Distinguishing and Predicting Drug Patents

Abstract

Responsive to calls from lawmakers, the USPTO has recently announced a broad set of measures to increase the quality of drug patents ex ante, before they are granted, as a way of in the US. However, there is currently no way to tell which patent applications cover inventions that will lead to FDA-approved drugs, potentially compromising the efficiency and effectiveness of the agency’s efforts. Nor is it known how drug patent applicants differ from others in their use of examination tactics such as those that increase the number of patents that cover a drug. We address these informational deficits predictively and descriptively through an analysis of patents issued in 2005-2015 that cover drugs as identified through their listing in the FDA’s “Orange Book.” We find that even within the same technology areas, patent applications that mature into drug patents differ from other patent applications along several dimensions, showing intensified use of continuations, terminal disclaimers, Track One examination acceleration, and applicant- submitted prior art. In particular, while we find only 4.7% of all patents included terminal disclaimers, 34.7% of drug patents did, and of drug patents that had an earlier-granted family member, 58% included terminal disclaimers. Applying machine learning models, we find traits publicly observable at publication and grant to be reasonably predictive of a patent’s eventual designation as a drug patent. A random forest model trained on publication characteristics is associated with an area under the curve (AUC) statistic of 0.83, which improves to 0.91 when grant characteristics are used. The AUC statistic for predicting the first patent associated with a drug to be listed in the OB based on grant characteristics is ~0.9, and for subsequent patents, it is 0.97.

Keywords: patents, administrative law, experimentation, controlled trials, patentable subject matter, empirical legal studies, patent reform, patent litigation, patent prosecution, civil procedure

JEL Classification: K20, L51, O31, O34