Groundbreaking Chinese gene therapy restores hearing for inherited deafness

A new gene therapy has restored hearing in children and adults with hereditary deafness, according to results from a closely watched clinical trial in China. The treatment targets mutations in the OTOF gene, a common cause of profound congenital hearing loss.

Researchers administered a single dose of the therapy using a modified virus carrying a healthy copy of the gene delivered directly into the inner ear of ten participants ranging from 18 months to nearly 24 years old. Within a month, all 10 showed measurable hearing improvement. After six months, average hearing thresholds improved from about 106 decibels, the level of profound deafness, to 52 decibels, a range that supports conversation and everyday listening.

The youngest children in the trial saw the most dramatic gains. One 7-year-old, previously unable to understand speech, regained near-normal hearing and was speaking fluently with her mother just four months after treatment. No serious side effects were reported. The most common issue was a temporary drop in neutrophil counts which was resolved during follow-up.

“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 consultant at Karolinska Institutet in Sweden and one of the study’s lead authors. “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.”