SAN DIEGO, Sept. 28 /PRNewswire/ -- A new blood test for measuring the effects of one of the most commonly prescribed drugs in the United States has just been cleared by the Food and Drug Administration. The drug is Plavix(R) (clopidogrel) and it is taken by almost 10 million Americans to help prevent a potentially life-threatening heart attack or stroke.
Now, for the first time there is a simple and reliable way to test for Plavix response. VerifyNow(TM) P2Y12 is a fast, easy to perform blood test specifically designed to measure the effects of Plavix on platelets, the blood cells primarily responsible for clotting. Inhibiting the function of platelets is how Plavix exerts its cardioprotective effects.
Numerous studies have demonstrated the benefit of Plavix, but new research also indicates that from 5 to 30 percent of patients do not respond adequately to the drug. The medical consequences can be dramatic: Patients who are nonresponsive to Plavix are at much greater risk for a serious cardiovascular event that includes not only heart attack or stroke but also blockage of coronary stents. The most recent study linking response to Plavix with patient outcomes was published just this month in the Journal of the American Medical Association. It suggests that response to Plavix is an important factor in reducing cardiovascular events after coronary intervention.
Because of these concerns, nonresponsiveness to Plavix and other antiplatelet agents has become a subject of much attention in the medical community. Increasingly, physicians are beginning to focus more aggressively on how this clinical problem should be monitored and managed.
"We're now developing an understanding that, as for every other medicine, not all patients respond equally well to Plavix," said Daniel Simon, MD, associate director of interventional cardiology at Boston's Brigham and Women's Hospital. "We don't prescribe other drugs and just assume they're working. We test for the effects of cholesterol drugs and blood pressure drugs, we monitor response to the anticoagulant warfarin. We need to start adopting a similar paradigm for antiplatelet therapies such as aspirin and Plavix."
Monitoring Plavix response also has economic implications. A month's supply of the drug costs more than $100. Given the number of patients who may not respond, this could represent more than $1 billion in health care spending without any corresponding benefit.
"Plavix is a very effective medication for preventing strokes and heart attacks," notes Mark Alberts, MD, professor of neurology at Northwestern University Feinberg School of Medicine and director of the stroke program at Northwestern Memorial Hospital in Chicago. "However, in a certain percentage of patients the blood thinning effects of Plavix may not be optimal. The VerifyNow test provides physicians with an important tool to help identify these patients and plan appropriate therapy."
In less than 15 minutes, VerifyNow gives one, easy to understand result that indicates if a person is responding effectively to Plavix or if they are not. The test is inexpensive and is covered by Medicare as well as by many insurance providers.
Importance for Surgical Care
VerifyNow P2Y12 has implications in other areas of medicine as well. For example, the test can help doctors determine if a patient can safely undergo surgery. Medical guidelines recommend that a person stop taking Plavix for five days prior to an operation to enable clotting function to return to normal and to reduce the risk of excessive bleeding during or after the procedure. However, this means that surgery often must be delayed. Furthermore, withholding Plavix can put patients at increased risk for a heart attack or stroke while they are waiting to undergo their operation.
Such a situation occurred recently when former President Clinton needed heart surgery. His doctors waited several days before performing the bypass operation to ensure that the antiplatelet drugs he had been taking were cleared from his system.
"The Plavix test removes the guesswork about whether it's safe to go to surgery," said Christopher Cannon, MD, associate physician in the cardiovascular division of Brigham and Women's Hospital and a leading cardiovascular researcher. "Having information about clotting status allows us to proceed with the operation the day that function returns to normal, rather than routinely waiting five days in every case. This could dramatically reduce surgical delays for patients taking Plavix."
About Accumetrics (www.accumetrics.com)
Accumetrics develops, manufactures, and markets the VerifyNow(TM) System, a comprehensive system for the assessment of platelet function. Modulation of platelet function plays a critical role in effectively treating cardiovascular, cerebrovascular, and peripheral vascular disease. VerifyNow is the only rapid platelet function test shown to correlate with clinical outcomes. The tests provide doctors with an easy to use, automated, rapid and accurate way to monitor platelet function to optimize the effectiveness of antiplatelet therapies and to guide treatment decisions in patients who may be at risk of bleeding complications. Accumetrics markets VerifyNow(TM) tests for aspirin, Plavix(R) and GP IIb/IIIa inhibitors.
NOTE: Plavix(R) is a registered trademark of Sanofi-Synthelabo.
Accumetrics