prescription drugs

A recent study has quantified the wide disparity between the FDA-approved labelling of prescription drugs and real-world clinical practice.

When new prescription drugs are approved for marketing in the United States, the Food and Drug Administration (FDA) provides the accompanying drug-related information. Once the drug is in use in the population, clinicians and researchers observe new indications and evidence for safety. If this information is not submitted to the FDA by the drug manufacturer, the original labelling becomes out of date.

Off-label use of prescription drugs

Off-label is the term used when prescription drugs are used for an indication that differs from the FDA-approved labelling. As the approved labelling becomes outdated, clinicians begin to refer to other sources of drug-related information.

Off-label use of anti-cancer prescription drugs is a common phenomenon. The National Comprehensive Cancer Network Drugs and Biologics Compendium (NCCN compendium) is the main source of drug-related information for physicians because of its updated content based on high-quality evidence.

Researchers from the Friends of Cancer Research in Washington, DC analyzed drug-related information for 43 anticancer prescription drugs. The objective of the study was to quantify the disparity between FDA labelling and NCCN compendium labelling of prescription drugs.

The researchers identified 43 anticancer prescription drugs that were approved for marketing between 1999 and 2001. The indications for each of these drugs were compared between the FDA-approved labelling and the NCCN compendium labelling. Their results were recently published in Therapeutic Innovation & Regulatory Science.

Among these anticancer drugs, they identified 99 FDA-approved and 451 NCCN compendium uses. From the total number of NCCN compendium indications, 198 were on-label uses and 253 were off-label uses.

Since the NCCN compendium evaluates the quality of evidence for off-label uses, the researchers deemed 231 off-label NCCN compendium recommended uses as “well-accepted off-label uses”. This term was defined by the researchers of the study as an off-label use with a high category of clinical evidence (category 1 or 2A).

The wide disparity of FDA-approved uses and real-world clinical practice presents a public health concern. The mission of the FDA is to communicate drug-related information to the public and to prescribers. However, with outdated information, physicians and patients will look into other sources of information. Although sources such as the NCCN compendium offer high-quality evidence, other sources may recommend off-label uses that are supported by lower quality evidence.

Attempts to update prescription drug labels have failed in the past

The FDA has recognized the importance of off-label uses and has attempted to facilitate updating prescription drug labelling. These attempts have failed in the past because the responsibility for drug manufacturers to provide updated information on drug effectiveness is a voluntary process.

Disparities between drug labels and real-world practice present a public health concern

A wide disparity exists between FDA labelling of prescription drugs and real-world clinical practice. This presents a public health concern because the FDA labelling is a valuable source of drug information for doctors and patients. The updated prescription drug uses in FDA labelling will allow patients and doctors to identify drug indications that are supported by the highest quality evidence.

Written by Jessica Caporuscio, PharmD

Reference: Shea MB, Stewart M, Van Dyke H, et al. Outdated Prescription Drug Labeling: How FDA-Approved Prescribing Information Lags Behind Real-World Clinical Practice. Ther Innov Regul Sci. 2018

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