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Estimating Costs of Market Exclusivity Extensions For 4 Top-Selling Prescription Drugs in the US

Hong D, Tu SS, Beall RF, Russo M, Rome BN, Kesselheim AS, Sarpatwari A

JAMA health forum, 2025

2 citations

Abstract

Importance: Brand-name drugs in the US are sold at high prices during market exclusivity periods defined by their patents, before prices are lowered by generic competition. Drug manufacturers use several strategies to extend these market exclusivity periods and delay generic competition, including obtaining overlapping thickets of patents.

Objective: To estimate excess US spending associated with delays in generic competition due to extended market exclusivity for 4 top-selling drugs.

Design, setting, and participants: This retrospective serial cross-sectional study focused on 4 top-selling drugs that experienced new generic competition between 2014 and 2018 to allow enough time for determining postexclusivity price trajectories: imatinib (Gleevec, cancer), glatiramer (Copaxone, multiple sclerosis), celecoxib (Celebrex, arthritis), and bimatoprost (Lumigan, glaucoma). Drug monthly spending data from 2011 to 2021 were retrieved from a large commercial claims database (Merative MarketScan) and a random sample of Medicare beneficiaries with at least 1 month of Medicare Parts A, B, and D coverage and adjusted for estimated rebates obtained from SSR Health, LLC. The analysis was performed between March 2023 and January 2024.

Exposures: Extended market exclusivity was calculated as the time between expiration of the key patent and first generic marketing.

Main outcomes and measures: The primary outcome was net monthly national drug spending in commercial insurance and Medicare…

How strong is the evidence?

Evidence Hub reads this as a cross-sectional, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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