Stopping Aspirin Within 1 Month After Stenting for Ticagrelor Monotherapy in Acute Coronary Syndrome: The T-PASS Randomized Noninferiority Trial

Background: Stopping aspirin within 1 month after implantation of a drug-eluting stent (DES) for ticagrelor monotherapy has not been exclusively evaluated for patients with acute coronary syndrome (ACS). The aim of this study was to investigate whether ticagrelor monotherapy after <1 month of dual antiplatelet therapy (DAPT) is noninferior to 12 months of ticagrelor-based DAPT for adverse cardiovascular and bleeding events in patients with ACS. Methods: In this randomized, open-label, non-inferiority trial, 2850 patients with ACS who underwent DES implantation at 24 centres in South Korea were randomly assigned (1:1) to receive either ticagrelor monotherapy (90 mg twice daily) after <1 month of DAPT (n=1426) or 12 months of ticagrelor-based DAPT (n=1424) between Apr 24, 2019, and May 31, 2022. The primary endpoint was the net clinical benefit as a composite of all-cause death, myocardial infarction, definite or probable stent thrombosis, stroke, and major bleeding at 1 year after the index procedure in the intention-to-treat population. Key secondary endpoints were the individual components of the primary endpoint. Results: Among 2850 patients who were randomized (mean age, 61 years; 40% ST-elevation myocardial infarction), 2823 (99.0%) completed the trial. Aspirin was discontinued at a median of 16 days (interquartile range, 12 to 25 days) in the group receiving ticagrelor monotherapy after <1 month of DAPT. The primary endpoint occurred in 40 patients (2.8%) in the group receiving ticagrelor monotherapy after <1-month DAPT, and in 73 patients (5.2%) in the ticagrelor-based 12-month DAPT group (hazard ratio [HR], 0.54 [95% CI, 0.37–0.80]; P <0.001 for noninferiority; P =0.002 for superiority). This finding was consistent in the per-protocol population as a sensitivity analysis. The occurrence of major bleeding was significantly lower in the ticagrelor monotherapy after <1-month DAPT group compared with the 12-month DAPT group (1.2% versus 3.4%; HR, 0.35 [95% CI, 0.20–0.61]; P <0.001). Conclusions: This study provides evidence that stopping aspirin within 1 month for ticagrelor monotherapy is both noninferior and superior to 12-month DAPT as for the 1-year composite outcome of death, myocardial infarction, stent thrombosis, stroke, and major bleeding, primarily due to a significant reduction in major bleeding, among ACS patients receiving DES implantation. Low event rates which may suggest enrolment of relatively non-high-risk patients should be considered in interpreting the trial.