Biodegradable polymer biolimus-eluting stents noninferior to EES, SES

SAN FRANCISCO — Data presented at TCT 2013 indicate that a biolimus-A9-eluting stent with a biodegradable polymer was clinically noninferior to everolimus-eluting and sirolimus-eluting stents, and may improve long-term clinical outcomes for up to 5 years.

Stephan Windecker, MD, of Bern University Hospital, Switzerland, presented analyses on biolimus-A9-eluting stents (BES) compared with sirolimus-eluting stents (Cypher, Cordis Corporation) and bare metal stents, including the LEADERS and COMFORTABLE AMI trials.

In the LEADERS trial, 1,707 CAD patients were randomly selected to receive a biodegradable polymer BES (BioMatrix Flex, Biosensors; n=857) or a durable polymer sirolimus-eluting stent (n=850). The primary endpoint was a composite of cardiac death, MI or clinically-indicated target vessel revascularization.

At 4 years, there was a clinical follow-up rate of over 96%, at which time the risk for major adverse CV events was lower in patients treated with BES than in those treated with a sirolimus-eluting stent (18.7% vs. 22.6%; P=.050). The RR of definite stent thrombosis was 0.62 (P=.09), which was largely attributed to a lower risk for very late definite stent thrombosis between years 1 and 4 in the BES vs. sirolimus-eluting stent group (RR=0.20; P=.004), demonstrating an 80% relative risk reduction.

An analysis of the correlation between MACE and definite stent thrombosis events showed that the benefit in favor of the BES in terms of MACE was principally driven by a lower risk for MACE associated with very late definite stent thrombosis beyond first year follow-up.

BES vs. BMS

In the COMFORTABLE AMI trial, patients with STEMI who underwent primary PCI were assigned a BES with a biodegradable polymer (BioMatrix, Biosensors Europe SA; n=575) or a BMS of otherwise identical design (Gazelle, Biosensors Europe SA; n=582).

At 1 year, MACE occurred in 24 patients (4.3%) receiving BES with a biodegradable polymer and 49 patients (8.7%) receiving BMS (HR=0.49; 95% CI, 0.3-0.8). Researchers reported a lower risk for target vessel-related reinfarction (0.5% vs. 2.7%; HR=0.20; 95% CI, 0.06-0.69) and ischemia-driven target lesion revascularization (1.6% vs. 5.7%; HR=0.28; 95% CI, 0.13-0.59) in patients receiving BES vs. BMS.

Cardiac death rates were not significantly different (BES, 2.9% vs. BMS, 3.5%; P=.53). Stent thrombosis occurred in five patients (0.9%) treated with BES and 12 patients (2.1%; P=.10) treated with BMS.

“The benefit of BES emerged in the very late phase and was mainly driven by a lower risk of MACE associated with very late definite stent thrombosis,” Windecker said. “It appeared from various subgroup analyses that this stent offered particular benefit in complex patient and lesion characteristics, such as STEMI, bifurcation, multivessel disease and high syntax score. This has been confirmed in the COMFORTABLE AMI trial in which patients BES benefitted patients with STEMI, due to lower risks of target vessel MI, TLR and stent thrombosis.”

Nobori stent analysis

In another presentation, Takeshi Kimura, MD, of Kyoto University Graduate School of Medicine, Japan, presented data from a pooled analysis of the COMPARE II and NEXT trials in which the Nobori BES (Terumo) was compared against the Xience and Xience V stents (Abbott Vascular). According to Kimura, the Nobori BES demonstrated equivalent safety and efficacy up to 1 year compared with everolimus-eluting stents.

In the noninferiority COMPARE II trial, 2,707 patients (n=4,025 lesions) who had a life expectancy more than 5 years and a reference vessel diameter of 2 mm to 4 mm were randomly assigned 2:1 to receive a biolimus-eluting biodegradable polymer stent (Nobori, Terumo; n=1,795) or a durable fluoropolymer-based everolimus-eluting stent (Xience V or Prime, Abbott Vascular; or Promus, Boston Scientific; n=912). The primary endpoint was a composite of safety (cardiac death and nonfatal MI) and efficacy (clinically indicated TVR) endpoints at 12 months.

According to researchers, the biolimus-eluting biodegradable polymer stent was noninferior compared with the everolimus-eluting stent regarding the primary endpoint (5.2% vs. 4.8%; P for noninferiority <.0001), which remained unchanged after per-protocol analysis.

In the NEXT trial, 3,235 patients were randomly assigned to receive the Nobori BES (n=1,617) or an EES (n=1,618). According to study results, the BES achieved its primary endpoint of noninferiority in terms of target lesion revascularization at 1 year (4.2% for both groups; P<.0001). Cumulative incidence of definite stent thrombosis was very low and similar between the BES and everolimus-eluting stent groups (0.25% vs. 0.06%; P=.18).

“We are awaiting the extended follow-up of these randomized trials to evaluate the efficacy and long-term safety of bioabsorbable polymer BES compared with biocompatible durable polymer EES,” Kimura said.

For more information:

Kimura T. Synthesis of clinical trials with the Nobori stent.

Windecker S. Synthesis of clinical trials with the BioMatrix stent. Both presented at: TCT 2013; Oct. 27-Nov. 1, 2013; San Francisco.

Disclosure: Windecker reports receiving institutional grant/research support from Abbott Vascular, Biosensors, Biotronik, Boston Scientific, Cordis, Medtronic and St. Jude Medical. Kimura reports serving on the advisory board of Abbott Vascular and Terumo Japan.