Vical Announces Scientific Advances for Multiple Programs at DNA Vaccines 2011 Conference

SAN DIEGO, July 14, 2011 (GLOBE NEWSWIRE) -- Vical Incorporated (Nasdaq:VICL) announced today a summary of the company's scientific presentations at the DNA Vaccines 2011 conference, (San Diego - July 12-14).

TransVaxTM

A presentation by Alain P. Rolland, Pharm.D., Ph.D., Vical's Executive Vice President of Product Development, "Phase 2 Clinical Trial Results of a Therapeutic DNA Vaccine, TransVaxTM, for Control of Cytomegalovirus in Hematopoietic Cell Transplant Recipients," features the most advanced clinical data presented at the conference. Key efficacy, immunogenicity and safety results from the completed Phase 2 trial establish Vical's TransVaxTM cytomegalovirus (CMV) vaccine as the first to provide evidence of protection in immunocompromised hematopoietic cell transplant (HCT) recipients. Through 12 months post-transplant, statistically significant improvements were achieved compared to the placebo group for all key viral reactivation endpoints: the occurrence of CMV viremia, the median time to initial viremia, the number of CMV viremia episodes, the duration of viremia, and the prevalence of CMV viremia episodes over the trial period. The presentation further outlines preparations for the planned Phase 3 registration trial of TransVaxTM.

Dr. Rolland is also a Panelist in a Plenary Roundtable, "Development and Commercialization of Novel Vaccines," and Chair of the Immune Mechanisms & Vaccine Session.

Herpes Simplex Vaccine

A presentation by Sean M. Sullivan, Ph.D., Vical's Executive Director of Pharmaceutical Sciences, "Development of Vaxfectin®-formulated HSV-2 Plasmid DNA Vaccines for Prophylactic and Therapeutic Applications," highlights the latest preclinical data from the company's herpes simplex virus type 2 (HSV-2) vaccine development program. The company previously reported encouraging data showing that its Vaxfectin®-formulated monovalent prophylactic vaccine (encoding HSV-2 glycoprotein D, or gD) protected mice against challenge with 50 times a lethal dose (LD50) of HSV-2, provided sterilizing immunity and inhibited viral counts at both primary and latent infection sites. The Vaxfectin® adjuvant significantly improved vaccine effectiveness. A Vaxfectin®-formulated trivalent therapeutic version of the vaccine (encoding gD plus the HSV-2 tegument proteins UL46 and UL47) significantly reduced (p<0.05) the recurrence of lesions in guinea pigs with latent infection as well as viral shedding. The company subsequently completed repeat studies confirming these results, which are among the best ever seen with a herpes vaccine in such a therapeutic model. New data presented at the conference shows that a 0.1 µg dose of the prophylactic vaccine provided 100% protection of mice against challenge with 50 times a lethal dose (LD50), and a 100 µg dose of the prophylactic vaccine provided 100% protection of mice against challenge with 500 times a lethal dose (LD50). The 100 µg dose of the prophylactic vaccine also significantly reduced viral shedding at the primary infection site (p<0.001) and inhibited viral counts at the latent infection site (p≤0.05). Both the monovalent and trivalent vaccines completely eliminated primary disease and recurrent disease in a prophylactic guinea pig model.

Dr. Sullivan is also presenting key data from the HSV-2 program in a poster at the conference.

CyMVectinTM

A poster presented by Jukka A. Hartikka, Ph.D., Vical's Associate Director of Vaccinology, "Preclinical Evaluation of the Immunogenicity of Plasmid DNA-based Prophylactic Vaccines for Human Cytomegalovirus," detailed the preclinical results supporting clinical development of the company's CyMVectinTM prophylactic CMV vaccine. By prophylactic vaccination of women of childbearing age CyMVectinTM is designed to prevent CMV infection and consequently maternal-fetal transmission of CMV, a leading cause of birth defects. Results from a mouse study demonstrated that immunization with a Vaxfectin®-formulated bivalent CMV vaccine, expressing gB and pp65, resulted in durable cellular immune responses. Optimizing the dosing regimen greatly increased the number of CMV-specific T cells. Data obtained in mice and rabbits demonstrated that DNA vaccines formulated with the company's Vaxfectin® adjuvant provided superior immunogenicity compared to other formulations. The Vaxfectin®-formulated DNA vaccines administered without electroporation provided equivalent or better immunogenicity than unformulated DNA vaccines followed by electroporation with either constant-voltage or constant-current devices. Needle-free delivery did not provide a significant advantage over conventional needle and syringe delivery. Accordingly, the company has formulated its CyMVectinTM vaccine with Vaxfectin® and designed its Phase 1 trial protocol with conventional needle and syringe delivery. The U.S. Food and Drug Administration has allowed the company's Investigational New Drug application (IND), clearing the path for the company to advance to initial human clinical testing of CyMVectinTM.

RapidResponseTM Platform

A poster presented by John Doukas, Ph.D., Vical's Senior Director of Preclinical Safety and Efficacy, "Advances in the Development of Linear Expression Cassette-based Pandemic Influenza A Vaccines," provides results from the company's RapidResponseTM DNA vaccine cell-free manufacturing process. The RapidResponseTM platform is designed to allow extremely rapid and large-scale production of DNA vaccines with low capital requirements. It is ideally suited to enable an immediate response against emerging diseases affecting large populations. Development of the RapidResponseTM platform was funded by a grant from the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH).

In a lethal challenge study with a pandemic influenza virus, ferrets were vaccinated with Vaxfectin®-adjuvanted, RapidResponseTM-produced vaccine. A dose of 330 μg provided complete protection against viral challenge, while a 10-fold lower dose still provided a high level of protection (83% survival rate compared to 0% in controls). Both doses reduced peak nasal wash viral titers by >40%, and stabilized body weights and temperatures. GLP-compliant repeat-dose toxicology, biodistribution, and genomic integration studies required to position such vaccines for clinical trials were conducted in rabbits and confirmed that a vaccine produced by the RapidResponseTM system was well-tolerated.

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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