Shelley Wood

November 17, 2011

November 11, 2011 (San Francisco, California) — Two experimental drug-eluting stents (DES) seeking to overcome the shortcomings of current market-approved devices have shown positive results in early phase trials presented during the last late-breaking clinical trials session here at TCT 2011.

Dr Ian Meredith

Dr Ian Meredith (Monash Medical Center, Melbourne, Australia) presented results from the first-in-human EVOLVE trial, testing the everolimus-eluting Synergy stent (Boston Scientific), which uses an ultrathin bioabsorbable polymer coating on the abluminal stent surface only, against the market-approved Promus Element (Boston Scientific).

In EVOLVE, patients with relatively simple de novo CAD were randomized to the Promus Element (n=98), a Synergy stent containing a full dose of everolimus (n=94), or a Synergy stent containing a half-dose of everolimus.

At six months, late loss--the primary angiographic end point for the study--was no different between all three stent groups, ranging from a mean of 0.10 mm in the full-dose Synergy group to 0.15 mm in the Promus Element group, although confidence intervals were wide. Rates of target lesion failure at 30 days and six months were low and also no different between groups.

The findings, said Meredith, support the safety and efficacy of the novel abluminal bioabsorbable polymer Synergy everolimus-eluting stent in these low-risk lesions and pave the way for larger studies.

Dr Didier Carrié

NEXT Up

In a second late-breaking trial, Dr Didier Carrié (Hôpital de Rangueil, Toulouse, France) presented results from a prospective, randomized controlled trial comparing the polymer-free Cre8 (Carbostent & Implantable Devices)) sirolimus-eluting stent (n=147) against the paclitaxel-eluting Taxus Liberté stent (n=146) in patients with simple de novo CAD.

The Cre8 stent is polymer-free but employs an abluminal reservoir technology, with specially formulated sirolimus loaded into the reservoirs.

For the study's primary end point, the Cre8 stent had significantly lower late lumen loss at six months--0.14 mm compared with 0.34 mm for the Taxus Liberté--a statistically significant difference. In a morning press conference, Carrié observed that the trial had been powered to demonstrate noninferiority--which it succeeded in doing--but that the difference in late loss seen was actually statistically significant for superiority.

At 12 months, cumulative rates of major adverse cardiac events (cardiac death, MI, all target lesion revascularization) were no different between groups.

"The NEXT study results support the rationale that high-risk patients should benefit from polymer-free DES implantation," Carrié concluded.

Optimism, But Early Days

During the press-conference discussion following the two presentations, several experts hailed the findings as exciting but emphasized that both studies represented a very early first step.

"We have come to the point that we have stents that are so good that it's going to be hard to beat them," Dr Ron Waksman (Washington Hospital Center, DC) warned. "But overall, if you had to choose between two stents, one with a durable polymer for life and one where you don't have durable polymer, and they do behave exactly the same, then we know in what direction we're probably going to want to go."

Likewise, Dr John Hodgson (Geisinger Heart Institute, Danville, PA) observed: "The big picture here, and everyone has been dancing around it, is that the whole reason these stents are being developed is to see whether we can reduce inflammation, potentially reduce the specter of late stent thrombosis, and thereby reduce the need for long-term dual antiplatelet therapy [DAPT]." That important step, however, has not yet been taken. "So these are just the first stages of development, to show that at least [these devices] can stop neointimal hyperplasia. That's step one."

Dr Roxana Mehran (Mount Sinai School of Medicine, New York, NY) agreed: "It's fair to say that the next wave, the third-generation stents, is going to be focused on safety with shorter duration of DAPT. That's where we're going. . . . The challenge is going to be the clinical trial and what size of trial we're going to need to show something that is exciting and different, because the event rates are so low."

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