Zap of radiation to tackle leading cause of blindness
15 June 2017 - New hope for patients with Wet Age-Related Macular Degeneration (AMD)
A clinical trial is using a robotically-controlled system to deliver highly-targeted, low-dose radiotherapy to treat patients with Wet Age-Related Macular Degeneration (AMD) in the hope of eradicating or reducing eye injections.
The nationwide study, funded by an NIHR and MRC partnership and led by clinicians at King’s College Hospital in London, is giving new hope to patients with the condition who until now have faced regular eye injections to preserve their vision.
In the one-off, non-invasive treatment, three rays of radiotherapy are beamed through the white of the eye to overlap at the macula. The therapy is delivered by an eye doctor using a robotically-controlled machine to ensure precision treatment. The total dose of radiation received by the body is about the same as a mammogram.
AMD, of which there are two main types (Wet and Dry), affects patients over 50 and is the leading cause of sight loss in the UK. The condition develops when the part of the eye responsible for central vision (the macula) is unable to function as effectively as it used to. Wet AMD – the more serious form of the condition – occurs when abnormal blood vessels form underneath the macula and damage its cells. Without treatment, vision can deteriorate within weeks or even days.
The standard treatment for Wet AMD involves the injection of drugs into the eye targeting a chemical called vascular endothelial growth factor (VEGF), which causes the condition. The injections do not cure Wet AMD but they help to preserve sight. It is anticipated that the new treatment will reduce or eliminate the need for further eye injections. Studies have already shown that in carefully selected patients stereotactic radiotherapy can reduce eye injections by about half, with many patients needing no further injections at all, and vision was better than in those who only received eye injections.
If proved successful, the new treatment will not only be more convenient for patients, who currently have to visit an eye clinic on a regular basis, but it will also be more cost-effective for the NHS. Each dose of the injection costs around £800 and needs to be repeated several times each year, whereas the radiotherapy treatment costs £1,250 but is required only once.
Tim Jackson, Consultant Ophthalmic Surgeon at King’s College Hospital, who is leading the trial, said, “Age-related macular degeneration causes more blindness in the UK than all other eye diseases combined. It is very common, and the risk increases with age so that by age 90 one in five people has the condition, with 600,000 affected in the UK.
“Initial results with stereotactic radiotherapy have been promising, with some patients experiencing a marked improvement in the quality of their vision, and some no longer requiring injections.
“As well as being a less invasive treatment, we anticipate it will result in better outcomes for patients by addressing the cause of the condition rather than just suppressing it with eye injections.
“Whilst not all patients are suitable for this new technology, for those who are we hope to reduce the burden of having to attend very regular clinic appointments. It should also save the NHS money – so it appears to be win-win.”
The randomised trial treats two-thirds of participants with the active treatment and one-third with a placebo. The standard treatment of eye injections is continued on patients throughout the trial, if they need it.
The trial is currently accepting patients, with about 20 participating hospitals across the UK. Patients can find their nearest participating hospital and details on whether they are suitable for the trial by visiting www.starstudy.org.uk. For further enquiries about the trial, patients can email email@example.com or phone 020 3299 1297.
The nationwide trial, which is funded by an NIHR and MRC partnership, is called the STAR study and builds on the success of the INTREPID study for Wet AMD.
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