The trials and tribulations of amylin
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found widely disseminated throughout the body, with the highest levels in the liver, spleen, lymph nodes, and bone marrow. Interestingly, the bone marrow was found to be severely depleted of red blood cell precursors ± a condition which probably pre-dated the gene therapy. Currently some sort of overwhelming immune reaction to the treatment seems to be the favoured explanation. The incident conveys some important lessons; modi®ed adenoviruses are a favoured vector for gene therapy, but the risks of administering live viruses have been raised on several occasions ± particularly in the case of lung disorders, since there have been suggestions that adenoviruses can chronically colonise airway epithelia and exacerbate chronic lung disease. The viral vector can also cause signi®cant host cell cytotoxicity, and generate immune responses which limit the ability to repeat the treatment [3]. Non-living vectors (for example, liposomes) or viruses which have been rendered incapable of replication may be a safer option [4]. Approved study protocols are there to be followed; violations are potentially dangerous and unethical, and an unexpected tragedy such as this may expose the conduct of
the study to public scrutiny, and any deviations might lay the investigators open to legal action. Lastly, occurrences like this cast a cloud over a novel form of therapy which offers potential relief to hitherto incurable patients. The latest news is that the FDA have put all 8 gene therapy trials currently running at the University of Pennsylvania on clinical hold [5].
References 16. Marshall E. Gene therapy prompts review of adenovirus vector. Science 1999; 286:2244±2245. 17. Hollon T. Researchers and regulators reflect on first gene therapy death. Nature Medicine 2000; 6:6. 18. Ennist D. Gene therapy for lung disease. Trends Pharmacol Sci 1999; 20:260±266. 19. Wang Y and Huang S. Adenovirus technology for gene manipulation and functional studies. Drug Discovery Today 2000; 5:10±16. 20. Anon. Gene therapy under cloud. Lancet 2000; 355:329.
The trials and tribulations of amylin Collaborative work on new medicines by discoverers and developers, who belong to totally different organisations, can produce disappointments. The discovery organisation, which may be an academic unit or a start-up company, often formed by academic researchers supported by venture-capital investors, may have a different ethos and aim to the developers. The objective may be simply to capitalise on the discovery and then shut down, certainly as far as the investors are concerned. The academic discoverers may retain a conviction that it has `true potential' or is even a `breakthrough'. The developers are usually `big pharma', looking to enter a new therapeutic area or to develop a drug with a unique action and/or potential. Their stepwise assessment of its properties will certainly be as critical as their decision-making processes concerning their own inhouse discoveries, possibly more so. Early proof of concept encapsulates their approach. With that ba
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