An 80-year-old woman from Oxford – Janet Osborne – has undergone the world's first gene therapy operation to target the root cause of age-related macular degeneration (AMD).
The condition is the most common cause of vision loss in the UK.
The surgery involved detaching the retina and injecting a solution containing viral particles at the back of Osborne's left eye, and was performed at John Radcliffe Hospital in Oxford, by Professor Robert MacLaren. The injected virus carried a modified DNA sequence able to correct the genetic mutation that causes AMD.
If the defective gene is successfully corrected with this approach, gene therapy would only need to be performed once.
'We're harnessing the power of the virus, a naturally occurring organism, to deliver the DNA into the patient's cells,' said Professor MacLaren of the University of Oxford.
'When the virus opens up inside the retinal cell it releases the DNA of the gene we have cloned, and the cell starts making a protein that we think can modify the disease...'
The aim of the therapy is not to restore sight but to halt the progress of the condition and preserve the vision of patients. This gene therapy could have a significant impact on the quality of life of people affected by AMD, including their ability to remain independent and carry out daily activities.
If successful, this approach could be used in the near future to stop the progression of AMD at an early stage of the disease, before vision starts deteriorating.
It is too early to know if Osborne's sight loss in her left eye has been halted, however she will attend regular monitoring visits to assess her vision stability during the course of the trial.
She told the BBC: 'I still enjoy gardening with my husband, Nick, who grows a lot of vegetables. If I can keep peeling and cutting the veg, and retain my current level of independence, it would be absolutely wonderful.'
The procedure was supported by the NIHR Oxford Biomedical Research Centre and it is the first of the FOCUS trial, a clinical study sponsored by Gyroscope Therapeutics, a UK-based company developing gene therapy products for the treatment of ocular diseases, such as AMD.