Efficacy and Safety of AM-111 as Acute Sudden Sensorineural Hearing Loss Treatment (ASSENT)

Inclusion Criteria:

1. Unilateral idiopathic sudden sensorineural hearing loss (ISSNHL) with onset within 72 hours prior to study treatment;
2. Mean hearing threshold of equal to or worse than (≥) 60 dB averaged across those 3 contiguous air conduction audiometric pure tone frequencies that show the highest mean hearing loss compared with the unaffected contralateral ear or, in case of history of asymmetric hearing, corresponding values from a pre-existing audiogram for the affected ear not older than 2 years prior to the ISSNHL incident (defined as "pure tone average", PTA);
3. Mean hearing loss of equal to or worse than (≥) 40 dB averaged across the air conduction thresholds at the pure tone average frequencies compared with the unaffected contralateral ear or, in case of history of asymmetric hearing, corresponding values from a preexisting audiogram for the affected ear not older than 2 years prior to the ISSNHL incident;
4. Age ≥ 18 years on the day of screening;

Exclusion Criteria:

1. Bilateral ISSNHL;
2. Acute hearing loss from noise trauma, barotrauma or head trauma;
3. Air-bone gap greater than 20 dB at the average of 3 contiguous test frequencies below 4 kHz, when the air-bone gap is measurable;
4. History of autoimmune hearing loss, radiation-induced hearing loss, endolymphatic hydrops or Menière's disease in either ear;
5. History of chronic inflammatory or suppurative ear disease or cholesteatoma in the affected ear;
6. Current evidence or history of acoustic neuroma or other retrocochlear damage in the affected ear;
7. History of otosclerosis in the affected ear;
8. Suspected perilymph fistula or membrane rupture in the affected ear;
9. Congenital hearing loss;
10. History of ISSNHL in the past 2 years;
11. Otitis media or otitis externa that is ongoing or ended within 7 days prior to study treatment;