Reporting of Drug Benefit in FDA-Approved Prescription Drug Labeling

Abstract

Obtaining an accurate understanding of the known benefits and risks of drugs is difficult, particularly when drugs first come to market. The most robust evidence is largely limited to pre-marketing studies (e.g., phase 3 trials), but the peer-reviewed literature describing these studies may be incomplete (e.g., with unpublished trials), and systematic reviews often have yet to be conducted. Despite their reputation as unhelpful, FDA-approved prescribing information (also known as “package inserts” or “drug labels”) should provide clinicians with a trustworthy source of information about new drugs that has been independently vetted. Previous research has assessed the quality of clinical trial evidence supporting recent FDA-approved therapeutic agents; however, how this information is reported to prescribers through drug labels has not been evaluated. Per guidance, labels are supposed to include key efficacy information including the magnitude of treatment benefit, i.e., “the effect that can be attributed to the drug” (measured as the difference between observed effects in new drug and control groups, presented as absolute and/or relative differences), and measures of precision and random error (confidence intervals and p values). We sought to assess the degree to which labels actually provided this information.