Randomized Comparison of Zotarolimus- and Everolimus-Eluting Stents for Coronary Treatment

The use of stents has become common practice in the percutaneous treatment of coronary artery disease. Restenosis affected 20-40% of de novo coronary lesions treated with bare metal stents. Drug-eluting stents (DES) have emerged as the most effective strategy for the prevention of restenosis. The first available DES were the Sirolimus-eluting Cypher and the Paclitaxel-eluting Taxus stent. Although their mid-term efficacy has been well-established, there is an ongoing debate on the potential of an increased incidence of late stent thrombosis, as well as of delayed onset of restenosis or catch-up phenomenon with DES. Recent evidence demonstrates that there might be differences between various DES in terms of safety and efficacy. The differences might be related to the drug, polymer or stent design. Everolimus (SDZ-RAD) and zotarolimus (ABT-578) are new antiproliferative agents that share some common structural and biological properties with sirolimus ("limus-group"). Both drugs bind to the intracellular sirolimus receptor, FK 506-binding protein 12 (FKBP 12). The drug-FKBP12 complex inhibits cell cycle progression via inactivation of the mammalian target of Rapamycin (mTOR) thereby regulating vascular smooth muscle cell migration and proliferation. Preclinical studies showed improved endothelialization and limited chronic inflammation of the everolimus-eluting stent compared with previous drug-eluting stents. Moreover, first randomized clinical trials of everolimus-eluting stents have shown promising results regarding safety, feasibility and efficacy in the suppression of neointimal proliferation. Safety and efficacy of the zotarolimus-eluting Endeavor stent have been investigated in the Endeavor clinical program. In the Endeavor III and IV trials, the Endeavour stent proved inferior to the Cypher and Taxus stents regarding angiographic endpoints. However, rates of target vessel failure were similar in both groups. The Endeavor RESOLUTE stent platform uses a new polymer with potential improvements of drug release compared to the Endeavor stent. The RESOLUTE clinical trial is the first-in man, observational, uncontrolled, non-randomized study evaluating the Endeavor Resolute drug-eluting stent with the new polymer. The trial enrolled a total of 130 patients with native coronary artery lesions. There are no data available comparing the zotarolimus-eluting Endeavor Resolute stent with the everolimus-eluting Xience V stent. Thus the aim of this prospective, randomized study is to compare the efficacy and safety of these two "new generation" drug-eluting stent platforms in a real world population.