Stents that release the drug paclitaxel to treat stenosis more effective than radiation therapy

Insertion of stents that release the drug paclitaxel to treat stenosis within an implanted bare-metal stent in a coronary artery reduces the risk of subsequent re-narrowing within the stent, when compared with treatment using intra-coronary radiation, according to a new study in the March 15 issue of JAMA: The Journal of the American Medical Association.

The study is being released early online to coincide with its presentation at the American College of Cardiology annual conference.

Gregg W. Stone, M.D., of Columbia University Medical Center, New York, and colleagues with the TAXUS V ISR trial compared the use of paclitaxel-releasing stents with vascular brachytherapy (VBT - radiation therapy) in patients with in-stent restenosis (ISR - renarrowing of an artery after treatment) of bare-metal stents.

According to background information in the article, VBT is the only U.S. Food and Drug Administration (FDA)-approved treatment for bare-metal coronary ISR; however, VBT is logistically complex, expensive, and associated with late thrombosis and restenosis. These limitations have resulted in a shift away from VBT for treatment of ISR in daily clinical practice despite the absence of a proven therapeutic alternative. Restenosis occurs in 10 percent to 50 percent or more of patients following implantation of bare-metal stents. Drug-eluting (releasing) stents have been demonstrated to safely reduce restenosis compared with bare-metal stents. Whether drug-eluting stents are safe and effective for treatment of ISR, however, has not been established.

The multicenter randomized trial included 396 patients with in-stent restenosis of a previously implanted bare-metal coronary stent. The study was conducted between June 2003, and July 2004 at 37 North American academic and community-based institutions. Patients were randomly assigned to undergo angioplasty followed by VBT (n = 201) or paclitaxel-releasing stent implantation (n = 195). Clinical and angiographic follow-up at 9 months were scheduled in all patients.

Implantation of paclitaxel-eluting stents compared with VBT significantly reduced the 9-month rate of ischemic target vessel revascularization by 40 percent. The rate of ischemic target lesion revascularization at 9 months was 6.3 percent with the paclitaxel-eluting stent compared with 13.9 percent for VBT, a relative risk reduction of 55 percent. Relative reductions in total target lesion (61 percent) and target vessel (49 percent) revascularization events were higher after treatment with the paclitaxel-eluting stent rather than VBT when only ischemic related events were considered. Paclitaxel-eluting stents reduced the 9-month composite rate of major adverse cardiac events by 43 percent compared with VBT. Patients with paclitaxel-eluting stents had a 53 percent lower rate of angiographic restenosis at 9 months, compared with VBT.

"The results from this trial in concert with other studies, indicate that drug-eluting stents should now be considered the treatment of choice for most patients with ISR of previously implanted bare-metal stents. Paclitaxel-eluting stents significantly reduce clinical and angiographic restenosis and improve event-free survival compared with beta-source intracoronary radiation. For patients with bare-metal stents who develop in-stent restenosis, the availability of drug-eluting stents represents a safe therapy resulting in a high rate of 9-month event-free survival, a reassuring option for an otherwise difficult-to-treat cohort of patients. Further studies are required to demonstrate the long-term safety and durability of this approach," the authors conclude.