On March 13, 2025, the U.S. Court of Appeals for the Federal Circuit affirmed a five-year patent term extension (“PTE”) for Merck’s sugammadex patent, holding that the district court had correctly calculated PTE based on the issue date of the original patent rather than the issue date of the reissued patent.[1]

Background

The case originated as a series of Hatch-Waxman litigations related to Merck’s Bridion®, a drug with the active ingredient sugammadex which is administered as an intravenous injection to reverse neuromuscular blockade, a form of paralysis induced by rocuronium bromide and vecuronium bromide in certain types of surgery.[2]

Merck originally obtained U.S. Patent No. 6,670,340 (“the ’340 patent”), which is directed to a class of 6-mercapto-cyclodextrin derivatives and issued on December 30, 2003, and applied to the Food and Drug Administration (“FDA”) for approval of a species within that class, sugammadex, shortly after on April 13, 2004.[3] Years later, while regulatory review was ongoing, Merck filed a reissue application for the ’340 patent that included both the original claims and narrower claims specifically directed to sugammadex, which was granted and issued as U.S. Patent No. RE44,733 (“the RE’733 patent”) on January 28, 2014.[4] The FDA approved sugammadex on December 15, 2015.

On February 10, 2016, Merck filed a PTE application for the RE’733 patent seeking PTE under 35 U.S.C. § 156 based on the original ’340 patent’s issue date (capped at five years under § 156(g)(6)(A)).[5] On February 4, 2020, the U.S. Patent and Trademark Office (“PTO”) granted a five-year PTE based on the ’340 patent’s issue date, extending the RE’733 patent’s expiration date from January 27, 2021, to January 27, 2026.[6]

In early 2020, Merck filed Hatch-Waxman lawsuits in the U.S. District Court for the District of New Jersey against several companies (collectively, “Aurobindo”) that had filed Abbreviated New Drug Applications (“ANDAs”) for generic versions of Bridion® and which had submitted Paragraph IV certifications as to the RE’733 patent.[7] The cases were consolidated.

At trial, Aurobindo argued that based on the plain text of § 156(c), which provides that the length of patent term extension is “the time equal to the regulatory review period… occur[ring] after the date the patent is issued,” the PTO should have calculated the RE’733 patent’s PTE based on the reissued patent’s issue date, rather than the original patent’s issue date.[8] Thus, the RE’733 patent was entitled not to a five-year PTE, but only to a 686-day PTE based on the period of regulatory review that had taken place after the RE’733 patent’s January 28, 2014 issue date, corresponding to an expiration date of December 14, 2022.[9]  Thus, Aurobindo sought to reduce the granted PTE by 1,140 days.

The district court rejected Aurobindo’s construction, and concluded that, when calculating PTE for a reissued patent, the PTO is statutorily required to base its calculation on the original patent’s issue date rather than the reissue patent’s issue date.[10] It thus held that the RE’733 patent was entitled to its full five-year PTE.[11]

Aurobindo appealed the decision. Notably, the PTO filed an amicus brief in support of Merck and took part in the oral argument on February 4, 2025.

The Federal Circuit’s Affirmance

On appeal, the Federal Circuit affirmed the district court’s holding, explaining that

[I]n the context of reissued patents, the reference to “the patent” in subsection 156(c) is to the original patent. Here, the ’340 patent included claims directed to the active ingredient for a drug product . . . . Under these circumstances, the RE’733 patent was entitled to a five-year PTE based on the ’340 patent’s issue date, since regulatory review effectively prevented the patent owner from enforcing the patent during that period.[12]

Central to the Federal Circuit’s decision was the statutory interpretation of 35 U.S.C. § 156(c). In this respect, the Federal Circuit found that “the language of subsection 156(c) standing alone is ambiguous.”[13] Looking to the statutory text and the broader context of the statute, the Federal Circuit explained that Congressional intent made clear the purpose of this section of the Hatch-Waxman Act: “to compensate the pharmaceutical companies for the effective truncation of their patent terms while waiting for regulatory approval of new drug applications.”[14] It emphasized that “[t]he statute contemplates a patentee receiving time lost in its patent term by reason of FDA delay, and the statute should be liberally interpreted to achieve this end,” and observed that Aurobindo’s construction of the statute, which would “den[y] Merck compensation for all but a small period of the delay,” was at odds with the purpose of the statute.[15]

The Federal Circuit thus concluded that “[a] reissued patent is entitled to PTE based on the original patent’s issue date where, as here, the original patent included the same claims directed to a drug product subject to FDA review.”[16] It added as a final note that the PTO’s revised Manual of Patent Examining Procedure, which instructs patent examiners to calculate the amount of PTE to which reissued patents are entitled based on the original patent’s issue date so long as both patents claimed or claim the approved product, “substantially tracks with our analysis as applied in this case.”[17]

Implications for PTE Based on Regulatory Review Period

In light of the Federal Circuit’s holding, the status quo with respect to how the USPTO calculates PTE based on the FDA’s regulatory review period remains unchanged. As the PTO suggested during oral argument, calculating PTE based on reissue date rather than the original patent’s issue date could lead to gamesmanship to maximize PTE by “either not filing the reissue or, at the [PTO], taking certain steps to delay your reissue application, until you get PTE on the original patent.” However, the affirmance avoids the need for such measures—patent owners can continue to file reissue patents without opening themselves up to the possibility of cutting off PTE (provided that both the reissued and original patents include the same claims directed to the approved drug product).

[1] Merck Sharp & Dohme B.V. v. Aurobindo Pharma USA, Inc., No. 23-2254 (Fed. Cir. Mar. 13, 2025) (available at https://www.cafc.uscourts.gov/opinions-orders/23-2254.OPINION.3-13-2025_2481365.pdf).

[2] Id. at 5-6.

[3] Id. at 5.

[4] Id. at 6.

[5] Id. at 6-7; 35 U.S.C. §§ 156(c), 156(g).

[6] Merck at 7.

[7] Id. at 7-8.

[8] Id. at 8.

[9] Id.

[10] Id. at 8-9.

[11] Id. at 9.

[12] Id. at 4.

[13] Id. at 10.

[14] Id. at 10-12.

[15] Id. at 13.

[16] Id. at 14-15.

[17] Id. at 16-17.

In our previous articles, we reported that the Federal Circuit affirmed the district court’s decision on December 20, 2024 ordering Teva Pharmaceuticals (“Teva”) to delist certain patents related to Teva’s ProAir® HFA metered-dose inhaler from the FDA’s Orange Book, and that the Federal Circuit subsequently stayed that delisting order on January 22, 2025 following a request from Teva for an en banc rehearing. On March 3, 2025, the U.S. Court of Appeals for the Federal Circuit denied Teva’s request for en banc rehearing.

With the denial of this petition, Teva is required to follow the district court’s delisting order and remove its inhaler patents — including U.S. Patent Nos. 8,132,712; 9,463,289; 9,808,587; 10,561,808; and 11,395,889 — from the Orange Book. It remains to be seen if Teva will now seek Supreme Court review.

The case is Teva Branded Pharmaceutical Products R&D Inc. v. Amneal Pharmaceuticals of New York LLC, case number 24-1936, in the United States Court of Appeals for the Federal Circuit. We will continue to monitor further developments in this case and provide insight and updates as they become available.

The U.S. stands at a crossroads in light of rising drug prices and it is unclear what the future will hold in answer to the rising drug costs. Biologic medicines have rapidly expanded available treatment options and accounted for approximately half of U.S. healthcare medicine spending in the past few years. While biosimilars have offered patients competing products at a fraction of the cost, the fledgling industry has been stymied by uncertainty.  Referred to as the “biosimilar void,” the future of the biosimilar market hangs in the balance, awaiting action to solve the unanswered questions circling the sustainability of biosimilar competition. In a February 2025 report, “Assessing the Biosimilar Void in the U.S.”1, the IQVIA Institute for Human Data Science outlines challenges faced by the biosimilars market as well as potential solutions to help promote healthy competition, reduce healthcare costs, and improve patient access.

