The Real Evergreening Problem in Drug Patent Policy: I-MAK’s Inaccurate and Unreliable Drug Patent Claims

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Executive Summary

For well over 50 years, U.S. policymakers have debated the cost of healthcare. These debates have produced numerous laws and regulatory initiatives aimed at lowering healthcare prices for patients.^[1] In recent years, though, the debate has focused on drug patents due to claims that they cause higher prescription drug prices. Seven bills were introduced in the last two years in the 119th Congress that alter patent doctrines, eliminate patent rights, or sanction drug innovators under the antitrust laws—all for the stated goal of lowering drug prices.^[2]

Who created this link between drug patents and prescription drug prices? One of the principal sources is a policy organization called the Initiative for Medicines, Access, and Knowledge (I-MAK).^[3] Founded about 20 years ago, I-MAK’s mission is to convince policymakers that a “root cause of the high cost of medicines” is “unjust patent monopolies,” as it states on its website.^[4]

About a decade ago, I-MAK began releasing perennial brochures with splashy graphics and charts asserting eye-popping numbers of patents covering breakthrough, best-selling drugs. These massive numbers of patents, I-MAK claims, create “patent thickets” (obtaining numerous patents covering a single drug) and serve as “evergreening” tactics (artificially extending exclusive patent terms by stacking terms of follow-on patents). These nefarious tactics block generic drug companies from competing with “brand-name” drug companies. As a result, drug prices are kept high by these “unjust patent monopolies.” I-MAK’s brochures and its reported numbers of patents are a wellspring for these allegations, and the drug patent bills pending in Congress can be traced in some way or another back to I-MAK’s numbers of patents and allegations.^[5]

The problem is that I-MAK’s numbers don’t add up. In a policy memo published in 2022, I identified significant discrepancies between I-MAK’s numbers of patents it claims cover drugs in its brochures and the official, public listing of patents covering drugs approved by the Food and Drug Administration (FDA) in what is known as the “Orange Book.”^[6] That same year, Senator Thom Tillis requested that I-MAK explain its statistical methods and identify the specific patents represented by the aggregate numbers listed in its splashy charts and graphs. In its response two months later, I-MAK refused to do this. Senator Tillis also asked the U.S. Patent and Trademark Office (USPTO) and FDA to study I-MAK’s numbers of drug patents and its statistical methods of analysis. In 2024, the USPTO released this study, reviewing the patents covering several drugs in I-MAK’s brochures, finding I-MAK’s counting methodology to be deficient and unreliable, which I described in another policy memo that I published later that year.^[7]

Undeterred, I-MAK continues to release more brochures with more splashy graphics and large numbers of patents and years of exclusivity, accusing drug innovators of engaging in “patent thicket” and “evergreening” strategies to extend their “monopolies” to keep “prices high” for patients.^[8] With each additional brochure, I-MAK also updates its new “Drug Patent Book” with patent information on drugs it claims to have analyzed in support of its claims. I-MAK launched the Drug Patent Book in 2025. On its website, I-MAK says the goal of its “database” is to provide “better information, better decisions” to support “transparency and access to the information about the drug patents impacting Americans and their healthcare.”^[9]

This policy memo provides an updated review of the evidence that refutes I-MAK’s claims in its most recent brochures since the last policy memo I published in December 2024, which had similarly identified significant concerns about the reliability of I-MAK’s patent-counting methodology and the veracity of its assertions about the numbers of patents and exclusivity periods for drugs. Additionally, it details the first comprehensive analysis of the drugs in I-MAK’s Drug Patent Book in assessing I-MAK’s claims of widespread patent thicket and evergreening strategies that allegedly extend periods of exclusive protection from generic and biosimilar competition for innovative drugs. The memo reaches the same conclusions as prior studies by the USPTO and empirical scholars: I-MAK’s allegations are based on misleading data, and its conclusions are distorted by an unreliable method of patent counts that has been widely criticized for over three decades by economists and empirical researchers.^[10] I-MAK’s claims are infected with the same defective data and methodological failures previously critiqued by the USPTO, Hudson policy memos, and scholars.

In sum, if evergreening is real, it is occurring in the drug pricing policy debates, not in granted patents on new drugs.^[11] The real evergreening is I-MAK’s perennial brochures, which continually assert to policymakers in Washington, D.C. unreliable numbers of patents and inaccurate claims of “monopolies” by drug innovators. I-MAK’s 2025 and 2026 brochures and its self-styled Drug Patent Book continue this evergreening practice and policy advocacy.

