LEADERS: Biolimus-eluting stent potentially beneficial in patients with STEMI

Use of biodegradable polymer may explain lower adverse event rates in patient subgroup.

Issue: November 2010

Coverage from the Transcatheter Cardiovascular Therapeutics (TCT) 2010 meeting

Three-year results from the LEADERS study suggest potentially noninferior safety and efficacy of a biolimus-eluting stent compared with the use of a sirolimus-eluting stent, although the former may be superior in reducing major adverse CV events in patients with STEMI.

Investigators have previously reported non-inferior major adverse CV event (MACE) rates at 9 months associated with an abluminal biodegradable biolimus A9-eluting stent (BioMatrix Flex, Biosensors) vs. a sirolimus-eluting coronary stent (Cypher Select, Cordis Corp.). That finding was also confirmed at 12 and 24 months, Patrick W. Serruys, MD, PhD, of Erasmus Medical Center, Rotterdam, the Netherlands, said in a presentation.

In the overall patient population enrolled in the prospective, randomized trial, there was no difference in rates of MACE (cardiac death, MI and clinically indicated target vessel revascularization) at 3 years. However, “The Kaplan-Meier curves for MACE continue to diverge, showing lower event rates for the biolimus group,” Serruys said.

Serruys also reported results from a subgroup analysis among STEMI patients showing a lower rate of MACE in patients in the biolimus group compared with the sirolimus group (9.6% vs. 20.7%; P_sup=.01). The explanation for this result is unknown, but the interaction of the biodegradable polymer used in the manufacture of the biolimus stent in the face of long-standing thrombogenesis may be part of the reason, Serruys said.

Further study, Serruys said, is ongoing among patients with STEMI and who are implanted with the biolimus stent.

Outcomes at 3 years

The 3-year results revealed that 812 of the 857 patients initially randomly assigned to the biolimus stent cohort were still being followed, and that the rate of cardiac death in the biolimus stent group was 4.2%. A total of 809 of the 850 patients randomly assigned to the sirolimus stent were still being followed, with a cardiac death rate of 5.2%. The difference did not reach statistical significance.

The rate of cardiac death in either group was not significantly different from the 2-year time point (3.2% in the biolimus group vs. 4.1% in the sirolimus group). The 3-year MI rate was similar between the two groups (7.1% in the biolimus group vs. 7.2% in the sirolimus group). In addition, target vessel revascularization among the study patients was initiated by 3 years in 11.1% of sirolimus-treated patients vs. 9.4% of biolimus-treated patients.

There was no statistically significant difference in MACE rates at any time point in the trial, although Serruys noted that the difference between the two groups may be widening.

Efficacy and safety

No statistically significant difference between the two groups in rates of death, cardiac death, MI, non-Q-wave MI, Q-wave MI or combined cardiac death or MI were reported in a safety and efficacy analysis of markers based on the total randomized population.

Serruys added that the data suggest a trend toward benefit in the biolimus group, and pointed to higher rates of death, cardiac death, Q-wave MI and combined cardiac death or MI, among patients treated with the sirolimus-eluting stent.

Stent thrombosis within the first 30 days was 1.6% in the biolimus group and 1.7% in the sirolimus groups. The 30-day and 1-year rates were 0.4% (biolimus) and 0.5% (sirolimus). The rate of very late stent thrombosis after 1 year among sirolimus-treated patients was 0.9% vs. 0.2% in biolimus-treated patients, although the difference did not attain statistical significance. Serruys also reported no very late stent thrombosis (between years 2 and 3) in the biolimus-treated patients.

Serruys also reported no very late stent thrombosis (occurring between years 2 and 3) among patients in the biolimus-stent group.