FDA Paving The Way For Approval Of Gene Therapy

Genes are incredibly important sequences of chromosomal DNA that are required for the production of a functional product. A gene mutation is any alteration of the sequence of DNA that makes up a gene. These gene mutations can either be hereditary or acquired (somatic). Many different diseases can result from genetic mutations. In some of these genetic mutations, the causes are known. For instance, there is a group of rare blinding conditions, retinal dystrophies, that are caused by a mutation in any one of more than 220 genes.

Retinitis pigmentosa is a subgroup of the inherited retinal dystrophies and is characterized by the reduced ability to perceive light and progressive loss of the visual field. More specifically, if a patient has two mutated copies of the gene RPE65 this leads to the inability of the eye to respond to light which ultimately leads to the destruction of photoreceptors in the retina.

There was a Phase 3 Study that was conducted, testing 29 individuals, all who have two mutated copies of the gene RPE65. 20 of these individuals were treated with voretigene neparvovec (Luxterna) and 9 were controls. Voretigene neparvovec (Luxterna) is a gene therapy treatment option that has a normal copy of the gene RPE65 loaded into a virus. This virus is then directly injected into the eye where the gene is normally expressed. At the end of the study, it was concluded that the patients who received treatment showed improved ability while the control patients did not.

Gene therapy is not necessarily a new idea but is one that most definitely comes with a lot of discussion. There has been an instance of death in regards to gene therapy trials and all of the potential risks are not known. Even though investors backed away and scientists began to doubt, gene therapy has continued to grow, currently with the demand for vectors so high that suppliers are oversubscribed. With this new novel gene therapy Luxterna, it is looking as if the FDA will approve it, giving their final decision before January 12th. With this decision comes a lot of ethical considerations. It will be interesting to see the reaction once the FDA has made their final decision in regards to potentially the first approved gene therapy treatment in the United States.

References:

“FDA Advisers Back Gene Therapy for Rare Form of Blindness.” Nature News, Nature Publishing Group, www.nature.com/news/fda-advisers-back-gene-therapy-for-rare-form-of-blindness-1.22819.

Russell, S. et al. Lancet 390, 849–860 (2017).