Gene therapy for inherited blindness improves sight
28 April 2008
The results, published today in the 'New England Journal of Medicine', show that the experimental treatment is safe and can improve sight. The findings are a landmark for gene therapy technology and could have a significant impact on future treatments for eye disease.
Launched in February 2007, the trial involved young patients with a condition called Leber's congenital amaurosis (LCA), a rare inherited eye disease caused by an abnormality in the gene RPE65. The condition appears at birth or in the first few months of life and causes progressive deterioration of the retina and loss of vision. There are currently no effective treatments available.
In the trial, healthy copies of the RPE65 gene were inserted into the cells of the retina to help them to function normally. This involved an operation to deliver a harmless virus or 'vector' to the retina, which then carried the gene into the cells.
Crucially, as well as showing that the experimental treatment can benefit vision in young adults who already have advanced retinal disease, the study found no side effects in this trial.
Following the treatment, the three patients all achieved levels of vision at least equivalent to before the operation, but one patient showed significantly improved night vision. The researchers believe the operation's success for this particular patient could be because his disease had not progressed to the same extent as the others.
The other two patients may also still benefit from the new treatment in the future, but it will be some time before this becomes apparent. The team have already begun to trial the technique in younger patients, where they hope to achieve even better results.
The team conducting the trial was led by Professor Robin Ali and included eye surgeon Mr James Bainbridge (pictured), a Wellcome Trust Advanced Fellow at the Institute of Ophthalmology, and Professor Adrian Thrasher, a Wellcome Trust Senior Clinical Fellow at the Institute of Child Health.
Image: James Bainbridge; Moorfields Eye Hospital
References
Bainbridge J et al. Effect of gene therapy on visual function in Leber’s congenital amaurosis. N Engl J Med [Epub ahead of print on 28/04/2008].