A French biopharma company has announced their plans to carry out human trials of a new treatment that would insert genes from light-seeking algae into the eyes of patients with inherited blindness in order to help them regain sight. The treatment involves optogenetics, a technique that converts nerve cells into light sensitive cells. Although optogenetics is commonly used in animal experiments, its effects on humans are far less known.
Recently, GenSight Biologics announced that the UK Medicines and Healthcare Regulatory Agency accepted the company’s clinical trial application to start Pioneer Phase I/II. The trial, expected to begin on UK patients in the first quarter of 2018, plans to study gene therapy as a treatment for patients with the genetic condition of retinitis pigmentosa, the press release announced.
Retinitis pigmentosa is an inherited condition that damages photoreceptor cells, or cells that convert light into electrical signals. As a result, this slowly changes the way the retina reacts to light and makes it progressively more difficult for patients to see. Eventually patients become completely blind. In order to be eligible for the trial, candidates must not yet be completely blind and at least have the ability to see five fingers held up from about a foot and a half away. At first the gene will only be injected into one eye.
A combination of both optics and genetics, optogenetics involves inserting a light sensitive gene into neuronal cells, cells in the brain, spinal cord, or in this case, the eye. The gene is actually derived from single-celled algae and helps the algae detect light.
Normally optogenetics is used in animals to help researchers better understand how the brain works as it allows them to illuminate certain areas of the brain and document brain behavior. However, in this trial, the doctors hope that the gene will convert ganglion cells, which normally communicate information from the eye to the brain, into photoreceptor cells. By recruiting cells to replace those damaged by retinitis pigmentosa, scientists believe they can restore vision. At the moment it’s unclear just how successful the treatment will be, but experts are hopeful.
“This therapy is novel in its approach,” Dr. Anne Negrin, an ophthalmologist in Purchase, New York who is affiliated with Greenwich Hospital and not involved in the trial or research told Newsweek. “This is the first time we are trying to give vision to people with degenerative eye disease by recruiting ganglion cells to receive light signals to the brain, rather than trying to repair already damaged photoreceptor cells.”
The gene will be injected into one eye and the hope is that it will only boost the detection of red light. Patients will then use a special goggles to help them improve their overall vision. According to the organization, Color Blind Awareness, photoreceptors in our eyes normally perceive three types of light, red, green and blue. However, the new photoreceptors created in this project can only perceive red light. That means the eye will not be able to interpret color and the patients will only be able to see in black and white.
The primary analysis is meant to test the safety of the treatment over the course of a year.
Source: New Scientist