Meta-analysis: Biodegradable Polymer DES Reduce Stent Thrombosis, TLR at 3 Years

PARIS, France—Biodegradable polymer drug-eluting stents (DES) halve definite stent thrombosis rates at 3 years compared with durable polymer sirolimus-eluting stents and also reduce the need for repeat procedures. The findings, from a pooled analysis of the 3 largest trials comparing the devices, were released at a late-breaking trial session Friday, May 20 at EuroPCR 2011.

Investigator Robert A. Byrne, MD, of Deutsches Herzzentrum München (Munich, Germany), noted that biodegradable polymer DES offer controlled drug release without the need for durable coatings and may improve long-term outcomes. However, “detection of difference in rarely occurring, late adverse events requires the analysis of significantly large patient numbers,” he said.

Three Stronger Than One

Dr. Byrne and colleagues therefore combined individual patient data on 4,052 subjects from 3 previously published randomized controlled trials: ISAR-TEST 3, ISAR-TEST 4, and LEADERS. In all, 2,358 subjects received 1 of 2 different biodegradable polymer DES (n = 1,501 sirolimus-eluting Yukon PC Choice, Translumina, Hechingen, Germany; n = 857 biolimus A9-eluting Biomatrix Flex, Biosensors, Newport Beach, CA) and 1,704 received Cypher sirolimus-eluting stents (Cordis/Johnson & Johnson, Miami Lakes, FL).

“The control group, it's important to note, [was treated with] the first-generation DES [featuring] perhaps the best efficacy and safety record,” Dr. Byrne said.

Three-year follow-up was obtained in each study. Although patient age was slightly higher in the ISAR studies, diabetes prevalence was similar across the trials.

At 3 years, the meta-analysis' primary composite endpoint (cardiac death, MI, and TLR) was reduced in the biodegradable polymer stent group, driven by a difference in TLR. The likelihood of definite stent thrombosis also was 50% lower, although definite/probable stent thrombosis risk was similar between the 2 device types, as was cardiac death/MI risk (table 1). There was no evidence of heterogeneity among trials for any of the endpoints.

Table 1. Biodegradable vs. Durable Polymer DES: Three-Year Outcomes

Landmark analysis found a consistent pattern in definite stent thrombosis rates. Late stent thrombosis (> 30 days) occurred in 0.1% and 0.5% of biodegradable and durable polymer DES patients, respectively, while very late stent thrombosis (> 1 year) occurred in 0.4% and 1.1% (P = 0.02 for both comparisons).

Session co-chair David O. Williams, MD, of Brigham and Women’s Hospital (Boston, MA), asked whether there were any late imaging studies, optical coherence tomography (OCT) or otherwise, that would support the notion that the improved clinical outcomes seen with biodegradable polymer stents might result from better strut coverage.

Dr. Byrne pointed to the OCT substudy of the LEADERS trial (Barlis P. Eur Heart J. 2010;31:165-176), “which showed that for similar degrees of neointimal accumulation in both the biodegradable polymer stent arm and the permanent polymer stent arm, there did seem to be statistically significant reduction in the percentage of uncovered struts with the biodegradable polymer DES. [This] is perhaps a surrogate of improved vascular healing. Of course, longer term follow-up out to 2, 3, 5 years with intravascular imaging studies will shed more light on this, but those results aren't available at the moment.”

Also this week at EuroPCR, Patrick W. Serruys, MD, of Erasmus Medical Center (Rotterdam, the Netherlands), announced the launch of the Global LEADERS trial, which will be the largest randomized head-to-head comparison of 2 DES. The 100-plus site trial is slated to enroll more than 10,000 patients beginning in early 2012 and randomly assign them to receive the Biomatrix Flex or a durable polymer DES. Follow-up is planned for 2 years.

 

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Source:
Byrne R. Biodegradable polymer versus durable polymer drug-eluting stents for patients with coronary artery disease: Three year pooled analysis of individual patient data from the ISAR-TEST 4, LEADERS, and ISAR-TEST 3 randomised trials. Presented at: EuroPCR; May 20, 2011; Paris, France.

 

 

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