Clinical gene therapy restores hearing: a paradigm shift.

Recent breakthroughs in gene therapy for autosomal recessive deafness 9 (DFNB9) caused by OTOF mutations have transformed treatment paradigms for hereditary hearing loss (HHL). To date, eight clinical trials targeting DFNB9 have been registered in 51 centers across eight countries, demonstrating the rapid progress of gene therapy in auditory medicine. These pioneering studies establish the framework for the clinical translation of gene therapy targeting HHL. This review synthesizes progress in OTOF-related clinical trials, highlighting translational foci such as inner ear drug delivery, trial design, safety assessments, and auditory restoration outcomes. Key challenges in optimizing future therapeutic strategies - including addressing anatomical constraints, refining patient selection criteria, and standardizing outcome measures - are critically examined.