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Interpreting the results of noninferiority trials—a review

Research output: Contribution to journalReview articlepeer-review

Jack Cuzick, Peter Sasieni

Original languageEnglish
Pages (from-to)1755-1759
Number of pages5
JournalBritish journal of cancer
Issue number10
Early online date15 Sep 2022
Accepted/In press27 Jul 2022
E-pub ahead of print15 Sep 2022
Published9 Nov 2022

Bibliographical note

Publisher Copyright: © 2022, The Author(s).

King's Authors


Noninferiority trials are becoming increasing common, but are often poorly reported and misunderstood. A better understanding of the new components of a noninferiority trial and their interpretation is needed. Noninferiority trials are an extension of conventional superiority trials, which provide a basis for determining if a new treatment, which may have advantages other than efficacy, has sufficient efficacy to be useful in certain situations. A key feature is the need to specify a clinical noninferiority margin above which the lower boundary of the confidence interval for the difference between the new treatment and the conventional treatment must lie. In most cases a nontreated control arm is not included, and when the efficacy of the new treatment is less than that of the standard treatment, determining its efficacy versus no treatment can be a major challenge. Treatments meeting a clinical noninferiority requirement can be statistically significantly superior to standard treatment, of similar efficacy (i.e., no significant difference), or even significantly inferior in a conventional analysis. Noninferiority comparisons are an important addition to the reporting of clinical trials, but require prior consideration of several factors that conventional superiority analyses do not address.

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