As likely is that ALKS took the bone on what it had already determined was not worth going alone.
In comparison to research budgets, neither company is concerned if it proves to be another rabbit hole through which to reach Wonderland.
AVXL literally has nothing to lose. Those within the Company have already made significant returns on granted stock and salary. "Retail" has proven to be "forgivingly optimistic" allowing continued shelf offerings.
Perhaps the science has been resolved negatively to the satisfaction of a Larger Bio (or two, three, etc).
The gamble continues to be: Who is correct? My wager remains minor.