title: Some remarks about the analysis of active control studies.
abstract: In an active-controlled trial, the experimental treatment can be declared to be non-inferior to the control if the confidence interval for the difference excludes a fixed pre-specified margin. Recently, some articles have discussed an alternative method where the data from the current study and placebo-controlled studies for the active control are combined together into a single test statistic to test whether a fixed fraction of the effect of the active control is preserved. It has been shown that, conditional on nuisance parameters from the active-controlled study, a fixed margin can be defined that will be operationally equivalent to this latter method. In this article, we will discuss statistical properties associated with these approaches. Specifically, the interim monitoring boundaries and level of evidence will be considered.
authors.affiliation: Division of Biometrics I, OB/CDER, Food and Drug Administration, HFD-710, 15B-45, 5600 Fishers Lane, Rockville, MD 20857, USA. lawrencej@cder.fda.gov
authors.forename: John
authors.initials: J
authors.lastname: Lawrence
mesh_terms: D018849:Controlled Clinical Trials as Topic / Q000379:methods* / Q000592:standards*; D006801:Humans; D015233:Models, Statistical; D004364:Pharmaceutical Preparations / Q000592:standards; D011237:Predictive Value of Tests
chemical_list: D004364:Pharmaceutical Preparations