In superiority trials, which approach most convincingly demonstrates efficacy?

• A. Trials to Show Superiority are determined by comparing to historical controls
• B. Demonstrating superiority to placebo in a placebo-controlled trial
• C. Equivalence with non-inferiority objectives
• D. Dose-response relationship studies in animals

Answer: (B)

Demonstrating efficacy is strongest when the experimental treatment is shown to outperform a placebo in a randomized, placebo-controlled trial. This design directly isolates the treatment effect from placebo responses and other biases, providing clear evidence that the intervention yields a real benefit beyond no active treatment. Historical controls are unreliable because patient populations and care practices change over time, which can bias comparisons. Equivalence or non-inferiority frameworks aim to show the new treatment is not worse than an active comparator within a margin, not to prove it works better. Animal dose–response studies are preclinical and do not establish efficacy in humans.