Gene therapy aimed at curing blind children
IAN SAMPLE
BRITISH SCIENTISTS are to launch the world's first clinical trials of a controversial gene therapy to cure childhood blindness.
Researchers will test the treatment on volunteers with a rare inherited form of blindness, in which a single defective gene causes the retina to degenerate and eventually stop working as the child grows up.
The condition is called Leber's congenital amaurosis and children born with the defective gene are often completely blind by their 20s. If the trials are a success, it could revolutionise the treatment of more than 100 inherited forms of blindness.
Patients taking part in the trial will be injected with a virus modified to carry a correct version of the faulty gene.
Once inside the eye, the virus ferries the healthy gene into the cells that make up the retina, halting and even reversing the damage caused.
Phase 1 trials
The phase 1 trials are designed to assess the safety and efficacy of the treatment in 12 patients and will be carried out by the Institute of Ophthalmology at University College London (UCL) and nearby Moorfields Eye Hospital.
The safety of the treatment will be under particular scrutiny, following a gene therapy trial four years ago in which two children being treated for a rare immune disorder called Scid (severe combined immunodeficiency) developed leukaemia.
Trials of the latest gene therapy in dogs have proved the treatment can improve and preserve vision enough for nearly blind animals to negotiate mazes.
The researchers will know whether the treatment has worked in a few months.
"It will be many months before we have the full picture. We anticipate the best outcome in younger patients, as we will be treating the disease in the early stages of its development," said Tony Moore, a leading retinal specialist on the team.
— Guardian Newspapers Limited 2007
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