Rockville, MD (May)—The US Food and Drug Administration (FDA, www.fda.gov) issued a draft guidance “Labeling for Human Prescription Drugs—Determining Established Pharmacologic Class for Use in the Highlights of Prescribing Information.”

The guidance is meant to help applicants and review staff in FDA’s Center for Drug Evaluation and Research “determine when a drug belongs to an established pharmacologic class” and “how to select the appropriate word or phrase that describes the pharmacologic class for inclusion in the Indications and Usage section of Highlights of Prescribing Information of approved labeling.”

According to a final rule published by FDA in January 2006, a drug that is a member of an established pharmacologic class must have the name of the class and the drug’s indications clearly labeled under the Indications and Usage section of Highlights. Pharmacologic class is defined on the basis of the drug’s mechanism of action (MOA), physiologic effect (PE), or chemical structure (CS).

According to the new draft, a single drug can have multiple scientifically valid pharmacologic classes. Only the pharmacologic classes that are clinically meaningful (that is, they enhance the ability of professionals to understand the therapeutic effects or undesirable effects of the drug) as well as scientifically valid can be the drug’s established pharmacologic class. The draft goes on to give several examples of how to determine the correct pharmacologic class for a drug and the circumstances in which a combination of established pharmacologic classes may be included on the drug’s label.

FDA goes on to state that new drugs undergoing review for marketing or licensing approval will have their proposed established pharmacologic class reviewed by FDA for scientific validity based on submitted evidence that supports the claim that the pharmacologic class is known and relevant to the indication under review. If an applicant wishes to update the labeling for an approved drug, the addition of an established pharmacologic class term to the Indications and Usage section must be proposed and submitted in a prior-approval labeling supplement.

The full draft may be viewed here.