The Paradox of Legal Equivalents and Scientific Equivalence: Reconciling Patent Law's Doctrine of Equivalents with the FDA's Bioequivalence Requirement

Contrary to popular perception, generic drugs often enter the market before the patents covering their brand name counterparts have expired by making slight changes to the drug to avoid the brand name patent. These generics face a paradox: the U.S. Food and Drug Administration (FDA) requires that the generic "not show a significant difference" from the reference product, while patent law requires that the generic have "substantial differences" as compared to the reference product. The generic must be bioequivalent, but not legally equivalent, to the brand name drug. This paradox occurs frequently in the courts but has never been discussed in the literature.

This Article analyzes every case to date involving this equivalence paradox to create a normative theory explaining and predicting courts' treatment of these cases. It then explains the implications for patent law. Namely, it demonstrates how courts use these cases as an opportunity to tailor the scope of the patent based on its ability to provide ex post incentives for commercialization and development. Finally, this Article discusses the broader implications of the paradox on FDA law and concludes that these cases demonstrate that, while courts are increasingly skeptical of evergreening, the paradox impedes progress towards cheaper, safer medicine.