A Brief History of I-MAK’s Discredited Patent Numbers and Patent Counting Method

I-MAK has been a principal advocacy organization leading the charge in accusing drug innovators of compiling massive numbers of patents for the purpose of extending the “duration of patent protection,”^[12] and thereby “blocking competition” from generic drugs.^[13] Patent lawyers, scholars, and the USPTO have repeatedly identified numerous inaccuracies, inconsistencies, and deficiencies in I-MAK’s publications and reported patent counts. Sometimes I-MAK responds to these critiques by quietly removing one of the criticized patent counts from the next version of its brochure; for example, Lyrica was removed in its brochures published after 2019.^[14] But its inaccurate numbers of patents and unreliable counting methodology continue unabated, despite these repeated critiques. To properly evaluate I-MAK’s repeated claims, it is necessary to establish the context of this evergreen strategy by I-MAK in ignoring critiques and continuing to publish inaccurate and unreliable claims about prescription drugs and their periods of exclusivity.^[15]

I-MAK first began regularly releasing brochures about a decade ago asserting that “patents cause high drug prices,” and from the get-go, there were concerns I-MAK was playing fast and loose with its alleged data and its legal claims. In its 2017 brochure, for example, I-MAK included in its “total patents” counts granted patents and patent applications, including even abandoned patent applications.^[16] In formal comments at the Joint PTO-FDA Public Listening Session on Collaboration Initiatives, Corey Salsberg, Vice President and Global Head of Intellectual Property Affairs for Novartis, explained that Novartis had expended significant time and resources to reverse engineer I-MAK’s claim in its 2017 brochure that one of his company’s drugs, Gleevec, is covered by “a total of 73 patents.”^[17] Mr. Salsberg explained that “the real number of issued U.S. patents on Gleevec was five, with another one to four possibly covering some of the ways of making it, but only if those methods were (optionally) used. . . . I-MAK appears to have reached its inflated figures by including 44 abandoned patent applications that never issued as patents, as well as a variety of patents that don’t cover our drug.”^[18]

I-MAK’s claims about “total patents” covering breakthrough drugs simply did not add up. No USPTO official would ever include pending patent applications, abandoned patent applications, and even patents that don’t cover a drug in claiming a count of “a total of 73 patents” covering this drug, as I-MAK asserted about Gleevec in its 2019 brochure on drug patents. No patent lawyer would make this claim in court. It is simply false as a matter of patent law.

Given these concerns—especially given how Congress and academics, and even witnesses appearing in hearings before Congress, rely on I-MAK’s numbers of patents—Senator Thom Tillis wrote to I-MAK in 2022 requesting “a detailed explanation of your methodology for calculating the number of patents on a drug product that could be replicable by other researchers.”^[19] At the same time, Senator Tillis made the same request of I-MAK to the USPTO and FDA to “conduct an independent assessment and study” in order “to ensure that policymaking in this critical area is based on accurate, reliable, and replicable facts and evidence.”^[20]

In a lengthy letter responding to Senator Tillis more than a month later, I-MAK founder and CEO Tahir Amin refused to answer Senator Tillis’s requests for disclosure of its specific data and counting methodology used in its 2018 and 2019 brochures.^[21] More than four years later, I-MAK still has not answered Senator Tillis’s request that I-MAK disclose its specific data on the specific patents and the statistical methodology that I-MAK used to produce the numbers of patents and alleged patent terms for the drugs that I-MAK specifically identified in its 2018 and 2019 brochures.^[22]

The same month that the Senator sent his letter to I-MAK, I published a policy memo identifying glaring inconsistencies between the official, public data in the FDA’s Orange Book listings for drug patents and I-MAK’s claims about the numbers of patents and patent terms for these same drugs in I-MAK’s 2018 and 2019 brochures. Pfizer’s drug, Lyrica, is one notorious example. In its 2018 brochure, I-MAK asserted that Pfizer had 68 patents covering Lyrica, but the FDA’s Orange Book identified only three original patents covering Lyrica.^[23] This is not a minor counting mistake; it is a difference in orders of magnitude.

Similarly, I-MAK asserted in its 2018 brochure that Pfizer would retain exclusive rights over Lyrica until 2038—a whopping 20 years after the publication of its 2018 brochure and more than 10 years after the expiration of the patents listed in the FDA’s Orange Book for Lyrica. But the main patent on the active ingredient in Lyrica expired that same year (2018), and the FDA approved nine generic versions of Lyrica in 2019 to compete with Lyrica in the healthcare market.^[24] Again, a 20-year discrepancy is not a minor counting mistake. Tellingly, I-MAK quietly removed Lyrica from its lists of drugs that it alleges are protected by patent thickets and evergreening tactics in its subsequent brochures.^[25]

Lastly, the USPTO responded to Senator Tillis’s request in 2022 that the USPTO and FDA undertake an independent review of I-MAK’s claims in I-MAK’s 2018 and 2019 brochures by releasing in June 2024 its Drug Patent and Exclusivity Study.^[26] The USPTO neither replicated nor confirmed I-MAK’s claims concerning the numbers of patents on specific drugs like Lyrica listed in its 2018 and 2019 brochures. It also found significant methodological flaws in I-MAK’s practice of simply counting all patents that may be related to or cover one aspect of an invention in a drug product approved by the FDA, and then simply stacking these patent terms sequentially.

