( The first clinical trial to test a revo...)First clinical trial of gene therapy for childhood blindness

The trial involves adults and children who have a condition called Leber’s congenital amaurosis (LCA), which is a type of inherited retinal degeneration. This disease causes progressive deterioration in vision, due to an abnormality in a particular gene called RPE65. This defect prevents normal function of the retina, the light-sensitive layer of cells at the back of the eye. This results in severely impaired vision from a very young age and there are currently no effective treatments available.

The new technique that will be used in the trial involves inserting healthy copies of the gene into the cells of the retina to help them to function normally. Restoring the activity in these cells should restore vision. The operation delivers the normal genes to the retina, using a harmless virus or "vector" to carry the gene into the cells. The vector has been manufactured for this trial by Targeted Genetics, Seattle, USA.

Previous work using animal models has demonstrated that this gene therapy can improve and preserve vision. During trials, the vision of dogs with the defect was restored to the extent that they were able to walk through a maze without difficulty; something they could not do before the treatment. As this trial is the first to treat an eye disease using administration of gene therapy vectors to human retinas, the team have carried out extensive pre-clinical testing. The purpose of this trial is to find out how safe and effective the new intervention is in humans.

The team conducting the trial, from UCL Institute of Ophthalmology and Moorfields Eye Hospital, is led by Professor Robin Ali and includes leading eye surgeon Mr
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Source:University College London