Evergreening: The Backbone of Pharmaceutical Patents
This blog introduces Evergreening and its impact on the pharmaceutical industry's control of their intellectual property.
The race to produce new medication has become tighter than ever, with patents serving as the foundation of the pharmaceutical industry. It allows these companies to possess temporary monopolies, spurring them to invest billions of dollars in innovation and research. This has ballooned the global pharmaceutical industry to a worth of $1.6 trillion dollars in 2023, and a projected value of $2.35 trillion by 2030. 21. Statista, Global Pharmaceutical Industry Overview, https://www.statista.com/topics/1764/global-pharmaceutical-industry/#topicOverview (accessed Oct. 31, 2025). In creating new life saving-treatments, this unique protection creates a tension between innovation and access; as when a patent expires, other companies can create generic versions that drive prices down. This improves affordability, but cuts into margins for the companies that discovered the medicine, leading them to employ legal strategies to delay this competition through a process known as evergreening.
Evergreening is a system by which pharmaceutical companies can create minor modifications on already existing drugs to extend the patents on them. These modifications can range from new formulations, delivery methods, or therapeutic indications, which allow for these companies to retain control of their market share in that field. Critics of this policy may argue that it takes advantage of the patent system as slight changes offer longer advantages with no significant benefit to the consumer. Additionally, these critics argue that it decreases competition and promotes monopolies where the pharmaceutical companies can get away with controlling prices and access to products. Advocates, however, push back on these ideas by stating that the improvements are essential in the research and development process (R&D), where limiting their patentability would halt innovation and stop investment into new research. The cost to bring a new drug into market is astronomical, estimated to be over $2.6 billion dollars in a span of 10-15 years, accounting for the fact that less than 12% of drug candidates that enter clinical trials will get approval from the Federal Drug Administration (FDA). Joseph A. DiMasi, Henry G. Grabowski & Ronald W. Hansen, Innovation in the Pharmaceutical Industry: New Estimates of R&D Costs, 47 J. Health Econ. 20 (2016).dukespace.lib.duke.edu+2dukespace.lib.duke.edu+2. Companies file patents years before they can commercialize them, limiting their exclusive control of the market to 7-12 years, impacting profitability and funding for future research. Fortunately, Congress enacted the Drug Price Competition and Patent Term Restoration Act of 1984, otherwise known as the Hatch-Waxman act, which allows for limited patent term extensions so companies can recoup for time lost in the FDA approval process. Drug Price Competition and Patent Term Restoration Act of 1984, Pub. L. No. 98-417, 98 Stat. 1585 (Sept. 24, 1984). The act subsequently created the Abbreviated New Drug Application process known as ANDA, which allowed manufacturers of generic medication to rely on the brand name counterpart’s safety and efficacy data. See 21 U.S.C. § 355(j) (2022). Generic drugmakers now do not have to create new trials for medications, reducing their costs; however, it resulted in more complex litigation around secondary patents. The system was designed to promote balance in the innovation of the field and increase competition, but many companies have used it to file new patents to cover alternative formulations, dosing, combinations, etc to legally extend their exclusive control under the scope that it is a beneficial contribution to the consumer.
A common method concerning evergreening is the patenting of new formulations and delivery systems for existing active ingredients in the market. Pharmaceutical giant Eli Lilly used this method to extend their patent protection on Prozac (fluoxetine), by filing a patent for R-fluoxetine, a non-superimposable mirror image formulation known as an enantiomer. They then were able to market the enantiomer as Sarafem, targeting premenstrual dysphoric disorder. See U.S. Patent No. 5,708,035 (filed Jun. 18, 1993). Another case of this is where Purdue pharma reformulated OxyContin, adding abuse-deterrent properties, which extended and secured new patents on that medication. These modifications do yield public health benefits, as they improve various aspects of prescription medication such as efficacy and safety; however, some would view these tactics as delaying generic medication development where these companies could be focusing on the development of new medications instead of modifying old ones.
Pharmaceutical companies may also create new therapeutic uses for existing drugs, which falls under extension criteria for the Hatch-Waxman act. Drug Price Competition and Patent Term Restoration Act of 1984, Pub. L. No. 98-417, 98 Stat. 1585 (Sept. 24, 1984). Pfizer found that their drug Gabapentin (Neurotonin) had another use, originally meant for treating epilepsy, it was then found to be effective at treating neuropathic pain. Pfizer then used this to file additional patents to extend the time they had over the drug. See U.S. Patent No. 6,054,482 (filed Jan. 25, 1995). Similarly, Nexium (esomeprazole) was a purified version of Prilosec that was originally marketed for gastric ulcers but expanded its use to general acid reflux disease symptoms. See U.S. Patent No. 5,714,504 (filed Jan. 23, 1995). This example emphasizes that even small differences in use in a similar category allow these companies to extend their patents through evergreening. This process of protecting patents help encourage more research into known medications, formulating new uses for repurposing them or increasing their efficacy.
Companies can also apply for a new patent through combinations of a drugs’ active ingredient or establishing a new delivery mechanism. An example is the prescription inhaler Advair Diskus, used in the long-term maintenance treatment of asthma and chronic obstructive pulmonary disease, which combines salmeterol and fluticasone. The company behind the drug, GlaxoSmithKline was able to use the combination drug to extend their exclusive control of each drug beyond the individual ingredient patents. See U.S. Patent No. RE40,045 (filed Sep. 03, 2004). Another drug that took advantage of this route is Humalog KwikPen, a type of insulin pen, having had multiple different patents due to small changes in its injection mechanism, where the patent was not give necessarily due to the main ingredient itself. See U.S. Patent No. 770,038 (filed Jun. 26, 2014).
