ABSORB III: Novel Bioresorbable Scaffold as Good as Standard-of-Care DES

A novel bioresorbable scaffold was noninferior to an everolimus-eluting stent (EES) in patients with stable or unstable angina, according to a late-breaking trial presentation at TCT 2015. 

Dean J. Kereiakes, MD, of the Christ Hospital, Cincinnati, Ohio, presented much-anticipated results of the ABSORB III trial, which included 2,008 patients (mean age 63.5 years; 70% men) with evidence of myocardial ischemia treated at 193 centers in Australia and the United States. Patients were randomized to receive the Absorb BVS (Abbott Vascular; n = 1,322; 1,385 lesions) or the cobalt-chromium Xience everolimus-eluting stent (EES; Abbott Vascular; n = 686; 713 lesions). One-year follow-up was available in approximately 99% of each cohort.

Procedural duration was longer and post-dilatation was more likely in the bioresorbable scaffold arm than in controls (P < .001 for both). On quantitative coronary angiography, in-device minimal lumen diameter and acute gain were slightly larger and percent diameter stenosis was smaller in the control arm compared with the bioresorbable-scaffold arm (P < .0001 for all). Device success was 99.3% with Xience and 94.3% with Absorb BVS (P < .0001).

Noninferior, but not superior

One-year target lesion failure (primary endpoint), defined as cardiac death, target-vessel MI or ischemia-driven target lesion revascularization, was only slightly higher with the bioresorbable scaffold vs. the EES, and noninferiority criteria were met (Figure).

However, Absorb did not prove superior to standard of care (P = .16 for superiority). There were no differences in any components of 1-year TLF or angina between the stents, nor were there any differences in device thrombosis in terms of early or late, or definite or probable.

When the 19% of patients with very small vessels (< 2.25 mm) were removed from the analysis, the two devices performed “neck and neck” in terms of both TLF and stent thrombosis, Kereiakes said.

‘Excellence’ needed before routine use

The greatest limitation of ABSORB III, Kereiakes noted, is that all patients had stable disease and “results may therefore not be generalizable to higher-risk patients and more complex disease.”

However, there was never an expectation that Absorb would be superior to standard-of-care DES at 1 year, said TCT Course Director Gregg W. Stone, MD, of NewYork-Presbyterian/Columbia University Medical Center, New York, N.Y. He reminded the audience that ABSORB III was designed as the regulatory approval trial for the FDA.

Furthermore, panelist Ashok Seth, MBBS, MD, DSc, of Fortis Escorts Heart Institute, New Delhi, India, highlighted the fact that all the operators involved in ABSORB III were experts at using Xience but only novices at using the bioresorbable scaffold. 

“Despite optimal Xience implantation and suboptimal Absorb implantation, we have done a good job,” he said. “But when we transfer to real life, we need excellence.”

With regard to the concern over higher cost of the bioresorbable scaffold vs. DES, Daniel Simon, MD, of University Hospitals Case Medical Center, Cleveland, Ohio, said in a press conference that medicine in general allows for higher prices with new technology iterations when there are benefits that coincide with the greater expense, but “we’re just learning what those advantages can be [with bioresorbable scaffolds]. … This is very early on.”

The ABSORB III study results were simultaneously published online in The New England Journal of Medicine.

Disclosures:

• Kereiakes reports receiving consultant/honoraria/speakers bureau fees from Abbott Vascular, Boston Scientific Corporation and SVELTE Medical Systems and speaking about off-label products.
• Seth reports receiving consultant/honoraria/speakers bureau fees from Abbott Vascular, Biosensors, Boston Scientific Corporation, Medtronic and The Medicines Company.
• Simon reports receiving consultant/honoraria/speakers bureau fees from HeartFlow and Medtronic.
• Stone reports relationships with multiple pharmaceutical and device companies.