Vical’s West Nile virus vaccine gains positive phase I results

Vical announced that in the clinical trial, a West Nile virus (WNV) vaccine candidate administered using Vical’s proprietary DNA delivery technology was safe and well tolerated. It produced neutralizing antibody WNV-specific responses in all 11 healthy volunteers who returned for follow-up testing after completing the three-dose vaccination schedule.

West Nile virus belongs to a group of disease-causing viruses known as flaviviruses that are usually spread by ticks or mosquitoes. WNV was first isolated in Uganda in 1937. It was found for the first time in 1999 in the New York City area and subsequently spread to other parts of the US, and by 2004 had been found in birds and mosquitoes in every state except Alaska and Hawaii.

According to the US Centers for Disease Control and Prevention (CDC), WNV caused 2,949 cases of disease and 116 deaths in the US in 2005.

“This vaccine was previously shown to be highly immunogenic in animal studies, and the high rate of seroconversion in humans, as measured in this study by neutralizing antibody titers, adds to the growing body of evidence demonstrating immunogenicity with DNA vaccines in humans as well,” said Dr David Kaslow, Vical’s chief scientific officer.

“Furthermore, the data encourage investigation of vaccines against diseases caused by other flaviviruses such as yellow fever, Japanese encephalitis, and dengue, as well as other diseases for which antibody responses may be protective.”

The phase I, open-label clinical trial study was sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), and conducted at the NIH Clinical Center.