Kiora Pharmaceuticals, Inc. revealed preliminary results from its ongoing phase 1b study assessing KIO-301 for the potential treatment in restoring light perception in patients with vision loss due to retinitis pigmentosa (RP).
Refresh me on KIO-301
KIO-301 is a visible light-sensitive small molecule (called a “molecular photoswitch”) designed as a reversible photoswitch to restore the eye’s ability to perceive and interpret light in visually impaired RP patients via intravitreal injection.
It works by specifically entering photoreceptors’ key downstream retinal cells (bipolar and retinal ganglion cells [RGCs])) and turning them into light-sensing cells capable of notifying the brain of the presence / absence of light.
Talk about this trial.
The ABACUS study—an open-label, dose-escalating phase 1/2 study (NCT05282953)—enrolled 6 patients (ages 18 to 80 years; 12 eyes total) with RP.
Participants were evenly split into two cohorts: the first included patients with no or bare light perception; the second included patients who were able to detect hand motions and count fingers.
Patients were assessed during five visits on Day 1-3, Day 7-8, Day 14-15, and Day 29-30 for the first cohort.
What were the dosage levels?
Cohort 1 included two KIO-301 doses of 7.5 µg and 25 µg (contralateral eye), while Cohort 2 included one dose of 25 µg in one eye and 50 µg in the fellow eye..
Of note, each cohort will be assessed over the same period throughout the study (Cohort 1 [7.5 µg dose initial eye]: Day 1-30; Cohort 2 [25 µg dose initial eye]: Day 31-60; Cohort 1 [25 µg dose contralateral eye]: Day 61-90; Cohort 2 [50 µg dose contralateral eye]: Day 91-120).
How about some findings?
Kiora presented preliminary case study data from a patient with no light perception who received a low dose of K10-301 in one eye.
Highlights included improvement in identifying objects and perceiving the contrast between light and dark (Days 7 and 29); a 6-point, clinically meaningful increase in quality of life (QoL); and a positive impact on overall, everyday functional vision.
What else?
Through functional MRI, imaging data revealed significantly increased activities in brain areas (visual cortex) at Days 3 and 15 after injection (compared to baseline).
Any adverse effects?
The company reported no adverse events (AEs) throughout the study; the initial dose was observed to be safe and well-tolerated (Day 29).
Expert input?
"We saw a marked improvement in functional measures, which correlate to neural imaging results that demonstrate increased visual cortex activity in the brain from baseline to two weeks after treatment,” stated Robert Casson, MBBS (Hons), M. Biostatistics, DPhil, FRANZCO, the study’s principal investigator.
Significance?
Casson added that the preliminary study data suggests the initial low dose of KIO-301 is capable of improving light perception in patients who have ultra-low vision or blindness.
What’s next?
Now we wait. The company expects to report full data findings from the study by Q4 2023.