The Absorb bioresorbable stent made by Abbott (NYSE:ABT) confers a higher risk of serious adverse events at 2 years compared with the company’s Xience drug-eluting stent, according to new data from a study that prompted the FDA to warn physicians on the risk.
But the picture is clouded by new guidelines indicating the proper blood vessel size and implantation technique; some 19% of patients in the 2008-subject trial were implanted in arteries that are now deemed too small for the device. Excluding those patients, the difference between the 2 stents was not statistically significant, according to the study.
“The difference between Absorb and Xience when they’re both implanted in properly-sized vessels with good procedural technique is likely to be quite modest and possibly not clinically important,” said Dr. Stephen Ellis of the Cleveland Clinic, who presented the data from the Absorb III study at ACC 2017.
The results showed that 10.9% of patients in the Absorb arm showed higher rates of target lesion failure (a composite of heart-related death, heart attack related to the treated vessel and revascularization), compared with 7.9% for the Xience cohort. The rate of heart attack was also higher for the Absorb contingent, at 7.3% compared with 4.9% for Xience.
The FDA said it’s investigating the higher adverse event rate for Absorb, which it approved in July 2016 with the proviso that Abbott run a 5-year post-market study of the device.
“The FDA is working with Abbott Vascular, Inc. to conduct additional analyses to better understand the cause(s) of the higher cardiac event and device thrombosis rates in patients treated with [Absorb] compared to the Xience stent. The FDA will continue to monitor the performance of [Absorb] in ongoing clinical studies and in reports submitted to FDA through MedWatch. We will update this communication when additional information or analyses become available,” the federal safety watchdog said.
Ellis said the true benefit of Absorb – “if there is going to be a benefit – will come after it has been fully absorbed.”
“We await long-term outcomes,” he said. “If this device doesn’t produce better long-term outcomes, there’s no point in using it.”
“I think the clinical community should be aware of not only the pros but the cons. I think the obstacles are surmountable. It’s just a question of how much data we need. But I’ll be the first to admit, we don’t know for sure whether or not this device will do better over the long haul. It’s one of these things in medicine where we don’t have all the data,” Ellis told heartwire. “If you look at all patients enrolled in this trial, it’s clear that the patients who got Xience did somewhat better. We’ve already identified, however, the fact that patients with small vessels shouldn’t be treated with Absorb. We’re beginning to accrue more and more information that proper technique benefits patients between 1 year and 2 years.”
Material from Reuters was used in this report.