On the downside, if Biogen gets away with approval for Alzheimer, then our path to approval based on vascular dementia gets that much harder. 

The FDA seems to be willing to experiment by approving even somewhat dubious drugs, if the drug is targetting diseases for which there is no treatment at all.  Biogen's approval would take away one of the key crutches (dementia) on which Apabetalone could be approved quickly...if the FDA is so inclined.  I acknowledge that there is a difference between Alzheimer and vascular dementia, so maybe we still have a path to fix an untreated disease.

Also, it is one thing for a huge company like Biogen to make their case...something else for our US$250 million market cap company to be heard by the powers that be, at the FDA.