Researchers published updated long-term outcomes from a multicentre gene therapy trial targeting DFNB9, a hereditary deafness caused by OTOF mutations. The report in Nature (2026) describes sustained safety and efficacy signals, reinforcing the durability case for gene delivery in congenital hearing loss. The findings come as the gene therapy market increasingly shifts from early proof-of-concept toward questions of persistence of benefit, patient-relevant hearing thresholds, and broader age-range applicability. DFNB9 remains a key target because it offers a clear genetic entry point for precision therapy. Clinically, the next checkpoint is how outcomes scale across sites and patient subgroups and what monitoring and follow-up protocols will be expected as therapies move toward broader commercialization.