Biotech Values

[iwfal]

ONTY -

I will safely wager you the futility HR boundary will not be 1.0.

FYI I did the math and if they were using 20% as the Futility Threshold then the HR boundary at the interim of this thread would be 1.03.

Obviously at this latest interim the same futility limit give a value around 0.92.

Finally - for those who follow ONTY if a Futility Threshold of 50% is used the HR at this last interim has to be about 0.885 or better. But obviously it is heavily dependent on the Futility Threshold picked (20-50% being a good range of the possibilities of what Merck might have picked).

PS Obviously I created a tool to make this calculation less onerous.

Background: Futility limits at interims are done in an inherently odd and confusing fashion. The question asked is: "Given the HR seen at this interim, and assuming that for all the remaining events the nominal HR is the HR originally assumed in calculating the power of the trial before the first patient was enrolled THEN if the power of the trial to be stat sig now is less than x% then halt for futility.". Typical values for x range from 20% to 50 or 60%. As far as I can tell there is little consensus about which x should be used.