As reported in Biospace, a new gene therapy has made notable progress towards curing x-linked retinitis pigmentosa, a disease responsible for sight loss in men. Until now, the disease irreversibly blinds patients. However, the progress in the study gives hope that patients may eventually be able to see another day.
X-linked Retinitis Pigmentosa
Retinitis pigmentosa is a rare genetic disease that progressively takes patients’ vision, beginning with night-blindness that often progresses until complete blindness. The disease is linked to the X chromosome, meaning it affects men almost exclusively, often during childhood or young adulthood. A mutation on the RPGR gene inhibits the ability for the cells to produce a protein that is necessary for the photoreceptor cells to function properly in the retina. There is currently no specific treatment option.
The Gene Therapy
The new international study was carried out on 18 patients who entered a six month trial, as researchers used a dose escalation to target the RPGR gene mutation. This specific mutation is responsible for about 70% of the disease cases. Dr. Janet L. Davis, a co-author of the study, said:
“The results from this initial trial showed no significant safety concerns after gene therapy surgery. Visual field improvements were observed in some patients, and these favorable findings support Bascom Palmer’s wide-ranging gene therapy research.”
These promising results allow the therapy to continue onto a randomized phase II/III trial, with the new trial using an optimized dosage that was found using results from from the first stage.
Some of the first available gene therapies have been used to restore vision, including some carried out by the Bascom Palmer Eye Institute, which was also involved in this trial. The team is well versed in the field of eye based technology, already receiving one of the first FDA approvals on a gene therapy for their work to treat choroideremia, another disease that causes progressive blindness.
Dr. Ninel Gregori, a co-author of the study said:
“It’s very exciting to see the impact our gene therapy surgeries can make in the quality of vision of our patients.”