The USPTO found no correlation between the number of patents covering a drug approved by the FDA and the length of this drug’s actual market exclusivity. The USPTO observed that “simply quantifying raw numbers of patents and exclusivities is an imprecise way to measure the intellectual property landscape of a drug product because not every patent or exclusivity has the same scope. For example, one patent could contain different sets of claims directed to: (1) a pharmaceutical product, (2) a method of using the product, and (3) a process for manufacturing the product.”^[27] The USPTO pointedly observed that “a higher number of patents may not necessarily delay a generic launch,” such as in the case of Revlimid (one of the drugs in I-MAK’s brochures).^[28] In sum, simply counting patents and adding up successive patent terms without considering the actual inventions covered by the patents produces unreliable results, at best, or outright inaccurate results, at worst. I-MAK’s false claims about Lyrica exemplify this fact.

The USPTO was not saying anything new in its 2024 analysis of I-MAK’s assertions about total drug patents and market exclusivity periods. Given that each patent can only issue for a new and useful invention, simple patent counting has long been recognized as a deeply flawed method for studying patents, whether in assessing exclusivities, patent term lengths, or even in assessing the total value of a portfolio of patents owned by a corporation. Empirical researchers have known for several decades that simple patent counts of the sort done by I-MAK in all of its brochures up through its most recent brochure in 2025 are unreliable and inaccurate.^[29]

I-MAK’s Discredited Patent Counts and Exclusivity Periods for GLP-1 Drugs

This pattern of unreliable data and inaccurate claims about alleged patent thickets and evergreening tactics continued in early 2025 when I-MAK released another brochure accusing the innovators who created the GLP-1 weight loss drugs of improperly extending their patent protections for many years to keep prices high.^[30] Two former USPTO and FDA attorneys analyzed this new I-MAK brochure on GLP-1 drugs and found that I-MAK’s overly broad search terms created a distorted picture of the patent landscape on these life-saving inventions. As with all of I-MAK’s prior brochures, I-MAK simply counted patents regardless of what inventions these patents in fact covered and even “neglected to investigate whether the patents it identified were in force when the respective [drug] products were approved [by the FDA].”^[31]

I-MAK in fact repeats the same error in its 2025 brochure on GLP-1 drugs that it committed in its 2018 brochure when it falsely accused Pfizer of improperly extending its “monopoly” on Lyrica until 2038.^[32] In its new brochure on GLP-1 drugs, I-MAK now accuses Novo Nordisk of creating a “considerable patent thicket” for its GLP-1 weight-loss medicines containing semaglutide.^[33] I-MAK claims that Novo Nordisk has filed “91 patents” for these medicines that legally lock-in “patent protections until 2042.”^[34] I-MAK says outright that this is “an additional ten years beyond the main compound patent for semaglutide” and that this patent thicket was created for the purpose of “extending Novo Nordisk’s market monopoly.”^[35]

Just as in 2018, I-MAK’s perennial rhetoric in 2025 of a “market monopoly” lasting for many decades that “add[s] barriers of entry for generic competitors” does not match the facts. First, the attorneys who analyzed I-MAK’s total patent count found I-MAK included any patents or patent applications that I-MAK considered to be “related to” semaglutide. They found that I-MAK used this loosey-goosey “related to” standard to “mistakenly assert that the earliest patent applications ‘related to’ semaglutide were filed in 1993.”^[36] I-MAK thus argued that there is a whopping 49 years of an exclusive “market monopoly” for Novo Nordisk’s semaglutide medicines. Yet, as the attorneys explained, the 1993 “related to” patent counted by I-MAK as the baseline for this 49-year exclusivity period neither covered semaglutide nor was it still in force when the FDA first approved the use of this medicine in 2017 for the treatment of diabetes.^[37]

I-MAK’s evergreening of its discredited patent counting method leads it to repeat the same errors in its earlier brochures: it asserts the existence of patent thickets and eye-popping half-century-long exclusive “monopolies” on GLP-1 drugs. When patent lawyers and empirical researchers investigate both the numbers and counting method in I-MAK’s brochures, they find substantial methodological flaws and significant errors. As one law professor observes in a recent empirical study of the significant impact that I-MAK’s 2018 brochure has had in its extensive citation in academic scholarship and in policymaking, “the I-MAK case study shows how narrative amplification can propagate empirical claims that do not survive independent scrutiny.”^[38] But I-MAK keeps perennially releasing its brochures, and its claims continue to be cited by academics and parroted to policymakers in regulatory agencies and Congress in prompting enforcement actions and new legislation, such as the seven bills in the 119th Congress alone.^[39]

