A treatment for the commonest cause of blindness could be available within five years, scientists believe, after revealing the first two patients given a revolutionary stem cell therapy have regained enough vision to be able to read.
The two patients have advanced AMD – age-related macular degeneration – which destroys the central vision. Both were losing their sight. They were, said their surgeon, unable to see a book, let alone the printed letters.
But an implanted “patch” of stem cells over the damage at the back of the eye has restored the central vision enough not only for reading but to see faces that used to be a grey blur.
In the future, the scientists behind the breakthrough anticipate the procedure could be as common as cataract surgery, helping large numbers of the 600,000 to 700,000 people in the UK who are losing their sight because of AMD.
The breakthrough comes from the London Project to Cure Blindness, a collaboration between Prof Pete Coffey of University College London and Prof Lyndon da Cruz, a retinal surgeon at Moorfields Eye Hospital.
They aimed to treat 10 people who had the “wet” form of AMD, caused by sudden leakage from blood vessels in the eye that can destroy the macula, a key part of the retina. The retinal pigment epithelial (RPE) cells in the macula are crucial to the functioning of the light sensitive photoreceptor cells, which die without RPE support.
The two patients, a woman in her 60s and man in his 80s, are the first in the UK to have the treatment, and were chosen because of their advanced disease – they would have gone blind within six weeks of the blood vessel leakage. Each had one eye implanted with the patch, which consisted of a membrane covered with human embryonic stem cells engineered to differentiate into RPE cells. The results are published in the journal Nature Biotechnology.
Coffey said the improvement in vision – often measured in lines on a reading chart – was much greater than they had hoped for: “We said we’d get three [out of the proposed 10] patients with vision recovery of three lines. They probably wouldn’t get reading vision back.
“The first patient has got six lines improvement, which is astounding, and the second has five lines and he seems to be getting better as the months go by. They are both really reading. At best [the woman] could read about one word a minute with magnification. She is now reading 80 words a minute and [the man] is reading 50.”
The male patient was Douglas Waters, 86, from Croydon. His case was severe and the doctors were not especially hopeful when they gave him the treatment in autumn 2015. But the results have been remarkable.
“In the months before the operation my sight was really poor and I couldn’t see anything out of my right eye,” he said. “I was struggling to see things clearly, even when up close.
“After the surgery my eyesight improved to the point where I can now read the newspaper and help my wife out with the gardening. It’s brilliant what the team have done and I feel so lucky to have been given my sight back.”
Coffey and da Cruz intend to operate on one more patient to ensure the safety of the procedure. One of the successes of the trial has been showing that there was no need for drugs to suppress the patient’s entire immune system to avoid rejection of the stem cells. The eye is self-contained, so they were able just to inject pellets that release immunosuppressant drugs into the eye over the course of two to three years.
Coffey thinks they can have an off-the-shelf treatment available for NHS surgeons to use within five years, at the moment just for the 10% of AMD patients with the wet form of AMD. Dry AMD develops more slowly and there is no treatment for it. Coffey says, however, that there is no reason why the patch would not work for them too.
In due course, the team hopes the treatment could become as common and eventually as cheap as cataract surgery.
Dr Carmel Toomes, associate professor at the Leeds Institute of Molecular Medicine, said: “These results give the many patients out there who suffer from AMD and other retinal degenerations real hope that stem cells replacement therapy may be a reality in the near future. While this is only a very early clinical trial, the results are positive and show that the technology is moving along. In the right direction.”
