Biomedical Engineering Reference
In-Depth Information
US pivotal clinical trial, which is designed to randomize approximately 1,700
patients at up to 75 US sites and 15 international sites. Conor expects the data from
this trial to support its application for US regulatory approval of its CoStar cobalt
chromium paclitaxel-eluting stent. The design of CoStar stent appears to have several
potential advantages as compared to conventional drug eluting stents, including a low
profile for ease of navigation and placement in smaller vessels, the ability to control
the release kinetics of the drug, and the use of a bioresorbable polymer that leaves no
residual polymer or drug on the stent. The COSTAR II trial is a randomized, single-
blind, noninferiority study comparing Conor's CoStar stent with Boston Scientific's
TAXUS
®
Express2 drug-eluting stent in the treatment of de novo lesions in patients
with single or multivessel coronary artery disease. The CoStar stent is loaded with a
dose of 10 mcg of paclitaxel per 17 mm stent using a bioresorbable polymer, a for-
mulation determined to be efficacious during the company's European clinical stud-
ies. Patients will be asymmetrically randomized between CoStar and the control stent
with clinical follow-up at 30 days and 8 months. In addition, a 350-patient subset will
undergo follow-up angiography at 9 months. Enrollment is anticipated to be com-
pleted in approximately 6-9 months. The primary endpoint for the study will be
major adverse cardiac events (MACE) at 8 months, defined as a composite of target
vessel revascularization (TVR), myocardial infarction, and cardiac-related death.
Other endpoints include target lesion revascularization (TLR), binary restenosis, and
in-segment and in-stent late loss as measured by angiography.
Endeavor RESOLUTE Zotarolimus-Eluting Stent System
Current DESs do not meet all the requirements of physicians who deal with the
most challenging clinical cases, such as patients with diabetes. This newest DES
innovation from Medtronic, zotarolimus-eluting stent system, leverages the
strengths of the Endeavor stent and introduces a proprietary, new biocompatible
polymer called BioLinx, which is designed to help match the duration of drug
delivery with the longer healing duration often experienced by patients with com-
plex medical conditions. BioLinx is a noninflammatory polymer blend that mimics
the structure of a cell membrane to maintain biocompatibility. Its outer surface is
hydrophilic, which leads to high biocompatibility with the body, while the interior
of the polymer is hydrophobic, which helps to precisely control the drug release.
As a result, it offers uniform drug dispersion, sustained elution, and the opportunity
for multiple drug platforms.
Positive preliminary results were reported in 2006 from the Medtronic
RESOLUTE clinical trial, a first-in-man study evaluating the new Endeavor
RESOLUTE zotarolimus-eluting stent system. Four-month angiographic and clini-
cal results reinforce that zotarolimus continues to be a very potent drug in prevent-
ing restenosis, even in challenging patient populations. The trial has a primary
endpoint of late lumen loss (in-stent) at 9 months and customary angiographic,
intravascular ultrasound (IVUS) and clinical secondary endpoints. Thirty-day clini-
cal results for 130 patients showed a MACE rate of 3.8%, with zero TLR and no
stent thrombosis. In 30 patients with 4-month angiographic follow-up, in-stent late
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