Q&A ref [Two-Stage / GS Designs]

posted by Astea – Russia, 2019-09-16 16:28  – Posting: # 20599
Views: 3,751

Dear Helmut!

» I was wrong and we shouldn’t worry. See Detlew’s simulations.

That's good. Sorry, I didn't realized it at first.

» How likely is it that AUC (which passed already in the first stage) will fail in the second?

Thank you for the example! I've puzzled whether it will be reproduced for other cases. Let us consider the situation when CV of Cmax and AUC are very close to each other, like 21% and 20%, and for the first stage the number of subjects (n1=20) was sufficient for AUC, but not for Cmax.
Calculation shows that even then the power for AUC for the second stage would be always enough.

for(j in 5:100){nj1<-sampleN.TOST(CV=j/100,print=FALSE)[1,7]
n02<-sampleN2.TOST(CV=(j+1)/100,n1=nj1)[1,8]
nj2<-nj1+n02
print(suppressMessages(power.TOST(CV=j/100,n=nj2-1,alpha=0.0294)))}


» Take some Schützomycin?

Did you patent that? I gonna make a generic :-D

» According to the Q&A:

stage, sequence, sequence × stage, subject(sequence × stage), period(stage), treatment.


Are there any documents to refer which mention this model (excepting the answer on the EMA's web page?)

» Ask Detlew or inspect the sources of power.tsd() and power.tsd.2m(). :-D

Ok, need more tea to dive to the source...

"Being in minority, even a minority of one, did not make you mad"

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