A Phase 1/2, Open-Label, Multicenter Trial With a Single Ascending Dose Cohort With Unilateral Intracochlear Injection Followed by a Bilateral Injection Expansion Cohort to Evaluate the Safety, Tolerability, and Efficacy of DB-OTO in Children and Infants With Biallelic hOTOF Mutations
Regeneron is conducting a study of an investigational new drug called DB-OTO. DB-OTO is a gene therapy that is being developed to treat pediatric and adult participants who have severe-to profound and profound hearing loss due to changes in the otoferlin gene. The purpose of this study is to: * Learn about the safety of DB-OTO * Determine how well DB-OTO is tolerated (does not cause ongoing discomfort) * Evaluate the efficacy of DB-OTO (how well DB-OTO works)
• Willingness to provide written informed consent (by at least one parent/legal guardian for pediatric participants, and with participant to provide assent, when applicable, or by the adult participant) and willingness to comply with trial protocol
• Willingness to consent to genetic testing for the participant (by at least one parent/legal guardian for pediatric participants, and with participant to provide assent, when applicable, or by the adult participant) in order to evaluate a panel of hearing loss-related genes
• Willingness to consent to vaccinations for the participant (by at least one parent/legal guardian for pediatric participants, and with participant to provide assent, when applicable, or by the adult participant) in accordance with the country-specific, age-appropriate immunization schedule, as described in the protocol
• Participant able to perform all necessary assessments to qualify for enrollment and dosing in the corresponding cohort at the time the participant or parent/legal guardian signing the informed consent form (and participant providing assent, when applicable)
• Presence of biallelic, likely pathogenic or pathogenic OTOF variants
• No clinically significant laboratory findings on clinical laboratory tests at time of Screening as described in the protocol
• Audiological Criteria:
‣ Investigator diagnoses the participant with profound sensorineural hearing loss (SNHL; \>90 dB HL) based on behavioral and physiologic measurements (ABR) of inner ear function
⁃ Outer hair cell presence is confirmed via presence of otoacoustic emissions (≥6 dBSNR) at ≥3 frequencies from 1 to 8 kHz in the ear(s) to be infused with DB-OTO. Alternatively, for participants \>24 months of age, outer hair cell presence can be confirmed via presence of the cochlear microphonic in the ear(s) to be infused with DB-OTO.
• No evidence from measures of hearing loss that show a dependence on body temperature
• From study start and for the duration of the short-term follow-up period (48 weeks): Female participants of childbearing potential and fertile males, must agree to use highly effective contraception. Female participants must agree not to become pregnant. Fertile male participants must agree not to father a child or donate sperm, for 48 weeks and in cases of early withdrawal, for at least 12 months after DB-OTO administration.