New Gene Therapy Restores Hearing for People Born Deaf

A gene therapy targeting a specific genetic mutation has restored hearing in ten patients born with congenital deafness, according to research published in the journal Nature Medicine. The study, involving researchers from the Karolinska Institutet and partners at universities and hospitals in China, utilized a single injection to deliver a functional gene directly into the inner ear.

The trial included ten patients between the ages of 1 and 24 who were treated across five hospitals in China. Every participant experienced improved hearing, with some patients showing rapid gains within one month of the procedure. Researchers reported that the therapy was well-tolerated by all participants.

Targeting the OTOF Gene

The treatment specifically targets mutations in the OTOF gene. These mutations prevent the body from producing sufficient amounts of otoferlin, a protein essential for transmitting sound signals from the inner ear to the brain.

Deafness linked to OTOF mutations is categorized as a type of auditory neuropathy. What we have is a spectrum of disorders where the inner ear is capable of detecting sound, but the system struggles to send that information to the brain for processing.

To correct this deficiency, researchers used a synthetic adeno-associated virus (AAV) as a vector to deliver a working version of the OTOF gene into the inner ear. This approach aims to restore the production of the otoferlin protein and enable the transmission of auditory signals.

This is a huge step forward in the genetic treatment of deafness, one that can be life-changing for children and adults

Maoli Duan, consultant and docent at the Department of Clinical Science, Intervention and Technology, Karolinska Institutet

Medical Context and Prevalence

While Notice at least 150 genes linked to hearing loss, the OTOF gene is noted for having an unusually high safety profile for genetic intervention. In the United States, OTOF mutations are estimated to cause hearing loss in approximately 20 to 50 babies born each year.

For decades, cochlear implants have been the primary method for providing hearing to infants born deaf. However, gene therapy offers the potential to restore natural hearing by addressing the underlying genetic cause of the condition.

Regulatory and Future Developments

The development of OTOF-targeted therapies has seen international collaboration, with research groups in France, China, and the United States working on similar drugs. In the United States, the company Regeneron planned to file for FDA approval of its specific treatment by the end of 2025.

If approved, the United States would become the first country to authorize a gene therapy for hearing loss. Researchers suggest that the success of treating OTOF mutations could eventually lead to similar therapeutic approaches for more common types of genetic hearing loss.