SP08
Bayesian Analysis of Population Bioequivalence Using the Independence Chain Algorithm in PROC MIXED
Richard J. McNally, Colorado State University

The statistical test for population bioequivalence given in the current FDA guidance document on this matter ignores the dependence between summary statistics. Therefore, it is extremely conservative in cases where there is a high degree of correlation of subject responses between test and reference formulations, which is usually the case in bioequivalence studies. Adapting the ideas of Kass and Wolfinger (Bcs2000), we use the PRIOR statement in PROC MIXED to approximate the posterior distribution of t he population bioequivalence parameter $\Theta_{PBE}$, from which we can construct tests based either on the probability of the upper tail region (ie, $Pr(\Theta_{PBE}>\Theta_0)$), or on the one-sided upper 95% confidence bound of $\Theta_{PBE}$,. We show that this test can conclude population bioequivalence when the FDA method does not. We also examine the statistical properties of this approach.