In the phase III THALES trial, the risk of the primary composite endpoint of stroke and death was reduced with ticagrelor in combination with aspirin taken for 30 days after acute ischemic stroke or transient ischemic attack (TIA), compared to aspirin alone. Preliminary safety results were reported with an increased bleeding rate in the ticagrelor plus aspirin arm compared to the aspirin arm of the study.

THALES is a randomized, placebo-controlled, double-blinded, international, multicenter, event-driven trial and investigated whether ticagrelor (90mg used twice daily) together with aspirin is superior to aspirin alone in preventing the composite of stroke and death in patients with minor acute ischemic stroke or high-risk TIA. More than 11,000 patients were randomized within 24 hours of onset of acute ischemic stroke or high-risk TIA symptoms. All patients received open-label aspirin 330-325mg on day 1 and 75-100mg once daily on day 2-30. Patients received ticagrelor 180mg loading dose on day 1, followed by 90mg twice daily on day 2-30, or matching placebo. The primary efficacy outcome was time the composite endpoint of stroke and death at 30 days. The primary safety outcome was the time to first severe bleeding event. Patients were followed for an additional 30 days on standard of care.

Source: Press release AstraZeneca, January 27, 2020