At least 20 biotechs and pharmas reported earnings last week. Regeneron Pharmaceuticals Inc. (NASDAQ:REGN) dropped 8%, losing more than $2 billion in market value, after posting EPS and revenues that disappointed Wall Street analysts. The biotech did raise its 2013 revenue guidance for macular degeneration drug Eylea aflibercept to $1.3-$1.35 billion from $1.25-$1.33 billion, and announced plans to submit an sBLA to FDA for Eylea to treat diabetic macular edema (DME) this year, about one year ahead of the company's previously announced timeframe.

Dendreon Corp. (NASDAQ:DNDN), which markets prostate cancer therapy Provenge sipuleucel-T, fell 26% after posting EPS and revenues that missed analyst consensus estimates. The biotech said it does not expect to see enough of a sales increase in 2H13 to meet its goal of growing Provenge year-over-year.