Biotech Stocks Today: FDA Fast Track Wins, PDUFA Delays and Deal Flow Move GLUE, ALDX, ADAG, PVLA as XBI and IBB Slide
Updated: Tuesday, December 16, 2025 | Early afternoon ET (U.S. stock market) Biotechnology stocks are delivering a classic split-screen session in the U.S. market today: biotech ETFs are slipping, but a handful of single-name biotech movers are swinging sharply on FDA updates, clinical data, and year-end dealmaking. By early afternoon in New York (based on the latest available quotes at the time of writing), the SPDR S&P Biotech ETF (XBI) was down about 1.1%, while the iShares Biotechnology ETF (IBB) was also off about 1.1%—both lagging the broader tape. That “ETFs down, catalysts up (or down) even more” pattern is a big part of what makes biotech stocks today a headline