SAN DIEGO - September 22, 2018 - This first randomized clinical study of a polymer-coated zotarolimus-eluting stent (Resolute Onyx) that utilizes a novel thin-strutted metallic platform allowing for better x-ray visibility was shown to be non-inferior to an ultrathin-strutted bioresorbable polymer-coated sirolimus-eluting stent (Orsiro) that uses a cobalt-chromium strut platform.
Findings of the BIONYX trial were reported today at the 30th annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium. Sponsored by the Cardiovascular Research Foundation (CRF), TCT is the world's premier educational meeting specializing in interventional cardiovascular medicine. The study was also published simultaneously in The Lancet.
"The vast majority of contemporary stents use stent platforms from cobalt-chromium alloy which allows for the creation of fine mesh tubes with satisfactory radial force, but limited x-ray visibility," said Clemens von Birgelen, MD, PhD, an Interventional Cardiologist at Thoraxcentrum Twente and Professor of Interventional Cardiology at the University of Twente in Enschede, The Netherlands. "Sub-optimal radiographic visibility can be challenging in obese patients, when treating bifurcated or calcified coronary lesions, or when carefully assessing stent expansion."
The Resolute Onyx stent was developed in response to the demand for stents with better radiographic visibility which may facilitate the recognition of stents that are not yet well expanded or incompletely apposed to the arterial wall. The stent uses a novel thin strut composite wire stent platform, covered with a zotarolimus-eluting durable polymer coating. The metallic stent platform consists of a composite wire made from a dense platinum-iridium core, which makes the struts radiopaque, and an outer layer of cobalt-chromium alloy. The dense core also allows for a somewhat lower strut thickness. A head-to-head comparison with the Orsiro stent was of interest, as the Orsiro has shown excellent efficacy and safety outcomes in multiple randomized clinical trials, including three large-scale trials in all-comers.
Between October 7, 2015, and December 23, 2016, a total of 2,488 all-comer patients were included in the intention-to-treat analysis. Participants were between 30 and 96 years of age, 594 (23.9%) were women, 1,765 (70.9%) presented with an acute coronary syndrome, and 1,275 (51.2%) were treated for an acute myocardial infarction at the time of study enrollment.
At one-year follow-up, the primary endpoint of target vessel failure was met by 55 (4.5%) of 1,243 patients assigned to Resolute Onyx, and by 58 (4.7%) of 1,245 assigned to Orsiro. Non-inferiority of Resolute Onyx versus Orsiro was established with an absolute risk difference of -0.2% (95% CI -1.9-1.4) and an upper limit of the one-sided 95% CI of 1.1% (pnon-inferiority=0.0005, psuperiority=0.77).
The rates of cardiac death, target vessel-related myocardial infarction, and clinically indicated target vessel revascularization were low and similar in both groups. Definite or probable stent thrombosis occurred in a single patient (0.1%) in the Resolute Onyx group and nine patients (0.7%) in the Orsiro group (HR 0.11 [95% CI 0.01-0.87], p=0.0112).
"Despite the difference in stent strut materials and thicknesses and the dissimilar durable and bioresorbable polymer coatings of the two study stents, the BIONYX study found no advantage for one stent over the other," added von Birgelen. "Treatment with both stents was similarly safe and effective with excellent one-year clinical outcomes in a complex all-comer patient population. The observed very low stent thrombosis rate in Resolute Onyx warrants further clinical investigation."
The BIONYX trial was funded equally by Biotronik and Medtronic. The sponsors had no access to the study database and no role in the study design, data collection, data analysis, or data interpretation. The research department of Thoraxcentrum Twente has received institutional research grants from Abbott Vascular, Biotronik, Boston Scientific, and Medtronic.
Reference: von Birgelen C, Zocca P, Buiten RA, et al. Thin composite wire strut, durable polymer-coated (Resolute Onyx) versus ultrathin cobalt-chromium strut, bioresorbable polymer-coated drug-eluting stents (Orsiro) in allcomers with coronary artery disease (BIONYX): an international, single-blind, randomised non-inferiority trial. Lancet 2018; manuscript in press [published online September 22, 2018]. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)32001-4/fulltext
About CRF and TCT
The Cardiovascular Research Foundation (CRF) is a nonprofit research and educational organization dedicated to helping doctors improve survival and quality of life for people suffering from heart and vascular disease. For over 25 years, CRF has helped pioneer innovations in interventional cardiology and educated doctors on the latest treatments for heart disease.
Transcatheter Cardiovascular Therapeutics (TCT) is the annual scientific symposium of CRF and the world's premier educational meeting specializing in interventional cardiovascular medicine. Now in its 30th year, TCT features major medical research breakthroughs and gathers leading researchers and clinicians from around the world to present and discuss the latest evidence-based research in the field. TCT also includes interactive training where clinicians can gain vital skills to apply immediately to their practices.