Pull to refresh
Logo
Daily Brief
Following Why Ranks Sign Up
Gene therapy restores hearing in deaf patients

Gene therapy restores hearing in deaf patients

New Capabilities

Genetic deafness moves from permanent disability to treatable condition

July 3rd, 2025: Gene Therapy Restores Hearing in Deaf Patients

Overview

Children born profoundly deaf can now hear their parents' voices. A single injection of gene therapy into the inner ear restored hearing in dozens of patients, moving genetic deafness from permanent disability to treatable condition. The effect is rapid—most patients recover hearing within weeks and retain it for at least two years.

Three major clinical trials across the U.S., China, and Europe have proven that replacing the faulty OTOF gene restores otoferlin—an important protein for transmitting sound signals in the inner ear. Unlike cochlear implants that provide artificial electrical stimulation, gene therapy restores natural acoustic hearing. The best results come in young children, but teenagers and adults have also regained hearing; Regeneron plans to seek FDA approval by end of 2025.

Play on this story Voices Debate Predict

Key Indicators

54 dB
Average hearing improvement
Patients went from complete deafness (106 dB) to moderate hearing loss (52 dB)
11 of 12
Patients with restored hearing
Regeneron's DB-OTO trial success rate, with 3 achieving normal hearing
2-8%
Deafness cases from OTOF
Approximately 200,000 people globally have OTOF-related hearing loss
30 days
Time to hearing recovery
Most patients showed measurable hearing improvements within one month

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

Sign up to generate historical perspectives on this story.

Log in Sign Up

Play

Exploring all sides of a story is often best achieved with Play.

Log in to play. Track your picks, climb the leaderboards. Log in Sign Up
Predict 4 ways this could play out. Contrarian picks score more — points lock when the scenario resolves. Log in to play
Timeline Five events from this story — drag them oldest to newest. Log in to play
Connections Sixteen names from the news. Find the four hidden groups of four. Log in to play

People Involved

Yilai Shu
Yilai Shu
Led first successful human gene therapy trial for hearing loss
 John V. Brigande
John V. Brigande
Pioneering fetal gene therapy for congenital deafness

Organizations Involved

Regeneron Pharmaceuticals
Regeneron Pharmaceuticals
Biopharmaceutical partner
Leading developer of DB-OTO gene therapy, seeking FDA approval

Developer of DB-OTO, the most advanced gene therapy for OTOF-related hearing loss.
Eli Lilly and Company
Eli Lilly and Company
Pharmaceutical company
Developing AK-OTOF gene therapy through acquired subsidiary

Acquired Akouos in 2022 for $487M to develop gene therapies for hearing loss.
Sensorion
Sensorion
Biotechnology Company
Advancing SENS-501 through dose-escalation trial

French biotech developing SENS-501 gene therapy for OTOF-related hearing loss.
Children's Hospital of Philadelphia
Children's Hospital of Philadelphia
Pediatric Academic Medical Center
First U.S. site to administer gene therapy for genetic hearing loss

Performed the first gene therapy procedure for genetic hearing loss in the United States.

Timeline

January 2001 July 2025

14 events Latest: July 3rd, 2025 · 11 months ago Showing 8 of 14
Tap a bar to jump to that date

  1. Gene Therapy Restores Hearing in Deaf Patients

    Latest Publication

    Nature Medicine publishes expanded results: 10 patients with OTOF mutations show rapid hearing recovery including teenagers and adults.

  2. Regeneron Presents 48-Week Follow-Up Data

    Results

    Patients show sustained hearing gains with significant speech development progress at Association for Research in Otolaryngology meeting.

  3. Sensorion Advances to Higher Dose

    Clinical Trial

    Data monitoring committee clears AUDIOGENE trial to proceed with threefold higher dose in second cohort.

  4. DB-OTO Results Published in NEJM

    Publication

    Regeneron's trial shows 11 of 12 patients improved, with 3 achieving normal hearing. No drug-related adverse events.

  5. Sensorion Reports Positive First-Cohort Data

    Results

    SENS-501 low-dose cohort patient shows measurable hearing improvements and 145% IT-MAIS score increase.

  6. Bilateral Treatment Shows Speech Gains

    Results

    Study demonstrates children treated in both ears develop better speech perception and music recognition.

  7. CHOP Patient Achieves Hearing Recovery

    Results

    First U.S. patient shows improvement from profound deafness to mild-moderate hearing loss within four months.

