Kiora Pharmaceuticals has announced the receipt of regulatory approval to initiate ABACUS-2, a Phase 2 clinical trial evaluating KIO-301 for vision restoration in patients with retinitis pigmentosa. This study marks a significant step forward in addressing the unmet medical need for effective treatments for this inherited retinal disease, which affects approximately 1 in 4,000 people globally.
ABACUS-2 Trial Design
The ABACUS-2 trial is a multi-center, double-masked, randomized, controlled study that will enroll 36 patients with ultra-low vision or no light perception, regardless of their underlying gene mutation associated with retinitis pigmentosa. Conducted across five centers in Australia, the trial will randomize participants in a 2:1 ratio to receive either KIO-301 or a control treatment. Two dosage levels of KIO-301 (50 and 100 micrograms) will be administered intravitreally every six weeks. Following three consecutive doses, patients will be followed for three months. Patients in the control arm may then elect to cross over into the active arm.
KIO-301: A Novel Photoswitch Molecule
KIO-301 is a small molecule designed to act as a light-sensitive photoswitch. It targets retinal ganglion cells (RGCs), specialized cells in the retina located downstream of degenerated rods and cones. By entering RGCs and being activated by visible light, KIO-301 confers light-sensing capabilities, potentially restoring vision in patients with inherited retinal diseases. This mechanism of action is particularly compelling because it has the potential to work across all 150-plus underlying gene mutations associated with retinitis pigmentosa and other inherited retinal diseases.
Endpoints and Regulatory Strategy
The primary endpoints of the ABACUS-2 trial are safety and tolerability. Key efficacy assessments include functional vision, visual acuity (measured by the Berkeley Rudimentary Vision Test), visual fields (measured by perimetry), and a validated ultra-low vision quality-of-life questionnaire. Kiora has engaged with European and U.S. regulators to incorporate their expectations and guidance for approvable endpoints, emphasizing the need to measure a therapy's effect on everyday functional vision. Successful validation of these functional endpoints could potentially lead to a single Phase 3 trial strategy for market approval in the U.S. and Europe.
Collaboration and Future Outlook
This clinical trial is being advanced in partnership with Théa Open Innovation. Dosing of the first patient with KIO-301 is expected to begin next year, pending validation of the novel functional vision endpoints. The partnership with Théa Open Innovation provides important validation and support for the development program.
