The Illusion of Expiration: How Evergreening Undermines Patent Expiration in the GLP-1 Market

The American patent system’s purpose is — as clearly explained in the Constitution — “to promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries” [1]. Congress has used this authority to grant inventors the exclusive commercial rights to their inventions for up to 20 years [2]. This exclusivity is intended to support innovation by guaranteeing that an inventor can recoup development costs and profit from their inventions [3]. But as currently designed, the American patent system also permits less beneficial “evergreening” practices and “patent thickets” in the pharmaceutical industry, which shut out competition and raise the prices of life-saving treatments. These tactics are possible because of the many loopholes that can extend the 20-year maximum on patent exclusivity for drugs, leaving the system susceptible to abuse at the expense of Americans. Through a case study of Novo Nordisk’s semaglutide, an active ingredient in GLP-1 weight-loss drugs such as Ozempic or Wegovy, this article explores pharmaceutical patent extensions and argues they subvert the intent of the patent system as found in the Constitution and subsequent legislation.

Evergreening is the practice of maintaining pharmaceutical patents in near-perpetuity [4]. This can be achieved through patent extensions such as those introduced under the Hatch-Waxman Act, or through the repatenting of a drug with only marginal changes. For a patent to be successfully filed in the United States, it must meet four requirements, the two most important of which are novelty and “non-obviousness” [5]. For example, if I were to invent a new kind of pen, the new design itself could be patented as it represents a “novel” and “non-obvious” invention. However, if I then decided to attach a clip to the pen cap, that would not be a particularly novel or non-obvious improvement, so it isn’t likely patentable on its own. Patent thickets are a different strategy where corporations apply for as many overlapping “secondary” patents as possible. In pharmaceutical contexts, these can include method-of-use patents (e.g., patents on the oral ingestion of a medication), patents on related technology needed for drug application like injection devices, or patents covering drug manufacturing methods. These patents seek to prevent the entrance of generic versions of drugs onto the market by withholding the infrastructure surrounding the drug that is needed to produce, administer, or design similar drugs [6].

Novo Nordisk’s patent strategy in the United States has very effectively combined evergreening and patent thickets to prevent competition from generic versions of semaglutide at the expense of the American consumer. Novo Nordisk filed United States patent number 8,536,122 (’122), which covered a fairly narrow group of Semaglutide compounds optimized for commercial use, in 2012. That patent expired in March 2026 [7]. That marked the end of Novo Nordisk’s monopoly on semaglutide in the United States, right? You would imagine so, if Novo Nordisk’s exclusive commercial rights had expired along with its original patent. Novo Nordisk, however, filed a second, extraordinarily similar patent, United States patent number 8,129,343 (’343) in 2006, which the United States Patent and Trademark Office approved in 2012, granting the company 19 years of exclusive commercial rights set to expire in December 2030 [8]. This patent covered a broader range of semaglutide variants and includes essentially all of the compounds covered by the ’122 patent, with just enough novelty to be approved by the United States Patent and Trademark Office [9].

Of course, this is all legal. And in theory, this newer patent will only last 19 years. This and similar patents, however, can also benefit from a litany of extensions. Novo Nordisk can first apply for a five-year extension to the ’343 patent under the Hatch-Waxman Act of 1984, which will push the patent’s expiration date to December 2035 [10]. Under the Food, Drug, and Cosmetic Act, pharmaceutical companies can also qualify for three more extensions with relative ease, regardless of previous patent extension strategies [11]. The largest is a five-year exclusivity on abbreviated new drug applications (ANDAs) and new drug applications (NDAs) for drugs using compounds similar to those for which Novo-Nordisk originally received FDA approval [12]. Semaglutide could also be eligible for a three-year prohibition on FDA approval of competing drugs if Novo Nordisk can claim new clinical investigations that could examine new conditions to be treated with or dosage forms of the drug [13]. They can further apply for a six-month extension for the completion of additional pediatric studies of semaglutide [14]. If you’re doing the math, that’s 13 years and six months of extensions on a single patent, on top of the original 19 years of exclusivity. Pharmaceutical companies can also apply for a 30-month stay on the entry of generics into the market when their original drug or related patent has been filed under the FTC’s list of “Approved Drug Products with Therapeutic Equivalence Evaluations” (Orange Book), a process Novo Nordisk has already attempted to abuse [15]. With just these routine pharmaceutical patent extension programs, the total effective patent period on semaglutide could be extended to 36 years, almost double the original 20-year maximum period [16].

