Primary Objective To compare the efficacy of a single course of IT Exo-Dex versus conventional IT dexamethasone and exosome vehicle alone, as measured by the mean change in pure-tone average (PTA; 0.5, 1, 2, 4 kHz) from baseline to the 4-week post-treatment endpoint.
Secondary Objectives
1. To determine the safety and tolerability profile of IT Exo-Dex.
2. To compare the rate of hearing recovery (defined as \>10 dB improvement in PTA or recovery to within 10 dB of contralateral ear) among the three treatment groups at 1, 4, and 12 weeks.
3. To assess changes in auditory function via Auditory Brainstem Response (ABR) thresholds and Otoacoustic Emissions (OAEs).
4. To characterize the pharmacokinetics and inner ear biodistribution of Exo-Dex using advanced imaging modalities (e.g., MRI with exosome-contrast agents in a sub-study cohort if applicable).