Biosimilar Future Market Opportunities

Over the next decade (2025-2034), IQVIA reports that 118 biologics are subject to lose patent protection, thus presenting a $234 billion opportunity for biosimilar competition. Of these biologics, 22 are forecasted to exceed $2.5 billion in sales pre-expiry. The high-sales biologics facing expiry range from applications in immunology (11), oncology (6), neurology (2), hematology (1), diabetes (1), and cardiovascular diseases (1). Namely, the first PD-1 inhibitors (pembrolizumab, durvalumab, and nivolumab) are set to expire before 2034. However, with this loss of exclusivity, only 12 of these biologics have biosimilar versions in development. The author notes that this is not surprising when considering that only 14 out of 62 biologics that lost patent protection as of 2024 have biosimilar versions on the market. This gap in development leaves an opportunity to reduce costs and increase patient access to therapies, but that opportunity is hindered by difficult challenges.

Challenges to Biosimilar Development

The IQVIA report acknowledges that, to date, biosimilar development predominantly targets high-sales biologics, e.g., in oncology and immunology while leaving behind potential biosimilar competitors for lower lifetime sales medicines which make up almost $9 billion in branded sales. The remaining pre-expiry high-sales biologics without biosimilar development make up another $156 billion in potential earnings. The hesitation to tap into this untapped market largely stems from uncertainty in development costs (and subsequently the ability to recoup), regulatory hurdles, market unpredictability with shifting treatment paradigms, and market acceptance. Because biosimilar competitors mainly focus on biologics with greater than $1 billion in sales, the ability to recoup development costs with sales is likely the driving force behind the lack of biosimilar development. Even so, with such a vast number of high-sales biologics without biosimilar development, there are indications that sales potential is not the only factor stifling growth. 

Regulatory requirements create a tricky double bind beyond the typical burdens imparted by the approval process in cost and time. As of 2009, after the enactment of the Biologics Price Competition and Innovation Act (BPCIA), in order for biosimilars to demonstrate interchangeability it is required that there be “no clinically meaningful differences…in terms of safety, purity, and potency2” between the biologic and the biosimilar competitor, which tends to necessitate large and costly clinical trials. This creates additional hurdles during the regulatory process with the U.S. Food and Drug Administration (FDA). On the other hand, a lower interchangeability designation or non-interchangeability designation could feed into already present concerns and negative perceptions among patients and physicians about biosimilars as a whole. Market acceptance is already a barrier that biosimilar developers encounter even after the safety and efficacy has been proven, as biosimilar uptake post-market entry is modest at best3 . In a 2019 survey, 84% of physicians disapproved of nonmedical switching to biosimilars4 .

The report estimates that biosimilar development costs can reach upwards of $100 million. Thus, it is no surprise that developers are hesitant to commit resources in light of the uncertainties and challenges in this space. A clear example of this is complex biologics, e.g., antibody-drug conjugates, bispecific antibodies, and cell and gene therapies. Complex biologics introduce even steeper manufacturing and testing difficulties. As a result, there are currently no biosimilars in development targeting competition of the 16 complex biologics that will lose patent protection in the next decade. Further, competition for these complex biologics can come in other forms such as, for example, antibody-drug conjugates with the same antibody component but with different cytotoxic agents which can be categorized as a new product. As such, drug developers can market variants of branded biologics as a new product albeit at higher prices than biosimilar versions.

The authors mark payor behavior as also playing a significant role in biosimilar uptake. The payors, i.e., insurance companies, government health programs, Health Maintenance Organizations (HMOs), and Preferred Provider Organizations (PPOs), are responsible for negotiating drug reimbursement, which influences availability to patients. They are currently incentivized by higher rebates that tend to follow from originator biologic medicines which typically have higher listed prices than their biosimilar competitors. As in the case of pharmacy-dispensed medicines, which are controlled largely by pharmacy benefit managers (PBMs) who determine whether originator biologics or their biosimilar counterparts are listed on formularies, prices at the consumer level are highly variable. Similarly, the market size of biosimilars could be significantly impacted by the adoption of the Inflation Reduction Act (IRA). The IRA allows for Medicare to negotiate Maximum Fair Prices (MFPs) directly for high-spending drugs, which undermines one of the core benefits of biosimilars – the financially attractive price gap between biosimilars and their reference biologics. Of the 10 approved drugs currently listed for MFPs, 3 are biologics and none are biosimilars. Selectively narrowing the price gap between biosimilars and their reference biologics via price controls can be viewed as potentially dissuading developers further from investing.

Outlook

IQVIA estimates that avoiding the biosimilar void and achieving a fully competitive biosimilar market could bring to patients and the healthcare system approximately $189 billion in savings over the next decade. The author warns, however, that “[p]rogress toward a more sustainable biosimilar market requires re-assessment of current U.S. regulatory frameworks and market dynamics to facilitate access to biosimilars across all areas where biologic medicines exist and limit the magnitude of a biosimilar void.”

The impending expiration of patents for numerous biologics presents a significant opportunity for biosimilar manufacturers to enter the market. However, the complexity of the patent landscape necessitates a comprehensive strategy to navigate potential challenges effectively. A critical first step involves conducting thorough freedom-to-operate analyses to identify and assess existing patents that could impede biosimilar development. This process includes evaluating patent thickets—dense clusters of overlapping patents—that originator companies often establish to extend market exclusivity. By meticulously analyzing these thickets, biosimilar companies can develop strategies to challenge weak or non-essential patents, thereby facilitating earlier market entry. Additionally, engaging in the patent dance, a structured information exchange under the Biologics Price Competition and Innovation Act (BPCIA), allows for the early resolution of patent disputes, potentially expediting product launch. Furthermore, biosimilar companies should consider pursuing their own patent protections for unique manufacturing processes or formulations to strengthen their market position. By implementing these multifaceted patent strategies, biosimilar manufacturers can effectively capitalize on the upcoming wave of biologic patent expirations and enhance their competitiveness in the marketplace.

Disclaimer: The information contained in this posting does not, and is not intended to, constitute legal advice or express any opinion to be relied upon legally, for investment purposes or otherwise. If you would like to obtain legal advice relating to the subject matter addressed in this posting, please consult with us or your attorney. The information in this post is also based upon publicly available information, presents opinions, and does not represent in any way whatsoever the opinions or official positions of the entities or individuals referenced herein.

  1. https://www.iqvia.com/insights/the-iqvia-institute/reports-and-publications/reports/assessing-the-biosimilar-void-in-the-us ↩︎
  2. Implementation of the Biologics Price Competition and Innovation Act of 2009 | FDA ↩︎
  3. Gibofsky A, Evans C, Strand V. Provider and patient knowledge gaps on biosimilars: insights from surveys. Am J Manag Care. 2022 Nov;28(12 Suppl):S227-S233. Available from: https://www.ajmc.com/view/biosimilarssuppl-insightssurveys ↩︎
  4. Teeple A, Ellis LA, Huff L, et al. Physician attitudes about nonmedical switching to biosimilars: results from an online physician survey in the United States. Curr Med Res Opin. 2019;35(4):611-617. doi:10.1080/03007995.2019.1571296 ↩︎

Introduction

On January 6, 2025, the FDA released draft guidance on using artificial intelligence (AI) in regulatory decision-making for drugs and biological products.  The draft guidance – the first of its kind from the agency – aims to enhance the efficacy and accuracy of the drug approval process, ensuring that applications incorporating AI meet rigorous standards for safety and effectiveness. Public comments on the new guidance can be submitted through April 7, 2025.

