Chardan: Sell Regeneron After Sanofi Drops Patent Infringement Bombshell By: Benzinga via Benzinga February 10, 2016 at 09:30 AM EST Regeneron Pharmaceuticals Inc (NASDAQ: REGN) shares have been trending south this year, and are down 33 percent since January ... Read More >> Related Stocks: Amgen Regeneron Pharmaceuticals Sanofi-Aventis S.A. ADR