Luxturna (voretigene neparvovec) Gene Therapy
The RPE65 gene provides instructions for making a protein that is essential for normal vision function. The RPE65 protein is involved in a multi-step process called the visual cycle, which converts light entering the eye into electrical signals that are transmitted to the brain.
Mutations in the RPE65 gene lead to reduced or absent levels of RPE65 activity, blocking the visual cycle and resulting in impaired vision. People with biallelic RPE65 mutation-associated retinal dystrophy experience progressive deterioration of vision over time. Mutations in the RPE65 gene account for approximately 2% of cases of recessive RP and between 6 to 16% cases of Leber congenital amaurosis (LCA).
Luxturna works by delivering a normal copy of the RPE65 gene directly to retinal cells. These retinal cells then produce the normal RPE65 protein that converts light to an electrical signal in the retina to restore patient’s vision loss.
Luxturna is administered via subretinal injection in both eyes separately and on separate days. This procedure performed is a specialist eye surgeon. It is given as a one-time treatment.
The approval of Luxturna in the United States was based on the results of a clinical trial programme that enrolled a total 41 people between the ages of 4 and 44 years, all of whom had had confirmed biallelic RPE65 mutations. The effectiveness (efficacy) of the Luxturna was demonstrated by a Phase 3 clinical trial that enrolled 31 participants. The study found that at 1 year after the treatment, participants who received Luxturna had significantly improved light sensitivity, visual fields, and navigational ability under dim lighting conditions, compared with the control group (participants who were not treated Luxturna). In addition, no serious Luxturna-related adverse events were observed among individuals treated with Luxturna during the study.
In the United States, the manufacturers (Spark Therapeutics) have priced Luxturna at approximately $425,000 per one-off treatment (~$850,000 if a patient has the procedure on both eyes). They have also agreed an outcomes-based rebate arrangement with some healthcare insurers whereby the company will pay rebates if patient outcomes fail to meet a specified threshold, linking the payment for Luxturna to both short-term efficacy (30-90 days) and longer-term durability (30 months).
An article published in EyeNet Magazine® by the American Academy of Opthalmology® describes the impact that novel gene therapy Luxturna has had in the retina science research community, proving first-hand what can be achieved when we cooperate and unite to develop new therapeutics. Read the article here to hear another perspective on the importance of the Luxturna in bridging the gap to finding treatments for Inherited Retinal Diseases.
