New study to examine genomics of anti-platelet therapy after coronary interventions

Which antiplatelet medication is best after a coronary stent? The Tailored Antiplatelet Therapy to Lessen Outcomes After Percutaneous Coronary Intervention (TAILOR-PCI) Study examines whether prescribing heart medication based on a patient's CYP2C19 genotype will help prevent heart attack, stroke, unstable angina, and cardiovascular death in patients who undergo percutaneous coronary intervention (PCI), commonly called angioplasty.

TAILOR-PCI, which began in 2013 with study teams at 15 hospitals in the U.S., Canada and South Korea and plans to enroll 5,270 patients, just received an additional $7 million from the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH), to complete the study. Twenty nine medical centers are now participating with more to be added soon. The randomized comparison of Plavix (clopidogrel bisulfate) and Brilinta (ticagrelor) was launched by Mayo Clinic Center for Individualized Medicine and the Department of Cardiovascular Diseases at Mayo Clinic in collaboration with Peter Munk Cardiac Centre, University Health Network, Toronto, and Spartan Bioscience, Ottawa.

"The NHLBI grant is validation of the importance of the question that needs to be answered: Is pharmacogenomics useful in prescribing individualized anti-platelet therapy after PCI," says Naveen Pereira, M.D., Mayo Clinic cardiologist and principal investigator of TAILOR-PCI. "This study will tell us whether this gene plays an important role in determining response to anti-platelet therapy after coronary interventions."

Michael Farkouh, M.D., M.Sc., cardiologist, Peter Munk Cardiac Centre, University Health Network, and principal investigator, describes this large, simple trial as "a true multinational collaboration designed to best inform clinical practice."

Yves Rosenberg, M.D., the NHLBI program officer for the study, and chief of the Atherothrombosis and Coronary Artery Disease Branch, added, "NHLBI is happy to support this important study, which we hope will contribute to the evidence needed to start delivering precision medicine in clinical settings. This trial could have global impact by potentially changing treatment recommendations for millions of individuals with coronary artery disease needing antiplatelet treatment after a percutaneous coronary intervention."

The costly and potential life-or-death question lingers after most of the 600,000 angioplasties performed every year in the U.S. The current standard of care after angioplasty is to prescribe clopidogrel for one year.

"Today, we do this regardless of a person's individual genotype, even though we have known for several years that variation in the CYP2C19 gene may diminish the benefit from the drug," Dr. Pereira says. "What we don't know — and why there is such confusion in the cardiovascular community — is whether these genetic differences affect long-term clinical outcomes."

Antiplatelet medication reduces the risk of heart attack, unstable angina, stroke and cardiovascular death after stent placement by reducing the possibility of blood clots around the surgical site.

Clopidogrel, however, remains ineffective until the liver enzyme CYP2C19 metabolizes the drug into its active form. Some alternative medications, including ticagrelor, do not require activation through the same genetic pathway. Ticagrelor has its own risks, says Dr. Pereira, including serious or life-threatening bleeding. In addition, ticagrelor costs approximately six to eight times as much and must be taken twice a day, compared with clopidogrel.

"Answering this question is important for the most appropriate and best patient care, and it also will help physicians and patients use health care dollars most responsibly," says Chet Rihal, M.D., chair of cardiovascular services for Mayo Clinic and study chair.