Vical Incorporated (Nasdaq: VICL) today announced that a single injection of the company's lead avian influenza (flu) DNA vaccine candidate provided 100% protection in ferrets against lethal challenge with a highly virulent H5N1 virus (Vietnam/1203/2004). Conventional vaccines under development for avian flu typically have required two or more doses in humans, even with novel adjuvants, to produce the immunogenicity levels expected to provide protection.

The company had previously demonstrated that two doses of the vaccine candidate provided 100% protection in mice and ferrets against lethal challenges with H5N1 virus. A single-dose vaccine regimen could prove beneficial during a pandemic, both in extending vaccine supply to protect a greater number of people, and in achieving protective immune responses as quickly as possible. The studies were part of the company's program to develop a DNA vaccine to protect humans against emerging strains of flu virus that have the potential to cause a pandemic. Vical's three-component DNA vaccine candidate encodes two highly-conserved influenza virus proteins -- nucleoprotein (NP) and ion channel protein (M2) -- plus the H5 avian influenza virus surface protein, and is formulated with the company's patented Vaxfectin(TM) adjuvant.

"We are excited by the recent advances in our pandemic flu vaccine development program," said Vijay B. Samant, President and Chief Executive Officer of Vical. "Earlier this week, we presented data from mouse studies demonstrating the dose-sparing ability of our Vaxfectin(TM) adjuvant when used with conventional flu vaccines. Today we presented data from ferret studies demonstrating the ability to provide complete protection with a single dose of our Vaxfectin(TM)-formulated avian flu DNA vaccine. Our goal is to advance into human testing with this program as quickly as possible, both to provide a potential defense against a pandemic outbreak and to explore the potential for a seasonal flu vaccine using a similar approach."

Larry R. Smith, Ph.D., the company's Vice President of Vaccine Research, presented the data Friday at the annual meeting of the Second International Conference on Influenza Vaccines for the World (Vienna, October 18 - 20). Financial support was provided under previously-announced grants from the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH). All lethal challenge testing was conducted in BSL-3 facilities at St. Jude Children's Research Hospital under the direction of Richard J. Webby, Ph.D.

About Vical

Vical researches and develops biopharmaceutical products based on its patented DNA delivery technologies for the prevention and treatment of serious or life-threatening diseases. Potential applications of the company's DNA delivery technology include DNA vaccines for infectious diseases or cancer, in which the expressed protein is an immunogen; cancer immunotherapeutics, in which the expressed protein is an immune system stimulant; and cardiovascular therapies, in which the expressed protein is an angiogenic growth factor. The company is developing certain infectious disease vaccines and cancer therapeutics internally. In addition, the company collaborates with major pharmaceutical companies and biotechnology companies that give it access to complementary technologies or greater resources. These strategic partnerships provide the company with mutually beneficial opportunities to expand its product pipeline and address significant unmet medical needs. Additional information on Vical is available at vical/.

This press release contains forward-looking statements subject to risks and uncertainties that could cause actual results to differ materially from those projected, including: whether results in mouse and ferret studies will be predictive of results in human studies; whether Vical or others will continue development of the pandemic influenza DNA vaccine candidate; whether H5N1 or other strains of avian flu will emerge as pandemic threats; whether the company's DNA vaccine candidate will be effective in protecting humans against H5N1 or other strains of avian flu; whether development of an avian flu vaccine would lead to development of a seasonal flu vaccine; whether the flu vaccine or any other product candidates will be shown to be safe and effective; the timing, nature and cost of clinical trials; whether Vical or its collaborative partners will seek or gain approval to market the flu vaccine or any other product candidates; whether Vical or its collaborative partners will succeed in marketing the flu vaccine or any other product candidates; and additional risks set forth in the company's filings with the Securities and Exchange Commission. These forward-looking statements represent the company's judgment as of the date of this release. The company disclaims, however, any intent or obligation to update these forward-looking statements.

Vical Incorporated
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