A groundbreaking gene therapy has enabled several deaf children to hear for the first time, marking a significant advancement in treating hereditary deafness. This breakthrough is seen as a potential “game changer” in developing new treatments for congenital hearing loss, which hasn’t seen a major innovation in decades.
The procedure, currently in trials around the world, targets a rare genetic mutation linked to congenital deafness, affecting a small fraction of the 26 million people globally born with the condition.
The Children’s Hospital of Philadelphia recently announced the successful treatment of 11-year-old Aissam Dam, born deaf, who is now able to hear. While Aissam still experiences mild-to-moderate hearing loss and may not acquire speech due to the brain’s limited window for learning language, this development is a significant step forward.
A separate trial in China, reported in The Lancet journal, involved six younger children, five of whom gained the ability to hear. Notably, some children in this trial, which commenced in 2022, had previously relied on cochlear implants but no longer need them post-treatment. One child, a one-year-old, responded verbally for the first time post-treatment, to the joy and amazement of all present.
Zheng-Yi Chen of the Massachusetts Eye and Ear hospital, a co-author of the study, described the treatment as a monumental leap forward since the invention of cochlear implants 60 years ago, signaling a new era in combating all types of hearing loss.
The gene therapy targets individuals with a mutation in the OTOF gene, hindering the production of the protein otoferlin. This protein is essential for converting sound vibrations into electrical signals in the inner ear. The therapy involves injecting a benign virus into the inner ear to deliver a functioning version of the OTOF gene, thereby restoring hearing.
The French trial, announced this week, aims to treat babies aged 12-31 months to facilitate language acquisition. Nawal Ouzren, CEO of Sensorion, which is developing the treatment, and hearing loss expert Dr. Natalie Loundon both view this advancement as a significant technological breakthrough that could revolutionize therapeutic care.
Researchers plan to monitor the participants of the Chinese trial to determine the long-term effectiveness of the treatment, which could be ready for regulatory approval within three to five years.
However, this treatment addresses only a fraction of genetic hearing loss cases, which are caused by over 150 different genes. But with the success seen in human trials mirroring that of mice studies, researchers are optimistic about developing similar treatments for other genetic causes of deafness.
The Pasteur Institute in France and Sensorion are already researching therapies for other common forms of hereditary deafness.