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NEXT-GENERATION ZOTAROLIMUS-ELUTING STENT EXHIBITS LOW RATE OF TARGET LESION FAILURE IN U.S. TRIAL
New Polymer Achieves 43 Percent Reduction in Target Lesion Failure versus Historical Control with Minimal Stent Thrombosis at One Year
New Orleans, LA – Expanding on European clinical trials, researchers found that the Resolute® stent achieved a low rate of clinical restenosis (vessel renarrowing) while maintaining low rates of important safety events at 12 months in a U.S. patient population, according to research presented today at the American College of Cardiology’s 60th Annual Scientific Session. ACC.11 is the premier cardiovascular medical meeting, bringing together cardiologists and cardiovascular specialists to further advances in cardiovascular medicine.
The RESOLUTE U.S. trial met its primary endpoint of non-inferiority to the historical control, the FDA-approved Endeavor® stent. It is the first U.S. study to observe the effect of drug elution characteristics on clinical outcomes. Both the Endeavor® stent and the Resolute® stent are designed with the same cobalt chromium platform and use the same drug (zotarolimus), but the Resolute® uses a new biocompatible polymer that allows for an extended drug release across approximately six months (compared to a 14-day release with Endeavor®). This extended release is hypothesized to better prevent vessel renarrowing while still maintaining low stent thrombosis rates.
“The Resolute® drug-eluting stent was shown in this study to deliver strong efficacy without a trade-off in safety through one year of patient follow-up,” said Martin B. Leon, M.D., associate director of the Center for Interventional Vascular Therapy and Professor of Medicine at Columbia University/New York Presbyterian Hospital. “The clinical results achieved with this new device show the important role that biocompatible polymers play in the design of drug-eluting stents.”
Enrolling 1,402 patients across 116 U.S. investigational centers between August 2008 and December 2009, the research team conducted four analyses. The main study included 1,112 patients who received Resolute® stents that were 2.5-3.5 mm in diameter.
The primary endpoint for this group was 12-month target lesion failure (TLF; the composite of cardiac death, target-vessel heart attack, and clinically-driven target lesion revascularization). Clinical follow-up was performed at 30 days, six months, nine months, and 12 months; it will continue at 18 months and annually thereafter through five years post-procedure.
The researchers compared the data from this main study group with historical data pulled from clinical trials of the Endeavor® stent. In order to make accurate comparisons, the team used similar inclusion characteristics, data collection methodologies, endpoint definitions, and statistical analyses. They used propensity score method to adjust for baseline covariates.
After conducting this analysis, the research team found that the Resolute® stent’s rate of TLF at 12 months was 3.7 percent, compared with 6.5 percent for the historical control patients who received the Endeavor® stent, meeting the study’s pre-set margin of non-inferiority (rate difference equals -2.8 percent, upper one-sided 95 percent confidence interval -1.3 percent, p <0.001).
After looking at the individual components of the primary endpoint, the team found that the Resolute® stent also had lower rates of target lesion revascularization, cardiac death and target-vessel heart attack, at 2.0 percent, 0.4 percent, and 1.3 percent, respectively (compared to 4.0 percent, 0.8 percent, and 2.4 percent for the historical control Endeavor® patients).
Evaluation of the entire 1,402-person study group (which included patients with one or two lesions who received stents ranging from 2.25 mm to 4.0 mm) also showed strong outcomes for the Resolute® stent, including a 4.7 percent rate of target-lesion failure and a 0.1 percent of definite or probable stent thrombosis. The overall population included 34 percent diabetic patients, the highest to date in any of the Resolute® trials.
“The outcomes achieved in the diabetic group are better than expected and we can postulate that the Resolute’s® prolonged drug elution profile may contribute to these favorable outcomes in this high-risk group,” Leon said.
Although the study was not a randomized trial, the researchers noted that the propensity score method did allow the team to adequately estimate the effect of changing one of the stent’s three components.
The study was funded by Medtronic. Leon serves on the scientific advisory board for Medtronic.
This study will be simultaneously published online in the Journal of the American College of Cardiology (JACC) and will appear in the April 26, 2011, print edition.
Dr. Leon will be available to the media on Monday, April 4 at 12:30 p.m. CDT in Room 338/339.
Dr. Leon will present the study “Clinical Evaluation of the Resolute Zotarolimus-eluting Coronary Stent System in the Treatment of de Novo Lesions in Native Coronary Arteries (The Resolute U.S. Clinical Trial)” on Monday, April 4, at 10:45 a.m. CDT in the Joint Main Tent: La Nouvelle.
The American College of Cardiology (www.cardiosource.org) represents the majority of board certified cardiovascular care professionals through education, research, promotion, development and application of standards and guidelines – and to influence health care policy. ACC.11 is the largest cardiovascular meeting, bringing together cardiologists and cardiovascular specialists to share the newest discoveries in treatment and prevention, while helping the ACC achieve its mission to address and improve issues in cardiovascular medicine.