The purpose of the study is the evaluation of the therapeutic benefit of intratympanic AM 101 injections in comparison to placebo in the treatment of persistent acute inner ear tinnitus following acute sensorineural hearing loss.

Tinnitus may seriously impact the ability to sleep, relax, or to concentrate, or lead to tiredness, irritation, nervousness, despair, frustration, or depression, thus severely impacting the quality of life and health of the affected person. To date, there exists no pharmaceutical treatment for persisting tinnitus.

Non-clinical studies with AM-101 have shown that the inhibition of cochlear NMDA receptors is successful in suppressing tinnitus without affecting normal glutamate neurotransmission respectively hearing function. In particular, it could be demonstrated that local administration of AM-101 in a single dose resulted in a complete suppression of tinnitus induced by acute acoustic trauma without any relapse thereafter.

Inclusion Criteria:

• Persistent tinnitus following acute acoustic trauma, sudden deafness, or acute otitis media with onset less than three months ago (i.e. acute tinnitus)
• Tinnitus provoking incident of acute acoustic trauma, sudden deafness or acute otitis media is documented by audiogram and medical report and at onset resulted in an inner ear hearing loss of at least 15 dB in two adjacent frequencies
• Minimum Masking Level (MML) of at least 5 dB SL
• Age ≥ 18 years and ≤ 65 years
• Negative pregnancy test for women of childbearing potential
• Willing and able to attend the on-study visits
• Must be able to read and understand the relevant study documents
• Written informed consent before participation in the study

Exclusion Criteria:

• Tinnitus that is not completely maskable
• Fluctuating tinnitus
• Intermittent tinnitus
• Meniere's Disease
• Acute or chronic otitis media or otitis externa
• Any ongoing therapy known as potentially tinnitus-inducing (e.g. aminoglycosides, cisplatin, loop diuretics, high doses of aspirin, quinine etc.)
• Any drug-based therapy for inner ear hearing loss that is ongoing or was performed in the past 2 weeks, e.g. prednisolone, dexamethasone, pentoxifylline, betahistine, diazepam, carbamazepine, sodium valproate and antidepressants
• Concomitant use of any other NMDA receptor antagonist (e.g. memantine, dextromethorphan, ifenprodil)
• Any ongoing or planned concomitant medication for the treatment of tinnitus until 90 days after study drug application
• History or presence of drug abuse or alcoholism
• Any clinically relevant respiratory, cardiovascular, neurological (except vertigo), or psychiatric disorder
• Known hypersensitivity, allergy or intolerance to the study medication or any history of severe abnormal drug reaction
• Women who are breast-feeding, pregnant or who plan a pregnancy during the trial
• Women of childbearing potential who declare being unwilling or unable to practice contraception such as hormonal contraceptives, sexual abstinence or intercourse with a vasectomised partner
• Concurrent participation in another clinical trial with an investigational drug or participation in another clinical trial with an investigational drug within 30 days prior to study entry
• Any drug-based therapy for otitis media that is ongoing or was performed in the past 2 weeks