Efficacy of SENS 401 in Subjects With Severe or Profound Sudden Sensorineural Hearing Loss

Patients will receive the study drug (SENS-401 or placebo) in the form of tablets by mouth, twice a day (3 tablets in the morning and 3 tablets in the evening), during the first 4 weeks after randomization.

SENS-401 is an investigational medicinal product. It belongs to a family of drugs known as "5 HT3 antagonist".

The main criteria for inclusion:

• Male or female aged at least 18 years old
• Patients with unilateral idiopathic sudden sensorineural hearing loss or unilateral/bilateral acute acoustic trauma leading to sudden sensorineural hearing loss.
• Patients with sudden hearing loss with onset within 96 hours prior to prior to first study drug intake.
• Patients under highly effective contraception

The main criteria for exclusion:

• Bilateral idiopathic hearing loss
• Fluctuating hearing loss
• History of asymmetric hearing (>20 dB difference between ears) to the best knowledge of the patient
• Severe hearing loss (>90 dB) associated with unilateral (ipsilateral) complete vestibular loss.
• History of Ménière's disease, autoimmune hearing loss, radiation-induced hearing loss, acoustic neuroma (schwannoma), otosclerosis, suspected perilymph fistula or membrane rupture, suspected retro-cochlear lesion, or barotrauma
• Previous SSNHL in the affected ear within the past 6 weeks
• Complete loss of peripheral vestibular function on the affected side
• Any drug-based therapy for inner ear hearing loss that is ongoing or was performed in the past 6 weeks (except oral corticosteroids)
• Any ongoing or planned concomitant medication for the treatment of tinnitus until 6 weeks after administration.
• Any therapy known as ototoxic (e.g. aminoglycosides, cisplatin, loop diuretics, quinine etc.) at the current time or in the past 6 months or planned in the coming 3 months.
• Acute or chronic otitis media or otitis externa terminated less than 7 days
• Prior ear surgery of any kind (except ventilating tubes), or cochlear implants
• Known history of, or concomitant severe hepatic, gastrointestinal, cardiovascular, respiratory, neurological (except vertigo or tinnitus), hematological, renal, dermatological or psychiatric disease or substance abuse
• Neurological disorders including stroke, demyelinating disease, brain stem or cerebellar dysfunction within the last 3 months.
• Treatment with any investigational agent within 4 weeks or any past treatment with azasetron or with 5-HT3 antagonists, or any prior or planned treatment by antidepressant treatment containing serotoninergic agents.
• Patients with either a history of significant arrhythmia, or a history of conditions known to increase the proarrhythmic risk (e.g., congestive heart failure, long QT Syndrome, hypokalemia etc...).