The draft guidance provides recommendations for establishing and maintaining trust in AI systems used across the drug product lifecycle, focusing on safety, effectiveness, and quality.  In preparing the document, FDA considered input from the community, including feedback from “a number of interested parties including sponsors, manufacturers, technology developers and suppliers, and academics” and input provided at an FDA sponsored expert workshop convened by the Duke Margolis Institute for Health Policy in Dec. 2022. [1]

Key Highlights from the Guidance

While the FDA proposed guidance is procedural in nature, it is not without intrigue, as the abutment of artificial intelligence with biopharmaceuticals is not only a long time coming, but also a nexus with the potential to usher in landmark changes.  Thus, the FDA’s guidance – while tentative at this stage – will undoubtedly be closely scrutinized as AI-based data production is further integrated into the biopharma regulatory framework. 

The FDA’s guidance applies specifically to AI models used to produce data supporting regulatory decisions on drug safety, effectiveness, and quality.[2]  The guidance does not address the use of AI models (1) in drug discovery or (2) when used for operational efficiencies (e.g., internal workflows, resource allocation, drafting/writing a regulatory submission) that do not impact patient safety, drug quality, or the reliability of results from a nonclinical or clinical study.  Id.  Notably, the FDA encourages sponsors to engage with FDA early if they are uncertain about whether or not their use of AI is within the scope of this guidance.  Id.

A critical aspect of the guidance is its seven-step risk-based credibility assessment framework, designed to evaluate AI systems based on their context of use (COU) and the level of regulatory impact they have:

  1. Define the question of interest that will be addressed by the AI model;
  2. Define the COU for the AI model;
  3. Assess the AI model risk;
  4. Develop a plan to establish the credibility of AI model output within the COU;
  5. Execute the plan;
  6. Document the results of the credibility assessment plan and discuss deviations from the plan; and
  7. Determine the adequacy of the AI model for the COU.

Id. at pages 5-6.  In summary, the framework thus instructs (a) defining the question of interest and the context of use; (b) assessing AI model risk by considering the model’s influence and potential consequences of errors; (c) developing and executing a credibility plan tailored to the model’s risk level; and (d) documenting and evaluating results, allowing for iterative adjustments based on those results.

Lifecycle Management and Ongoing Challenges

A key focus of the guidance is AI model lifecycle maintenance, particularly addressing challenges like data drift — where an AI model’s performance degrades over time due to differences in new input data.  The FDA recommends continuous monitoring and updating of AI models to ensure they remain effective and reliable throughout their lifecycle.  The guidance also addresses broader AI-related concerns:

  • Dataset quality and integrity: AI models require high-quality, representative data to produce reliable outcomes.
  • Algorithmic bias: The FDA acknowledges the risk of bias in AI-generated results and stresses the importance of bias mitigation strategies.
  • Transparency and explainability: Regulatory decisions must be interpretable, necessitating AI models that provide clear, understandable justifications for their outputs.

Potential Questions and Issues to Address

While the draft guidance is a strong signal in the FDA’s efforts to integrate technological change in biopharmaceutical regulation, these efforts do not come without strain.  For example, it remains to be seen how stakeholders will consistently apply the guidance’s model risk matrix across diverse use cases, considering the relatively scant amount of guidance at present, as well as the numerous (and rapidly increasing) means by which AI can be leveraged in a scientific setting.  While the FDA guidance does not – and perhaps cannot – attempt to cover all implementations of AI, the speed at which technology processes, and at which the FDA responds, will need to be monitored closely, as several open questions remain:

  • Consistency in AI risk assessment: How will different stakeholders interpret and apply the AI risk matrix across diverse regulatory scenarios?
  • Regulation of self-evolving AI models: The FDA highlights concerns about AI systems that adapt over time, but the extent of post-approval oversight is still unclear.
  • Impact on smaller companies: Meeting the documentation and validation requirements could pose challenges for startups and smaller biopharma companies with limited regulatory experience.

Industry Engagement and Next Steps

The FDA is positioning this guidance as the beginning of an ongoing conversation, strongly encouraging sponsors to engage early to discuss AI model risk and credibility assessment plans. The agency outlined various engagement options for discussing AI in development programs, including INTERACT meetings for CBER and CDER products, as well as Pre-IND meetings.  Depending on the AI model’s intended use, sponsors and stakeholders can also explore other options, such as:

  • INTERACT meetings (for early-stage regulatory discussions)
  • Pre-IND meetings (for investigational new drug applications)
  • Digital Health Technologies Program (for AI and digital tool integration)
  • Complex Innovative Trial Design (CID) Program (for AI-driven trial methodologies)
  • Emerging Drug Safety Technology Program (EDSTP) (for post-market AI surveillance)

Id. at 17-20.

Conclusion

Publishing the guidance is the beginning, not the end, of the process, which FDA acknowledges will require a dialogue.  The FDA “strongly encourages” early engagement between sponsors and the agency to discuss the use of AI models in drug and biologic products, emphasizing the importance of expectation setting for credibility assessments and addressing potential challenges.

While the FDA will consider public feedback on whether its risk-based framework meets industry expectations (and whether current engagement opportunities are sufficient), this newly published guidance is a clear reflection of the FDA’s commitment to incorporating AI into regulatory processes while upholding safety and reliability standards.

[1] “Considerations for the Use of Artificial Intelligence to Support Regulatory Decision-Making for Drug and Biological Products.” Federal Register, vol. 90, no. 4, 7 Jan. 2025, pp. 851-855. U.S. Government Publishing Office, https://www.federalregister.gov/documents/2025/01/07/2024-31542/considerations-for-the-use-of-artificial-intelligence-to-support-regulatory-decision-making-for-drug.

[2] “Considerations for the Use of Artificial Intelligence to Support Regulatory Decision-Making for Drug and Biological Products.” U.S. Food and Drug Administration, Jan. 2025, https://www.fda.gov/media/184830/download at page 3.

On January 29, 2025, the Federal Circuit issued paired decisions addressing Samsung Bioepis’s (“SB”) and Formycon AG’s (“Formycon”) appeals of preliminary injunctions entered in ongoing aflibercept biosimilar litigations with Regeneron Pharmaceuticals, Inc. (“Regeneron”).[1] The Federal Circuit affirmed the district court’s exercise of personal jurisdiction over both defendants as well as the entries of preliminary injunctions against both companies’ aflibercept biosimilar products. With respect to personal jurisdiction, the Federal Circuit has taken a broad view of Acorda,[2] signaling that foreign companies that file an ANDA or aBLA in the U.S. can expect to be subject to personal jurisdiction in any given forum state unless they specifically carve out the forum state from their distribution networks for their drug products.

Formycon and SB are both foreign companies that filed aBLAs seeking FDA approval of aflibercept biosimilars in the United States. Both companies served on Regeneron a Notice of Commercial Marketing pursuant to 42 U.S.C. 262(l)(8)(A), which the Federal Circuit found “expressly communicated an intent to begin marketing of [the biosimilars] upon FDA approval.”[3] Both companies stated that they would not engage in any sales of their aflibercept biosimilar products, but instead have contracted (or will contract) with distributors who will make sales in the United States.[4]

In Acorda, the Federal Circuit addressed the question of whether a Hatch-Waxman defendant’s conduct satisfied the minimum contacts requirement for specific personal jurisdiction in the context of an infringement suit brought under 35 U.S.C. § 271(e)(2). The Court concluded that Mylan’s ANDA filings and its distribution channels were sufficient to establish personal jurisdiction in the forum state of Delaware. In particular, the Court found the ANDA filing “realistically establish[es] a plan to market.”[5] They also stated that, while Mylan’s conduct indicated that it planned to make direct sales of its generic product into the forum state, “even if Mylan does not sell its drugs directly into Delaware, it has a network of independent wholesalers and distributors with which it contracts to market the drugs in Delaware. Such directing of sales into Delaware is sufficient for minimum contacts.”[6] However, the facts in Acorda included additional evidence showing Mylan’s intent to market a generic drug product in the forum state, including Mylan having registered to do business in Delaware, appointed an agent to accept service of process there, and registered with the Delaware Board of Pharmacy as a licensed “Pharmacy-Wholesale” and a “Distributor/Manufacturer CSR.”[7] Thus, SB and Formycon argued that Acorda did not hold that filing an ANDA or aBLA seeking approval to market a product throughout the United States, or contracting with distributors to sell throughout the United States, necessarily evidenced the intent to market the generic or biosimilar drug product in each individual state sufficient to establish personal jurisdiction in any given state.

