Elution of everolimus and sirolimus from a biodegradable polymer coated stent inhibits neointimal hyperplasia without inflammation or toxicity

Abstract

Background: Earfy clinical trials with drug eluting stents have suggested limitations including edge restenosis and malaposition. Persistent bio-stable polymer and/or drug may be causal. Biodegradable polymers hold potential advantage if they are metabolized prior to tissue toxicity and deliver drug during the optimal window. Local delivery of active drug from a slowly biodegradable, high molecular weight polylactic acid (PLA) coated stent could lead to inhibition of intimal hyperplasia without impaired healing. Methods: We compared PLA polymer containing 160 or 220 ug of Everolimus(E), 180 ug Sirolimus(S), and bare metal stent. 40 stents were deployed in coronary artehes of 19 pigs with sacrifice at 28 days. Endpoints were assessed by quantitative coronary angiog raphy @CA), histomorphometry, and histology at 28 and 90 days. Results:There was reduction of intimal hyperplasia as assessed by QCA and histomorphometry by both E and S (Table 1). At both 28 and 90 days, there was complete reendothelialization and ho difference in inflammation or fibrin between the bare stent and druglpolymer groups. Conclusion: Everolimus and Sirolimus delivered via stent and thin layer biodegradable polymer are equally effective at inhibition of intimal hyperplasia. At follow-up evaluation. complete healing without toxic or inflammatory reaction was seen. A clinical trial to determine safety and efficacy of the Everolimus coated stent has commenced.