endpoint of the trial is safety, secondary endpoints in this trial include the immunogenicity of the vaccine at the various doses and regimens.

"This clinical trial brings a state-of-the-art DNA vaccine optimized for eliciting antibodies to the proof-of-concept stage for the first time in man," added Dr. Kaslow. "In addition to addressing a pressing public need to counter bio-terrorism, we expect to confirm the more general ability of lipid-formulated DNA vaccines to elicit biologically relevant antibody responses in humans, which would lead to a substantial broadening in the range of potential vaccine applications."

Anthrax is a serious infectious disease most frequently occurring in hoofed mammals, but also affecting humans exposed to the spore-forming Bacillus anthracis.