Ori Ben-Yehuda, M.D., presenting the findings of the HOST-REDUCE-POLYTECH-ACS study at TCT 2020 that showed durable polymer drug-eluting stents (DES) performed better than the bioresorbable polymer DES that were supposed to replace them with the promise of being safer and lowering overall cardiac event rates.
October 17, 2020 – In a surprise to many, a randomized clinical trial found that drug-eluting stents (DES) with durable polymers are non-inferior to DES with biodegradable polymers in patients with acute coronary syndrome (ACS). The 3,400-patient HOST-REDUCE-POLYTECH-ACS trial is the first large-randomized study to compare durable polymer to biodegradable polymer stents, and the findings surprised many experts who thought bioresorbable polymers would easily out-perform the older generation durable polymer stent technology.
Findings were reported at the 2020 Transcatheter Cardiovascular Therapeutics (TCT) Connect virtual meeting.
In the primary outcome measure, biodegradeable polymer stents had a higher rate of significant stenosis at one year compared to durable polymer stents, 6.4 vs. 5.2 percent. Secondary outcome measures for cardiac death, target vessel myocardial infarction and target lesion revascularization (TLR) were also in favor of durable polymers (3.9 vs. 2.6 percent). TLR rates alone were 1.8 vs. 1 percent in favor of durable polymer stents.
Newer drug-eluting stents (DES) have significantly improved outcomes among patients undergoing percutaneous coronary intervention (PCI). However, the polymers used in first-generation DES were blamed as the cause of a chronic inflammatory response that leads to stent-oriented adverse clinical outcomes, such as late-stent thrombosis. Biocompatible durable polymers and biodegradable polymers that dissolve over time were developed to help mitigate this adverse effect.
"There was a sign of high numbers of clinical events in the biodegradable, rather than the durable polymer DES. The message is that the hypothesis that biodegradable stents would be better is not actually correct," explained Ori Ben-Yehuda, M.D., executive director of the CRF Clinical Trials Center, who presented this trial in the press conference at TCT 2020. He also is an associate physician of medicine at the University of California San Diego (UCSD). He said the two groups actually both performed pretty well, but longer term study is needed to see if there is any difference in long-term outcomes, which is where there are cases of late-stent thrombosis in durable polymer patients several years after implant.
"I was a little surprised by these results," explained Robert Yeh, M.D., director of the Richard A. and Susan F. Smith Center for Outcomes Research in Cardiology at the Beth Israel Deaconess Medical Center, and associate professor of medicine at Harvard Medical School. He was on the expert panel at the press conference presentation. He is suspicious of the early separation between the groups with cardiac events and wonders if this early separation is due to peri-procedural issues rather than with the stents. Yeh said earlier trials showed the Osiro stent outperformed the Xience, so it is very surprising to see a group of stents with Osiro not perform at least as well as Xience and like stents in this study, he said.
"My main takeaway from this study is that if it is not showing a harm signal for biodegradable polymer DES, it certainly is not showing a benefit, so the question is what is the place for this line of technologies if at the very least we can't demonstrate a substantial benefit over a durable polymer stents," Yeh said.
"We have even looked out to 10 years [in bioresorbable ploymer stent studies in Europe] because where you really expect to see a difference with the different polymers is late or very late events. But, we could not show an edge for biodegradable polymer DES," explained Robert A. Byrne, MB BCh, Ph.D., director of cardiology, Mater Private Hospital, Dublin and chair of cardiovascular research, Royal College of Surgeons in Ireland, who was another member of the expert panel discussing this trial.
Results Bioresorbable Polyermer DES vs. Durable Polymer DES
The comparison of these two polymer technologies in patients with ACS, who have a heightened risk of thrombosis and delayed vascular healing after PCI, has not been previously examined in a large-scale randomized trial. The aim of the HOST-REDUCE-POLYTECH-ACS trial was to investigate the efficacy and safety of a durable polymer DES versus a biodegradable polymer DES in patients with ACS undergoing PCI. Patients with a culprit lesion in a native coronary artery or a graft vessel with significant stenosis eligible for stent implantation were randomized in a 1:1 fashion to durable polymer or biodegradable polymer DES.
The stents used in the study included the dureable polymer stents Promus Premier, Resolute Onyx, Xience Alpine, DESyne, and the bioresorbable polymer stents Ultimaster, Orsiro, Biomatrix Flex, Noborbi, Synergy and Biomatrix.
The primary endpoint was a patient-oriented composite outcome (POCO), defined as a composite of all-cause death, nonfatal myocardial infarction, stent thrombosis, and any repeat revascularization, at 12 months. The key secondary endpoint was a device-oriented composite endpoint (DOCO), a composite of cardiac death, target vessel myocardial infarction, or target lesion revascularization
In this investigator-initiated, randomized, open-label, multicenter trial, a total of 3,413 ACS patients with 4,713 lesions were enrolled from 35 centers and were randomized to the durable polymer DES group (1,713 patients, 2,367 lesions) or the absorbable polymer DES group (1,700 patients, 2,346 lesions).
The rate of POCO was 5.2% in the durable polymer DES compared to 6.4% in the biodegradable polymer DES group (HR 0.81, 95% CI 0.61-1.08, p=0.146). The rate of DOCO was slightly higher in the biodegradable polymer group (2.6% vs. 3.9% HR 0.67, 95% CI 0.46-0.98, p=0.038).
“In ACS patients who had a significant coronary stenosis and were eligible for stent implantation, durable polymer DES was non-inferior to biodegradable polymer DES, in terms of one-year patient oriented composite outcomes,” said Hyo-Soo Kim, M.D., Ph.D. Kim is director, coronary intervention and transcatheter aortic valve implantation, and professor, Department of Internal Medicine at Seoul National University Hospital. “Regarding the device oriented composite outcome, we observed a sign of higher clinical events in the biodegradable polymer DES. More research is needed to assess the effect of polymer technology on clinical outcomes greater than one-year post PCI.”
The HOST-REDUCE-POLYTECH-ACS trial was sponsored by Seoul National University Hospital and received research funds from Biotronik, Boston Scientific, Daiichi Sankyo, Dio, Qualitech Korea Ltd., and Terumo. Kim reported no disclosures.
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