How to establish equivalence between treatments: A one-sided clinical trial in paediatric oncology

The design of a clinical trial to establish the equivalence of two treatments differs from that of an efficacy trial. The conventional null hypothesis of equivalent treatment efficacy is replaced by a null hypothesis of inequivalence which must be tested by appropriate statistics. In addition, the maximum allowable value of the true difference between the efficacy of two equivalent treatments must be specified. In oncology, such a trial is necessary when a standard treatment is replaced by a new less toxic one of equivalent efficacy. The statistical formulation is one‐sided. A trial comparing two pre‐operative treatments in childhood nephroblastoma is presented here and analysed according to this methodology.