For the first time in the Netherlands, Radboudumc has treated a patient with a specific form of the hereditary eye disease retinitis pigmentosa (RP) with a new form of experimental gene therapy. During the treatment, a properly functioning gene is injected under the retina so that it can replace the function of a malfunctioning gene. The aim is to prevent blindness with this therapy. The treatment is part of an international clinical study, in which Amsterdam UMC is also involved as a Dutch treatment center for gene therapy. Doctors in Amsterdam UMC will also perform this operation soon.
A new form of experimental gene therapy has been developed specifically for the RPRG gene. The experimental treatment consists of an operation under anesthesia. The drug, which consists of a non-pathogenic virus with a properly functioning RPGR gene, is injected under the retina. This well-functioning gene must replace the diseased gene on the spot. The patient can go home after the procedure and return the next day for a check-up. In the period after the procedure, the patient remains under the supervision of the clinical research team to monitor the progress.
Patient after first check: “If the recovery continues like this, I will immediately sign for my second eye!”
Increase independence and independence
It is expected that through this therapy, the disease will remain stable or possibly improve. With this new gene therapy, the doctors and researchers hope to eventually be able to treat the cause of this form of RP, thereby guaranteeing the independence and independence of patients with good vision. This study may also open doors to treatments for other inherited retinal disorders.
Hereditary eye disorder – retinitis pigmentosa (XLRP-RPGR)
This specific form of retinitis pigmentosa (XLRP-RPGR) leads to blindness. It mainly occurs in men, because the cause lies on the X chromosome. Men have one X chromosome and women have two. Women therefore have one normal RGPR gene ‘left’ with a hereditary change in one RGPR gene. In principle, one normally functioning RPGR gene is sufficient to prevent the disease from developing. Women can also get the disease, but it is less common. Affected individuals can see well as children, but slowly become visually impaired and blind later. One in 3000 Dutch people suffers from a form of retinitis pigmentosa. In ten to twenty percent of cases, the disease is caused by a change in the RPGR gene, the gene for which this experimental gene therapy is intended.
Gene therapy as a treatment
Gene therapy for patients with another congenital form of retinitis pigmentosa due to genetic defects in another gene, the RPE65 gene, has already been proven to be effective. In the Netherlands, the three centers of expertise, Radboudumc, Amsterdam UMC and Rotterdam Eye Hospital, carry out this treatment.