Chinese Gene Therapy Restores Hearing in Five of Six Treated Children

Hearing, child_iStock, AaronAmat

Pictured: A girl cupping her ear/iStock, AaronAmat

An experimental gene therapy being developed in China was able to restore the hearing in five of six treated children with genetic deafness, according to the results of a small study published Wednesday in The Lancet.

The single-arm, single-center trial—co-led by investigators from Eye & ENT Hospital at Fudan University in Shanghai and from Mass Eye and Ear in Boston—used an adeno-associated virus (AAV) to deliver a functioning copy of the human otoferlin gene into the inner ears of six children who had been suffering since birth from “total deafness,” according to Mass Eye and Ear’s statement. All patients were confirmed to be harboring mutations on the otoferlin gene.

Results showed that through 26 weeks of follow-up, five children recovered their hearing—as demonstrated by a 40 to 57 dB reduction in their auditory brainstem response, which measures how well the inner ear communicates with the brain in response to sound stimuli.

Following treatment with the investigational gene therapy, the children also showed “dramatic improvements in speech perception” and could hold normal conversations, according to the announcement.

In terms of safety, the small study documented no dose-limiting toxicities. Forty-eight adverse events were recorded in total, most of which were low-grade. There were two cases of grade 3 side effects but these were transient and were deemed to have no long-term impact on the children.

Zheng-Yi Chen, one of the authors on the study and an associate scientist at Mass Eye and Ear, in a statement called the results of this early trial “truly remarkable.”

“We saw the hearing ability of children improve dramatically week by week, as well as the regaining of their speech,” Chen said. “Not since cochlear implants were invented 60 years ago, has there been an effective treatment for deafness. This is a huge milestone that symbolizes a new era in the fight against all types of hearing loss.”

Wednesday’s Lancet article comes one day after Eli Lilly reported that its own otoferlin-based gene therapy AK-OTOF restored an 11-year-old’s hearing within 30 days of administration. As in the case of the Chinese trial, the young patient had suffered from “profound hearing loss” since birth but was able to reach normal hearing range at some frequencies by day 30.

Also developing a gene therapy for congenital hearing loss is Regeneron, which in October 2023 reported that its candidate DB-OTO improved auditory brainstem response in an infant younger than two years of age within six weeks of treatment.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. He can be reached at or

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