FDA Gives Green Light To the First Gene Therapy For Deafness

The Food and Drug Administration approved the first gene therapy to restore hearing for people who were born deaf. The decision, while only immediately affecting people born with a very rare form of genetic deafness, is being hailed as a milestone in the quest to treat hearing loss. “It’s the first time in history there’s a new drug for hearing loss,” says Zheng-Yi Chen, an associate scientist at Mass Eye and Ear in Boston who was not involved in the development of the therapy approved by the FDA Thursday. But his research team reported very promising results with a similar approach Wednesday. “I think it’s an historical event, a landmark, a great development for the whole field,” he says of the approval. […] The FDA’s decision was based on the results from the treatment of 20 patients born with a defective version of a gene known as OTOF, which is necessary to transmit sound from the ears to the brain.

Doctors infused billions of adeno-associated viruses into the patients’ ears by making a small incision behind the ear to open a small hole in the skull. The viruses carried a healthy version of the OTOF gene that had been split in half to fit inside the virus. The gene provides instructions to make the otoferlin protein, which is necessary for hair cells in the inner ear to transmit sound to the brain. Most of the patients began to hear for the first time within weeks, with the quality of their hearing improving over the following months, according to [Regeneron Pharmaceuticals, which developed the gene therapy and plans to offer it for free in the U.S. It should be available within weeks.]. The amount of hearing patients gained varied, but 80% achieved at least some significant hearing restoration and 42% ended up with normal hearing, which included the ability to hear whispers, Regeneron says. The hearing ability has lasted at least two years so far.

The treatment can only help patients with the very rare form of deafness that Smith was born with, which only affects about 50 children each year in the U.S. But similar gene therapies are showing promise for other forms of genetic deafness. And researchers hope someday gene therapy may help with common types of hearing loss, like from aging and loud noise.