A Genetic Variation Makes Plavix Less Effective
1 CommentBy Ed Silverman // December 23rd, 2008 // 5:33 am
Heart attack survivors who are younger than 45 and have a common genetic variation were more likely to die or have a serious heart problem while taking the Plavix blood thinner than those without the variation, according to a study in The Lancet. The drug was less effective in these people and also raised the risk of blood clots for those carrying the variation who had stents inserted.
The findings highlight the importance of factors that can affect the response to Plavix but researchers cautioned it was too soon to start genetically testing patients for the variation without further study. “Thse findings need to be independently replicated before being extrapolated to older patients or those of non-European ancestry,” the researchers concluded.
They examined a gene known as CYP2C19, which plays a key role in determining how individuals metabolize commonly prescribed drugs, including treatments for depression, heart disease, high blood pressure and hyperactivity (here is the study).
Their study between 1996 and 2008 followed 259 men and women younger than 45 years old who survived a heart attack and were on the drug for just over a year. A little more than a quarter of the volunteers had the genetic variation, about the same level as in Western populations but less than in Asia where the mutation is more common, according to the study.
The researchers found the genetic variation appeared to increase the risk of complications and premature death compared to people without the change. When looked at alone, the researchers also found that stent blockage was six times more likely to occur in people with the variation. Stents are wire mesh tubes inserted into coronary arteries that have been cleared of blockages.
In an accompanying comment, Robert Storey of the Cardiovascular Research Unit at the University of Sheffield School of Medicine, wrote: “Although the fascinating observations of Montalescot and co-workers focus attention on the importance of factors that influence the response to clopidogrel, genotyping of patients with acute coronary syndrome is not necessarily the appropriate solution without further work to validate such an approach.”
An assist goes to Reuters
Agency Employee
Talk about timing.
Here’s my post from yesterday on another thread.
December 22nd, 2008 2:03 pm
http://www.pharmalot.com/2008/12/pdl-moves-headquarters-near-the-ceos-home/#comment-385408
“This past week the press indicated that approvals will likely get easier in the next year or two. (Guess why.) Plus Von Eschenbach and FDA management have indicated in the past that things will get better for companies under the critical path initiative by 2010, and we will see the fruit of personalized medicine by 2015. These last statements were accompanied by statements that co-marketing of drug and devices for personalized medicine will save drugs from being removed from the market as well as extend patent protections. (statements made June 2007)”
It’s not only efficacy, but knowledge about unsafe drugs that this will save. The companies and FDA are currently intentionally putting unsafe drugs on the market. Then when Woodcock’s safety first initiative finds (already known) toxicities after approval genetic tests will be used to keep the drug on the market but in a restricted population.
The genetic testing will be a windfall ($) for the companies but in the interim they will have sold to many more people and the genetic tests will also diminish fear and keep sales up as well as then extend patent protections. Plus with preemption no one can be held responsible for truly horrific and widespread toxicities.