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Reduced Plavix Efficacy Associated With Specific Gene Variants Confirmed In Two New Analyses, But Not In A Third.
By jeremyc | August 30, 2010
Source: DIA Daily
The Wall Street Journal (8/30, Winslow) reports that for patients with acute coronary syndrome, physicians often turn to Sanofi-Aventis and Bristol-Myers Squibb’s Plavix (clopidogrel) to prevent clot-induced strokes and heart attacks. However, a significant number of patients carry genetic variations that impede the drug’s effectiveness. While some believe a genetic test could help physicians make more accurate treatment decisions, others are wary. Cardiologist Spencer King, former president of the American College of Cardiology, added, “You can’t do a genetic test on an acute patient and get a result in time to change your mind.”
Now, two new studies are providing evidence that genetic testing may have limited value when considering a Plavix prescription, according to Reuters (8/30, Hirschler). The trials are especially significant because of the recent arrivals of Plavix generics to the market. There are no clear winners yet, however, as a third trial indicates that Plavix may indeed benefit patients who were previously thought to imperfect candidates due to their genetic make-up.
Still, Bloomberg News (8/30, Kresge) reports, Alfred Bove, the “immediate past president of the American College of Cardiology,” said, “Physicians don’t like complications.” He added, “If I told you there was an alternative to clopidogrel that worked the same way without the variations, they would jump on it.” But, after analyzing “gene variations in more than 10,000 patients who participated in the PLATO study,” an international team of researchers found that Brilinta (ticagrelor) “cut the risk of heart attacks, strokes, and death linked to heart disease more than Plavix, at a higher risk of spontaneous major bleeding, regardless of genetic variations.” In the second study, “funded by Lilly and Daiichi Sankyo” and also published in The Lancet, Harvard “researchers analyzed patients from the 2007 Triton trial to find that a genetic variation that diminished the effectiveness of Plavix didn’t have the same effect on Effient’s [prasugrel] potency.”
However, “in the CURE trial of patients with acute coronary syndromes without ST-segment elevation, clopidogrel significantly reduced the rate of cardiovascular death, MI, or stroke compared with placebo, regardless of CYP2C19 genotype (HR 0.71, 95% CI 0.60 to 0.84),” MedPage Today (8/29, Neale) reported. The paper published in the New England Journal of Medicine “contradicts previous findings leading the FDA to mandate a boxed warning on clopidogrel in March, about carriers of these variants who poorly metabolize the drug at standard doses and have higher cardiovascular event rates.” Nevertheless, “genotype-related efficacy issues may take a back seat to adherence as the main concern for clinicians,” Bove “said, pointing out that many patients on long-term clopidogrel treatment stop taking the drug.” He added, “That’s probably more of a problem than the genetic variation right now.”
The Wall Street Journal (8/30, Winslow) reports that for patients with acute coronary syndrome, physicians often turn to Sanofi-Aventis and Bristol-Myers Squibb’s Plavix (clopidogrel) to prevent clot-induced strokes and heart attacks. However, a significant number of patients carry genetic variations that impede the drug’s effectiveness. While some believe a genetic test could help physicians make more accurate treatment decisions, others are wary. Cardiologist Spencer King, former president of the American College of Cardiology, added, “You can’t do a genetic test on an acute patient and get a result in time to change your mind.”
Now, two new studies are providing evidence that genetic testing may have limited value when considering a Plavix prescription, according to Reuters (8/30, Hirschler). The trials are especially significant because of the recent arrivals of Plavix generics to the market. There are no clear winners yet, however, as a third trial indicates that Plavix may indeed benefit patients who were previously thought to imperfect candidates due to their genetic make-up.
Still, Bloomberg News (8/30, Kresge) reports, Alfred Bove, the “immediate past president of the American College of Cardiology,” said, “Physicians don’t like complications.” He added, “If I told you there was an alternative to clopidogrel that worked the same way without the variations, they would jump on it.” But, after analyzing “gene variations in more than 10,000 patients who participated in the PLATO study,” an international team of researchers found that Brilinta (ticagrelor) “cut the risk of heart attacks, strokes, and death linked to heart disease more than Plavix, at a higher risk of spontaneous major bleeding, regardless of genetic variations.” In the second study, “funded by Lilly and Daiichi Sankyo” and also published in The Lancet, Harvard “researchers analyzed patients from the 2007 Triton trial to find that a genetic variation that diminished the effectiveness of Plavix didn’t have the same effect on Effient’s [prasugrel] potency.”
However, “in the CURE trial of patients with acute coronary syndromes without ST-segment elevation, clopidogrel significantly reduced the rate of cardiovascular death, MI, or stroke compared with placebo, regardless of CYP2C19 genotype (HR 0.71, 95% CI 0.60 to 0.84),” MedPage Today (8/29, Neale) reported. The paper published in the New England Journal of Medicine “contradicts previous findings leading the FDA to mandate a boxed warning on clopidogrel in March, about carriers of these variants who poorly metabolize the drug at standard doses and have higher cardiovascular event rates.” Nevertheless, “genotype-related efficacy issues may take a back seat to adherence as the main concern for clinicians,” Bove “said, pointing out that many patients on long-term clopidogrel treatment stop taking the drug.” He added, “That’s probably more of a problem than the genetic variation right now.”
Topics: | Plavix |
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