Mitsubishi Chemical, a chemical maker, agreed to acquire a remaining stake in Mitsubishi Tanabe Pharma, a pharmaceuticals company, for $4.5bn. The chemical maker already held more than 56% of shares in Mitsubishi Tanabe. The Osaka-based pharma company was the product of a 2007 merger between Mitsubishi Pharma and Tanabe Seiyaku. It focuses on autoimmune, diabetes, renal and central nervous system treatments.