Prasugrel appears to be superior to clopidogrel as an antiplatelet agent in patients with acute coronary syndrome regardless of type of stent placed during angioplasty or timing of the procedure, according to a late-breaking clinical trial presented at the annual meeting of the American College of Cardiology.

Prasugrel reduced by more than half the risk of thrombosis inside the stent. Now a new analysis of data from the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel (TRITON-TIMI 38) reveals that the investigational drug maintains its edge over clopidogrel regardless of the type of stent, the amount of time since the stenting procedure, or the way stent thrombosis is defined.

For the main TRITON-TIMI 38 study, researchers recruited 13,608 patients who needed a stent from 707 medical centers in 30 countries. Patients were randomized to anti-platelet therapy consisting of either a 300-mg loading dose of clopidogrel before the procedure, followed by a maintenance dose of 75 mg daily for one year, or to a loading dose of 60 mg of prasugrel, followed by 10 mg daily for one year.

Stephen D. Wiviott, MD, Brigham and Women's Hospital, Boston, led the new stent analysis. Of the 12,844 patients who ultimately were treated with at least one coronary stent, 6,461 patients received only bare-metal stents and 5,743 patients received only drug-eluting stents. Overall, prasugrel reduced both 30-day stent thrombosis when compared with clopidogrel (0.64 percent vs. 1.56 percent) and late stent thrombosis (0.49 percent vs. 0.82 percent).

For bare-metal stents, the respective rates of stent thrombosis with prasugrel and clopidogrel were 1.3 percent vs. 2.4 percent, and for drug-eluting stents, 0.8 percent vs. 2.3 percent. Prasugrel's advantage remained highly statistically significant across a broad array of patient and procedural characteristics.