Swedes say genetics can help drug selection
Do benefits outweigh privacy implications?
Members of a Swedish research team say physicians one day may use genetic tests to determine how well a drug will treat a patient's condition long before they write the first prescription. Doctors say there is a great need to be able to preview how a patient will respond to a drug. The benefits that could come from such tests far outweigh the risks to society, such as genetically stigmatizing some patients as difficult to treat, they say.
At the recent Ninth European Meeting on Hypertension in Italy, the researchers from Uppsala University and Eurona Medical AB announced they could identify a genetic marker in 31 of 102 patients, which they said would indicate a good response to ACE inhibitors.
Results of the study
Seventy-three percent of these patients had successful drug therapy, defined as a reduction of diastolic blood pressure by more than 10 mmHg or reaching a level below 90 mmHg. In the remaining patients who did not have this ACE inhibitor responder signature, 42% still had positive results.
Lead researcher Hans Lithell, MD, PhD, says his team is beginning with ACE inhibitors and hopes to be able to develop similar techniques for other classes of drugs like beta-blockers, diuretics, angiotensin II inhibitors, and calcium channel blockers. "Today, doctors start treatment quite blindly," says Lithell, professor of geriatrics at Uppsala University. "Nobody knows any characteristics of which drug to start with."
In general, he says, doctors know how to match drugs and the conditions they treat. But on an individual basis, one patient may do well on a drug while another patient with the same condition may not. Lithell says his team is working out a way to recognize genetic patterns — or polymorphisms — in patients that are related to favorable responses to particular types of drugs. "Our first study is with ACE inhibition," he says. "There is that relationship there."
Whether Lithell's study is a breakthrough or another step in the direction of a test is not certain, says Jay N. Cohn, MD, professor of medicine at the University of Minnesota in Minneapolis. He says physicians must be able to apply the findings of large clinical trials to their individual patients in their own practices.
When large clinical drug trials become available, they show the trends of how patients responded to the treatment. "But everyone within the trial doesn't benefit," Cohn says. Doctors just can't get a copy of the published study and be able to tease out how individuals did. "I don't think we should slow down the search for genetic markers for response because they will have social implications. Social issues have to be addressed as they develop."
Says William Fassett, PhD, MBA, a pharmacy ethicist and dean of the school of pharmacy at the University of Washington in Seattle, "The need to be able to test drugs is so great that people will want that. You're not going to stop the science." The question to address is not how to control the science, he explains, but how to use the information scientific research provides.
"It's just what we are dealing with now," says Bill Allen, JD, assistant professor for the Program of Medical Ethics, Law and Humanities at the University of Florida College of Medicine in Gainesville. He notes things can get a bit tangled when determining how the law protects patients' privacy of genetic information. In Florida, for example, genetic information is considered private unless a patient gives consent for others to use it.
There is protection under federal law, says Philip Reilly, MD, JD, president and CEO of the Eunice Kennedy Shriver Center in Waltham, MA, a research facility for developmental disabilities and mental retardation, and an editor of The Gene Letter. People are protected through the Health Insurance Portability and Accountability Act of 1996, he says, which keeps insurance companies from using genetic material as a basis for rejecting people who are switching health plans.
Lithell's test doesn't set off any alarms, he says, mostly because doctors need to have such tests to tailor care. He adds that he speaks with insurers all the time. They tell him they'll avoid using information as a basis for their underwriting because the controversy "and political hot water" isn't worth the money they could save.
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