Genetic testing for cardiovascular therapy 'underutilized'

Genetic testing for cardiovascular therapy 'underutilized'

A new study suggests that genetic testing used to determine the correct prescriptions for cardiovascular therapy is "underutilized."

Researchers say their findings are likely to reflect the "unclear impact and physician uncertainty" in terms of evolving treatment using pharmacogenomics - the analysis of how an individual's genetic make-up affects their response to drugs.

For the study, published in the journal Circulation: Cardiovascular Quality and Outcomes, investigators from US drug company CVS Caremark and Brigham and Women's Hospital in Massachusetts analyzed prescribing patterns for patients suffering from either acute coronary syndrome (ACS) or percutaneous coronary intervention (PCI).

A study conducted on patients who were prescribed clopidogrel for cardiovascular therapy suggested that doctors are 'underutilizing' genetic testing to determine whether the drug is suitable for their patients.

All patients had been prescribed the antiplatelet medication clopidogrel. According to the researchers, clopidogrel has been shown to significantly reduce the risk of serious cardiovascular events in patients with ACS and PCI, but they note that there is wide variability in how patients respond to this drug.

The US Food and Drug Administration (FDA) recommends that patients do not use clopidogrel if they are poor metabolizers of the drug. In other words, patients should not use clopidogrel if they are not able to eliminate the drugs from their body quickly.

The FDA has also recently changed box warnings to reflect this and to encourage health care professionals to move toward alternative antiplatelet strategies or other dosing methods for those who are poor metabolizers.

Genetic tests 'declined or ignored'

For the study, the doctors of the patients were offered access to a genetic test, called CYP2C19, in order to determine their patients' abilities to metabolize clopidogrel. Some of the patients were also offered the genetic testing directly.

Almost 500 patients completed the test, while prescribers declined genetic testing in 25% of all cases. Less than 10% of patients declined the test when offered it directly.

Of the 500 patients who had the testing, one-third were found to be poor metabolizers of drugs.

However, the study findings revealed that although patients who had this genetic testing were more likely to have their prescription of clopidogrel changed, compared with patients who did not have the genetic test, only 20.5% of poor metabolizers were swapped to another drug or had their antiplatelet therapy boosted.

'Lack of knowledge and understanding'

The researchers say their findings demonstrate doctors' lack of knowledge and uncertainty in how they should respond to genetic testing.

Niteesh K. Choudhry, associate physician at the Division of Pharmacoepidemiology and Pharmacoeconomics at Brigham and Women's Hospital and senior author of the study, says:

While there is significant uncertainty about how clinicians should respond to the results of genetic testing for antiplatelet drugs, this study clearly shows that patients and their doctors need more guidance and education about how best to apply these results to improve patient outcomes."

Troyen A. Brennan, executive vice president and chief medical officer of CVS Caremark and co-author of the study, says that the medical world is entering an age where tailored treatment regimens for individual patients can be created, but they will only be successful if health care professionals and patients can understand and act on the results.

"This research shows there is an opportunity to improve upon the information doctors and patients receive on this evolving topic so that they can make the best treatment decisions," he adds.

Last year, reported on research from the American Heart Association and the American College of Cardiologists suggesting that there is insufficient evidence to support clopidogrel genetic testing.

We Took A DNA Test • The Test Friends (Video Medical And Professional 2020).

Section Issues On Medicine: Cardiology