RetroSense Therapeutics has reported that three participants have received injections of its potential optogenetic therapy, known as RST-01, in a Phase I/II clinical trial. The patients were given the lowest dose of RST-01, and no adverse ocular events were observed. Furthermore, the treatment showed some biological activity, though RetroSense did not provide details about what that activity was or what it meant.
More information on safety and efficacy will likely be reported about the RetroSense trial after more trial participants have been observed over a longer period of time, and after discussions with the U.S. Food and Drug Administration.
RetroSense’s optogenetic therapy is designed to restore vision to people who are completely blind from retinal degenerative diseases such as retinitis pigmentosa by bestowing light sensitivity to retinal ganglion cells, which survive after photoreceptors, the cells that make vision possible, are lost. Retinal ganglion cells normally don’t process light; rather, they perform image-processing functions downstream.
RetroSense’s treatment is a gene therapy, which uses a human-engineered adeno-associated virus (AAV) to deliver a gene to retinal ganglion cells that encodes channelrhodpsin-2, a light-sensing protein.
A benefit of the therapy is that it has the potential to work regardless of the gene mutation causing the patients’ vision loss.
The company plans to inject the treatment into what they call the “mid-dose” cohort within the next month. Dose escalation is a common practice in early clinical trials focused on safety. If no adverse events are observed at a lower dose level, the treatment developers will increase the dose, hoping they will observe efficacy (i.e., changes in vision).
RetroSense’s clinical trial is taking place at the Retina Foundation of the Southwest and is the first-ever for an optogenetic treatment.
The Foundation Fighting Blindness provided early funding for the development of RetroSense’s treatment and participated in discussions about the clinical trial with the U.S. Food and Drug Administration.