Clay Johnston, MD, PhD: Ticagrelor DAPT and THALES Results

July 27, 2020

S. Claiborne Johnston discusses the results of the phase 3 THALES trial examining use of ticagrelor dual antiplatelet therapy for reducing subsequent stroke in patients with AIS or TIA.

Results of the phase 3 THALES atrial examining use of ticagrelor (Brilinta) in patients who an acute ischemic stroke or transient ischemic attack (TIA) suggest twice-daily use with aspirin was linked to reductions in stroke and death, both as individual and composite end points.

Just months after receiving approval for cardiovascular risk prevention in those without a history of cardiovascular disease, results of the latest phase 3 trial assessing ticagrelor add further excitement around the robustness and benefit of the P2Y12 inhibitor in treatment of a slew of cardiovascular conditions.

“Results from the phase 3 THALES trial confirm that aspirin plus Brilinta has the potential to be a new effective treatment option for these high-risk patients and we look forward to continuing discussions with regulatory authorities,” Mene Pangalos, PhD, executive vice president, BioPharmaceuticals R&D, AstraZeneca, said in a statement.

Designed as a randomized, placebo-controlled, double-blind trial, THALES compared ticagrelor dual antiplatelet therapy to aspirin alone in patients with mild-to-moderate acute noncardioembolic ischemic stroke or TIA not undergoing thrombolysis or thrombectomy. In total, 11,016 patients were enrolled and randomized in a 1:1 ratio to either group.

The primary end point of the trial, which was a composite of stroke or death within 30 days, occurred in 5.5% OF patients in the ticagrelor group compared to 6.6% in the aspirin alone group (HR, 0.83; 95% CI, 0.71-0.96; P=.02). In regard to secondary outcomes, ischemic stroke occurred in 5% of the ticagrelor group c imparted to 6.3% of the aspirin alone group (HR, 0.79; 95% CI, 0.68-0.93; P=.004).

When assessing the safety of ticagrelor dual antiplatelet therapy, investigators found no significant difference between the groups for incidence of disability (OR, 0.98; 95% CI, 0.89-1.07; P=.61). Investigators pointed out severe bleeding events occurred in 0.5% of the ticagrelor group compared to 0.1% of those randomized to aspirin alone (HR, 3.99; 95% CI, 1.74–9.14; P=.001).

Results of the trial come soon after AstraZeneca announced the filing of a supplemental new drug application (sNDA) for the agent for the reduction of subsequent stroke in patients who experienced an acute ischemic stroke or transient ischemic attack.

For more on the results of the phase 3 THALES trial and the sNDA from AstraZeneca, Practical Cardiology reached out to principal investigator S. Claiborne Johnston, MD, PhD, dean of the Dell Medical School at the University of Texas at Austin.

This study "Ticagrelor and Aspirin or Aspirin Alone in Acute Ischemic Stroke or TIA," was published in the New England Journal of Medicine.