STK-002, an Antisense Oligonucleotide (ASO) for the Treatment of Autosomal Dominant Optic Atrophy (ADOA), is Taken Up by Retinal Ganglion Cells (RGC) and Upregulates OPA-1 Protein Expression After Intravitreal Administration to Non-human Primates (NHPs)

Abstract

Purpose : ADOA is the most common inherited optic neuropathy, starting in the first decade of life and resulting in severe and progressive visual decline due to loss of RGCs. Most patients harbor loss-of-function mutations in the OPA1 gene that lead to haploinsufficiency. Reduced OPA1 protein levels result in impaired mitochondrial function in RGCs leading to cell death. Currently, there is no treatment for patients with ADOA. Targeted Augmentation of Nuclear Gene Output (TANGO) ASOs, such as STK-002, reduce the inclusion of a non-productive, alternatively spliced exon in OPA1, and leverage the wild-type allele to increase productive OPA1 mRNA and protein. We previously demonstrated that TANGO ASOs can increase OPA1 protein levels in human cell lines, rabbit retina, and ADOA patient fibroblasts. In this study, we evaluated ASO localization and OPA1 protein levels in the retina following intravitreal administration of STK-002 to NHPs.

Methods : Cynomolgus monkeys (N=22) received bilateral intravitreal injections of vehicle or STK-002. Eyes were collected at 4 or 8 weeks after injection. Retinas were isolated for molecular analyses and whole globes were prepared for histology. Retinal OPA1 mRNA and protein were measured using qPCR (Taqman) and enzyme-linked immunosorbent assay (ELISA), respectively. A hybridization ELISA (HELISA) method was used to quantitate STK-002 levels in retina. Whole globes were sent for custom assay development and detection of STK-002 by miRNAscope™ in situ hybridization (ISH), and detection of OPA1 protein by immunofluorescence (IF).

Results : Retinal exposure of STK-002 increased in a dose-dependent manner and remained high at the last timepoint evaluated (Week 8). STK-002 also dose-dependently increased protein levels at Week 4, ranging from 31 to 47% compared to vehicle, and levels were maintained at Week 8. ISH and IF analysis demonstrated that both STK-002 and OPA1 protein levels increased in RGCs, the target cells for ADOA.

Conclusions : STK-002 produced a dose-dependent and persistent increase in OPA1 protein expression in the retinas of NHPs. ASO-induced increase in OPA1 protein levels in RGCs represents a potentially disease-modifying therapy for patients with ADOA.

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