AT THE ESC CONGRESS 2017
BARCELONA (FRONTLINE MEDICAL NEWS) – A new model of drug-eluting coronary stent outperformed the reigning benchmark Xience stent in a head-to-head, pivotal comparison with 1,334 patients.
The results “advance a new standard for drug eluting stents,” David E. Kandzari, MD , said at the annual congress of the European Society of Cardiology. The trial tested the Orsiro stent, which features very thin, 60-micron-thick cobalt chromium struts, a bioresorbable polymer, and sirolimus as the antiproliferative drug that’s released during the first 90 days of stent placement.
“To our knowledge, this is the only trial that has demonstrated superiority [of a new stent] to the Xience drug-eluting stent in a large, randomized trial. This is a landmark in interventional cardiology that raises the bar for future comparisons” of drug eluting coronary stents, Dr. Kandzari said in an interview.
The study’s primary endpoint of target lesion failure after 12 months of follow-up – a rate that combined the incidence of cardiovascular death, target-vessel related MI, and ischemia-driven target-lesion revascularization – stood at 6.2% for the 884 patients treated with the Orsiro stent and 9.6% of the 450 randomized to treatment with the Xience stent, which has struts that are 81 microns wide, and a durable polymer that releases everolimus as the antiproliferative drug.
The difference in the primary endpoint was driven primarily by a 3.6% absolute difference in the rate of target-vessel related MIs, a statistically significant difference, plus the Orsiro-treated patients showed numerically smaller rates of cardiac death and ischemia-driven target lesion revascularization, although the between-group differences for each of these two endpoints were not statistically significant. The Orsiro stent also showed a significantly reduced rate of late stent thrombosis, occurring during day 31 through 1 year, a 0.1% rate in the Orsiro-treated patients and a 0.9% rate in those who received Xience stents.
“These are remarkable results,” said Michael Haude, MD , an interventional cardiologist at Lukas Hospital in Neuss, Germany, and a cochair of the session in which Dr. Kandzari gave his report.
These results from the Safety and Effectiveness of the Orsiro Sirolimus Eluting Coronary Stent System in Subjects With Coronary Artery Lesions (BIOFLOW-V) trial will be the centerpiece of an application for U.S. marketing approval for the Orsiro stent, Dr. Kandzari said. The BIOFLOW-V trial enrolled patients at 90 centers in 13 countries including the United States.
Concurrently with his report, the results were published online (Lancet. 2017 Aug 26. doi: 10.1016/S0140-6736[17]32249-3 ).
The potential advantage of a thinner-strut drug eluting stent showed up during the initial treatment phase, with a procedural success rate of 94% using the Orsiro stent and 90% with the Xience stent. This difference in procedural success seemed largely the result of an increased rate of periprocedural MIs, a difference that might be explained by the difference in strut thickness, said Dr. Kandzari, of Piedmont Heart Institute, Atlanta. Based on this success, designers of future drug-eluting stents may focus on thinner-strut models, he suggested.
An additional analysis that Dr. Kandzari reported combined results from two prior randomized comparisons of the Orsiro and Xience stents, creating a pooled analysis with 2,208 patients. This Bayesian analysis calculated a 100% probability of noninferiority of the Orsiro stent compared with the Xience stent, and a 97% probability of superiority. This 97% probability of superiority fell just short of the 97.5% threshold for establishing superiority that Dr. Kandzari and his associates had prespecified for this analysis.
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