Desktop-device uses advanced DNA chip to analyse patient's blood.
Japanese companies say they have built a desktop machine that will allow doctors to assess patients' DNA from a single drop of blood, and so tailor treatment to an individual's genes. The machine can deliver results within an hour, they say, and will be on sale for 5 million yen (US$44,000) by autumn 2006.
Safe dosage, effectiveness and side effects for any given drug vary from patient to patient. And determining which drug and dosage is best for any given individual is a critical challenge facing healthcare specialists.
But the announcement about the Japanese machine on 27 September came just a week after scientists in the United Kingdom spoke out against the hype surrounding personalized medicine. A report produced by the Royal Society warned that prescriptions tailored to a patient's genes are at least 15 to 20 years away.
The Japanese device was developed by the genomics facility of the Institute of Chemical and Physical Research (RIKEN) in Yokohama, the printing company Toppan in Tokyo, and the Kyoto-based maker of scientific equipment Shimadzu. Shimadzu's Takaaki Sato, who led Shimadzu's development efforts, says the key advance is a chip that analyses DNA in a blood sample, thereby bypassing the time-consuming DNA purification steps currently needed.
Although Sato will not give further details, he says that any health worker could use the machine to test a drop of blood for a particular genotype, and get a result in an hour. “Patients do not want to wait a week or even a day for results before being able to take a medicine, especially if they have an infectious disease,” says Sato.
According to RIKEN and Shimadzu, the machine will first be tested on patients being prescribed one of two medicines: an antibody called irinotecan, which can cause hearing loss in people with a certain mutation in their mitochondrial DNA, and the anticoagulant warfarin, which causes excessive bleeding in some patients.
But there is scepticism over how useful the device will be. David Weatherall of the Weatherall Institute of Molecular Medicine at the University of Oxford, UK, who worked on the Royal Society report, says the metabolism of warfarin is related to at least two genes whose interaction is not understood. Other factors, such as the patient's age or additional drugs being taken, also need to be considered, he says.
“There is no way around these problems except to test each drug independently in large population studies, and to monitor all these issues over several years,” he says. “There is still a huge gap between the scientists who do this kind of work and its application for practical purposes.”
Sato admits that initially his machine will be most useful for research. But judging from the “unbelievable number of responses” received since announcing the test, he says there is no way that 15 years will pass before doctors are using such devices for day-to-day diagnosis and treatment.
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