Potential New Option: 1-Month DAPT Post DES, Then Aspirin Alone

Bruce Jancin

November 24, 2020

One month of dual-antiplatelet therapy followed by aspirin monotherapy in patients who've received a drug-eluting stent proved noninferior to 6-12 months of DAPT for a composite 1-year endpoint of cardiovascular events or major bleeding in the large, randomized One-Month DAPT trial.

This is the first test of such a strategy. Other trials of short-course DAPT, such as the successful TWILIGHT trial, have dropped the aspirin and continued the P2Y12 inhibitor. But aspirin monotherapy after a single month of DAPT is an attractive alternative in patients undergoing PCI for noncomplex lesions, Myeong-Ki Hong, MD, PhD, said in presenting his results at the American Heart Association scientific sessions.

"In everyday clinical practice, people receiving P2Y12 receptor blockers usually complain of several episodes of minor bleeding. And the cost. Those are strong factors in patient noncompliance," he said, adding, "I think aspirin monotherapy is more comfortable for the physician and the patient."

The One-Month DAPT trial included 3,020 patients who underwent percutaneous coronary intervention with drug-eluting stents (DES) at 23 Korean centers. They were split roughly 60/40 between patients with stable angina and those with acute coronary syndrome involving unstable angina. Patients with complex coronary lesions or acute MI were not eligible for enrollment. Participants were randomized to receive either the polymer-free drug-coated BioFreedom stent, in which case they got 1 month of DAPT followed by 11 months of aspirin antiplatelet monotherapy, or they received 6 or 12 months of DAPT in conjunction with a thick-strut BioMatrix or an Ultimaster polymer-based DES. The reason for using different stents in the two study arms is that only the polymer-free stent completes drug release within 1 month; other contemporary DESs release their drug for 3-4 months, and it's risky to discontinue one of the antiplatelet agents during drug elution, said Hong, professor of cardiology at Yonsei University in Seoul, South Korea.

Patients With Stable Angina Fared Best

The primary endpoint in this noninferiority trial was the 1-year composite of cardiac death, MI, target vessel revascularization, stroke, or major bleeding. The incidence was 5.9% in the 1-month DAPT group, statistically noninferior to the 6.5% figure in the 6- or 12-month DAPT group. The major bleeding rate at 1 year was 1.7% with 1 month of DAPT and 2.5% with 6-12 months of DAPT, a nonsignificant difference. Of note, the primary composite endpoint occurred in 5.1% of patients with stable angina who were randomized to 1 month of DAPT, compared with 7.6% with 6 or 12 months of DAPT, a statistically significant difference that translated into a 33% relative risk reduction. In contrast, in patients with unstable angina the primary endpoint occurred in 7.2% of those on 1 month of DAPT and 5.1% with 6 or 12 months of DAPT, a trend that didn't reach significance.

Roughly 75% of patients in the long-DAPT arm were assigned to 12 months of DAPT. That's because the trial began in 2015, before clinical practice guidelines declared 6 months of DAPT to be the recommendation in patients with stable coronary artery disease. The choice of 6 versus 12 months of DAPT in the trial was left up to the patient's physician.

Discussant Roisin Colleran, MBBCh, said the study addresses "an unmet clinical need" for improved antiplatelet regimens following PCI with DES.

Trial's Shortcomings Temper Reaction

"After a period of short DAPT, aspirin monotherapy may be preferable to P2Y12 monotherapy because it's cheaper, with fewer off-target side effects, less variation in treatment response, and fewer contraindications," said Colleran, a cardiologist at Mater Private Hospital, Dublin.

That being said, she shared several reservations about the study. For one, none of the three stents used in the trial is approved by the Food and Drug Administration. The results may not be generalizable to non–East Asian populations. The use of 12 months of DAPT in stable angina patients is out of step with current U.S. and European practice guidelines, which recommend 6 months. And 17% of patients in the 1-month DAPT group were noncompliant with that strategy, meaning they continued on DAPT; had that reverse noncompliance rate been lower, the between-group difference in the primary endpoint might have become statistically significant.

Hong said he thinks the study findings are applicable elsewhere in the world. The 1-month DAPT followed by aspirin monotherapy strategy is attractive in elderly patients, those on oral anticoagulation for atrial fibrillation, individuals who need to undergo noncardiac surgery, and in the large group of stable patients with noncomplex coronary lesions.

"Let's provide these patients with some options," the cardiologist urged.

He is particularly keen on the combination of a polymer-free stent with a drug-elution period of less than 1 month.

"Is polymer perfect? I don't think so. The polymer is a foreign body. It's fantastic, but in 5 or 10 years the polymer may cause irritation and chronic inflammation and a new lesion," Hong said.

Session moderator Wayne B. Batchelor, MD, commented on the battle for stent market share: "It almost appears that we're getting to a ceiling point with coronary interventions whereby at a year we're getting such low ischemic event rates – they're often in the 5%-7% range – that all of these [head-to-head] studies are noninferiority studies, because it's just the only way to do these comparisons nowadays. We can't do 10-, 15-, or 20,000-patient trials. But these noninferiority margins are quite broad."

"Are we stuck just saying: 'All stents are equal,' or are we going to be able to get to the point that we can show that a healing stent is superior?" asked Batchelor, director of interventional cardiology and interventional cardiology research at the Inova Medical Group in Falls Church, Va.

"I think it's going to be very hard to beat the current technology," observed panelist Alexandre Abizaid, MD, PhD, of the Dante Pazzanese Institute of Cardiology in São Paulo. "Even though the polymers are durable, they're biocompatible, and they're hard to beat. It's not going to be easy to show superiority. Maybe in patient subsets."

Hong reported having no financial conflicts of interest regarding the One-Month DAPT trial, funded by DIO, Cardinal Health Korea, and Terumo.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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