I-MAK’s Inaccurate and Unreliable Claims About Patents on Biologics

Recently, there has been an intensifying policy debate about the cost of biologics and patents. Biologics are complex medicines derived from living cells and made through highly complex manufacturing processes. These medicines treat a wide range of debilitating medical conditions, including cancer, autoimmune disorders, rare diseases, and much more. Unsurprisingly, I-MAK has weighed in on this debate, asserting again that large numbers of patents and lengthy exclusive patent terms for biologics prevent competition from biosimilars (the biologic equivalent of a generic drug). Thus, it is necessary to review rigorous assessments of I-MAK’s claims about biologics in the scholarly literature.

Professor Erika Lietzan recently published research that identifies (again) significant concerns about the inaccuracy in I-MAK’s claims regarding biologics and biosimilar competition.^[40] Professor Lietzan analyzed 11 biologics that I-MAK asserts are blocking biosimilar competition with thickets, evergreening, or both tactics.^[41] The patents counted by I-MAK in support of its claims—and I-MAK’s own admission that it is in fact simply counting patents—are available in I-MAK’s Drug Patent Book.^[42] Her new research confirms (again) significant methodological flaws and unreliable or outright inaccurate claims by I-MAK about biologics.

As a preliminary matter, I-MAK uses the same simplistic method of merely counting patents for biologics that it has used for small molecule drugs over the years, as well as in its 2025 report on GLP-1 drugs. Even when a simple counting methodology is performed correctly, it has long been discredited by empirical researchers for producing inaccurate results about a patent’s legal effects or economic value, as the USPTO described at length in its Drug Patents and Exclusivity Study.^[43] If this counting method is done sloppily or if patents and patent applications that should not be included are included in these counts, as described above in the USPTO’s and other reviews of I-MAK’s brochures, then this counting method results in clearly erroneous results. These serious errors occurred in I-MAK’s claim about the total patents covering Gleevec in its 2017 brochure, in its claim about the total years of market exclusivity for Lyrica in its 2018 brochure, and in its claim about the total years of patent protection for the semaglutide medicines in its April 2025 brochure on GLP-1 drugs. If I-MAK continues to insist on evergreening the same discredited methodology, there is no reason to think that its claims about biologics will not suffer from the same flaws. For several reasons, these concerns have been borne out.

First, I-MAK is making claims about biologics patents blocking biosimilar competition that are impossible to infer from some of the patents. The reason is simple: biologics are a relatively new healthcare innovation, and Congress did not create a regulatory approval process for biosimilars until the Biologics Price Competition and Innovation Act of 2009 (BPCIA).^[44] The biosimilar approval process created in the BPCIA did not go into effect until 2010, and the FDA still took several more years to establish the processes, rules, and data requirements for biosimilar applications.^[45] As a result, the first biosimilar, Zarxio by Sandoz, did not even launch under the BPCIA regime until 2015.^[46]

Yet I-MAK was asserting just three years later in its 2018 brochure—and again in its 2019 brochure the next year—that patents on biologics were blocking biosimilar competition.

For some of the 11 biologics analyzed by Professor Lietzan, I-MAK’s claims of blocked competition are simply false as a matter of basic legal fact. Under the BPCIA, the FDA may not approve a biosimilar until after 12 years of data exclusivity, which starts on the date that an innovator’s biologic approved by the FDA is first licensed as a medicine that can be prescribed to patients.^[47] Professor Lietzan found that two of the biologics in I-MAK’s brochures were still within this 12-year statutory period of data exclusivity.^[48] There was no biosimilar competition for these biologics, not because of patents granted under the Patent Act, but because of the FDA regulatory protections provided to innovators of biologics by Congress under the BPCIA.

Furthermore, Professor Lietzan found that another eight biologics in I-MAK’s brochures already had biosimilar competition in the healthcare market.^[49] This confirms that I-MAK indeed repeated eight times over its glaring error in 2018 about the alleged patent “monopoly” on Lyrica until 2038, with the FDA approving generic competition for Lyrica the very next year after I-MAK’s claim (2019).^[50] In fact, I-MAK’s errors in asserting whopping time periods of exclusive monopoly protection for biologics were very similar to its Lyrica faux pas. For example, I-MAK asserted in its 2018 brochure that biologic Rituxan had a total of 47 years of exclusivity that was “blocking competition” by a biosimilar, but an FDA-approved biosimilar entered the healthcare market to compete with Rituxan the very next year (2019).^[51] As with other drugs that had similarly flagrant false claims, I-MAK quietly removed Rituxan from its subsequent brochures.^[52]

I-MAK’s Drug Patent Book – The Same Old Wine in a New Bottle

For almost a decade, I-MAK’s patent counting methods, its assertions of total numbers of patents covering small-molecule drugs and biologics, and its allegations of many decades of “exclusive” protections for medicines by patents have been consistently and repeatedly critiqued by scholars and governmental officials. Given this history, a new assessment of I-MAK’s latest effort in its online Drug Patent Book is warranted to confirm if it is repeating (again) the same errors previously identified in its past brochures perennially released in Washington, D.C.

