Otarmeni is the first drug that can treat genetic hearing loss in children by addressing its underlying cause. The US Food and Drug Administration approved the Regeneron gene therapy on April 23, 2026, under an expedited pathway. In the pivotal clinical trial, 42 percent of patients achieved normal hearing, including the ability to understand whispered speech.
A Rare but Devastating Diagnosis
The drug targets a specific form of inherited deafness. It is designed for children who inherit a defective copy of the OTOF gene from both parents. This gene encodes otoferlin, a protein in the inner ear's hair cells that converts sound signals into electrical impulses the brain can process. Without otoferlin, affected individuals perceive some sound energy but the signal never fully reaches the brain, resulting in severe to profound hearing loss from birth.
Until now, the cochlear implant was the only durable treatment option, an electronic device surgically implanted in the inner ear. Otarmeni offers a biological alternative for the first time: the therapy delivers a functional copy of the OTOF gene directly into the cochlea's hair cells.
How the Therapy Works
Otarmeni is administered as a one-time infusion per ear, in a procedure similar to cochlear implantation. Because the OTOF gene is too large for a single viral carrier, the developers use two different AAV1 vectors (adeno-associated viruses) that together transport the complete genetic material. This dual-vector strategy is one of the technically noteworthy aspects of the approach.
The FDA approval came under the new National Priority Voucher Program for rare conditions with urgent medical need. From submission of the application to approval took 61 days. This is an accelerated approval based on a surrogate endpoint, the hearing threshold. Regeneron must demonstrate in follow-up studies that improved hearing thresholds also translate to measurable improvements in speech development.
Prerequisites for treatment: the inner hair cells must still be intact, and the patient must not already have a cochlear implant in the ear being treated.
Trial Results
The pivotal trial enrolled 24 children aged 10 months to 16 years, all with biallelic OTOF gene mutations and severe to profound hearing loss. Of the 20 participants in whom the primary endpoint was evaluated, 80 percent met the goal: a hearing threshold of 70 decibels or better at 24 weeks. That corresponds to crossing from severe deafness into the range of limited but functional hearing.
At a longer follow-up of 48 weeks, 42 percent of patients showed normal hearing, defined as a threshold of 25 decibels or better. This group was able to understand whispered speech. One participant did not respond to the therapy; the researchers believe a delivery problem during surgery was the cause, not a fundamental failure of the treatment.
Access and Cost
Regeneron has announced it will provide Otarmeni free of charge to all clinically eligible patients in the United States. That covers the drug itself. Costs for surgery, anesthesia, hospitalization, and follow-up care are not included and can be substantial. The number of children in the US with biallelic OTOF mutations is not precisely known; estimates suggest a few thousand.
Outlook
Otarmeni is the first gene therapy worldwide approved for any form of genetic hearing loss. For children diagnosed with OTOF mutations, it may offer an alternative to a lifelong cochlear implant, with the key difference that it requires no device and restores biological hearing.
The FDA approval also opens the door for similar approaches targeting other forms of genetic deafness. The OTOF gene is just one of more than 150 genes implicated in hearing loss. Several biotech companies are developing gene therapies for other mutations, with initial clinical results from additional gene loci expected around 2027.