First of per management there is no interim analysis schedules for efficacy
The definition for interim analysis for efficacy: To see if the new treatment is overwhemingly better than the control group. If Yes than stop trial pass go and collect tons of $$$$$$$$$$$$ on your stock holdings.
There are 2 interim analysis scheduled for utility.
definition: To see if thr new treatment is unlikely to beat the control group/arm. If yes than stop the trial
Per the SPA this utility analysis is going to be based on months of survival nothing more nothing less.
Box, Cormack has said a couple of times (most recently at the end of the Q&A during the Q4 CC) that there will be two futility and one interim efficacy analysis. He wouldn't say whether any of those analyses have already occurred and he said there would be no announcement unless the trial is stopped.
Summer has said that when she has time she'll explain how a futility analysis is done. I'm interested in that, as well as in getting her take on whether if SYNERGY passes both futility tests we should draw any encouragement regarding the efficacy or the final analysis. I hope she's able to find the time.