“Life-Changing” Gene Therapy Restores Hearing In Deaf Patients Within Weeks After Just One Shot

The therapy, which uses a synthetic virus to deliver a functional copy of a faulty gene to the inner ear, has been trialed in children before, but never in teenagers and adults.

“This is a huge step forward in the genetic treatment of deafness, one that can be life-changing for children and adults,” Maoli Duan, one of the study’s corresponding authors, said in a statement.

The researchers recruited 10 patients, with an age range from one to 24, all of whom had a rare type of congenital deafness or severe hearing impairment caused by mutations in a single gene: OTOF. This gene plays an important role in sending auditory signals from the ear to the brain, and without it, a person is rendered unable to hear.

However, by delivering a healthy version of the OTOF gene via a single shot through a membrane at the base of the cochlea, the team was able to ameliorate this impairment. They used a synthetic adeno-associated virus (AAV) to do so, administered across five hospitals in China, and the effect was swift.

Within a month, most patients had recovered some hearing, and within six, all demonstrated significant improvement. On average, the volume of perceptible sound improved from 106 decibels to 52 – that’s about the noise of a motorcycle to the sound of rainfall. 

For the younger patients, aged between 5 and 8, the response was especially noteworthy, but it still proved effective for the two oldest participants, who were aged 14 and 24, respectively.  

“This is the first time that the method has been tested in teenagers and adults, too,” Duan explained. “Hearing was greatly improved in many of the participants, which can have a profound effect on their life quality. We will now be following these patients to see how lasting the effect is.”

Importantly, the therapy was well tolerated, with no serious side effects in the year-long follow-up period.

Though more research is needed, with larger sample sizes, the findings offer hope to the 200,000 people or so around the world who are deaf due to an OTOF mutation. The scientists are also optimistic that the treatment could be expanded to other causes of deafness: “We and other researchers are expanding our work to other, more common genes that cause deafness, such as GJB2 and TMC1. These are more complicated to treat, but animal studies have so far returned promising results. We are confident that patients with different kinds of genetic deafness will one day be able to receive treatment,” said Duan. 

“OTOF is just the beginning.”

The study is published in Nature Medicine.