Biotech Values

[DewDiligence]

Addendum re BIOD and non-inferiority analyses:

>How common is that [for a trial to be statsig non-inferior as well as statsig inferior]?<

Following up on the comments in #msg-32024599: There’s a notable case where the combination of statsig non-inferior and statsig inferior is clearly impossible:

1. The finding of non-inferiority requires that the good-side bound on the 95% CI for the treatment difference be on the good side of zero. (This is sometimes, but not always, a requirement specified in a statistical-analysis plan for non-inferiority.)

2. There is a two-sided test for superiority/inferiority rather than a one-sided test for superiority per se.

3. The non-inferiority test and the superiority/inferiority test are conducted on the same endpoint using the same methodology.

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For a finding of inferiority, #2 above requires that the good-side bound on the 95% CI for the treatment difference be on the bad side of zero, and hence #2 is incompatible with #1. It follows that the treatment in question can’t be both statsig non-inferior and statsig inferior.