Rules/misleading presentation/US-MIS-014

No Erroneous Use of "No Significant Difference" to Claim Equivalence

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Rule

In a prescription drug advertisement, a statistical finding of "no significant difference" may not be used erroneously to claim clinical equivalence, or to deny or conceal the potential existence of a real clinical difference. This applies specifically to prescription drug advertising as defined under 21 CFR 202.1; it does not prohibit merely reporting a "no significant difference" result, only its erroneous misuse.

Check

In prescription drug promotional/advertising material, if "no significant difference" language is used, verify it is not being converted into an equivalence claim or used to obscure a potential real clinical difference. A violation occurs when the material states or implies "no significant difference" therefore means the drugs are clinically equivalent, or uses the null finding to mask evidence suggesting a real clinical difference may exist.

Escalate when

Escalate when it is unclear from a statistical standpoint whether the "no significant difference" finding is being erroneously extended into an equivalence claim (versus accurately reported as a null result), or whether contrary evidence of a real clinical difference is being concealed — these determinations require statistical/clinical judgment.

Where this comes from

21 CFR 202.1(e)(6)(xv). The highlighted words are quoted exactly; a script confirms they appear in the source before the rule can be published.

… is intended for use on normal individuals. (xiv) Uses “statistics” on numbers of patients, or counts of favorable results or side effects, derived from pooling data from various insignificant or dissimilar studies in a way that suggests either that such “statistics” are valid if they are not or that they are derived from large or significant studies supporting favorable conclusions when such is not the case. (xv) Uses erroneously a statistical finding of “no significant difference” to claim clinical equivalence or to deny or conceal the potential existence of a real clinical difference. (xvi) Uses statements or representations that a drug differs from or does not contain a named drug or category of drugs, or that it has a greater potency per unit of weight, in a way that suggests falsely or misleadingly or without substantial evidence or substantial clinical experience that the advertised drug is safer or more effective than such other drug or drugs. (xvii) Uses data favorable to a drug derived f…

Open the original at these words on ecfr.gov ↗Read our full copy →

Document: 21 CFR 202.1
Version: 2026-09-16 — the link above is pinned to this date, so it shows the text as it stood then
Retrieved: 2026-09-21 from www.ecfr.gov
Fingerprint: a542640a872b3f2702d549e8…

Applies when

Naturepromotional

Productdrug

How this rule was checked

Citation proven by script and passed an independent verifier running on a different model. Not yet confirmed by a human.

Drafted
claude-sonnet-5 · 2026-09-21
Independent verification — revise
claude-opus-5 · 2026-09-21
Reviewer's reasons
- Supported: the quote is verbatim operative text from 21 CFR 202.1(e)(6)(xv), sitting under the mandatory chapeau 'An advertisement for a prescription drug is false, lacking in fair balance, or otherwise misleading ... if it', so a flat prohibition is the correct reading. It is not drawn from an example, definition, or preamble.
- Correctly sourced from (e)(6) ('is false ... misleading') rather than the adjacent permissive (e)(7) list ('may be false ... misleading'), so the obligatory phrasing of the rule statement is not an upgrade of hedged language.
- authority 'binding' is correct: this is a codified FDA regulation, and violation is tied to misbranding under section 502(n) of the act.
- determinism 'judgment' is correct: the provision turns on the word 'erroneously' and on whether a null finding has been over-extended into an equivalence claim, which is an inferential/statistical assessment, not presence/absence or literal match.
- severity 'blocker' is defensible: items in (e)(6) are per-se findings of a false or misleading advertisement and render the drug misbranded.
- Atomic: the two limbs (claiming clinical equivalence; denying or concealing a potential real clinical difference) are alternative consequences of one predicate misuse of a single statistical finding, checked in one pass; not independently checkable requirements.
- Locator 21 CFR 202.1(e)(6)(xv) is exact and matches the quoted subparagraph.
- Overstated on scope: the operative sentence of (e)(6) is expressly limited to 'an advertisement for a prescription drug', and 202.1 governs prescription drug advertising. The rule's applies_when fires on all promotional material with no such limit, extending the provision to media and product categories this citation does not reach.
- The source also provides an express FDA waiver mechanism for 'any provision of this paragraph', confirming the provision is a bounded prescription-drug advertising rule rather than a universal promotional prohibition.
Revised by the drafter
claude-sonnet-5 · 2026-09-21
Independent verification — pass
claude-opus-5 · 2026-09-21
Reviewer's reasons
- The quote is verbatim item (xv) in the enumerated list under (e)(6), 'Advertisements that are false, lacking in fair balance, or otherwise misleading' — a list of conduct that renders a prescription drug advertisement violative of section 502(n). It is an operative prohibition, not an example, definition, or description of what is not required, so the rule statement follows directly from the source.
- Locator is accurate: the quoted sentence appears in the source as subparagraph (xv) of paragraph (e)(6) of 21 CFR 202.1.
- Not overstated. The source frames (e)(6) conduct as per se violative ('is false ... if it'), in contrast to the weaker (e)(7) list ('may be false ... if it'), so stating the conduct as impermissible rather than merely risky is faithful. The rule also correctly preserves the word 'erroneously' by expressly noting that accurate reporting of a null result is not prohibited — that limitation is a fair reading of the source's qualifier and avoids overreach.
- Atomic. Although the source names two manifestations (claiming clinical equivalence; denying/concealing a potential real clinical difference), both are triggered by the same predicate — erroneous use of a 'no significant difference' finding — and constitute one prohibited practice rather than independently checkable obligations.
- Determinism 'judgment' is correct: whether use of a null finding is 'erroneous' or whether contrary evidence is being concealed turns on statistical and clinical interpretation, not on presence/absence of a literal string. The escalation trigger is aligned with that.
- Authority 'binding' is correct — 21 CFR 202.1 is a codified regulation, and this is a substantive provision within it.
- Severity 'blocker' is defensible: the conduct falls in the (e)(6) per se list, dissemination of which renders the advertisement misbranding-triggering under section 502(n).
- applies_when is justified and not invented: the source provision is expressly limited to advertisements for prescription drugs, and the rule statement carries that limit ('In a prescription drug advertisement'; 'applies specifically to prescription drug advertising as defined under 21 CFR 202.1'). Minor note only: the Check's phrase 'promotional/advertising material' is slightly looser than the source's 'advertisement' (promotional labeling is governed elsewhere), but the prescription-drug qualifier is retained and the drafted rule text states the limit explicitly, so this is a wording preference rather than a substantive defect.
- Noted but not disqualifying: the source contains a proviso allowing FDA to waive any provision of paragraph (e) for a specified advertisement on petition. This is an FDA-granted exception that does not change the default compliance posture a reviewer applies.