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 a rare form of blindness called Leber's congenital amaurosis, researchers believe the approach can ultimately be used for a broad spectrum of disorders, including retinitis pigmentosa and macular degeneration.
The experiments, 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 published online Sunday 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."
Technique controversial
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 defective gene is replaced with a good one, has been "a snakebitten field," with at least two subjects in other experiments dying and a few others developing cancer, said Dr. Albert M. Maguire of the University of Pennsylvania School of Medicine, lead author of the second report.
A handful of children with severe combined immunodeficiency disease were successfully treated, but critics charged that conventional treatments would have been equally effective -- and safer. In France, three children treated for the disease developed leukemia because the delivery agent inserted the new gene in the wrong place.
Researchers have reported modest benefits for Parkinson's disease, but no gene therapy results have been as dramatic as the Leber's findings.
