Is Bioequivalence a Sufficient Measure of Equivalence?

Abstract

This article reviews the U.S. Food and Drug Administration (FDA) regulation of generic medications—specifically, the use of bioequivalence to compare generic and brand prescriptions. New or “brand” drugs are subjected to extensive review by the FDA before they can be marketed to the public. Generics, which are posited to be identical to brands, are subject to a less extensive review process and must prove only that the generic is the “bioequivalent” (BE) of the brand drug. Generic medications are important because they comprise almost 80% of prescriptions filled in the United States and cost 80% to 85% less than brand drugs, playing a crucial role in patients’ access to cost-effective treatments. However, there is dissension about whether they can be interchanged with brand drugs without any consequences for the patient, especially for Narrow Therapeutic Index (NTI) drugs, which have precise dosage requirements. The regulatory designation of bioequivalence also has implications for doctor–patient relationships, patient outcomes, and patient legal rights. This article aims to establish that there is insufficient evidence to conclude whether using bioequivalence is adequate to determine whether two drugs can be considered equivalent given the medical and legal implications that flow from deeming two drugs equivalent.