Vical's Vaxfectin(R) Adjuvant Drives 200-Fold Increase in Antibody Responses With...

Vical's Vaxfectin(R) Adjuvant Drives 200-Fold Increase in Antibody Responses
With Sanofi-Pasteur Fluzone(R) Seasonal Influenza Vaccine

SAN DIEGO, Oct. 26, 2009 (GLOBE NEWSWIRE) -- Vical Incorporated (Nasdaq:VICL)
announced today the publication of two articles regarding the company's
Vaxfectin(R) adjuvant in a special issue of Vaccine.(1,2) One article
highlighted preclinical data showing Vaxfectin(R)'s improvement of performance
with Sanofi-Pasteur Fluzone(R) seasonal influenza vaccine; the other analyzed
how Vaxfectin(R) works.

"Vaxfectin(R) is a powerful new adjuvant for a broad range of infectious disease
and cancer vaccine applications," said Alain P. Rolland, Pharm.D., Ph.D.,
Vical's Executive Vice President of Product Development. "These latest data
expand our understanding of Vaxfectin(R)'s mechanism of action and the breadth
of its abilities as an adjuvant to increase antibody and/or T-cell responses. We
are currently evaluating Vaxfectin(R) with DNA-, protein- and peptide-based
vaccines both independently and with collaborators."

Vical authors Hartikka et al. demonstrated in mice that commercially acquired
Sanofi-Pasteur Fluzone(R) seasonal influenza vaccine formulated with the
company's patented Vaxfectin(R) adjuvant produced up to 200-fold higher antibody
responses and at least a 10-fold dose-sparing effect compared with unformulated
vaccine. Vaxfectin(R)-formulated vaccine also produced a more balanced T-helper
cell immune response than unformulated vaccine, suggesting the ability to
enhance vaccine effectiveness. In addition, a low ratio of Vaxfectin(R) to
vaccine was found to favor T-cell immune responses, while a higher ratio of
Vaxfectin(R) to vaccine was found to favor antibody immune responses. The
authors concluded that increased T-cell or antibody responses may be
preferentially induced by changing the Vaxfectin(R) to vaccine ratio.

Vical authors Shlapobersky et al. explored the mechanism of action of
Vaxfectin(R) when used in combination with a protein-based seasonal influenza
vaccine. They determined that the ratio of Vaxfectin(R) to protein changes the
particle size of the vaccine, which in turn modulates the profile of immune
response. The profile was determined both locally at the site of injection and
systemically in serum by analyzing a panel of biomarkers by gene expression
profiling. The authors concluded that some of these biomarkers may be useful in
tailoring the ratio of Vaxfectin(R) to vaccine to produce the optimal balance
between T-cell and antibody responses for specific applications.

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 www.vical.com.

The Vical Incorporated logo is available at
http://www.globenewswire.com/newsroom/prs/?pkgid=5768

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 Vical will enter into any collaborative agreements
for the development or commercialization of Vaxfectin(R)-formulated vaccine
candidates; whether Vical or others will pursue development of any
Vaxfectin(R)-formulated vaccine candidates; whether any vaccine candidates will
be safe and tolerable, or effective in eliciting immune responses; whether
results in mouse studies will be predictive of results in human studies; whether
formulation with Vaxfectin(R) will increase vaccine effectiveness or drive a
particular type of immune response; whether any product candidates will be shown
to be safe and effective in clinical trials; the timing, nature and cost of
clinical trials; whether Vical or its collaborative partners will seek or gain
approval to market the any product candidates; whether Vical or its
collaborative partners will succeed in marketing any 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.

(1) Hartikka J et al. Vaxfectin(R), a cationic lipid-based adjuvant
for protein-based influenza vaccines. Vaccine 2009; 27:6399 -6403.

(2) Shlapobersky M et al. Vaxfectin(R)-adjuvanted seasonal influenza
protein vaccine: Correlation of systemic and local immunological
markers with formulation parameters. Vaccine 2009; 27: 6404-6410.
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CONTACT: Vical Incorporated
Alan R. Engbring
(858) 646-1127
www.vical.com