Pairing a bioengineered stent with a drug-eluting balloon could solve two problems

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Harry Suryapranata, MD  

The Genous Bio-engineered R stent, which captures a patient’s endothelial progenitor cells to accelerate the natural healing process, has been shown to reduce late and very late thrombosis compared with drug-eluting stents (DES). The Genous stent, however, has not bested its DES counterparts in reducing in-stent restenosis. A trial in development that will use a drug-eluting balloon to dilate the artery, in combination with deployment of the Genous stent, hopes to fill in the gaps.

The DEBORA Trial (Drug-Eluting Balloon Open Randomized Trial in AMI) is a single-center study that will recruit 100 patients, according to principal investigator Harry Suryapranata, MD, director of clinical research in the department of cardiology at Isala Klinieken, the Netherlands, who spoke to Cardiovascular Business News.

“The implications are that we would achieve both objectives: reduce in-stent restenosis with the drug-eluting balloon and promote rapid healing with the bioengineered stent, thereby reducing the rate of thrombosis,” Suryapranata said.

Patients will be randomized to a conventional balloon plus Genous stent (OrbusNeich) or the DIOR paclitaxel-eluting balloon (EuroCor) plus Genous stent. The primary endpoint is late lumen loss at nine months as shown by angiography.

The late loss with the Genous stent is known to be around 0.7 mm to 0.8 mm. The late loss of the drug-eluting balloon is known to be around 0.3 mm. “So, we won’t need more than 100 patients to show whether the drug-eluting balloon is having a significant impact on in-stent restenosis,” Suryapranata said, noting preliminary data should be available in a year.

Initial studies have found the DIOR drug-eluting balloon to be safe and effective, prompting investigators to conclude that it shows promise to reduce the incidence of in-stent restenosis (Catheterization and Cardiovascular Interventions 2008;71:579-720). The PERFETTO observational registry, developed in late 2007, will test the DIOR balloon in bifurcation lesions, in particular, at the level of the side branch when only the main vessel is stented.

Bruno Scheller, MD, et al showed in a small study that the SeQuent Please paclitaxel-eluting balloon (B. Braun Melsungen) significantly reduced in-stent restenosis rates (NEJM 2006:355[20]:2113-2124), while Martin Unverdorben, MD, et al reported at the 2008 American College of Cardiology meeting that the SeQuent Please balloon was superior to the paclitaxel-eluting Taxus stent (Boston Scientific) in terms of late lumen loss at 12 months.

An already proven advantage of the Genous stent is that patients receiving it need only one month of dual-antiplatelet therapy compared to at least one year of dual-antiplatelet therapy for patients receiving DES.

The action of the endothelial progenitor cells being captured by the stent accelerates the healing process and reduces the risk of stent thrombosis. Angiographic studies have shown significant healing takes place with the Genous stent as early as 48 hours post-implantation, Suryapranata said.  

In contrast, DES use drugs to kill progenitor cells in an effort to reduce in-stent restenosis. The trade-off is the increased risk of stent thrombosis because of the delayed re-endothelialization, for which patients are advised to stay on a longer regimen of dual-antiplatelet therapy.

Indications for the bioengineered stent would be for patients who cannot take dual-antiplatelet therapy for a long duration, such as those scheduled to undergo major surgery, according to Suryapranata.

Researchers also are studying whether the Genous stent would be effective in patients with acute MI, which carries a high thrombus burden. It’s been shown, Suryapranata said, that DES in patients with a high thrombus burden may cause increased events and mortality compared to those with a small thrombus burden.