New gene chip will 'revolutionise' drug testing and prescription

The Basel-based pharmaceutical giant Roche has launched the world's first 'gene chip' for testing how individuals react to common drugs. Experts hope the Amplichip CYP450 chip will revolutionise the way drugs are developed, tested and prescribed.

Doctors rely on a trial-and-error approach when using advanced drugs, and Roche says the gene chip will help avoid exposing patients to potentially dangerous side effects by identifying small variations in two genes affecting drug response.

The genes play a key role in determining how individuals metabolise drugs, including treatments for depression, cardiovascular disease, high blood pressure and hyperactivity. It will launch the new technology in the US first, with Europe set to follow at the end of the year. The test is part of the growing field of what is known as personalised medicine, or pharmacogenomics.

The science is based on the fact that around 10% of Caucasians and 20% of Asians metabolise drugs poorly, while a smaller proportion of people react very quickly. Both groups are at risk if given standard doses.

Poor metabolisers - those whose bodies retain medicines longer than normal - are likely to suffer adverse reactions, while ultra-fast metabolisers are in danger of not receiving enough of the drug. Roche estimates some 25m people worldwide could benefit from pre-testing before they are given drugs. Sales of the Amplichip CYP450, which will initially cost $350-400 (SFr600-660) per test, are expected to reach $100m by 2008.

Heino von Prondzynski, head of Roche's diagnostics division, believes the global gene chip market could be worth $8-10bn by 2015. A gene chip, or micro-array, is a thumbnail-sized glass plate containing fragments of DNA that can be used to screen tens of thousands of individual DNA pieces for certain genes.