Sensorion drops a gene therapy asset because of Regeneron

Montpellier-based Sensorion said it has filed clinical trial applications in France and Canada for SENS-601, also known as GJB2-GT, an AAV-based gene therapy designed to treat hearing loss caused by mutations in the GJB2 gene. The French medicines agency ANSM has granted the program a fast-track procedure, which Sensorion said should shorten the review period compared with the standard pathway. The company is also targeting an investigational new drug submission in the U.S. and a submission in Australia by the end of 2026.

The planned Hearconnex trial will assess the safety, tolerability and efficacy of intra-cochlear administration of SENS-601 in pediatric patients with GJB2 gene-mediated hearing loss. It will also evaluate the safety, performance and usability of Sensorion’s delivery system.

GJB2 encodes the transmembrane protein connexin 26 and plays a key role in maintaining the ionic balance required for sound transduction in the inner ear. Mutations in the gene are the most common cause of genetic congenital deafness and account for around 50% of autosomal recessive non-syndromic hearing loss, according to Sensorion. The company said SENS-601 could potentially address pediatric congenital deafness, progressive forms of hearing loss in children and early-onset severe presbycusis in adults.

Market disturbance

The decision marks a strategic pivot for Sensorion’s gene therapy pipeline. The company will stop recruiting patients in the Audiogene trial of SENS-501, its program for OTOF-related hearing loss, although it said it will continue long-term follow-up of patients already enrolled. The company said OTOF-related hearing loss is ultra-rare and that the recent availability of a gene therapy showing meaningful clinical efficacy in this indication had changed the development environment.

That reference is to Regeneron’s Otarmeni, which the FDA approved in April 2026 as the first gene therapy for genetic hearing loss. Otarmeni is indicated for patients with severe-to-profound or profound sensorineural hearing loss linked to molecularly confirmed biallelic OTOF variants, and Regeneron has said it will provide the therapy free of charge in the U.S.

Sensorion said the SENS-501 program has nevertheless created a clinical and operational foundation that can support SENS-601. The company is developing SENS-601 in collaboration with renowned French geneticist Christine Petit and her team at Institut Pasteur, Institut reConnect and Institut de l’Audition, together with Inserm and CNRS. Petit said preclinical work had shown “significant hearing restoration” after SENS-601 administration in clinically relevant animal models.

By reallocating resources to SENS-601, Sensorion said its cash runway now extends to the end of 2027, covering the planned clinical advancement of the program and the generation of first-in-human data.

Sensorion’s Euronext Paris-listed shares fell roughly 22% between Wednesday and Thursday following the update, suggesting investors focused less on the regulatory progress for SENS-601 and more on the near-term setback of ending recruitment for SENS-501.