Light sensing small molecule given green light for clinical testing in Australia
In contrast to gene and cell therapies, small molecules are the most common types of treatments approved throughout the world, and include typical household medicines like aspirin and antihistamines. However, KIO-301 is a novel type of small molecule known as a “molecular photoswitch” because it has the ability to rapidly and reversibly change shape in the presence or absence of light.
KIO-301 targets retinal ganglion cells (RGC), which, in the healthy eye, relay image signals from photoreceptors to the optic nerve. In advanced RP and other retinal conditions, the photoreceptors are no longer working and very little image signalling is going to the brain, despite the RGC themselves being unaffected by the disease.
By sitting in the retinal ganglion cells and changing shape in the presence of light, KIO-301 can activate the cells, effectively making them light-sensitive in their own right and resulting in some image information being sent to the brain. Kiora Pharmaceuticals hope that this has the potential to restore some functional vision to those with very advanced sight loss.
This strategy bears many similarities to optogenetics. However, whereas optogenetics is a one-time gene therapy approach, KIO-301 will be administered once a month via injection into the vitreous (jelly) of the eyeball. This means it can be given in outpatient clinics and potentially makes it more flexible and adjustable than optogenetics.