AbbVie Humira Patent Thicket Delays US Biosimilars Until 2023 Despite 2016 Patent Expiration and European Competition

AbbVie reached settlement agreements with eight biosimilar manufacturers that allowed immediate biosimilar competition in Europe starting October 16, 2018, but delayed all US market entry until 2023—seven years after Humira’s original patent expired in December 2016. The settlements ended patent litigation over AbbVie’s “patent thicket” of more than 130 patents covering the world’s best-selling drug, which generated $20 billion in global sales in 2018 and 60% of AbbVie’s revenue. While biosimilars entered European markets in 2018 and drove prices down, American patients and taxpayers continued paying monopoly prices for an additional five years due to AbbVie’s strategic exploitation of US patent system weaknesses that allowed the company to obtain 250 patents related to a single antibody discovered decades earlier.

Building the Patent Thicket: 132 Patents, 90% Filed After Market Launch

Before the 2016 expiration of the original patent for the Humira antibody (adalimumab), AbbVie applied for and obtained 132 patents related to formulation and manufacturing methods with expiration dates extending to 2034—more than three decades after Humira’s 2002 market launch. Within this “patent thicket,” 90% of the patents were issued in 2014 or later, despite Humira having been marketed for over a decade. Analysis revealed that AbbVie’s US patent portfolio consisted of roughly 80% non-patentably distinct (duplicative) patents linked through terminal disclaimers—a USPTO practice that allows companies to file multiple overlapping patents that would otherwise be rejected as obvious variations of existing patents. In contrast, AbbVie’s EU patent portfolio comprised only eight non-duplicative patents, exposing how US patent office rules enable pharmaceutical companies to manufacture legal obstacles that have no basis in genuine innovation.

The Litigation Strategy: Asserting 63 Patents Against Each Biosimilar

AbbVie asserted as many as 63 patents against individual biosimilar manufacturers, forcing each company to potentially litigate dozens of patents simultaneously at costs quickly running into tens or hundreds of millions of dollars. The strategy worked not because AbbVie’s patents were valid—many covered minor formulation changes and obvious manufacturing processes—but because the sheer number of patents made litigation prohibitively expensive and time-consuming. On average, nine to twelve times more patents were asserted against biosimilars in the United States than in Canada and the United Kingdom. Biosimilars entered Canadian and UK markets more quickly following regulatory approval than in the United States. This disparity revealed that AbbVie’s patent thicket was not protecting innovation but exploiting US legal system vulnerabilities to preserve monopoly profits.

The Settlement Terms: Market Division by Geography

Settlement agreements with Amgen, Samsung Bioepis, Mylan, Boehringer Ingelheim, Sandoz, and other biosimilar developers followed an identical pattern: AbbVie granted nonexclusive licenses allowing immediate European entry starting October 16, 2018, while US entry was delayed until dates ranging from January 31, 2023 to November 20, 2023, depending on company-specific arrangements. In exchange, biosimilar manufacturers would pay ongoing royalties to AbbVie for licensing patents that likely would not have survived validity challenges. The geographic market division was explicit: biosimilar manufacturers could compete in Europe where AbbVie’s patent thicket was much smaller, but were contractually barred from the US market—AbbVie’s largest and most profitable market—for five additional years despite FDA approval of multiple biosimilars as early as 2016.

The Two-Tier System: European Competition vs. American Monopoly Pricing

Within the global TNF-alpha inhibitors market worth $40 billion in 2018, Humira captured half of all sales at $20 billion, making it the highest-selling pharmaceutical product in the world. European patients gained access to competitively priced biosimilars starting in October 2018, while American patients continued paying monopoly prices through 2022. This transatlantic disparity in market entry revealed that AbbVie’s patent thicket was successful only in the United States, where USPTO rules allowed mass production of dubious secondary patents and where litigation costs made challenging patent validity prohibitively expensive even for well-funded biosimilar manufacturers. American patients and taxpayers—particularly Medicare and Medicaid—bore the cost of this five-year delay through continued payment of prices 50-80% higher than European biosimilar prices.

Patent System Gaming: Terminal Disclaimers and Duplicative Claims

AbbVie’s strategy exploited a USPTO practice called terminal disclaimers, which allows patent applicants to overcome “obviousness-type double patenting” rejections by filing multiple patents that expire on the same date. This practice was intended to prevent extending patent terms, but pharmaceutical companies discovered it could be weaponized to create patent thickets. By filing hundreds of overlapping patents with terminal disclaimers, AbbVie created a litigation obstacle course where challenging any single patent’s validity would not clear the path to market—biosimilar manufacturers would still face dozens of remaining patents. The Welch-Braun-Klobuchar bill, proposed in response to AbbVie’s tactics, would have limited companies to asserting a maximum of 20 patents in litigation, which would have restricted AbbVie to 24 patents instead of 105. The bill’s failure illustrated how legislative responses to patent abuse consistently lag behind corporate innovation in legal exploitation.

Antitrust Litigation and the “Scope of the Patent” Defense

Proposed class action litigation alleged that AbbVie monopolized the market in violation of Section 2 of the Sherman Act by acquiring and asserting a patent thicket to prevent biosimilar entry, and by entering “reverse payment” settlement agreements to delay competition. The Seventh Circuit affirmed dismissal of the claims, ruling that nothing alleged stated an antitrust violation. The decision reflected post-FTC v. Actavis judicial reluctance to second-guess patent settlements, even when the disparity between eight EU patents and 132 US patents for the same drug strongly suggested the US patents were obvious variations filed solely to block competition. The dismissal demonstrated how antitrust law struggles to address patent system abuse, particularly when companies can point to formally valid patents obtained through USPTO processes, even if those processes are systematically gamed.

Significance

The Humira patent thicket exemplified “evergreening”—pharmaceutical industry tactics to extend monopoly protection long after original patents expire through layers of secondary patents covering minor modifications. AbbVie’s success in delaying US biosimilar entry for seven years past patent expiration, while allowing immediate European competition, exposed the US patent system as uniquely vulnerable to gaming through mass filing of overlapping patents. The 132 US patents versus 8 EU patents for the identical drug product revealed that most of AbbVie’s US patents covered no genuine innovation but existed solely as litigation weapons. The five-year delay cost American patients and taxpayers billions in excess costs for a drug that was available at biosimilar prices in Europe. The episode demonstrated that pharmaceutical companies now invest more resources in legal strategies to extend monopolies than in scientific innovation to develop new therapies. AbbVie’s evergreening tactics became a template for the industry, showing that relatively modest investments in patent attorney fees could preserve billions in annual revenue. The Humira patent thicket illustrated how intellectual property law—designed to incentivize innovation—had been transformed into a mechanism for blocking competition and extracting monopoly rents from patients with chronic diseases requiring lifelong treatment.