EMA Fast-Tracks Regeneron Gene Therapy for Rare Hearing Loss

Regeneron Pharmaceuticals said the European Medicines Agency (EMA) has accepted for review under its Accelerated Assessment pathway the Marketing Authorization Application (MAA) for Otarmeni (lunsotogene parvec), an investigational gene therapy designed to treat biallelic OTOF variant-associated hearing loss, a rare inherited form of deafness.

If approved, Otarmeni would become the first gene therapy authorized in the European Union for OTOF-related hearing loss, representing a potentially transformative treatment for a condition historically viewed as permanent and managed primarily through lifelong assistive devices.

Otarmeni, previously known as DB-OTO, has already received orphan designation from the EMA, a regulatory status intended to encourage development of therapies for rare diseases affecting small patient populations.

The Accelerated Assessment procedure is designed to shorten review timelines for medicines considered of major public health interest or those representing significant therapeutic innovation. Acceptance into the pathway signals regulators believe the therapy may address a substantial unmet medical need.

The European filing is supported by data from the pivotal CHORD clinical trial, which evaluated the safety and efficacy of a single dose of Otarmeni in 24 pediatric patients aged between 10 months and 16 years with OTOF-related hearing loss.

Participants in the study received treatment through intracochlear infusion, a surgical procedure that delivers therapy directly into the inner ear. Ten participants received unilateral treatment in one ear, while 14 underwent bilateral administration in both ears.

Earlier results from the CHORD study involving 20 patients also formed the basis of a recent regulatory decision in the United States. In April 2026, the therapy received accelerated approval from the U.S. Food and Drug Administration, making Otarmeni the first approved gene therapy for OTOF-related hearing loss in the country.

Regeneron said regulatory submissions are also planned in additional global markets, including Japan.

OTOF-related hearing loss is an ultra-rare inherited disorder estimated to affect approximately 46 newborns annually across the European Union. The condition results from mutations in the OTOF gene, which disrupt production of otoferlin, a protein essential for communication between sensory cells in the inner ear and the auditory nerve.

Although patients with OTOF-related hearing loss typically have intact ear structures, the lack of functional otoferlin prevents effective sound signal transmission to the brain, leading to profound hearing impairment from birth.

Historically, management of the condition has relied on hearing devices and cochlear implants designed to amplify sound or improve auditory perception. However, such interventions do not restore natural auditory signaling or recreate the full spectrum of sound processing.

Gene therapies such as Otarmeni seek to address the root biological cause of disease by delivering functional genetic material directly into affected tissues. In this case, the therapy uses an adeno-associated virus (AAV) vector to introduce a working version of the OTOF gene into the inner ear, potentially restoring auditory communication pathways.

Regeneron emphasized that while Otarmeni has secured approval in the United States, outside the U.S. its safety and efficacy remain under regulatory evaluation. A final decision from European authorities will depend on the outcome of the accelerated review process and assessment of long-term clinical benefit and safety.

The regulatory milestone underscores growing momentum in gene therapy development, particularly for rare pediatric disorders where treatment options have historically been limited or nonexistent.