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 agree with mcbio because I would suggest that the market often ascribes significantly too much value to early products with unproven, or even mildly disproven, management. This is a corollary of a more general version of the Feurstein Ratain rule (the rule, as they strictly wrote it, applies only to onc companies - but I think a more general version to cover all biotech).