TRANSFORM-OCT Evaluates Strut Coverage and Neoatherosclerosis in Bioresorbable Versus Durable Polymer DES

November 2, 2016–Results from TRANSFORM-OCT, a prospective, randomized trial that used optical coherence tomography (OCT) to evaluate strut coverage and neoatherosclerosis found that bioresorbable polymer-based everolimus-eluting stents (BP-EESs) are comparable to durable conformable polymer-based zotoralimus-eluting stents (DP-ZESs). The findings were reported at a First Report Investigation at TCT 2016, the 28th annual Transcatheter Cardiovascular Therapeutics scientific symposium in Washington, DC.

The study sought to determine if bioresorbable abluminal coating may counteract in vivo delayed healing and neoatherosclerosis development in current thin-strut drug-eluting stents. The TRANSFORM-OCT trial was designed, promoted, and implemented by Ospedale Papa Giovanni XXIII in Bergamo, Italy, with unrestricted financial support provided by Boston Scientific International. 

Giulio Guagliumi, MD, from Ospedale Papa Giovanni XXIII, reported that this head-to-head in vivo comparison of early and late healing response demonstrated that the Synergy BP-EES (Boston Scientific Corporation) was noninferior at 3 months and similar at 18-month follow-up to the Resolute Integrity DP-ZES (Medtronic plc).

Dr. Guagliumi concluded that TRANSFORM-OCT adds a novel mechanistic dimension to the assessment of new-generation drug-eluting stents, consolidating the understanding that well-designed and biocompatible polymers, regardless of whether they are durable or biodegradable, may favorably affect the long-term vascular response of these stents.

As summarized in the TCT announcement, TRANSFORM-OCT randomized 90 patients with multivessel disease (1:1) to the Synergy BP-EES or to Resolute Integrity DP-ZES. The primary endpoints were maximum length of consecutive frames with uncovered struts at 3 months (powered for noninferiority of BP-EES) and the percentage of patients presenting with frames of neoatherosclerosis at 18 months (powered for superiority of BP-EES) as measured by OCT. 

The 3-month median percentage of covered struts was 79.1% (interquartile range [IQR], 60.4–89.8) for BP-EES and 78.4% (IQR, 62.1–87.8) for DP-ZES (P = .93). The 18-month median percentage of covered struts was 99.4% (IQR, 96.6–100) for BP-EES and 98% (IQR 94.4–99.8) for DP-ZES (P = .14). From 98.9% of all eligible patients at 18 months, the coprimary endpoint of in-stent neoatherosclerosis was 11.6% for BP-EES versus 15.9% in DP-ZES (P = .59), with a low percentage of frames with neoatherosclerosis in both stent types (1.1 ± 3.1 for BP-EES vs 2.5 ± 9.1 for DP-ZES; P = .33).