A blind, 58-year-old male patient with retinitis pigmentosa experienced partial recovery of vision after a novel optogenetic treatment.
A blind patient with retinitis pigmentosa has had his vision partially restored in the PIONEER clinical trial. Image credit: Pexels.
Retinitis pigmentosa is a progressive, inherited neurodegenerative eye disease where loss of photoreceptors can lead to complete blindness.
It affects more than 2 million people worldwide and is caused by mutations in more than 71 different genes.
With the exception of a gene replacement therapy for one form of early-onset retinitis pigmentosa caused by mutation in a gene called RPE65, there is no approved therapy for retinitis pigmentosa.
“Optogenetic vision restoration is a mutation-independent approach for restoring visual function at the late stages of retinitis pigmentosa after vision is lost,” said Sorbonne Université’s Dr. José-Alain Sahel and colleagues.
“The open-label phase 1/2a PIONEER study was designed to evaluate the safety and efficacy of an investigational treatment for patients with advanced nonsyndromic retinitis pigmentosa that combines injection of an optogenetic vector with wearing a medical device, namely light-stimulating goggles.”
The researchers injected an adeno-associated viral vector encoding the optogenetic sensor ChrimsonR into one eye of the patient with retinitis pigmentosa, combined with light stimulation via light-stimulating goggles.
The goggles had a special camera that captured images from the visual world and transformed them into light pulses that were then projected onto the retina in real time in order to activate the modified cells during visual tasks.
This treatment approach was well tolerated, and the previously blind patient was able to recognize, count, locate and touch different objects with the treated eye while wearing the light-stimulating goggles.
The scientists concluded that optogenetic therapy may be beneficial in restoring visual function in people with retinitis pigmentosa-related blindness.
However, further results from the PIONEER trial are needed for a clearer picture of the safety and efficacy of this approach.
“Taken together, the psychophysical and neurophysiological evidence presented in our article suggest that the optogenetic stimulation of human retinal ganglion cells by a light-projection system linked to a camera is a promising way to partially restore vision in blind patients affected with advanced retinitis pigmentosa,” the authors said.
Their paper was published online in the journal Nature Medicine.
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J.-A. Sahel et al. Partial recovery of visual function in a blind patient after optogenetic therapy. Nat Med, published online May 24, 2021; doi: 10.1038/s41591-021-01351-4
