A durable polymer-based drug-eluting stent was found to be noninferior to a polymer-free drug-coated stent in patients at a high bleeding risk on 1-month dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI), in a randomized trial.
The Onyx ONE trial compared the polymer-based Resolute Onyx (Medtronic) to the polymer-free BioFreedom (Biosensors), and met its primary outcome, which was a safety composite of death from cardiac causes, myocardial infarction (MI), and stent thrombosis at 1 year.
At that point, a primary outcome event occurred in 169 (17.1%) of Resolute patients and in 164 (16.9%) of those in the BioFreedom group (risk difference, 0.2%; one-sided upper bound 95% CI, 3%; P for noninferiority = .011).
Results were first presented last year at the Transcatheter Cardiovascular Therapeutics (TCT) meeting and reported by theheart.org | Medscape Cardiology at that time.
“These data demonstrate that Resolute Onyx is safe and effective in complex high-bleeding-risk patients who receive 1 month of DAPT,” said study author Stephan Windecker, MD, PhD, Swiss Cardiovascular Center, Bern, Switzerland, at the time of the presentation.
At a press conference held during the TCT meeting, panelist Marco Valgimigli, MD, PhD, University of Bern, said that he doesn’t think the study gives enough information about whether or not 1 month of DAPT is truly optimal for the balance of safety and efficacy in this population.
“However, it answers another question, and that is if the physician decided that 1 month is the way to go, then this study, for the very first time, allows us to know that the Onyx stent is a very viable and reasonable option,” he said.
First Head-to-Head Comparison
In the pivotal LEADERS FREE II trial, which was presented at TCT 2018, a polymer-free umirolimus-coated stent was found safer and more effective than a bare-metal stent in patients at high bleeding risk who received 1 month of DAPT.
However, note the authors, data that directly compare polymer-free drug-coated stents and drug-eluting stents are limited. Polymer-based zotarolimus-eluting stents have previously demonstrated both safety and efficacy in trial populations with minimal exclusion criteria, and a post hoc analysis of trials of the zotarolimus-eluting stent suggested that 1 month of DAPT may be safe after PCI (Eur Heart J. 2014;35:1949-1956).
In the Onyx ONE study, Windecker and colleagues compared current-generation polymer-based drug-eluting stents with polymer-free drug-coated stents in patients at high bleeding risk treated with 1-month DAPT.
Resolute Onyx is a cobalt chromium stent with a core of platinum iridium for increased radiopacity and elutes zotarolimus over 180 days from a durable polymer known as BioLinx. The strut is thin — at 81 μm — in sizes 4.0 and smaller (91 μm in larger — 4.5 mm and 5.0 mm — diameters).
BioFreedom is a polymer- and carrier-free drug-coated stainless steel stent on a micro-structured surface on the abluminal side of the stent. Biolimus is contained without the use of a polymer and released over 28 days. The struts are relatively thick, at 112 μm.
The randomized, single-blind trial involved 1996 patients at a high bleeding risk who were assigned to either Resolute (n = 1003) or BioFreedom (n = 993) stents. After PCI, all patients received 1 month of DAPT, followed by single antiplatelet therapy. Baseline and lesion characteristics were similar in both cohorts.
The main secondary outcome of the study was target-lesion failure, an effectiveness composite of death from cardiac causes, target-vessel myocardial infarction, and clinically indicated target-lesion revascularization.
The discontinuation of DAPT was similar for both cohorts. At 1 month, DAPT had been prescribed for 91.7% of patients in the Resolute group and 93.3% in the BioFreedom group, whereas at 1 year, it had decreased to 5.9% and 8.4%, respectively. Single antiplatelet therapy at 1 year consisted of aspirin for about half the patients in both groups (50.2% and 49.8%), and a P2Y12 inhibitor in 38.8% and 37.1% of the two groups, respectively.
The principal secondary outcome, also powered for noninferiority, was seen in 174 patients (17.6%) in the Resolute group and in 169 (17.4%) in the BioFreedom group (risk difference, 0.2 percentage points; upper boundary of the one-sided 95% CI, 3.0; upper boundary of the one-sided 97.5% CI, 3.5; P = .007 for noninferiority)
A subsequent analysis for superiority, note the authors, did not demonstrate any significant differences between the groups, for either the primary or the principal secondary outcome.
Prespecified secondary outcomes, which included subtypes of MI, were similar in both study groups, and grade 2 to 5 bleeding events occurred in 149 patients (15.1%) in the Resolute group and 133 (13.7%) in the BioFreedom group.
At 1 year, stent thrombosis was also similar, occurring in 13 patients (1.3%) in the Resolute group and 20 (2.1%) in the BioFreedom group.
“This trial adds to the body of evidence from previous trials involving patients at high bleeding risk,” Windecker and colleagues conclude, adding that the “trial thus extends earlier results suggesting that bleeding, more than ischemic risk, should determine clinical decision making regarding the duration of dual antiplatelet therapy.”
The study was funded by Medtronic. Windecker has disclosed institutional research grants from Abbott, Amgen, Bayer, Bristol Myers-Squibb, Boston Scientific, Biotronik, CSL Behring, Edwards Lifesciences, Medtronic, Polares, and Sinomed.
N Engl J Med. Published online February 12, 2020. Abstract