November 17, 2010 - Results from the GRAVITAS Trial found that doubling the maintenance dose of clopidogrel (Plavix) did not reduce the risk of further ischemic events after percutaneous coronary intervention (PCI). The study also reported patients with high residual platelet reactivity demonstrated almost twice the risk of ischemic events compared to patients without high residual platelet reactivity.
Patients were categorized as having high residual platelet reactivity based on the VerifyNow P2Y12 Test. The test is used to measure the antiplatelet effect of medications that reduce platelet reactivity by blocking the platelet P2Y12 receptor.
"The GRAVITAS findings do not support a uniform treatment strategy of high dose clopidogrel in patients with high residual platelet reactivity based upon a single platelet function test after stent implantation,” said Matthew J. Price, M.D., of the Scripps Translational Science Institute and Scripps Clinic in La Jolla, Calif., and principal investigator of the trial. “This is important as currently many physicians utilize a strategy of doubling the dose of clopidogrel the morning after the stent procedure. Alternative therapies or testing a patient multiple times to treat to a specific target of reactivity deserve consideration."
"The GRAVITAS trial provides further evidence of the association between high residual platelet reactivity, sometimes referred to as non-responsiveness, and the occurrence of cardiovascular events,” said Jeffrey R. Dahlen, Ph.D, vice president of clinical and regulatory affairs for Accumetrics “The trial demonstrated a strong trend towards greater risk of ischemic events in non-responders, which is consistent with prior reports. As we further analyze the data, we expect to release additional information that continues to support the value of platelet function testing."
The VerifyNow system is the first rapid and easy-to-use point-of-care system for measuring platelet reactivity to multiple antiplatelet agents. It is widely used where antiplatelet medications are prescribed to reduce the occurrence of future thrombotic events, such as heart attack and stroke. Clopidogrel is an oral antiplatelet agent sold under the brand name Plavix.
The GRAVITAS study is the first multi-center, placebo-controlled study to determine whether high maintenance dose of clopidogrel therapy reduces ischemic events post-PCI based on the VerifyNow test.
For more information: www.accumetrics.com