Wait Continues for a Win With Biodegradable-Polymer DES in Patients at High Bleeding Risk: BIO-RESORT

WASHINGTON, DC—One year is not enough time for newer-generation stents with dissolving polymers to demonstrate an edge over permanent-polymer devices, even in the patients expected to benefit the most, new data hint.

Rates of target vessel failure, a composite of cardiac death, target vessel-related MI, or clinically indicated target vessel revascularization, among patients at high risk for bleeding were equivalent among those treated with a biodegradable- or durable-polymer drug-eluting stent, according to an analysis of the BIO-RESORT study.

Lead investigator Clemens von Birgelen, MD, PhD (Thoraxcentrum Twente, Amsterdam, the Netherlands), who presented the results during a late-breaking clinical trial session at CRT 2018, said a clear benefit of contemporary biodegradable-polymer DES over devices with a durable polymer has not yet been shown, but that they suspected an early advantage might be observed in high-risk patient populations.

“It’s unique data, and it would be a pity to not look at it,” von Birgelen told TCTMD. “However, it was completely uncertain if we would be able to see a difference after just 1 year, although we thought it was worthwhile to have a look. We didn’t see a difference after 1 year in the all-comers study, but we thought some signal, or optimistically maybe even a significant difference, might be seen in a high-risk patient population.”

In BIO-RESORT, which was published in the Lancet in 2016, investigators studied the rate of target vessel failure with two very-thin-strut DES with biodegradable polymers—the everolimus-eluting Synergy (Boston Scientific) and the sirolimus-eluting Orsiro (Biotronik) stents—and with the thin-strut zotarolimus-eluting Resolute Integrity (Medtronic) stent with a durable polymer.

Among the 3,514 patients included in the all-comers trial, 29% had a high risk for bleeding, which was assessed using a number of criteria including age older than 75 years, use of oral anticoagulation, use of NSAIDs, previous gastrointestinal bleeding, previous stroke, renal insufficiency, or the presence of anemia or thrombocytopenia.

Of the 1,009 subjects with a high bleeding risk, near-equal numbers were treated with the Synergy, Orsiro, and Resolute Integrity stents. There was no statistically significant difference in any clinical endpoint at 1 year between the three DES arms. When investigators grouped the biodegradable-polymer Synergy and Orsiro stents and compared these outcomes against Resolute Integrity’s, the rate of target vessel failure at 1 year was not significantly different between the two groups (7.3% with durable-polymer DES vs 6.5% with biodegradable polymer DES; P = 0.63).  

Rates of definite or probable stent thrombosis were low and no different between groups (0.6% with durable-polymer DES and 0.5% with biodegradable polymer DES; P = 0.75).  

Alexandre Abizaid, MD (Instituto Dante Pazzanese de Cardiologia, São Paulo, Brazil), one of the panelists during the late-breaking clinical trial sessions, said he was a “little bit frustrated” given that the rationale behind biodegradable-polymer or polymer-free DES is that the devices would be associated with fewer clinical events compared with durable-polymer DES.

In reply, von Birgelen agreed that this was, indeed, the hoped-for promise of these devices. That said, there is a need to be patient, he added, since study follow-up to date is just 1 year. The advantages of biodegradable polymer DES are unlikely to emerge until 5 years have passed, von Birgelen predicted, noting that they plan to continue to track events over the longer term. The 2-year BIO-RESORT results are scheduled for presentation at EuroPCR 2018 in Paris, France.

“The results will be interesting, that I can tell you,” said von Birgelen.