The study received no industry support. Dr. Park said that he and his associates had no disclosures.
Dr. Dangas reported financial relationships with several pharmaceutical and device companies, including Daiichi-Sankyo, Sanofi-Aventis, Boston Scientific, AstraZeneca, and Cordis. Dr. Mauri reported receiving consulting fees or honoraria from Cordis and Medtronic Vascular. Dr. Kereiakes reported financial relationships with Reva Medical, Eli Lilly, Boston Scientific, Cordis, Devax, and Abbott Vascular, Amylin, and Daiichi Sankyo, among other drug and device makers.
My Take
Results Won't Change My Practice
Despite the study's limited power, it generates some interesting hypotheses. Perhaps we need to consider the level of risk that patients face from major adverse events following coronary stenting with DES when evaluating dual antiplatelet therapy. The new results suggest that in low-risk patients this balance tips in favor of stopping dual antiplatelet drug therapy a year after stenting. It's not clear what mechanism might produce the apparent risk from clopidogrel treatment beyond 1 year in this study.
Asian populations have a high prevalence of cytochrome P2C19 genes that produce little or no active enzyme needed to metabolize clopidogrel to its active form. This may mean that many patients in the study were genetically unable to benefit from clopidogrel treatment.
The new results suggesting that low-risk patients exist who may not benefit from continued clopidogrel treatment, are not convincing. I have sufficient uncertainty that I'm not willing to change my practice, even in low-risk patients. My approach has been to have a low threshold for continuing dual-antiplatelet therapy in DES patients. Until now, all of the data supporting this approach came from observational studies. This is no substitute for prospective, controlled studies, so the Korean study is a laudable first step. What's needed are larger studies with longer follow-up, such as study the Dual Antiplatelet Therapy (DAPT) study, with an expected enrollment of more than 20,000 patients.
DR. ELLIOTT M. ANTMAN is a professor of medicine at Harvard Medical School in Boston. He was principal investigator for TRITON-TIMI 38, the pivotal trial of prasugrel, sponsored by Daiichi-Sankyo. He has financial relationships with Sanofi-Aventis, Momenta, and Eli Lilly, and has received research grants from 22 companies.
