Outlook and future of inner ear therapy

Drug delivery to the inner ear is an ideal method to treat a wide variety of otologic conditions. A broad range of potential applications is just beginning to be explored. New approaches combine principles of inner ear pharmacokinetics with emerging technologies of drug delivery including novel delivery systems, drug-device combinations, and new categories of drugs. Strategies include cell-specific targeting, manipulation of gene expression, local activation following systemic delivery, and use of stem cells, viral vectors, and gene editing systems. Translation of these therapies to the clinic remains challenging given the potential risks of intracochlear and intralabyrinthine trauma, our limited understanding of the etiologies of particular inner ear disorders, and paucity of accurate diagnostic tools at the cellular level. This review provides an overview of future methods, delivery systems, disease targets, and clinical considerations required for translation to clinical medicine.