  8. China Reports 5 of 6 Children Gained Hearing

    Results

    Fudan University team publishes results showing bilateral gene therapy restored hearing and speech in five children.

  9. First U.S. Patient Treated at CHOP

    Treatment

    11-year-old receives AK-OTOF gene therapy at Children's Hospital of Philadelphia, first in United States.

  10. Major Clinical Trials Launch in U.S.

    Clinical Trial

    Regeneron's CHORD trial and Eli Lilly's AK-OTOF-101 trial begin enrolling patients.

  11. First Patient Receives OTOF Gene Therapy

    Clinical Trial

    Yilai Shu's team at Fudan University treats the first patient with RRG-003, launching first successful human trial.

  12. Eli Lilly Acquires Akouos for $487M

    Corporate

    Lilly buys gene therapy biotech Akouos to develop treatments for genetic hearing loss.

  13. First Gene Therapy Trials for Hearing Loss Begin

    Clinical Trial

    Novartis initiates CGF166 trial targeting ATOH1 gene, though it ultimately fails in humans.

  14. Gene Therapy Restores Sight in Blind Dogs

    Preclinical

    Researchers successfully restored sight in three dogs with LCA using AAV gene therapy, paving the way for human trials.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

2007-2017

Luxturna for Inherited Blindness

Researchers developed an AAV gene therapy to treat Leber congenital amaurosis (LCA), an inherited form of blindness caused by RPE65 gene mutations. After successful trials in blind dogs in 2001 and human trials beginning in 2007, the therapy dramatically improved vision in patients who had been legally blind. Twelve patients aged 8 to 46 experienced vision improvements within weeks of a single injection under the retina.

Then

FDA approved Luxturna in December 2017 as the first gene therapy for an inherited disease, priced at $425,000 per eye.

Now

Luxturna established the regulatory and reimbursement pathway for gene therapies targeting sensory loss and demonstrated AAV vectors could safely restore function to neural tissue.

Why this matters now

OTOF gene therapy follows the same technical playbook—AAV vectors delivering functional genes to restore sensory function—and faces identical challenges around cost, patient selection, and durability of response.

2014-2019

Zolgensma for Spinal Muscular Atrophy

Novartis developed Zolgensma, an AAV9 gene therapy delivering the SMN1 gene to treat spinal muscular atrophy, a neurodegenerative disease with 90% infant mortality. Clinical trials showed a single intravenous infusion dramatically improved motor function and survival in babies treated before symptom onset. Fifteen patients aged 0.9 to 7.9 months all survived and showed improved development, with the longest survivor remaining healthy at 33 months.

Then

FDA approved Zolgensma in May 2019 at $2.125 million per patient, then the world's most expensive drug.

Now

Zolgensma proved gene therapy could treat central nervous system disorders and that astronomical one-time costs could gain reimbursement if the alternative was lifelong supportive care. Shifted paradigm toward ultra-early treatment.

Why this matters now

Like Zolgensma, OTOF gene therapy shows best results in young children during critical developmental windows, raising identical questions about newborn screening, early diagnosis, treatment timing, and how to price cures for rare pediatric diseases.

1984-2000

Cochlear Implants Overcome Resistance

When the FDA approved cochlear implants for adults in 1984 and children in 1990, many in the Deaf community opposed them as cultural genocide—attempting to 'fix' deaf people rather than accepting deafness as a natural variation. The National Association of the Deaf initially opposed pediatric cochlear implantation. Parents faced difficult choices between medical intervention and Deaf culture. Over time, outcomes data showed clear benefits for early implantation, particularly for speech and language development.

Then

Adoption grew slowly amid fierce cultural debates, with many Deaf leaders viewing implants as threats to sign language communities.

Now

Cochlear implants became standard of care for severe-to-profound hearing loss, with 736,900 devices implanted globally by 2019. Deaf community adapted, many embracing both technological intervention and cultural identity.

Why this matters now

Gene therapy reignites the same cultural tensions cochlear implants faced: Is deafness a disability to cure or a difference to celebrate? Early intervention raises stakes even higher, as gene therapy in infancy could prevent children from ever entering Deaf culture.

Sources

(14)
+8
Nature Medicine ScienceDaily New England Journal of Medicine Harvard Medical School Karolinska Institutet Children's Hospital of Philadelphia Regeneron Pharmaceuticals CGTlive Fudan University Eli Lilly and Company Scientific American Advanced Science International Journal of Molecular Sciences Nature Medicine