Sight restoring treatment hits a nerve

The “dramatic recovery in vision” in mice suffering retinitis pigmentosa (RP) – which were given a virus to make their retinal nerve cells light sensitive – has sparked a US clinical ophthalmology company’s interest.

Acucela Inc, of Seattle, has licenced the gene therapy developed by the University of Manchester. This week, Acucela announced its plans to develop and commercialise the technology targeting the rare and incurable condition with the university.

The gene therapy uses a specially designed virus to insert the DNA instructions for the rhodopsin light-sensing protein into neurons in the inner nuclear layer of the retina, which remain after the photoreceptors have degenerated.

Based on the animal trials by Manchester researchers Professor Paul Bishop, Professor Robert Lucas and Dr Jasmina Cehajic-Kapetanovic, these cells are then able to successfully pick up light and transmit signals to the brain, returning some form of sight.

However, the University of Manchester are not the only group to take this approach to treat RP. A human clinical trial is currently using a virus to introduce DNA for a light-sensitive algal protein into the ganglion cells in the eyes of RP patients.

However, the University of Manchester researchers are confident that using rhodopsin, rather than a protein from another species, will be less likely to produce an immune system response. Another benefit of this protein is that it is highly sensitive to light.

Professor Bishop told OT that the partnership was an exciting step forward for him personally.

“I see patients with very poor vision from RP regularly in my clinics. It would be very exciting to be able to offer them the prospect of a treatment that will improve their vision,” he explained.

Acucela chairman, Dr Ryo Kubota, said the ultimate goal was to improve the lives of patients who “had lost much of their vision as well as their hope.”

The gene therapy will also be tested for its effectiveness in other degenerative eye conditions.

It is hoped that the first human patients will be treated with the gene therapy within three years.