Spotlight on Research: Using gene replacement therapy to treat Retinitis Pigmentosa.
The Kvanta lab are investigating whether replacing a faulty gene can treat Retinitis Pigmentosa, an inherited form of blindness.
What is the question you are trying to answer?
This study is investigating the efficacy of a new gene therapy for retinitis pigmentosa. This approach uses a viral vector to replace the faulty, disease causing-form of a gene (RLBP-1) with a healthy copy (called CPK850). The viral vector is surgically injected under the retina of the patient. The team are investigating whether this gene replacement approach could improve visual function.
Anders Kvanta
St. Erik Eye Hospital & Karolinska Institutet
Why are you investigating this question?
Inherited retinal diseases (IRDs) such as Retinitis Pigmentosa (RP) involve a loss of light-sensing cells, leading to reduced night and colour vision. These diseases are often caused by a mutation in a single gene. Currently, this form of RP has no cure. A gene therapy using a viral vector (Luxturna) has already been proven successful for treating another form of RP, and approved by the EMA. We are conducting this clinical trial, called a ‘first-in-human’ trial, to determine first whether this is safe for use in humans, and secondly whether it is effective in preserving visual function. This is called a Phase 1/2 trial.
What will the next steps be?
At time of writing (September 202), 12 patients with mutations in the RLBP-1 gene have been treated with a viral vector containing the normal copy of this gene as a part of the Phase 1/2 clinical trial (NCT03374657). The preliminary safety and efficacy data was recently published (insert link) and showed significant improvement in night vision for 11 patients, improving self-perceived quality of life. If the results from this trial show that the therapy is effective, we aim to move on to further clinical trials with a greater number of participants. This will allow us to refine the methods of providing the therapy. You can read more here.
What impact do you hope for this to have in your field?
Currently, this form of RP has no cure, meaning that patients living with it are guaranteed to lose their vision over time. Typically, individuals with this variant will be completely blind by early adulthood. This can impact the individual’s independence and ability to continue with daily activities. If these clinical trials are successful, we can offer a therapy which would preserve visual function, and so preserve the individual’s independence.