LOS ANGELES - Researchers using gene therapy have made significant improvements in vision in 12 patients with a rare inherited visual defect, a finding that suggests it might be possible to produce similar improvements in a much larger number of patients with retinitis pigmentosa and macular degeneration.
The team reported success with three adult patients last year, an achievement that was hailed as a major accomplishment for gene therapy. They have now treated an additional nine patients, including five children, and find that the best results are achieved in the youngest patients, whose defective retinal cells have not had time to die off.
The study, by researchers at the Children’s Hospital of Philadelphia and the University of Pennsylvania School of Medicine, was published online by the journal Lancet.
The 12 patients suffered from Leber’s congenital amaurosis, which affects about 130,000 worldwide. Victims are born with severely impaired vision that deteriorates until they are blind, usually by adolescence. There is no treatment.
The youngest patient, Corey Haas, 9, was considered legally blind before the treatment began. He was confined largely to his house and driveway when playing, had immense difficulties in navigating an obstacle course, and required help in the classroom. Today, after a single injection of a gene-therapy product in one eye, he rides his bike, needs no assistance in the classroom, navigates the obstacle course quickly and has even played his first game of softball.
