Auris Medical is developing Keyzilen® for the treatment of acute inner ear (peripheral) tinnitus following traumatic cochlear injury or otitis media (middle ear infection). Keyzilen® contains Esketamine hydrochloride, an N-Methyl-D-Aspartate (NMDA) receptor antagonist, formulated in a biocompatible and fully biodegradable gel. It is administered in one treatment cycle, comprising three intratympanic injections over 3 to 5 days into the middle ear. From there the drug diffuses through the so-called round window membrane into the cochlea.
Acoustic trauma and other insults to the inner ear may trigger increased levels of extra-cellular glutamate, which in turn cause excessive activation of cochlear NMDA receptors. This process results in damage or killing of sensory cells and is thought to be responsible for abnormal spontaneous "firing" of auditory nerves, which may be perceived as tinnitus. Under normal circumstances, the NMDA receptors are thought to play no role in fast excitatory neurotransmission, respectively normal hearing. Keyzilen® is blocking cochlear NMDA receptors to suppress the aberrant excitation of the auditory nerve that is perceived as tinnitus.
Keyzilen® is currently in Phase 3 clinical development.