A small but closely watched clinical trial has tested a new approach to partially restoring light perception in some participants with an advanced form of inherited blindness, with full results now published in the New England Journal of Medicine.
The PIONEER study enrolled 10 participants who had lost their sight due to advanced retinitis pigmentosa (RP) — an inherited condition where the light-sensing cells at the back of the eye gradually break down over time. Researchers evaluated the safety of a technique called optogenetic therapy, which works by introducing light-sensitive proteins into surviving cells in the retina so they can take over some of the signalling that the damaged cells can no longer do. The treatment, known as GS030, combines a gene-therapy injection into the eye with specially designed wearable goggles that deliver the light stimulation needed to activate the modified cells — the goggles are an integral part of how the therapy works.
The therapy targets ganglion cells — a layer of nerve cells in the eye that normally relay signals from the retina to the brain. In people with advanced RP, the original photoreceptor cells (the rods and cones) have already been lost, but these ganglion cells often survive. The idea is to make those remaining cells respond directly to light.
The New England Journal of Medicine published the full study results alongside a companion piece explaining the science of optogenetics and how it applies to vision research. The PIONEER trial was primarily designed to assess safety — a standard first step when testing any new therapy in humans — though visual-function assessments, including light-sensitivity testing, were also conducted as exploratory endpoints. Notably, six of the ten participants showed clinically meaningful improvement in those tests.
Ten participants is a very small group. But in early-phase trials like this, that’s by design — researchers need to establish that a treatment doesn’t cause harm before testing it in larger numbers.
Retinitis pigmentosa affects around 1 in 4,000 people in the UK, according to the NHS, and there are currently very few treatment options for those in the advanced stages of the condition. Optogenetic approaches have been in development for several years across different research groups internationally.
Anyone concerned about changes to their vision should contact their GP or call NHS 111. People already diagnosed with a retinal condition can ask their ophthalmologist (eye specialist) about current clinical trials and treatment options.
Source: @NEJM