Decibel Therapeutics announced that the European Medicines Agency (EMA) Committee on Orphan Medicinal Products (COMP) has issued a positive opinion on orphan drug designation for DB-OTO, Decibel's lead gene therapy product candidate designed to provide durable, high quality, physiological hearing to individuals with profound, congenital hearing loss caused by mutations of the otoferlin gene. This opinion was adopted by the European Commission (EC). Orphan drug designation is granted by the EC for medicines in development to treat rare conditions affecting no more than five in 10,000 people in the European Union, provided there is no other satisfactory treatment option or the medicine can be of significant benefit to those affected by a specific condition.

Medicines that are granted orphan drug designation by the EC qualify for financial and regulatory incentives including protocol assistance, possible exemptions or reductions in certain regulatory fees, and, if approved for marketing, ten years of market exclusivity in the European Union. DB-OTO received Orphan Drug and Rare Pediatric Disease designations from the U.S. Food and Drug Administration in 2021. Currently, there are no approved pharmacologic treatment options for people with hearing loss caused by genetic mutations of otoferlin.