Scientists in the UK have successfully used gene therapy to restore some vision to legally blind children with an inherited retinal condition. All 11 children in the clinical trial saw improvements within weeks of a single surgical treatment.
The children were all born with a form of severe retinal dystrophy called LCA4, leaving them with only a limited ability to perceive light. This form of the disease is caused by mutations in the AIPL1 gene, which results in deficiencies of the protein of the same name. This protein plays a key role in converting light into electrical signals that the brain can interpret.
In the study, the children received a gene therapy targeting AIPL1 delivered directly into their retina. Four weeks after their treatment, their vision was evaluated using a range of tests, including following a pen light, moving crayons between cups, locating white objects on a dark background, and navigating a corridor. Retinal structure and brain activity in response to light was also measured.
And sure enough, all 11 children treated so far have seen “meaningful responses” to the therapy. They were all between one and four years old at time of treatment, and their progress has been followed for three to four years since.
The first four children received the treatment in one eye, and the tests were conducted in both the treated and untreated eyes independently. By the end of the study period, the untreated eyes of all four children showed no perception of light or were unmeasurable. The treated eyes had advanced from legally blind to low vision.
A second cohort of seven children has also received the gene therapy, this time in both eyes. Their trial is still ongoing, but the early results look just as promising, the team says.
“The improvements demonstrated are unrivaled in treatment benefit compared to any ocular gene therapy in any inherited retinal disease,” said Dr. Alexandria Forbes, president and chief executive officer of MeiraGTx, the genetic medicine company developing the therapy. “These improvements extended outside the meaningful effects on vision and result in life-changing benefits in all areas of development including communication, behavior, schooling, mood, psychological benefits and social integration.”
While these studies continue, the gene therapy has been granted orphan drug designation by the US FDA and the European Commission, as well as rare pediatric disease designation (RPDD) by the FDA. Gene therapies targeting other forms of retinal dystrophy have also been granted FDA approval, raising hopes for wider use.
The data from the first cohort of four children has been published in the journal The Lancet. Some of the tests, with drastic improvements between the treated and untreated eyes, can be seen in the video below.
Source: MeiraGTx
