Bioequivalence and Bioavailability Forum

Dear All;

I recently performed an interim analysis of a two-stage study with Potvin Method C and here are the initial results (power evaluated with alpha level of 0.05)

LN AUCT: 77.81 - 96.71 Power: 91.55%
LN CMAX: 77.24 - 100.97 Power: 73.51

Given below the flowchart of Potvin method C, I believe this is a fail case where second stage is not required since power of only end-point is below 80%

Do you think is this the right way interpreting the results ?

Any help will be appreciated.


Thanks

C. Evaluate the power at stage 1 using the variance estimate from stage 1 and an a level of 0.05. If the power is greater than or equal to 80%, evaluate BE at stage 1 using an a level of 0.05 and stop whether BE is met or not. If the power is less than 80%, evaluate BE using an a of 0.0294. If the BE criterion is met, stop. If the BE criterion is not met, calculate the sample size based on the variance estimated at stage 1 and an a level of 0.0294 and continue to stage 2. Evaluate BE at stage 2 using data from both stages and an a level of 0.0294. Stop here whether BE is met or not and regardless of the power achieved.