Gene Therapy Approved to Treat Rare Cause of Vision Loss

The U.S. Food and Drug Administration has approved sales of a gene therapy treatment for an inherited condition that can cause blindness. Luxturna, from Spark Therapeutics, is the first gene therapy treatment for an inherited eye disease that has been approved in the United States. The approval had been expected since a positive report in October recommended its approval, after very successful clinical trials.

This treatment doesn’t restore normal vision. It allows patients to see shapes and light so they can get around without a cane or a guide dog. It is unclear how long the treatment will last, but so far most patients have maintained their vision for two years.

Luxturna is designed to help people who have a type of retinal dystrophy called Leber congenital amaurosis. And only patients whose disease is caused by a specific type of gene, the RPE65 gene, can use this new treatment. A genetic test is the only way to confirm if this treatment is appropriate for patients suffering from this inherited condition. Spark Therapeutics is offering access to genetic testing for select patients. More details will be available soon on their website. Genetic testing may also be available through a patient's insurance or non-profit organizations.

The treatment involves injecting a healthy version of the gene into the retina, where it replaces a damaged gene in retinal cells with a working version. These cells detect light and convert it into signals that the brain can understand.

Between 1000 and 2000 people in the United States are thought to have the kinds of retina problems that this treatment could help. Leber congenital amaurosis begins in infancy and progresses slowly, eventually causing complete blindness as the cells in the retina die. There is no other treatment available for this blinding disease.

This specific treatment won’t be able to help very many people. But its development may make it easier to create treatments for other, more common conditions in the future. It could be applied to retinitis pigmentosa, another inherited retinal disease caused by a defective gene. Researchers hope that one day gene therapy could help restore vision in more common diseases such as age-related macular degeneration.

The eye is a particularly promising area for gene therapy because it’s easy to see and get to, and because it has immune privilege. This means the body is less likely to reject the new cells introduced during treatment.

The price of Luxturna hasn’t been set yet, but it’s been making news amid speculations that it could cost more than a million dollars per treatment. A final price is expected to be set in January 2018. The treatment should be available to the public in early 2018.