This study intends to assess safety, tolerability, and efficacy of SENS-501 in children between the ages of 6-31 months with pre-lingual hearing loss due to a mutation in the Otoferlin gene.

It is a multicenter, adaptive open-label, non-randomized, dose-escalation, and expansion study to assess safety, tolerability, and efficacy following intracochlear administration of SENS-501.

Inclusion Criteria:

• Children (male or female) ≥ 6 to ≤ 31 months at the time of inclusion
• Severe to profound hearing loss assessed by auditory brainstem response (ABR)
• Biallelic mutation in the Otoferlin gene
• Presence of Otoacoustic emissions (OAEs)
• Documented normal cochlea and internal auditory canals
• Patients with intact vestibular function

Exclusion Criteria:

• History of chronic, acute, or major disease, or unspecified reasons, that in the opinion of the Investigator, makes the participant unsuitable for participation in the study or constitutes an unacceptable risk.
• Have been dosed in a previous gene therapy clinical trial
• Patients with a prior or current cochlear implant
• Any contraindication to the surgery determined by the surgeon or anesthesia determined by the anesthesiologist, or designee, or history of therapy known as ototoxic (e.g., cisplatin, high dose and long treatment with aminoglycosides, etc.) for an extended period (more than 2 weeks).
• Participation in any other interventional clinical trial
• Any other condition that, in the opinion of the Investigator, may compromise the safety or compliance of the participant or would preclude the participant from successful completion of the study or might interfere with the evaluation of study treatment
• Anticipated noncompliance with the protocol requirements