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BIOSTEMI: SES superior to EES for target lesion failure at 1 year
PARIS — Biodegradable polymer sirolimus-eluting stents were superior to durable polymer everolimus-eluting stents with regard to target lesion failure among patients with STEMI who underwent PCI, according to 1-year results of the BIOSTEMI trial presented at the European Society of Cardiology Congress.
“BIOSTEMI is the first randomized controlled trial powered for superiority comparing two contemporary new-generation drug-eluting stents,” Juan F. Iglesias, MD, FESC, consultant cardiologist at Geneva University Hospitals, said during the presentation. “BIOSTEMI represents the first head-to-head randomized comparison between two new-generation drug-eluting stents in patients with acute STEMI undergoing PCI.”
Researchers designed the BIOSTEMI trial based on exploratory findings from the BIOSCIENCE trial. As Healio previously reported, SES featuring a biodegradable polymer was noninferior to EES in reducing the rate of TLF at 1 year.
Current trial design
In the current trial, researchers compared the efficacy and safety of ultrathin-strut biodegradable polymer SES (Orsiro, Biotronik; 649 patients and 816 lesions; mean age, 62 years; 79% men) with durable polymer EES (Xience Xpedition/Alpine, Abbott Vascular; 651 patients and 806 lesions; mean age, 63 years; 73% men) among patients with acute STEMI who were undergoing primary PCI within 24 hours of symptom onset at 10 hospitals in Switzerland. Patients also had at least one acute infarct artery target vessel with at least one coronary artery stenosis in a native coronary artery and a reference vessel diameter between 2.25 mm and 4 mm.
“The Orsiro biodegradable polymer sirolimus-eluting stents combine a cobalt-chromium stent platform with a strut thickness of 60 µm for stent diameters ranging from 2.25 [mm] to 3 mm and 80 µm for stent diameters ranging from 3.5 [mm] to 4 mm with a unique silicon carbide passive coating and a biodegradable poly-L-lactic acid polymer that elutes sirolimus over the course of 12 to 14 weeks and degrades completely after approximately 2 years,” Iglesias said during the presentation. “On the other hand, the Xience durable polymer everolimus-eluting stent also combined a cobalt-chromium stent platform with a strut thickness of 81 µm with a durable polymer-eluting everolimus.”
Patients were followed up at 30 days, 12 months and 24 months. The primary endpoint was TLF at 12 months, defined as a composite of target vessel myocardial reinfarction, cardiac death or clinically indicated target lesion revascularization. Superiority analysis was also performed using Bayesian methods, which incorporated historical information from 407 patients with acute STEMI from the BIOSCIENCE trial. Secondary endpoints included cardiac death, all-cause death, clinically indicated TLR, target vessel myocardial reinfarction, clinically indicated target vessel revascularization, TLF and definite and definite/probable stent thrombosis.
Results at 1 year
The primary composite endpoint occurred in 3.9% of patients assigned SES vs. 5.5% of those assigned EES (difference = –1.6 percentage points; RR = 0.59; 95% Bayesian credibility interval, 0.37-0.94; posterior probability of superiority = 0.986).
“At 1-year follow-up, 98.6% of the posterior distribution of the rate ratio was found below the superiority margin. Therefore, the BIOSTEMI trial met its primary endpoint with a lower risk of target lesion failure among patients treated with biodegradable polymer sirolimus-eluting stents when compared to patients treated with durable polymer everolimus-eluting stents,” Iglesias said during the presentation.
When individual components of the primary endpoint were assessed, the SES and EES groups had similar rates of cardiac death (2.8% vs. 2.9%, respectively; RR = 0.77; 95% Bayesian credibility interval, 0.43-1.4; Bayesian posterior probability = 0.806) and target vessel myocardial reinfarction (0.8% vs. 0.9%, respectively; RR = 0.55; 95% Bayesian credibility interval, 0.19-1.6; Bayesian posterior probability = 0.875). The rate of clinically indicated TLR was numerically lower among patients assigned SES compared with EES (1.4% vs. 2.6%, respectively; RR = 0.55; 95% Bayesian credibility interval, 0.26-1.13; Bayesian posterior probability = 0.949).
With regard to the secondary endpoints, all-cause death occurred in 3.7% of patients in the SES group and 3.4% of those in the EES group (RR = 0.97; 95% Bayesian credibility interval, 0.58-1.62; Bayesian posterior probability = 0.553). The occurrence of TVF was numerically lower in the SES group vs. the EES group (4.5% vs. 6.8%; RR = 0.61; 95% Bayesian credibility interval, 0.41-0.92; Bayesian posterior probability = 0.991).
“This difference was mainly driven by a lower rate of clinically indicated target vessel revascularization among patients treated with biodegradable polymer sirolimus-eluting stents, 1.7%, when compared to patients treated with durable polymer everolimus-eluting stents, [3.5%],” Iglesias said during the presentation.
There was little evidence showing difference between the SES and EES groups for definite stent thrombosis (0.9% vs. 1.2%, respectively; RR = 0.68; 95% Bayesian credibility interval, 0.22-1.89; Bayesian posterior probability = 0.762) and definite/probable stent thrombosis (1.7% vs. 2.2%, respectively; RR = 0.69; 95% Bayesian credibility interval, 0.32-1.69; Bayesian posterior probability = 0.803).
Results of this trial were simultaneously published in The Lancet. In a related editorial, Clemens von Birgelen, MD, PhD, FESC, director of the department of cardiology at Thoraxcentrum Twente and professor of cardiology at the University of Twente in the Netherlands, and Rosaly Anne Buiten, MD, PhD candidate and clinical researcher at Medisch Spectrum Twente in Enschede, the Netherlands, wrote: “Iglesias and colleagues claim that their use of robust historical priors in their Bayesian statistical model appropriately controlled the type I error rate by down-weighting the contribution of historical information from the earlier STEMI subgroup of BIOSCIENCE, in case the historical information was inconsistent with the information collected in the BIOSTEMI trial. Although this might reassure some readers, others will find the chosen approach too novel, unusual or complex to be credible. Additionally, this approach might make it more difficult to obtain answers to some secondary or additional research questions.” – by Darlene Dobkowski
References:
Iglesias JF, et al. Late-Breaking Science in Intervention. Presented at: European Society of Cardiology Congress; Aug. 31-Sept. 4, 2019; Paris.
Iglesias JF, et al. Lancet. 2019;doi:10.1016/S0140-6736(19)31877-X.
von Birgelen C, et al. Lancet. 2019;doi:10.1016/S0140-6736(19)31955-5.
Disclosures: The BIOSTEMI trial was funded by a dedicated research grant from Biotronik. Iglesias reports he is a consultant for Biotronik, Cardinal Health, Medtronic and Terumo; receives honoraria/speakers fees from AstraZeneca, Biotronik, Cardinal Health, Medtronic, Philips Volcano and Terumo; and receives institutional grant/research support from Abbott Vascular, AstraZeneca, Biotronik and Philips Volcano. Please see the study for all other authors’ relevant financial disclosures. Buiten reports no relevant financial disclosures, and von Birgelen reports his institution has received research grants from Abbott Vascular, Biotronik, Boston Scientific and Medtronic.