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Gene Therapy Treats all Mutation Types

Oct 27 2018

Posted In:

20/20 Blog

Chicago, IL — At the American Academy of Ophthalmology meeting, Stanford ophthalmologist, Vinit Mahajan M.D., Ph.D., presented a poster detailing results on the relationship between specific patient mutations and clinical outcomes in the first FDA approved gene therapy trial in humans.

The gene augmentation therapy, Luxturna, was given to correct a childhood blinding eye disease called Leber’s Congenital Amaurosis.

One year after surgery to deliver a normal gene to the retina, 27 of the 29 patients enrolled in the trial had improved visual function. In the phase-3 trial, patients were able to complete an obstacle-course maze, known as a Multi-Luminance Mobility Test, in very low light conditions that was previously impossible.

The RPE65 gene is just one of several genes linked to Leber’s Congenital Amaurosis. Thirty-four distinct mutations were identified in the study. Most of these mutations were previously known to cause disease, but others were new. These new gene mutations are referred to as “variants of unknown significance,” since scientists were not certain whether gene therapy would be helpful. 

Fortunately, the trial showed it did not matter what type of mutation a patient had. There was a positive response for all mutation types. So, as long as a patient has a clinical and genetic diagnosis consistent with RPE65–associated Leber’s Congenital Amaurosisthey can be considered for Luxturna gene therapy.

Title: RPE65 Mutation Subtype Effect on Baseline Visual Function and Treatment Response in Phase 3 Voretigene Neparvovec Trial 

Authors:Vinit B. Mahajan, Jean Bennett, Albert Maguire, Julia Haller, Bart P. Leroy,Elliott H. Sohn, Arlene Drack, Christina M. Ohnsman, Thomas Ciulla, Daniel Chung,Katherine A. High,Stephen Russell 

Mahajan is a consultant for Spark Therapeutics.