Additional Study Information: Acute inner ear hearing loss is the sudden onset of hearing loss, usually in one ear, without any known cause. Acute hearing loss can permanently destroy some of the hair cells (that govern the sense of hearing) and / or hearing nerve in the inner ear.The drug AM-111 has been developed to protect the hearing cells and nerve following sudden inner ear hearing loss. In animal experiments, AM-111 prevented/reduced death of hair cells (in the inner ear) and thus permanent hearing loss. In addition, AM-111 was found to reduce inflammation in the inner ear, which could also improve restoration of normal hearing. For AM-111 to be effective, the drug should be administered as soon as possible after the occurrence of sudden hearing loss, in order to protect the cells at risk of cell death. The protected cells are thereby able to recover in the days and weeks following hearing loss and to continue carrying out their function.