BIOSCIENCE: Biodegradable polymer DES noninferior to durable polymer DES in 1-year TLF

BARCELONA, Spain — Sirolimus-eluting stents featuring a biodegradable polymer were noninferior to everolimus-eluting stents in reducing the rate of target lesion failure at 1 year, according to the BIOSCIENCE trial presented here.

The biodegradable polymer sirolimus-eluting stent (SES; Orsiro, Biotronik; n=1,063) includes a cobalt chromium platform with a 60-mcm strut thickness. In the BIOSCIENCE trial, Thomas Pilgrim, MD, with the Swiss Cardiovascular Center, University Hospital, Bern, Switzerland, and colleagues compared the stent to cobalt chromium everolimus-eluting stents (EES; Xience Prime/Xpedition, Abbott Vascular; n=1,056).

The primary endpoint of target lesion failure — defined as a composite of cardiac death, target vessel MI and clinically indicated target lesion revascularization at 1 year — did not differ between both stent platforms (biodegradable polymer SES, 6.7% vs. durable polymer DES, 6.7%; noninferiority P=.0004). Similarly, there were no significant differences in the rate of definite stent thrombosis (biodegradable polymer SES, 0.9% vs. durable polymer EES, 0.4%; rate ratio [RR]=2.26; 95% CI 0.70-7.33; P=.16).

In a stratified analysis of the primary endpoint, outcomes were similar among patients with diabetes, ACS, off-label stent use, renal failure and those of the same gender. However, Pilgrim and colleagues did observe a statistically significant reduction in patients with STEMI in favor of the biodegradable polymer SES arm (RR=0.38; 95% CI, 0.16-0.19; P=.024).

“The observed benefit in the subgroup of patients with STEMI warrants confirmation in appropriately designed studies,” Pilgrim said at a press conference.

In the corresponding study published in the Lancet, Pilgrim and colleagues wrote that the biodegradable polymer SES matched the outcomes of one of the safest and most effective new-generation drug-eluting stents. “This is notable because the durable polymer everolimus-eluting stent reduces the risk of mortality, myocardial infarction, stent thrombosis and repeat revascularization compared with early-generation paclitaxel-eluting stents, and reduces the rate of stent thrombosis compared with early-generation Cypher sirolimus-eluting stents,” they wrote.

The randomized, single blind, noninferiority BIOSCIENCE trial was conducted at nine hospitals in Sweden from February 2012 to May 2013. Researchers randomly assigned patients with chronic stable CAD or ACS who were undergoing PCI to one of the two DES strategies. Researchers used minimal exclusion criteria and defined noninferiority as a margin of 3.5%.

Patients demonstrated a high rate of adherence (80%) to dual antiplatelet therapy for 12 months. Baseline characteristics were well balanced between the two arms in terms of age, gender, CV risk factors and previous revascularization procedures, according to Pilgrim. – by Brian Ellis

For more information:

Pilgrim T. Hot Line III. Heart Failure: Devices and Interventions. the European Society of Cardiology Congress; Aug. 30-Sept. 3, 2014; Barcelona, Spain.

Pilgrim T. Lancet. 2014;doi:10.1016/s0140-6736(14)61038-2.

Disclosure: Pilgrim reports receiving travel expenses from Biotronik.