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Non Inferiority Trial. event rate. 0%. 100%. superiority study. control - placebo. experiment - drug . experiment better. experiment worse. -∞. +∞. 0. ARR=EER-CER. CER. EER. 0%. 100%. event rate. superiority study. control - placebo. experiment - drug .
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event rate 0% 100% superiority study control - placebo experiment - drug
experiment better experiment worse -∞ +∞ 0 ARR=EER-CER CER EER 0% 100% event rate superiority study control - placebo experiment - drug
presumption that experiment may be worse than control! But does it matter? is it clinically significant? 0% 100% non inferiority study control - drug A experiment - drug B
a positive non inferiority trial result supports the statement that the experimental treatment is no worse than the standard treatment✱ ✱within a predetermined acceptable margin of equivalence
margin of equivalence“how much worse than the active control you’re willing to accept” ok if not worse than X% 0% 100% non inferiority study control - drug A experiment - drug B
non inferior inconclusive experiment better experiment worse +∞ -∞ X% 0 if upper CI is less than X, non inferior! 0% 100% non inferiority study control - drug A experiment - drug B
the margin of equivalence is determined by • what is deemed to be a clinically significant difference, • the expected event rates, • regulatory requirements, • the known effect of the standard treatment over placebo, • severity of the disease, • toxicity, • inconvenience, or cost of the standard treatment, adherence and • the primary endpoint.
Superiority Trial • type I error is falsely finding a treatment effect when there is none • type II error is failing to detect a treatment effect when truly one exists. Non inferiority Trial • the null and alternative hypotheses are reversed; • type I error is the erroneous acceptance of an inferior new treatment, • type II error is the erroneous ejection of a truly non inferior treatment
non inferior inconclusive experiment better experiment worse +∞ -∞ 7% 0 0% 3.3% 100% treatment failure at day 10 control - Abx experiment - No Abx
non inferior inconclusive experiment better experiment worse 1.2% 6.8% +∞ -∞ 7% 0 0% 4.1% 5.3% 100% treatment failure at day 10 control - Abx experiment - No Abx
non inferior inconclusive experiment better experiment worse 13.5% 24.3% +∞ -∞ 7% 0 0% 12.9% 26.4% 100% new lesions at day 10 control - Abx experiment - No Abx