Vical begins trial of DNA vaccine for bird flu

The double-blind, placebo-controlled trial will evaluate safety, tolerability and immune responses in up to 60 healthy volunteers aged 18 to 45 at two US clinical sites.

According to the company, the currently stockpiled pandemic influenza vaccines primarily generate antibody responses against a specific strain, and have a limited shelf life because they cannot be stored frozen.

“Our pDNA vaccine is designed to provide T-cell and antibody immune responses for broad cross-strain protection, and if frozen, would offer improved storage and deployment. This trial is also important because it marks the first time in humans for our Vaxfectin adjuvant, which has potential applications with both pDNA vaccines and conventional protein-based vaccines,” said Vijay Samant, Vical's president and CEO.

Vical's vaccine contains three individual DNA plasmids encoding consensus sequences of two highly-conserved influenza virus proteins – nucleoprotein and ion channel protein – plus a hemagglutinin surface protein from the H5N1 influenza virus strain, A/Vietnam/1203/04. The combination is designed to elicit both T-cell and antibody immune responses against emerging strains of influenza virus that have the potential to cause a pandemic.

A monovalent pDNA vaccine encoding only the H5 protein will also be tested. Both vaccines are formulated with the company's Vaxfectin adjuvant, which has demonstrated effectiveness with a variety of pDNA vaccines in multiple animal models. It has also demonstrated dose-sparing and immune-enhancing ability with a conventional seasonal influenza vaccine in animals.

Vical's pandemic influenza program goal is to design a vaccine that can be developed and manufactured quickly and safely without handling the infectious organism, provide cross-strain protection, and be stockpiled longer and in less restrictive conditions than conventional vaccines.