Proteon Therapeutics (Waltham, MA) a clinical-stage biopharmaceutical company focused on a recombinant human elastase designed to improve arteriovenous fistula surgery outcomes in patients requiring chronic hemodialysis, closed on $12M, bringing the total Series B financing to $50M. Participants include Bessemer Venture Partners, Devon Park Bioventures, MPM Bio, Vectis Healthcare & Life Science Fund, TVM Capital, Skyline Ventures, Prism Venture Works, and Intersouth Partners.