It’s been a good year for gene therapy, after decades of false starts. On Tuesday, the Food and Drug Administration (FDA) approved the first gene therapy to treat an inherited genetic disease. Earlier this year, the agency approved the first gene therapy in the U.S., for the treatment of leukemia in children, and several months later approved a related gene therapy for treating lymphoma.
The new approval will treat a type of retinal dystrophy, a rare vision disorder that involves mutations to genes critical to retinal function; retinal cells convert light into electrical signals to the brain, which translates them into images. People with mutated retinal genes can eventually lose their sight and become blind.
The new gene therapy, called voretigene neparvovec-rzyl, or Luxturna, and developed by Spark Therapeutics, delivers normal copies of the aberrant gene into retinal cells. These then produce the normal protein the cells need to translate the electrical signals to the optic nerve. The normal genes are delivered by a modified adenovirus, similar to the ones responsible for the common respiratory infections.
The FDA approved the gene therapy based on a study of 31 people with the mutated gene. After a year, people who received the normal gene were better able to complete an obstacle course under low-light conditions compared to people who didn’t receive the therapy. NPR reported that people who were treated were able to read, ride bicycles and see faces, which they weren’t able to do before.
“I believe gene therapy will become a mainstay in treating, and maybe curing, many of our most devastating and intractable diseases,” Dr. Scott Gottlieb, commissioner of the FDA, said in a statement announcing the approval. “This milestone reinforces the potential of this breakthrough approach in treating a wide-range of challenging diseases.”
Gene therapy hasn’t always had such a rosy future; in 1999, a teen who volunteered for a promising gene therapy trial to treat his genetic liver disease died while in the trial. The university running the trial closed its gene therapy program, and the technique fell out of favor.
But better understanding of genetics, as well as improved techniques for delivering and controlling genes, is contributing to a resurgence in interest in gene therapy-based techniques. Still, concerns about long-term effects of gene therapies, and the high cost of the technology, mean that these innovations won’t be widely available any time soon. Delivering the healthy genes requires genetic engineering to produce the gene, load it into the adenovirus vehicle and safely load them into the retinal site. Spark Therapeutics has not announced how much the therapy will cost.