A short, 1-month treatment combining antiplatelet medication and aspirin followed by an aspirin-only regimen was as effective as a 6- to 12-month course of dual treatment at preventing death, myocardial infarction, stroke, bleeding or revascularization,according to late-breaking trial results presented Sunday at the American Heart Association Scientific Sessions 2020 virtual conference.
Myeong-Ki Hong, MD, PhD, of Severance Cardiovascular Hospital, Seoul, South Korea, presented the findings.
Currently, dual antiplatelet therapy (DAPT) is recommended for 6 to 12 months after drug-eluting stent (DES) implantation. However, it is necessary to determine the appropriate minimal duration of DAPT followed by aspirin monotherapy to minimize unnecessarily long DAPT, Hong said.
The One-Month DAPT trial investigators hypothesized that 1 month of DAPT followed by aspirin monotherapy would be noninferior to 6 to 12 months of DAPT in terms of the composite endpoints of cardiovascular events or major bleeding at 1 year after DES implantation.
In the trial, patients who were considered for revascularization with DES were enrolled in 23 centers in South Korea. Between December 2015 and September 2019, 3,020 patients were randomized to receive either 1-month DAPT followed by aspirin monotherapy after receiving BioFreedom, a polymer-free Biolimus A9-coated stent (1-month DAPT group, n=1,507), or 6 to 12 months of DAPT followed by aspirin monotherapy after implantation with BioMatrix (biodegradable-polymer, Biolimus A9-coated) or Ultimaster (biodegradable-polymer, sirolimus-eluting) stents (6-12 months DAPT group, n=1,513).
The primary endpoint was a 1-year composite of cardiac death, nonfatal myocardial infarction, target-vessel revascularization, cerebrovascular accident or major bleeding. The estimated event rate for patients in the 6-12 month DAPT group was 6.2%. A 3% noninferiority margin was prespecified, giving the study 90% power with a one-sided alpha error rate of 2.5% and allowing for at least 10% loss to follow-up, which required a sample size of 3,020 patients. Noninferiority could be declared if the upper limit of the one-sided 97.5% confidence interval (CI) for the difference in primary endpoint incidences between the groups was less than 3%.
Of the 3,020 patients who were randomized, 1,507 were assigned to the 1-month group and 1,513 were assigned to the 6-12 month group.
At baseline, the groups were well-matched. Patients in both groups had a mean age of 67 years, and 69% were men. About 60% of study patients presented with stable angina. About 17% of patients in the 1-month group did not adhere to the DAPT regimen.
A total of 2,969 patients completed 1-year follow-up. An analysis found no significant difference in the number of cardiac events between the two groups: The 1-month group had a 5.9% composite event rate compared to 6.5% in the 6-12 month treatment group. Each component of the primary endpoint, including major bleeding, was not significantly different between the two groups.
The absolute difference between the groups at 1 year was -0.7%, and the upper limit of the one-sided 97.5% CI was 1.33 (hazard ratio [HR], 0.90; 95% CI, 0.68-1.20; p<0.001 for noninferiority, p=0.475 for superiority). The shorter DAPT regimen also met noninferiority under a 1-month landmark analysis (HR, 0.91; 95% CI, 0.66-1.26; absolute difference -0.5%; upper limit of 97.5% CI, 1.31; p<0.001 for noninferiority, p=0.571 for superiority).
Hong noted that the One-Month DAPT study was the first randomized trial to compare 1-year clinical outcomes of 1-month DAPT followed by aspirin monotherapy to the currently recommended 6- to 12-month regimen in patients with coronary artery disease who have received stents.
“It is encouraging to see that 1-month dual antiplatelet therapy, followed by aspirin monotherapy after polymer-free drug-coated stent, is effective and safe in a diverse group of patients with coronary artery disease,” Hong said in a news release announcing the results. “These results also could lead to the suggestion for some patients to discontinue a P2Y12 inhibitor, rather than aspirin, in daily clinical practice, which could result in better patient compliance, lower costs, a lower risk of bleeding and, overall, more convenience for both patients and physicians.”
This study was funded by DIO, Cardinal Health Korea and Terumo Corp. (manufacturer of the Ultimaster stent). Biosensors International manufactures the BioFreedom and BioMatrix stents.