Two-stage design & RSABE: Forget it! [Design Issues]

posted by Helmut Homepage – Vienna, Austria, 2021-05-19 20:40 (32 d 12:52 ago) – Posting: # 22357
Views: 290

Hi Achievwin,

» 1) is there a precedence of conducting two stage study for 4-period full replicate design? (four periods in stage 1 and stage 2)

I have seen one since 2010. Not for RSABE but for the EMA’s ABEL. Asymmetric alphas – don’t remember which approach: Haybittle-Peto (0.001/0.049) or O’Brien/Fleming (0.005/0.048). Even in a 2×2×2 crossover TSD there is an inflated Type I Error. This study ended in a – vested – deficiency letter of the MHRA.

“The applicant has to demonstrate that the patient’s risk is controlled.”


» 2) what kind of penalty we can factor in?

That’s not the point and should be the least of your worries. Unless you have a magic wand providing you with a suitable adjusted α, no way.
Did you bother to read that (already linked in my previous post)?

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Helmut Schütz

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