Edgar Diletti

Learn More
The statistical analysis of bioequivalence assessment has been consolidated in recent years through the work of Schuirmann [1987], Westlake [1988] and Hauschke et al. [1990], and this has been reflected in the CPMP Note for Guidance on Bioavailability and Bioequivalence and in the joint recommendations of the APV (International Association for(More)
Equivalence trials aim to demonstrate that two treatments do not differ by more than a prespecified clinically irrelevant amount. We consider the problem when equivalence is defined in terms of the ratio of population means and the original (untransformed) data are normally distributed. Application of the intersection-union principle to the test proposed by(More)
In bioequivalence assessment, the consumer risk of erroneously accepting bioequivalence is of primary concern. In order to control the consumer risk, the decision problem is formulated with bioinequivalence as hypothesis and bioequivalence as alternative. In the parametric approach, a split into two one-sided test problems and application of two-sample(More)
In bioequivalence studies C max and AUCserve as the primary pharmacokinetic characteristics of rate and extent of absorption. Based on pharmacokinetic relationships and on empirical evidence, the distribution of these characteristics corresponds to a multiplicative model, which implies a logarithmic normal distribution in the case of a parametric analysis.(More)
For the two-period crossover design and a multiplicative model (logarithmic normal distribution) the decision procedure of choice is based on the inclusion of the shortest 90%-confidence interval for the ratio of expected medians for test and reference in the equivalence range. This inclusion rule is equivalent to the two one-sided tests procedure. Sample(More)
BACKGROUND Roflumilast is an oral, selective phosphodiesterase (PDE)-4 inhibitor in development for the treatment of chronic obstructive pulmonary disease (COPD). Both roflumilast and its metabolite roflumilast N-oxide have anti-inflammatory properties that contribute to overall pharmacological activity. OBJECTIVES To model the pharmacokinetics of(More)
For a two-way cross-over design, which appears to be the most common experimental design in bioavailability studies, 95%-confidence limits for expected bioavailability can be obtained by classical analysis of variance (ANOVA). If symmetry of the confidence interval is desired about zero (differences) or unity (ratios) rather than about the corresponding(More)
Based on general guidelines and requirements for the design and analysis of bioequivalence studies, specific recommendations are made for the presentation of results, both in tabular and graphical form. This is done by means of two examples, one of a single-dose study and one of a multiple-dose study. The recommendations in this paper are twofold. Firstly,(More)
Bioequivalence studies are usually performed as crossover studies and, therefore, information on the intrasubject coefficient of variation is needed for sample size planning. However, this information is usually not accessible in publications on bioequivalence studies, and only the pooled inter- and intrasubject coefficient of variation for either test or(More)
An open question in the analysis of average bioequivalence is whether the nonparametric (Wilcoxon) or parametric (t) approaches to two one-sided tests is preferable. Previous work has made particular distributional assumptions as to the distribution of AUC and C(max). Instead, we simulate data according to a pharmacokinetic model for an immediate-release(More)