Stereopure oligonucleotide treatment results in durable rescue of disease phenotype in a P23H hRHO pig model of human autosomal dominant retinitis pigmentosa (adRP)

Abstract

Purpose : AdRP is an inherited retinal disease that affects ~400,000 people worldwide. In the United States, ~2500 people have a proline to histidine substitution at codon 23 (P23H) in rhodopsin (RHO). It is believed that misfolded mutant Rho protein contributes to rod photoreceptor (rod) death. Wave Life Sciences has previously reported that stereopure antisense oligonucleotides (ASOs) bind to RNA via complementary base pairing that promotes RNase H–mediated degradation of mutant RNA. Here we evalutated the efficacy of stereopure ASOs targeting P23H hRHO mRNA injected into the vitreous of transgenic P23H hRHO (TgP23H hRHO) pigs on retinal structure and function.

Methods : Four neonatal TgP23H hRHO pigs received bilateral intravitreal (IVT) injections (50 uL) of ASOs targeting the P23H hRHO mutation at 10 µg (n=2) or 25 µg (n=2). Controls included: TgP23H hRHO eyes injected with PBS (n=1), or non-targeting ASO (n=3; 25 µg), and uninjected age-matched WT and TgP23H hRHO eyes. Presence of ASO in retina (retinal exposure), aqueous, vitreous and RPE were assessed by hybridization ELISA. We conducted regular ocular exams, fundus imaging, full-field ERGs and OCTs to assess tolerability and efficacy of ASOs on retina structure and function. Animals were euthanized at 8 (n=5) or 16 (n=3) weeks post injection (wpi). Morphological assessments were conducted in immunohistochemically labeled frozen sections.

Results : PK analysis found dose and time dependent retinal exposure (25 µg dose: 5 and 2 µg/g at 8 and 16 wpi, respectively; 10 µg dose: 0.7 and 0.2 µg/g at 8 and 16 wpi, respectively). ASOs did not induce inflammation and rejuvenated rod structure and function in treated retinas. Naïve and PBS injected TgP23H hRHO pigs had no scotopic ERG b-wave (flash intensity; 0.01 cd*s/m² ). At 16 wpi, all Tg retinas treated with 25 µg of targeting ASO had scoptopic b-waves of whose amplitudes were ~40% of WT. Rod morphology and rhodopsin expression were preserved compared to untreated Tg littermates.

Conclusions : InTgP23H hRHO pigs, a single IVT injection of an ASO targeting P23H hRHO is well tolerated, preserves rod morphology and rhodopsin expression, and rejuvenates rod function for at least four months after administration. This represents a strong resolution of rod photoreceptor degeneration.

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