[TCT2007]SPIRIT III at 1 Year: Xience V　Noninferior to Taxus

Patients with the second-generation drug-eluting　stent had fewer periprocedural MIs and fewer TLR　procedures, at 6 to 12 months.

With 1-year follow-up in the　multicenter randomized　SPIRIT III trial, the Xience V everolimus-eluting stent demonstrated　noninferior rates of target vessel failure　compared with the Taxus paclitaxel-eluting　stent, and patients with the Xience V stent　had fewer TLR procedures than those with　the Taxus stent at 6 to 12 months.
Gregg W. Stone, MD, who presented　the 1-year results of SPIRIT III,　said the rates of death, MI, and stent thrombosis in the trial were not significantly　different between the Xience V(Abbott Laboratories) and Taxus (Boston Scientific) stents.

Larger studies will be required to determine whether there are significant differences between the two devices in low-frequency safety events and in certain subgroups of interest, such as diabetic patients, said Stone, chairman of the Cardiovascular Research Foundation.

In-segment late loss

Stone noted that one previously announced primary endpoint of the SPIRIT III trial, in-segment late loss (LL) at 8 months, was relevant to the current presentation. He said Xience V reduced in-segment LL by 50%, from 0.28 mm with Taxus to 0.14 mm.

At 12 months, investigators achieved 97.4% patient follow-up, including 655 patients with the Xience V DES.
There was a nonsignificant trend toward reduction in TVF with the Xience V stent (8.3% with Xience vs. 10.8% with Taxus, P = .18). TVF as defined in the study included cardiac death, MI, and ischemia-driven TVR.

Stone noted that the endpoint of major adverse cardiac events (MACE) – including cardiac death, MI, and ischemia-driven TLR–is “more specific to the stent itself,” as opposed to TVF. For this endpoint, the difference of 43% between the devices (9.9% with Taxus vs. 5.8% with Xience V) was statistically significant, favoring Xience V (Figure).

A nonsignificant trend favoring the Xience V DES was seen in ischemiadriven TLR at 1 year (5.6% with Taxus vs. 3.3% with Xience, P = .09). There was a nonsignificant trend favoring Taxus in stent thrombosis through 9 months, but the difference disappeared by 1 year.

65 U.S. sites in trial

The SPIRIT III trial included 1,002 patients at 65 U.S. sites with a maximum of 2 lesions of 28 mm or less in length and 2.5 to 3.75 mm in diameter, each in a different epicardial vessel. Patients were randomized 2:1 to receive Xience V or Taxus.

Baseline demographics were well-matched between the two groups, Stone said, although there was a significantly greater incidence of unstable angina in the Taxus group. Lesion location and number of lesions per patient were similar between groups. Compliance with antiplatelet regimens was good in both groups at 6, 9, and 12 months.

Everyday patient data needed

In a critical appraisal of the SPIRIT III trial following Stone’s presentation, Stephen G. Ellis, MD, of the Cleveland Clinic, said that the 1-year safety data for Xience V are comparable with those for other DES.

He said more data will be needed about the performance of the stent in “everyday” patients, including those with diabetes and those with lesions that are “truly small” (reference vessel diameter less than 2.5 mm) or long (greater than 20 mm lesion length).

More data on these types of lesions will be forthcoming from the SPIRIT IV trial, which will include 3,690 patients randomized 2:1 to receive either the Xience V or Taxus DES and will be powered for sequential noninferiority and superiority testing, Ellis said.

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