Intramural delivery of recombinant apolipoprotein A-IMilano/phospholipid complex (ETC-216) inhibits in-stent stenosis in porcine coronary arteries

Background-We have previously demonstrated vasculoprotective effects after repeated intravenous administration of recombinant apolipoprotein A-I-Milano (apoA-I-m)/phospholipid complex. In this study, we sought to determine the effects of local recombinant apoA-I-m/1-palmitoyl, 2-oleoyl phosphatidylcholine complex (ETC-216) delivered intramurally via the Infiltrator catheter on luminal narrowing in a porcine coronary artery stent overstretch injury model. Methods and Results-In twelve domestic swine (approximate to25 kg), two arteries each were infiltrated with 0.4 mL ETC-216 (14 mg/mL) or vehicle control immediately before deployment of GFX stents (stent: artery ratio=1.3:1). Animals were euthanized at day 28, and evaluation by QCA revealed a significant improvement in mean lumen loss index with ETC-216 treatment (21+/-22% versus 43+/-13% lumen loss; P=0.01). Histomorphometric analysis showed that ETC-216 treatment significantly reduced the intimal area (6.7+/-1.5 versus 5.2+/-1.4 mm(2), -22%; P=0.02) and the stenosis index (0.76+/-0.15 versus 0.59+/-0.15; P=0.01), and increased the lumen area (2.1+/-1.4 versus 3.7+/-1.8 mm(2), +76%; P=0.02). Regression analysis showed significant differences in lumen area (P=0.004), neointimal area (P=0.003), stenosis index (P=0.001), and neointimal thickness (P=0.003) adjusted for injury score in favor of ETC-216. Conclusions-A single intramural administration of ETC-216 significantly inhibited injury-induced luminal narrowing in the porcine stent overstretch model through reduction of intimal hyperplasia. These data show that local intracoronary delivery of ETC-216 may be useful to prevent restenosis after coronary stenting.