At least 20 biotechs and pharmas reported earnings last week. Alexion Pharmaceuticals Inc. (NASDAQ:ALXN) was up 19%, adding nearly $5 billion in market value last week, after beating the Street's revenue and EPS estimates. The company, which markets rare blood disorder drug Soliris eculizumab, also guided to a lower 2014 non-GAAP tax rate than had been modelled by analysts.

Fellow large-cap biotech Celgene Corp. (NASDAQ:CELG) lost $3.8 billion in market value last week. The company announced EPS that missed the consensus estimate and 2014 EPS and revenue guidance below analyst estimates. Also last week, researchers from Memorial Sloan Kettering Cancer Center questioned the risk-benefit profile of Celgene's Abraxane nab-paclitaxel in comparison to the added cost of its use in pancreatic cancer patients in a letter to the editor in the New England Journal of Medicine. Celgene also disclosed that FDA accepted for review an application for Otezla apremilast to treat moderate to severe psoriasis, with a Sept. 23 PDUFA date (see B12).