What type of trial is designed to show that the investigational product is equivalent to, or not worse than, a reference treatment?

• A. Trials to Show Superiority
• B. Trials to Show Dose-response Relationship
• C. Trials to Show Equivalence
• D. Trials to Show Equivalence or Non-inferiority

Answer: (D)

The idea being tested is how trials compare a new treatment to a reference. The phrase “equivalent to, or not worse than” covers two designs: equivalence trials and non-inferiority trials. Equivalence trials aim to show the investigational product falls within a predefined acceptable range around the reference on both sides of zero difference, meaning it’s neither notably better nor notably worse. Non-inferiority trials aim to show it is not worse than the reference by more than a predefined margin, focusing on ruling out being meaningfully worse. Since the statement includes both equivalence and not worse (non-inferiority), the best answer is the design that encompasses either outcome. Superiority trials seek to prove the new product is better, which doesn’t fit the “equivalent or not worse” goal, and dose–response studies examine the relationship between dose and effect, not the comparative goal to a reference treatment.