DAPT STEMI: 6-month DAPT noninferior to 1 year in high-risk patients

Elvin Kedhi

A 6-month duration of dual antiplatelet therapy for patients who underwent PCI for STEMI was noninferior to a 12-month duration of the therapy, according to data presented at TCT 2017.

Perspective from Updesh S. Bedi, MD, FACC, FSCAI

“While longer DAPT reduces the risk of stent thrombosis and thromboembolic events, in general, it is also associated with a higher risk of bleeding, which sometimes can be fatal,” Elvin Kedhi, MD, PhD, head of interventional cardiology and clinical research and innovation at Isala Hartcentrum in Zwolle, the Netherlands, said during a press conference.

Researchers analyzed data from 1,100 patients who enrolled in the study who had STEMI and were undergoing PCI with a zotarolimus-eluting stent (Resolute Integrity, Medtronic). Patients received DAPT for 6 months, and if they were free from events after that time, they were assigned to single antiplatelet therapy (n = 433) or DAPT (n = 437).

Baseline exclusion criteria included the disruption of DAPT less than 6 months after PCI, known bleeding, oral anticoagulation therapy, drug-eluting stent in the left main coronary artery and a history of stent thrombosis.

The primary endpoint was MI, all-cause mortality, stroke, any revascularization and TIMI major bleeding at 18 months after randomization. Major secondary endpoints included individual components of the primary endpoint, MI, all-cause mortality, stent thrombosis, stroke or TIMI major bleeding at 15 months and 18 months after randomization.

Baseline results, including risk factors, the use of P2Y12 inhibitors and procedure data, were all well-balanced. A history of prior CABG and PCI was seen more in the single antiplatelet therapy group vs. the DAPT group.

At 24 months, the primary endpoint was seen in 6.6% of patients in the DAPT and 4.8% in the single antiplatelet therapy group (HR = 0.73; 95% CI, 0.41-1.27; P for noninferiority = .004). There were no differences for the secondary endpoint between the DAPT group (4.3%) and the single antiplatelet therapy group (3.2%; HR = 0.75; 95% CI, 0.37-1.49).

“This trial for the first time showed that in the modern DES era, event-free STEMI patients do not benefit from a prolonged DAPT beyond 6 months as currently recommended and sets the stage for further dedicated research in this important topic,” Kedhi said.

Further research is already underway with the Onyx ONE clinical study, according to the press conference. This randomized study will include 2,000 patients who are undergoing PCI and have a high bleeding risk, and they will be assigned to a DES (Resolute ONYX, Medtronic) or a drug-coated stent (BioFreedom, Biosensors). Both groups will receive 1 month of DAPT.

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“Physicians are the ultimate DAPT decision-makers. Therefore, it’s critical that we invest in providing relevant and clinically meaningful evidence around DAPT duration,” Martin Rothman, MD, vice president of medical affairs for the coronary and structural heart division at Medtronic, said in a press release. “We look forward to continuing this important research with the upcoming enrollment initiation of our Onyx ONE study that will evaluate 1-month DAPT with the Resolute Onyx DES in patients at a high bleeding risk.” – by Darlene Dobkowski
Reference:

Kedhi E, et al. Late-Breaking Clinical Trials 3. Presented at: TCT Scientific Symposium; Oct. 29-Nov. 2, 2017; Denver.

Disclosure: Kedhi reports he received consultant fees/honoraria, travel fees or institutional grants from Abbott, AstraZeneca, Boston Scientific, Medtronic, Meril, OrbusNeich and Pfizer. Rothman is an employee of Medtronic.

Perspective

Updesh S. Bedi, MD, FACC, FSCAI

DAPT STEMI demonstrates that 6 months of dual antiplatelet therapy is noninferior to 12 months of dual antiplatelet therapy for clinical outcomes among patients who underwent primary PCI for STEMI.
In this trial, the researchers aimed to assess the safety and efficacy of 6 months vs. 12 months of DAPT in patients who presented with STEMI and underwent PCI with a second-generation DES.

There were 433 patients randomly assigned DAPT for 6 months and 437 patients randomly assigned DAPT for 12 months. The duration of follow up was 1 year, and patients were predominantly male, 23% of the patients were female.
The primary outcomes analyzed were all-cause mortality, MI, rate of revascularization, stroke and major bleeding at 18 months.
What they found was that the rate of all of the primary outcomes combined was 4.8% for 6-month DAPT vs. 6.6% for 12-month DAPT and it reached significance for noninferiority, although it didn’t reach statistical significance for superiority.

All-cause mortality was also less in the 6-month group, but there was no statistical difference in all-cause mortality, MI and major bleeding. If you just look at the numbers, STEMI major bleeding was 0.2% in the 6-month group vs. 0.5% in the 12-month group, but it didn’t reach statistical significance. MI was exactly the same at 1.8% in both arms.
The decreased duration of dual antiplatelet therapy did not lead to an increased rate of thrombosis. In the 6-month arm, it was 0.7% vs. 0.9% in the 12-month arm, with no significant difference. There was also no statistical significance in target lesion failure, 1.2% vs. 1.8%.
This trial demonstrated that 6-month DAPT is noninferior to 12-month DAPT. The trial was not powered enough to demonstrate superiority.
Currently, the guidelines are that for stable angina, it’s OK to stop DAPT after 6 months, but with ACS, to continue DAPT for 12 months. This trial invokes the thought that we need additional trials in this arena so we can have more robust data. Then maybe it might affect the guidelines.

Updesh S. Bedi, MD, FACC, FSCAI

Assistant Professor, University of Minnesota

Interventional Cardiologist, Regions Hospital, St. Paul, Minnesota

Disclosures: Bedi reports no relevant financial disclosures.