First Gene Therapy Clinical Trial Proves Successful
Researchers from the University College London Institute of Ophthalmology and the Biomedical Research Centre of Moorfields Eye Hospital, National Institute for Health Research (United Kingdom), have announced results from the world's first clinical trial to test a revolutionary gene therapy treatment for a type of inherited blindness. The fields of ophthalmology and clinical research have been abuzz since the April 27, 2008, online prepublication of their article, entitled "Effect of Gene Therapy on Visual Function in Leber's Congenital Amaurosis" (available at http://content. nejm.org/cgi/content/full/NEJMoa0802268v1), which demonstrated improvements to the sight of a participant with genetic blindness. The findings represent a landmark in gene therapy technology and could have a significant impact on future treatments for eye diseases.
The trial presented in the article involved three young adult patients with Leber's congenital amaurosis, a rare inherited eye disease caused by an abnormality in a gene called RPE65. The condition appears at birth or in the first few months of life and causes progressive deterioration and loss of vision, and there are currently no effective treatments available for the condition. The trial's purposes were to find out whether gene therapy for retinal disease is safe and to find out if it can improve vision in young adults who already have advanced retinal disease. The technique used in the trial involved inserting healthy copies of the missing RPE65 gene into the cells of the participants' retinas to help them to function normally.
Explaining the technique, Dr. Bainbridge, who led the surgical team, said:
We developed surgical techniques to enable access to the cells beneath the retinas of patients, using a very fine needle to deliver the modified virus in a controlled retinal detachment that resolves as the vector is absorbed. It is tremendously exciting to see that this technique is safe in an extremely fragile tissue and can improve vision in a condition previously considered wholly untreatable.
The trial was a success in regard to its first purpose, as the experimental treatment was found to cause no serious side effects.
The second aim of the study was analyzed in a series of tests designed to establish the effects of the therapy on the vision of the three patients. …