Gene Therapy Built on This Year’s Medicine Nobel Partly Restores Sight

Two days after the Nobel Prize in Physiology or Medicine went to the scientists behind optogenetics, researchers have reported that a gene therapy based on the technique is safe and can partly restore vision in people who have lost their sight to an inherited eye disease.

The prize, announced Monday at the Karolinska Institute in Stockholm, was shared by Karl Deisseroth of Stanford University, Peter Hegemann of Humboldt University in Berlin and Georg Nagel of the University of Würzburg for their discoveries about light-sensitive ion channels. Their work gave scientists a way to switch individual nerve cells on and off with light, and the Nobel committee said the method is now used in laboratories around the world to study the brain.

The new study, published in the New England Journal of Medicine and described by the Guardian, followed 10 people with advanced retinitis pigmentosa, a group of genetic disorders estimated to affect more than 1.5 million people worldwide. In these conditions the retina’s light-detecting cells gradually fail, but the ganglion cells that carry signals to the brain tend to survive longer.

Each participant received a single injection into the worse eye. It carried a harmless engineered virus that delivered instructions for making a light-sensitive protein into surviving ganglion cells. Patients then wore goggles that capture the scene in front of them and convert it into pulses of light of a single wavelength, which activate the treated cells and let the wearer perceive a monochrome image. Because the approach bypasses the damaged cells, it does not depend on which gene caused a patient’s sight loss.

Participants were followed for up to five years, the Guardian reported. Six of the 10 had clinically meaningful gains in light sensitivity, and four of the eight who completed behavioral testing improved on tasks such as detecting, locating or touching objects while wearing the goggles, according to GenSight Biologics, which developed the therapy. The Guardian’s account described tasks such as finding and touching a notebook, locating a door and walking along a line, and said those who trained more with the goggles tended to do better. Only one serious eye-related side effect occurred, and it resolved within minutes; the researchers reported no therapy-related side effects elsewhere in the body.

The results build on a 2021 report of partial vision restoration in a single patient, the Guardian noted. Botond Roska of the Institute of Molecular and Clinical Ophthalmology Basel, a lead author, said, according to the Guardian, that the trial confirms that the concept works for vision and that the team hopes to restore high-resolution sight within five to 10 years. For now, he said, patients can detect objects but not faces, because the treated cells sit in a ring around the center of the retina that handles sharp vision.

The caution is warranted. Ten patients is a small number, the gains are modest, and the therapy requires both surgery and specialized equipment. Mark Hankins, a visual neuroscientist at the University of Oxford who was not involved, called the results, according to the Guardian, baby steps but critical ones, noting the durable improvement over four to five years.