There are currently 32 distinct medicines, including both small-molecule drugs and biologics, listed in I-MAK’s Drug Patent Book. Similar to past analyses of I-MAK’s recurring assertions about blocked generic or biosimilar competition from patent thicket and evergreening tactics, one can ask the following questions about these drugs and biologics:^[53]

The following analyses in answering these questions focus on the original approved dosage form or formulations of medicines, given they are the most relevant to assessing these questions.^[54] This narrows the relevant medicine products currently listed on I-MAK’s Drug Patent Book for this analysis to 29 medicine products.

As a preliminary matter, the most recent empirical study published in 2021 has confirmed an average market exclusivity period of 13–14 years for brand-name drugs before generic competition begins in the healthcare market.^[55] This finding in 2021 by healthcare economists is consistent with numerous rigorous studies of average market exclusivity periods for brand-name drugs that have been published for over a decade by economists and empirical scholars using different methods of analyses.^[56] According to scholarly research standards, such consistent empirical findings over many years by different scholars using different methodologies are indicative of a robust and strong empirical conclusion. It bears emphasizing that 13–14 years of market exclusivity for a drug innovator is well under the 20-year patent term secured to all innovators by the Patent Act.^[57] There is no “extension” of the patent term.

In answer to Question (1), 19 of the 29 drugs or biologics currently listed in I-MAK’s Drug Patent Book were not approved by the FDA long enough ago to expect competition, given either the average 13–14 years of exclusivity for new drugs or the 12-year data exclusivity period for biologics under the BPCIA.^[58] For example, Imbruvica by AbbVie is in I-MAK’s Drug Patent Book, but it was approved by the FDA on November 13, 2013, and thus one would not expect generic entry until roughly November 2028, approximately 14 years from the date of FDA approval of Imbruvica. Once again, I-MAK asserts evergreening tactics that wrongly extend a “monopoly” for 29 drugs and biologics, but this is false for more than one-half of the medicines in I-MAK’s Drug Patent Book because they either are drugs that are still within the average period of market exclusivity or are biologics that are legally barred from biosimilar competition due to data exclusivity.

In answer to Question (2), nine of the 29 drugs or biologics currently listed in I-MAK’s Drug Patent Book as the alleged subject of evergreening extensions of a “monopoly” that result in higher prices for patients already have generic or biosimilar competition in the healthcare market. For example, the biologic Eylea by Regeneron was initially approved by the FDA on November 18, 2011, and an FDA-approved biosimilar by Amgen entered the healthcare market on May 20, 2024. This means that Regeneron had an exclusivity period for Eylea of only 12.5 years. Yet Eylea appears in I-MAK’s Drug Patent Book and is apparently associated with numerous patents enabling Regeneron to employ evergreening tactics that extend market exclusivity far into the future. The error-prone method of I-MAK’s simple counting of patents without regard to what specific inventions these patents cover within the distinct “drug product” approved by the FDA continues to produce false claims by I-MAK, just as it did in its past brochures reaching back to 2018.

Lastly, in answer to Question (3), the nine FDA-approved products that have generic or biosimilar competition in the market, one can calculate the average time to generic or biosimilar entry using one of three different methods:^[59]

Despite the differences between these three methods of calculating average market exclusivity for biologics, the results of all three methods are strikingly consistent in producing an average market exclusivity period between 13.69 and 14.55 years for drug and biologic innovators. The average period of market exclusivity for drugs and biologics produced by these three methods (13.69–14.55 years) is also notably consistent with the results of past empirical studies of market exclusivity periods for drugs, including the most recent 2021 study that found approximately 13–14 years of market exclusivity for drug innovators.^[61] When this time period of exclusivity is measured against the legal period of exclusivity secured to innovators under the Patent Act for all patents, it is almost one-third less than the 20-year patent term under U.S. law.^[62]

Once again, I-MAK’s latest alleged numbers of patents and decades of “monopoly” pricing in its Drug Patent Book do not withstand empirical analysis based on publicly available data. Its unreliable and simplistic method of counting up patents produces inaccurate or outright false results. This has proven true for I-MAK’s many brochures over the years, and it remains true for its Drug Patent Book today.

