SAN FRANCISCO – In a head-to-head comparison of two biodegradable-polymer drug-eluting stents, BioMatrix demonstrated noninferiority to Orsiro in Korean patients undergoing percutaneous coronary intervention, according to study results presented Sunday at Transcatheter Cardiovascular Therapeutics 2019.
The disappointing results of bioresorbable scaffolds have led to a re-emerging interest in metal-based drug-eluting stents (DES) that have a biodegradable polymer for the elution of antiproliferative agents, In-Ho Chae, MD, PhD, of Seoul National University Bundang Hospital, said in his slide presentation of BIODEGRADE (Comparison of BIomatrix and Orsiro Drug Eluting Stent in AngioGraphic Result in patients with All-comer Coronary Artery DisEase: A Multicenter, Randomized, Open Label Study).
Chae and colleagues sought to compare the BioMatrix and Orsiro stents. BioMatrix (Biosensors International) is a 316L stainless steel Biolimus A9-eluting stent with a 120-μm strut and abluminal polylactic acid biodegradable polymer that degrades in 9 months. Orsiro (Biotronik) is a cobalt-chromium sirolimus-eluting stent with a passive silicon carbide coating that has a 60- or 80-μm strut and a circumferential poly-L-lactic biodegradable polymer that degrades over 12 to 24 months.
A total of 2341 patients at 25 major hospitals in South Korea were enrolled and randomized, with 1166 patients (1512 lesions) assigned to receive BioMatrix and 1175 (1526 lesions) assigned to receive Orsiro. Patients had an average age of 63.5 years, 71.9% were men, and 59.8% had arterial hypertension. The most common clinical diagnosis to undergo percutaneous coronary intervention in the study was unstable angina (36.5%). There were no significant differences in baseline characteristics between the treatment groups.
The primary endpoint was target lesion failure (TLF), a composite of cardiac death, target vessel-related myocardial infarction and ischemia-driven target lesion revascularization, at 18 months, and the study was designed to prove noninferiority of BioMatrix to Orsiro. The investigators assumed 5% TLF rates in both stents. The noninferiority margin was a one-sided hazard ratio of 1.5.
BioMatrix met the noninferiority primary endpoint (TLF, Orsiro 2.1% vs. BioMatrix 2.9%; hazard ratio, 0.70; 95% confidence interval, 0.42 to 1.18; one-sided noninferiority p < 0.001). There were also no significant differences between groups in the TLF components as well as in ischemia-driven target vessel revascularization, definite stent thrombosis and the patient-oriented composite endpoint.
Chae and colleagues acknowledged several limitations, including a lower-than-expected event rate (expected 5% vs. actual 2.9%), a question of underreporting (trials in East Asian populations tend to have lower reported event rates) and the need for longer-term follow-up, which is planned to continue to 3 years.
The investigators concluded that BioMatrix was noninferior to Orsiro and that both stents showed excellent clinical outcomes in the study. They added that the clinical efficacy of biodegradable-polymer drug-eluting stents may not depend on the stent design, including strut thickness.
The study was sponsored by Seoul National University Bundang Hospital.