By Matthew E. Fink, MD

Professor and Chairman, Department of Neurology, Weill Cornell Medical College; Neurologist-in-Chief, New York Presbyterian Hospital

Dr. Fink reports he is a retained consultant for Procter & Gamble and Pfizer.

SOURCE: Johnstone SC, Amarenco P, Albers GW, et al for the SOCRATES Steering Committee and Investigators. Ticagrelor versus aspirin in acute stroke or transient ischemic attack. N Engl J Med 2016;375:35-43.

After ischemic stroke and transient ischemic attack, the risk of subsequent ischemic events is high during the first 90 days after the index event. The standard secondary preventive treatment has been a daily dose of aspirin. However, the benefit of this treatment, on a long-term basis, is only about a 20% lower rate of recurrent stroke compared to no preventive therapy. Therefore, other therapies have been sought that are more effective. Ticagrelor is an antiplatelet agent that reversibly binds and inhibits the P2Y12 receptor on platelets and is direct acting, and theoretically, should be more effective than either clopidogrel or aspirin. This trial was designed to test the effectiveness of secondary prevention with ticagrelor vs. aspirin.

An international double-blind, controlled trial was performed in 674 centers in 33 countries, and enrolled 13,199 patients with nonsevere ischemic stroke or transient ischemic attack. If subjects did not have a cardioembolic stroke, they were randomly assigned within 24 hours after symptom onset, in a 1:1 ratio, to receive either ticagrelor or aspirin daily, for days 2 through 90. The primary endpoint was the time to occurrence of stroke, myocardial infarction, or death within 90 days. During the 90 days of treatment, the primary endpoint occurred in 6.2% of patients treated with ticagrelor vs. 7.5% of patients treated with aspirin (hazard ratio, 0.89; 95% confidence interval, 0.78-1.0; 95% confidence interval, 0.78-1.01; P = 0.07). There was no difference in major bleeding episodes nor any difference in the incidence of intracranial hemorrhage.

In this trial, ticagrelor was not found to be superior to aspirin in reducing the rate of stroke, myocardial infarction, or death within 90 days, but there was a trend toward a reduced rate of ischemic stroke, that did not reach statistical significance.