A treatment developed in Spain and refined with US partners has helped children with genetic deafness hear for the first time
A gene therapy that restores hearing in children with a rare form of congenital deafness has delivered striking early results in an international clinical trial.
The treatment, known as DB-OTO, targets a mutation in the OTOF gene and could become the first approved gene therapy for inherited hearing loss if longer-term data confirm its safety and durability.
Genetic deafness affects thousands of children worldwide. Current treatment options rely on hearing aids or cochlear implants, which help many but do not correct the underlying defect. A treatment that restores natural hearing by fixing the root cause would change the clinical landscape for families living with profound deafness.
The trial and its impact
DB-OTO was developed by an American firm, Regeneron Pharmaceuticals, from decades of research by teams at Hospital Niño Jesús in Madrid and the University of Navarra.
In a trial of 12 children aged 10 months to 16 years, 11 showed marked improvement within weeks of treatment.
Three now hear at normal levels and can detect whispers and quiet speech. Before the therapy, they could only sense sounds louder than 90 decibels - that’s a motorcycle engine kind of level.
Parents described emotional first reactions as their children turned toward voices or smiled at new sounds. Several began to develop speech soon after treatment.
How the therapy works
The OTOF mutation stops the inner ear’s hair cells from sending sound signals to the brain. DB-OTO delivers a working copy of the gene directly into the cochlea through a single surgical procedure.
Early results suggest this restores the cells’ ability to process sound and may remove the need for hearing aids in some cases.
Clinical evidence to date
Data presented at the American Academy of Otolaryngology-Head and Neck Surgery meeting and published in the New England Journal of Medicine show sustained improvements in hearing and speech perception.
Some children can now recognise words without lipreading and respond to speech in noisy settings. Follow-up testing indicates stable or improving responses over time.
Regeneron’s Phase 1/2 CHORD trial is continuing in the US, UK, and Spain and is assessing both single and bilateral injections. Baseline testing showed profound hearing loss with no detectable responses above 100 decibels, making the gains especially significant.
Looking ahead
Researchers emphasise the need for long-term monitoring to confirm how durable the improvements will be and ensure the therapy’s safety.
Although the OTOF mutation is rare, the same approach could be adapted for more common forms of genetic deafness, such as those linked to GJB2.
“This work is exciting because it targets the root cause of deafness rather than compensating for it,” said Abigail Pillay, a Clinical Audiologist at Hearology®. “Families should know that while the results are promising, longer-term evidence is required before this becomes routine care.”
If future trial data continues to hold up, DB-OTO could become the first gene therapy to correct congenital deafness. For the children treated so far, the ability to hear natural sound for the first time has already been life-changing.
References
- Medical breakthrough as children with incurable deafness hear for first time – thanks to decades of genetic research carried out in Spain - News story on the breakthrough
- DB-OTO Results in the New England Journal of Medicine Showcase Dramatic and Sustained Improvements in Hearing and Speech Perception in Children with Profound Genetic Hearing Loss - Regeneron Pharmaceuticals announcement on the gene therapy treatment
- The Future of Gene Therapy for Hearing Loss – The National Institute on Deafness and Other Communication Disorders (nidcd) overview of gene therapy’s potential for treating deafness.
