Byrne, R. A. et al. A polymer-free dual drug-eluting stent in patients with coronary artery disease: a randomized trial vs. polymer-based drug-eluting stents. Eur. Heart J. 30, 923–931 (2009).

A novel, polymer-free, dual-drug-eluting stent (DES) has shown improved or comparable efficacy to two commercially available, permanent polymer stents: the sirolimus-eluting stent (SES; Cypher®, Cordis Corporation, Miami Lakes, FL) and the zotarolimus-eluting stent (ZES; Endeavor®, Medtronic Vascular Inc., Santa Rosa, CA). “We demonstrated that the antirestenotic efficacy of the dual-DES was similar to that of the Cypher stent and superior to that of the Endeavor stent,” comments Robert Byrne, lead study author.

 Antirestenotic performance of the rapamycin+probucol-eluting dual-drug-eluting stent in a rabbit model. Permission obtained from M. Joner.

Durable polymers control the release of active agents from stents; however, the presence of permanent polymer long after its function is useful has been implicated as a potential causal factor in adverse events, such as a persistent inflammatory response at the coronary vessel wall. Byrne and colleagues developed a polymer-free dual (rapamycin and probucol) DES. “Probucol is a potent lipophilic antioxidant that has shown promising antirestenotic efficacy ... [but] has not previously been incorporated in a DES platform,” Byrne explains.

The investigators compared the antirestenoic efficacy of the dual-DES with that of the SES—considered the gold standard in terms of antirestenoic efficacy—and the ZES. Patients undergoing coronary stenting were randomly assigned to treatment with a dual-DES (n = 333), SES (n = 335) or ZES (n = 339). Rates of binary angiographic restenosis and target lesion revascularzation in the dual-DES group (11.0% and 6.8%, respectively) were considerably lower than in the ZES group (19.3% and 13.6%) and comparable with those observed in the SES group (12.0% and 7.2%).

These data demonstrate that a polymer-free DES can achieve comparable efficacy to stent platforms that use polymers. “The potential safety (and maybe long-term efficacy) advantages of a polymer-free DES remains putative and subject to extended follow-up in studies involving larger [numbers of patients],” Byrne concludes.