Gene therapy researchers at UMass Medical School focused on degenerative retinal diseases are calling a promising new study out of the University of Oxford the “future” of gene therapy, after clinical trial participants with a rare eye disease experienced significant improvement in their vision.
“This therapy used the AAV [adeno-associated viral] vector. The viral delivery with AAV is extremely safe and I think it is going to be the future of gene therapy, especially in the eye because it is easy to target a multitude of cells,” said Claudio Punzo, PhD, assistant professor of ophthalmology, who was not involved in the Oxford study. “It holds the promise of treatment for many other retinal diseases.”
The small trial targeted a faulty gene in the eye that causes choroideremia, an inherited disease that begins with night blindness and progresses to total blindness. Using AAV vectors to carry healthy versions of the targeted gene to the eye, the treatment produced significantly improved vision in all participants, even those who had just begun to have impaired vision at the start of the trial. The study results were published in The Lancet.
While only a relatively small number of people—and almost exclusively males—are affected by choroideremia, retinitis pigmentosa is a similar but more common disease of the rods and cones that affects many more.
“The incidence of choroideremia is about one in 50,000, whereas retinitis pigmentosa is a relatively more frequent disease that affects one in 3,000 to 4,000,” said Hemant Khanna, PhD, assistant professor of ophthalmology, who was also not involved in the Oxford study. “This treatment does hold promise for such diseases as retinitis pigmentosa where we can now target photoreceptors. In our lab, we are working on designing treatment strategies for some forms of retinitis pigmentosa.”