BETHESDA, MD 06 March 2009—FDA is seeking comments on proposed recommendations for the content of the clinical pharmacology section of labeling for drugs and biological products.
In a draft guidance document (PDF) for the industry, FDA explained that the agency wants to foster better communication of pharmacology information and ensure that the labeling information is consistent among prescription products.
In general, the document states, the clinical pharmacology section must contain information about how the drug acts in humans, although data from animal or in vitro studies may sometimes be appropriate. This portion of the labeling should include both positive and negative findings that are clinically relevant, and the language should be presented in a way that is understandable to practitioners who are not experts in clinical pharmacology.
The document asks manufacturers to use cross-referencing in other sections of the labeling that refer to topics covered under the clinical pharmacology section instead of repeating large sections of text throughout the labeling.
Within the clinical pharmacology section are three subsections. The mechanism of action subsection is for describing how the drug produces therapeutic and adverse effects, according to FDA. This area should also describe "relevant pharmacogenomic factors affecting drug action," the document states.
Dose-response information and all well-established pharmacologic effects should be described in the pharmacodynamics subsection. Also appropriate for discussion in this subsection is the drug or biological product`s effect on biological processes, such as the effect of an antihypertensive on angiotensin II activity if the drug acts via the renin-angiotensin system.
The guidance document includes a bulleted list about two pages long with details about specific information on the drug and its metabolites that should be described in the pharmacodynamics subsection.
An even longer list is provided for the third subsection, pharmacokinetics. In general, FDA wants this subsection to describe information for prescribers about the drug`s availability when delivered systemically and by other routes.
This subsection should also address variability in absorption and clearance among different patient populations but should begin with a presentation of information on which clinicians would base treatment decisions.
Certain recommendations would not be applicable to all products and "should be adapted to specific drugs and their conditions of use," according to the document.
For example, it will sometimes be appropriate to create a "pharmacogenomics" subsection to explain clinically relevant information about polymorphic variants that affect drug-metabolizing enzymes, transporters, or receptors. This subsection would contain information that is more extensive than would typically be found in the pharmacodynamics or pharmacokinetics subsections of the labeling.
Labeling for antimicrobial drugs should include a subsection on microbiology that describes the mechanism of action against the pathogen and, if appropriate, pharmacodynamic data on blood levels that affect resistance.
Comments on the draft document are due to the agency by June 1, according to a March 3 notice in the Federal Register.
