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RegisterDifferent power of AUC vs. Cmax at stage I - continuation rules [Two-Stage / GS Designs]
Hi Nisha,
good to hear the 2-stage approaches have not drawn their last breath.
Typically you do not need to make a distinction between AUCt and Cmax. You can go by the maximum observed CV - at the end of the day this can be argued to be both the most ethical and most scientifically relevant metric for the purpose of deciding if a stage II is needed and what the sample size should be.
In the (vast) majority of your studies you will see that CV for Cmax is higher than CV for AUCt; therefore it is generally also ok to write in the protocol that Potvin C is followed on basis of the Cmax data.
You would still be analysing AUCt and Cmax at stage II if one such is conducted, even if AUCt has been shown BE at stage I. And don't worry too heavily about the latter; if AUCt was ok at stage I then in all likelihood it will be as well at stage II.
Good luck.
good to hear the 2-stage approaches have not drawn their last breath.
❝ If, hypothetically, our results at stage I would have had good ratio, and failed to meet 94.12% CI BE criteria at stage I for both Cmax and AUC.
❝ The power analysis would have shown results higher than 80% for AUC, and lower than 80% for Cmax. Based on Cmax, we could continue to stage II.
Typically you do not need to make a distinction between AUCt and Cmax. You can go by the maximum observed CV - at the end of the day this can be argued to be both the most ethical and most scientifically relevant metric for the purpose of deciding if a stage II is needed and what the sample size should be.
In the (vast) majority of your studies you will see that CV for Cmax is higher than CV for AUCt; therefore it is generally also ok to write in the protocol that Potvin C is followed on basis of the Cmax data.
You would still be analysing AUCt and Cmax at stage II if one such is conducted, even if AUCt has been shown BE at stage I. And don't worry too heavily about the latter; if AUCt was ok at stage I then in all likelihood it will be as well at stage II.
Good luck.
—
Pass or fail!
ElMaestro
Pass or fail!
ElMaestro
Complete thread:
- Different power of AUC vs. Cmax at stage I - continuation rules Nisha 2015-09-17 13:28
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- Different power of AUC vs. Cmax at stage I - continuation rulesElMaestro 2015-09-17 13:56
- Different power of AUC vs. Cmax at stage I - continuation rules Nisha 2015-09-17 20:27
- AUC vs. Cmax ElMaestro 2015-09-17 21:53
- Assumption Helmut 2015-09-18 00:15
- Different power of AUC vs. Cmax at stage I - continuation rules Nisha 2015-09-17 20:27
- Different power of AUC vs. Cmax at stage I - continuation rulesElMaestro 2015-09-17 13:56
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