News roundup

Report calls for better evaluation of pharmcogenetic tests

Ray Moynihan Washington, DC

The marketing of pharmacogenetic tests may be moving much faster than the underlying medical science, warns a study published this week.

"There is widespread recognition that pharmacogenetics may have been oversold . . . The basic science is still substantially uncertain," argues its author, David Melzer, and colleagues from the Department of Public Health and Primary Care at the University of Cambridge. Funded by the Wellcome Trust, the study was based on interviews and focus groups involving key experts on pharmacogenetics and major stakeholders in the United States and the United Kingdom.

The authors found a widespread view that genetic tests have great potential to improve the safety and effectiveness of an individual patient’s drug treatment, by guiding the choices of the most appropriate drug at the best dose and by identifying whether they are at high risk of serious adverse reactions to the drugs.

The report gives the pharmacogenetics associated with warfarin as an example of a potentially useful application of the new technology, given the wide variation in dose that is required to attain a response in different patients and the risk of subsequent bleeding. Early evidence has shown that certain genetic variations are associated with an impaired ability to eliminate the drug, raising the possibility that genetic testing might help to identify more appropriate doses for patients and reduce the occurrence of serious complications.

"Although further studies are needed to replicate and confirm these findings, this application of pharmacogenetics appears to be promising and potentially near to the clinic," the report says.

The report concludes, however, that regulatory agencies should require mandatory clinical evaluation of these genetic tests for the promise of safer and more effective use of drugs to be realised. Criticising what they called "geno-hype," the authors argue that "media excitement about genetic applications may be exaggerating investment and research activity" in pharmacogenetics.

Because of this overselling, some companies may have inappropriately large investments in the field, so "commercial interests may be under pressure to market test-drug combinations as quickly as possible, to the detriment of good clinical evaluation of products."

The new report follows the launch last month by the Swiss drugs company Roche of a new diagnostic test designed to identify common genetic variations that effect people’s ability to metabolise widely used classes of drugs. The launch of the product, AmpliChip CYP450, received enthusiastic media coverage and led to excited estimates of a burgeoning market for pharmacogenetic products. A Roche press release predicted an annual market of $100m (£60m; €87m) by 2008 for this one test alone.

My Very Own Medicine: What Must I Know? is available at www.phpc.cam.ac.uk/epg/IPP.html

© 2003 BMJ Publishing Group Ltd