West Nile Virus DNA Vaccine Enters Human Trial

SAN DIEGO -- Vical Incorporated announced today that initial human testing of an investigational vaccine targeting West Nile virus (WNV) has begun at the National Institutes of Health's (NIH) Clinical Center in Bethesda, Md. The vaccine, based on Vical's proprietary DNA delivery technology, was co-developed at the National Institute of Allergy and Infectious Diseases' (NIAID) Vaccine Research Center (VRC) and at Vical.  Vical manufactured research and clinical supplies of the vaccine, and has an option to exclusive commercialization rights.

Vical's president and CEO, Vijay B. Samant, said, "We are pleased with the continued progress under our collaboration with the NIH, with four vaccine programs that have now advanced to human clinical testing. Leveraging the inherent advantages of our DNA delivery technology, we have rapidly constructed vaccines and advanced them to human testing.  The development time and safety advantages of our technology may be critically important for emerging diseases, which often spread rapidly and are potentially life-threatening."

The WNV vaccine encodes two key surface proteins of the West Nile virus. A similar vaccine construct was shown in independent tests at the Centers for Disease Control and Prevention to protect horses from WNV after a single injection.  The trial will enroll 15 healthy adult volunteers, who will each receive three injections at approximately four-week intervals.  Subjects will be monitored for safety and immune responses against the encoded WNV proteins.

West Nile virus has been an increasing seasonal threat in the United States over the past several years, causing growing numbers of cases in birds, horses, and humans each summer.  The disease is spread by many species of mosquitoes, which carry the virus from reservoirs to humans.  Most infected people have no disease symptoms, and some have only mild symptoms.  But approximately one out of every 150 infected people develops serious disease symptoms of the central nervous system, such as headache, high fever, tremors, convulsions, numbness, vision loss, coma, and paralysis lasting several days to several weeks, potentially with some permanent neurological damage.  Most West Nile virus deaths are caused by encephalitis, a severe swelling of the

brain, or meningitis, a severe swelling of the membrane surrounding the brain and spinal cord.

Conventional vaccines, using whole killed West Nile virus, are available for horses and for some species of birds.  To develop a human vaccine using this approach, however, could require many years of further development and testing to provide sufficient proof of safety and effectiveness.

Source: Vical