ProQR Tackles Blindness Caused by a Rare Genetic Disease

blindness deafness usher syndrome proqr2 1

ProQR has received €6M from the American charity, Foundation Fighting Blindness, for the development of its treatment for Usher Syndrome – the leading cause of combined blindness and deafness.

ProQR focuses on the development of RNA-based medicines for genetic diseases like cystic fibrosis. However, it is the company’s program targeting Usher syndrome, the leading cause of combined deafness and blindness, that has caught the attention of the US-based charity, Foundation Fighting Blindness. The two have come together to develop ProQR’s candidate, QR-421a, which targets blindness caused by the condition. The charity will provide $7.5M (€6M) to support its preclinical and clinical development and ProQR hopes to enter the clinic in 2018 and share results of a Phase I/II trial in 2019.

Usher syndrome is a rare disease, affecting just 4 in every 100,000 children in the US. However, it has devastating symptoms, including hearing loss and the development of retinitis pigmentosa, a genetic disease of the eye characterized by the loss of photoreceptor cells in the retina. ProQR’s drug is being developed for type 2A of the disease, one of the most common forms, which is caused by a mutation in the USH2A gene. With no approved treatments for the condition and nothing in the clinic, there is a desperate need for research in this area.

ProQR’s candidate, QR-421a, has been designed to correct the mutation in exon 13 of the USH2A gene, which causes the loss of an important usherin protein. QR-421a repairs the genetic defect in the eye’s RNA so that a smaller but functional usherin protein is produced. Unlike gene therapy, this approach will not require permanent changes to be made to the genome. The potential of the treatment has been highlighted by the FDA awarding it with Orphan Drug Designation.

Usher syndrome type 2a is caused by a mutation in the gene encoding a protein called usherin, which forms an important part of the basement membrane in the retina and inner ear.

Blindness is understandably an area that receives a lot of attention from biotechs due to the distress that it causes patients. Luckily, biotechs are on the warpath, developing treatments for the diseases that cause it. Gene therapy is a common approach to the treatment of retinitis pigmentosa as the eye is an immune-privileged site. Horama is targeting mutations in the PDE6β gene, while NightstaRx focuses on RPGR gene mutants. GenSight has gone a step further and combined its gene therapy with a wearable device that can treat up to 100 disease-causing mutations.

When Clara interviewed Auris CEO, Thomas Meyer, he pointed out that “there are no specific inner ear therapeutics on the market,” which explains why his company is getting busy in the hearing loss field. Unfortunately, the biotech’s Phase III results didn’t go to plan, with its lead candidate missing its efficacy endpoint. Elsewhere, Sensorion is working with Cochlear, the world’s leading hearing implant company, to develop drug and implant combinations for the treatment of hearing loss.

It is good to see a less well-known condition, which not only affects our sight but also our hearing, getting attention from a big name in biotech like ProQR. Perhaps there is potential for all of these companies to share their ideas, which could help us see treatments for a range of conditions affecting our eyes and ears reach the market sooner.

Images – ananaline /; / 

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