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Can you determine superiority from a non-inferiority trial?
In a non-inferiority trial, the focus is on the lower bound margin, what happens at the upper end is not of primary concern in this type of trial design. One can also declare superiority in a non-inferiority trial if the lower limit of CI of the new treatment is above the non-inferiority margin and above zero.
What is a noninferiority margin?
By definition, a non-inferiority trial aims to demonstrate that the test product is not worse than the comparator by more than a small pre-specified amount. This amount is known as the non-inferiority margin, or delta.
How is non-inferiority margin decided?
In order to demonstrate non-inferiority, the recommended approach is to pre-specify a margin of non- inferiority in the protocol. After study completion, a two-sided 95% confidence interval (or one-sided 97.5% interval) for the true difference between the two agents will be constructed.
What should be the statistical power of a non inferiority trial?
Both superiority and non-inferiority trials should ideally be designed with a ≥90% statistical power. In non-inferiority trials this is more crucial, since lower power biases the results towards non-inferiority.
How to calculate the power of a noninferiority test?
You can use PROC POWER to analyze power and determine sample size for a variety of noninferiority tests. Power analyses for noninferiority tests can be performed on means for normal data, geometric means for lognormal data, or proportions for frequency data.
What are the risks of a non inferiority study?
Non-inferiority studies often have ‘substantial methodological flaws’ with the risk of incorrectly claiming non-inferiority. 3 This could potentially expose patients to the possibility of receiving a treatment that is inferior to the ‘gold standard’.
How to analyze data from a noninferiority trial?
Analysis of noninferiority trials A naïve approach to analyzing experimental data from active control trials is to compare new and control treatments in the standard way and, if no difference is detected, to declare the treatments equivalent.