The Radboudumc has treated, for the first time in the Netherlands, patients with the hereditary X-linked retinal disorder Retinitis Pigmentosa with a new form of investigational gene therapy. The treatment is part of an international clinical study involving not only Radboudumc but also Amsterdam UMC. There, too, this procedure will be performed soon.
This specific Retinitis Pigmentosa disease type (XLRP-RPGR) leads to blindness. It occurs mainly in young men because the cause is in a gene on the X chromosome, of which men have one (and women two). Women can also get the disease, but it is less common. Affected individuals can see well during childhood, but slowly become partially sighted and later blind. One in 3,000 Dutch suffer from a form of Retinitis Pigmentosa. In ten to twenty percent of cases, the disease is caused by a change (mutation) in the RPGR gene, which is the target of the investigational gene therapy in this study.
Treatment with healthy copy of gene
An investigational gene therapy has been developed specifically for this gene. The investigational treatment involves surgery under anesthesia in which the drug, which consists of a non-pathogenic virus with a healthy copy of the RPGR gene, is injected under the retina to replace the disease causing gene. The patient is released from the hospital after the procedure and returns to the outpatient clinic the following day. In the period after surgery, the patient remains under close observation of the clinical research team.
First patient after first check-up: “If this is it and my recovery continues to go well, I’ll sign up for my other eye now?”
Increasing independence and autonomy
It is anticipated that after treatment with this investigational therapy, vision would remain stable or potentially improve. The doctors and researchers hope the investigational gene therapy will be able to treat the underlying cause of XLRP, and enable the independence of patients living with XLRP. This study may also have the effect of opening doors to treatments for other hereditary retinal diseases.
Gene therapy as a treatment
Gene therapy for patients with a congenital form of Retinitis Pigmentosa due to genetic defects in another gene, the RPE65 gene, has already been proven effective. In the Netherlands, three centers of expertise, namely the Radboudumc, Amsterdam UMC, and the Rotterdam Eye Hospital perform this treatment.