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BioSante Pharmaceuticals Announces Positive Study Results for Potential Adjuvanted Bird Flu Vaccine

Genetic Engineering News
BIOWIRE

BioSante Pharmaceuticals, Inc. (AMEX:BPA) today announced positive results of a new study demonstrating that its calcium phosphate (CaP) nanoparticle-based vaccine adjuvant, BioVant(TM), may serve as a vaccine adjuvant for the development of an effective vaccine against H5N1 avian flu, widely known as bird flu.


"As the potential danger of a pandemic rises, the need for a safe and effective bird flu vaccine grows increasingly urgent," said Stephen M. Simes, president and chief executive officer of BioSante. "A vaccine with an adjuvant included may allow for better efficacy and lower doses per vaccination which may help to prevent shortages. More importantly, addition of an adjuvant may enable more people to produce an immune response to protect them from disease."

Addition of a vaccine adjuvant has increased in importance due to a paper published in a recent issue of the New England Journal of Medicine. It was reported that an experimental bird-flu vaccine under development by the U.S. government and a European drug company without an adjuvant is effective only at high doses and that only 54 percent of subjects produced the desired immune response.

BioSante's preclinical study's objective was to determine whether BioVant could enhance the body's natural immune response to the H5N1 viral antigen, the cause of bird flu. At the start of the 10-week trial, mice received either the H5N1 antigen alone or in a formulation with BioVant. A booster immunization was administered after two weeks. Results indicated that the administration of a BioVant/H5N1 formulation stimulated production of high titers of H5N1-specific antibodies, and significantly higher than H5N1 alone. Anti-avian flu antibody levels continued to increase over the entire study period, suggesting good duration of immunity.

"These new H5N1 plus BioVant adjuvant study results may represent an important advance toward protecting the human population against a potentially deadly virus," said Dr. Steve Bell, vice president of research and preclinical development at BioSante. He noted that the demonstrated effectiveness of BioVant may also permit a reduction in the needed dosage of H5N1 antigen, which is currently in limited supply. Dr. Bell will present BioSante's avian flu data on May 8, 2006 at the Ninth Annual Conference on Vaccine Research in Baltimore, Maryland.

Avian flu refers to a large group of different influenza viruses that primarily affect birds. While the vast majority of these viruses do not affect humans, the H5N1 strain has already made the jump from birds to humans and in fact, has infected 186 people and killed 108 over the past two to three years. There is widespread concern that a strain of avian flu will mutate into a new form that is contagious among humans. Since there is currently no vaccine available to protect humans from H5N1 and humans do not have antibodies to fight this new virus strain, there is significant risk of a pandemic.

An adjuvant is a substance that, when added to a vaccine, enhances the vaccine's effectiveness by stimulating an immune system response. While aluminum salt derivatives such as alum are the only adjuvants currently approved by the FDA, alum has been associated with adverse reactions such as irritation and inflammation at the injection site, and may exacerbate allergy.

In contrast, BioVant is composed of specially formulated calcium phosphate (CaP), a compound similar to that found in teeth and bones. In multiple studies, BioVant has been shown to be safe and cause minimal dose-dependent inflammation at the injection site, and has been shown to both prevent the manifestation of allergy, and, to effectively 'switch off' established Th2-T-cell-associated allergic disease.

"We believe CaP, in the form of BioVant, shows potential to be an important non-injection delivery system and adjuvant for the next generation of vaccines against both viral and bacterial infections," Simes said. "In addition to the avian flu vaccine, BioSante and several commercial and military partners are now conducting additional pre-clinical studies of BioVant in several potential vaccines, and the company is pursuing additional collaborations and licenses for further development of CaP."

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