Trials to Show Equivalence or Non-inferiority are divided into two major objective-based categories. What are these two categories?

• A. Trials to Show Superiority
• B. Trials to Show Dose-response Relationship
• C. Equivalence trials and Non-inferiority trials
• D. Placebo-controlled Superiority Studies

Answer: (C)

Equivalence trials and non-inferiority trials.

In equivalence trials, the goal is to show the new treatment's effect lies within a pre-specified range around the reference—it's considered neither clinically better nor worse within that margin. Practically, you look for the entire estimated difference to fall within both positive and negative margins, often using a two-sided test or the two-one-sided tests approach.

In non-inferiority trials, the aim is to demonstrate the new treatment is not unacceptably worse than the standard by a defined non-inferiority margin. If the upper bound (or relevant confidence limit) of the difference is within that margin, non-inferiority is established.

Both require justified margins, adequate power, and careful trial design to ensure assay sensitivity; they are distinct from superiority trials, which seek evidence of clear benefit.