Conclusion

If I-MAK’s evergreening of its inaccurate patent numbers and unreliable counting methods occurred only in academic discussions in the ivory tower, its claims could be safely ignored. But they do not. I-MAK’s unreliable and inaccurate numbers and its “monopoly” rhetoric are actively pushed into the drug pricing policy debates in Washington, D.C., promoting real-world legislation and regulatory actions that seek to eliminate patent rights on new drugs and biologics, impose new regulatory burdens on the biopharmaceutical sector, and even sanction innovators.

The U.S. continues to be a leader in new healthcare innovations; almost two-thirds of all new medicines are invented in the U.S. This global leadership, and the innumerable lives that have been saved by these healthcare inventions, are threatened when the drug innovation ecosystem is undone by legislation or regulatory actions that are based on policy-based evidence-making.

Endnotes

1. See, e.g., Inflation Reduction Act of 2022, Pub. L. No. 117-169, §§ 11001–11004, 136 Stat. 1818, 1833–64 (authorizing Centers for Medicare & Medicaid Services to “negotiate” prices of drugs purchased by the government). Patient Protection and Affordable Care Act, Pub. L. No. 111-148, 124 Stat. 119 (2010) (creating program known as ObamaCare); Medicare Prescription Drug, Improvement, and Modernization Act of 2003, Pub. L. No. 108-173, 117 Stat. 2066 (2003) (adding outpatient prescription drugs to Medicare program); Social Security Amendments of 1965, Pub. L. No. 89-97, § 102, 79 Stat. 286, 291 (1965) (creating Medicare program); Social Security Amendments of 1965, Pub. L. No. 89-97, § 121, 79 Stat. 286, 343 (creating Medicaid program). ↑
2. See Medication Affordability and Patent Integrity Act, S. 2658, 119th Cong. (Aug. 1, 2025); Eliminating Thickets to Increase Competition Act (ETHIC Act), S. 2276 (July 15, 2025); Preserve Access to Affordable Generics and Biosimilars Act, S. 1096 (Mar. 25, 2025); Interagency Patent Coordination and Improvement Act of 2025, S. 1097 (Mar. 24, 2025); Drug Competition Enhancement Act, S. 1040 (Mar. 13, 2025); Affordable Prescriptions for Patients Act, S. 1041 (Mar. 13, 2025); Stopping Pharma’s Ripoffs and Drug Savings For All Act, H.R. 890 (Jan. 31, 2025). ↑
3. See David S. Olson, Narrative Amplification in Drug Patent Scholarship, American U. L. Rev. (forthcoming 2027), https://papers.ssrn.com/abstract=6951618 (identifying I-MAK as one of the leading sources of the “patent-causal” argument linking patents and drug prices). ↑
4. I-MAK, Drug Pricing Crisis, https://www.i-mak.org/health-equity/#pricing (accessed Sep. 1, 2025) ↑
5. See, e.g., Olson, supra note 3, at 32-33 & 49 (identifying I-MAK’s 2018 brochure, Overpatented, Overpriced: How Excessive Pharmaceutical Patenting is Extending Monopolies and Driving Up Drug Prices, as a top-cited source in at least 97 law journal articles for causal claim that patents drive up drug prices). ↑
6. See Adam Mossoff, Unreliable Data Have Infected the Policy Debates Over Drug Patents (Hudson Institute, Jan. 19, 2022), https://www.hudson.org/technology/unreliable-data-have-infected-the-pol…. ↑
7. See Adam Mossoff, USPTO Confirms Unreliable Patent Numbers by I-MAK in Drug Pricing Debate (Hudson Institute, Dec. 10, 2024), https://www.hudson.org/drug-policy/uspto-confirms-unreliable-patent-num…. The USPTO’s report, Drug Patent and Exclusivity Study (2024), is available here: https://www.uspto.gov/sites/default/files/documents/USPTO_Drug_Patent_a…. ↑
8. See, e.g., I-MAK, The Monopoly Extension Menu (April 2026), https://reports.i-mak.org/monopoly-extension-menu/; I-MAK, The Heavy Price of GLP-1 Drugs: How Financialization Drives Pharmaceutical Patent Abuse and Health Inequities for GLP-1 Therapies, https://www.i-mak.org/wp-content/uploads/2025/04/The-Heavy-Price-of-GLP…. ↑
9. https://drugpatentbook.i-mak.org/ (last visited Oct. 15, 2026). ↑
10. See, e.g., Jean Lanjouw, Ariel Pakes & Jonathan Putnam, How to Count Patents and Value Intellectual Property: The Uses of Patent Renewal and Application Data, 46 J. Indus. Econ. 405, 413 (1998) (“[T]here is little doubt that the variability in patent value significantly reduces the efficacy of patent counts as a measure of invention.”). ↑
