A Study of DB-OTO, an Adeno-Associated Virus (AAV) Based Gene Therapy, in Children/Infants With Hearing Loss Due to Otoferlin Mutations

Inclusion criteria

• ✓. Willingness of at least 1 parent/legal guardian to provide written informed consent (and patient to provide assent, when applicable) and willingness to comply with trial protocol; to consent to genetic testing for the patient (and patient to provide assent, when applicable) in order to evaluate a panel of hearing loss-related genes; and to consent to vaccinations for the patient (and patient to provide assent, when applicable) in accordance with the country-specific pediatric immunization schedule as described in the protocol
• ✓. Patient is aged \<18 years and able to perform all necessary assessments to qualify for enrollment and dosing in the corresponding cohort at the time the parent/legal guardian signing the informed consent form (and patient 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 patient 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 injected with DB-OTO. Alternatively, for children \>24 months to \<18 years of age, outer hair cell presence can be confirmed via presence of the cochlear microphonic in the ear(s) to be injected with DB-OTO.
• ✓. No evidence from measures of hearing loss that show a dependence on body temperature

Exclusion criteria