Inherited Retinal Diseases (IRD): Potential new drugs for retinitis pigmentosa and Usher syndrome
We most often think of inherited retinal diseases and dystrophies (IRD) as being incurable and rapidly leading to blindness. This may not remain the case for ever as research makes advances in gene therapy. Inherited retinal diseases include Retinitis Pigmentosa, Stargardt disease, the cone dystrophies, Leber Congenital Amaurosis (LCA) , Achromatopsia, Usher’s syndrome and many more.
The pharmaceutical and research company called ProQR Therapeutics has announced a drug in development called QRX-411 which is currently at the Orphan Drug Designation stage by the FDA and European Medicines Agency (EMA) for the treatment of retinitis pigmentosa.
This candidate drug, meaning a potential drug that needs a full evaluation, is being developed to target Usher syndrome and Retinitis Pigmentosa associated with faults in the USH2A gene, which is the commonest cause of deafness and blindness & also isolated Retinitis Pigmentosa. Orphan Drug status is a designation granted to drugs that can treat diseases that affect less than 200,000 people in the US. The status is given to QRX-411 makes it eligible for seven years in the US and ten years in the EU of marketing following its approval. The orphan drug designation also makes a company benefit regarding tax credits on an exemption from the FDA user fees plus assistance from the FDA in the clinical trial design.
I have read that QRX-411 targets severe degenerative retinal disease for which there are no other treatments available to restore vision or indeed impede the progression of the disease. The QRX-411 targets mutations in the USH2A gene and pre-clinical studies have shown some positive results.
The company is also trialling drugs for other genetic retinal conditions for which currently there no therapies available. It is looking at a drug called QR-110 for Leber congenital amaurosis type 10 (CEP290 associated LCA), which has also been given orphan drug designation in the US and Europe. It is developing QRX-1011 for Stargardt’s disease and QRX-504 for Fuchs’ endothelial corneal dystrophy.
There are so many potential genetic therapies that five years from now we will be writing very different blogs and many more patients will be receiving treatments that either improve the vision or slow down deterioration through these developing therapies for ophthalmology using a novel RNA oligonucleotides drug discovery platform. Currently, the candidate drugs are being the equivalent of interviewing to find out whether they will be any use in the job.
If you would like to know more about potential treatments on the horizon for inherited retinal disease, you may discuss these at consultation with Professor Michel Michaelides, who is a world leading expert on inherited retinal diseases and is involved in many trials internationally and nationally. Professor Michel Michaelides looks after many patients at Clinica London who have or are worried that they may have inherited retinal disease (IRD).