Abstract
For decades, the superiority trial has been the most popular design to assess the
efficacy of newly developed drugs in a randomized controlled clinical trial. In a
superiority trial, the aim is to show that the new (experimental) treatment is better
than the standard treatment or placebo. However, it becomes increasingly difficult
to improve the efficacy upon that of existing drugs. For this reason, noninferiority
designs have been suggested. In a noninferiority study, one aims to show that the
experimental treatment does not lower the efficacy of the standard treatment too much,
but this loss of efficacy should be compensated by other better properties. In this
article, the design, aims, and properties of the superiority and the noninferiority
trial are contrasted and illustrated on recently published studies to treat patients
with advanced hepatocellular carcinoma. The author discusses the reasons why noninferiority
studies are becoming popular, but also why the results of noninferiority studies may
be difficult to interpret and can be easily misused. Since only a few noninferiority
studies in hepatocellular cancer have been organized, also examples from other therapeutic
areas were taken. Finally, it is indicated how to appreciate the qualities of published
noninferiority studies.
Keywords
equivalence trial - noninferiority trial - nonsignificance - superiority trial
