Gene Therapy Revives Hearing in Five Children with Deafness

A breakthrough in the field of genetic deafness treatment has been reported from China, where an innovative gene therapy has successfully restored hearing in five out of six children who were born with total deafness. The study, published in The Lancet, details a trial conducted by researchers from the Eye & ENT Hospital at Fudan University in Shanghai, in collaboration with experts from Mass Eye and Ear in Boston.

The trial utilized an adeno-associated virus (AAV) to introduce a functional version of the otoferlin gene into the inner ears of the children. Otoferlin is a gene known to play a critical role in the auditory process. The patients involved in the study were all confirmed to have mutations in this gene, which was the root cause of their deafness.

The outcomes of the trial were impressive; within a 26-week period, five of the children showed significant hearing recovery. This was evidenced by a substantial reduction in their auditory brainstem response, a measure that assesses the inner ear's communication with the brain in response to sound. The improvement ranged from 40 to 57 dB, indicating a notable enhancement in their ability to process auditory information.

Post-treatment, the children exhibited remarkable progress in their speech perception and were able to engage in normal conversations. The safety profile of the gene therapy was also favorable, with no dose-limiting toxicities observed. The study recorded 48 adverse events, most of which were of low severity. There were two instances of more serious side effects, classified as grade 3, but these were temporary and had no lasting effects on the children.

Zheng-Yi Chen, an associate scientist at Mass Eye and Ear and one of the study's authors, expressed his astonishment at the trial's results, describing them as "truly remarkable." He highlighted the progressive improvement in the children's hearing and speech over the weeks, noting that this advancement is comparable to the introduction of cochlear implants six decades ago, marking a significant milestone in combating hearing loss.

The Lancet's publication of this study follows closely on the heels of Eli Lilly's announcement regarding its otoferlin-based gene therapy, AK-OTOF, which restored the hearing of an 11-year-old within 30 days. The child, who had profound hearing loss from birth, achieved normal hearing levels at certain frequencies by day 30. Similarly, Regeneron reported positive results with its gene therapy candidate, DB-OTO, which improved the auditory brainstem response in an infant under two years of age within six weeks of treatment.

These developments signal a promising future for gene therapy in treating congenital hearing loss, offering hope to those affected and their families. The scientific community eagerly anticipates further advancements in this field, which could potentially transform the lives of individuals with hearing impairments.