Centre for Biotechnology (CBT), the institute that developed indigenous anthrax vaccine candidate is working on further improving the candidate into a drug that can cure even anthrax-affected cases in future. While the present recombinant vaccine under development can only be administered as a preventive measure, CBT expects to find a curative solution also to the threat of using anthrax as a biological weapon.

Informing this during a session on "Applications of biotechnology in pharmaceuticals, agriculture and food processing" organized as part of India Chem 2002 here, Dr Rakesh Bhatnagar, chairman, CBT said that the research has entered an advanced stage. Dr Bhatnagar explained the seven years effort that culminated in the development of anthrax vaccine candidate for the first time in the world. The vaccine is undergoing its pre-clinical trials and is expected to enter clinical trials by December end.

CBT has already given the marketing and manufacturing rights of the vaccine candidate to Delhi based Panacea Biotech. The company is in the process of obtaining the necessary clearance from the office of the Drugs Control General of India (DCGI). Dr Bhatnagar pointed out that many companies from the US, UK and France are also in the race to develop the recombinant version of the vaccine that is non-toxic as against the existing form of vaccine. He said that if India could come out with its vaccine first it would be of global demand.

Interestingly, Dr Bhatnagar, who led the team of researchers in developing the vaccine also made sure to transfer a highly cost effective fermentation technology for the vaccine. According to Dr Bhatnagar, a fermentator of five-litre capacity can produce five gram of antigen. This theoretically is a major achievement as the company can produce even one billion doses of vaccine a day if need be.

The vaccine, developed through genetically engineering of Escherichia coli (E. coli) bacteria can produce harmless, mutant forms of the three key proteins (the lethal factor, the edema factor and the protective antigen) found in anthrax bacterium, Bacillus anthracis. The technology has been optimized so that 30 per cent of the protein that is expressed from the recombined E. coli genome is the protective antigen of anthrax, whereas its expression is negligible in the existing vaccines.

The purification of the antigen is done better as compared to existing vaccines using aluminium hydroxide precipitation reaction.

Considering the potential of anthrax bacterium as biological weapon, Dr Bhatnagar''''s invention, if taken to the commercial arena, would hold great export potential as a mass immunization agent.

Dr. Bhatnagar with his team at CBT had developed the vaccine with a grant of about Rs one crore from department of biotechnology. The research project began in 1995. Although anthrax vaccines are available internationally for the last many decades, serious side effects have been associated with them. The Indian product has the advantage of maximum concentration of protective antigen and the resultant minimal toxicity.