Gene therapy restores hearing

Regeneron Pharmaceuticals has released preliminary data from the first two patients treated with the investigational gene therapy DB-OTO. At the American Society for Gene and Cell Therapy (ASGCT) annual meeting in May, the company disclosed that, during the CHORD clinical trialdesigned to evaluate safety and tolerability, the gene therapy improved hearing in two children with profound genetic deafness due to a mutation in the otoferlin gene. In one child, first dosed at age 11 months, DB-OTO improved hearing to normal levels within 24 weeks. The second child, age 4, saw initial hearing improvements after 6 weeks. The trial is still recruiting children from the United Kingdom, Spain and the United States with otoferlin-related deafness.

The new drug, DB-OTO, is designed to treat children whose hearing loss is caused by mutations in the OTOF gene, which encodes the otoferlin involved in synaptic vesicle fusion in the inner ear. Lack of a functional OTOF gene can cause congenital deafness by interfering with sound transmission from sensory cells in the inner ear to the auditory nerve. The gene therapy delivers a working copy of the otoferlin gene using a neutralized adeno-associated virus that is injected into the inner ear under general anesthesia, in a procedure similar to the one used for cochlear implantation.

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