Thanks CT.

The FDA guidance on adaptive trials clearly anticipates the situation where CYDY could have pre-defined p values for an interim analysis on any number of patients. The DSMC could have leeway to perform an interim analysis anytime they please, certainly a pre-planned 75% interim analysis would be no surprise.

I wonder if the 42 day mortality was anticipated as a possible adaptive endpoint then the DSMC could perform an interim analysis for the purpose of efficacy stop on that endpoint?

Is it possible that the efficacy stop endpoint p value may have already been met for the modified 42 day mortality primary endpoint, but they just can't stop the trial at the first interim analysis upon the modified primary endpoint?

If an anticipated adaptive primary endpoint exists, it probably cannot be claimed upon its initial observation. Probably you have to conduct an interim analysis, recommend the change in primary endpoint, and then conduct a second interim analysis.

I think Gilead's remdesivir was efficacy stopped at an interim analysis.

Maybe they were able to modify the remdesivir endpoint upon the first interim analysis? I don't know.