Sensorion Advances SENS-601 Toward First-in-Human Gene Therapy for GJB2-Related Deafness
Sensorion, a French clinical-stage biotechnology company, announced on March 23, 2026, that it is advancing SENS-601 (GJB2-GT), an AAV-based gene therapy targeting mutations in the GJB2 gene, toward first-in-human clinical development. The GJB2 gene encodes connexin 26, a gap junction protein that maintains the ionic balance required for sound transduction in the inner ear. GJB2 mutations account for approximately 50% of autosomal recessive non-syndromic hearing loss, making this the single largest genetic cause of congenital deafness. Sensorion is targeting a Clinical Trial Application submission in the first half of 2026 in Europe and an IND submission to the FDA by year-end 2026. Developed in collaboration with the Institut Pasteur, SENS-601 preclinical safety, biodistribution, and efficacy data will be presented at the ASGCT annual meeting in May 2026. No trial registry listing, enrolment target, dosing schedule, or endpoint structure has been disclosed for the planned first-in-human study. (Source)
The announcement accompanied updated Audiogene trial results for Sensorion SENS-501, the company's gene therapy for otoferlin-mediated deafness (DFNB9), now in a Phase 1/2 OTOF gene therapy clinical trial. Six-month follow-up data from Cohort 2 showed sustained directional improvements in pure-tone audiometry in two of three patients treated at the higher dose, consistent with a dose-response relationship across cohorts. Across all six patients dosed in the escalation phase, no serious adverse events were reported. Sensorion is considering a third dose level and will consult regulatory authorities. The Audiogene trial enrolls children aged 6 to 31 months, with safety as the primary endpoint in the dose-escalation portion and auditory brainstem response as the primary efficacy endpoint in the expansion cohort.
Research Context
The rationale for pursuing GJB2 as a gene therapy target rests on the gene's central role in cochlear physiology and the scale of the affected population. Connexin 26 forms gap junctions between supporting cells of the cochlea, enabling potassium recycling essential for hair cell depolarization and auditory signal transduction. Loss-of-function mutations abolish this process, causing severe-to-profound hearing loss from birth. Research catalogued on AllSci confirms the high prevalence of GJB2 mutations among hearing loss cohorts and their association with cochlear implant candidacy and performance (Prevalence of Connexin 26 Mutations in Adult Cochlear Implant Candidates; Association of GJB2 Gene Mutation With Cochlear Implant Performance). Clinical experience from Sensorion's Audiogene trial for SENS-501—which has validated the company's surgical delivery platform, intra-cochlear administration, and dose-escalation framework—directly informs the SENS-601 program, providing procedural and safety data transferable to a second monogenic target.