I was speaking with a PharmD and hopefully you can
Post# of 148152
From what he was saying, typically the Halt for Efficacy at Interim Analysis for 50% enrollment will be equal to that of the penalty for unblinding, if required to go to completion.
Ex:
Halt at Interim= p<0.005
Penalty for Unblinding= p=0.005
Completion of Trial (post penalty): p<0.045
*Assuming the p value boundary is consistent with this, and we need p<0.005 to get halted, what kind of mortality numbers are we needing LL/control (130/65)