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DNA

Gene therapy breakthrough

Researchers have successfully used gene therapy to improve the vision in people with a rare genetic cause of blindness, in the world’s first gene therapy trial for choroideremia.

Gene therapy alters or corrects inherited diseases at the level of the DNA. If successful, a single treatment might have life-long effects.

Choroideremia is an incurable disease caused by a defect in the CHM gene that causes progressive blindness in men.

This new trial involved giving 14 patients at Oxford University Hospitals NHS Foundation Trust a single injection into the back of the eye to deliver a healthy copy of the CHM gene to affected cells in the retina. By the end of the study there was a significant gain in vision across the group of patients as a whole.

Of the 12 patients who received the treatment without any complications, 100% either gained or maintained vision in their treated eyes. This improvement was sustained for up to 5 years at the last follow up. During this time only 25% of the untreated eyes that acted as controls maintained vision.

Professor Robert MacLaren the ophthalmologist who led the trial said: “The early results of vision improvement we saw have been sustained for as long as we have been following up these patients and in several the gene therapy injection was over 5 years ago. The trial has made a big difference to their lives.”

The research, published Nature Medicine was funded by the Health Innovation Challenge Fund, a partnership between Wellcome and the Department of Health and Social Care, and supported by the NIHR Oxford Biomedical Research Centre.

The success of the Oxford study has since led to a much larger international gene therapy trial involving over 100 patients across nine countries in the EU and in North America. It is now led by Nightstar Therapeutics, a gene therapy spin-out company established by the University of Oxford and Syncona to develop the treatment further.

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