11. The term “drug” is legally ambiguous, and critics of drug patents like I-MAK and others exploit this ambiguity in their inaccurate and unreliable claims about the numbers of patents and terms of market exclusivity for drugs. See Erika Lietzan, Evergreening’s Empirical Chasm, in Bringing Medicines to Life: How Intellectual Property Enables Innovation in the Life Sciences 16 (eds. Jonathan M. Barnett and Bowman Heiden, Cambridge University Press 2026) (forthcoming), https://dx.doi.org/10.2139/ssrn.5404960 (“[T]hose who allege ‘evergreening’ write and speak loosely about patents and exclusivities for ‘drugs’—using an ambiguous term (‘drug’), which elides practical and legal distinctions between brand names, active ingredients, approved new drug applications, and specific finished products. These are distinct things, with different legal relevance.”). Still, the legal terms of art are technical and obscure even for lawyers who don’t work in patent law, such as the “drug products” approved by the FDA versus the “inventions” secured by patents. Id. at 16-18. Thus, this policy brief will continue to use “drug” to make it more accessible to people who are not specialists in patent law and FDA regulatory policy. ↑
12. See I-MAK, America’s Bestselling Drugs of 2019 (2020). ↑
13. See I-MAK, Overpatented, Overpriced: How Excessive Pharmaceutical Patenting is Extending Monopolies and Driving Up Drug Prices (2018). ↑
14. See Lietzan, supra note 11, at 23 (observing that “I-MAK quietly dropped Lyrica from its subsequent reports” falsely claiming in 2018 that there would not be any generic competition for 20 more years when a generic version of Lyrica was approved by the FDA the year after I-MAK released its report in 2018). ↑
15. There’s also a detailed historical account in my 2024 policy brief, USPTO Confirms Unreliable Patent Numbers by I-MAK in Drug Pricing Debate, supra note 7, at 2-4, and this section adds new data about this history. ↑
16. See I-MAK, America’s Overspend: How the Pharmaceutical Patent Problem is Fueling High Drug Prices (2017). ↑
17. See Statement of Corey Salsberg, Vice President and Global Head Intellectual Property Affairs for Novartis, Listening Session on Joint USPTO-FDA Collaboration Initiatives (Jan. 19, 2023), at 6, https://www.regulations.gov/comment/PTO-P-2022-0037-0017. ↑
18. Id. ↑
19. See Letter from Senator Thom Tillis to Tahir Amin (Jan. 31, 2022), https://s3.amazonaws.com/media.hudson.org/1.31.2022-%20LTR%20from%20Sen…. ↑
20. Letter from Senator Thom Tillis to Robert Califf, FDA Commissioner, and Drew Hirschfeld, USPTO Commissioner for Patents (Apr. 1, 2022), https://ipwatchdog.com/wp-content/uploads/2022/04/4.1.2022-TT-Ltr-to-US… [hereafter, “Tillis Letter to Califf & Hirschfeld”]. ↑
21. See Letter from Tamir Amin to Senator Thom Tillis (Mar. 9, 2022), https://ipwatchdog.com/wp-content/uploads/2022/03/Letter-to-Senator-Til…. ↑
22. In 2022, I-MAK published on its website a listing of patents, and it offered brief and highly generalized statements about its methods and data, such as that it “calculates” the “expiry date of a patent” by taking “information provided in Google Patents.” See https://drugpatentbook.i-mak.org/ (last visited August 30, 2026). This self-styled “I-MAK Drug Patent Book” still does not respond to Senator Tillis’s request in his 2022 letter that I-MAK disclose the specific data and detail its counting methodology that I-MAK used to reach the patent numbers published in its brochures in 2018 and 2019. ↑
23. Mossoff, supra note 6, at 3 (the FDA listed 4 total patents, but the fourth patent was only a “reissue” patent). ↑
24. Id. ↑
25. See supra note 14, and accompanying text. ↑
26. Drug Patent and Exclusivity Study, U.S. Patent and Trademark Office (June 2024), https://www.uspto.gov/sites/default/files/documents/USPTO_Drug_Patent_a…. ↑
27. Id. at 57. ↑
28. Id. at 59. ↑
29. See 5G Technological Leadership 2 (Hudson Institute, Dec. 4, 2020), https://www.hudson.org/technology/5-g-technological-leadership (critiquing simple patent counts in the high-tech sector given that “numerous empirical studies have shown that the value of patents varies enormously”). ↑
30. See How Financialization Drives Pharmaceutical Patent Abuse and Health Inequities for GLP-1 Therapies (April 2025), https://www.i-mak.org/glp-1/. ↑
31. Mary Till & Rachael Dippold, Counting Patents, Not Progress: Another Misdiagnosis by I-MAK, IPWatchdog (October 2025), https://ipwatchdog.com/2025/10/21/counting-patents-not-progress-misdiag…. ↑
32. As explained in the prior section, generic competition for Lyrica began in 2019, the year after I-MAK made this accusation in its 2018 brochure. ↑
