Assessment of Dose Proportionality: Report from the Statisticians in the Pharmaceutical Industry/Pharmacokinetics UK Joint Working Party

There are a number of different approaches to the assessment of dose proportionality, but most of these are directed toward hypothesis testing. The analysis of dose proportionality studies, however, requires estimation rather than significance testing in order that the pharmacokinetic and clinical significance of any nonproportionality can be assessed.The methods of statistical analysis of these studies have been reviewed. An empirical model relating the log of the pharmacokinetic parameter linearly to the log of the dose (the “power model”) provides a readily interpreted measure of the degree of nonproportionality. The potential utility of this model has been demonstrated using a number of observed dataseis from different drugs. If there is doubt over the goodness of fit of the power model then analysis of variance (after log transformation), together with pairwise comparisons between doses, provides a suitable alternative approach.