Feeling Evergreen: A Case Study of Humira’s Patent Extension Strategies and Retroactive Assessment of Second-Line Patent Validity

Abstract

The United States pharmaceutical landscape has been shifting considerably throughout the 21st century, resulting in higher drug costs and smaller new product pipelines. One factor is the increased prevalence of patent evergreening and patent thickets. Patent evergreening occurs when a manufacturer files additional patents based on modifications to an existing product to extend patent protection period. Patient thickets occur when a manufacturer files multiple overlapping patents on different components of the same product. One of the first products to capitalize on this system was Humira, a rheumatoid arthritis drug. Humira’s manufacturer, AbbVie, has been granted over 130 patents, resulting in a market exclusivity period stretching from launch in 2002 until 2023. The aim of this investigation is to determine the impact of Humira’s evergreening strategy on the rheumatoid arthritis market, and to conduct a patent validity assessment to aid in determining the social cost and impact of the additional years of exclusivity. This study analyzed Humira’s patents and available clinical trial data to assess evergreening strategy and quantify patient benefit and assessed financial metrics to determine the additional financial benefit to AbbVie per additional year of exclusivity. This investigation shows that Humira increased evergreening tactics in an attempt to prevent biosimilar competition and that subsequent formulations provided marginal patient benefit. Additionally, AbbVie was able to decrease research expenditures each year while increasing Humira’s list price. Ultimately, though this strategy was successful for Humira, it may not be replicable in the future due to evolving antitrust litigation.