These examples exemplify the many ways pharmaceutical companies can extend their patents over their intellectual property, whether it be related to the actual formulation of a drug, or the mechanism of its delivery and other factors. The use of evergreening is a delicate balance, trying to maintain progress in the medical community while keeping fairness in competition for consumers. One of the more well-known examples of evergreening is Humira (adalimumab) which was developed by AbbVie. It was approved by the FDA in 2002 for the use in Rheumatoid Arthritis. However, several years later, it was approved for the use of various autoimmune disorders, such as Crohn’s disease and Psoriasis. In the period following its first patent until 2022, the company received 130 patents related to Humira, ranging from the changes in formulation, dosing, manufacturing, and delivery mechanisms. See U.S. Patent No. 6,090,382 (filed Feb 02, 1996), U.S. Patent No. 8,992,926 (filed Sep. 26, 2014), U.S. Patent No. 9,067,992 (filed Dec. 08, 2014).
These filings then delayed competition for biosimilar products in the United States until 2023, where in other countries such drugs had already become available. This issue eventually made its way in front of members of Congress, and the Federal Trade Commission (FTC), where they described AbbVie’s use of evergreening as a packet thicket, creating a complex web of patents that deter any competition from arising due to fear of litigation. U.S. House Comm. on Oversight & Reform, Staff Report, Drug Pricing Investigation (2021), https://oversightdemocrats.house.gov (last visited Oct. 31, 2025). AbbVie claims that each patent arose out of genuine innovation where its’ revenue generated from Humira, one of the world’s most best-selling drugs, helped fund research that released critical new therapies such as Skyrizi, and Rinvoq. 11. AbbVie Inc., Annual Report (Form 10-K) for the year ended December 31, 2022 (2023). SEC+1. Their claims highlight a valid part of the research process, as innovation is expensive and the need to fund new discoveries cannot be overlooked just to restrict exclusivity.
Under U.S. federal law, a patent must satisfy novelty, non-obviousness, and utility. See 35 U.S.C. §§ 101–103 (2022). Cases involving evergreening usually fall under the nonobviousness requirement for the conditions regarding patentability. This clause overlooks if the invention “would have been obvious to a person having ordinary skill in the art at the time of innovation”. See 35 U.S.C. § 103. However, litigation has been raised in cases where there are trivial modifications made to the patented idea. In Pfizer Inc. v. Apotex Inc., the Federal Circuit ruled that Apotex’s patent was invalid due to its besylate salt form of the active ingredient amlodipine, used in the drug Norvasc. Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348 (Fed. Cir. 2007). The Court found that the salt form was an obvious variation of a known compound and highlighted how courts are hesitant to uphold patents with small improvements that do not hold any technical advantage. Id. This sentiment is reflected in KSR International Co. v. Teleflex Inc., where the Supreme Court stressed a flexible approach to nonobviousness, stating they were against granting patents for ordinary innovation. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007). These cases restrict the granting of these secondary patents and signify that courts value real innovation over those meant to delay competition or create small insignificant innovations.
Pharmaceutical companies must balance profits to fund research and development with access to medications. R&D is expensive, having long developmental cycles and low success rate. Without reliable and stable intellectual property protection, companies are unwilling to invest in niche or risky research areas. Drugmakers would base decisions strictly off their expected revenue and likelihood of achieving success rather than progression of scientific innovation or public benefit. Even though small innovations may appear minor in scope, the benefit to patients may be significant, such as reducing side effects or lowering reaction times. The FTC aligns with this sentiment, stating that patent protections must be “sufficiently robust” to satisfy the complex market that is pharmaceutical research and development. Federal Trade Commission, To Promote Innovation: The Proper Balance of Competition and Patent Law and Policy (2003).
Reducing the scope of evergreening could subsequently cause innovation to cease, especially in areas that are subject to economic fluctuation like antibiotics or rare diseases, as profit margins are low. Innovation is slow, small, and incremental as it builds on itself to make significant change in science. Inventions of sustained-release delivery mechanisms, safe effective drug coatings, and combination therapies all arose out of small incremental changes due to evergreening and patent protection. Evergreening can be viewed by critics as being anticompetitive; however, denying patent protections for small advances risks emphasizing that only large achievements should be patented, which would significantly alter the medical industry. There are ways to combat excessive patent layering, as the Hatch-Waxman Act enables generic drugmakers to take weak patents to court through Paragraph IV certifications. See 21 U.S.C. § 355(j)(2)(A)(vii)(IV) (2022). There have been cases such as FTC v. Actavis, Inc., where the federal government ruled that “pay-for-delay” would not be allowed to mask collusion in the market. FTC v. Actavis, Inc., 570 U.S. 136 (2013).
Evergreening is at the forefront of pharmaceutical policy as it governs how companies protect their intellectual property to fund their research and development while providing access to healthcare. In this way, it attempts to answer how to reward scientific progress in pharmacology without restricting competition and supporting monopolies. Although there are many critics of evergreening who see the process as a way of manipulating the patent system, the law offers many legal tools in combating this; whereas a ban would undermine the benefits a company receives to undergo research in expensive and risky therapies. This field is one where a single discovery can affect millions of lives, and the law must dictate it in a careful balance. When it is properly regulated, patent quality and transparency are at the forefront, encouraging genuine innovation rather than a legal strategy to stifle competition. Evergreening should not be eliminated but, rather, regulated so that companies focus on investing in safer, effective, and convenient therapies that advance innovation satisfying both public and private interests.