Two-Stage Design for FDC [Two-Stage / GS Designs]

posted by Astea – Russia, 2019-06-06 01:24 (482 d 18:59 ago) – Posting: # 20319
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Dear Smart People!

I'm wondering what is an appropriate way to use Two-Stage Designs for FDC (two analytes, A and B, for example)? It seems we are facing several questions:
1). Initial sample size calculation - best guess of CV for two CV?
2). Initial sample size calculation - power (see this thread). So if we would not expect independent hypothesis we should use the adjusted power for calculation. Correspondingly this will lead to neccesity of using additional simulations cause we will be automatically driven from validated values of 80 and 90%.
3). Interim analyses: for 2 analytes it leads to different possibilities: pass, fail, pass for A but need the second stage for B...
4). Sample size for the next stage:
- additional subjects could cause TIE inflation (as in the example with extra drop-outs, see this thread
- is it regulatory addopted - ignoring data for the second analyte?

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