This study aims to demonstrate that the investigational drug AUT00063 is effective and safe in the treatment of age-related hearing loss.

Reduced activity at certain sites in the brain (called "voltage-gated potassium channels") has been linked to hearing problems, like age-related loss of hearing or tinnitus (a 'ringing' or buzzing noise in the ears).

AUT00063 is an experimental new medicine that enhances the action of these specific channels and so may treat the brain component of these hearing problems.

The main purpose of this study is to try to demonstrate an improvement in a speech-in-noise deficit after 4 weeks of treatment with the study drug versus the placebo (dummy drug which does not contain the drug). Subjects will undergo a safety follow-up after the treatment period.

Safety and efficacy will be determined by looking at a number of assessments (physical examinations, blood sampling, hearing assessments, questionnaires, etc.).

The amount of drug in the blood will also be measured. It is expected that around 70 people (at least 35 in each arm) with age-related hearing loss may take part in the study. The study participants will be recruited at around 13 sites in the USA.

• Be between ages 50-89 years old
• American-English speaking
• Have difficulty hearing speech in a noisy environment
• No recent history of middle ear disease
• No severe insomnia, major depressive disorders, severe anxiety or post-traumatic stress disorder
• Not a current or previous user of hearing aids. You are eligible if you were noncompliant and stopped wearing a hearing aid device >6 months earlier for intermittent use or >3 years if you were a full-time consistent user of hearing aid devices
• Not be dependent on alcohol or drugs
• Have not participated in another research study within 30-days
• If female, you must confirm to be non child bearing (post-menopausal for at least 12-months or surgically sterile)
• If male, you must confirm to use a barrier method (condom)
• Not be a professional musician
• No history of important cardiac, endocrine, pulmonary, neurologic, psychiatric, hepatic, renal, hematologic, immunologic, or other major disease deemed clinically significant by the study doctor

While you are in the study, you must:

• Follow the instructions you are given
• Come to the study centre for all visits with the study doctor or study staff
• Answer the telephone at the scheduled date and time for the 2 telephone calls
• Tell the study doctor or study staff about any changes in your health or the way you feel
• Tell the study doctor or study staff if you want to stop being in the study at any time
• Bring your Diary to each visit
• Not eat or drink anything containing Grapefruit beginning 7-days before Baseline visit (Visit 3, Day 1) until the end of the study
• Use sun screen if you plan to sunbathe
• Not use headphones or headsets at high volume
• Not use hearing aids or devices at any time during the study