A Medical Device Daily

At this year's edition of the EuroPCR conference held in Paris, the usual list of heavy hitting medical device companies unveiled a slew of new clinical data designed to bolster use of their devices. Particularly heavy this year was data from various companies' drug-eluting stent (DES) trials.

Ian Meredith, MD, principal investigator of the ENDEAVOR I clinical trial and professor of medicine, Monash Medical Centre (Melbourne, Australia), presented long-term clinical results from the Medtronic (Minneapolis) ENDEAVOR I and ENDEAVOR II trials. Medtronic, which is vying to become the third DES player in the U.S. behind Cordis (Miami Lakes, Florida), a Johnson & Johnson (New Brunswick, New Jersey) unit, and Boston Scientific (Natick, Massachusetts), said that data from the two studies shows that the Endeavor drug-eluting coronary stent is continuing to provide significant and sustained efficacy and safety performance over time, with low rates of repeat procedures and no observations of late stent thrombosis.

“Through the dedicated efforts of clinical investigators around the world, these well-designed and robust clinical trials provide compelling evidence characterizing the long-term safety and efficacy of the Endeavor drug-eluting coronary stent,” said Meredith, who presented three-year data from the 100-patient first-in-man ENDEAVOR I clinical study, and two-year results from the 1,200-patient, double-blind randomized ENDEAVOR II pivotal trial. “The patient follow-up for both trials was excellent at 97%, and the clinical results are impressive, with low rates of restenosis and an excellent safety profile.”

The ENDEAVOR I trial had a three-year target lesion revascularization (TLR) rate of just 3%, which means 97% of the patients who received an Endeavor stent required no further treatment or revascularization at the original treatment site after three years of follow-up. In ENDEAVOR II, 93.5% of the Endeavor patients remain free of repeat procedures after two years, with a TLR rate of only 6.5%.

At 36 months, the combined rate for myocardial infarction, death and TLR – a key clinical measurement called Major Adverse Cardiac Events (MACE) - in the ENDEAVOR I study was 6%, while the 24-month MACE rate for ENDEAVOR II was 10%.

The Endeavor drug-eluting coronary stent received CE mark approval in late July 2005 and is now available in more than 85 countries around the world.

Medtronic filed its first premarket approval (PMA) module with the FDA in October 2005. The company said it remains on track for PMA approval in calendar year 2007.

In other EuroPCR news:

• Boston Scientific reported three-year follow-up data from its TAXUS VI clinical trial. The company said the data demonstrated that the safety and efficacy benefits associated with a moderate-release formulation of the Taxus Express paclitaxel-eluting stent system were maintained at three years.

Analysis of the data was presented by Keith Dawkins, MD, of the Wessex Cardiothoracic Center, Southampton University Hospital (Southampton, UK) and co-principal investigator of the trial.

The randomized, double-blind, controlled study of 448 patients at 44 international sites is designed to assess the TAXUS moderate-release paclitaxel-eluting coronary stent system in reducing restenosis in high-risk patients, including long de novo lesions with overlapping stents, small vessels and diabetics. Lesion size ranged from 18 mm - 40 mm in length and 2.5 mm - 3.75 mm in diameter.

The company said that TAXUS VI is the first randomized, controlled clinical trial to demonstrate durability of drug-eluting stents in complex lesions at three years. Follow-up included 98.2% of the patients enrolled at three years (432 out of 440).

“The three-year data from TAXUS VI demonstrates sustained safety and efficacy of the moderate-release Taxus paclitaxel-eluting stent system in patients with long lesions treated with multiple, overlapping stents,” said Dawkins. “It's reassuring to see that even in the most complex lesions ever studied in a drug-eluting stent trial, moderate-release Taxus stents offer sustained target lesion revascularization benefits over time with no compromise to safety.”

The study's results indicate a continued significant reduction in TLR as compared to the bare-metal stent control group at three years. The study reported a three-year TLR rate of 11.7% (25/213) for the Taxus group, as compared with 21.2% (46/217) for the control group. The rate of patients living free of TLR events was 88.4% at three years for the Taxus group, as compared to 79.1% for the bare-metal stent control group.

“The TAXUS ATLAS trial expands one of the largest DES data collections and extends the consistent clinical outcomes seen in the Taxus clinical program to a new stent platform,” said Mark Turco, MD, director, of the Center for Cardiac and Vascular Research at Washington Adventist Hospital (Takoma Park, Maryland) and the trial's co-principle investigator. “The Taxus Liberté stent provides improved deliverability and conformability and the ATLAS trial results support excellent performance in complex lesions more consistent with evolving clinical practice patterns.”

The TAXUS ATLAS trial is a global, multicenter pivotal study comparing the Liberté stent system to a case-matched control group of patients from the TAXUS IV and TAXUS V de novo studies who received the Express(2) stent system.

The trial met its primary endpoint of nine-month target vessel revascularization (TVR), a measure of the effectiveness of a coronary stent in reducing the need for a repeat procedure. The nine-month TVR rate for the Liberté stent was 8%. The study also reported a TLR rate of 5.7% for the Liberté stent.

The Liberté arm of the trial consisted of more complex lesions compared to the control group. The percent of ACC/AHA B2/C lesions was 75.5% compared to 61.2% in the control arm. Lesion characteristics for the Liberté group showed significant differences (increases) in measures of length, bend, tortuosity and calcification compared to the control group. Even with more complex lesions, the Liberté stent was also associated with significantly shorter procedural times.

• NMT Medical (Boston), an advanced medical technology company that develops implant technologies that allow interventional cardiologists to treat cardiac sources of migraine headaches, stroke and other potential brain attacks, presented preliminary clinical results from its BEST (BioSTAR Evaluation STudy) trial were presented at a late breaking clinical trials session at the meeting.

The multicenter BEST trial is designed to evaluate NMT's new bioabsorbable septal closure technology in subjects with patent foramen ovale (PFO) or atrial septal defect (ASD). The trial is being led by Michael Mullen, MD, interventional cardiologist at Royal Brompton Hospital (London).

Mullen reported on the six-month follow-up period of 57 patients enrolled in the study. At 30 days post-implant with Biostar, complete closure rate was achieved in 88.5% of the study subjects. At six months, the complete closure rate increased to 96.4%. No major safety issues were observed.

The average procedure time to close the septal defect with the device was about 40 minutes.

Biostar is NMT's first implant in a series of new, advanced septal closure technologies designed to provide a bioabsorbable option for patients with heart defects like PFO. It incorporates a collagen matrix on the proven Starflex alloy framework. Over time, 90%-95% of the implant is absorbed and replaced with the patient's native tissue providing a more natural, biological closure.

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