In the Samsung Bioepis opinion, the Court explained that, like in Acorda, each foreign defendant had engaged in conduct indicating an intent to distribute its drug product nationwide in the U.S. (including in the forum state of West Virginia) by filing an aBLA with the FDA, serving a Notice of Commercial Marketing expressing an intent to begin marketing upon FDA approval, and engaging with partner companies to commercialize and distribute its drug product without excluding any individual U.S. states from the distribution agreement. Although both defendants asserted that they would not be responsible for any decision-making regarding U.S. commercialization because the distribution, marketing, or sales of their respective drug products would be handled solely by non-party partner companies, the Court rejected that argument, pointing out that it had already rejected a similar argument in Acorda “[c]onsistent with the practical focus of the constitutional standard.”[8]

Additionally, the Court was unpersuaded that, as the defendants contended, Regeneron needed to show affirmative evidence that they were expressly targeting West Virginia as a market. Instead, the Court determined that there was “simply no good reason, under the constitutional standard, for demanding such singling-out evidence as a substitute for persuasive evidence of nationwide targeting without a carveout.”[9] In this regard, the Court suggested that, while each defendant’s aBLA does not identify any parts of the U.S. as places where it does not intend to market and distribute the approved product, it could have excluded the forum state as a target for commercialization by, for example, selecting distributors that only reached a limited region of the U.S. (and not the forum state).

As a final note, during oral argument, Judge Moore had alluded to a possible application of Fed. R. Civ. P. 4(k)(2), which provides that a court may exercise personal jurisdiction over a defendant who is not subject to jurisdiction in any state’s courts. In response, Formycon’s counsel asserted that Rule 4(k)(2) did not apply based on Formycon’s voluntary waiver of personal jurisdiction in the state of Washington. Ultimately, having found SB’s and Formycon’s conduct sufficient to meet the minimum-contacts requirement, the Court declined in its opinion to further address whether any alternative means of establishing specific personal jurisdiction, such as Rule 4(k)(2), would have applied here.

[1] Regeneron Pharms, Inc. v. Mylan Pharms Inc., No. 24-2009 et al.; Regeneron Pharms, Inc. v. Mylan Pharms Inc., No. 24-1965 et al. The Court issued a precedential opinion in the SB case, authored by Judge Taranto, and a per curiam opinion addressing additional arguments specific to Formycon’s case.

[2] Acorda Therapeutics Inc. v. Mylan Pharms. Inc., 817 F.3d 755 (Fed. Cir. 2016).

[3] No. 24-1965 at 13; see also No. 24-2009 at 7-8.

[4] No. 24-1965 at 7, 15; see also No. 24-2009 at 7-8.

[5] Acorda, 817 F.3d. at 761.

[6] Id. at 763.

[7] Id.

[8] No. 24-1965 at 15.

[9] Id.

The Federal Circuit recently reversed a District of Delaware decision that invalidated claims of Novartis’s Orange Book listed patent, U.S. Patent No. 8,101,659 (the “’659 patent”), for its blockbuster drug Entresto®, a combination drug used to treat heart failure.

Following a three-day bench trial, Judge Andrews found the ’659 patent not invalid for obviousness, lack of enablement, or indefiniteness, but invalid for lack of written description.[1] On appeal, the Federal Circuit reversed the district court’s finding of inadequate written description and affirmed the other findings that the patent was not invalid.[2]

While not specific to biosimilar law, this case addresses the effect of post-filing discoveries on written description in the pharmaceutical context. The ruling reinforces the principle that inventions or discoveries arising after the filing date do not necessarily invalidate claims directed to an earlier underlying invention that is described and enabled by the specification.

Background

Novartis’s Entresto®, approved by the U.S. Food & Drug Administration (FDA) in 2015, combines valsartan, an angiotensin receptor blocker (ARB), and sacubitril, a neutral endopeptidase (NEP) inhibitor. Entresto® includes valsartan and sacubitril in a specific form known as a “complex,” which combines the two drugs into a single unit-dose-form through weak, non-covalent bonds.[3] Entresto® was initially approved with an indication to treat heart failure ejection fraction. In 2019, the drug was additionally approved for the treatment of heart failure in children, and, in 2021, it was approved for the treatment of heart failure with preserved ejection fraction.[4] In 2023, sales of Entresto® in the U.S. totaled more than $3 billion.[5]

In 2019, MSN Pharmaceuticals, among other generic manufacturers, submitted an Abbreviated New Drug Application (ANDA) seeking FDA approval to market and sell a generic version of Estresto®.[6] Novartis sued MSN and other generic companies, alleging infringement of the ’659 patent, which covers a pharmaceutical composition comprising valsartan and sacubitril.[7] The sole independent claim of the ’659 patent recites:

1. A pharmaceutical composition comprising:

(i) the AT 1-antagonist valsartan or a pharmaceutically acceptable salt thereof;

(ii) the NEP inhibitor N-(3-carboxy-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-2R-methylbutanoic acid ethyl ester or (2R,4S)-5-biphenyl-4-yl-4(3-carboxy-propionyl amino)-2-methyl-pentanoic acid or a pharmaceutically acceptable salt thereof; and

(iii) a pharmaceutically acceptable carrier;

wherein said (i) AT 1-antagonist valsartan or pharmaceutically acceptable salt thereof and said (ii) NEP inhibitor N-(3-carboxy-1-oxopropyl)-(4S)-(p-phenylphenylmethyl)-4-amino-2R-methylbutanoic acid ethyl ester or (2R,4S)-5-biphenyl-4-yl-4(3-carboxy-propionyl amino)-2-methyl-pentanoic acid or pharmaceutically acceptable salt thereof, are administered in combination in about a 1:1 ratio.[8]

During claim construction, the court construed the claim term “in combination” as bolded above. The construction dispute centered on whether “in combination” limited the claim to administration of valsartan and sacubitril “as two separate components,” which MSN proposed to support its non-infringement argument.[9] Novartis argued, and the district court agreed, that the claim was not so limited, and that the term should be given its plain and ordinary meaning.[10] After Markman, MSN, whose proposed generic comprised a “complex” of non-covalently bonded valsartan and sacubitril, stipulated to infringement.

The District Court’s Decision

The district court was unpersuaded by MSN’s obviousness arguments because, despite the known synergistic effects of ARB-NEP inhibitor combinations, the court found MSN failed to provide clear and convincing evidence that a person of ordinary skill in the art (POSA) would have been motivated to combine valsartan and sacubitril in 2002.[11] Specifically, the court found that sacubitril had never been tested on humans or in an animal model of hypertension and heart failure, and results for other NEP inhibitors that had been tested were discouraging.[12]

As to written description and enablement, “guided by the understanding that the court had ‘construed the asserted claims to cover valsartan and sacubitril as a physical combination and as a complex,’ the parties’ dispute centered on whether the ’659 patent was required to enable and describe such complexes.”[13]

MSN argued that the patent failed to enable and describe the full scope of the claims, while Novartis argued that a complex of valsartan and sacubitril was an after-arising invention that need not have been enabled or described.[14] Specifically, Novartis argued that its “later, nonobvious discovery of valsartan and sacubitril in the form of a complex should not invalidate the ’659 patent claims to Novartis’s earlier invention: the novel combination of valsartan and sacubitril.”[15] The district court agreed with Novartis on enablement, but disagreed on written description.

