Shares of Regeneron Pharmaceuticals, Inc. (REGN) have dropped 15.5% in the year so far compared with the industry’s decline of 6.3%.The stock has underperformed the sector and the S&P 500 Index during this timeframe. While the stock’s performance was encouraging at the onset of 2024, challenges for lead drug Eylea have dampened investors’ sentiment of late.Regeneron Underperforms Industry, Sector & S&P 500Image Source: Zacks Investment ResearchEylea Sales Decline Hampers REGN's Ophthalmology UnitEylea is an ...