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Trial evaluating gene therapy for hereditary blindness commences
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GAINESVILLE, Fla. — A gene transfer technique is now being tested in a phase 1 clinical study for treating Leber's congenital amaurosis type 2, according to a press release from the University of Florida.
One volunteer patient has received an injection of genes into the retina of one eye. The injection was performed by Shalesh Kaushal, MD, PhD, assistant professor of ophthalmology at the University of Florida.
Six adults and three children between the ages of 8 and 17 years are scheduled to undergo the procedure at the university over the next year. Potential risks are discussed with prospective participants as part of an extensive screening and informed consent process, according to the release.
Researchers have found that Leber's congenital amaurosis type 2 is caused by mutations in the RPE65 gene, which causes photoreceptor cells to be unable to respond to light.
The current study is evaluating the use of a harmless, modified adeno-associated virus, which already exists in most people, to deliver RPE65 to the retina, the release said.
"The procedure involves two incisions that give the surgeon access to the surface of the retina," Dr. Kaushal said in the release. "Then, fluid containing the virus is injected with a syringe and it creates a bubble. The virus will then be taken up by the photoreceptor cells and the retinal pigment epithelial cells and will theoretically produce the protein that these patients are missing."
William W. Hauswirth, PhD, Rybaczki-Bullard professor of ophthalmic molecular genetics at the University of Florida, and Samuel G. Jacobson, MD, PhD, professor of ophthalmology at the University of Pennsylvania, were among a multicenter team that first established proof-of-concept for gene transfer for Leber's congenital amaurosis in rodent models of the disease and in a breed of vision-impaired dogs.
After preclinical safety studies in these animals, including demonstration of safety in non-human primates, the investigators began the human clinical trial.