The IR department of Merrimack may sound very upbeat, but it is true that that does not tell us the story. What were Merrimack's expectations vis-a-vis the FDA when they proposed the new trials? We don't know.
What we do know is that the data were very positive on safety, otherwise the FDA would never allow the new, much higher dosing, which is being used in the extra trials.
What we do not know is, to what extent we may expect significantly higher efficacy at those higher doses. The open question is whether Merrimack can say anything of substance right now, i.e. before the results of those new trials are known. If they (and GTCB) can, that would be extremely positive.