Kiora Pharmaceuticals Reports New Data Showing Increased Brain Activity in Retinitis Pigmentosa Patients

Kiora Pharmaceuticals, Inc. recently shared additional data from their ABACUS-1 clinical trial for KIO-301, a small molecule photoswitch aimed at improving vision in patients with late-stage retinitis pigmentosa. The new findings highlight a significant increase in brain activity in the visual cortex as measured by functional MRI (fMRI), confirming the drug's potential in enhancing visual processing.

The ABACUS-1 trial, a Phase I/II study, demonstrated KIO-301’s capability to increase visual cortex activity relative to baseline, as shown through fMRI. This standard method measures changes in the visual cortex by assessing voxel activity, the three-dimensional equivalent of a pixel. KIO-301 is designed to provide light sensitivity to retinal cells that can still transmit neural signals to the brain after the natural photoreceptors (rods and cones) have degenerated.

The results were presented by Professor Robert James Casson, Head of the Ophthalmic Research Lab at The University of Adelaide, during the Association for Research in Vision and Ophthalmology (ARVO) annual meeting in Seattle. Key findings included statistically significant increases in visual cortex activity from baseline at all measured time points. This rise in activity was observed across different patient cohorts, including those with varying levels of baseline vision. Patients with better initial vision showed a more pronounced increase in visual cortex activity. This increase was time-dependent and paralleled improvements in visual acuity, visual field, and functional vision.

Professor Casson underscored the importance of these findings in supporting the potential of KIO-301 to restore meaningful vision. The fMRI data helps elucidate the connection between observed functional outcomes and the drug’s mechanism of action. Eric Daniels, Chief Development Officer of Kiora, highlighted that the fMRI results are consistent with functional improvements in patients' daily activities, a critical factor for drug approval.

KIO-301 functions as a small molecule photoswitch, selectively providing light-sensing capabilities to retinal ganglion cells (RGCs). In healthy eyes, rods and cones first convert light to electrical signals, which are then transmitted through RGCs to the brain's visual cortex. However, in inherited retinal diseases (IRDs) like retinitis pigmentosa, genetic mutations lead to the degeneration of photoreceptors. Despite this, RGCs remain viable and can be targeted to bypass the lost photoreceptors. KIO-301 enters these RGCs, turning "on" in the presence of light to signal the brain and "off" in its absence, effectively acting as a light switch within the eye.

In January 2024, Kiora partnered with Théa Open Innovation for the co-development and commercialization of KIO-301. They are planning a Phase II multi-center, randomized, controlled clinical trial (ABACUS-2).

Retinitis pigmentosa (RP) is a hereditary disorder characterized by the degeneration of retinal photoreceptors, leading to progressive vision loss. Affecting approximately 1 in 4,000 individuals globally and around 100,000 in the United States, RP often results in legal blindness by middle age. Kiora aims to address this unmet need with KIO-301, which could serve as a standalone therapy or be used in conjunction with future gene therapies.

Kiora Pharmaceuticals is at the forefront of developing treatments for orphan retinal diseases. In addition to KIO-301, which targets retinitis pigmentosa, choroideremia, and Stargardt disease, Kiora is also developing KIO-104 for posterior non-infectious uveitis. Kiora's innovative approach aims to improve visual function in patients with inherited and age-related retinal degeneration.