EuroPCR 2021: FUTURE-II hints at promise for Firesorb bioresorbable scaffold

Bo Xu presents at EuroPCR

One-year results of the FUTURE-II study—a randomised trial comparing a thin-strut bioresorbable scaffold to an everolimus-eluting cobalt-chromium stent—could reignite interest in the use of such devices, attendees at EuroPCR 2021 (18–20 May, virtual) heard.

This was according to speaker Bo Xu (Fu Wai Hospital, Beijing, China), who presented findings from FUTURE-II in a late-breaking trial session at the virtual EuroPCR event. The FUTURE-II trial is a randomised trial comparing the thin-strut Firesorb (Microport) bioresorbable scaffold (BRS) to an everolimus-eluting cobalt-chromium stent (EES). The study enrolled 433 patients across 28 Chinese centres between 2017–2019.

Xu said that the Firesorb device could be defined as a second-generation bioresorbable scaffold. The device is a 100‒125μm poly-L-lactic acid (PLLA)-based sirolimus-eluting scaffold, designed to decrease luminal protrusion and improve local haemodynamic profile.

Earlier generations of BRS, according to Xu, were shown to have a high incidence of late adverse events. He put this down to the thickness of the strut (typically 150μm), which he said can result in greater protrusion, delayed re-endothelialisation and unfavourable dismantling during resorption.

FUTURE-II sought to demonstrate the non-inferiority of the Firesorb device versus the EES, with a primary surrogate endpoint of late lumen loss at one year. This is known to be associated with clinical event rates. The major secondary endpoint is one-year proportion of covered struts by optimal coherence tomography (OCT), which was evaluated in a subgroup of 80 patients.

Patients aged between 18‒70 years old, with evidence of myocardial ischaemia and suitable for elective percutaneous coronary intervention (PCI), with a maximum of two de novo lesions in different epicardial coronary vessels and lesion lengths >25m, were deemed eligible for the trial. These patients were randomised in a 1:1 ratio to the Firesorb BRS group (n=215) or to the EES group (n=218).

Xu reported that the trial succeeded in showing the non-inferiority of Firesorb versus EES in terms of one-year angiographic late lumen loss (0.17±0.27 vs. 0.19±0.37 mm, p for non-inferiority <0.0001). Of note implantation technique was almost perfect in both groups, with a high rate of pre-dilatation and post-dilatation, Xu told EuroPCR attendees.

Non-inferiority was also shown in the secondary OCT endpoints, with a similar proportion of covered struts in both groups. Of note, a less incomplete strut apposition was found in the Firesorb group versus EES group at one year, Xu noted.

No difference was found in terms of target lesion failure between groups with very low rate of events (1.9% vs. 3.3%, p=0.37) and no definite or probable device thrombosis.

“The present study proves the midterm safety and efficacy of the thinner-strut Firesorb BRS and might give an opportunity to the comeback of PLLA-based BRS with improved physical and mechanical properties,” said Xu.

After Xu’s presentation, discussants considered the results and their implication for clinical practice. Among them, Alexandra Lansky (Yale University School of Medicine, New Haven, USA), said: “After a long and protracted demise of the BRS programme, I do not think it is an easy task to be the first one out of the gate.

“I hope this will be the revival of the BRS and we will be looking back to this session to say ‘this was the new beginning’.”


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