Long-Term Structural Outcomes of Late-Stage RPE65 Gene Therapy.

Abstract

The form of hereditary childhood blindness Leber congenital amaurosis (LCA) caused by biallelic RPE65 mutations is considered treatable with a gene therapy product approved in the US and Europe. The resulting vision improvement is well accepted, but long-term outcomes on the natural history of retinal degeneration are controversial. We treated four RPE65-mutant dogs in mid-life (age = 5-6 years) and followed them long-term (4-5 years). At the time of the intervention at mid-life, there were intra-ocular and inter-animal differences in local photoreceptor layer health ranging from near normal to complete degeneration. Treated locations having more than 63% of normal photoreceptors showed robust treatment-related retention of photoreceptors in the long term. Treated regions with less retained photoreceptors at the time of the intervention showed progressive degeneration similar to untreated regions with matched initial stage of disease. Unexpectedly, both treated and untreated regions in study eyes tended to show less degeneration compared to matched locations in untreated control eyes. These results support the hypothesis that successful long-term arrest of progression with RPE65 gene therapy may only occur in retinal regions with relatively retained photoreceptors at the time of the intervention, and there may be heretofore unknown mechanisms causing long-distance partial treatment effects beyond the region of subretinal injection.

• Authors: Kristin L Gardiner, Artur V Cideciyan, Malgorzata Swider, Valérie L Dufour, Alexander Sumaroka, András M Komáromy, William W Hauswirth, Simone Iwabe, Samuel G Jacobson, William A Beltran, Gustavo D Aguirre
• Journal: Molecular therapy : the journal of the American Society of Gene Therapy (Mol Ther) Vol. 28 Issue 1 Pg. 266-278 (01 08 2020) ISSN: 1525-0024 [Electronic] United States
• PMID: 31604676 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2019 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Chemical References

• retinoid isomerohydrolase
• cis-trans-Isomerases

Topics

• Animals
• Disease Models, Animal
• Dogs
• Electroretinography
• Female
• Follow-Up Studies
• Genetic Therapy (methods)
• Leber Congenital Amaurosis (diagnostic imaging, therapy)
• Mutation
• Photoreceptor Cells, Vertebrate (metabolism)
• Retina (diagnostic imaging, metabolism)
• Retinal Degeneration (diagnostic imaging, genetics)
• Treatment Outcome
• Vision, Ocular
• cis-trans-Isomerases (genetics)