As to enablement, the district court reasoned that enablement is judged as of the priority date, and therefore later-existing state of the art may not be properly considered in the enablement analysis.[16] The district court found that MSN failed to establish that pharmaceutical complexes in general were known or nascent technology in 2002, and therefore the ’659 patent need not enable them.[17]

As for written description, however, the district court found “the facts that helped [Novartis] with respect to enablement proved fatal for written description,” because it was undisputed that complexes were unknown to a POSA, and thus the Novartis scientists “by definition, could not have possession of, and disclose, the subject matter” of the complexes in 2002.[18]

The Federal Circuit’s Reversal

The Federal Circuit reversed the district court’s written description ruling. The court emphasized that the issue is “not whether the ’659 patent describes valsartan-sacubitril complexes,” because “the ’659 patent does not claim valsartan-sacubitril complexes.”[19] The court noted that the district court rejected MSN’s proposed construction which had sought to exclude from the scope of the claims the accused product: a valsartan-sacubitril complex.[20] Instead, the term was given its plain and ordinary meaning: “wherein said [valsartan and sacubitril] are administered in combination.” The Federal Circuit found such combinations were “plainly described throughout the specification.”[21]

The Federal Circuit explained: “the fact that the ’659 patent does not describe a complexed form of valsartan and sacubitril” is irrelevant to validity, because a “complex”—which was not discovered until four years after the priority date of the ’659 patent—“is not what is claimed.”[22] The court noted that if the claims had been “construed to claim valsartan-sacubitril complexes . . . that construction would have been error,” because claim interpretation must determine “the meaning of the claims to one of ordinary skill in the art at the time of the invention,” and such complexes were unknown at that time.[23]

The court also held that the district court’s reasoning that the claims were “construed to cover complexes of valsartan and sacubitril,” was erroneous because it “conflated the distinct issues of patentability and infringement, which led [the district court] to astray in evaluating written description.”[24] The court reiterated that claims are not construed “to cover” or “not to cover” the accused product.[25] ‘“It is only after the claims have been construed without reference to the accused device that the claims, as so construed, are applied to the accused device to determine infringement.’”[26]

Implications for Pharmaceutical Patents

This decision reinforces the principle that an after-arising invention does not render invalid for lack of written description a claim that is properly construed as broad enough to encompass it, provided the specification supports and enables what is claimed. This is particularly relevant in the pharmaceutical field, where later research often leads to refinements and discoveries involving existing drugs. Practitioners should carefully analyze the state of the art and the appropriate claim construction when developing arguments regarding written description.

[1] In re Entresto (Sacubitril/Valsartan) Pat. Litig., No. 20-md-2930, 2023 WL 4405464 (D. Del. July 7, 2023).

[2] In re Entresto, No. 23-2218, 2025 WL 63577, Slip Op. at 3 (Fed. Cir. Jan. 10, 2025) (precedential).

[3] Id. at 4.

[4] Id.

[5] Id.

[6] Id. at 6.

[7] Id.

[8] U.S. Patent No. 8,101,659 at Claim 1 (emphasis added).

[9] In re Entresto, 2021 WL 2856683, at *3.

[10] Id.

[11] In re Entresto, 2023 WL 4405464 at *12-13.

[12] Id.

[13] Novartis, 23-2218 at 10 (quoting In re Entresto, 2023 WL 4405464 at *17) (emphasis added)).

[14] In re Entresto, 2023 WL 4405464 at *17-21.

[15] Novartis, 23-2218 at 10.

[16] In re Entresto, 2023 WL 4405464 at *19.

[17] Id. at *20.

[18] Id. at *21-22.

[19] Novartis, 23-2218 at 12 (emphasis in original).

[20] Id. (emphasis added).

[21] Id.

[22] Id. at 13.

[23] Id. at 14, n.5 (quoting SmithKline Beecham Corp. v. Apotex Corp., 403 F.3d 1331, 1338 (Fed. Cir. 2005)) (emphases in original).

[24] Id. at 13 (emphasis in original).

[25] Id. at 14.

[26] Id. (quoting SRI Int’l v. Matsushita Elec. Corp. of Am., 775 F.2d 1107, 1118 (Fed. Cir. 1985)).

In our previous article, we reported that the Federal Circuit affirmed the district court’s decision requiring Teva to delist certain patents related to its Teva’s ProAir® HFA metered-dose inhaler from the FDA’s Orange Book. Following a request from Teva for an en banc rehearing, the Federal Circuit stayed the delisting order on January 22, 2025. This stay delays the delisting of Teva’s patents from the Orange Book, allowing Teva to maintain its current patent listings pending resolution of the petition for rehearing en banc. The outcome of this en banc rehearing will have significant implications for both brand name drug product developers and generic drug developers. We will continue to monitor further developments in this case and provide insight and updates as they become available.

  • FDA and EMA both approve biosimilar versions of Stelara® (ustekinumab), Eylea® (aflibercept) and Prolia® and Xgeva® (denosumab).
  • FDA approves 19 biosimilars in 2024.

Biosimilars, once a niche segment in the pharmaceutical industry, are now making a significant impact on global healthcare.  These products are highly similar to an already-approved reference product, offering a more affordable treatment option without compromising on safety or efficacy.  As biosimilars gain traction worldwide, regulatory bodies like the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) play a critical role in shaping their market introduction.  While both agencies share similar goals of ensuring patient safety and promoting access to high-quality therapeutics, their regulatory pathways and approval trends show notable differences.

One such difference is that the EMA has historically been quicker than the FDA in approving biosimilars.  Since 2005, the biosimilar regulatory framework in Europe has been implemented through the Committee for Medicinal Products for Human Use (CHMP) under the EMA.  The CHMP provides initial assessments for marketing authorization of new medicines that are ultimately approved centrally by the EMA.  Since Sandoz’s somatotropin biosimilar, Omnitrope®, was first authorized on April 12, 2006, an additional 112 applications have been approved in Europe.  Sixteen of the authorizations have been withdrawn post-approval (Table 1).  On average, the EMA takes about 1-2 years from submission of a biosimilar application to approval.

In contrast, the FDA’s biosimilar approval process has been relatively slow, with initial approval times averaging 3-4 years for the first generation of biosimilars.  This delay in approval is partly due to the FDA’s more rigorous evaluation of biosimilars and the additional data required to achieve interchangeability designation.  Additionally, the U.S. did not implement a regulatory framework for biosimilar evaluation until after enactment of the Biologics Price Competition and Innovation Act (BPCIA) of 2009.  As the EMA had already approved over a dozen biosimilars by this time, Europe had a significant head start on both the number of approved biosimilars and the regulatory process for approving more.  Sandoz’s filgrastim biosimilar, Zarxio®, received the first U.S. approval in 2015, whereas nine filgrastim biosimilars have been approved in Europe dating back to multiple authorizations in 2008.  Despite the FDA’s relatively slower biosimilar approval pace, the U.S. biosimilar market has managed to grow continuously over the past decade.  Subsequent to Zarxio®’s approval, 63 other biosimilar drugs have gained U.S. approval to date including 14 interchangeable products (Table 2).

As illustrated in the following graph, while the EU’s significant head start and higher approval rate led to an imbalance in the number of biosimilar drugs available in the respective markets, the FDA has increased the rate of approval in recent years.  In 2024 alone, the FDA approved 19 biosimilars, the most approvals in a single year by either regulatory body to date.

