AAV-mediated gene therapy approach for the treatment of Leber congenital amaurosis retinopathies resulting from NPHP5 mutations

Leber congenital amaurosis (LCA) is an autosomal recessive disorder characterized by retinal dystrophy and severe visual impairment within the first year of life. LCA occurrence, while rare (1/50,000 – 1/33,000 of live births), is the leading cause of childhood blindness. Due to its early onset, LCA has been more challenging to treat as opposed to later onset retinopathies such as retinitis pigmentosa.

To date, at least 15 different mutated genes have been associated with LCA. Of these 15 different genes, one (RPE65) is currently the subject of multiple ongoing gene therapy clinical trial studies. This particular gene mutation only accounts for approximately 16% of all LCA cases, therefore additional therapeutic approaches are needed so that a larger population of LCA patients have treatment options.

Work in the laboratories of Drs. Gustavo Aguirre, William Beltran, Samuel Jacobson, and Artur Cideciyan has resulted in the development of an AAV-mediated gene therapy approach for treating LCA disorders arising from a mutation in the Nephrocystin-5 (NPHP5) gene. Using a large animal model system, the team has observed a robust recovery of retinal function and sustained vision for periods greater than 2 years after injection with the construct.

• First long-term successful gene therapy of a ciliopathy causing LCA.
• Different AAV vectors provide effective therapeutic rescue.
• Successful treatment in early, mid and more advanced stages of the disease.
• Efficacy demonstrated in a large animal model (human-size eye) affected by a naturally-occurring form of NPHP5-LCA.