A comparison of stent strut thickness between the Orsiro stent, pictured, and the market-leading stents on the U.S. and European markets. Vendors have been working toward reducing strut thickness to help improve overall clinical outcomes. Orsiro is now the smallest strut stent available on the market.
February 22, 2019 — The U.S. Food and Drug Administration (FDA) has approved the Biotronik Orsiro drug-eluting stent (DES) system. Orsiro is the first ultrathin, bioresorbable polymer-coated DES to outperform the current clinical standard Abbott Xience DES.
"This was the first time that an alternative drug-eluting stent demonstrated superiority to the Xience stent," said David Kandzari, M.D., Piedmont Heart Institute, Atlanta. He served as the U.S. principal investigator in the stent's BIOFLOW-V FDA pivotal trial. "Orsiro has set a new standard for safety and efficacy clinical endpoints, including statistically lower target lesion revascularization and target vessel myocardial infarction (MI) rates. BIOFLOW-V data are the best clinical outcomes witnessed with modern DES. It was largely thought that efficacy findings were unsurpassable, but Orsiro proves we can further reduce event rates with meaningful innovation."
Kandzari said the stent showed superiority in the composite endpoints in the BIOFLOW-V Trial. He said Orsiro had excellent clinical performance, demonstrating significantly lower rates for target lesion failure (TLF) and target vessel myocardial infarction (MI) at 12 months in comparison to Xience in a large, complex patient population (n=1,344). At two years, treatment with Orsiro further improved event rates in comparison to Xience, including a significant reduction in target lesion revascularization (TLR) and spontaneous MI.
Points of Difference With the Orsiro Stent
The cobalt chromium metal stent uses a bio-absorbable drug-carrier polymer coating. This dissolves after the vessel wall heals and it finishes elution of its sirolimus antiproliferative drug, turning the Orsiro into a bare metal stent after it has had time to endothelialize and become part of the vessel wall. This technology may help reduce the need for long-term dual antiplatelet therapy (DAPT), which has been a request cardiologists have asked for in next-generation stent technologies.
The Orsiro stent also has the thinnest struts of any DES on the U.S. market at 60 microns. By comparison, the Xience is 81 microns, Boston Scientific's Synergy is 74 microns and the Medtronic Resolute Onyx is 81 microns. Vendors have been steadily working toward thinner devices to prevent blood flow disruption inside the vessel, while at the same time maintaining radial strength and preventing strut fractures.
"There is an emerging body of evidence that would support a lower incidence of myocardial infarction and stent thrombosis events with an ultrasound-thin strut stent. These findings are supported in the BIOFLOW-V Trial with a large body of evidence," Kandzari explained.
Two-year Results Show Superiority to Xience
The two-year results from the BIOFLOW-V Trial were presented at the 2018 Transcatheter Cardiovascular Therapeutics (TCT) conference last fall and published in the Journal of the American College of Cardiology. Data show a 37 percent lower TLF rate in favor of Orsiro (7.5 vs. 11.9 percent TLF rate, p-value=0.015), a 47 percent lower ischemia-driven TLR rate, and a 70 percent lower rate of spontaneous MI (landmark analysis 31 days to two years follow-up).
"There was a significant reduction in target vessel revascularization favoring the Orsiro stent and a statistically significant — and clinically meaningful — reduction in the occurrence of late and very late stent thrombosis," Kandzari said.
He explained the two-year data also suggests a lower incidence of very late stent thrombosis events, which Kandzari said is an issue with the current generation of DES. This will be a key area monitored in subsequent follow-up of patients with the Orsiro stent.
Orsiro Stent Details, Specifications
The stent is indicated for use in percutaneous coronary intervention (PCI) procedures. The cobalt chromium metal stent elutes the antiproliferative drug sirolimus via BIOlute, Biotronik's bioabsorbable poly-L-lactide (PLLA) polymer coating. Beneath the bioabsorbable layer is the company's proBIO, a passive amorphous silicon carbide coating on the bare metal surface, designed to reduce nickel ion release. The company said the Orsiro stent system provides ultrathin stent struts without compromising radial strength, and a low crossing profile for easier lesion cross in complex PCI.
The Orsiro is available in 52 sizes, ranging from 2.25 to 4 mm in diameter. It comes in lengths up to 40 mm, the longest now available in the United States.
The strut thickness varies depending on the diameter of the stent. The 2.25 - 3 mm stents are 60 μm (0.0024 in). The 3.5 - 4 mm are 80 μm (0.0031 in).
Orsiro has an FDA indication for improving coronary luminal diameter in patients, including those with diabetes mellitus, with symptomatic heart disease, stable angina, unstable angina, non-ST elevation myocardial infarction, or documented silent ischemia due to atherosclerotic lesions in the native coronary arteries with a reference vessel diameter of 2.25 to 4 mm and lesion length of ≤ 36 mm.
Kandzari said operators who have used the stent extensively outside the U.S. have claimed it is one of the most deliverable stents they have used and it performs well in tortuous vessels.
Orsiro received European CE marking in 2011 and has been used to treat more than 1 million patients worldwide to date, Biotronik said. Orsiro is now commercially available in the U.S.
Overcoming Commoditization in the DES Market
Biotronik hopes the new stent's clinical data showing its outperformance compared to the current market standard-of-care Xience stent will enable the company to move beyond the current commoditization of stents.
Prior to the presentation of the Spirit IV Trial data for the Xience, there was fierce competition in the stent market based on the latest clinical data to show which vendor had built the device with the best clinical outcomes. However, stent technology improved to a point where adverse events only occur in a small number of patients, so to power a trial large enough to show superiority of any device would be extremely expensive. The current generation DES on the U.S. market, including Xience, have comparable outcomes within a couple percentage points of each other, so the market in recent years has become largely based around price rather than clinical data.
"We are realizing the best outcomes we have ever observed with drug-eluting stents on the market today, which is making it incrementally more difficult to demonstrate a potential difference, much less superiority. The introduction of the Xience was breakthrough in many ways in efficacy and safety measures. While it seems it would be difficult to supersed that, it appears that to date in the BIOFLOW-V trial, we have demonstrated superiority across both safety and efficacy measures," Kandzari explained.
"The FDA approval of Orsiro changes the dynamic of what had become a highly commoditized DES market," said Ryan Walters, president at Biotronik Inc. "We designed Orsiro for use even in challenging cases with features that make it unlike any other DES in the world. Hospital administrators now have available a DES that shows improved clinical event rates, and interventionalists can rely on Orsiro's deliverability to treat complex lesions and challenging subgroups to achieve unprecedented patient outcomes."
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1. Kandzari D et al. Ultrathin, bioresorbable polymer sirolimus-eluting stents versus thin, durable polymer everolimus-eluting stents in patients undergoing coronary revascularisation (BIOFLOW V): a randomised trial. The Lancet 390.10105 (2017): 843-1852.
2. David E. Kandzari, Jacques J. Koolen, Gheorghe Doros, et al. Ultrathin Bioresorbable Polymer Sirolimus-Eluting Stents Versus Thin Durable Polymer Everolimus-Eluting Stents. JACC. Volume 72, Issue 25, December 2018. DOI: 10.1016/j.jacc.2018.09.019