Accumetrics Announces Publication of GRAVITAS Primary Results in JAMA
Evaluation of Alternative Treatment Strategies Incorporating Platelet Function Testing Recommended
SAN DIEGO, March 15, 2011 -- Accumetrics, Inc., developer of the VerifyNow® System, the point-of-care system for measuring platelet reactivity to multiple antiplatelet agents, announced today that the primary results of the GRAVITAS trial have been published in The Journal of the American Medical Association(1).
First presented at the American Heart Association's Annual Scientific Sessions in November 2010, the results refute a "one-size fits all" strategy of uniformly doubling the dose of clopidogrel (Plavix®) over six months for patients with high on-treatment platelet reactivity (low response) after taking a standard dose of the commonly prescribed antiplatelet drug.
While there was a modest reduction in platelet reactivity in GRAVITAS patients receiving a 6-month double dose of Plavix compared to the standard dose, it was not sufficient to impact overall outcomes, leading the authors to suggest that more potent platelet inhibition may have been beneficial.
Further, and consistent with numerous previous studies, the trial demonstrated an association between high on-treatment platelet reactivity and the occurrence of adverse cardiac events such as death, heart attack and stent thrombosis.
"The GRAVITAS findings do not support a uniform treatment strategy for patients with high on-treatment platelet reactivity," said Matthew J. Price, MD, of the Scripps Translational Science Institute and Scripps Clinic in La Jolla, CA, lead author of the article and Principal Investigator of the GRAVITAS trial. "Rather than prescribing a fixed, higher dose of clopidogrel based on a single post-PCI platelet function test, we need to consider alternative treatment strategies that incorporate platelet function testing, such as using more potent antiplatelet agents or repeated testing to a specific target of reactivity."
The article reports that 41% of patients in the GRAVITAS trial had high on-treatment platelet reactivity after receiving Plavix®. This is consistent with previous studies that show that up to 1 in 3 patients may not be responding adequately to their antiplatelet therapy. Numerous factors are associated with low platelet response, including pre-existing health conditions such as diabetes, interference from other medications, non compliance and genetics.
(1) Price MJ, Berger PB, Teirstein PS, et al. Standard- vs High-Dose Clopidogrel Based on Platelet Function Testing After Percutaneous Coronary Intervention. JAMA.2011;3051097-1105.