"why considerably more time than originally expected"?
If I was the potential partner I might want to wait for some more complete data from the trial (aprox. what would be submitted to the FDA). Even if GTCB gave the partner the raw data it might take them a few months to go through it.
Of course, even if this WAG is correct you still have to explain why GTCB was not aware of the partner's position.
I guess the worst scenerio is that there is an undisclosed issue in the data. But if so, why bother with a $6mm finance?