Polymer-free DES Shown Effective in Multiple Trials

SAN FRANCISCO, CALIF.—Results from several trials have suggested similar effectiveness of polymer-free DES when compared with polymer-based DES, and BMS, according to three presenters at TCT 2011.

ISAR-TEST trials

Julinda Mehilli, MD, of the Technische Universitat Munich, presented data on long-term outcomes from three ISAR-TEST trials, which showed polymer-free rapamycin-eluting stents are as effective as the leading permanent polymer-based DES and probably safer over the long term.

The trial results presented involved three generations of microporous DES without permanent polymer.

In the original ISAR-TEST trial (n=400), results showed that there was no statistically significant difference for in-stent late lumen loss for patients given a first-generation polymer-free DES with rapamycin and patients given a polymer-based DES with paclitaxel (see Figure 1).

In ISAR-TEST 4 (n=2,603), results indicated that a second-generation polymer-free DES had a device-related MACE rate at 3 years of 20.1% compared with 20.9% in the permanent polymer DES arm (P=.59). Rates of stent thrombosis also did not differ significantly (P=.32).

Similarly, in ISAR-TEST 5 (n=3,002), a third-generation dual DES and a polymer-based zotarolimus-eluting stent (Resolute, Medtronic) had equivalent device-related MACE rates at 1-year. The dual DES consists of a microporous, thin-strut stainless steel platform coated with a resin-based mix of sirolimus and probucol, and no polymer.

BioFreedom

Results from the prospective, randomized, multicenter BioFreedom trial showed that a polymer-free DES (BioFreedom, Biosensors International) demonstrated non-inferiority in late lumen loss at 12 months when compared with a paclitaxel-eluting stent (Taxus, Boston Scientific), according to the study’s lead investigator, Eberhard Grube, MD, of the University Hospital Bonn, Germany.

The study included patients who were given a standard dose of the polymer-free DES (n=60) and a lower-dose version of the same stent (n=62); the control group (n=60) was given PES.

At 12-month follow-up, in-stent late lumen loss was significantly improved in patients given the standard dose polymer-free DES compared with those who received PES, but not for those treated with the lower-dose version compared with PES (see Figure 2).

VestaSync II

According to Alexandre Abizaid, MD, PhD, of the Instituto Dante Pazzanese de Cardiologia in São Paulo, Brazil, results from the VestaSync II trial indicated that late lumen loss was effectively reduced by a microporous hydroxyapatite polymer-free sirolimus-eluting stent (VestaSync, MIV Therapeutics) when compared with a next-generation cobalt-alloy BMS (VestaCor, MIV Therapeutics).

In-stent late lumen loss was 0.29 mm in the polymer-free SES arm (n=50) vs. 0.74 mm in the BMS control arm (n=25) (P=.03) at 8-month follow up.

Abizaid reported a MACE rate of 6% in the polymer-free group compared with 14% in the control arm.

“Whether this polymer-free DES approach is safer than the first-generation remains unclear,” said Abizaid. “A larger randomized trial with clinical endpoints is warranted.”