Regeneron Pharmaceuticals has agreed to acquire Decibel Therapeutics, a clinical- stage biotechnology company specializing in therapies to restore and improve hearing and balance, for an up-front payment of $109 million. The two companies have collaborated since 2017 on three gene therapy programs targeting different forms of congenital, monogenic hearing loss. These include DB-OTO, an investigational cell- selective, adeno-associated virus gene therapy, currently in clinical trials. It is designed to provide physiological hearing to individuals with profound congenital hearing loss caused by mutations of the otoferlin gene. Milestone payments to Decibel associated with DB-OTO could bring the value of the deal to $213 million.