If a pharmaceuticals giant casts doubt on whether medicines work, is it worth taking them at all? Sophie Petit-Zeman reports.
When a giant of the drug industry claims most medicines don't work for most people who take them, is it time to ditch our prescriptions and take up prayer? Dr Allen Roses, the worldwide vice-president of genetics at GlaxoSmithKline, was recently quoted as saying that the vast majority of drugs - more than 90 per cent - work in only 30 to 50 per cent of cases.
Such an admission may seem alarming. But is it so surprising? Not according to Richard Ley of the Association of the British Pharmaceutical Industry, a trade association for companies producing prescription medicines. "It's not really news to anyone that not all medicines work in all the people all of the time. What is certainly true is that we often don't know why." And he agrees with Roses that the answer is likely to lie in people's genetic make-up.
But for patients who depend heavily on their prescriptions, the admission will come as more of a shock. So why is the efficacy rate of some drugs so poor, and why does one drug work for one patient and not for another?
As scientists unravel the secrets of the genetic code, they are finding out more about the importance of variations between the proteins for which genes code in determining how individuals respond to drugs.
Pharmacogenetics and pharmacogenomics are focusing on, respectively, the roles of single genes and the whole collection, or genome. Work in these areas aims to enable better targeting of drugs to people who would most benefit, and indeed suffer fewer side effects, and allow drug companies to refine products.
David Goldstein, professor of genetics at University College London, points out: "We actually know of about 42 genetic differences which affect how we respond to drug treatments, and this body of knowledge is growing. What is less clear is how to get such knowledge translated into real improvements in drugs and, hence, improve treatments."
Ley stresses that alongside genetic bases of drug responses, the lack of knowledge about the fundamental processes underlying many conditions explains in part why it can be so difficult to find effective treatments. "Take asthma, for example. We're not yet sure what causes it, and it's probably a complex mix of genetic and environmental factors. Knowing more about these basics will help researchers to find new and better drug treatments."
He also points out: "It's important not to get too worried when we hear that a drug helps, for example, 30 per cent of those who take it. As long as you have three drugs for that condition, you may well find something for almost everyone who needs it.
"This is why it is important to go on researching and developing more medication, even though this is sometimes criticised as making useless variations on a theme. It's the only way to extend coverage so that we have effective treatments for all who need them."
It seems pharmacogenetics has promise but does not hold all the answers. Dr Mike Clarke, director of the UK Cochrane Centre, part of a renowned international collaboration that helps people to make better decisions about their healthcare (www.cochrane.org), is adamant that better and bigger drug trials are an immediate way forward.
"People are more complex than their genes, though they're complex enough. We need to do bigger trials, which enable us to look at patient subgroups, and to look at the quality of the evidence emerging from these trials in a systematic way," he says."With all this pharmacogenetic research around, we'll also have to ensure that the research itself is systematically reviewed to, basically, be sure that it's good."