A non-inferiority trial is used to test whether an antibiotic is not inferior to an existing product. Non-inferiority is confirmed if efficacy is shown to be no less than a pre-specified value, the non-inferiority margin. Determining an appropriate non-inferiority margin is challenging, and regulators have provided detailed guidance on how it should be calculated.
Guideline on the choice of the non-inferiority margin (Committee for medicinal product for human use (CHMP), EMA, 2005)
Non-Inferiority Clinical Trials (FDA, 2018)
Defining the noninferiority margin and analysing noninferiority: An overview (British Journal of Clinical Pharmacology, 2017)
Through the looking glass: understanding non-inferiority (Trial, 2011)
REVIVE webinar: ‘Antibacterial drugs: Clinical development for non-developers Part 1: Traditional development – tiers A and B’ by David Shlaes (GARDP, 2018)