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Success of Vision Gene Therapy Could Mean Greater Availability

The success of a 15-year-old’s gene therapy has begun to pave the way for vision health care in North America. Treatment to reverse the blinding effects of a rare genetic disease related to the retina now has a future in clinics and hospitals in America and hopefully soon around the world.


Molly Troxel of Iowa was born with Leber congenital amaurosis, a faulty gene that causes the tissue at the back of the eye that detects light and colour to become damaged. Serious visual impairment begins to degrade in childhood, eventually fading to near or total blindness.


Undergoing twin eye surgeries, Troxel was injected with a virus that was essentially loaded with correct copies of her faulty gene as part of a clinical trial on this new type of gene therapy. Now a few years after the first surgeries, she can see well enough to consider driving a car.


At the end of last year, the U.S. Food and Drug Administration approved the therapy Troxel received, called Luxturna. The treatment is the first gene therapy in the United States for an inherited disease and the first in which a corrective gene is given directly to the patient.


Luxturna works by delivering a normal copy of the RPE65 gene directly to retinal cells. These retinal cells then produce the normal protein that converts light to an electrical signal in the retina to restore patient’s vision loss. Luxturna uses a naturally occurring adeno-associated virus, which has been modified using recombinant DNA techniques, as a vehicle to deliver the normal human RPE65 gene to the retinal cells to restore vision.


In the coming years, the FDA begin issuing disease-specific guidance documents on the development of gene therapy products to lay out modern and more efficient parameters. This will help guide other countries who are hoping to explore use of the gene therapy, including Canada. Right now, the Foundation Fighting Blindness is communicating with Health Canada and provincial regulatory bodies to ensure that innovative treatments like Luxturna are accessible to Canadians.


For more information on other technologies that could cure blindness, check out the FYidoctors blog.