November 2, 2016 — Investigators recently unveiled clinical data from the independent BIO-RESORT study, representing the first all-comers analysis to compare the safety and efficacy of biodegradable polymer stents (BP-DES) to the durable polymer Resolute Integrity drug-eluting stent (DP-DES) from Medtronic. At one year, patients with coronary artery disease who were treated with a biodegradable polymer stent showed no clinical benefits over patients treated with Resolute Integrity.
The results were presented during a Late-Breaking Clinical Trial session at the Transcatheter Cardiovascular Therapeutics (TCT) annual meeting, Oct. 29-Nov. 3 in Washington, D.C., and simultaneously published in The Lancet.
BIO-RESORT (TWENTE III) was a large-scale, investigator-initiated, assessor and patient-blinded, multicenter, three-arm trial that compared the safety and efficacy of two novel, very thin-strut biodegradable polymer stents to an established durable polymer stent (Resolute Integrity). Both biodegradable polymer stents have very thin struts but differ in the type, amount, distribution and degradation speed of their respective coating. The Synergy everolimus-eluting platinum chromium stent is the first and only biodegradable polymer drug-eluting stent approved by the FDA for clinical use in the United States and this was its first randomized assessment in an all-comers population. The Orsirio biodegradable polymer sirolimus-eluting cobalt chromium stent has been used clinically outside the United States.
As the authors write in The Lancet manuscript, "Neither of these [biodegradable] stents have [previously] been compared with the new-generation thin-strut durable polymer zotarolimus-eluting stent (Medtronic's Resolute Integrity) — an established device with excellent clinical outcomes."
In the BIO-RESORT study, the primary composite endpoint of target vessel failure at one-year showed no statistically significant difference in outcomes for the Resolute Integrity DP-DES treated group (N=1,173) at 5.4 percent compared to 4.7 percent with the Boston Scientific Synergy BP-DES (N=1,172) arm and 4.7 percent with the Biotronik Orsiro (N=1,169) BP-DES am (difference of 0.7 percent; p=0.45 for Synergy and p=0.46 for Orsiro). The one-year outcomes also found no statistically significant difference in stent thrombosis between Resolute Integrity and the BP-DES groups (difference of 0.1 percent; p=0.77).
"The BIO-RESORT trial demonstrates the continued value of high-quality randomized DES trials in true all-comers, reflecting real-world clinical practice. BIO-RESORT included the greatest proportion of patients with STEMI [ST elevated myocardial infarction] — more than 30 percent — of all previous randomized stent trial in all-comers and one of the greatest proportions of patients with acute coronary syndromes at almost 70 percent," said Prof. Clemens von Birgelen, M.D., Ph.D., co-director of the Department of Cardiology at Thoraxcentrum Twente, professor of cardiology at University of Twente in the Netherlands, principal investigator of the trial and presenter of the data at TCT. "As in our previous randomized study, the DUTCH PEERS trial, patients treated with the Resolute Integrity stent showed low and favorable one-year clinical event rates. The stent was an excellent challenge for the two novel very-thin strut biodegradable polymer drug-eluting stents to compare with, and the results showed no significant difference in the 12-month incidence of the composite primary endpoint. The long-term results of the BIO-RESORT trial will be of great interest, too."
Of the 3,514 patients enrolled and analyzed, 2,449 (69.7%) had acute coronary syndromes, which included 1,073 (30.5%) ST-elevation myocardial infarctions. Twelve-month follow-up was available in 3,490 (99.3%) patients. The primary endpoint was met by 4.7% (55/1,172) of patients assigned to everolimus-eluting stents, 4.7% (55/1,169) assigned to sirolimus-eluting stents and 5.4% (63/1,173) assigned to zotarolimus-eluting stents. The non-inferiority of the everolimus-eluting stent and the sirolimus-eluting stent was confirmed (both: -0.7% absolute risk difference, 95% CI:-2.4–1.1; upper limit of 1-sided 95% CI: 0.8%, Pnon-inferiority<0.0001). Definite stent thrombosis (ARC-defined) occurred in 0.3% (4/1,172), 0.3% (4/1,169) and 0.3% (3/1173) of patients, respectively (logrank-P=0.70 for both main comparisons).
“In patients with coronary artery disease treated with durable polymer-coated drug-eluting stents, the life-long presence of the polymer may delay arterial healing and even cause adverse clinical events,” said von Birgelen. “Biodegradable polymer stents might improve long-term outcomes, but studies with early biodegradable polymer stents that had thick stainless steel struts (120 µm) showed equivocal results. However, very thin-strut (60–81µm) biodegradable polymer stents that have flexible designs and thin, refined coatings are now available.”
The Resolute Integrity DES features Continuous Sinusoid Technology, which provides excellent deliverability and conformability to the vessel wall, according to Medtronic. The durable polymer used with the Resolute Integrity DES, called BioLinx, was specifically designed for DES use. BioLinx is non-inflammatory and non-thrombogenic, which allows for rapid and complete endothelial healing, while minimizing the risk of stent thrombosis. Long-term performance of BioLinx in over 16,000 patients studied in the RESOLUTE clinical program, demonstrated low stent thrombosis in real-world patients through five years, as well as a low risk for stent thrombosis with interruption or discontinuation of dual antiplatelet therapy (DAPT) after one month. The Resolute Integrity stent offers a treatment option with a proven long-term safety and efficacy profile that is yet to be established for new DES designs with biodegradable polymers, according to the company.
The BIO-RESORT study was supported by Boston Scientific, Biotronik and Medtronic.
For more information: www.medtronic.com