Of all things that biotechnology has been used for, drug development and the pharmaceutical industry can be counted amongst the biggest beneficiaries. The reason is mainly that the end-products are so highly valued that we do not usually bother about their production process and the productivity was greatly improved. This article focuses on the how the pharmaceutical industry grew as a result of the manipulation of biological systems and makes an attempt to explain why biotechnology products are readily embraced in the medical world. Special attention will be paid to two protein drugs, insulin and the growth hormone.
The early eighties saw the first use of E. coli in for the recombinant human insulin production, leading to the approval of a genetically engineered product for therapeutic purposes for the first time. The process involved cloning and subsequent expression of the hetero-dimeric human insulin gene in E. coli, translating to biosynthesis of an almost complete human protein in a non-human biological system. Previously diabetic patients relied on bovine and swine insulin which are similar to human insulin but are not entirely the same and presented a risk of unknown zoonotic disease transfer. Use of E. coli for recombinant human insulin production also increased efficiency and volumes of production resulting is significant production cost reduction, thus making the protein available at a lower cost to the public.
The processes involved may be the reason for its wide acceptance. In the initial protocol nucleotides coding for insulin A and -B chains were introduced into different E. coli cells. Transformed cells were then cultured in large fermentation chambers prior to purification using chromatographic techniques to produce the insulin chains. The A and B insulin chains were then incubated together under optimal oxidizing conditions to facilitate formation of disulphide bond resulting in recombinant human insulin. A different which entailed insertion of the human proinsulin nucleotide into recombinant E. coli followed by an in-vitro proteolytic excision of the C peptide was developed. This method gained more popularity because it only used one fermentation chamber and the purification system was less complicated.
Human growth hormone is an important peptide drug now easily available on the market, thanks gene transfer technology. Before the production of the recombinant human growth hormone, growth hormone was derived from cadavers and there were cases were recipients on this product suffered from Creutzfeldt-Jakob disease (a human equivalent of the mad cow disease). It is quite logical that many patients were not very keen to take it for both ethical and health reasons. The hormone comprises 191 amino acid residues with two characteristic intra-chain disulphide links. Technology involved in the manufacture is almost similar to insulin. The nucleotide inserted into an E. coli vector before prior to expression in the bacteria. The product is then processed to get rid of the bacterial material. Currently production is done using mammalian cells to allow for efficient post-translational modification and thus ensuring protein stability and activity.
Efficiency in protein drugs production brought about by recombinant DNA and gene transfer technologies meant easier access of essential drugs by the general public. However, one must not forget that the greatest benefits were derived by the transnational pharmaceutical giants who funded research in these areas and ended up owning the production lines for such drugs. With approval of the first genetically engineered therapeutics, the early eighties and late seventies saw the birth of new molecular genetics companies.
The market dominance by Genentech, Amgen and Biogen on the drug development and synthesis scene can not the over emphasized. Amgen (established in 1980 and now found in 36 countries) is currently the biggest biotech company with at least 9 principal biotech products on the market and its 2009 sales amounted to $14.4 billion dollars. Genentech is equally huge with more than 13 000 employees in well over 150 countries worldwide (now that it has joined the Roche family). The popularity rose in 1981 when they were the first to release recombinant human growth hormone and to date growth hormone is one of the many biopharmaceutical produced by Genentech. The company was formed in 1976 and had its initial public offering in 1980 with a million shares going for $35.00. By the time they merged with Roche each share was going for $18.00. By the time that Roche acquired all common shares from Genentech, March 2009, each was worth $95.00. Biogen is another noteworthy company who defines its core business as human therapeutics. Presently it has three products on the market and twenty more in the pipeline awaiting approval, with its third highest earner (TYSABRI a recombinant monoclonal human antibody used to treat multiple sclerosis) netting more than a billion dollars in the last year. The success stories of these three companies are clear testimony as to how recombinant DNA technology helped the growth of the pharmaceutical industry in the past 30 years. This paints a clear picture of how scientific innovations have transformed the medical world and economies of these companies and many other sectors involved.
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Amolecular biology research student working pharmaceutical plants.
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