Non-Inferiority Trial
A trial designed to demonstrate that a new intervention is not worse than an active comparator by more than a pre-specified, clinically acceptable margin.
Definition
A non-inferiority trial is designed to demonstrate that a new intervention is not unacceptably worse than an active comparator. The pre-specified non-inferiority margin (delta) defines the largest difference that would still be considered clinically acceptable; a one-sided 95% confidence interval that excludes a difference worse than the margin establishes non-inferiority. Common in MedTech when a placebo or sham control would be unethical (e.g., comparing a new drug-eluting stent against an established one).What this means in practice
Margin selection is the most contested element. FDA expects the margin to be both clinically defensible and to preserve a meaningful fraction of the comparator's effect over placebo (the 'M1/M2' framework).Examples
- A study comparing a novel, less invasive surgical technique for joint replacement against the standard open surgery, aiming to show it is not significantly worse in terms of patient recovery and long-term joint function.
- A clinical trial evaluating a new diagnostic imaging modality for detecting a specific disease, demonstrating that its accuracy is comparable to the currently accepted gold standard, without being unacceptably inferior.
- Research assessing a new, more user-friendly insulin delivery device against an established device, to confirm that its effectiveness in glycemic control is not worse by a clinically relevant amount, while offering other benefits.
- •Choosing a margin that's clinically defensible but doesn't preserve enough of the active comparator's effect, FDA will reject the design.
- •Running a non-inferiority trial with poor protocol adherence, drift biases toward the null and toward false NI conclusions.
Frequently asked questions
Related terms
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· Hand-selected related conceptsTrial design that pre-specifies opportunities to modify aspects (sample size, arms, endpoints) based on interim data.
Single endpoint combining multiple component outcomes (e.g., MACE = death + MI + stroke).
International standard for the design, conduct, and reporting of clinical trials.
Definitive clinical study designed to establish safety and effectiveness for marketing authorization.
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· Same categoryAny untoward medical occurrence in a subject, whether or not related to the device.
Data integrity principles: Attributable, Legible, Contemporaneous, Original, Accurate (plus Complete, Consistent, Enduring, Available).
An IVD's ability to detect small quantities of an analyte.
Trial design that uses Bayesian statistics, often incorporating prior data from related studies or registries.
Where this term appears across MedTech Terms.
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Sources
3 sourcesSources support the definition or relevant regulatory context, not necessarily every claim on this page. Each is graded against our source-tier hierarchy so you can see what rests on binding law versus commentary.
- 1FDA Guidance, Non-Inferiority Clinical Trials (2016)Tier 2 VerifiedFDAfda.gov
- 2ICH E10 Choice of Control GroupTier 2 VerifiedICHich.org
- 3ICH GuidelinesTier 2 VerifiedICHich.org
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