This extraordinary prolonging of commercial exclusivity is unique to pharmaceutical patents. What is it about this particular class of inventions that merits such generous privilege? Novo Nordisk already makes $16.4 billion in profit annually from semaglutides [17], so that 16-year extension could amount to hundreds of billions in profit at the expense of the American consumer [18]. For a drug with an estimated development cost of $2–4 billion [19], it goes completely beyond the original Constitutional intent of the patent system to “promote the Progress of Science” for a corporation to first earn between 80 and 160 times their development costs in revenue during the initial patent period, and earn a further 65 to 130 times development costs after a series of extensions with such low bars for qualification. Some may ask whether such exorbitant profits are necessary to balance the vast majority of drugs developed that never become profitable. Indeed, only around 14% of drugs developed by pharmaceutical companies are ever successfully brought to market [20]. But at an average development cost of only $72.5 million for a genitourinary drug up to $1.76 billion for pain and anaesthesia medication [21], pharmaceutical companies like Novo Nordisk can amass astronomical profits, far beyond what is needed to recoup costs and encourage further development [22].

But it’s not just long extensions on a few patents. Novo Nordisk also holds 152 “secondary” patents and has filed a total of 382 patent applications related to semaglutide [23]. These many patents form the basis of an extremely effective patent thicket that covers everything from injectable forms of semaglutides to specific manufacturing processes, drug formulations, and injector designs [24]. It would be nearly impossible for any drug maker hoping to produce a generic GLP-1 to avoid all of these patents at every stage of the process. Patent thickets are incredibly difficult to challenge in the United States and present a major obstacle to generic entry into the weight loss drug market.

In 2025, Novo Nordisk sued Mylan Pharmaceuticals for infringement of its patent thicket after Mylan filed an abbreviated new drug application (ANDA) for a generic semaglutide product [25]. Filing an ANDA with the FDA resulted in an automatic claim from Mylan under the Hatch-Waxman Paragraph IV patent challenge framework [26], claiming their new product does not infringe Novo Nordisk’s patents. In response, Novo Nordisk sued for five violations of method-of-treatment and formulation patents as well as violations of the core ’122 and ’343 patents, alleging that Mylan’s ANDA constituted infringement [27]. The courts ultimately held that Mylan, as a pharmaceutical company that does not directly treat or administer drugs to patients, cannot infringe upon Novo Nordisk’s method-of-use patent. They failed to rule, however, on Mylan’s potential infringement of either the ’122 or ’343 patents [28]. At first glance, this case appears to be a reduction in the strength of Novo Nordisk’s patent thicket, but the court’s assertion that if Mylan had directly sold to consumers, they likely would have infringed, the court protected Novo Nordisk’s consumer interests and maintained the core of the patent thicket.

This patent thicket means that even if Novo Nordisk miraculously lost its semaglutide patent, it would be years before generic competitors could enter the market. Novo Nordisk would no longer control the compound itself, but it would still control everything from the techniques to manufacture Semaglutide to the devices used to inject it, to even the concept of consumption in an oral format [29]. In practice, this amounts to a soft extension of commercial exclusivity beyond even the extraordinarily generous terms of the pharmaceutical patent system. These patents are not, on their own, problematic; it is entirely reasonable that companies and inventors are able to profit from their inventions. However, when dozens of these secondary patents are used in conjunction with evergreening practices, they become a critical lynchpin in undermining the original intent of the patent system.

We can see exactly how such a hypothetical might play out by turning north. In Canada, Novo Nordisk recently failed to refile its Semaglutide patent, resulting in the patent’s lapse. [30] However, Novo Nordisk still holds an additional 81 secondary patents in Canada that present a major barrier to entry for generics into the Canadian market [31]. This is a real-world example of the abuses of patent thickets playing out before our very eyes. Canada also faces many similar problems to the FTC Orange Book abuses in the United States. Canada allows for 24-month stays on a generic drug’s approval, which, while Novo Nordisk has not employed this particular tactic, is consistently abused by the Canadian pharmaceutical industry [32].

