Eye On the Cure Research News

May 24, 2021

Investigators Report Partial Vision Restoration for One Patient in Optogenetic Therapy Trial

The gene-agnostic approach is designed to restore some vision to people with advanced vision loss

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Investigators testing an experimental therapy developed by GenSight Biologics, a clinical-stage gene therapy development company, have reported that one patient with retinitis pigmentosa (RP) demonstrated partial vision restoration in the Phase 1/2 PIONEER clinical trial for its emerging optogenetic therapy. Results from the study were reported in the journal Nature Medicine. The Foundation Fighting Blindness funded preclinical research that led to the initiation of this important clinical trial.

GenSight’s treatment combines a light-sensing gene therapy (optogenetics) coupled with image-capturing eyewear, which enhances visual stimulation. The optogenetic therapy is designed to bestow light sensitivity to ganglion cells — retinal cells that are not normally light sensitive, but often survive after photoreceptors are lost. The eyewear transmits an amplified light image signal to further stimulate ganglion cells and enhance the user's visual experience.

Patient who entered trial

Patient who entered the trial with only light perception due to advanced RP (Usher syndrome type 2A).

The system is designed to restore vision for people who are blind from advanced RP and potentially other retinal conditions such as: Usher syndrome, Stargardt disease, and dry age-related macular degeneration. The GS030 system works independent of the gene mutation causing the retinal disease.

GenSight reported results for a 58-year-old man who entered the trial with only light perception due to advanced RP (Usher syndrome type 2A). After receiving the optogenetic therapy, the patient was able to locate and reach for objects on a table while wearing the image-capturing eyewear. Also, using electroencephalography, a technique that maps neural connections between the eye and the brain, the clinical researchers observed increased activity in the patient’s visual cortex while he was undergoing the tests to perceive objects.

As of the end of 2020, seven patients in the PIONEER dose-escalation trial had received the emerging optogenetic treatment. However, due to the COVID-19 pandemic, visual assessment was only performed on one patient. He received the lowest dose of the optogenetic treatment.

“We are encouraged by the initial report of partial vision restoration coming from GenSight’s trial for its optogenetic therapy and look forward to more data from additional patients,” says Ben Yerxa, PhD, chief executive officer at the Foundation Fighting Blindness. “Optogenetics is exciting for us because it provides a potential solution for people with the most advanced vision loss.”