Brand-name drugs have periods of market exclusivity before generic competition begins. Due to high brand-name drug prices charged during this period, market exclusivity is an important determinant of US prescription drug spending. We used claims data to estimate the market exclusivity period for 264 small molecule and 4 biologic drugs that faced new generic or biosimilar competition from 2012-2018. Exclusivity periods were longer for biologics compared with new small molecule drugs (median 21.5 vs. 14.4 years, P = 0.02), longer for drugs with annual revenue < $75 million compared with those with revenue ≥ $500 million (16.6 vs. 14.2 years, P = 0.01), and shorter in cases for which the first generic was granted 180 days of exclusivity, which is an incentive designed to expedite generic competition (14.1 vs. 15.9 years, P < 0.01). Modified versions of existing products had shorter exclusivities than new drugs (9.9 vs. 14.5 years, P < 0.01), with variation by route of administration, therapeutic area, and use of expedited approval pathways. Exclusivity periods for new drugs ranging from 13-17 years are similar to older estimates, but longer exclusivity among the small number of biologics in the cohort raises concern that overall median exclusivity may lengthen in the future because biologics represent a larger fraction of new drug approvals over the last decade than they did the previous decade. Unnecessarily long exclusivity periods delay patient access to lower-priced medications, and policymakers should consider options to encourage timely competition, particularly among biologic drugs.
© 2020 The Authors Clinical Pharmacology & Therapeutics © 2020 American Society for Clinical Pharmacology and Therapeutics.