title: Monotherapy comparative trials: equivalence and differences in clinical trials.
abstract: Investigators are familiar with the concept of clinical trial design to detect differences. Equivalence studies set out to define how similar treatments might be. They become important for two reasons: (1) similarities may be as clinically important as differences and (2) in therapeutic areas with drugs of proven efficacy already marketed, it may be ethically difficult to perform placebo-control studies. If equivalence is rigorously defined (the minimal clinically important difference), they could represent a route to licensing (cancer chemotherapy and antibiotics). Equivalence will be defined by the limits of 95% confidence intervals for a comparison being constrained within pre-defined limits. As such, studies need larger numbers of subjects rather than difference studies, and intention-to-treat analysis may no longer be the more conservative approach.
authors.affiliation: University of Liverpool & Walton Centre for Neurology & Neurosurgery, Lower Lane, L9 7LJ, Liverpool, UK. d.w.chadwick@liv.ac.uk
authors.forename: D
authors.initials: D
authors.lastname: Chadwick
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D004827:Epilepsy / Q000188:drug therapy*; D006801:Humans; D012107:Research Design
chemical_list: D000927:Anticonvulsants