Bioequivalence and Bioavailability Forum

Dear Helmut,

❝ ... Borderline highly variable, both for C_max and AUC. Previous studies contradictory; CV reported with ~20–40%. Since for an European submission scaling AUC is not possible and the CV was unclear we considered various TSDs (“type 2”: T/R 0.95, target power 80% with optimized adjusted α for n₁ 16–66, CV 15–60%).

From that I assume that you aimed for an European submission.
But then I wonder: Type 2 aka Potvin C? No longer regulatory caveats expected for this?

❝ ... Our final design was (based on a “best guess” CV of 30%) a sample size of 46 and an FC of ]0.8250–1.2121[. We expect for this CV a power in the first stage of 80.3% and 61.3% for a CV of 35%. Chances to proceed to the second stage are 10.1% and 28.2%. Overall-power is expected with 85.3% and 83.2%. We will have still 80% power for a CV up to 46% (very unlikely, anyhow). In this extreme case the average total sample size will be 79. Let’s see.

Sorry, I can't reproduce your numbers. Could you please write down the power.2stage.fC() call?