Very few P3 trials are stopped for either futility or the P value meeting some predefined threahold like .001
Then why did The Harv say (several times I might add), that based on the way the "trial is powered, there is a reasonable chance" it would be stopped at the 2nd Interim which would allow for an NDA filing. Merck clearly thought the same way if you listened to their conference call over the summer. So, despite you having said very few trials are stopped, both Merck and Ariad felt there was a "reasonable chance" it would be stopped. Why?
Just because a trial is stat sig at an interim does not get it stopped
Why were the Phase 3 trials in everolimus and temsirolimus stopped then, at the interim?