NEW YORK (Reuters Health) – In patients with acute coronary syndrome undergoing percutaneous coronary intervention (PCI) prasugrel shows the most favorable benefit-to-risk ratio in the core group of patients for whom this platelet inhibitor has been approved, researchers report in an August 14th on-line paper in the American Journal of Cardiology.
“This study,” Dr. Stephen D. Wiviott told Reuters Health by email “is an analysis of a group of patients without stroke, less than 75 years old and greater than 60 kg identified as being a core group for the use of prasugrel by regulatory agencies.”
Dr. Wiviott of Brigham and Women’s Hospital and Harvard Medical School, Boston and colleagues note that the TRITON-TIMI 38 study involving more than 13,000 patients showed that prasugrel decreased ischemic events compared to standard clopidogrel, but with more bleeding.
Subsequently both the US Food and Drug Administration and the European Medicines Agency approved prasugrel. Contraindications were in patients with previous stroke or transient ischemic attack. Limited use or reduced dosage was recommended in patients 75 or more years old and weighing less than 60 kg.
The researchers examined data from the study in light of these recommendations. The core group of 10,804 patients who were treated with prasugrel had a clinically significant and robust decrease in the primary end point of cardiovascular death, myocardial infarction, or stroke (8.3% versus 11.0%). In the limited use group of 2149, efficacy was also limited (15.3% versus 16.3%).
For major bleeding not related to coronary artery bypass grafting, there were tendencies to higher rates with prasugrel in core patients (1.9% versus 1.5%) and in the limited group (4.1% versus 3.4%).
As Dr. Wiviott pointed out, the core “population had a marked reduction in ischemic events with prasugrel compared to clopidogrel. More bleeding was also observed with prasugrel treatment.”
However, when the end point of all-cause death, myocardial infarction, stroke and major bleeding was considered, the results were very much in favor of the core patients given prasugrel (10.2% versus 12.5%). The effect was neutral in the limited-use group (19.5% vs. 19.7%).
The 518 patients in whom the agent was contraindicated did poorly with regard to efficacy and safety.
The researcher note that patients enrolled in clinical trials tend to be at lower risk than those seen in practice, but conclude that “use of prasugrel in a core clinical cohort that has been defined by regulatory action will maximize the benefit of prasugrel and limit the risk of adverse outcomes.”