Clinical Equivalence—A Clarification

Abstract

Despite the increasing use of randomized clinical trials to investigate clinical equivalence between regimens, a misunderstanding concerning the design and analysis of such trials continues to exist. We, therefore, prepared this paper, hoping to clarify some fundamental issues concerning equivalence trials. We begin by reviewing the definition of clinical equivalence and discussing two common approaches to making decisions concerning clinical equivalence. We contrast the hypothesis testing approach to establish equivalence with that to show superiority. We argue that should the right kind of decision rules be used for equivalence determination, statements such as “equivalence trials promote sloppiness in trial design and conduct” can never be held against such trials. We conclude by giving some suggestions to help dispel common misconceptions about equivalence trials.