Biological effect on restenosis and vascular healing of encapsulated paclitaxel nanocrystals delivered via coated balloon technology in the familial hypercholesterolaemic swine model of in-stent restenosis.

Aims: The aim of this study was to evaluate the biological efficacy of a novel lower-dose (2.5 µg/mm2) encapsulated paclitaxel nanocrystal-coated balloon (Nano-PCB) in the familial hypercholesterolaemic swine (FHS) model of iliofemoral in-stent restenosis.

Methods And Results: Nano-PCB pharmacokinetics were assessed in 20 femoral arteries (domestic swine). Biological efficacy was evaluated in ten FHS: 14 days following bare metal stent implantation each stent segment was randomised to a clinically available PCB (IN.PACT, n=14), the Nano-PCB (n=14) or an uncoated balloon (n=12). Angiographic, optical coherence tomography and histological evaluation was performed at 28 days after treatment. Arterial paclitaxel concentration was 120.7 ng/mg at one hour and 7.65 ng/mg of tissue at 28 days with the Nano-PCB. Compared to the control uncoated group, both PCBs significantly reduced percent area stenosis (Nano-PCB: 36.0±14.2%, IN.PACT: 29.3±9.2% vs control: 67.9±15.1%, p<0.001). Neointimal distribution in the entire stent length was more homogenous in the Nano-PCB. Histological evaluation showed comparable degrees of neointimal proliferation in both PCBs; however, the Nano-PCB showed slightly higher levels of neointimal maturity and endothelialisation.

Conclusions: Lower-dose encapsulated paclitaxel nanocrystals delivered via a coated balloon displayed comparable biological efficacy with superior healing features compared to a clinically validated PCB technology.