University of Adelaide researchers have conducted the first human trial of a new type of treatment for the 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 do not work properly, resulting in progressive blindness. Current treatment options for later stages of the disease are limited and there is no cure.
Now, a new approach to treating the disease offers new hope. In collaboration with researchers from the University of Washington, University of Adelaide experts conducted a small pilot trial to see if a potential treatment based on a molecule could be safely tolerated in humans.
They found that when the small molecule was injected into the eye, it revived some of the damaged retinal cells, making them sensitive to light again. This happened even after the loss of normal light-sensing cells.
What originally started as a very small trial to test the drug’s safety has now opened up the possibility of a whole new way of treating degenerative eye diseases.”
Robert Casson, Professor and Principal Investigator, School of Medicine, University of Adelaide
“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 in many different forms of retinal degeneration.
“It also avoids the need for genetic modification, which simplifies treatment and can reduce risks.”
Several participants in the small trial reported short-term improvements in 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 side effects and no evidence of harmful effects on the eye.” said Professor Casson.
“We also saw early signs that the drug might have a biological effect – some participants reported changes in light perception, and brain imaging showed activity in visual areas of the brain after treatment.
“While this is certainly positive, it should also be emphasized that these are preliminary findings and need to be confirmed in larger studies.”
Kiora Pharmaceuticals provided industry support for the study and the findings were published in the journal, Nature Medicine.
A larger Phase 2 trial is currently underway to more rigorously evaluate whether this treatment can improve vision.
“More broadly, this work creates a new platform for vision restoration that could be further developed for retinal diseases beyond retinitis pigmentosa.” said Professor Casson.
