FX-322 in Adults With Acquired Sensorineural Hearing Loss

Inclusion Criteria:

1. Subject has read and voluntarily signed the Informed Consent Form (ICF) after allquestions have been answered and prior to any study-mandated procedure.
2. Adult aged 18-65 years inclusive at Screening.
3. Documented medical history consistent with acquired, adult onset, sensorineuralhearing loss associated with noise-induced SNHL (NIHL) or idiopathic sudden SNHL (SSNHL) (documented audiogram at least 6 months prior to screening required).
4. A pure tone average at the Screening Visit of 35-85 dB at 500Hz, 1000Hz, 2000Hz, and 4000Hz in the ear to be injected.
5. Ability to communicate well with the Investigator and is willing to comply with andcomplete all the study procedures.
6. Female subjects must be of non-childbearing potential or will need to utilize twomethods of highly effective contraception during the study participation (e.g.hormonal contraception and condom or an intrauterine device and condom) or remainabstinent. Male subjects should use condoms with spermicide during the course of thestudy or remain abstinent. Subjects should not donate sperm or ova during the studyperiod.
7. Have met additional masked criteria as determined by the Electronic Data Capturesystem.

Exclusion Criteria:

1. Subject has previously been randomized in a FX-322 clinical trial.
2. Perforation of tympanic membrane or other tympanic membrane disorders that wouldinterfere with the delivery and safety assessment of an intratympanic medication orreasonably be suspected to affect tympanic membrane healing after injection in studyear. This includes a current tympanostomy tube.
3. Any conductive hearing loss of greater than 15 dB at a single frequency or greaterthan 10dB at two or more contiguous octave frequencies in the study ear at theScreening visit.
4. Active chronic middle ear disease or a history of major middle ear surgery, as anadult, in the ear to be injected.
5. Subject has had an intratympanic injection in either ear within 3 months of thescreening visit.
6. Evidence of or previous diagnosis of auditory neuropathy, traumatic brain injury, "central" hearing loss, or genetic hearing loss.
7. History of chronic, recurrent clinically significant vestibular symptoms.
8. History of bilateral sudden sensorineural hearing loss or recurrent suddensensorineural hearing loss.
9. History of clinically significant systemic autoimmune disease (e.g. rheumatoidarthritis, Sjogren's syndrome, multiple sclerosis, psoriasis).
10. History of head or neck radiation, treatment, or exposure to platinum basedchemotherapy drugs or aminoglycosides.
11. Exposure to another investigational drug within 28 days prior to screening visit.
12. Evidence of any active or chronic disease or condition that could interfere with, orfor which the treatment of might interfere with, the conduct of the study, or thatwould pose an unacceptable risk to the subject in the opinion of the investigatorfollowing a detailed medical history, physical examination, and vital signs (systolicand diastolic blood pressure, pulse rate, body temperature).
13. Positive urine pregnancy test or breast-feeding.
14. Any known factor, condition, or disease that, in the view of the Investigator, mightinterfere with treatment compliance, study conduct or interpretation of the results.