Despite the high number of approvals in 2024, launches of several FDA-approved biosimilars, such as aflibercept and ustekinumab, are delayed due to patent litigations or settlements between parties.  Additionally, there are often  regulatory hurdles and costs faced by biosimilar applicants that deter or delay biosimilar products from reaching the U.S. market.

Looking forward, there are currently 38 biosimilar applications under review by the EMA for marketing authorization (Table 3).  As an increasing number of patents expire on blockbuster biologic drugs, the number of abbreviated biologics license applications is also increasing.  Biosimilars for more than 31 different original biologics are currently navigating biosimilar pathways or are in late stage development in the U.S. (Table 4).  

Table 1. European Medicines Agency List of Approved Biosimilar Drugs.

Biosimilar Proprietary NameDrug ProductOwnerStatus*Authorization/ Withdrawal Date
Abasaglar
(previously Abasria)		Insulin GlargineEli Lilly Regional
Operations GmbH		Authorized9/9/2014
AbevmyBevacizumabMylan IRE Healthcare LimitedAuthorized4/21/2021
AbseamedEpoetin AlfaMedice Arzneimittel Pütter GmbH & Co. KgAuthorized8/28/2007
AccofilFilgrastimAccord Healthcare LtdAuthorized9/18/2014
AdmelogInsulin lisproSanofiAuthorized5/19/2017
AlpheonRecombinant Human
Interferon Alfa-2a		Biopartners GmbHRefused–
AlymsysBevacizumabMabxience Research SLAuthorized3/26/2021
AmgevitaAdalimumabAmgen EuropeAuthorized3/22/2017
AmsparityAdalimumabPfizer Europe MA EEIGAuthorized2/13/2020
AvziviBevacizumabFGK Representative Service GmbHAuthorized7/26/2024
AybintioBevacizumabSamsung Bioepis NL B.V.Authorized8/20/2020
BekemvEculizumabAmgen Technology UCAuthorized4/19/2023
BemfolaFollitropin AlfaGedeon Richter Plc.Authorized3/27/2014
BenepaliEtanerceptSamsung Bioepis
Uk Limited (Sbuk)		Authorized1/14/2016
BinocritEpoetin AlfaSandoz GmbHAuthorized8/28/2007
BiograstimFilgrastimAbz-Pharma GmbHWithdrawn9/15/2008
BlitzimaRituximabCelltrionAuthorized7/13/2017
ByoovizRanibizumabSamsung BioepisAuthorized8/18/2021
CyltezoAdalimumabBoehringer Ingelheim International GmbHAuthorized Withdrawn11/10/2017 1/15/2019
DyrupegPegfilgrastimCuraTeQ BoilogiceWithdrawn6/08/2023
EksunbiUstekinumabSamsung Bioepis NL B.V.Authorized9/12/2024
Epoetin Alfa HexalEpoetin AlfaHexal AgAuthorized8/28/2007
EpysqliEculizumabSamsung Bioepis NL B.V.Authorized5/26/2023
EquidacentBevacizumabCentus Biotherapeutics Europe LimitedAuthorized Withdrawn9/25/2020 10/11/2021
ErelziEtanerceptSandoz GmbHAuthorized6/23/2017
Filgrastim HexalFilgrastimHexal AgAuthorized6/2/2009
Filgrastim ratiopharmFilgrastimRatiopharm GmbHWithdrawn9/15/2008
FlixabiInfliximabSamsung Bioepis
Uk Limited (SBUK)		Authorized5/26/2016
FulphilaPegfilgrastimMylan S.A.S.Authorized11/20/2018
FymskinaUstekinumabFormycon AGAuthorized9/25/2024
GrastofilFilgrastimApotex Europe BvAuthorized10/18/2013
GrasustekPegfilgrastimJuta Pharma GmbHAuthorized4/26/2019
HalimatozAdalimumabSandoz GmbHAuthorized Withdrawn7/26/2018 12/18/2020
HefiyaAdalimumabSandoz GmbHAuthorized7/26/2018
HerwendaTrastuzumabSandoz GmbHAuthorized11/15/2023
HerzumaTrastuzumabCelltrion Healthcare Hungary Kft.Authorized2/9/2018
HukyndraAdalimumabStada Arzneimittel AGAuthorized11/15/2021
HulioAdalimumabMylan S.A.S.Authorized9/19/2018
HyrimozAdalimumabSandoz GmbHAuthorized7/26/2018
IdacioAdalimumabFresenius Kabi Deutschland GmbHAuthorized4/2/2019
ImraldiAdalimumabSamsung Bioepis UK Limited (SBUK)Authorized8/24/2017
ImuldosaUstekinumabAccord Healthcare S.L.U.Authorized12/12/2024
InflectraInfliximabHospira Uk LimitedAuthorized9/10/2013
InhixaEnoxaparin SodiumTechdow Europe AbAuthorized9/15/2016
InpremziaInsulin humanBaxter Holding B.V.Authorized Withdrawn4/25/2022 4/20/2023
Insulin aspart SanofiInsulin aspartateSanofi-Aventis groupeAuthorized7/26/2020
JubbontiDenosumabSandoz GmbHAuthorized5/16/2024
KanjintiTrastuzumabAmgen/AllerganAuthorized5/16/2018
KaulivTeriparatodeStrides Pharma LimitedAuthorized1/12/2023
Kirsty (previously Kixelle)Insulin aspartMylanAuthorized2/8/2021
KromeyaAdalimumabFresenius Kabi Deutschland GmbHAuthorized Withdrawn4/2/2019 12/17/2019
LextemyBevacizumabMylan IRE Healthcare LimitedAuthorized Withdrawn4/21/2021 6/21/2021
LibmyrisAdalimumabStada Arzneimittel AGAuthorized11/12/2021
LivogivaTeriparatideTheramex Ireland LimitedAuthorized8/27/2020
LusdunaInsulin GlargineMerck Sharp &
Dohme Limited		Authorized Withdrawn4/1/2017 10/29/2018
LyumjevInsulin lisproEli Lilly Nederland B.V.Authorized3/24/2020
MovymiaTeriparatideStada Arzneimittel AgAuthorized1/11/2017
MvasiBevacizumabAmgen Europe B.V.Authorized1/15/2018
NepextoEtanerceptMylan and LupinAuthorized6/4/2020
NivestimFilgrastimHospira Uk LtdAuthorized6/8/2010
NyvepriaPegfilgrastimPfizer Europe MA EEIGAuthorized11/19/2020
OgivriTrastuzumabViatrisAuthorized12/12/2018
OmlycloOmalizumabCelltrion Healthcare Hungary Kft,Authorized5/16/2024
OmnitropeSomatropinSandoz GmbHAuthorized4/12/2006
OnbevziBevacizumabSamsung Bioepis Co., Ltd.Authorized Withdrawn1/13/2021 10/24/2024
OntruzantTrastuzumabSamsung Bioepis Co., Ltd.Authorized11/17/2017
OpuvizAfliberceptSamsung Bioepis NL B.V.Authorized9/19/2024
OtulfiUstekinumabFresenius Kabi Deutschland GmbHAuthorized9/25/2024
OvaleapFollitropin AlfaTeva Pharma B.V.Authorized9/27/2013
OyavasBevacizumabSTADA Arzneimittel AGAuthorized3/26/2021
Pegfilgrastim Mundipharma (Cegfila)PegfilgrastimMundipharma Biologics S.L.Authorized12/19/2019
PelgrazPegfilgrastimAccord Healthcare LimitedAuthorized9/25/2018
PelmegPegfilgrastimCinfa Biotech S.L.Authorized11/20/2018
PyzchivaUstekinumabSamsung Bioepis NL B.V.Authorized4/19/2024
QutavinaTeriparatideEuroGenerics Holdings BVAuthorized Withdrawn8/31/2020 11/26/2020
Ranibizumab MidasRanibizumabMidas Pharma GmbHAuthorized9/19/2024
RanivisioRanibizumabMidas Pharma GmbHAuthorized8/25/2022
RatiograstimFilgrastimRatiopharm GmbHAuthorized9/15/2008
RemsimaInfliximabCelltrion Healthcare
Hungary Kft.		Authorized9/10/2013
RetacritEpoetin ZetaHospira Uk LimitedAuthorized12/18/2007
RimmyrahRanibizumabQilu Pharma Spain S.L.Authorized1/05/2024
RitemviaRituximabCelltrionAuthorized Withdrawn7/13/2017 6/21/2021
Rituzena (previously Tuxella)RituximabCelltrionAuthorized Withdrawn7/13/2017 4/12/2019
RixathonRituximabSandoz GmbHAuthorized6/15/2017
RiximyoRituximabSandoz GmbHAuthorized6/15/2017
RuxienceRituximabPfizer Europe MA EEIGAuthorized4/1/2020
SemgleeInsulin glargineMylan S.A.S.Authorized3/27/2018
SilapoEpoetin ZetaStada Arzneimittel AgAuthorized12/18/2007
SolumarvInsulin HumanMarvel Lifesciences LtdRefused–
SolymbicAdalimumabAmgen EuropeAuthorized Withdrawn3/22/2017 6/15/2018
SondelbayTeriparatideAccord Healthcare S.L.U.Authorized3/24/2022
StimufendPegfilgrastimFresenius Kabi Deutschland GmbHAuthorized3/28/2022
TerrosaTeriparatideGedeon Richter Plc.Authorized1/4/2017
TevagrastimFilgrastimTeva GmbHAuthorized9/15/2008
ThorinaneEnoxaparin SodiumPharmathen S.A.Authorized9/15/2016
TrazimeraTrastuzumabPfizerAuthorized7/26/2018
Truvelog Mix 30Insulin aspartSanofi Winthrop IndustrieAuthorized4/25/2022
TruximaRituximabCelltrion Healthcare
Hungary Kft.		Authorized2/17/2017
TuznueTrastuzumabPrestige Biopharma BelgiumAuthorized9/19/2024
TyenneTocilizumabFresenius Kabi Deutschland GmbHAuthorized9/15/2023
TyrukoNatalizumabSandoz GmbHAuthorized9/22/2023
UdenycaPegfilgrastimCoherus/ERA Consulting GmbHAuthorized Withdrawn9/25/2018 2/4/2021
UzpruvoUstekinumabStada ArzneimittelAuthorized1/05/2024
VegzelmaBevacizumabCelltrion HealthcareAuthorized8/17/2022
WezenlaUstekinumabAmgen Technology UCAuthorized6/20/2024
WyostDenosumabSandoz GmbHAuthorized5/17/2024
XimluciRanibizumabSTADA Arzneimittel AGAuthorized3/26/2022
YesafiliAfliberceptBiosimilar Collaborations Ireland LimitedAuthorized7/20/2023
YuflymaAdalimumabCelltrion Healthcare
Hungary Kft.		Authorized2/11/2021
ValtropinSomatropinBiopartners GmbHWithdrawn4/24/2006
ZarzioFilgrastimSandoz GmbHAuthorized2/6/2009
ZercepacTrastuzumabAccord Healthcare S.L.U.Authorized7/28/2020
ZesslyInfliximabSandoz GmbHAuthorized5/18/2018
ZiextenzoPegfilgrastimSandoz GmbHAuthorized11/22/2018
ZirabevBevacizumabPfizerAuthorized2/14/2019

