Vical’s DNA Vaccine Provides Complete Protection Against Avian Influenza and Demonstrates Cross-protection Against Multiple Human Flu Strains in Animal Studies
Vical Incorporated (Nasdaq: VICL – News) announced today that the company’s lead three-component influenza (flu) DNA vaccine candidate provided 100% protection in mice and ferrets against lethal challenges with a highly virulent (Vietnam/1203/2004) H5N1 avian influenza virus in studies conducted by Richard J. Webby, Ph.D., at St. Jude Children’s Research Hospital. Additionally, in these and earlier studies in mice, simplified versions of Vical’s vaccine candidate using only two of the three components provided high levels of protection against multiple human flu strains and against the H5N1 avian flu strain, which is important because a pandemic could arise from a strain other than H5N1. The studies were part of the company’s program to develop a DNA vaccine that protects humans against emerging strains of flu virus that have the potential to cause a pandemic. Based on the results, the company is continuing to advance toward human testing of the pandemic flu DNA vaccine candidate.
“We are encouraged by the protection afforded by our avian flu vaccine and by the cross-protection data,” said Vijay B. Samant, President and Chief Executive Officer of Vical. “Achieving cross-protection is the ultimate goal in flu vaccines, and the current studies provide evidence that such a goal may be feasible using a DNA vaccine targeting conserved influenza virus proteins and formulated with our proprietary Vaxfectin(TM) adjuvant. It is also important to note that DNA vaccines do not rely on chicken eggs or complex cell culture manufacturing methods. DNA vaccines are manufactured by simple bacterial fermentation methods that may allow production of large quantities in a short period of time.”
Protection Against Sickness and Death
In the studies, mice and ferrets vaccinated with Vical’s lead DNA vaccine candidate and those which received a blank DNA control were challenged with the H5N1 avian flu virus. All vaccinated animals survived while those which received the control did not survive. In addition to providing complete protection against the virus, the company’s lead DNA vaccine candidate also prevented weight loss in all animals, suggesting that it is able to provide protection against serious flu-related sickness as well as death.
The company’s three-component pandemic flu DNA vaccine candidate targets one “variable” and two “conserved” influenza virus proteins. In testing of the company’s simplified two-component DNA vaccine candidates against avian flu, which target only the two conserved influenza virus proteins, 14 of 16 mice in each of two vaccine groups survived with moderate weight loss. The study is the first to provide evidence that a vaccine targeting conserved influenza virus proteins without matched surface proteins can provide protection against such a highly virulent H5N1 flu strain. In previous studies, the company also showed that the same vaccine formulation provided up to 100% protection against two strains of human influenza.
“A vaccine that provides cross-protection against more than one strain of flu is important for addressing a pandemic flu threat because it is likely that the H5N1 virus could mutate before it becomes transmissible from human to human,” said Dr. Webby. “The current data show that this vaccine has the potential to achieve cross-protection because it targets two conserved flu virus proteins as well as H5.”
The avian flu challenge studies included 16 mice or 6 ferrets in each vaccine or control group. The DNA vaccines tested in mice and ferrets targeted two highly-conserved influenza virus proteins — nucleoprotein (NP) and matrix protein (M2) — with and without the H5 avian influenza virus surface protein. This approach may provide broad-based protection against an emerging pandemic flu strain prior to the identification and development of a matched HA vaccine component. All tested DNA vaccines were formulated with the company’s patented Vaxfectin(TM) adjuvant, which had demonstrated statistically superior protection in mice compared with other formulations in prior studies. Data from these studies are scheduled to be included in a presentation by Dr. Webby on avian and pandemic flu at the U.S. Public Health Service Professional Conference in Denver, Colo., on May 3. Funding for the studies was included under a previously-announced grant from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health.
Details of the study design and data will be reviewed in the company’s quarterly financial results conference call with invited analysts and institutional investors at noon Eastern Time today, Tuesday, May 2. The call and webcast are open on a listen-only basis to any interested parties. To listen to the conference call, dial (888) 224-3260, or (913) 905-1086 for international participants. A replay of the call will be available for 48 hours beginning about two hours after the call. To listen to the replay, dial (888) 203-1112, or (719) 457-0820 for international participants, and enter conference identification number 2477734. The call also will be available live and archived through the webcast center at www.vical.com.
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 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 Vical or others will continue development of the pandemic influenza vaccine; whether H5N1 or other strains of avian influenza will emerge as pandemic threats; whether the vaccine will be effective in protecting humans against H5N1 or other strains of avian influenza; whether the vaccine will provide protection against serious flu- related sickness; whether the vaccine will be able to provide cross-protection against emerging strains of influenza; the timing, nature and cost of any additional development; whether any other product candidates under development by Vical or its collaborators will be shown to be safe and effective; whether Vical or its collaborative partners will seek or gain approval to market 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.
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Vical Incorporated Porter Novelli Life Sciences
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