33. How Financialization Drives Pharmaceutical Patent Abuse and Health Inequities for GLP-1 Therapies, supra note 30, at 11. ↑
34. Id. at 11. ↑
35. Id. at 11. ↑
36. Till & Dippold, supra note 36. ↑
37. See id. See Letter from Mary T. Thanh Hai, Dep. Dir., Off. of Drug Evaluation II, Off. of New Drugs, Ctr. for Drug Evaluation & Rsch., U.S. Food & Drug Administration, to Stephanie DeChiaro, Dir., Regul. Affs., Novo Nordisk Inc. (Dec. 5, 2017) (approving NDA 209637, Ozempic (semaglutide) injection), https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2017/209637s00…. ↑
38. Olson, supra note 3, at 58. In one carefully detailed trail of evidence, Professor Olson identifies the reliance and amplification of I-MAK’s patent thicket and evergreening claims as “I-MAK’s figures [in its 2018 brochure] traveled from an advocacy report through an advocacy organization’s blog post into a law review, losing every inferential constraint along the way.” Id. at 42. ↑
39. See supra note 2, and accompanying text. ↑
40. See Lietzan, supra note 11. ↑
41. Id. at 26. ↑
42. See supra note 9, and accompanying text. ↑
43. See supra notes 26-28, and accompanying text (describing the findings of the USPTO concerning the methodological deficiencies in simple patent counts of the sort used by I-MAK). ↑
44. Pub. L. No. 111-148, 124 Stat. 119 (2010). ↑
45. Lietzan, supra note 11, at 25. ↑
46. See Sandoz Inc. v. Amgen Inc., 582 U.S. 1, 13-14 (2017) (describing the Sandoz’s application to the FDA and the FDA’s subsequent approval for Zarxio). Zarxio, a biosimilar for Amgen’s Neupogen, treats low-white-blood cell conditions arising from chemotherapy, bone marrow transplants, and other conditions. ↑
47. See Biologics Price Competition and Innovation Act of 2009, Pub. L. No. 111-148, § 7002(a)(2), 124 Stat. 119, 804 (2010) (codified as amended at 42 U.S.C. § 262(k)(7)(A)). ↑
48. See Lietzan, supra note 11, at 27. These are Trulicity (dulaglutide) and Keytruda (pembrolizumab). ↑
49. See id. The biologics are Humira (adalimumab), Rituxan (rituximab), Herceptin (trastuzumab), Remicade (infliximab), Avastin (bevacizumab), Eylea (aflibercept), Lantus (insulin glargine), and Stelara (Ustekinumab). ↑
50. See supra note 23-25, and accompanying text. ↑
51. Lietzan, supra note 11, at 30. ↑
52. Id. Professor Lietzan reports that I-MAK quietly removed a total of five biologics from its brochures after their initial inclusion in the 2018 brochure. ↑
53. Analysis of the drugs and biologics listed in I-MAK’s Drug Patent Book, along with the methodologies for calculating average periods of market exclusivity for the drugs and biologics before competition from a generic or biosimilar, are compiled in an Excel spreadsheet file that is available for review upon request. Please email Adam Mossoff at the Hudson Institute to request a copy. ↑
54. Patents on later dosage forms and formulations (e.g., extended-release forms, subsequent fixed dose combination products) do not prevent FDA approval of generics or biosimilars to compete against the original approved dosage form or formulation. ↑
55. See Henry Grabowski, Genia Long, Richard Mortimer, & Mehmet Bilginsoy, Continuing Trends in U.S. Brand-Name and Generic Drug Competition, Journal of Medical Economics (2021), https://doi.org/10.1080/13696998.2021.1952795. ↑
56. These past studies each found an average time period of market exclusivity for an FDA-approved drug to be approximately 11-14 years before generic entry. See Mossoff, supra note 7, at 6-7 (summarizing six independent studies respectively finding approximately 11-14 years of market exclusivity for drugs). ↑
57. See 35 U.S.C. § 154(a)(2) (setting forth 20-year patent term). ↑
58. Only one drug in I-MAK’s Patent Book has no generic or biosimilar competition despite having been on the market for longer than the BPCIA data exclusivity period of 12 years or the average period of market exclusivity of approximately 13 years for biologics and generics. This outlier is Enbrel. As with all statistical outliers, there is a perfectly sensible explanation for what happened with Enbrel that Professor Lietzan succinctly describes in her recent book chapter. See Lietzan, supra note 11, at 30. ↑
59. These three methodologies for calculating average periods of market exclusivity for drug innovators before generic or biosimilar competition are in an Excel spreadsheet available ↑
60. See Lietzan, supra note 11. ↑
61. See supra notes 51-52, and accompanying text. ↑
62. See 35 U.S.C. § 154(a)(2) (setting forth 20-year patent term). ↑