BARCELONA, Spain — "EuroPCR has developed a talent for gathering clinical trials results," William Wijns, MD, president of the European Association for Percutaneous Cardiovascular Interventions, said in an understatement during what turned out to be a marathon session featuring five hours of summary reports on implantable coronary stents.
The clinical trials under way ranged from deep follow-up for well-developed stenting platforms to novel technologies and alternative treatments for clogged vessels.
And as the market for drug-eluting stents, introduced just five years ago, reaches a level of maturity, this year EuroPCR featured a series of meta-data analyses, reports compiling comparable clinical trial data or regional registries that gather results from "all comers," regardless of manufacturer.
This 18th edition of EuroPCR in Barcelona has drawn 11,000 participants from 100 countries for a week-long series of seminars, panel discussions and symposia with 600 speakers. Live cases are being transmitted from 17 centers.
The Tuesday session on late-breaking clinical trials was kicked off by Jean Fajadet, MD, of the Clinique Pasteur Unit de Cardiologie Interventionnelle (Tolouse, France), who delivered four-year data from the ENDEAVOR II clinical trial, a prospective, randomized, multi-center study comparing Medtronic's (Minneapolis) Endeavor drug-eluting stent (DES) to the company's own Driver bare-metal stent.
With 1,197 patients enrolled and a 97% follow-up rate, the trial showed sustained efficacy out to four years with a lower rate of target vessel failure (TVF), a combination of myocardial infarction and cardiac death rates, such as for patients treated with the Endeavor stent.
Fajadet also reported there were no new events requiring target lesion revascularization (TLR) between years three and four.
After delivering his conclusions, Fajadet went out of his way to offer a meta-analysis of his own, which he called a "perspective," by comparing the ENDEAVOR II results with the E-SIRIUS Trial for the Cypher stent from Cordis (Miami Lakes, Florida) and the TAXUS IV for the Taxus Express DES from Boston Scientific (Natick, Massachusetts).
The illustration he offered the 5,000 cardiologists attending the session showed the Endeavor stent reaching a plateau for TLR compared to sharper upward slopes for the competition.
Another challenger to the market dominance currently enjoyed by the Taxus and Cypher stents is the Xience V DES from Abbott Vascular (Santa Clara, California) that is compared head-on to Taxus in the SPIRIT III trial.
The principal investigator for the SPIRIT III trial, Gregg Stone, MD, from Columbia University Medical Center (New York), reported that at two years Xience V demonstrates a 32% reduction in TVF and a 45% reduction in the risk of major adverse cardiac events (MACE), both results being superior to Taxus.
The TVF results are significant in increasing superiority over Taxus from the nine-months results that showed a 20% reduction for Xience V.
Xience V came onto European markets in late 2006 and is currently an investigational device in the U.S. under review by the FDA, for which Abbott said it expects approval in 2Q08.
Gone but not forgotten by Abbott are the ZoMaxx I and II trials, whose lead investigator, William Gray, MD, also from Columbia, reported results from these follow-up studies of patients for the zotarolimus-eluting stent that it scuttled when it acquired the Xience platform (MDD, Oct 4, 2006).
Only two-thirds of the target patient enrollment was achieved by the time Abbott terminated the study in November 2007, and clearly that was a good move as Gray reported the primary endpoint of TVR reduction superior to Taxus was not met among the 1,099 patients.
Building on its dominance over five years, Boston Scientific shared findings culled from a registry of almost 7,500 patients rather than a randomized clinical trial.
There was not a bombshell for Taxus, however in the ARRIVE registries and David Cox, MD, of Lehigh Valley Hospital (Allentown, Pennsylvania) presented two-year results from the pooled data showing low re-intervention rates for patients with diabetes compared to non-diabetics.
Cox took a moment to explain the need to run adjustments to the numbers, a multi-variate analysis, and then reported data mining in the 2,112-patient diabetic subset demonstrated that Taxus "mitigated the adverse effect of diabetes as a risk factor for restenosis and repeat procedures in the patients studied."
The value of the work, he said, is providing insights into diabetic patients who are often at higher risk for adverse events and repeat stenting procedures. Taxus is not specifically indicated for use in patients with diabetes, yet, in the U.S., though the diabetic subset of patients accounts for more than one-fourth of all coronary interventional procedures in that country.
Among the novel technologies for stenting, the top story involved six-month results demonstrating safety and efficacy in the CUSTOM III for Xtent (Menlo Park, California).
A modest 90-patient prospective study to show the Custom NX DES system is feasible for the treatment of patients with coronary artery disease, the patient population is by definition challenging, with two-thirds presenting multiple lesions or extremely long lesions.
The primary endpoint was major adverse cardiac events (MACE) at 30 days, or in other words to show this new method of inserting customizable stent lengths will not kill any of the patients. Xtent reported positive results and added the secondary endpoint at six months has also gone without any deaths.
The Custom NX system allows physicians to customize the length of a stent for a lesion and principal investigator Bernard De Bruyne, MD, from the Onze-Lieve-Vrouw Clinic (Aalst, Belgium), reported placement of a 60 millimeter and 54 mm stent using the modular stent design.
Six mm cobalt chromium scaffold segments are "interdigitalized" so that once the desired length is inserted, the physician can separate the stent, inflate it, and then move on to a new lesion to repeat the procedure without retracting the system from the patient's vascular system.
The average stent length used in the Custom III trial was 30 mm.