Even Less Aspirin With Ticagrelor-Based DAPT Safe After Stenting for ACS

SAN FRANCISCO -- For ticagrelor-based antithrombotic regimens after drug-eluting stent implantation for acute coronary syndrome (ACS), stopping aspirin within the first month appeared to be safer than continuing it in the T-PASS trial.

Ticagrelor (Brilinta) monotherapy after less than 1 month of dual antiplatelet therapy (DAPT) had a 2.8% composite rate of death, myocardial infarction, stent thrombosis, stroke, and major bleeding at 1 year compared with 5.2% among those who got a full 12 months of DAPT (HR 0.54, 95% CI 0.37-0.80), which met both noninferiority and superiority criteria for greater net clinical benefit with dropping aspirin early.

The difference was driven by a significant reduction in major bleeding in the group with a short time on aspirin (1.2% vs 3.4%, HR 0.35, 95% CI 0.20-0.61).

The short DAPT regimen thus appeared to be a "reasonable alternative," Myeong-Ki Hong, MD, PhD, of Severance Hospital and Yonsei University College of Medicine in Seoul, South Korea, reported at the Transcatheter Cardiovascular Therapeutics (TCT) meeting hosted by the Cardiovascular Research Foundation.

The findings were simultaneously published in Circulation.

T-PASS adds "very consistently" to the trial experience of almost 22,000 patients in dropping aspirin from ticagrelor-based DAPT across now five trials, noted TCT session study discussant Marco Valgimigli, MD, PhD, of Cardiocentro Ticino in Lugano, Switzerland, suggesting a "a very significant and clinically very convincing bleeding risk reduction, and I would like to underline, major bleeding risk reduction."

TICO and TWILIGHT trials had demonstrated that ticagrelor monotherapy after 3 months of DAPT significantly reduced bleeding risk without increasing ischemic events after percutaneous coronary intervention (PCI) in ACS or high-risk PCI patients.

What's different about this trial was its higher risk patient population, with almost 40% having ST-segment elevation MI (STEMI), as well as the even shorter duration and the use of ticagrelor instead of clopidogrel, which had shown increased ischemic risk in some studies, noted TCT press conference moderator Ajay Kirtane, MD, of NewYork-Presbyterian/Columbia University Irving Medical Center in New York City.

"This really gets us to us changing the guidelines in the United States to really push the envelope on shortening DAPT, because of the safety of the third and fourth generation drug-eluting stents and [the potential for] minimizing risk to patients by shortening that period of time of risk down to less than 1 month," said press conference panelist John Messenger, MD, director of the University of Colorado Cardiac Catheterization Labs in Aurora.

While there shouldn't be any issues with generalizing the findings to U.S. populations from the South Korean population studied in T-PASS, these weren't high bleeding risk patients, emphasized press conference panelist B. Hadley Wilson, MD, president of the American College of Cardiology. "I think we need to just see how it fits across all patient groups."

Hong's group acknowledged: "Low event rates which may suggest enrollment of relatively non-high-risk patients should be considered in interpreting the trial."

Indeed, TCT late-breaking trial session study panelist Roisin Colleran, PhD, of the Cardiovascular Research Institute Dublin in Ireland, questioned the external validity of the trial "in that patients seem to be quite low risk." Low 1-year mortality and Bleeding Academic Research Consortium (BARC) 3-5 bleeding rates were much lower than other trials that have looked at ticagrelor plus aspirin for 12 months. Colleran contrasted 12-month major bleeding rates of about 5% in the ISAR-REACT 5 trial with prasugrel-based DAPT versus about 3% in the continued ticagrelor-based DAPT group in T-PASS.

The trial included 2,850 patients at 24 centers in South Korea who got the Orsiro biodegradable polymer sirolimus-eluting stent for acute coronary syndrome within the 4 weeks prior to implantation. After a loading dose of aspirin and ticagrelor for those not already on the drugs, participants got 100-mg aspirin and 90-mg ticagrelor twice daily. They were randomized to either continue that regimen for 12 months or to discontinue aspirin at the operator's discretion, suggested to be at the first visit after discharge (within 1 month after the index procedure, median 16 days), and continue ticagrelor 90 mg twice daily alone to 12 months.

The first follow-up visit was scheduled at 1 to 4 weeks and subsequently at 3, 6, and 12 months after stenting. Concomitant use of other antiplatelet agents or anticoagulants was not allowed.

Early aspirin discontinuation didn't alter occurrence of major adverse cardiac events (a composite of cardiovascular death, MI, stent thrombosis, and ischemia-driven target-vessel revascularization), at 1.5% versus 2.2% (HR 0.68, 95% CI 0.39-1.18).

Limitations included lack of statistical power for components of the primary endpoint, especially ischemic events, as well as the open-label design.

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