I really don't see how the existence of not of a secondary project should impact the decision about whether to play a binary Phase III or not. Both the up-move and the down-move will be smaller if some value is ascribed to the remaining pipeline - but you can adjust for that by increasing or decreasing your bet.
I didn't personally follow this drug, but on the surface it looked something on the order of a 50:50 shot given a decent inferiority margin. So I can certainly see how these name-brand investors had a position.