French biopharma Gensight Biologics has published the first case report of gene therapy leading to the partial recovery of visual function in a blind patient with late-stage retinitis pigmentosa (RP).
Published in Nature Medicine, Gensight described the success of GS030 optogenetic therapy as part of its Pioneer phase 1/2 trial. Gensight’s therapy targets retinal ganglion cells unaffected by RP to express opsin ChrimsonR, rendering them light sensitive. The therapy is delivered using a viral vector via intravitreal injection (IVT). Around 4.5 months after IVT, the patient is trained with proprietary light-stimulating goggles (GS030-MD) which project modified ambient light onto the treated retina.
Prior to treatment, the patient was only able to perceive the absence or presence of light due to his RP, diagnosed 40 years prior. Following this treatment and training with the goggles in Streetlab (a simulated street setting with advanced visuospatial monitoring capabilities), visual function tests demonstrated that he had the ability to perceive, locate, count and even touch objects. The patient also reported significant improvements in domestic activities such as navigating outdoors and detecting household objects and furniture.
“It was breathtaking to witness the first recovery of some visual function in a blind patient,” said Dr Botond Roska, co-founder of Gensight. “We have worked on optogenetic therapy in the lab for 16 years and seeing the proof of concept in a patient is a unique experience.”
Researchers said that their patient received the lowest dose IVT but that the trial will move forward to include higher doses, enrolling a total of 12 to 18 subjects.
