GLP-1 receptor agonists (GLP-1RAs) were initially approved for diabetes treatment (e.g., Ozempic®) but have revolutionized weight management (e.g., Wegovy®) and are now being explored for treating a wide range of health conditions. Discovering drugs with pleiotropic effects beyond their original purpose can facilitate drug repurposing and extend the market lifespans of existing drugs. However, leveraging newly discovered pleiotropic effects of existing drugs requires careful consideration of intellectual property strategies. This article provides strategic considerations for obtaining patent protection for new uses for old drugs such as GLP-1RAs.

The Extended Lifespan of GLP-1 Receptor Agonist Drugs from the Discovery of Pleiotropic Effects

Glucagon-like peptide-1 (GLP-1) was first discovered in the 1980s as a regulator of glucose levels. Further research led to the creation of a stabilized GLP-1RA called semaglutide, the active ingredient in Ozempic®, a successful diabetes treatment, and in Wegovy®, a revolutionary body weight management drug. Moreover, recent clinical studies and real-world clinical data have revealed broader pleiotropic effects of these drugs, opening doors for repurposing and extending the commercial lifespan of these drugs. For example, a recent study published in Nature Medicine (Jan. 20, 2025) used clinical data to analyze the primary intended effects of GLP-1RAs and secondary effects across multiple health conditions. This study uncovered potential applications of GLP-1RAs in reducing the risks of neurocognitive disorders, gastrointestinal issues, hypotension, syncope, interstitial nephritis, and drug-induced pancreatitis. In addition, a clinical trial published on Feb. 12, 2025, in JAMA Psychiatry, found that semaglutide can significantly reduce alcohol craving.

Discovering new clinical approaches for existing and approved drugs provides opportunities to extend the lifespan and market potential of the existing drugs, as shown for GLP-1RAs and other pleiotropic drugs. In the case of GLP-1RAs, patent protection has been successfully obtained for new uses and formulations based on discoveries of new clinical effects. In fact, many patents covering GLP-1RAs are drug-device combination patents or formulations adapted for particular administration routes, such as oral or subcutaneous formulations.

As shown for GLP-1RAs, the discovery of pleiotropic effects can effectively extend the lifespan and markets of drugs by facilitating repurposing. However, patenting repurposed drugs can be challenging and requires careful consideration of patent prosecution strategies.

Patent Prosecution Strategies for Repurposed Drugs

Patenting a new use for existing drugs can be challenging because the claimed new use may be implied or considered obvious based on the known characteristics and mechanisms of the existing drug. See, e.g., In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990) (stating “[i]t is a general rule that merely discovering and claiming a new benefit of an old process cannot render the process again patentable.”) A new use can also be found obvious if prior art discusses similar uses of related drugs. Still, the new use can be patented if the prior art does not mention using the same active agent for the same clinical indication, as explained in Eli Lilly and Co. v. Teva Pharmaceuticals International GmbH, No. 20-1747 (Fed. Cir. 2021).

Below are considerations and strategies for overcoming challenges in patenting existing drugs and turning the discovery of pleiotropic drug effects into patentable claims.

1. Discoveries of clinical benefits or their underlying mechanisms are not patentable but may suggest patentable uses or formulations. 

The Federal Circuit has found that claims directed to new results obtained with a known method are inherently anticipated and, therefore, unpatentable if practicing the known method would necessarily produce the claimed results. See In re Woodruff and King Pharmaceuticals, Inc. v. Eon Labs, Inc., 616 F.3d 1267, 1275−76 (Fed. Cir. 2010). In King, the challenged patent claims were directed to beneficially increase the bioavailability of a drug when the drug was ingested with food. However, the prior art contained instructions for taking the same drug with food. Accordingly, the Court in King found that the claims relating to increasing bioavailability by food ingestion were inherently anticipated and invalid. The Court in King also clarified that the inventor’s ability to describe the underlying scientific principles or mechanisms, which was admittedly unknown or undisclosed in the prior art, does not confer patentability. Id. at 1328.

Moreover, it is usually unnecessary to disclose mechanisms’ underlying claimed inventions because understanding the principles underlying a claimed invention is not necessary. For example, Eames v. Andrews (The Driven-Well Cases), 122 US 40, 55–56 (1887) held that even though “the inventor did not know what the scientific principle was . . . . [t]hat does not vitiate the patent.” See also Radiator Specialty Co. v. Buhot, 39 F.2d 373, 376 (3d Cir. 1930) (explaining that “[i]t is with the inventive concept, the thing achieved, not with the manner of its achievement or the quality of the mind which gave it birth, that the patent law concerns itself.”). Hence, it may be beneficial not to disclose mechanisms’ underlying claimed inventions because mechanisms could be used to explain why the invention is obvious in some cases.

Thus, stakeholders should carefully consider if the discovery of new mechanisms or effects implies new method steps (e.g., specific administration routes), formulations, dosages, and treatments of different indications or patient populations to ensure the discovery can be covered by patentable claims as further discussed below.

1. Discoveries of new formulations or devices for delivering an existing drug can be eligible for patenting.

The Federal Circuit found a patent for a new formulation containing an existing drug valid in Endo Pharmaceuticals Solutions, Inc. v. Custopharm Inc., 894 F.3d 1374 (Fed. Cir. 2018). For example, many patents covering the GLP-1RAs claim a combination of a delivery device and an active agent. In other cases, a new formulation adapted for different administration routes, such as subcutaneous or oral administration, can be sufficient to obtain a new patent.

2. The discovery of a new patient population to be treated by an existing drug can be patentable.

The Federal Circuit explained in Sanofi v. Watson Labs Inc., Case Nos. 16-2722; -2726 (Fed. Cir., Nov. 9, 2017) that the asserted prior art did not provide the required “reasonable expectation of success” for treating the claimed patient population. Therefore, if a drug’s discovered effects or mechanisms indicate that an existing drug could be used to treat a novel patient population, this particular patient population could contribute to the novelty and non-obviousness of the patent claims for the new use.

3. The discovery of a new administration route or dosing schedule for an existing drug can be patentable.

The challenge of inherent disclosure can be overcome by adopting a different method of drug administration for the new use. The Federal Circuit found in Perricone v. Medicis Pharm. Corp., 432 F.3d 1368, 1378–79 (Fed. Cir. 2005) the prior art use did not teach the “topical application to skin sunburn” required by the claimed new use. In Perricone, the patent claims at issue were directed to treating skin sunburn or damaged skin by topically applying a composition that was known in the prior art to the skin. However, the prior art did not disclose topical application to the sunburned or damaged skin, so the Federal Circuit found the prior art did not inherently anticipate the claims. Accordingly, identification of specific new ways of administering the drugs or dosing schedules may provide options for addressing inherent anticipation of new uses for existing drugs. 

Conclusion

The recent dramatic success of GLP-1RAs in weight management and the reports of numerous beneficial pleiotropic effects of this class of drugs highlight the immense potential for repurposing drugs to extend lifespan and markets of drugs. Maximizing the value of GLP-1RAs and next-generation pleiotropic drugs will demand effective navigation of data management and analysis, deals and licensing, regulatory exclusivity, and strategic patent prosecution.

With the rise of AI-driven clinical data analysis, stakeholders have unprecedented opportunities to detect pleiotropic effects and new uses for existing drugs to extend their lifespan and market. Securing robust and timely patent protection for new uses will be critical to extend the commercial lifespan of existing drugs.