Table 2. U.S. Food and Drug Administration List of Approved Biosimilar Drugs.

No.Drug ProductCompanyReference Product and SponsorMarketing StatusFDA Approval Date
64Steqeyma (Ustekinumab-stba)CelltrionJanssen Stelara®Not Available Launch Expected February 202512/17/2024
63Yesintek (ustekinumab-kfce)Biocon Biologics Inc.Janssen Stelara®Not Available Launch Expected February 202511/29/2024
62Imuldosa (ustekinumab-srlf)Accord BiopharmaJanssen Stelara®Not Available Launch Expected May 202510/10/2024
61Otulfi (ustekinumab-aauz)Fresenius KabiJanssen Stelara®Not Available Launch Expected February 20259/27/2024
60Pavblu (aflibercept-ayyh)AmgenRegeneron Eylea®Not Available8/23/2024
59Enzeevu (aflibercept-abzv)SandozRegeneron Eylea®Not Available8/09/2024
58Epysqli (eculizumab-aagh)Samsung BioepisAlexion Soliris®Not Available7/19/2024
57Ahzantive (aflibercept-mrbb)Formycon AGRegeneron Eylea®Not Available6/28/2024
56Nypozi (filgrastim-txid)Tanvex BiopharmaAmgen Neupogen®Not Available6/28/2024
55Pyzchiva (ustekinumab-ttwe)Samsung BioepisJanssen Stelara®Not Available Launch Expected February 20256/28/2024
54Bkemv (eculizumab-aeeb)AmgenAlexion Soliris®Not Available Launch Expected March 20255/28/2024
53Yesafili (aflibercept-jbvf)Biocon BiologicsRegeneron Eylea®Not Available Launch Delayed to 20255/20/2024
52Opuviz (aflibercept-yszy)Samsung BioepisRegeneron Eylea®Not Available Launch Delayed to 20255/20/2024
51Hercessi (trastuzumab-strf)Accord BiopharmaGenentech Herceptin®Launched November 20244/25/2024
50Selarsdi (ustekinumab-aekn)AlvotechJanssen Stelara®Not Available Launch Expected February 20254/16/2024
49Tyenne (tocilizumab-aazg)Fresenius KabiGenentech Actemra®Launched April 20243/05/2024
48Jubbonti (denosumab-bbdz)SandozAmgen Prolia®Not Available Launch Expected May 20253/05/2024
47Wyost (denosumab-bbdz)SandozAmgen Xgeva®Not Available Launch Expected May 20253/05/2024
46Simlandi (adalimumab-ryvk)AlvotechAbbVie Humira®Launched May 20242/23/2024
45Avzivi (bevacizumab-tnjn)Bio-thera SolutionsGenentech Avastin®Not Available12/06/2023
44Wezlana (ustekinumab-auub)AmgenJanssen Stelara®Not Available Launch Delayed to 202510/31/2023
43Tofidence (tocilizumab-bavi)BiogenGenentech Actemra®Launched May 20249/29/2023
42Tyruko (natalizumab-sztn)SandozBiogen Tysabri®Launched February 20248/24/2023
41Yuflyma (adalimumab-aaty)CelltrionAbbVie Humira®Launched July 20235/23/2023
40Idacio (adalimumab-aacf)Fresenius KabiAbbVie Humira®Launched July 202312/13/2022
39Vegzelma (bevacizumab-adcd)CelltrionGenentech Avastin®Launched April 20239/27/2022
38Stimufend (pegfilgrastim-fpgk)Fresenius KabiAmgen Neulasta®Launched February 20239/01/2022
37Cimerli (ranibizumab-eqrn)SandozGenentech Lucentis®Launched October 20228/02/2022
36Fylnetra (pegfilgrastim-pbbk)Kashiv BiosciencesAmgen Neulasta®Launched May 20235/26/2022
35Alymsys (bevacizumab-maly)AmnealGenentech Avastin®Launched October 20224/13/2022
34Releuko (filgrastim-ayow)Kashiv Biosciences & Amneal PharmaceuticalsAmgen Neupogen®Launched November 20222/28/2022
33YusimryTM (adalimumab-aqvh)CoherusAbbVie Humira®Launched July 2023  12/20/2021
32RezvoglarTM (insulin glargine-aglr)Eli LillySanofi Lantus®Launched April 2023  12/20/2021
31ByoovizTM (ranibizumab-nuna)Samsung Bioepis and BiogenGenentech Lucentis®Launched July 20229/17/2021
30SemgleeTM (insulin glargine-yfqn) INTERCHANGEABLEViatris and Biocon BiologicsSanofi Lantus®Launched November 20217/28/2021
29RiabniTM (rituximab-arrx)AmgenBiogen and Genentech Rituxan®Launched January 202112/17/2020
28HulioTM (adalimumab-fkjp)MylanAbbVie Humira®Launched July 20237/6/2020
27NyvepriaTM (pegfilgrastim-apgf)PfizerAmgen Neulasta®Launched January 20216/10/2020
26AvsolaTM (infliximab-axxq)AmgenJanssen Remicade®Launched July 202012/6/2019
25AbriladaTM (adalimumab-afzb)PfizerAbbVie Humira®Launched November 202311/15/2019
24ZiextenzoTM (pegfilgrastim-bmez)SandozAmgen Neulasta®Launched November 201911/4/2019
23HadlimaTM (adalimumab-bwwd)Samsung BioepisAbbVie Humira®Launched July 20237/23/2019
22RuxienceTM (rituximab-pvvr)PfizerBiogen and Genentech Rituxan®Launched January 20207/23/2019
21ZirabevTM (bevacizumab-bvzr)PfizerGenentech/Roche Avastin®Launched December 20196/28/2019
20KanjintiTM (trastuzumab-anns)AmgenRoche/Genentech Herceptin®Launched July 20196/13/2019
19EticovoTM (etanercept-ykro)Samsung BioepisAmgen Enbrel®

