Sensorion Names GJB2 Hearing Loss Therapy as Lead Program; Ends OTOF Trial

Sensorion has selected SENS-601—the company’s investigational gene therapy for GJB2-related hearing loss—as its new lead gene therapy candidate after filing clinical trial applications in Canada and France and receiving a Fast Track review pathway from France’s medicines agency.

The Montpellier, France- and Cambridge, Massachusetts-based biotechnology company said in a press release that the planned Hearconnex study will evaluate the safety, tolerability, and early efficacy of SENS-601 when delivered directly into the cochlea of pediatric patients with hearing loss caused by GJB2 mutations. The trial will also assess the safety, performance, and usability of Sensorion’s proprietary delivery system.

GJB2-related hearing loss is one of the largest single genetic categories in childhood deafness. While exact prevalence varies by population, GJB2 variants are estimated to cause roughly 15-20% of congenital hearing loss overall and about half of autosomal recessive nonsyndromic cases.

There is currently no approved gene therapy for GJB2-related hearing loss. Sensorion says its SENS-601 program could potentially apply to three groups: infants born with GJB2-related deafness, children with progressive forms of hearing loss, and some adults with early-onset severe presbycusis tied to GJB2 mutations.

Sensorion expects to submit an Investigational New Drug application to the U.S. Food and Drug Administration (FDA), along with an additional regulatory filing in Australia, by the end of 2026. The company said the new clinical submissions followed pre-submission discussions with regulators and that it has “high confidence” in the scientific and regulatory package supporting the program. The Fast Track in France reportedly offers a significantly shorter assessment period than the standard pathway.

SENS-601 is being developed with scientific partners at the Institut Pasteur, Institut reConnect, Institut de l’Audition, Inserm, and CNRS. The therapy uses an adeno-associated virus platform and is designed to address hearing loss linked to GJB2, a gene that plays an important role in maintaining the ionic environment needed for normal auditory signaling in the inner ear.

Discontinuation of SENS-501 for OTOF-related Hearing Loss

As part of the same announcement, Sensorion said it will discontinue clinical development of SENS-501, the company’s gene therapy candidate for OTOF-related hearing loss, and will end recruitment in its Audiogene Phase 1/2 trial. It will continue long-term follow-up for patients already enrolled, in line with regulatory requirements.

The decision likely reflects a combination of market and resource-allocation factors rather than indicating the relative success/failure of the OTOF program. Previous updates from Sensorion reported that SENS-501 was generally well tolerated and showed early signs of hearing improvement in treated children.

However, OTOF-related hearing loss is an “ultra-rare” condition, and the competitive environment has quickly changed.

Although both the OTOF and GJB2 programs target inherited forms of childhood hearing loss, GJB2 represents a much larger potential patient demographic. GJB2 is widely regarded as the most common genetic cause of congenital nonsyndromic sensorineural hearing loss in many populations, with variants accounting for about half of autosomal recessive nonsyndromic cases. By contrast, OTOF-related hearing loss is considered ultra-rare, with variants in the gene estimated to account for roughly 2-8% of inherited, nonsyndromic hearing loss cases.

Additionally, an OTOF gene therapy has already reached the U.S. market. In April, Regeneron received FDA accelerated approval for Otarmeni, formerly known as DB-OTO, making it the first approved gene therapy for OTOF-related hearing loss. The therapy is approved for eligible children and adults with severe-to-profound or profound sensorineural hearing loss caused by confirmed OTOF variants, preserved outer hair cell function, and no prior cochlear implant in the treated ear. Regeneron also announced that it would provide Otarmeni at no cost to clinically eligible patients in the United States, though administration-related costs may still depend on insurers and providers.

Fred Chereau, Sensorion’s newly appointed CEO, said the company’s work on Audiogene has provided a clinical and operational foundation that can now support SENS-601.

Christine Petit, professor at Institut Pasteur–Institut reConnect/Institut de l’Audition and professor emeritus at the Collège de France, said in a press statement: “GJB2 mutations are the most common cause of genetic hearing loss, and the work we have conducted with Sensorion over many years has built a strong foundation for what I believe will be a pivotal program. We have generated extremely robust, comprehensive data demonstrating significant hearing restoration after SENS-601 administration, in clinically relevant animal models developed in our laboratories. I look forward to continuing this collaboration and to the prospect of providing patients with a meaningful therapeutic option. The scientific and clinical advances of Audiogene are directly guiding and increasing our confidence in SENS-601, confirming the very promising results my team first obtained in mice back in 2019. The rigor with which the multidisciplinary teams from the Institut Pasteur-Institut reConnect/Institut de l’Audition, Necker Enfants-Malades Hospital (AP-HP), the Fondation Pour l’Audition and Sensorion have conducted this program is a credit to everyone involved.”

By narrowing its gene therapy focus to SENS-601, Sensorion said it is extending its cash runway through the end of 2027. It reports that the additional time should support clinical advancement of the GJB2 program and the generation of first-in-human data.

For hearing healthcare, the recent move highlights how quickly genetic hearing loss therapies are moving from proof-of-concept experiments toward clinical and regulatory competition. OTOF has already produced the first approved hearing restoration gene therapy, while GJB2 may represent the next major test of whether these approaches can be expanded to more common forms of inherited hearing loss.

Sensorion’s pipeline also includes SENS-401, a clinical-stage small molecule studied in Phase 2 trials for several hearing-related issues, including cisplatin-related ototoxicity, cochlear implant hearing preservation, and sudden sensorineural hearing loss (SSNHL).