New research published in JAMA quantifies how drugmakers have built dense webs of patents around small-molecule medicines. Between 1990 and 2019, the average number of patents per drug approved by the FDA more than tripled, from 2.1 to 6.9. The study, led by S. Sean Tu of the University of Alabama, analyzed 1,981 small-molecule drugs and 10,940 associated patents, with nonprimary patents—those covering formulation tweaks, delivery devices, or methods of use—accounting for 84% of the total.
These extra filings create what the researchers call a "patent thicket." Though they generally do not involve a drug's active ingredient, they extend the period during which a drug remains under patent, from an average of two years in 1990 to 6.1 years in 2019. Because brand-name firms can charge monopoly prices while patents hold, the authors argue the growth in nonprimary patents likely limits price competition and delays generic entry, without meaningful clinical advancement.
Prescription drug spending in the U.S. rose from $291 per capita in 1990 to $1,084 in 2019, after adjusting for inflation. The study did not directly measure delays in generic availability, and drugmakers often argue the extra patents do not hold up generics—but the authors note those arguments often rely on pre-2010 examples. They call for stricter review by the U.S. Patent and Trademark Office, laws limiting minor add-on patents, and court-ordered disgorgement of profits from patent abuse.