Researchers at Sweden’s Karolinska Institutet, in collaboration with medical institutions in China, have successfully restored hearing in ten patients using a single gene therapy injection. The study, published in the journal Nature Medicine, suggests that the treatment is both safe and highly effective at addressing congenital hearing loss caused by mutations in the OTOF gene.
Patients ranging from toddlers to adults participated in the trial, which involved injecting a functional copy of the OTOF gene directly into the inner ear. This gene is responsible for producing otoferlin, a protein critical for transmitting sound signals from the ear to the brain. Participants who lacked this protein were previously unable to process sound.
Rapid results for patients
Results appeared quickly, with most participants showing measurable hearing improvement within just one month. After six months of monitoring, the average hearing sensitivity among the group improved from 106 decibels to 52 decibels.
"This is a huge step forward in the genetic treatment of deafness, one that can be life-changing for children and adults," said Maoli Duan, a docent at the Karolinska Institutet and one of the study’s authors. While younger children showed the most dramatic results—including one seven-year-old who began holding conversations with her mother shortly after the procedure—the therapy also yielded significant improvements in older participants.
Medical teams monitored the subjects for up to 12 months, reporting no serious adverse reactions. The only commonly cited side effect was a temporary reduction in neutrophils, a specific type of white blood cell.
Dr. Duan noted that the success of this trial opens the door for treating other forms of genetic deafness. Researchers are already looking toward targeting more complex genes, such as GJB2 and TMC1, which are linked to more common types of hearing loss.
"OTOF is just the beginning," Duan said. "We are confident that patients with different kinds of genetic deafness will one day be able to receive treatment." The trial was funded by several Chinese research programs and Otovia Therapeutics Inc., the company responsible for developing the gene therapy.
