In vivo preclinical evaluation of YntraDose™ in pig's lung: A pilot study of a ⁹⁰Y-microsphere device implantation

YntraDose™ is a novel injectable radiotherapeutic formulation combining BioGlue® (bovine serum albumin-glutaraldehyde polymer) with Yttrium-90 resin microspheres. This pilot preclinical feasibility study represents the first in vivo evaluation of YntraDose™ administration into lung tissue and was designed to assess its injectability, polymerization performance, biodistribution, dosimetry, and tissue response.

Seven healthy female Landrace pigs were enrolled and received ultrasound-guided percutaneous injections of YntraDose™ in two lung lobes (5 ml and 10 ml syringes targeting 150-185 MBq). Pigs were euthanized at 24 h, 7-, 14-, and 21 days post-injection for necropsy, PET/CT imaging, dosimetry, and histological evaluation. Immunohistochemistry for IL-1β, IL-6, and IL-8 was performed on lung biopsies to assess inflammatory activity.

YntraDose™ administration was feasible and resulted in localized polymerization within the injection site, with no evidence of radioactivity spread to other organs. Histological analysis revealed areas of necrosis extending up to 1-1.5 cm from the main deposition site and diffuse inflammatory cell infiltration. IL-1β, IL-6, and IL-8-positive cells were identified throughout the tissue, indicating a strong inflammatory response.

This first in vivo preclinical investigation demonstrates that YntraDose™ can be successfully injected and polymerized in lung tissue, even at high radioactivity levels. Despite the intense inflammatory reaction observed, the results support further preclinical studies with optimized, clinically relevant ⁹⁰Y activities to evaluate the potential of YntraDose™ for localized lung tumor ablation.