Therapeutic equivalence: all studies are not created equal.

With an increasing number of available treatment options, clinicians must frequently evaluate whether comparable therapies are equivalent in terms of efficacy and safety. Two methodologically distinct study designs are used to establish therapeutic equivalence: standard superiority trials and true equivalence trials. In either study design, clinician-readers assess equivalence by examining both the statistical significance and the clinical importance of the study results (as defined by the minimally important difference, the smallest difference in patient outcome that would lead to an important difference in patient health status). Once therapeutic equivalence has been established, clinicians may select one therapy as the preferred treatment option because it offers other clinical benefits, such as a lower cost or a more convenient drug administration schedule.