This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Non-inferiority and superiority trials

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Non-Inferiority and Superiority Trials

The objective of non-inferiority trials is to compare a novel treatment to an active treatment with a view of demonstrating that it is not clinically worse with regards to a specified endpoint. It is assumed that the comparator treatment has been established to have a significant clinical effect (against placebo).

These trials are frequently used in situations where use of a superiority trial against a placebo control may be considered unethical.

Non-inferiority is most easily assessed using a confidence interval (CI) approach.

Firstly the trial investigators specify a non-inferiority margin, delta. This is the maximum difference that they are prepared to tolerate in a given direction if the new treatment is not to be considered (clinically) inferior.

If a 95% confidence interval for the difference between treatment means lies above or below this boundary value (in a favourable direction) then non-inferiority is deemed to have been established.

Logic of Non-Inferiority studies

  • If a standard S is consistently superior to placebo, then
  • to show that a test treatment T is superior to placebo
    • it suffices to show that the test treatment is as good as (not inferior) to the standard

Setting the non-inferiority margin

  • subjective - often contentious
  • if too large:
    • inferior treatments may be called non-inferior
    • if too small: huge sample sizes are required
  • usually a fraction of the historical difference between control and placebo

Interpreting a noninferiority trial as a superiority trial

Reference:


Related pages

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.

The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions.

Connect

Copyright 2024 Oxbridge Solutions Limited, a subsidiary of OmniaMed Communications Limited. All rights reserved. Any distribution or duplication of the information contained herein is strictly prohibited. Oxbridge Solutions receives funding from advertising but maintains editorial independence.