On August 29 at the European Cardiovascular Society Congress meeting in Stockholm, Sweden, Dr. Guillaume Paré presented new research conducted by McMaster University that in fact contradicts earlier reports that Plavix (clopidogrel) does not work in people with a certain genetic make-up. Paré is the lead researcher and assistant professor of pathology and molecular medicine at the Michael G. DeGroote School of Medicine.

Clopidogrel is the world's second best-selling prescription drug with yearly sales of over $6 billion USD. It is used to reduce risk of heart attacks and strokes in 110 countries by tens of millions of patients.

The FDA (Food and Drug Administration) slapped a black box warning to physicians on the Plavix's usage insert packaging after an international team of scientists confirmed that clopidogrel may not have the same success in certain types of patients.

Paré said:

(Our findings) add a further layer of complexity to the FDA 'black box' warning and show that reported genetic variants have no effect in certain patient populations.

Following the FDA's warning, clopidogrel became the hot topic between cardiology professionals. Some American cardiologists initially called the FDA's swift labeling action rash. Others complained they were left without any clear direction on how to manage their patients.

Roughly 20% of the population carries the loss-of-function version of the gene involved in this building clopidogrel controversy.

Dr. Paré and colleagues from McMaster University conducted a genetic sub-study from two existing trials supported by Sanofi-Aventis and Bristol-Myers Squibb. The first trial, CURE (Clopidogrel in Unstable Angina to Prevent Recurrent Ischemic Events) consisted of 12,562 patients in 28 countries with acute coronary syndrome.

Results showed Plavix does in fact significantly reduce the risk of heart attack stroke and related fatalities. The ACTIVE (Atrial Fibrillation Clopidogrel Trial with Irbesartan for the Prevention of Vascular Events) trial of 7,554 patients with atrial fibrillation in 30 countries found clopidogrel in combination with conventional aspirin decreased the risk of cardiovascular ailments, and particularly strokes.

Paré continued:

We found the previously reported genetic variants had no effect at all (for patients) in either the CURE or ACTIVE trials. Also, our study design was a bit stronger from an epidemiology point of view.

Paré feels the positive results from McMaster's genetic sub-study come from studying multiple and varied patient populous sets. Further, the doctor stated that there is a need to exercise extreme caution as patient care integrates genetic observation and inclusion more and more.

Source: McMaster University

Sy Kraft

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