Regeneron Pharmaceuticals, Inc. has entered a definitive agreement to acquire Decibel Therapeutics, Inc., a clinical-stage biotechnology company dedicated to treatments to restore and improve hearing and balance, for a total equity value of approximately $109 million payable at closing, and a total of up to approximately $213 million if development and regulatory milestones are achieved.   Decibel and Regeneron established their initial collaboration in 2017, with an extension announced in 202...