At least 13 biotechs and pharmas reported earnings last week. Regeneron Pharmaceuticals Inc. (NASDAQ:REGN), which markets ophthalmic drug Eylea aflibercept, gained 4% after beating the Street's consensus revenue and earnings estimates. The move equated to an additional $1.4 billion in market cap.

Two biotechs pursuing tax inversion deals - Auxilium Pharmaceuticals Inc. (NASDAQ:AUXL) and Salix Pharmaceuticals Ltd. (NASDAQ:SLXP) - each fell at least 5% last week after reporting 2Q14 EPS and revenues that missed the Street's estimates. Auxilium is merging with QLT Inc. (TSX:QLT; NASDAQ:QLTI) and plans to re-domicile in Canada, while Salix is merging with an Irish subsidiary of Cosmo Pharmaceuticals S.p.A. (SIX:COPN).