SAN DIEGO, Sept. 14 /PRNewswire-FirstCall/ -- Vical Incorporated announced today that peer-reviewed data from the company’s anthrax vaccine challenge study in rabbits were published in the September 14 issue of the Proceedings of the National Academy of Sciences (PNAS). The novel DNA-based vaccine being developed by Vical generated antibodies against specific anthrax proteins and provided complete protection of rabbits against aerosolized inhalation spore challenge more than seven months after vaccination. Rabbits will likely be accepted by the U.S. Food and Drug Administration (FDA) as an animal model for anthrax under the Animal Rule, which allows marketing approval based on proof of protective efficacy in two animal models and both safety and immunogenicity in humans.
Vical’s investigational DNA vaccine for anthrax, formulated with cationic lipids, encodes detoxified forms of both the Protective Antigen (PA) and Lethal Factor (LF) anthrax proteins, which in their natural forms combine to form lethal toxin (Letx). This bivalent vaccine is designed to provide broader protection than other anthrax vaccines which target PA alone, including the vaccine currently licensed in the United States and others under development. Significant levels of anti-PA, anti-LF and Letx-neutralizing antibodies were achieved in the rabbit study. In addition, post-challenge immune response data from the rabbit study suggest that the vaccine-generated antibodies may inhibit germination of anthrax spores, potentially providing sterile immunity.
David C. Kaslow, M.D., Vical’s Chief Scientific Officer, said, “The successful testing of our anthrax vaccine in rabbits is an important milestone in our ongoing progress toward developing a safe and effective vaccine against weaponized forms of anthrax. With appropriate guidance from the FDA on the new Animal Rule, an application for marketing approval could be based on effectiveness testing in accepted animal challenge models such as the rabbit, coupled with clinical safety and immunogenicity trials in humans, without the need for conventional clinical efficacy trials.”
The PNAS article, “A cationic lipid-formulated plasmid DNA vaccine confers sustained antibody-mediated protection against aerosolized anthrax spores,” is available without charge online at http://www.pnas.org/cgi/doi/10.1073/pnas.0405557101. The preclinical study involved researchers from Vical, The Ohio State University, and the Naval Medical Research Center.
“Based on the successful demonstration in rabbits that our state-of-the-art DNA vaccine has been optimized for eliciting antibodies, we have now initiated proof-of-concept testing in man,” added Dr. Kaslow. “Success with this vaccine would help meet the unmet need for safe, effective and practical biodefense vaccines and could open the door to a broad range of other antibody-mediated vaccine applications.”
The rabbit study was supported by a Small Business Technology Transfer Research (STTR) grant from the U.S. National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH). The company also received a three-year, $5.9 million Phase II Small Business Innovation Research (SBIR) grant from the NIAID for additional non-clinical development. The vaccine is now being tested for safety and immune responses in a Phase 1 clinical trial in healthy human volunteers at two NIAID-funded Vaccine and Treatment Evaluation Units (VTEUs). The company intends to seek additional government funding to support further development.
About Anthrax
Anthrax is a serious infectious disease most frequently occurring in hoofed mammals, but also affecting humans exposed to the spore-forming Bacillus anthracis. Bacterial spores can survive for extended periods and become active upon gaining access to a host. Human infection with anthrax spores can occur after exposure through a cut or abrasion on the skin or through ingestion of contaminated meat, but the most serious risk is through inhalation.
Inhalation anthrax results in death for 90 percent to 100 percent of those exposed, if not treated promptly. Symptoms typically appear within a week of exposure, and may be misdiagnosed as a common cold or flu. Bacterial spores travel from the lungs to the lymph nodes, where they begin to grow. Eventually, they spread into the circulatory system and throughout the body, causing widespread internal bleeding and organ failure. People who work with animals or process animal products are at greatest risk of naturally acquired infection. The greatest potential threat for most people is the inhalation of anthrax spores used in biological warfare or in a bioterrorist attack.
The toxic effects of anthrax infection are the result of three proteins produced by the bacteria: edema factor (EF), lethal factor and protective antigen. PA couples with either EF or LF and allows these toxins to penetrate and kill host cells, releasing large numbers of bacteria into circulation. Treatment for proven or suspected anthrax infection involves a long course of antibiotic therapy beginning as soon as possible after diagnosis or suspected exposure. Antibiotics used against anthrax work by killing the bacteria to prevent further production of the toxic proteins. They do not eliminate proteins that accumulate before treatment, and do not offer residual protection against infection after the treatment course has been completed.
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 has retained all rights to its internally developed product candidates. 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 serve 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. Forward-looking statements include statements about the use of Vical’s DNA delivery technology in the development of vaccines for anthrax and other infectious diseases, and the potential for Vical’s DNA vaccine technology to be applied to anthrax and other infectious diseases, as well as the company’s focus, collaborative partners, product candidates, and developmental status. Risks and uncertainties include whether human trials of the company’s anthrax vaccine will confirm the immune responses observed in animal studies, whether vaccines for anthrax or other infectious diseases will be developed and approved, whether the FDA will accept rabbits as one of the animal models for anthrax under the Animal Rule, whether the FDA will accept an application for marketing approval for the company’s anthrax vaccine based on accepted animal challenge models, whether use of Vical’s technology in such vaccines will provide protective immune responses to such diseases and will result in products that are better than competing products, whether any product candidates will be shown to be safe and efficacious in clinical trials, the timing of clinical trials, whether additional government funding will be available for the company’s anthrax vaccine, whether use of the company’s technology will extend to new product opportunities for humans and animals, whether Vical or its collaborative partners will seek or gain approval to market any product candidates, the dependence of the company on its collaborative partners, 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.
For further information, please contact: investors, Alan R. Engbring of Vical Incorporated, +1-858-646-1127; or media, Susan Neath of Atkins + Associates, +1-858-527-3486, for Vical Incorporated.
Vical Incorporated
CONTACT: investors, Alan R. Engbring of Vical Incorporated,+1-858-646-1127; or media, Susan Neath of Atkins + Associates,+1-858-527-3486, for Vical Incorporated
Web site: http://www.pnas.org/cgi/doi/10.1073/pnas.0405557101
Web site: http://www.vical.com/