A Gene Therapy Update

A Gene Therapy Update from the Department of Ophthalmology and Visual Sciences Carver College of Medicine, and Institute for Vision Research at the University of Iowa

The pharmaceutical company Spark Therapeutics recently announced FDA approval [1,2] of a gene therapy known as Luxturna, which has been shown to improve vision in patients with an extremely rare inherited eye disease caused by mutations in the gene RPE65. Scientists estimate this disease to occur in less than one in 500,000 people – or about 560 people total in the United States [3,4]. 

The company has priced the drug at $425,000 per eye ($850,000 per patient), which does not include the cost of the surgery [5].

Many families who have members affected with an inherited eye disease have been encouraged by this development and are wondering whether and how it might affect them.

Here are some important facts:

Each specific gene therapy only works for a single disease. As a result, less than 1% of all patients with an inherited retinal disease (approximately three per thousand [3]) have a disease that might benefit from Luxturna treatment.

Retinal surgeons at the University of Iowa are experienced in Luxturna therapy. If you or your child have molecularly confirmed RPE65-associated retinal disease and you would like to talk to a physician about the possibility of receiving Luxturna treatment at the University of Iowa, you should email Dr. Stephen Russell at: steve-russell@uiowa.edu. Please attach an electronic copy of your genetic test result to this email. Dr. Russell or a member of his staff will contact you to discuss the next steps.

If you have had genetic testing at the University of Iowa in the past but now cannot remember whether the RPE65 gene causes your disease, you can email the Carver Nonprofit Genetic Testing Laboratory (carverlab@uiowa.edu) and ask whether you are known to have RPE65-based disease. While waiting for the reply, you should know that there is a greater than 99% chance that you do NOT have RPE65-associated disease. Please also note that the lab cannot discuss anything about a genetic test or research study (even its existence) with anyone other than the affected patients themselves (or the parents or guardians if the patients are minors).

If you have never had genetic testing but are now interested in knowing what gene is causing your disease, you should ask your current doctor to either help you arrange a genetic test or refer you to a doctor with specific interest in inherited retinal diseases who can arrange the test for you. Physicians who wish to order genetic tests through the Carver Nonprofit Genetic Testing Laboratory at the University of Iowa can do so by visiting our website at: https://www.carverlab.org.

If you do not currently have an eye doctor and would like to be seen in the Department of Ophthalmology at the University of Iowa, you can schedule an appointment by calling: 319-356-2852.

Few, if any, of the dozens of retinal gene therapies currently in clinical trial are expected to restore vision to affected patients. Most gene therapies are designed to slow or prevent further loss and are thus most useful for patients who still have quite a bit of vision remaining. The fact that Luxturna can restore some vision in affected patients is the result of RPE65’s unique role in the overall mechanism of human vision.

The 99.7% of inherited retinal disease patients who have other molecular forms of inherited retinal disease will each need a specific treatment designed to replace their specific disease-causing genes (if they are young enough to still have the majority of their retinal cells intact) or stem-cell-based photoreceptor cell replacement (if their disease is already very advanced).

Scientists at the University of Iowa Institute for Vision Research (IVR) believe that the cost of these treatments can eventually be reduced to less than $25,000 per patient (for gene therapy) and $50,000 per patient (for stem-cell-based photoreceptor cell replacement) if the therapies are manufactured in a nonprofit academic setting.

Individuals who would like to make a tax-deductible contribution to the University of Iowa’s Institute for Vision Research for the purpose of accelerating the development of treatments for inherited eye disease may do so by contacting Mitch Beckman at: Mitch.Beckman@foriowa.org or by following this link: www.givetoiowa.org/ivr.

Families interested in how rare eye disease genes are discovered may be interested in watching a short movie on this subject produced by the Howard Hughes Medical Institute: http://www.hhmi.org/biointeractive/search-mutated-gene


Friday, January 5, 2018