Dynavax Anthrax Vaccine Induces High Antibody Responses and Shows Protection in Preclinical Model
BERKELEY, Calif., March 21, 2005 /PRNewswire-FirstCall via COMTEX/ -- Dynavax Technologies (Nasdaq: DVAX) presented data from preclinical models suggesting that the company's immunostimulatory sequence (ISS) based anthrax vaccine has the potential to confer higher levels of immunity quickly and effectively against the threat of anthrax infection, and may represent a potent new vaccine approach for anthrax. The vaccine demonstrated a significant increase in potency when compared to the currently available anthrax vaccine and a prototype second-generation vaccine.
"Our novel, proprietary anthrax vaccine formulation has potential as a fast and effective alternative to the current vaccine -- known for its difficult administration and severely limiting side effects -- as well as to second-generation approaches that combine rPA with alum and may not have sufficient potency to confer immunity," said Dino Dina, MD, president and chief executive officer.
"These early experiments show the robustness and enhanced potency of our ISS-based approach, and provide a strong rationale for continued development of a vaccine that could provide enhanced protection from a significant bioterror threat."
The data were presented at the 2005 American Society for Microbiology's Biodefense Research Meeting in a poster entitled, "Immunostimulatory Oligonucleotide Adjuvant Formulation Increases rPA Vaccine Response and Provides Protection from Challenge in Mice" (The study was supported by a three-and-a-half year, $3.7 million grant to Dynavax from the National Institute of Allergy and Infectious Diseases). The 2003 award supports research and development of an advanced anthrax vaccine.
Dynavax's anthrax vaccine is composed of recombinant anthrax protective antigen, or rPA, combined with advanced ISS enhanced by a proprietary formulation. The data showed that rPA combined with ISS generated significantly higher antibody responses compared to rPA alone or rPA combined with the standard vaccine adjuvant, alum. The vaccine also provided protective immunity against anthrax challenge in a highly susceptible mouse strain.
Study Design and Results
Dynavax's proprietary anthrax vaccine consists of the ISS molecule formulated with the antibiotic polymyxin B (ISS/PMX). In these experiments, A/J mice, which are highly susceptible to the toxin component of anthrax infection were immunized with either rPA, rPA plus alum, the current licensed vaccine, Anthrax Vaccine Adsorbed (AVA), rPA plus ISS, or rPA plus ISS/PMX. Doses were administered at day zero, or at day zero and 14, and results were analyzed at various times after each dose. Some mice receiving two doses were also challenged with anthrax spores by intranasal instillation at day 28 and monitored for survival for two weeks.
Mice immunized with formulations containing ISS demonstrated a dramatic increase in total anti-rPA antibody titer and a significant increase in anti-rPA immunoglobulin 2a (IgG2a) compared to animals receiving AVA or rPA with alum. IgG2a is a complement fixing isotype in mice that is typically induced by ISS. The ISS/PMX formulation provided significant enhancement of the functional antibody response as measured by toxin neutralization titers compared to rPA alone (287-fold higher), rPA with alum (43-fold higher), and AVA-treated (137-fold higher) mice. rPA delivered with the ISS/PMX formulation increased neutralization responses approximately eight fold over rPA delivered with ISS alone. Additionally, immunization with rPA plus ISS/PMX provided clear protection against spore challenge.
About Dynavax
Dynavax Technologies Corporation discovers, develops, and intends to commercialize innovative products to treat and prevent allergies, infectious diseases, and chronic inflammatory diseases using versatile, proprietary approaches that alter immune system responses in highly specific ways. Our clinical development programs are based on immunostimulatory sequences, or ISS, which are short DNA sequences that enhance the ability of the immune system to fight disease and control chronic inflammation. ISS are being developed in three initial indications: a ragweed allergy immunotherapeutic, currently in a Phase 2/3 clinical trial; a hepatitis B vaccine that is currently in a Phase 2/3 clinical trial; and an asthma immunotherapeutic that has completed a Phase 2 exploratory trial.
Dynavax cautions you that statements included in this press release that are not a description of historical facts are forward-looking statements, including without limitation all statements related to the potential of its experimental anthrax vaccine and plans to advance its clinical programs and demonstrate the potential of its ISS technology. Words such as "believes," "anticipates," "plans," "expects," "intend," "will," "slated," "goal" and similar expressions are intended to identify forward-looking statements. The inclusion of forward-looking statements should not be regarded as a representation by Dynavax that any of its plans will be achieved. Actual results may differ materially from those set forth in this release due to the risks and uncertainties inherent in Dynavax's business including, without limitation, risks relating to: expectations concerning the speed, effectiveness and potency of Dynavax's proprietary anthrax vaccine, and rationale for continued development; the progress and timing of its clinical trials in ragweed allergy, hepatitis B prophylaxis and asthma; difficulties or delays in developing, testing, obtaining regulatory approval of, producing and marketing its products; the scope and validity of patent protection for its products; competition from other pharmaceutical or biotechnology companies; its ability to obtain additional financing to support its operations; its ability to maintain effective financial planning and internal controls; and other risks detailed in the "Risk Factors" section of Dynavax's Annual Report on Form 10-K filed on March 18, 2005, and in the section titled "Additional Factors That May Affect Future Results" within Dynavax's quarterly report on Form 10-Q filed on November 8, 2004. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement and Dynavax undertakes no obligation to revise or update this news release to reflect events or circumstances after the date hereof.
SOURCE Dynavax Technologies Corporation
Jane M. Green, PhD, Vice President, Corporate Communications of Dynavax Technologies
Corporation, +1-510-665-4630, or jgreen@dvax.com
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