The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has voted to recommend marketing authorization for voretigene neparvovec (Luxturna, Spark Therapeutics) for the indication of inherited retinal dystrophy caused by RPE65 gene mutations in adults and children.

Voretigene neparvovec is a gene transfer vector that replaces the mutated gene in retinal cells. It will be available in concentrated form (5 x 1012 vector genomes/mL) and as a solvent for the injectable solution.

It is a one-time therapy for each eye that is injected beneath the retina, according to information on the company's website. The second eye is treated at least 6 days after the first eye.

Among the drug's benefits is its ability to enhance night vision. Its most frequently reported adverse effects are conjunctival hyperemia, cataract, and increased intraocular pressure.

Voretigene neparvovec received orphan medicine designation during its development on April 2, 2012, as it is for the treatment of a rare genetic disorder that causes vision loss and typically leads to blindness. The US Food and Drug Administration approved voretigene neparvovec for this indication on December 19, 2017.

The committee's vote follows a positive assessment by the Committee For Advanced Therapies as the drug is "an advanced therapy medicinal product," the EMA notes in a news release.

The company conducted a clinical trial in 31 patients aged 4 to 44 years with genetic mutations in both copies of the RPE65 gene. Patients were required to have an adequate number of remaining retinal cells and a visual acuity of 20/60 or worse bilaterally and/or a visual field of fewer than 20 degrees.

Patients were required to be capable of performing the multi-luminance mobility test within the light level range tested but be incapable of passing at the darkest light level.

Drug's effect

Researchers treated two groups of patients at different times to allow for comparison of results between treated and untreated patients. The second group underwent treatment 1 year after the first group.

Patients received treatment in the second eye 6 to 18 days after treatment of the first eye and adhered to a prescribed course of medication to limit immune response-related risks. They underwent evaluation 1 year after treatment to measure the drug's effect.

After 1 year, 55% of patients were able to perform the test at two light levels darker than before treatment using both eyes. Sixty-five percent of patients in the first group and 89% in the second group could navigate through the test course at the darkest light level, which correlated with a moonless summer night.

The drug's full indication is for the "treatment of adult and pediatric patients with vision loss due to inherited retinal dystrophy caused by confirmed bi-allelic RPE65 mutations and who have sufficient viable retinal cells," according to the news release. A retinal surgeon with macular surgery experience should administer the drug.

The summary of product characteristics will include detailed recommendations for product use and be published in the European public assessment report, which will be made available in all official European Union languages after the European Commission grants the marketing authorization.