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

Importance Patent protection allows pharmaceutical companies to charge high prices for prescription drugs during periods of market exclusivity, and their expiration usually defines when generic competitors can enter the US market. Patents on drug active ingredients are classified as primary patents, while patents on formulations, methods of use, and delivery devices are nonprimary. Objective To evaluate how pharmaceutical patent portfolios for US Food and Drug Administration (FDA)–approved drugs have evolved over time. Evidence Review Patents on small-molecule drugs approved by the FDA from 1990 to 2019 were examined and assessed for changes in the number and types of patents per product. The additional duration of total patent exclusivity associated with each patent type was quantified, and how often patents of each type were enforced against generic manufacturers in litigation was determined. Findings The FDA approved 1981 small-molecule drugs during the study period, and manufacturers listed 10 940 patents on these drugs. The mean number of patents per drug increased from 2.1 in 1990 to 6.9 in 2019, driven primarily by nonprimary patents. The mean number of nonprimary patents per drug rose from 1.2 in 1990 to 5.6 in 2019. Nonprimary patents represented majorities of FDA-listed patents (84% [9236/10 940]) and litigated patents (87% [4586/5253]). Nearly all patents listed after drug approval were nonprimary (96% [4874/5064]), and these patents extended market exclusivity by a mean of 6.1 years (SD, 5.8 years) and a median of 4.7 years (IQR, 0.2-10.1 years). Conclusions and Relevance Pharmaceutical patent portfolios have grown over the last 2 decades. These portfolios have largely been built on nonprimary patents, which are then enforced against generic firms at higher rates than primary patents. Large patent portfolios can complicate routine generic competition and prolong periods of high drug prices.