As clinical trial data have shifted toward favoring second-generation drug-eluting stents (DES), the market has trended in a similar direction. In addition, the overall positive results with most DES have emboldened physicians to use them for more complex disease states, including left main disease—to the dismay and excitement of many.
Is newer better?
One aspect of the recent registries, such as the E-Five Registry, and randomized trials, such as SPIRIT IV and ENDEAVOR IV, is the revelation of longer-term data with larger numbers of patient on the various DES platforms, explains Mark Turco, MD, director of the Center for Cardiac and Vascular Research at the Washington Adventist Hospital in Takoma Park, Md.
The plethora of recent data, including the “encouraging results” with low-frequency, late-occurring events such as stent thrombosis, allows interventionalists to make inferences about potential differences between the various DES, says David E.
Kandzari, MD, director of interventional cardiology research at Scripps Clinic in La Jolla, Calif.
The results show that the crisis from ESC.06, which raised concerns about the correlation between DES and stent thrombosis, has “nearly subsided,” notes David Cox, MD, associate director of the cath lab and director of interventional cardiology research at Lehigh Valley Hospital in Allentown, Pa. “As a result, drug-eluting stents are approaching utilization levels similar to their height of popularity in 2006,” he says.
“Conversely, in the bare-metal stent era, we routinely switched platforms, believing that they all produced similar outcomes,” Kandzari explains. “Now, we are focused on stent safety in addition to efficacy. Ultimately, when choosing a DES, we should focus on the impact a chosen stent will have on the patient over the next 15 years, as opposed to the next 15 minutes of the procedure, regarding deliverability.”
“The exciting results of SPIRIT IV showed that when compared with [Boston Scientific’s] Taxus paclitaxel-eluting stent, [Abbott’s] Xience V everolimus-eluting stent is a very talented platform for safety and efficacy,” says Turco, adding that caveats remain for diabetics as no significant differences in the diabetic population were seen.
The trial results have clearly influenced the U.S. market, where Xience is becoming the preferred stent platform. In fact, the current estimates from Millennium Research Group and Guidepoint Global are that Xience/Promus (the latter of which is sold by
Boston Scientific) holds between 55 and 60 percent of the U.S. market, while Medtronic’s Endeavor maintains about 10 to 15 percent. For first-generation stents, Taxus holds a similar U.S. market share to Endeavor, but it is slipping, and Cordis’ Cypher consumes the remainder of the market.
At TCT.09, the Endeavor zotarolimus-eluting stent platform also showed some strong long-term data, according to Turco. “We are learning that as you get out further along with the Endeavor platform, there is a durability for both safety and efficacy that was not reflected in the early angiographic results,” he says.
Cox speculates that labs which continue to use the first-generation stents may have a contractual relationship with those companies. However, the choice to use first-generation stents is not endangering patients, as these stents also have positive long-term data, Cox says. “Most cath labs will switch over to second-generation products due to the perception of their safety benefits, as well as their unquestionable superior deliverability,” he says.
While Boston Scientific’s market share of conventional DES may slide, it sells the only FDA-approved stents for longer lesions and smaller vessels, so it will continue to dominate those markets.
What’s left? “We need more clinical trial data to assess stenting higher risk patients for off-label usages, such as left main, bifurcation disease, smaller vessels and longer lesions,” Turco says.
Mainly based on consistent data across several trials, the adoption shift continues to move toward the second-generation stents. The COMPARE trial found that Xience has a superior safety and efficacy profile compared to the second-generation Taxus
Liberte paclitaxel-eluting stent in unselected patients undergoing PCI. The difference was attributable to a lower rate of stent thrombosis (less than 1 percent vs. 3 percent), MI (3 vs. 5 percent) and target vessel revascularization (2 vs. 6 percent). Based