Objectives and background: The purpose of this study was to determine the effectiveness and vascular response of a pimecrolimus drug eluting stent and a combination (pimecrolimus + paclitaxel) stent as compared with bare metal controls in the porcine coronary model.
Methods and results: In the first phase of the study, cobalt chromium stents were loaded with an erodible polymer and either a slow release or a fast release formulation of pimecrolimus. Thirty stents (metal, n = 10; pimecrolimus slow, n = 10; pimecrolimus fast, n = 10) were implanted in the coronary arteries of 10 pigs. At 30 days, neointimal proliferation and inflammation were both significantly less in the pimecrolimus fast release group as compared with the bare metal controls. Endothelialization was complete and equal in all three groups of stents. In the second phase of the study, stents were loaded with an erodible polymer with alternating reservoirs of paclitaxel and pimecrolimus. Twenty stents (8 control stents and 12 dual stents) were implanted in the coronary arteries of seven pigs. At 30 days, neointimal proliferation was significantly less in the dual drug group as compared with the bare metal controls. Endothelialization was complete in both groups of stents, suggesting complete healing of the arteries.
Conclusions: In a 30-day porcine stent model, pimecrolimus inhibits neointimal proliferation as compared with bare metal stents. Also, the proof of concept of a dual drug eluting stent was established showing both safety and efficacy.