These tactics aren’t localized to North America, and many nations have taken further regulatory steps to address them. India has passed anti-evergreening statutes limiting patents only to novel drugs and to substances with a non-obvious and demonstrable improvement in efficacy over existing drugs [33]. These statutes have been used within India to challenge pharmaceutical giants and support the entry of generics into the market. They represent a light at the end of the tunnel, which could be an effective remedy to the current loopholes facing the U.S. pharmaceutical patent system.

Particularly, the Indian case Novo Nordisk v. Dr. Reddy’s Laboratories (2025) shows how evergreening can be effectively countered [34]. In April 2025, Dr. Reddy’s Laboratories (DRL) began manufacturing a generic Ozempic competitor, Olymviq. Novo Nordisk’s Indian patents were structured similarly to their American patents: They held one generic patent for a broad class of semaglutide, Indian patent number 262,697 (’697), which they sued DRL for infringement of. However, Novo Nordisk also held a previous Patent IN ’694 that had since expired. The compounds used in DRL’s Olymviq fell under both patents; however, because ’694 had expired, Novo Nordisk claimed infringement of the ’697 patent. DRL argued that IN ’697 was too obvious an improvement from IN ’694, and therefore, under India’s anti-evergreening statutes, the ’697 patent was invalid [35]. This meant that the difference between IN ’694 and IN ’697 became a key issue of the case. To determine the outcome, the Delhi High Court utilized a five-step standard for “obviousness” that asked whether someone “skilled in the arts” and of equal skill and knowledge to the inventors of IN ’694, would determine the difference found in the ’697 patent — a change of a single amino acid — to be a non-obvious change. The High Court ultimately held that the improvement to the compound identified in IN ’694 was obvious [36]. Thus, the new patent failed the non-obviousness test, opening the door to the entry of many generic semaglutides into the Indian market.

If the United States adopted similar anti-evergreening statutes to India’s, the patent system could be restored to its original purpose of safeguarding and encouraging innovation, while limiting anti-competitive practices that unnecessarily harm the consumer. The Hatch-Waxman and Food, Drug, and Cosmetic Acts’ loopholes would be closed, and our patent system would be less susceptible to the damage that evergreening and similar excessive patent protections inflict on American consumers.
One might argue that these extraordinarily generous protections for pharmaceutical patents in the United States are responsible for America’s incredible pharmaceutical innovation, which has produced wonder drugs like semaglutide. The United States, after all, is an extraordinarily profitable market for pharmaceutical companies, accounting for nearly half of all prescription drug sales globally [37]. You could argue, then, that this profit motive drives American innovation in pharmaceuticals. But this argument fails to hold water when you consider that drugs such as semaglutide would remain fantastically profitable even if confined to the still-generous 20-year maximum monopoly originally specified in the Patent Act. Novo Nordisk is a $167 billion corporation, largely from its flagship products Ozempic, Wegovy, and Rybelsus, all of which are based on semaglutide. Finding the next wonder drug would justify any company’s investment, regardless of whether the United States continues to tolerate predatory patent practices such as evergreening or patent thickets. Recalling the constitutional purpose of this system, to “promote the Progress of Science and useful arts…” we must ask whether extended monopoly is the only tool to achieve these aims. Could increasing federal research funding or improving the patent system's efficiency in evaluating applications incentivize innovation just as much as a monopoly?
Further, reducing these protections might actually encourage more innovation as companies seek to maintain exclusive commercial rights on compounds by demonstrating significant improvements in efficacy to avoid losing patent protection. Furthermore, as drugs such as semaglutide lose their exclusive rights, companies will need to develop new products to maintain their current profit margins, as the entry of generics into the market will certainly lower prices.

Luckily, American lawmakers are taking note of pharmaceutical patent abuses and taking steps to bring the patent system back in line with its original intent. The FTC has already begun, for example, to crack down on abuse of Orange Book protections. The Orange Book, officially the “Approved Drug Products with Therapeutic Equivalence Evaluations,” protects drug products — the compounds themselves, as well as medicines that use them and different methods of use — from generic competitors [38]. Inclusion in the Orange Book qualifies patents for a thirty-month stay of FDA approval of any ANDA or NDA related to the patent [39]. This is an extremely powerful regulatory protection for patent holders specifically designed to slow the entry of generics into the market. However, the system has increasingly been abused by pharmaceutical companies incorrectly filing patents that do not qualify under the Orange Book. In 2024 alone, the FTC issued over 300 challenges to Orange Book listings [40], including 36 to Novo Nordisk’s patent listings, 34 of which are related to semaglutide products [41]. As the FTC seeks to tighten Orange Book compliance, it is also taking major steps towards making pharmaceutical patents fairer and promoting a patent system that better serves its purpose of promoting innovation.

