Chardan Upgrades Regeneron Amid Relative Underperformance To Amgen Shares By: Benzinga via Benzinga February 16, 2016 at 08:33 AM EST Regeneron Pharmaceuticals Inc (NASDAQ: REGN) shares have been trending south in 2016, and are down 30 percent since January ... Read More >> Related Stocks: Amgen Regeneron Pharmaceuticals Sanofi-Aventis S.A. ADR