Kiora Reports Vision Restoration in Phase 1/2 Clinical Trial for Photoswitch Therapy

Kiora Pharmaceuticals has announced some vision restoration for participants in ABACUS-1, its Phase 1/2 clinical trial in Australia for KIO-301, a molecule designed to bestow light sensitivity to retinal ganglion cells in people with advanced retinitis pigmentosa (RP) and other retinal diseases. Results for six patients in the study were presented at a late-breaking presentation on November 4 at the American Academy of Ophthalmology annual conference (AAO 2023) during the Retina Subspecialty Day by Russell N. Van Gelder, MD, PhD, professor and chair, Department of Ophthalmology, University of Washington, School of Medicine.

KIO-301 was initially tested in people who have lost all or most of their photoreceptors, the retinal cells that make vision possible, to an advanced retinal disease. Known as a photoswitch, the molecule enables retinal ganglion cells to respond to light, thereby working like a back-up system for lost photoreceptors. Retinal ganglion cells, which are downstream from photoreceptors, often survive in advanced retinal disease but don’t naturally respond to light. KIO-301 is delivered by a standard injection into the vitreous, the soft gel in the middle of the eye. One administration of the therapy appears to be effective for about a month.

The six patients in ABACUS-1 were split into two groups of three. Cohort 1 patients had no light perception or bare light perception. Cohort 2 patients had enough vision to see hand motion or count fingers. Three doses of KIO-301 were evaluated.

Cohort 1 patients appeared to have improvements in their ability to perceive the direction of movement and/or location of a window or lighted exit.

Cohort 2 patients had improvements in visual fields (peripheral vision) as measured by a Goldmann perimeter. Cohort 2 patients receiving the high dose had improvements in visual acuity, as measured by a Berkeley Rudimentary Vision Test, a test designed to evaluate vision in people without enough vision to read any letters on a typical eye chart.

Functional MRI showed an increase in visual cortex activity for patients in the trial.

Eric Daniels, MD, Kiora’s chief development officer, noted that it is important not to come to any major conclusions about the drug at this early juncture, though the evaluation results “point in the right direction.”

“This drug appears to be safe and it may support re-animation of the retina,” said Dr. Daniels. “It merits further study, in this case, a controlled randomized study to further tease out the signal over randomness.”

Kiora is planning the Phase 2 Abacus-2 study at three sites in Australia. Twenty patients will be   enrolled. Patients will receive monthly injections for three months. The study will be:  controlled, double-masked (patients and treating doctors won’t know if they are getting treatment or control), and randomized (patients will be randomly assigned to control or treatment group). Control patients will go on to receive active drug in an open-label extension.

Kiora is planning to share trial data with the US Food & Drug Administration. The company hopes to expand the study to the US and EU.

The company is exploring the enrollment of patients with choroideremia and Stargardt disease in a future clinical trial.

The Foundation Fighting Blindness provided $1.3 million in funding through its Translational Research Acceleration Program and a Gund Harrington Scholar Award to Richard Kramer, PhD, University of California, Berkeley, for the development of related photoswitches for restoring vision.