Understanding pharmaceutical patent thickets, exclusivity

What are pharmaceutical patent thickets?

A pharmaceutical patent thicket refers to a dense network of multiple, overlapping patents surrounding a single drug. Unlike traditional patents, which typically cover major breakthroughs, these overlapping patents often relate to minor improvements or changes to the drug. These modifications can include different formulations, dosages, methods of administration or new therapeutic uses.

Companies strategically use these secondary patents to create barriers that prevent or delay competitors, such as generic or biosimilar manufacturers, from entering the market. This strategy can significantly extend a drug's profitability long after the original patent has expired.

At the heart of many pharmaceutical patent thickets are continuation patents. These patents stem from previously filed "parent" patents and do not introduce new inventions. Instead, they narrow the original patent claims, often specifically targeting competitors' potential products or methods. An important variant is the Long Continuation Patent (Long CON), filed several years after the original patent to reinforce market exclusivity further.

Between 2001 and 2019, pharmaceutical companies tripled their average patent filings per active ingredient, from fewer than 2 to nearly 6 patents. Despite comprising just 8.3% of total patents, Long CONs are involved in 36% of patent litigations for small-molecule pharmaceuticals, underscoring their significance, according to an empirical analysis.

How pharmaceutical patent thickets differ from other industries

While patent thickets are not exclusive to the pharmaceutical industry, the way drug companies utilize them is distinct in the following ways:

• Lack of cross-licensing. Unlike technology companies that frequently cross-license patents, pharmaceutical companies rarely share patent rights. Pharmaceutical patents typically function as a barrier to entry, directly blocking competitors from launching competing products.
• Strong regulatory environment. Pharmaceutical patents are often strategically listed in FDA databases like the Orange Book (for small molecules) and Purple Book (for biologics). These listings can trigger automatic delays in generic or biosimilar approval if the brand manufacturer files a patent lawsuit, complicating and postponing the entry of lower-cost alternatives and effectively extending market exclusivity beyond the initially granted term.
• Highly concentrated markets. With fewer major players, the pharmaceutical industry faces high financial stakes for maintaining market exclusivity, encouraging aggressive patenting strategies to preserve market dominance.

AbbVie's Humira is an example of patent thickets

To illustrate how pharmaceutical patent thickets are being leveraged to extend market exclusivity, take AbbVie’s biologic medication Humira (adalimumab) as an example. Initially approved in 2002, Humira faced the expiration of its original patent protection in 2016 and its regulatory exclusivity in 2014. However, AbbVie successfully delayed biosimilar competition for decades by building an extensive secondary patent portfolio before finally losing exclusivity in 2023.

Roughly 79% of Humira’s patents were continuation patents strategically filed as initial exclusivity approached its end. These secondary patents included specific dosing regimens and unique formulations, creating significant legal and practical hurdles for competitors. As a result, AbbVie secured around $74 billion in revenue after its original patent expired.

How to navigate patent thickets

Organizations must adopt a more proactive approach to handling patent thickets to avoid regulatory or legal pitfalls. To help protect valuable assets, there are several ways pharmaceutical companies and industry stakeholders can actively manage patent thickets:

• Early risk assessment. Regularly evaluating patent portfolios to identify potential legal risks and vulnerabilities helps manage litigation exposure proactively. This can involve strategic filing of patents and careful management of potential infringement claims.
• Engaging regulatory processes. Understanding regulatory listings and aligning patent strategies with regulatory timelines can optimize the commercial value of drug patents.
• Competitive intelligence. Regularly monitoring competitors' patent activities helps identify strategic threats or opportunities and guides innovation strategies to maintain a competitive edge.
• Staying informed of policy changes. Awareness of evolving regulations or legislative measures aimed at reducing patent thicket abuses allows pharmaceutical companies to adjust strategies accordingly, ensuring compliance and minimizing disruption.

Pharmaceutical patent thickets profoundly impact drug pricing, competition and access to affordable medicines. By layering secondary and continuation patents -- often on minor changes to formulations or delivery methods -- companies can extend market exclusivity well beyond the original patent’s expiration. While this tactic can be lucrative, it also fuels growing concerns about anti-competitive behavior and delayed access to lower-cost generics and biosimilars.

To operate effectively in this type of high-stakes environment, companies must find a balance between protecting innovation and avoiding exploitative intellectual property strategies. This means going beyond defensive patenting to embrace deliberate approaches to litigation risk, regulatory filings, competitor monitoring and policy shifts.

Alivia Kaylor is a scientist and the senior site editor of Pharma Life Sciences.