Equivalence trials can be used when the objective is to demonstrate
equivalence between two treatments or interventions or non-inferiority
of the new intervention to the existing one. Typically, the new
drug or device is expected
to match the efficacy of the current one but has advantages with regard
to
say, costs or side effects. The conduct of an equivalence trial
requires different techniques during the design and analysis compared
to the standard superiority trials described in the Trial Protocol Tool. In particular, standard sample size calculations are not
appropriate and an equivalence
trial requires more patients than a standard randomised controlled
trial.
See Further reading for more details.
Jones B, Jarvis P, Lewis JA, Ebbut AF. Trials to assess equivalence: the importance of rigorous methods. BMJ 1996; 313: 36-9.