Supernus Pharmaceuticals has completed its $400 million acquisition of Adamas Pharmaceuticals. The company has developed GOCOVRI, one of two Adamas drugs approved by the FDA for the treatment of Parkinson's disease. If GOCOVRI sales reach $375 million by 2025, Supernus will pay an additional $50 million. Potential synergies in the first year of the deal could be between $60 million and $80 million.