Biogen Idec Inc. (NASDAQ:BIIB) lost about $1.1 billion in market cap last week even as it reported positive Phase III data for its recombinant Factor VIII product for hemophilia A. Investors looking for a once-a-week dosing advantage may have felt the data don't provide a strong enough reason for patients to switch from marketed products.

On Wednesday, Biogen Idec and partner Swedish Orphan Biovitrum AB (SSE:SOBI) reported data from the Phase III A-LONG trial showing that rFVIIIFc led to overall