Lawmakers, too, recognize the crisis in the patent system. In 2022, Congress passed the Inflation Reduction Act (IRA), with provisions explicitly regulating the long-term monopolization of pharmaceutical products [42]. The law mandates that holders of long-term drug monopolies (companies with still-active patents over 16 years old) enter into price negotiations with the government, resulting in reduced incentives to maintain monopolies [43]. This law mandates price negotiations but does not alter the underlying patent system. It’s a half-measure, still allowing protracted monopolies, but it doesn’t do so at the expense of the most vulnerable consumers. It’s a pragmatic solution that erodes the power of evergreening and encourages patent strategies to rely more on secondary patents that are entitled to less generous protection. Limiting the profitability of the drug itself encourages companies to benefit from their secondary innovations, which have far less generous patent protections than the substance itself, while ensuring affordable access to life-saving medication. This means that generics are more able to enter the market and strike at the heart of the problem, namely, evergreening.

20-years is already such a long time to hold patent authority, so it’s reasonable to question whether an additional 16 years would make much difference. But 20 years is already a historic deviation from the precedent. It is significantly longer than the time granted in the Patent Act of 1790, which assigned inventors exclusive commercial rights for 14 years [44], and then the Patent Act of 1836’s language, which assigned a period of 14 years again [45]. The Patent Act of 1870 actually emphasized shorter terms, directing periods of three years and six months, seven years, or fourteen years at the longest [46]. In fact, patent length would only be extended to its current 20-year length in 1999 with the American Inventors Protection Act [47]. If anything, the 20-year length is already an overly liberal maximum. If we instead think about patents in terms of the original 14-year maximum, the 36-year limit represents 2.5 times the length that our founding fathers intended for the patent.

Novo Nordisk is not the only company that takes advantage of loopholes in our patent system; nearly every major pharmaceutical innovator uses them. They are widespread and systematic, and indicative of an ailing patent framework that is incapable of maintaining its constitutionally defined purpose [48]. Evergreening and patent thickets undermine our patent system, which upholds the twenty-year limit in all other respects and was originally designed to limit anti-competitive behavior that abuses patent protections.

The stakes in the pharmaceutical industry are particularly high, with many people’s lives reliant on medication prices and the promise of future innovation. This is all the more incentive to get pharmaceutical patents right and to not tolerate any abuse or adulteration of the patent system’s original purpose. And this is exactly the kind of danger our past legislatures foresaw, which is why time and time again our legislators, justices, and executives promoted a limited patent system. The U.S. is responsible for 43.7% of new molecular entities and 42% of prescription drug spending [49], so if we can reform the patent system by limiting practices such as evergreening and patent thickets that stifle innovation and artificially raise prices, we would make significant progress in protecting the nearly one in four Americans who struggle to afford medication [50].

