Equivalence Trial
A clinical trial designed to show that two treatments produce essentially the same effect, within pre-defined bounds. Equivalence designs are commonly used for biosimilar approval, where the goal is to demonstrate that the biosimilar performs comparably to the reference product.
Technical Context
Equivalence designs use two-sided testing: the 95% CI of the treatment difference must fall entirely within the pre-specified equivalence margins (-delta to +delta). This is more stringent than non-inferiority (which only tests one direction). Equivalence trials are used for: biosimilar comparisons (demonstrating the biosimilar is neither better nor worse than the reference product), bioequivalence studies (comparing PK parameters of generic vs brand formulations), and head-to-head comparisons where the goal is to demonstrate comparable efficacy. For peptide biosimilars, clinical equivalence trials typically use the same primary endpoint as the reference product's pivotal trial, with margins determined by reference to historical treatment differences.