Vical Announces Key European Patent for TransVax(TM) Cytomegalovirus Vaccine

SAN DIEGO , April 14, 2011 (GLOBE NEWSWIRE) -- Vical Incorporated (Nasdaq:VICL) announced today the issuance of European Patent EP1587816, which extends coverage for TransVaxT, the company's first-in-class therapeutic DNA vaccine designed to prevent reactivation of latent cytomegalovirus (CMV) or introduction of CMV through donor cells or tissues in transplant recipients.

TransVaxT encodes the CMV glycoprotein B (gB) and phosphoprotein 65 (pp65) antigens, and is formulated with a poloxamer designed to enhance primarily a cellular immune response. Vical's TransVaxT vaccine has orphan drug designation for transplant patients. In September 2010 , Vical announced encouraging results from a completed Phase 2 trial of the TransVaxT vaccine in patients undergoing hematopoietic stem cell transplants. The company is currently in discussions with regulatory authorities to confirm the design of a planned Phase 3 trial which is expected to begin in the second half of 2011.

Past development by others of protein-based prophylactic CMV vaccines has focused on antibody-mediated immune responses against the CMV gB antigen, which has achieved up to 50% protective efficacy. The new '816 patent covers DNA vaccines containing codon-optimized versions of genes encoding gB and CMV pp65 antigens, formulated with the CRL-1005 poloxamer in-licensed by Vical . It adds to Vical's family of patents in key geographic regions based on the company's discovery that administering genetic sequences such as DNA or RNA into the body, without the use of viral delivery vehicles, may cause expression of the proteins encoded by the genetic sequences. Vical has additional issued patents covering enhancements, manufacturing, and specific applications of its core technology.

About CMV

CMV is a herpes virus that infects more than half of all adults in the United States by age 40, and is even more widespread in developing countries. While a healthy immune system typically protects an infected person against CMV disease, it rarely succeeds in eliminating the infection, and those whose immune systems are not fully functional are at high risk of CMV reactivation, potentially leading to severe illness or death. Those at greatest risk include transplant patients and infants born to mothers who first become infected during pregnancy. Vical is pursuing two different vaccine approaches for these distinct market segments.

CMV affects 30% to 60% of patients undergoing transplant procedures, causing transplant rejection, serious illness and even death if untreated. Expensive and toxic antiviral drug therapy is used to control the disease, but does not eliminate the infection. There is no approved vaccine against CMV. Protein-based vaccines that predominantly result in antibody responses to CMV may have limited effectiveness in transplant patients. Live, attenuated vaccines can induce both antibody and cellular immune responses, but pose a potential safety concern, particularly for immunocompromised patients, of causing the disease they are intended to prevent.

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.

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This press release contains forward-looking statements subject to risks and uncertainties that could cause actual results to differ materially from those projected. Forward-looking statements include statements about the scope of coverage of and potential applications for Vical's patents, the potential uses and benefits of Vical's technologies and their potential application in the TransVaxT therapeutic vaccine, as well as the company's focus, collaborative partners, and independent and partnered product candidates. Risks and uncertainties include whether TransVaxT will prevent reactivation of CMV or introduction of CMV through donor cells or tissues in transplant recipients; whether Vical's issued patents will be challenged and whether such challenges will have an adverse effect on the scope or validity of the patents; whether Vical will pursue enforcement of its issued patents or be successful in any such enforcement efforts; whether Vical will successfully prosecute additional patent applications and if so, whether such applications will lead to the issuance of additional patents; whether Vical will enter into any development or commercialization collaborations for its TransVaxT program; whether Vical or others will continue development of TransVaxT or any other product candidates; whether the TransVaxT Phase 3 trial design will be allowed by regulatory authorities, and if so, whether the trial will begin in the second half of 2011, if at all; whether Vical or its collaborative partners will seek or gain approval to market TransVaxT or any other 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.

CONTACT: Alan R. Engbring 
         (858) 646-1127
         Website: www.vical.com