CVS, Medco at vanguard of effort to match patients, drugs by genetic tests, January 26, 2010, by Carolyn Y. Johnson  —  For years, hype has built around personalized medicine – a tantalizing future in which insights gleaned from genetic tests will result in individualized treatment, guiding the drugs people take and at what doses.

Now, moves by two large companies that focus on controlling drug costs are leading the way for the field to become a routine part of medicine.

CVS Caremark, the Woonsocket, R.I., company that is the largest provider of prescriptions in the United States, said late last year it expects to begin offering genetic testing services to clients of its pharmacy benefit management program this year. It also invested in Generation Health, a company with offices in Waltham that is focused on helping companies manage costs and improve health by using genetic information.

A CVS competitor, Medco Health Solutions, offers genetic tests to guide the use of two drugs and plans to add four more tests this year. Medco has 270 clients, representing 7 million people, participating in its personalized medicine program.

The companies work with insurance plans or large employers and use their buying power to keep drug costs low. They want to use genetic tests to sift out patients who are unlikely to benefit from a drug they have been prescribed or who could experience dangerous or costly side effects.

When a doctor submits a prescription, for example, the company that manages a patient’s drug benefits may call the doctor and offer a genetic test. Ultimately, results might discourage the doctor from prescribing a drug that won’t work, help determined what dosage to use, or suggest an equally effective generic option. CVS said that testing would be integrated into the prescription-filling process.

“The hope is that as we learn more and more about the genome . . . we’ll be in the situation where a lot of different kinds of medications will have the choice of the medication or the dosing of the medication indicated by a genetic test,’’ said Dr. Troyen Brennan, chief medical officer of CVS.

The companies’ interest in using genetic information stems from a longstanding problem: Drugs may be more effective in some patients than others, and doctors often have no way of knowing before they prescribe them. Insight from genetics is beginning to explain some of those differences.

Patients with a particular genetic makeup do not effectively break down Plavix, an anticlotting drug. Variations in two genes affect how people re spond to the common blood thinner warfarin. Genetic testing provides a new way to understand which drugs will work for which patients, meaning people and insurers might have a new tool to avoid paying for drugs that may not work.

“We’re in a good place, theoretically, because we’re being hired to help people manage their prescriptions,’’ said Dr. Robert Epstein, chief medical officer of Medco.

Still, using genetic testing to better target drugs is controversial. Even as evidence has emerged that variations in a particular gene may change a person’s response to a drug, the evidence may not exist that changing the dose or drug leads to a better outcome or is more cost effective, given the cost of the test. The Food and Drug Administration has changed the labels of various drugs, sometimes mentioning a gene that may affect response to the drug but not always recommending or requiring a test.

“The FDA can label drugs to say that this medication is only indicated if you have this [genetic] finding,’’ as it does for the cancer drug, Herceptin, said Dr. Marc S. Williams, vice president of the American College of Medical Genetics. But in other cases it has not gone so far.

“Predicting the dose better does not translate automatically into better safety for patients,’’ Williams said.

The interest of pharmacy benefit management companies in personalized dosages is intriguing, he said, because they reach so many patients and can begin to collect data to better understand how drugs and genes interact. Medco has entered a partnership with the FDA to begin to answer some of those questions by collecting data and studying factors such as safety, physician participation, and the tests’ usefulness.

To advocates for personal medicine, the companies’ interest is a powerful vote of confidence.

“This is the most exciting thing in personalized medicine today, because Medco and CVS are big players with enormous impact in the field,’’ said Edward Abrahams, executive director of the Personalized Medicine Coalition, an education and advocacy organization, which is funded by diagnostic, pharmaceutical, and health insurance companies, and hospitals, among others. “The point of personalized medicine is to develop better efficacy, better outcomes, fewer adverse events, and lower systemic costs. The pharmacy benefits manager is interested in all of those things.’’

In Medco’s personalized medicine program, genetic testing is offered to patients prescribed the breast cancer drug tamoxifen or warfarin. Responses to both have been found to be affected by particular genes, although how and whether to test has been a subject of considerable debate within the medical community.

Warfarin, which can cause bleeding in high doses, is a common cause of emergency room visits for adverse drug reactions, according to the FDA. Variations in two genes have been shown to affect how people respond to the drug, indicating they may need a lower dose.

Having a variation of a gene involved in the metabolism of tamoxifen has been shown to increase the risk of a recurrent cancer, and knowing this could allow a physician to prescribe a different treatment.

In both cases, Medco does not require the physician to order a test in order to prescribe the drug, but it tells them a gene test is available.

An example of the potential benefit from the use of such information could come from one of the most-prescribed drugs, Plavix.

A 2008 study found that a variation in a gene that occurs in about a third of the population causes them to not respond as well to the drug because they do not metabolize it properly. The FDA changed the label to include the genetic risk last year. Last fall, Medco said it would compare Plavix with another drug, Effient, to see how a person’s genetic makeup affected his or her response to the drug. Because Plavix will lose its patent status in 2011, if it is found to be as effective as Effient for people with a particular genetic makeup, it could give patients who get a test a cheaper option.

“How can we help clients maintain the affordability of insurance and drugs and make the best outcome,’’ Epstein asked. “The problem is not with the science, it’s with the adoption.’’

Carolyn Y. Johnson can be reached at  


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