A Medical Device Daily

Ian Meredith, MD, of Monash Medical Centre (Melbourne, Australia) presented positive preliminary results at the Transcatheter Cardiovascular Therapeutics (TCT) conference in Washington from Medtronic ’s (Minneapolis) RESOLUTE clinical trial, a first-in-man study evaluating the company’s Endeavor Resolute zotarolimus-eluting stent system.

Medtronic said that four-month angiographic and clinical results reinforce that zotarolimus continues to be a potent drug preventing restenosis, “even in challenging patient populations.”

RESOLUTE enrolled 130 patients at 12 centers in Australia and New Zealand, with a primary endpoint of late lumen loss at nine months and angiographic, intravascular ultrasound (IVUS) and clinical secondary endpoints. Clinical results for 30 days in 130 patients showed a major adverse cardiac event rate of 3.8%, with no target lesion revascularization (TLR) and no stent thrombosis.

In 30 patients with four-month angiographic follow-up, in-stent late loss was 0.12 mm and in-segment late loss was 0.05 mm. Both in-stent and in-segment binary restenosis were zero; IVUS results showed neointimal volume obstruction of 2.2% at four months.

Stent device and lesion success was 100%, meaning success in placing the stents in the proper location with few complications.

“This trial enrolled patients who required smaller, longer stents, and Endeavor RESOLUTE produced initial clinical and angiographic results that show great promise,” said Meredith, principal investigator of RESOLUTE. “By extending the drug delivery to address the delayed healing, often seen in difficult patient populations, zotarolimus exhibits strong potency with low in-stent and in-segment late loss at four months. Also, acute device and procedural success was very high, particularly when the long lesion lengths were considered.”

The company said the new device “leverages the strengths of the Endeavor stent and introduces a new biocompatible polymer called BioLinx. This new polymer is designed to help match the duration of drug delivery with the longer healing duration often experienced by patients with complex medical conditions.

“BioLinx is different than other polymers in that its outer surface is hydrophilic — water loving — which leads to high biocompatibility with the body, while the interior of the polymer is hydrophobic — water fearing — which helps to precisely control the drug release.”

Medtronic noted the possibility that the polymers on some DES devices can produce an inflammatory response, leading to thrombosis and occlusion of the artery, “more pronounced in patients with complex medical conditions.”

In other news from TCT:

• Boston Scientific (Natick, Massachusetts) reported results of several studies.

In the first 12-month follow-up from the TAXUS ATLAS pivotal trial evaluating the Taxus Libert paclitaxel DES demonstrated that the safety and efficacy of the system at nine months were maintained at 12 months in “workhorse” lesions.

While identical inclusion and exclusion criteria were used for both the Libert stent and the Taxus Express stent historical control group, more complex lesions were treated with the Libert stent than with the Express stent.

The study reported a success rate of 97.6% for delivery of the Taxus Liberte DES by direct stenting, and a shorter procedure time for patients assigned to receive intravascular ultrasound during the index procedure.

The study reported a low 12-month overall cardiac death rate of 0.8% for the Libert DES, as compared to 1% in the control group. The study also reported an overall myocardial infarction rate of 4% for the Libert group, as compared to 3.9% for the control.

The overall rate of thrombosis at 12 months for the Libert group was 0.9%, compared to 0.7% for control. The trial reported an overall TVR rate of 9.2% for the Libert group, compared to 8.9% for the control at 12 months.

TAXUS ATLAS was a global, multi-center, single-arm study enrolling 871 patients at 61 sites.

Results also were reported for the TAXUS OLYMPIA registry, supporting the safety and efficacy of the Labret DES in real-world patients. The results included 12-month data from the 529 patients in Phase I of the multi-phased registry and preliminary six-month data from the first 2,066 patients in Phase III. Both Phase I and Phase III patients exhibited a range of lesion and procedural complexity, reflecting “real world” usage.

Population characteristics included a high proportion of diabetics (50% in Phase I, 32% in Phase III), multi-vessel disease (49% in Phase I, 59% in Phase III), small vessels (40% in Phase I and Phase III), and complex lesions (defined as B2/C, 48% in Phase I, 60% in Phase III).

OLYMPIA Phase I 12-month data demonstrated an overall stent-related cardiac event rate of 3.7%, including Myocardial infarction (MI) (1.4%) and stent-related re-intervention of the target vessel (1.9%). Overall cardiac death was 1.5%. Phase III six-month results showed an overall stent-related cardiac event rate of 3%, including MI (0.9%), and reintervention of the target vessel (1.8%). Overall cardiac death was 0.9%.

Phase I reported an overall stent thrombosis rate of 1.7% at 12 months and Phase III results demonstrated a thrombosis rate of 0.5% out to six months. The company noted that stent thrombosis rates for both Phases are “consistent with safety data from other DES registries.”

Phase I of the OLYMPIA registry enrolled 529 patients at 16 sites in seven countries and met its primary endpoint of Libert stent-related cardiac events at 30 days post implant. Phase III will enroll up to 15,000 patients at up to 250 sites in 20 European countries.