SECURITY: 6-month DAPT performed similar to 12 months with DES implantation

WASHINGTON — The use of a 6-month vs. 12-month regimen of dual antiplatelet therapy yielded comparable outcomes after the implantation of a second-generation drug-eluting stent, suggested findings from the SECURITY trial presented at TCT 2014.

Perspective from Dominick J. Angiolillo, MD, PhD

Lead investigator Antonio Colombo, MD, director of the cardiac catheterization laboratory of MO GVM Centro Cuore Columbus/San Raffaele Hospital in Milan, Italy, presented data from the SECURITY trial, which was concurrently published in the Journal of the American College of Cardiology.

In the prospective, randomized, noninferiority, investigator-driven study, Columbo and colleagues evaluated the utility and safety of prolonged use of DAPT following second-generation DES implantation. The study was conducted at 38 centers in Italy, Spain and the Netherlands with the aim of analyzing the noninferiority of a 6-month DAPT regimen after stent implantation to a year-long duration.

Antonio Colombo

Eligible patients included those with a diagnosis of angina pectoris, unstable angina pectoris and documented silent ischemia, or those with one or more de novo stenoses ≥70% in a native coronary artery. All patients were treated with a second-generation DES and randomly assigned to either a 6-month (n=682) or 12-month (n=717) DAPT regimen.

The primary endpoint was the composite of cardiac death, MI, stroke, definite or probable stent thrombosis, or BARC type 3 or 5 bleeding at 12 months. Secondary endpoints included the following: composite of cardiac mortality, spontaneous MI, stroke, definite or likely stent thrombosis, or BARC 2, 3 or 5 bleeding at 12 and 24 months; MI, urgent target vessel revascularization, all-bleeding events and all-cause mortality at 30 days and 6, 12 and 24 months.

At 1 year, the 6-month DAPT cohort had a 4.5% incidence of the primary endpoint vs. 3.7% in the 12-month group.

At 2 years, the 6- and 12-month cohorts had similar rates of the following endpoints:

Cardiac mortality: 6 month, 0.9% vs. 12 month, 0.8%; HR=1.05; 95% CI, 0.34-3.26; P=.0925;
MI: 6 month, 3.1% vs. 12 month, 2.6%; HR=1.16; 95% CI, 0.62-2.16; P=.636);
Stroke: 6 month, 0.9% vs. 12 month, 0.4%; HR=2.10; 95% CI, 0.52-8.40; P=.636)
Stent thrombosis: 6 months, 0.4% vs. 12 months, 0.4%; HR=1.05; 95% CI, 0.21-5.20; P=.951;
BARC 3 or 5 bleeding: 6 months, 0.7% vs. 12 months, 1.1%; HR=0.69; 95% CI, 0.25-1.96; P=.496.

The two groups also yielded similar rates of the 12-month secondary outcome, with this endpoint occurring in 5.3% of the 6-month group vs. 4% in the 12-month group. Over the subsequent year, the prevalence of the secondary composite endpoints diminished in both groups (6 month, 1.5% vs. 12 month, 2.2%).

Independent predictors of the primary endpoint according to multivariable analysis were age ≥75 years; type of stent used; mean number of stents placed; mean length of stent; and mean stent size.

Determining the most advantageous duration of DAPT in patients undergoing second-generation DES is a controversial topic; previous studies have indicated that 1 year of DAPT may be excessive and potentially unsafe. Discussion moderator Roxana Mehran, MD, of the Zena and Michael A. Weiner Cardiovascular Institute at Mount Sinai School of Medicine, New York, said she found the overall low rates of bleeding to be noteworthy.

Roxana Mehran

“I was surprised that, despite giving 12 vs. 6 months of DAPT, there was no increase in bleeding, and I was surprised by the very low rates of bleeding that were seen,” Mehran, who is Associate Medical Editor of Cardiology Today’s Intervention, said in a press conference.

Panel discussant Stephan Windecker, MD, of the Swiss Cardiovascular Center Bern, Bern, Switzerland, addressed possible explanations for the low incidence of bleeding.

“This is obviously a difficult question to address, but I think overall these results fall into place with the trial evidence we have seen so far comparing 6 vs. 12 months, or even shorter durations such as 3 vs. 12 months of DAPT,” Windecker said at the press conference. “One potential explanation for the lack of significant difference in terms of bleeding complications is that 30% of the patients continued DAPT in the shorter [6-month] range.” – by Jennifer Byrne

For more information:

Colombo A. J Am Coll Cardiol. 2014;doi:10.1016/j.jacc.2014.09.008.

Colombo A. Plenary Session XIX: Late-Breaking Clinical Trials No. 3. Presented at: TCT 2014; Sept. 13-17, 2014; Washington, D.C.

Disclosure: Colombo reports a financial relationship with Direct Flow Medical. Windecker reports receiving grant/research support from Biotronik and St. Jude Medical. Mehran is a consultant for Abbott Laboratories, AstraZeneca, Boston Scientific, Bristol-Myers Squibb, CSL Behring, Covidien, Janssen Pharmaceuticals, Merck and The Medicines Company; is on the scientific advisory boards of Covidien, Janssen Pharmaceuticals and Sanofi Aventis; and has other activities that include, but are not limited to, committee participation and data safety monitoring board membership for Maya Medical, a Covidien company.

Perspective

Dominick J. Angiolillo, MD, PhD

SECURITY was another trial that adds to the studies looking at shorter durations of DAPT in DES-treated patients. It was a noninferiority trial that did not show any differences between 6 months and 12 months of DAPT in terms of the ischemic events, but also there were no trends in bleeding complications.

We do have to keep in mind that there was a considerable number of patients in the 6-month group who actually did continue with DAPT beyond a 6-month timeframe, so the study results were not as clean as one would have liked. Nevertheless, one of the reassuring components of the study is that the ischemic event rates were low, and the stent thrombosis rates were extremely low. So although the study does have some limitations in the way it was actually conducted, it does have added value and provides some confidence in shorter durations of DAPT. Nevertheless, we do await some larger studies that will be presented at American Heart Association Scientific Sessions this year.

Dominick J. Angiolillo, MD, PhD

Cardiology Today’s Intervention Editorial Board member

Disclosures: Angiolillo has received consulting fees/honorarium from Abbott Vascular, AstraZeneca, Bayer, Bristol-Myers Squibb, Daiichi Sankyo, Eli Lilly, Evolva, Merck, PLx Pharma, Sanofi Aventis and The Medicines Company; institutional payments for grants from AstraZeneca, Bristol-Myers Squibb, Daiichi Sankyo, Eli Lilly, Evolva, GlaxoSmithKline, Sanofi-Aventis and The Medicines Company; and has participated in review activities for Johnson & Johnson, St. Jude Medical and Sunovion.