A Novel Device for Suprachoroidal Drug Delivery to Retina: Evaluation in Nonhuman Primates

Purpose: Evaluation of distribution and tolerance of suprachoroidal injection of indocyanine green (ICG) in nonhuman primates (NHPs) using a novel suprachoroidal (SC) delivery technology.Methods: Three live and three euthanized African green monkeys were injected with 150 or 200 [IL ICG/eye into the SC space of both eyes, 2.5 mm posterior to the limbus in the inferior quadrant, utilizing a novel SC injector. Eyes were analyzed by imaging of scleral flatmounts. Live animals were observed for 24 hours for general health. Ophthalmic evaluation included slit-lamp biomicroscopy, tonometry, fundus imaging, confocal laser ophthalmoscopy, and spectral-domain optical coherence tomography (SD-OCT) before and at 10 minutes and 1, 3, and 24 hours post-injection.Results: SC dosing was successfully performed in all eyes. Infrared fundus imaging demonstrated ICG distribution throughout the posterior segment, reaching the macula within 24 hours post-injection. No inflammation, intravitreal penetration, SC blebs, retinal detachment, or hemorrhages were detected. No significant changes were observed in retinal thickness by SD-OCT (P = 0.267, ANOVA). A mild, statistically insignificant elevation in intraocular pressure was observed within 10 minutes post-injection (mean +/- standard error: 7.28 +/- 5.09 mmHg; P = 0.061) and was spontaneously resolved within the first hour after dosing.Conclusions: Suprachoroidal injection of 150 to 200 [IL ICG dye was successfully performed and well tolerated in NHP eyes, with rapid distribution into the macular region and throughout the posterior pole.Translational Relevance: This novel SC drug delivery system may potentially provide safe and effective delivery of therapeutics to the posterior pole region in humans.