Certified Clinical Research Associate (CCRA) Practice Exam

What is the primary objective of an Equivalence Trial?

1. To show a significant difference between treatments

2. To demonstrate that treatments differ by an unimportant amount

3. To compare the efficacy of two active treatments only

4. To establish the safety of a treatment over a longer period

The correct answer is: To demonstrate that treatments differ by an unimportant amount

The primary objective of an Equivalence Trial is to demonstrate that treatments differ by an unimportant amount. This type of clinical trial is designed to show that the effect of the new treatment is statistically similar to that of a standard treatment, within a predetermined margin of equivalence. The goal is not to prove that one treatment is superior to the other, but rather to establish that any difference in effects is small enough that it can be considered clinically insignificant. This is particularly relevant when evaluating new therapies that may be more convenient or less expensive than existing treatments but are expected to have a similar efficacy. In the context of the other options, showing a significant difference between treatments does not align with the purpose of an Equivalence Trial, as it seeks to establish similarity rather than difference. Comparing the efficacy of two active treatments only, while important, is narrower than the equivalence concept, which encompasses establishing that they do not differ significantly within the specified margin. Lastly, establishing safety over a longer period is more characteristic of safety trials or post-marketing studies than an Equivalence Trial, which focuses primarily on efficacy and the demonstration of similarity.