It happens all the time: a pharmaceutical or biotechnology company will spend ten years and hundreds of millions of dollars on a drug candidate that looks spectacular in animal models of a disease, only to see it fail during clinical trials, either because of unexpected adverse reactions in a small number of patients or a surprising lack of efficacy. For every drug that is approved, on average more than 6,000 new chemical substances are created. Only seven of these ever end up being tested in humans, and only three make it to Phase III clinical trials, the final step before. | Comment Pharmacogenomics arrives Gregory A Petsko Address Rosenstiel Basic Medical Sciences Research Center Brandeis University Waltham MA 02454-9110 USA. E-mail petsko@ Published 28 May 2004 Genome Biology 2004 5 108 The electronic version of this article is the complete one and can be found online at http 2004 5 6 l08 2004 BioMed Central Ltd It happens all the time a pharmaceutical or biotechnology company will spend ten years and hundreds of millions of dollars on a drug candidate that looks spectacular in animal models of a disease only to see it fail during clinical trials either because of unexpected adverse reactions in a small number of patients or a surprising lack of efficacy. For every drug that is approved on average more than 6 000 new chemical substances are created. Only seven of these ever end up being tested in humans and only three make it to Phase III clinical trials the final step before a drug is approved by the Food and Drug Administration in the US. It takes over a decade and at least several hundred millions of dollars - sometimes close to 1 billion - to get that far and even then on average only one of three candidates will emerge from Phase III and become a marketed drug. This combination of colossal failure rate with astronomical cost - unique to the pharmaceutical industry - is the main reason new medicines are both expensive and hard to come by. Despite advances in synthetic chemistry high-throughput screening and structure-based drug discovery the number of new drugs approved has remained relatively constant at about 20-30 per year for a quarter of a century. As human lifespan increases the demand for medicines to treat more difficult diseases such as cancer heart disease autoimmune disorders and neurodegeneration is likely to cause this meager success rate to decline - which may already be happening since many big drug firms currently have rather dry pipelines. Such a trend could spell disaster for some .
