Patents on Small-Molecule Drugs Approved by the US Food and Drug Administration, 1990-2019

Among nearly 2,000 small-molecule drugs approved by the FDA from 1990 to 2019, the mean number of patents listed in the Orange Book rose from 2.1 to 6.9 per drug. Nonprimary patents on formulations, methods of use, and delivery devices accounted for 84% of listed patents, 87% of those litigated against generic manufacturers, and 96% of those issued after FDA approval. The gap between a drug’s first- and last-to-expire patents also grew from a mean of 2.0 years to 6.1 years during this period. Limiting the number of continuation patents that can be asserted in litigation and increasing USPTO scrutiny of post-approval patents may be needed to ensure timely generic competition.