BioSante adjuvant looks promising
vaccine manufacturers race towards finding the most efficient bird
flu vaccine.
With the potential threat of an avian flu pandemic and the fear there would not be enough vaccine available, the need for an effective adjuvant is highly desirable, which would mean the vaccine could be spread further, vaccinating more people with a better immune response. The calcium phosphate (CaP) nanoparticle-based vaccine adjuvant, BioVant, has shown promise in the company's study using hemagglutination inhibition assay (HIA). Findings showed, after a prime and one booster of BioVant-H5N1-combination-vaccine, the immune response in a rodent model was four-fold that of the H5N1 antigen alone. "We are working to create a vaccine using out BioVant that would be given at lower doses per injection yet still confer a higher level of immunity than the currently approved vaccine," BioSante president and chief executive Stephen Simes said. "These HIA study results confirm the BioVant antibody results previously reported and add to the database for a potential BioSante improved BioVant adjuvanted bird flu vaccine." The US-based company's adjuvant worked by allowing better uptake of the antigen presenting cells (APCs), which were specific to the H5N1 antigen. Currently, Sanofi-Pasteur has the only US approved H5N1 vaccine. However, it does not contain an adjuvant. "According to a paper published in the New England Journal of Medicine, the currently approved bird-flu vaccine without an adjuvant by a European drug company is effective only at high doses - 90micograms per dose - and only 54 per cent of subjects produced the desired response," Simes said. "We believe a BioVant-adjuvanted H5N1 vaccine may use less antigen per dose and protect a higher percentage of the population." Simes told US-PharmaTechnologist.com BioVant could reduce the amount of vaccine dose to just 2micrograms per dose and still have an effective immune response. Simes said there were other advantages to BioVant, including it worked particularly well with viruses, whereas the aluminum-based adjuvant currently approved in the US was better suited for bacterial vaccines. Being a calcium-based adjuvant, Simes said it was highly biodegradable in the body and was less likely to cause an allergic reaction, unlike the aluminum adjuvant. "We believe this is safer and more effective." Other studies using viral vaccine antigens also suggest the CaP technology may sustain higher antibody levels over a longer period than both aluminum-formulated vaccines and non-adjuvanted vaccines. The Company has conducted pre-clinical studies to demonstrate the safety and efficacy of its adjuvant using various viruses and bacteria including anthrax, hepatitis B, flu (H5N1 avian and seasonal), and herpes simplex virus type-2 (HSV-2). Studies are expected to move into ferret models now. Since the outbreak of bird flu in 2003, the virus has infected 310 people and killed 190, while more than 250 million chickens have been killed to stop the spread of the virus. As there is no current vaccine against H5N1, and humans do not have antibodies to fight the new virus strain, there is a significant risk of a pandemic. The U.S. Department of Health and Human Services (HHS) recently awarded $1 billion to drug-makers, including nearly $700 million to GlaxoSmithKline, Novartis and MedImmune, to help them develop a faster method of producing an influenza vaccine to better protect the nation against the possibility of a pandemic. Yesterday, US-PharmaTechnologist.com reported the National institute of Allergy and Infectious diseases (NIAID) awarded a $3.6m grant to AlphaVax for the development of its adjuvant technology based on the company's vector platform using alphavirus RNA replicon vectors, which create a T cell immune response.
