Kiora reports vision restoration in phase 1/2 clinical trial for photoswitch therapy  

Kiora Pharmaceuticals has announced partial vision restoration for participants in ABACUS-1, its Phase 1/2 clinical trial in Australia for KIO-301, a molecule designed to restore light sensitivity to retinal ganglion cells, neurons that connect retinal input to the central nervous system, in people with advanced retinitis pigmentosa (RP) and other retinal diseases. Results for six patients in the study were presented 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. Retinal ganglion cells, which are downstream from photoreceptors, often survive in advanced retinal disease but do not naturally respond to light. Known as a photoswitch, the molecule enables retinal ganglion cells to respond to light, thereby working like a back-up system for lost photoreceptors. 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. Functional MRI showed an increase in visual cortex activity for patients in the trial.

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. Control group patients will go on to receive active drugs in an open-label extension (long-term study). 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.

For more information on this trial, visit or contact Eric Daniels, M.D., MBA at 61 448787315 or Note that this study is being conducted in Australia.

Edited by Suditi Kedambadi, Vista Center Health Library volunteer

Source: Foundation Fighting Blindness, Eye On the Cure Research News, November 8, 2023; see source article