AAV204, a Novel AAV Capsid, Demonstrates Superior Macular Transduction Following Para-Retinal Administration in Non-human Primates

Abstract

Purpose : To achieve the highest transduction levels, AAV administration to the eye has traditionally been performed by subretinal injection between the neural retina and underlying retinal pigmented epithelium. While this method provides the benefit of positioning the vector directly next to its cellular target, it requires retinal detachment, an operating room, and a trained retinal surgeon. A therapy that is administered directly into the vitreous of the eye could provide a safer and more feasible approach. Previously, we characterized a novel AAV capsid, AAV204, which facilitates transduction of both the inner and outer retina after intravitreal administration in mice and non-human primates. We hypothesized that using this capsid with a modified intravitreal injection, termed para-retinal injection, may produce more robust transduction levels, particularly in the macula and optic nerve.

Methods : Para-retinal administration was performed by layering the virus on top of the retina between the vitreous and the inner limiting membrane, thus not creating a subretinal detachment. 100 µL of viral suspension (1 x 10¹¹ total vector genomes) of AAV204.CBh.GFP or AAV8.CBh.GFP were administered to four non-human primate eyes. GFP expression was monitored using scanning laser ophthalmoscopy (SLO). 28 days post-injection, eyes were collected, processed, and analyzed by immunohistochemistry.

Results : SLO imaging of AAV204.CBh.GFP dosed eyes showed intense GFP expression in the macula, papillomacular bundle, and retinal nerve fibers. Immunohistochemistry imaging confirmed SLO analysis results, revealing high levels of GFP expression in the macula and foveal pit, as well as retinal ganglion cells and the associated retinal nerve fibers extending to the optic nerve. Alternatively, AAV8.CBh.GFP-injected animals showed little to no GFP expression in the macula or optic nerve. Of note, the dose used in this study was at least 10-fold lower compared to intravitreal AAV injections commonly used in the field.

Conclusions : These results suggest that para-retinal injection of AAV vectors, and more specifically using our novel AAV204 capsid, may be an efficient route of administration for drugs that target the macula or optic nerve/retinal ganglion cell layer.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.