Blind get hope through gene therapy
Treatments have helped increase light sensitivity and improve vision for patients with Leber's, a rare form of visual impairment.
For the first time, researchers have used gene therapy to increase light sensitivity and improve vision in patients who were virtually blind, a finding that offers new hope to hundreds of thousands of patients with inherited forms of vision impairment.
Although the patients had an extremely rare form of blindness called Leber's congenital amaurosis, researchers believe the approach can ultimately be used for a much broader spectrum of disorders, including retinitis pigmentosa and macular degeneration.
The treatment, so far meant only to prove the safety of the technique, produced "real clinical benefit" and "made a real difference in patients' lives," said geneticist Robin R. Ali of University College London, the senior author of one of two reports presented Sunday at a Fort Lauderdale, Fla., meeting of the Assn. for Research in Vision and Ophthalmology.
The reports were also published online today by the New England Journal of Medicine.
"The fact that they had patients who could now read lines on an eye chart . . . and one who could run an obstacle course -- this is a really great advance," said geneticist Stephen Rose, chief research officer of the Foundation Fighting Blindness, who was not involved in the research. "This has changed the landscape of hope for patients," he added.
Added Dr. Morton F. Goldberg, an ophthalmologist at John Hopkins University's Wilmer Eye Institute, "In the field of retinal dystrophies, this is, I believe, the most important therapeutic discovery" in four decades. "It's a landmark."
The results are particularly important because gene therapy, in which a good gene is substituted for a naturally occurring defective one, has been "a snakebitten field," with at least two subjects in other experiments dying and a handful of others developing cancer, said Dr. Albert M. Maguire of the University of Pennsylvania School of Medicine, the lead author of the second report.
A handful of children with severe combined immunodeficiency disease have been successfully treated, but critics have charged that they could have been treated equally effectively -- and more safely -- with conventional treatments. And three children treated for the condition in France developed leukemia because the delivery agent that was used inserted the new gene at the wrong location.
Researchers have also reported some modest benefits in gene therapy for Parkinson's disease, but none so dramatic as the new findings with Leber's
