Restoring hearing to deaf children with gene therapy

How far are we from restoring hearing to deaf children with gene therapy?

Gene therapy that adds a working copy of the OTOF gene has restored hearing in small groups of children whose deafness is caused by faults in both copies of that gene. Trials published between 2024 and 2025 reported hearing gains in most treated children. On 23 April 2026 the FDA granted accelerated approval to Otarmeni (lunsotogene parvec) for severe-to-profound and profound hearing loss linked to biallelic OTOF variants. The studies are small, follow-up is short, and the approval depends on post-marketing data that Regeneron must still collect and submit.

AI illustration · Illustrative scene, not a photograph of the specific device or experiment.
WHERE WE AREPilots

Close. Early pilots are running in the real world.

Hearing gains have been shown in small trials, and the FDA has approved one therapy, but only for a defined group of patients and under accelerated approval that depends on confirmatory data. Routine use across many patients has not been shown in the sources reviewed, and no gene therapy for another cause of deafness has been shown to reach human testing in those sources. The stage is therefore pilot, not scaling.

The tech tree

Everything recorded on Vrulum that this future needs, oldest foundations at the top and the goal at the bottom. Lines show what each step requires.

What it takes: Restoring hearing to deaf children with gene therapy Unlocked Being researched Locked
  1. 2004Cochlear implantsCommercial Unlocked.
  2. 2024Gene therapy for inherited deafnessPilot and early commercial Unlocked.
  3. 2025In vivo gene editingResearch and prototypes Being researched.
  1. 2024Single-arm trial in children with OTOF deafnessDone Unlocked.
  2. 2024Both ears treated in an interim analysisDone Unlocked.
  3. 2025Larger first-in-human study of DB-OTODone Unlocked.
  4. 2026FDA accelerated approval of OtarmeniDone Unlocked.
  5. 2026CHORD trial results reported with the approvalIn progress Being researched.
  6. Date not recordedPost-marketing data submitted to the FDANot started Locked.
  7. Date not recordedHearing durability beyond 48 weeksNot started Locked.
  8. Date not recordedGene therapy for another cause of inherited deafness in human trialsNot started Locked.
  1. GoalRestoring hearing to deaf children with gene therapyGoalRequires: Gene therapy for inherited deafness, In vivo gene editing, Cochlear implants, Single-arm trial in children with OTOF deafness, Both ears treated in an interim analysis, Larger first-in-human study of DB-OTO, FDA accelerated approval of Otarmeni, CHORD trial results reported with the approval, Post-marketing data submitted to the FDA, Hearing durability beyond 48 weeks, Gene therapy for another cause of inherited deafness in human trials. Locked.

The road so far

4 of 8 steps done, 1 in progress.

  1. Done · 24 Jan 2024Single-arm trial in children with OTOF deafness

    Lv and colleagues reported a single-arm trial of AAV1-hOTOF in six children with autosomal recessive deafness 9. Five of the six recovered hearing, with 40 to 57 dB reductions in average ABR thresholds at 0.5 to 4.0 kHz. The abstract, read through Europe PMC, reports no serious adverse events. The trial had no control group. [1]

  2. Done · 5 Jun 2024Both ears treated in an interim analysis

    Wang and colleagues reported an interim analysis of five children treated in both ears. All five had bilateral hearing restoration. The authors describe the results as preliminary and the trial as ongoing. The most common adverse events were raised lymphocyte counts and raised cholesterol, and no serious adverse events occurred. [2]

  3. Done · 12 Oct 2025Larger first-in-human study of DB-OTO

    The NEJM report on DB-OTO, a dual adeno-associated virus gene therapy, treated 12 children with profound deafness by infusion into the cochlea. At week 24, 9 of 12 (75%) reached the primary endpoint of an average hearing threshold of 70 dB HL or less, and the key secondary endpoint of an auditory brainstem response of 90 dB nHL or less. The report recorded 67 adverse events, none of which led to discontinuation of treatment. [3]

  4. Done · 23 Apr 2026FDA accelerated approval of Otarmeni

    The FDA granted accelerated approval to Otarmeni for severe-to-profound and profound sensorineural hearing loss associated with biallelic OTOF variants. A news report says the supporting clinical data come from the Phase 1/2 CHORD trial and show meaningful hearing improvement. The report does not state the timepoint. Approval is conditional on additional post-marketing data. [4][5]

  5. In progress · 24 Apr 2026CHORD trial results reported with the approval

    A news report on the approval gives 16 of 20 treated participants meeting the 70 dB HL endpoint and 14 meeting the 90 dB ABR endpoint. These figures have not been checked against a full trial publication. They differ in size from the 9 of 12 week-24 result in the NEJM report, and the news report does not explain the difference. The report also says 48-week follow-up suggests a durable effect. [5]

  6. Not startedPost-marketing data submitted to the FDA

    Regeneron is required to collect and submit additional post-marketing data as a condition of the accelerated approval. The sources reviewed do not say when this will be submitted or what it will contain. [5]

  7. Not startedHearing durability beyond 48 weeks

    The reported 48-week follow-up suggests a durable effect, but no full publication with longer follow-up was found in the sources reviewed. [5]

  8. Not startedGene therapy for another cause of inherited deafness in human trials

    The trials reviewed all target OTOF. No gene therapy for another inherited cause of deafness was shown to be in human trials in the sources reviewed.

Why it matters

Before these therapies, the main treatments for deafness were devices such as hearing aids and cochlear implants, which help children hear but do not repair the cause. A therapy that restores the signal inside the inner ear would target the underlying gene fault. Early results give evidence on safety and effect in children, which may shape how other single-gene forms of deafness are studied.

What stands in the way

  • Only a small number of children have been reported in published studies, and none of the studies had a randomised control group.
  • The trials used different endpoints, vector regimens and follow-up periods, so their results cannot be compared directly.
  • The approved indication covers only biallelic OTOF variants, so most other forms of deafness fall outside it.
  • Hearing durability beyond 48 weeks is not yet established in the sources reviewed.
  • Delivery is surgical, and the sources reviewed did not give procedure-related safety data.
  • Long-term access and cost beyond Regeneron's announced free offer in the United States are not clear.

Signals to watch

  • Post-marketing data submitted to the FDA for Otarmeni, and what it shows.
  • A full publication of the CHORD trial, so that its figures can be checked against the NEJM report.
  • Hearing results reported beyond 48 weeks.
  • A gene therapy for another inherited cause of deafness entering human trials.
  • Regulatory decisions outside the United States.

Sources

  1. peer reviewed paper
    AAV1-hOTOF gene therapy for autosomal recessive deafness 9: a single-arm trial
    The Lancet, 24 Jan 2024.
  2. peer reviewed paper
    Bilateral gene therapy in children with autosomal recessive deafness 9: single-arm trial results
    Nature Medicine, 5 Jun 2024.
  3. peer reviewed paper
    DB-OTO Gene Therapy for Inherited Deafness
    Vassili Valayannopoulos. New England Journal of Medicine, 12 Oct 2025.
  4. review article
    Lunsotogene Parvec: First Approval
    Drugs, 4 Aug 2026.
  5. news
    FDA Approves Otarmeni, First Gene Therapy for Inherited Hearing Loss
    American Society of Gene & Cell Therapy, 24 Apr 2026.

Last reviewed 21 Oct 2026.