Footnotes

[1] U.S. Constitution, art. 1, sec. 8, cl. 8.
[2] LII / Legal Information Institute. “Copyright and Patent Power.” Accessed April 23, 2026. https://www.law.cornell.edu/wex/copyright\_and\_patent\_power.
[3] “An International Guide to Patent Case Management for Judges.” Accessed April 23, 2026. https://www.wipo.int/patent-judicial-guide/.
[4] Collier, Roger. “Drug Patents: The Evergreening Problem.” CMAJ : Canadian Medical Association Journal 185, no. 9 (2013): E385–86. https://doi.org/10.1503/cmaj.109-4466.
[5] “Patent Essentials.” Text. Accessed April 23, 2026. https://www.uspto.gov/patents/basics/essentials.
[6] Tu, S. Sean. “The Long CON: An Empirical Analysis of Pharmaceutical Patent Thickets.” University of Pittsburgh Law Review 86, no. 1 (2024). https://doi.org/10.5195/lawreview.2024.1049.
[7] Lau, Jesper, Florencio Zaragoza Doerwald, Paw Bloch, and Thomas Kruse Hansen. Acylated GLP-1 compounds. United States Patent US8536122B2, filed March 5, 2012, and issued September 17, 2013. https://patents.google.com/patent/US8536122B2/en?oq=8536122.
[8] Lau, Jesper, Paw Bloch, and Thomas Kruse Hansen. Acylated GLP-1 compounds. United States Patent US8129343B2, filed March 20, 2006, and issued March 6, 2012. https://patents.google.com/patent/US8129343B2/en?oq=8%2c129%2c343.
[9] Almost every molecular compound described by the ’122 patent is also covered under the ’343 patent. This is possible because the two patents are ostensibly different, with the ’122 patent being narrowly defined to cover a small number of commercially promising semaglutide compounds. In contrast, the ’343 patent covers a much broader section of molecular compounds, but the definitions overlap, ensuring that many compounds are effectively patented twice.
[10] U.S. Congress. Senate. Drug Price Competition and Patent Term Restoration Act of 1984. S. 2926. 98th Cong., Introduced in Senate August 9, 1984.
[11] Food, Drug, and Cosmetic Act, U.S. Code 21 (1938). https://uscode.house.gov/view.xhtml?req=%28title:21%20section:355.
[12] Ibid.
[13] Ibid.
[14] Ibid.
[15] United States of America Federal Trade Commission Washington, D.C. 20580. Accessed April 23, 2026. https://www.ftc.gov/system/files/ftc\_gov/pdf/novo-nordisk-ozempic-saxenda-victoza-\_4302024.pdf.
[16] LII / Legal Information Institute. “35 U.S. Code § 154 - Contents and Term of Patent; Provisional Rights.” Accessed April 23, 2026. https://www.law.cornell.edu/uscode/text/35/154; (Novo Nordisk has already attempted to abuse the Orange Book loophole explained in more detail later; however, the FTC issued a letter of intent to investigate a suspected 36 abuses, 34 of which were related to semaglutide.)
[17] Novo Nordisk GLP-1 sales surge: 7 things to know. Accessed April 23, 2026. https://www.beckershospitalreview.com/glp-1s/novo-nordisk-glp-1-sales-surge-7-things-to-know/.
[18] “Semaglutide Sales Forecast: Revenue Projections Through 2030 - Pharmacy Business Hub.” August 9, 2025. https://pharmabusinesshub.com/semaglutide-sales-forecast/.
[19] LLC, Glunova Biotech. “Glunova Biotech - Metabolic Health & Longevity Education.” Glunova Biotech. Accessed April 23, 2026. https://www.glunovabio.com.
[20] Schuhmacher, Alexander, Markus Hinder, Elazar Brief, Oliver Gassmann, and Dominik Hartl. “Benchmarking R&D Success Rates of Leading Pharmaceutical Companies: An Empirical Analysis of FDA Approvals (2006–2022).” Drug Discovery Today 30, no. 2 (February 2025): 104291. https://doi.org/10.1016/j.drudis.2025.104291.
[21] ASPE. “Costs of Drug Development and Research and Development Intensity in the US, 2000-2018.” June 28, 2024. http://aspe.hhs.gov/reports/drug-development-rd-intensity.
[22] “Novo Nordisk Gross Profit 2012-2025 | NVO.” Accessed April 23, 2026. https://www.macrotrends.net/stocks/charts/NVO/novo-nordisk/gross-profit; “The Top 20 Pharma Companies by 2025 Revenue | Fierce Pharma.” Top 20 Pharma Companies 2025 Revenue. Accessed April 23, 2026. https://www.fiercepharma.com/special-reports/top-20-pharma-companies-2025-revenue.
[23] Dose of reality: Big pharma’s patent abuse extending monopolies, keeping prices high on GLP-1s - CSRxP. Accessed April 23, 2026. https://www.csrxp.org/dose-of-reality-big-pharmas-patent-abuse-extending-monopolies-keeping-prices-high-on-glp-1s/.
