A new gene therapy to treat inherited deafness produces a lasting cure, a new international study has found.

The treatment, which targets the OTOF gene, restored hearing in 90% of participants, researchers reported April 22 in the journal Nature.

These results have lasted up to at least two and a half years after treatment, researchers said.

“It’s remarkable to see patients go from complete deafness to being able to hear,” said senior researcher Zheng-Yi Chen, an associate scientist and chair of otolaryngology at Mass Eye and Ear in Boston.

“For many patients, that also means the ability to develop and use speech,” Chen said in a news release.

Gene mutations account for up to 60% of hearing loss present at birth, researchers said in a news release.

This new study focused on a gene therapy designed to treat deafness caused by mutations in the OTOF gene.

This gene provides the body with instructions to make a protein called otoferlin, which is essential for hearing. Without otoferlin, hair cells in the inner ear can’t pass sound signals to the brain, resulting in severe or complete deafness at birth.

The treatment involves a single injection into the inner ear that uses a hollowed-out virus to deliver a working copy of the OTOF gene, researchers said.

In this trial, researchers recruited 42 patients across eight sites in China, ranging in age from infants not quite 1 year old to adults in their 30s.

Each person received one of three doses of a single gene therapy treatment: 36 in one ear and six in both ears. Researchers then followed participants for up to 2.5 years to see if the treatment was safe and effective.

About 90% had hearing improvement in their treated ears, often within weeks of treatment and improvement continued over time, researchers said.

As hearing returned, participants became better at understanding speech and language. Young children and those with healthier inner ears saw the greatest improvement, and those treated in both ears did better than those treated in just one ear.

Of the three adults treated, two experienced some hearing recovery, although less than that of younger patients, researchers said.

“It is very encouraging to see meaningful improvements in some adult patients,” Chen said. “It suggests there may be more flexibility in the human auditory system than we expected.”

Researchers plan to continue long-term follow-up and hope to start a future clinical trial in the U.S. They also are exploring gene therapies for other forms of inherited hearing loss.

“These results show that restoring hearing is possible even after years of deafness,” lead researcher Dr. Yilai Shu, a professor at Eye & ENT Hospital of Fudan University in China, said in a news release. “We are now working to expand this approach to other genetic causes of hearing loss.”

More information

The American Society of Gene + Cell Therapy has more on genetic hearing loss.

SOURCE: Mass General Brigham, news release, April 22, 2026