Pharmacogenetic testing must become routine, UF Health researchers say

GAINESVILLE, Fla. — A simple genetic test could help prevent life-threatening complications for the millions of Americans who take a common blood clot-preventing medication, prompting University of Florida Health researchers to call for major heart health organizations to add the testing to their guidelines.

Up to 30% of Americans, and as many as 60% of those with Asian ancestry, carry genetic variations that reduce the effectiveness of clopidogrel, more widely known as Plavix — a drug used to prevent blood clots after a heart attack or angioplasty.

Pharmacogenetic testing, which examines how a person’s DNA influences their response to medications, can identify whether clopidogrel will work as intended or leave patients vulnerable to heart attack, stroke or death, especially for those with a high bleeding risk.

A group of UF Health researchers wrote a commentary for the Journal of the American Heart Association, published May 6, suggesting that pharmacogenetic testing should be recommended by major heart associations before practitioners prescribe clopidogrel.

The opinion piece was written by Lari Cavallari, Pharm.D., chair of the UF Department of Pharmacotherapy and Translational Research and the Debbie DeSantis Excellence Professor, and Dominick Angiolillo, M.D., Ph.D., chief of the Division of Cardiology at UF Health Jacksonville, along with other American and European experts in pharmacogenetics and cardiology.

Clopidogrel made headlines when the state of Hawaii sued the drug’s makers for not warning patients about the drug’s reduced effectiveness for those with a certain genotype, called CYP2C19 — and won.

In 2024, the American Heart Association published a scientific statement from experts recommending that pharmacogenetic testing be explored for patients with cardiac issues. To Cavallari and her co-authors, it’s mystifying why the latest guidelines from the AHA and other heart organizations make no recommendations about genotyping before prescribing clopidogrel despite growing evidence that the technique improves patient outcomes.

“It’s indisputable that this particular genotype influences the effectiveness of clopidogrel, a very commonly prescribed heart medication. There are data from clinical trials and observational studies to support genotyping and its ability to improve patient outcomes and decrease bleeding risk if you use it to guide therapy.

“In fact, there are more data now to support genotyping than when the last guidelines provided a recommendation that genotyping could be considered. Yet, there’s less attention on the topic,” said Cavallari, who helped expand access to pharmacogenetic testing as director of the UF Health Precision Medicine program, establishing it as a standard of care across UF Health practices.

Available through many commercial laboratory vendors and covered by insurance in most states, genotyping using a blood or saliva sample also can predict how a patient will respond to proton pump inhibitors, some antidepressants and antifungal drugs. The U.S. Food and Drug Administration recently approved a rapid genotyping platform with test results available in about one hour.

“Many of the barriers that once limited CYP2C19 genotyping in clinical practice have now been removed,” Cavallari said. “The process is similar to other routine laboratory tests we rely on, except this one only needs to be done once.”