Adelaide University researchers have carried out the first in-human trial of a new type of treatment for a leading cause of blindness in working age adults, with promising results.
Retinitis pigmentosa is a genetic condition where the retinal cells responsible for detecting light don’t work properly, resulting in progressive blindness.
Current treatment options for later stages of the disease are limited and there’s no cure.
Now, a new approach to treating the disease is providing fresh hope. Working with researchers from the University of Washington, Adelaide University experts carried out a small pilot trial to see if a potential therapy based on a molecule could be tolerated safely by humans.
They found when the small molecule was injected into the eye, it revived some of the damaged retina cells, making them sensitive to light again. This happened even after the normal light-sensing cells had been lost.
“What originally started as a very small trial to test the safety of the drug has now opened up the possibility of a completely new way of treating degenerative eye diseases,” said Principal Investigator, Professor Robert Casson from Adelaide University’s School of Medicine.
“This is the first clinical trial of a photoswitch drug in humans. Unlike gene therapies, which target specific mutations, this approach could potentially be used across many different forms of retinal degeneration.
“It also avoids the need for genetic modification, which simplifies treatment and may reduce risks.”
Several participants involved in the small trial reported short-term improvements to their ability to perform visual tests, including walking tasks. One participant with severely damaged retinal cells reported greater awareness of light perception within two days of receiving the treatment.
“We found that the treatment was well tolerated, with no serious adverse events and no evidence of harmful effects on the eye,” said Professor Casson.
“We also saw early signals suggesting the drug may be having a biological effect—some participants reported changes in light perception, and brain imaging showed activity in visual areas of the brain following treatment.
“While this is certainly positive, it must also be stressed that these are preliminary findings and need to be confirmed in larger studies.”
Kiora Pharmaceuticals provided industry support for the study and the findings have been published in the journal, Nature Medicine.
A larger Phase 2 trial is currently underway to more rigorously assess whether this treatment can improve vision.
“More broadly, this work establishes a new platform for vision restoration that could be developed further for retinal diseases beyond retinitis pigmentosa,” said Professor Casson.
