From birth, pediatric patients showing symptoms of hearing loss have undergone gene therapy and recovered their hearing. Hereditary hearing loss is considered a representative intractable disease; however, there is currently no hearing gene therapy approved by the U.S. Food and Drug Administration (FDA).
On the 24th (local time), Regeneron Pharmaceuticals in the United States announced the results of a small clinical trial of the hearing gene therapy "DB-OTO" at the Winter Meeting of the American Academy of Otolaryngology-Head and Neck Surgery held in Orlando, Florida. According to the clinical trial results, hearing improvement was confirmed in 10 out of 12 participants.
DB-OTO treats abnormalities in the OTOF gene. OTOF produces otoferlin, a protein that transmits auditory signals to the brain. If otoferlin is not adequately expressed, "auditory neuropathy" occurs, leading to hearing loss. DB-OTO contains the gene that expresses the otoferlin protein, which helps restore hearing by producing otoferlin in patient cells.
In this trial, 9 out of 12 infants with auditory neuropathy received the gene therapy in one cochlea, while 3 received treatment in both cochleae. The clinical trial results showed significant hearing improvement in 10 patients, with 3 being diagnosed at levels close to "almost normal" and "normal." It was found that as patients' hearing improved, their language skills also improved.
Among the participants, 5 experienced temporary nausea, dizziness, and vomiting; however, these symptoms disappeared within 6 days after treatment. Two of these participants experienced severe symptoms, but Regeneron evaluated that this was not related to the gene therapy. The FDA has already designated DB-OTO as an orphan drug and a regenerative medicine therapy, while the European Medicines Agency (EMA) has also designated it as an orphan drug.
Regeneron noted, "Based on this research, we plan to develop treatment methods for pediatric patients experiencing hearing loss for other reasons," adding, "We anticipate that gene therapy will also be effective for noise-induced hearing loss, regardless of age."
Other global pharmaceutical companies are also showing interest in developing hearing gene therapies. Eli Lilly of the United States confirmed significant therapeutic effects in early clinical trials of their hearing gene therapy candidate "AK-OTOF" last year. Japanese pharmaceutical company Astellas has also acquired Frequency Therapeutics' hearing treatment candidate "FX-322" and is conducting clinical trials.