Chapter 1, Section 1(15) of the Guide states: "Do not include descriptions that could lead to disparagement or defamation of other companies or their products." Comparative trial data appear regularly in promotional materials for prescription drugs. Showing a difference from a control drug is a presentation of scientific fact — material that helps healthcare professionals make prescribing decisions. The problem arises when the author's interpretation or evaluation becomes mixed into that data. At that point the material shifts from scientific description toward either a disparagement of a competitor or a self-serving endorsement.
The core principle is separating the fact of comparison from a verdict of superiority or inferiority. Reporting the results of a comparative clinical trial belongs to scientific description. Evaluating the control drug as "inferior," or emphasizing that it was "insufficient," belongs to advertising manipulation. The former is permitted; the latter is not. Understood this way, the prohibition on disparagement is not about courtesy toward competitors — it is a firebreak against advertising logic eroding scientific description. The foreword's principle of "informing accurately without misleading" takes the form here of "do not mix evaluation into fact."
01Report the results; do not evaluate them
Detailed rule (a) states: "When recording the results of a control drug in a comparative clinical trial, do not include an evaluation or commentary on the results." Showing the control drug's numerical results in a material is in principle permitted. What may not be included is any interpretation of those numbers — phrases like "the control drug did not produce an adequate response" or "the investigational drug was significantly superior to the control."
The reason is this: the moment the author annotates the control drug's results, the material retains the appearance of scientific description while functionally becoming a tool for evaluating and criticizing a competitor's product. A numerical result extracted from a particular trial, combined with the author's "commentary," creates an impression in the reader's mind about what that drug is like. That amounts to circulating the author's own assessment of a competitor's product within a promotional material.
Detailed rule (b): emphasizing ineffectiveness, inadequacy, or intolerance
Detailed rule (b) states: "Do not include descriptions that emphasize that treatment with another company's product was ineffective, insufficient, or intolerable in a comparative clinical trial." The number of subjects in the control arm who showed no response, or the number who dropped out due to tolerability problems, may appear in the trial overview as part of the factual record. The issue is emphasis.
- Using bold type or color to highlight only the competitor's figures
- Using phrases such as "many cases were non-responders" or "the drug was not tolerable" in headings or callout boxes
- Using figures or arrows to visually underscore the poor results of the control drug
Such techniques lead the reader from the trial's facts toward the impression that "the control drug cannot be used." Read alongside rule (a) — "do not provide commentary" — the structure of the prohibition becomes clear: even listing numbers can constitute disparagement depending on how they are edited, and rule (b) blocks that. Rule (a) prohibits verbal evaluation; rule (b) prohibits visual and rhetorical manipulation through emphasis.
02Do not provide commentary on prior therapy
Detailed rule (c) states: "Do not provide commentary on prior therapy drugs (products of other companies)." Clinical trials sometimes include patients who switched from one drug to another. Eligibility criteria may specify "patients with an inadequate response to [another company's product]" or "patients who experienced adverse reactions to [another company's product]." These are facts of the trial design.
But going further — explaining what the prior therapy drug is, why it was inadequate, or what its adverse-reaction profile looks like — is not permitted in the material. Doing so embeds content that evaluates a competitor's product within a material that appears to be presenting data for one's own drug. This is precisely the pattern that rules (a) and (b) seek to prevent: an advertising manipulation dressed in the form of factual presentation.
If the identity and dosage of the prior therapy drug are necessary to understand the trial design, they may be recorded as a factual entry within the scope of detailed rule (d). Commentary, however, may not be added. Describing a trial's context and providing commentary on the prior therapy are different acts.
03Other companies' products by generic name; trial facts recorded accurately
Detailed rule (d) states: "In trial overviews, record the names of drugs used (other companies' products by generic name), the dosing period, the dose, the number of cases, and so on as accurately as possible." This rule sets both the scope of permissible information and the manner of recording it.
Why other companies' products are named generically
Other companies' products are referred to by generic name. This is not convention but a deliberate rule. Using a brand name would cause the material to distribute a competitor's trademark. It could also give a strong impression to a particular brand — either disparaging it or inadvertently promoting it. A generic name reduces a drug to its pharmacological identity, a form of reference that carries little evaluative weight. Using scientific vocabulary for competitor products is the technical device that keeps comparative "factual description" from sliding into advertising "evaluation."
When multiple products from the same company appear in a single trial, brand names for own-company products may also be given. The underlying principle is not "own company vs. other company" but rather "does it lead to evaluation or emphasis?"
The duty to record as accurately as possible
The phrase "as accurately as possible" imposes an affirmative obligation: vagueness about dosing period, dose, and case numbers is not permitted. The reason is that if these figures are omitted or imprecise, the reader cannot properly assess the quality of the trial or whether the comparison was made under equivalent conditions.
- Without the dose, it is impossible to judge whether the comparison was conducted on equal terms
- Without the case count, the precision of the effect estimate cannot be evaluated
- Without the dosing period, the interpretation of the observed outcomes may change
Accuracy is demanded so that readers can evaluate the trial on their own. This connects directly to one of the foreword's three pillars: verifiability. Since the author adds no evaluation, the reader must be left with enough accurate information to evaluate independently — that is the function of rule (d).
The prohibition on disparagement is not a provision that "protects" competitors. It is a provision of expressive discipline: do not conflate scientific factual description with advertising evaluation. The control drug's results may stand as fact. The moment evaluation, emphasis, or commentary is added, fact becomes a tool for criticizing another company's product. Referring to competitors by generic name and recording dosing conditions accurately are the specific technical measures that hold the line.
Detailed rules (a), (b), (c), and (d) form a sequence: "do not evaluate," "do not emphasize," "do not provide commentary" — but "do record the facts accurately." The prohibition does not only demand omission. It is paired with the affirmative duty to preserve, with precision, the facts that must be preserved. This is the foreword's two requirements — "inform accurately without misleading" and "guarantee verifiability through structure" — showing up concretely in the handling of comparative trial data.