SPI-1005 in Adults Receiving Cochlear Implant

Inclusion Criteria: * Adults who are ≥18 years of age at time of consent. * Post-lingual, bilateral, moderate to profound sensorineural hearing loss scheduled to receive a long electrode array (FLEX26 or greater) from MED-EL Cochlear Implant Systems into one ear. * Air conduction thresholds (decibel hearing loss, dB HL) at baseline in the ear scheduled to receive the cochlear implant: * ≤70 dB HL at 125, 250, and 500 Hz; AND * ≥70 dB HL at 2000, 4000, and 8000 Hz. * Type A (including As and Ad) tympanogram at baseline in the ear scheduled to receive the cochlear implant. * Willing and able to provide informed consent and to perform all behavioral tests as specified per-protocol, including pre-specified reproductive requirements. Exclusion Criteria: * Current, or within 60 days prior to study consent, use of IV ototoxic medications such as chemotherapy including cisplatin, carboplatin, or oxaliplatin; aminoglycoside antibiotics including gentamicin, amikacin, tobramycin, kanamycin, or streptomycin; or loop diuretics including furosemide. * Participation in another investigational drug or device study within 90 days prior to study consent. * Female patients who are pregnant or breastfeeding. * Moderate or severe hepatic impairment using Child-Pugh Score (\>6 points). * No measurable air conduction response at three or more consecutive test frequencies (e.g., 2000, 4000 and 8000 Hz) at baseline in the ear scheduled to receive the cochlear implant. * No middle ear mobility (Type B tympanogram) or abnormal middle ear pressure (exceeds -150 to +50 range).