Apr 21, 2023

Bionic Sight Reports Meaningful Vision Improvements for RP Patients Receiving Highest Dose of its Emerging Optogenetic Therapy

Eye On the Cure Research News

Clinical trial participants with advanced vision loss from RP were able to identify fruits and vegetables

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All 12 patients dosed thus far in a Phase 1/2 dose-escalation clinical trial for Bionic Sight’s emerging optogenetic treatment have demonstrated significant vision improvements. Those receiving the highest dose of the therapy had the most vision restored. The trial, which began in March 2020, is ongoing at Ophthalmic Consultants of Long Island.

The four top responders in the trial gained the ability to recognize shapes and objects. In one set of vision tests, patients were asked to identify images of shapes such as hearts, diamonds, clubs, and spades. In another test, they were asked to identify eight different kinds of fruits and vegetables. The success rate for recognizing the objects ranged from 80 to 100 percent for the four top responding patients. Prior to treatment, their success rate was much lower, equivalent to just guessing (25 percent correct when given four choices and 12.5 percent with eight choices).

“The tests are all videotaped, and one can see that these patients were clearly frustrated when performing the tests at baseline, prior to treatment. They often said aloud they couldn’t see the objects, much less recognize them, ” said Bill Seiple, PhD, an investigator on the Bionic Sight trial and the scientific director at the Lighthouse Guild. “For the four top responders, that frustration was replaced with exuberant outbursts of “banana!” or “I see the carrot!” It was joyous to watch.”

One patient said he saw the technician testing him, including the shape of their body and the movement of arms and hands, and he exclaimed that the person appeared like a superhero, “waving their arms, going off to fight the good fight.”

The four top responders also showed improvement in visual acuity as measured using the ETDRS chart (standard eye chart). Two patients went from not being able to see anything on an eye chart to correctly reading the second line.

“A particularly exciting and important aspect of the study is that the perceptual tests were corroborated by non-invasive brain recordings similar to EEGs,” said Sheila Nirenberg, PhD, founder of Bionic Sight. “Patients who showed strong improvement on the perceptual tests also showed a clear increase in neural activity in the visual cortex. Thus, two independent measures demonstrated efficacy.”

Bionic Sight’s approach involves two components:

1) A one-time optogenetic treatment that enables expression of a light sensitive protein in retinal ganglion cells which survive after photoreceptors are lost to an advanced retinal disease like RP.

2) A device, worn like a pair of glasses, that captures the scene a person is looking at and generates vision-enabling code, which is sent to the light-sensitive ganglion cells, and then on to the brain.

Unlike other emerging optogenetic approaches, which may use glasses or goggles to enhance the shape and intensity of the image, the Bionic Sight device produces neural impulses, similar to those produced by normal ganglion cells in the healthy retina. Dr. Nirenberg believes that utilizing the retina’s normal code can lead to better vision for patients.

Study investigators are evaluating vision restoration for participants receiving the optogenetic treatment with and without the code-delivering goggles. They believe the goggles will be most helpful to those patients who are at the most advanced stage of disease and have little retinal circuitry remaining.