MASTER: Positive Results Seen for Bioresorbable-Polymer DES in STEMI

A bioresorbable-polymer DES has demonstrated similar safety at 1 month and better efficacy at 6 months compared with BMS in patients with acute STEMI, researchers reported at TCT 2015. 

For the multicenter, single-blind MASTER trial, César Moris de la Tassa, MD, of Hospital Universitario Central Asturias-Oviedo, in Spain, and colleagues randomized 500 patients with acute STEMI to receive the Ultimaster sirolimus-eluting stent (SES; Terumo; n = 375), which is coated with a bioresorbable polymer, or the Kaname BMS (Terumo; n = 125). The groups had similar demographics, preprocedural medication use, lesion location and procedural characteristics. However, SES-treated patients had a higher number of stents per lesion, stent length and total number of stents per patient.

MASTER had three primary endpoints: safety at 1 month (composite of all-cause death, recurrent MI, unplanned infarct-related artery revascularization, stroke, definite stent thrombosis or major bleeding); efficacy at 6 months (in-stent late loss) and safety/efficacy at 12 months (target vessel failure [TVF]; defined as cardiac death or MI not clearly attributable to a non-target vessel and clinically driven target vessel revascularization).

The safety event rate at 1 month was 3.5% with SES and 7.2% with BMS (P = .13).

At 6 months, the efficacy endpoint of in-stent late loss, assessed in an angiographic subset of 103 SES patients and 32 BMS patients, was also met (Figure). In-segment late loss also was lower with SES (0 ± 0.44 mm vs. 0.55 ± 0.68 mm; P < .001). Patients with SES had reduced percent diameter stenosis, both in-stent (15.1 ± 14.9% vs. 42.2 ± 23%) and in-segment (22.2 ± 15.1% vs. 42.9 ± 22.4%), as well as greater mean lumen diameter, both in-stent (2.44 ± 0.54 mm vs. 1.61 ± 0.63 mm) and in-segment (2.2 ± 0.55 mm vs. 1.56 ± 0.56 mm; P < .001 for all).

Data for the third primary endpoint of 12-month TVF are not yet available, Moris de la Tassa said. However, analysis at 6 months indicated superior outcomes for the SES in terms of clinically driven target lesion revascularization (1.9% vs. 5.6%; P = .05), definite or probable stent thrombosis (1.3% vs. 4.8%; P = .03) and the composite of all-cause death, MI and coronary revascularization (7.7% vs. 14.4%; P = .03).

“Ultimaster showed superior efficacy and favorable safety. This means that a bioresorbable polymer could be a valuable feature in STEMI,” Moris de la Tassa said. He stressed, however, that the full 12-month follow-up for TVF is required “to confirm this hypothesis.”

The MASTER study was conducted at 14 centers in Brazil, Italy, Macedonia, Serbia and Spain. Mean patient age was 60 years in the SES group and 61.5 years in the BMS group, and approximately 80% were men.

Disclosures:

• Moris de la Tassa reports no relevant conflicts of interest.