What indicates the period effect and sequence effect in a typical 2-way crossover bioequivalence study with a proper washout period?
Bala: In 2×2 cross-over design, we don’t have enough information to separately estimate sequence effect, carry-over effect and treatment-by-period interaction effects (effects are confounded). Also, the test on treatment effect is a conditional test assuming no sequence effect. Therefore, if sequence effect is significant in this design, you may have to use only the data from first period to assess bioequivalence which may not have enough power. The significant period effect indicates that the study conditions might have changed from period to period and the analysis does adjust for this in estimating the treatment effects.
