Repligen Corporation is a United States-based life sciences company focused on the development, production and commercialization of products used in the process of manufacturing biological drugs. The Company manufactures Protein A, a critical reagent used to manufacture monoclonal antibody-based therapeutics. It also supplies several growth factor products used to increase cell culture productivity in biomanufacturing. The Company develops and markets a series of OPUS (Open Platform User Specified) single-use chromatography columns used in the biologics purification process. In June 2014, the Company acquired the business of Refine Technology, including Refine's Alternating Tangential Flow System.