O15 Assessment of distal penetration, radiopacity, and biological safety response of NeoCast(TM), a unique solvent-free, non-adhesive embolic material

<h3>Introduction</h3> NeoCast^TM is a solvent-free, shear-responsive, <i>in-situ</i> curing biomaterial designed for embolization applications where complete casting and occlusion of micron-sized vessel branches is desired. <h3>Aim of Study</h3> Assess the preclinical performance of NeoCast with respect to distal penetration, radiopacity, and biological (vascular and brain tissue) safety response. <h3>Methods</h3> NeoCast embolization and safety performance was evaluated in a swine kidney model at 7, 30, and 90 days (n=8 injections/timepoint). Onyx-18® (Medtronic) and polyvinyl alcohol particles (PVA, Cook 90-180 micron) were used as controls (n=6 injections/timepoint). Distal penetration and radiopacity were assessed via micro-computed tomography imaging of explanted kidneys. Histopathology consisted of assessing fibrosis, necrosis, and inflammatory local vascular responses. Neurotoxicity was assessed at 7 (n=4) and 90 (n=8) days by injecting NeoCast directly into rabbit brain parenchyma allowing <i>in-situ</i> cure. High density polyethylene rods were used as negative controls. Neuropathological evaluation consisted of characterizing inflammatory response and necrosis. <h3>Results</h3> NeoCast occluded ~5.2x more vessel branches compared to Onyx-18 (p=0.006). Histologically, NeoCast was present more frequently in smaller arteries (&lt;200µm) compared to PVA (64% vs 15%, p&lt;0.001). Radiographically, NeoCast embolic casts exhibited a homogeneous appearance with minimal artifact. NeoCast local vascular response was similar to Onyx-18 and PVA: inflammation was mild and stable throughout 90 days, indicative of a non-degrading, bioinert material. NeoCast elicited a benign neurotoxic response with minimal inflammation and no necrosis. <h3>Conclusion</h3> NeoCast exhibits superior distal penetration and radiopacity compared to commercially available embolics and elicits safe vascular and brain tissue responses in animal models. Future studies evaluating NeoCast in human subjects are warranted. <h3>Disclosure of Interest</h3> no.