SAN FRANCISCO—A stent with a biodegradable coating delivered statistically comparable performance at one year to a drug-releasing stent, researchers reported at a late-breaking clinical trial March 10 at the American College of Cardiology (ACC) scientific session. However, questions from panelists clarified the need for longer-term data to demonstrate the superiority of biolimus-eluting (Xience, Abbott Vascular) compared with everolimus-eluting (Promus, Boston Scientific) stents.
Drug-eluting stents present a double-edged sword. Although they reduce restenosis and target lesion revascularization, the coating slows healing in the stented artery and may trigger an inflammatory response, possibly culminating in late adverse effects.
The biolimus-eluting stent (BES) represents an attempt to solve this clinical dilemma. Its polymer coating dissolves six to nine month after implantation, which may reduce late restenosis or very late stent thrombosis.
The NOBORI Biolimus-Eluting versus Xience/Promus Everolimus-Eluting Stent Trial (NEXT) assigned 3,236 patients to either BES, which was approved in Japan in 2011, or an everolimus-eluting stent (EES), Japan’s top drug-eluting stent, in a randomized open-label study.
The study used an all-comer design and enrolled patients at 98 participating centers in Japan. The primary efficacy endpoint was defined as any target lesion revascularization at one year.
A total of 1,618 patients with 2,116 lesions were randomly assigned to receive BES, and 1,618 patients with 2,053 lesions were assigned to the EES arm. The mean age of the study population was 69.2 years, while 46 percent had diabetes and 51 percent had prior PCI. The two groups of patients were well balanced in terms of baseline clinical, angiographic and procedural characteristics, according to presenter Masahiro Natsuaki, MD, of Kyoto University Graduate School of Medicine’s department of cardiovascular medicine.
Earlier studies had raised concerns about the ability of BES to deliver all intended stents to the target site and achieve the target artery diameter. However, NEXT showed acute device success and patient success were nearly similar and very high in both groups. Device success reached 99.8 percent in the BES cohort and 99.7 percent in the EES group. Patient success was 96.6 percent in the BES group and 96.7 percent in the EES group.
"Our results suggest that BES could be the alternative to EES, a current gold standard second-generation drug-eluting stent,” said Natsuaki, said in a press release.
BES met the goal of non-inferiority to EES in target lesion revascularization at one year, with target lesion revascularization at 4.2 percent for both groups. In addition, the cumulative rates of definite stent thrombosis were low at 0.25 percent in the BES group vs. 0.06 percent in the EES group.
In a substudy of 528 patients, angiographic imaging confirmed similar rates of restenosis in both study arms.
Several panelists questioned the durability of the data, pointing out that differences between the two types of devices may be seen after two or three years. Natsuaki agreed. “Because the polymer will completely disappear one year after stent insertion, at least a three-year timeframe will be needed to demonstrate the potential advantage of BES over other available stents,” he responded. The NEXT research team plans to conduct a three-year follow up.
Follow up will be challenging for several reasons, according to the panel. First, as event rates decrease, future trials will require more and more patients. Second, with such high success rates, it will be very difficult to demonstrate superiority of one device versus another.
“The long-term benefits will be particularly important in this trial,” said Cindy L. Grines, MD, vice president of academic and clinical affairs at Detroit Medical Center Cardiovascular Institute. Despite the “amazing” results of NEXT, the issue of late stent thrombosis remains a significant concern, she added.
The study’s other primary outcome is death or heart attack at three years after stent insertion, with multiple secondary outcome measures for that three-year timeframe. Interim two-year data also will be analyzed.
Grines also noted that NEXT is “not the end of the story” as other similar devices are in development and testing.
“Given the equivalent one-year outcome, long-term clinical data for biodegradable-polymer BES compared with durable-polymer EES will have crucial implications for future