[dzhu]

Actually, they DID collect clinical response data even though it was a Phase Ib trial. Specifically, as the NYT piece mentions, they measured both cognitive function (via the mini-mental state exam aka MMSE and the clinical dementia rating scale aka CDR) and plaque removal (using one of Lilly's imaging agent) in relation to dosage. The data shows consistently improving cognitive function and plaque removal as dosage increases (albeit at the cost of additional side effects).

Now this is certainly atypical for Phase 1b data but it does (to some extent) justify Biogen increasing in almost $10B in market cap. In fact, the Phase 1b data is compelling enough that Biogen is going straight to Phase III trials.

While it is healthy to be skeptical about early trial results and subsequent market movement, I think it's clearly misplaced here.