Age-related macular degeneration (AMD) is the most common cause of vision loss in people over the age of 50 and affects millions of people worldwide. The common degenerative disease begins with disruptions in a person’s central field of vision, and while it doesn’t always result in complete vision loss, it can profoundly alter one’s ability to undertake simple things such as reading or even recognizing faces.
In AMD, retinal cells are progressively destroyed by an aggressive immune response. This immune response has been found to be triggered by an overactive protein system.
Gyroscope Therapeutics, a UK-based company in collaboration with the University of Oxford have performed the first gene therapy operation aimed at stopping the progression of the most common cause of vision loss. The procedure can potentially deliver a gene that codes for a protein that essentially deactivates this aggressive immune response
However, scientists are yet to determine the success of the procedure. But, they do suggest that this one-off operation could be performed early in the degeneration process and essentially halt the disease in its tracks.
Robert MacLaren, an ophthalmologist from the University of Oxford working on the project said, “We’re harnessing the power of the virus, a naturally occurring organism, to deliver the DNA into the patient’s cells. 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, correcting the imbalance of the inflammation caused by the complement system.”
For this method, scientists used a benign virus to transport the new gene to where it needs to go. It also involves surgically detaching the retina and directly delivering the viral solution to the back of the eye. This targeted approach ensures the treatment is contained to a single point, while the virus is also engineered to only infect specific retinal cells.
The first person to undergo the procedure was Mrs. Janet Osborne of Oxford. Like many people with AMD, she has the condition in both eyes, but it is more advanced in her left eye. As is typical with this condition, the central vision in her left eye has deteriorated and is very hazy, although her peripheral vision is better.
The 80-year-old says that her restricted vision makes household tasks like preparing vegetables and sewing difficult, and she cannot read for very long. Often she finds it hard to recognize faces.
She says her motivation for taking part in the trial was the possibility of helping others with AMD: ‘I wasn’t thinking of me. I was thinking of other people. For me, I hope my site doesn’t get any worse. That would be fantastic. It means I wouldn’t be such a nuisance to my family.’
Though further clinical trials are required to test how safe the treatment is, and it will take some time before it is clearly proven to be effective. However, the scientists behind this incredible innovation are hopeful this one-off gene therapy procedure could be administered at the early stages of AMD, stopping the disease before it begins to permanently damage the eye, and potentially saving the sight of millions of people around the world.
Professor MacLaren said: “This is a rapidly evolving field. Given that we understand a lot more now about the manufacture of the treatment, and the effects of the virus when doing gene therapy at the back of the eye, as well as all the other gene therapy programmes being developed at the moment, I would hope that we’ll see a treatment for people with dry AMD within the next few years.”