Date: 8/28/2007 6:30:00 AM

SAN DIEGO, Aug. 28 /PRNewswire-FirstCall/ -- Vical Incorporated (Nasdaq: VICL) today announced the enrollment of the first subject in its Phase 1 trial of the company's Vaxfectin(TM)-formulated plasmid DNA (pDNA) pandemic influenza vaccine. The double-blind, placebo-controlled trial will evaluate safety, tolerability and immune responses in up to 60 healthy volunteers age 18 to 45 at two U.S. clinical sites.

"We have designed a promising pandemic influenza vaccine and demonstrated its effectiveness against a highly lethal H5N1 challenge in ferrets, the best available animal model," said Vijay B. Samant, Vical's President and Chief Executive Officer, "and we have now begun testing in humans. 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(TM) adjuvant, which has potential applications with both pDNA vaccines and conventional protein-based vaccines."

Vical's vaccine contains three individual DNA plasmids encoding consensus sequences of two highly-conserved influenza virus proteins -- nucleoprotein (NP) and ion channel protein (M2) -- plus a hemagglutinin (HA) 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(TM) 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.

Pandemic Influenza Vaccine Background

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. Vical systematically tested prototype vaccines using a range of viral antigens to determine the optimum combination of conserved and variable targets. The company then systematically tested different formulations for maximum efficacy at the lowest possible dose. Initial virus challenge studies at Vical with Vaxfectin(TM)-formulated vaccines encoding NP, M2 and HA demonstrated significant protection in mice against H1N1 and H3N2 strains of human influenza. Subsequent studies at St. Jude Children's Research Hospital demonstrated complete protection with a single dose of the trivalent vaccine against a lethal challenge in ferrets with the highly pathogenic A/Vietnam/1203/04 (H5N1) influenza virus strain. Funding for the preclinical development was provided under a previously-announced grant from the National Institutes of Health.

"We are excited to advance our pandemic influenza DNA vaccine program into initial human testing," said Larry R. Smith, Ph.D., Vical's Vice President of Vaccine Research, "and to conduct our first human tests with the novel Vaxfectin(TM) adjuvant, which was designed for pDNA vaccines but also has demonstrated significant dose-sparing and immune-enhancing results with the sanofi pasteur trivalent inactivated influenza vaccine in animals."

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 http://www.vical.com.

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 influenza 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 influenza; whether development of an avian influenza vaccine would lead to development of a seasonal influenza vaccine; whether the influenza 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 influenza vaccine or any other product candidates; whether Vical or its collaborative partners will succeed in marketing the influenza 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.

    Contacts:    Investors:                       Media:
                 Alan R. Engbring                 Susan Neath
                 Vical Incorporated               Porter Novelli Life Sciences
                 (858) 646-1127                   (619) 849-6007
                 Website:  http://www.vical.com


SOURCE  Vical Incorporated
    -0-                             08/28/2007
    /CONTACT:  Investors, Alan R. Engbring of Vical Incorporated,
+1-858-646-1127; or media, Susan Neath of Porter Novelli Life Sciences,
+1-619-849-6007, for Vical Incorporated/
    /Web site:  http://www.vical.com/
    (VICL)

CO:  Vical Incorporated
ST:  California
IN:  HEA MTC
SU:  TRI

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