ACC, AHA release report in response to FDA boxed warning for clopidogrel

Members of the American College of Cardiology Foundation and the AHA released a report yesterday to provide recommendations for treating patients with acute and chronic CAD following the release of the FDA’s boxed warning for clopidogrel earlier this year. The new safety information is for patients whose genetic make-up may compromise their ability to metabolize the drug.

“We have pieces of information, but we need to try to connect the dots, and that’s what we have tried to do [in this report],” David Holmes, Jr, MD, professor of medicine at the Mayo Clinic, said in a press release.

Information on the specific genetic variations that may affect clopidogrel (Plavix; Sanofi Aventis, Bristol Myers Squibb) metabolism is increasing, but evidence for the development of recommendations for testing is lacking, and questions still remain, including when to test, which tests to use and whether the tests are reimbursable.

The report is aimed to help clinicians develop the optimal treatment plan for each patient. Some recommendations include:

Adherence to existing evidence-based guidelines from the ACC, AHA or other professional societies for using antiplatelet therapies should remain the foundation of care. If clopidogrel is prescribed, health care providers should help ensure that patients take it as prescribed.
Clinicians must be aware that in certain patients with either acute or chronic CAD, genetic variability in response to clopidogrel can affect its inhibition of platelet function.
Careful clinical judgment, including weighing the risks and benefits, is needed in considering all therapies. The new boxed warning points out that for clopidogrel, if there is a lack of efficacy, the consequences can potentially result in fatal outcomes.
Results from ongoing clinical trials in large groups of patients will provide more information about the predictive value of genetic testing and better inform the role genotyping might play in personalizing medicine and optimizing outcomes.
Genetic testing to determine if a patient is a “poor metabolizer” may be considered before starting clopidogrel therapy in patients believed to be at moderate or high risk for poor outcomes (eg, patients undergoing elective high-risk PCI procedures).
Using alternative antiplatelet therapies or altering the dosing of clopidogrel may be reasonable options in patients who experience an adverse event while taking clopidogrel and have been taking the drug as prescribed.

The report also emphasizes the importance of careful clinical judgment in each patient and compliance with current antiplatelet therapy guidelines. In addition, patients should not stop taking clopidogrel unless told to do so by their health care professional.

“While it would be nice to match a specific drug to each patient, the science for personalized medicine isn’t there yet. What we are left with are different groups of patients, different medicines and an attempt by clinicians to carefully balance the risks and benefits of all the different therapeutic strategies to optimize outcomes,” said Holmes, who is also a member of the Cardiology Today Editorial board.

The report will be published in the July 20, 2010 issues of the Journal of the American College of Cardiology and Circulation: Journal of the American Heart Association. The report will also be available on the ACC and AHA websites.

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