[24] “Google Patents.” Accessed April 23, 2026. https://patents.google.com/?q=(semaglutide)\&assignee=Novo+Nordisk+A%2fS\&country=US\&status=GRANT.
[25] Novo Nordisk Inc. v. Mylan Pharmaceuticals Inc. (https://www.ded.uscourts.gov/sites/ded/files/opinions/23-101\_0.pdf July 22, 2025).
[26] U.S. Congress. Senate. Drug Price Competition and Patent Term Restoration Act of 1984. S. 2926. 98th Cong., Introduced in Senate August 9, 1984.
[27] Novo Nordisk Inc. v. Mylan Pharmaceuticals Inc. (https://www.ded.uscourts.gov/sites/ded/files/opinions/23-101\_0.pdf July 22, 2025).
[28] Ibid.
[29] Nielsen, Flemming S., and Per Sauerberg. Oral dosing of GLP-1 compounds. United States Patent US10278923B2, filed July 17, 2017, and issued May 7, 2019. https://patents.google.com/patent/US10278923B2/en?oq=10%2c278%2c923.
[30] Lau, Jesper, Florencio Zaragoza Dorwald, Henrik Stephensen, Paw Bloch, Thomas Kruse Hansen, and Kjeld Madsen. Acylated glp-1 compounds. Canada Patent CA2601784C, filed March 20, 2006, and issued December 24, 2013. https://patents.google.com/patent/CA2601784C/en?oq=CA+2%2c601%2c784.
[31] “Google Patents.” Accessed April 23, 2026. https://patents.google.com/?q=(CA+GLP-1)\&assignee=Novo+Nordisk+A%2fS\&country=CA.
[32] Canada, Health. “Government of Canada.” Canada.ca, January 9, 2025. https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/applications-submissions/guidance-documents/patented-medicines/notice-compliance-regulations.html.
[33] The Patent Act of 1970. Accessed April 23, 2026. https://ipindia.gov.in/pages/patents/chapter.
[34] Novo Nordisk As vs Dr. Reddys Laboratories Limited & Anr (https://indiankanoon.org/doc/39726850/ December 2, 2025).
[35] Ibid.
[36] Ibid.
[37] Statista Daily Data. “Infographic: U.S. Accounts for Nearly Half of the Global Pharma Market.” January 9, 2026. https://www.statista.com/chart/35653/largest-pharmaceutical-markets-by-sales.
[38] Federal Trade Commission. “FTC Issues Policy Statement on Brand Pharmaceutical Manufacturers’ Improper Listing of Patents in the Food and Drug Administration’s ‘Orange Book.’” September 14, 2023. https://www.ftc.gov/news-events/news/press-releases/2023/09/ftc-issues-policy-statement-brand-pharmaceutical-manufacturers-improper-listing-patents-food-drug.
[39] Ibid.
[40] Lammi, Glenn. “The Current Status of FTC’S Orange Book Listings Challenge: A Mixed Bag.” Washington Legal Foundation, August 5, 2024. https://www.wlf.org/2024/08/05/publishing/the-current-status-of-ftcs-orange-book-listings-challenge-a-mixed-bag/.
[41] United States of America Federal Trade Commission Washington, D.C. 20580. Accessed April 23, 2026. https://www.ftc.gov/system/files/ftc\_gov/pdf/novo-nordisk-ozempic-saxenda-victoza-\_4302024.pdf.
[42] U.S. Congress. House. An act to provide for reconciliation pursuant to title II of S. Con. Res. 14. H.R. 5376. 117th Cong., Introduced in Senate September 27, 2021.
[43] Ibid.
[44] U.S. Congress. House. A Bill to Promote the Progress of the Useful Arts (the Patent Act). H.R. 41. 1st Cong., Introduced in House March 10, 1790.
[45] U.S. Congress. Senate. An Act to promote the progress of useful arts, and to repeal all acts and parts of acts heretofore made for that purpose. S. 239. 24th Cong. Introduced in Senate April 28, 1836.
[46] U.S. Congress. House. An Act to revise, consolidate, and amend the Statutes relating to Patents and Copyrights. (Patent Act of 1870, Trade Mark Act of 1870, Copyright Act of 1870) H.R. 1714. 41st Cong., Introduced in House July 8, 1870.
[47] U.S. Congress. House. American Inventors Protection Act of 1999
H.R. 1907. 106th Cong., Introduced in House May 24, 1999.
[48] U.S. Constitution, art. 1, sec. 8, cl. 8.
[49] Keyhani, Salomeh, Steven Wang, Paul Hebert, Daniel Carpenter, and Gerard Anderson. “US Pharmaceutical Innovation in an International Context.” American Journal of Public Health 100, no. 6 (2010): 1075–80. https://doi.org/10.2105/AJPH.2009.178491.
[50] NCHS Data Brief no. 470 June 2023. Accessed April 23, 2026. https://www.cdc.gov/nchs/data/databriefs/db470.pdf.