Image source: Getty Images.This has been a rough year for biotech investors. The market cap-weighted iShares Nasdaq Biotechnology ETF (NASDAQ: IBB) is down about 23% year to date, and some companies have been hit even harder. Shares of bluebird bio (NASDAQ: BLUE), Celldex Therapeutics, Inc. (NASDAQ: CLDX), and Ionis Pharmaceuticals, Inc.