Gene therapy improves sight in near-blind patients

By Deena Beasley and Ben Hirschler

LOS ANGELES/LONDON (Reuters) - Gene therapy for a rare type of inherited blindness has improved the vision of four patients who tried it, boosting hopes for the troubled field of gene repair technology, scientists said on Sunday.

Two separate teams of doctors reported successes in using gene therapy to treat Leber congenital amaurosis, or LCA.

LCA damages light receptors in the retina. It usually begins affecting sight in early childhood and causes total blindness by the time a patient is 30. There is no treatment.

Both teams used a common cold virus to deliver a normal version of one damaged gene that causes the disease, called RPE65, directly into the eyes of patients.

Although both trials were only testing for safety, patients reported they could see a little better afterwards, the researchers told a meeting of eye specialists in Florida and also reported in the New England Journal of Medicine.

Dr. Katherine High of the Children's Hospital of Philadelphia and the Howard Hughes Medical Institute and colleagues said all three of their volunteers had improved vision after the treatments.

Dr. Robin Ali of University College London and colleagues said one of their three volunteers got better.

Because the patients were adults, already had severe sight loss and received only low doses of treatment, researchers had not expected to see a benefit at all.