TCT: Xience performs much better than Taxus, except in diabetics

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SAN FRANCISCO—Abbott’s Xience V stent demonstrates enhanced safety and efficacy compared with Boston Scientific’s Taxus Express without routine angiographic follow-up, according to the one-year clinical data of SPIRIT IV presented at the late-breaking clinical trials session on Wednesday at the Transcatheter Cardiovascular Therapeutics conference. However, both stents produced positive clinical outcomes.

Gregg W. Stone, MD, director of cardiovascular research at New York-Presbyterian Hospital/Columbia University Medical Center in New York City, who presented the results, said that the safety and efficacy of the Xience V everolimus-eluting stent was previously demonstrated in the first SPIRIT trial, along with SPIRIT II and SPIRIT III randomized trials. However, he noted that these trials were not powered for superiority for clinical endpoints, nor to assess low frequency event rates (death, MI and stent thrombosis), adding that routine angiographic follow up may have adversely affected those results.

Also, no previous trial has been adequately powered to assess a diabetic cohort, according to Stone. This trial enrolled 1,185 diabetic patients, whereas SPIRIT III only had 290 diabetic patients represented in the trial.

In 66 U.S. sites, SPIRIT IV enrolled 3,690 patients—2,500 more patients than SPIRIT III—who were randomized 2:1 to Xience (2,458 patients) or Taxus Express paclitaxel-eluting stent (1,195 patients). Also, the patients in SPIRIT IV were more complex than the participants of the previous trials.

The primary endpoint of target lesion failure through one year was 4.2 percent in the Xience arm and 6.8 percent in the Taxus arm—a statistically significant difference.

Also, Xience V trended similarly well compared with Taxus for the secondary endpoints. For ischemic-driven target lesion revascularization, Xience had a statistically significant decrease compared with Taxus: 2.5 vs. 4.6 percent. However, Stone noted Taxus’ outcomes were also “very good; it’s just that Xience did that much better.”

For cardiac death or target vessel MI, there was a trend toward superiority with a 31 percent reduction for Xience (2.2 vs. 3.2 percent). Stone noted that this is the first trial that has been powered for target lesion revascularization.

Although both stents had very low rates of stent thrombosis, Xience fared better than Taxus up to one year: 0.29 vs. 1.06 percent. This also is a statistically significant difference.

However, the subgroup of diabetics was the only subgroup for which Xience did not show a marked reduction in target lesion revascularization: 6.5 versus 6.9 percent. Also, death among diabetic patients was higher in the Xience arm (1.6 percent) compared with Taxus (0.8 percent). Stone noted that “outcomes in patients with diabetes may still be improved, and should represent an area of focus for future development of novel drugs and enhanced stent design.”

He said that the simultaneous reduction of stent thrombosis, MI and target lesion revascularization with Xience demonstrates that “low, late loss” may be achieved with a drug-eluting stent without sacrificing safety

Stone also said that these data will influence his cath lab decision, as he will use Xience for all his patients who require a drug-eluting stent, besides diabetics.

In his commentary, Jeffrey J. Popma, MD, from Beth Israel Deaconess Medical Center in Boston, noted that the data also inform on trial design, without the necessity of angiographic follow up. He also called SPIRIT IV’s design “superb” and the results “absolutely convincing.”