PROTECT: Still no clear winner in the battle of the stent generations

By Piriya Mahendra, medwireNews Reporter

Three-year rates of stent thrombosis with zotarolimus- and sirolimus-eluting stents are low and comparable, show results of the PROTECT trial.

Rates of other clinical and efficacy endpoints including mortality, myocardial infarction, stroke, bleeding, revascularization, and major adverse cardiac events, were also low and sustained at the 3-year follow up, remarked lead researcher William Wijns (OLV Hospital, Aalst, Belgium) during his study presentation at the European Society of Cardiology (ESC) Congress in Munich, Germany.

Michel Bertrand (Lille Heart Institute, France), a former president of the ESC, commented to medwireNews: "This is an interesting study. The Cypher [sirolimus] stent is first-generation and the zotarolimus stent is new-generation. So we expect it [zotarolimus stent] to have less stent thrombosis and also better results in terms of restenosis. But this is not the case.

"It is surprising that finally there is no major benefit with the new drug-eluting stent."

The PROTECT (Patient Related Outcomes with Endeavor versus Cypher Stenting Trial) included 8709 patients aged 18 years or older who underwent unplanned or emergency procedures in native coronary arteries.

These latest results, simultaneously published online in The Lancet, show that the overall rate of the primary endpoint, which was definite or probable stent thrombosis, did not differ significantly between the two treatment groups at 3 years, at 1.4% with the zotarolimus-eluting stent and 1.8% with the sirolimus-eluting stent.

The rate of stent thrombosis was similar between the two groups after 30 days, but at 31-360 days after revascularization was significantly higher in the 4357 patients implanted with zotarolimus-eluting stents (Endeavor; Medtronic, Minnesota, USA), than the 4352 patients implanted with sirolimus-eluting stents (Cypher; Cordis, New Jersey, USA), at 0.4% versus 0.1%.

By contrast, at 1-3 years, the rate of stent thrombosis was significantly higher among patients who received the sirolimus-eluting stent than those who received the zotarolimus-eluting stent, at 1.1% versus 0.3%.

The discrepancy in stent thrombosis rate with each stent type at these different time points enhances the importance of long-term follow up, noted Wijns in a press conference.

"The rate of stent thrombosis at 3 years with zotarolimus-eluting stents was low as expected," he added. "However, the rate of stent thrombosis with Cypher was lower than expected."

ESC Fellow, Helmut Schuelen (German Heart Center, Munich, Germany), told medwireNews: "It somehow does contradict some data we have from other trials. We do have some trials on newer stents where we did see a low rate of new intimal proliferation, late lumen loss, and restenosis rate as well. Despite the fact that we have this lower rate of late lumen loss, these [newer] stents had a lower rate of stent thrombosis."

Discussant Stephen Windecker (University of Bern, Switzerland) explained that the rationale for the PROTECT study was based on two studies presented at the ESC conference in 2006 that suggested that drug-eluting stents lead to a higher risk for stent thrombosis than bare-metal stents.

"I would like to conclude 6 years on that it was the medical community that recognised the safety issue prior to any industry regulators including the US Food and Drug Administration," he said to laughter from the audience.

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