By: Alexander Okun

  On April 17, 2025, the non-profit Initiative for Medicines, Access, and Knowledge (“I-MAK”) published a report detailing the tactics that two pharmaceutical companies use to maintain their monopolies for their popular diabetes and obesity drugs. The two drugs are Semaglutide (marketed by Novo Nordisk as Ozempic, Rybelsus, and Wegovy) and Tirzepatide (marketed by Eli Lilly as Mounjaro and Zepbound). According to I-MAK, Novo Nordisk and Eli Lilly will effectively extend their patent-based monopolies on these drugs for up to a decade. The tactic of  “patent thickets” is not new to the pharmaceutical industry, but its potential economic impact as applied to these products (known collectively as “GLP-1” drugs) could be on a scale previously unseen. Given the adverse impact this could have on US patients, the need for legal reform is greater than ever.

“Patent Thickets” and Their Uses

A US pharmaceutical patent provides 20 years of protection, after which other manufacturers can produce generic versions of the drug. However, drug companies often file an array of patents for aspects beyond the drug’s core ingredients (called a “patent thicket”) like the method of administration. Subsequent changes to the product may also get patented (known as “secondary” or “follow-on” patents) but can be as minor as adding a dose counter to the injection device. Follow-on patents can also protect purportedly “new” applications of a drug without making any changes, even though those “novel” uses were  disclosed in the initial patent. For example, Eli Lilly’s Mounjaro is approved to treat diabetes while Zepbound is approved for weight loss even though Tirzepatide’s original patent disclosed both uses.

This practice is neither novel nor unique to the GLP-1 market: a 2018 report by I-MAK found that in 2017, the top 12 grossing medications in the US had an average of 71 active patents each, extending each drug’s protection for an average of 18 years. However, the profitability of those extensions is miniscule relative to the potential with GLP-1 drugs. Whereas the top-selling drug in I-MAK’s 2018 report, Humira, produced roughly $200 billion in revenue in its first 20 years, the GLP-1 market is projected to reach $150 billion in annual revenue by 2030. Novo Nordisk has already extended its patents for Ozempic and Wegovy by five years (expiring in 2031), which I-MAK says will deliver $166 billion in additional profits. As of now, patent thickets have effectively extended the protections for Semaglutide by 10 years (expiring in 2042) and Tirzepatide by five years (expiring in 2041). 

Potential for Reform

High drug prices are a perennial issue in US politics, and two proposals appear most promising in preventing further abuses of the patent system. The first approach is to limit the number of patents that can be cited in an infringement lawsuit. This would reduce the deterrent value of patent thickets by limiting the complexity of infringement actions (therefore defendants’ costs) and reducing plaintiffs’ likelihood of succeeding. The Affordable Prescriptions For Americans Act would implement this strategy, and on April 10 it was placed on the Senate’s legislative calendar. However, some analysts say the bill’s exemptions and waivers could make it largely ineffective.

A second option is to crack down on petitions that delay the approval of generic drug versions by using the filer’s patent thickets. The “Stop STALLING Act,” would enable the Federal Trade Commission (“FTC”) to sue filers if it deems a petition “objectively baseless” and intended to “interfere with the business of a competitor.”  However, the requirement of government intervention creates greater administrative costs and potential inconsistencies in enforcement. On April 10 the Stop STALLING Act was also placed on the Senate’s legislative calendar. While both bills have potential and bipartisan sponsorship, they have failed to garner sufficient support in their past iterations. Last year the Affordable Prescriptions for Patients Act passed the Senate unanimously but was never scheduled for a vote in the House of Representatives; the Stop STALLING Act never received a vote in the Senate whatsoever. Hopefully, the resounding success of GLP-1 drugs despite their exorbitant pricing will trigger public interest broad enough to provoke Congressional action.