Bioequivalence and Bioavailability Forum

Helmut, thank you very much for the reply related to the adjustment of alpha, testing of fed vs. fasted, as well as the detailed sample size discussion with R code provided.

Can you please also provide feedback on one more scenario:
6-way crossover, with the following treatments A) tablet formulation #1 fasted, B) tablet formulation #2 fasted, C) capsule formulation fasted, D) tablet formulation #1 fed, E) tablet formulation #2 fed, F) capsule formulation fed.

Is there an approach that can be used to test only the first 3 treatments (all fasted) in an interim fashion, and contingent upon the results continue to test the final 3 treatments (all fed)? We are assuming a typical Latin Square such as:

A B C D E F
B C D E F A
C D E F A B
D E F A B C
E F A B C D
F A B C D E

To allow the proposed interim analysis (all fasted), is it possible to execute only the first necessary part of the Latin Square, such as:

A B C x x x
B C x x x A
C x x x A B
x x x A B C
x x A B C x
x A B C x x

With completion of the remaining parts (all fed) after the interim analysis:

x x x D E F
x x D E F x
x D E F x x
D E F x x x
x x A B C x
F x x x D E

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Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post #5! [Ohlbe]