Biodegradable stent matches gold standard for safety, efficacy

A next-generation biodegradable drug-eluting stent proved noninferior to the standard of care in a randomized clinical trial that imposed minimal exclusion criteria, according to results published online Sept. 1 in The Lancet and simultaneously presented at the European Society of Cardiology meeting in Barcelona.

Thomas Pilgrim, MD, of the Swiss Cardiovascular Center at University Hospital in Bern, Switzerland, and colleagues provided 12-month results of the BIOSCIENCE study. The single-blind noninferiority trial enrolled patients with stable coronary artery disease or acute coronary syndrome with de novo and restenotic lesions in coronary arteries or bypass grafts, with no restrictions on the number of treated lesions, the number of vessels of lesion length.

The trial compared two stent treatments: a novel biodegradable polymer sirolimus-eluting stent with an ultrathin cobalt-chromium platform (Orsiro, Biotronik AG) and a durable polymer everolimus-eluting stent with a thin cobalt-chromium platform (Xience Prime/Xpedition, Abbott Vascular. The primary endpoint was target lesion failure, which was a composite of cardiac death, target vessel MI and clinically indicated target lesion revascularization at 12 months.

Between 2012 and 2013, 1,063 patients with 1,594 lesions received the biodegradable sirolimus-eluting stent and 1,056 patients with 1,545 lesions received the durable polymer everolimus-eluting stent. At 12 months after implantation, the rate of target lesion failure was 6.7 percent in both groups.

In an as-treated analysis the primary endpoint rates were 6.2 percent in the experimental stent group and 6.7 percent in the control stent group. A subgroup analysis of patients with STEMI found a target lesion failure rate of 3.3 percent with the experimental stent and 8.7 percent with the control stent but the BIOSCIENCE researchers cautioned that the result needed to be substantiated in larger studies.

“Our findings document excellent clinical outcomes for both stent types in a patient population with minimal exclusion criteria—a substantial proportion of whom presented with acute coronary syndromes and complex lesion characteristics,” Pilgrim et al wrote.

Nevertheless, patients enrolled in BIOSCIENCE were not representative of highest-risk patients, they pointed out. Also, more than 80 percent of the trial participants adhered to dual antiplatelet therapy. The Orsiro stent may continue to degrade for 24 months, so results may differ in an analysis with a longer-term follow-up.        

Biotronik funded the study.