Not available4/25/2019
18TrazimeraTM (trastuzumab-qyyp)PfizerRoche/Genentech Herceptin®Launched February 20203/11/2019
17Ontruzant™ (trastuzumab-dttb)Samsung BioepisRoche/Genentech Herceptin®Launched April 20201/18/2019
16Herzuma™ (trastuzumab-pkrb)Celltrion and TevaRoche/Genentech Herceptin®Launched March 202012/14/2018
15Truxima™ (rituximab-abbs)Celltrion and TevaBiogen and Genentech Rituxan®Launched November 201911/28/2018
14Udenyca™ (pegfilgrastim-cbqv)Coherus BioSciencesAmgen Neulasta®Launched January 201911/2/2018
13Hyrimoz™ (adalimumab-adaz)SandozAbbVie Humira®Launched July 202310/30/2018
12NivestymTM (filgrastim-aafi)PfizerAmgen Neupogen®Launched October 20187/20/2018
11FulphilaTM (pegfilgrastim-jmdb)Mylan/BioconAmgen Neulasta®Launched July 20186/4/2018
10Retacrit® (epoetin alfa-epbx)PfizerJanssen Procrit®Launched November 20185/15/2018
9Ixifi® (infliximab-qbtx)PfizerJanssen Remicade®Not Available12/13/2017
8Ogivri® (trastuzumab-dkst)Mylan/BioconRoche/Genentech Herceptin®Launched December 201912/01/2017
7MvasiTM (bevacizumab-awwb)Amgen AllerganGenentech/Roche Avastin®Launched July 20199/14/2017
6CyltezoTM (adalimumab-adbm) INTERCHANGEABLEBoehringer Ingelheim International GmbHAbbVie Humira®Launched July 20238/25/2017
5Renflexis® (infliximab-abda)Samsung BioepisJanssen Remicade®Launched July 20174/21/2017
4Amjevita® (adalimumab-atto)AmgenAbbVie Humira®Launched January 20239/23/2016
3Erelzi ® (etanercept-szzs)SandozAmgen Enbrel®
(etanercept)		Not Available8/30/2016
2Inflectra® (infliximab-dyyb)Celltrion/PfizerJanssen Remicade®Launched November 20164/05/2016
1Zarxio® (filgrastim-sndz)SandozAmgen Neupogen®Launched
September 2015		03/06/2015

Table 3. European Medicines Agency List of Biosimilars Under Evaluation for Marketing Approval (Source: EMA list of applications for new human medicines compiled on December 2, 2024 and published on December 9, 2024).

Drug ProductReference Product Proprietary NameReference Product SponsorNumber of Applications
AfliberceptEylea®Regeneron6
DenosumabProlia®Amgen20
FilgrastimNeupogen®Amgen1
GolimumabSimponi®Janssen1
Insulin aspart  1
Insulin glargine  1
Insulin human  1
Insulin lispro  1
PegfilgrastimNeulasta®Amgen2
RilonaceptArcalyst®Regeneron1
TeriparatideForteo®/Forsteo®Eli Lilly1
TocilizumabActemra®Genentech1
TrastuzumabHerceptin®Roche/Genentech1

Table 4. Biologics having already expired or nearing primary patent expiry in the U.S. and biologics that have biosimilars in the regulatory pipeline. 

Drug ProductPrimary U.S. Patent Expiry*
OnabotulinumtoxinA (Botox®)Primary patents long-expired, various use patents pending
Insulin products (various)Primary patents long-expired
Filgrastim (Neupogen®)2013
Epoetin alfa (Epogen®)2013
Pegfilgrastim (Neulasta®)2015
Adalimumab (Humira®)2016
Rituximab (Rituxan®)2018
Cetuximab (Erbitux®)2018
Omalizumab (Xolair®)2018
Infliximab (Remicade®)2018
Teriparatide (Forteo®)2019
Bevacizumab  (Avastin®)2019
Trastuzumab (Herceptin®)2019
Tocilizumab (Acetmra®)2019
Abatacept (Orencia®)2019
Ranibizumab (Lucentis®)2020
Panitumumab (Vectibix®)2020
Eculizumab (Soliris®)2021
Aflibercept (Eylea®)2023
Denosumab (Prolia® and Xgeva®)2023
Palivizumab (Synagis®)2023
Ustekinumab (Stelara®)2023
Certolizumab pegol (Cimzia®)2024
Golimumab (Simponi®)2024
Darbepoetin alfa (Aranesp®)2024
Pertuzumab (Perjeta®)2024
Canakinumab (Ilaris®)2024
Benralizumab (Fasenra®)2024
Ipilimumab (Yervoy®)2025
Natalizumab (Tysabri®)2027
Etanercept (Enbrel®)2028
Pembrolizumab (Keytruda®)2028
Ocrelizumab (Ocrevus®)2028
Nivolumab (Opdivo®)2028
Tezepelumab (Tezspire®)2028
Anifrolumab (Saphnelo®)2029
Vedolizumab (Entyvio®)2031
Tremelimumab (Imjudo®)2031
Nirsevimab (Beyfortus®)2035
Ravulizumab (Ultomiris®)2035

*Expiration dates are estimated and subject to change, for example, if pending patent term extension applications are granted.

Disclaimer: The information contained in this posting does not, and is not intended to, constitute legal advice or express any opinion to be relied upon legally, for investment purposes or otherwise. If you would like to obtain legal advice relating to the subject matter addressed in this posting, please consult with us or your attorney. The information in this post is also based upon publicly available information, presents opinions, and does not represent in any way whatsoever the opinions or official positions of the entities or individuals referenced herein.

Since the America Invents Act (“AIA”) established a new venue for hearing patent disputes, the Patent Trial and Appeal Board (“PTAB”), much ink has been spilled regarding the impacts of this forum on patent litigation and the overall intellectual property strategies employed by both patentees and challengers. The Promoting and Respecting Economically Vital American Innovation Leadership (“PREVAIL”) Act was recently sent to the Senate from the Committee of the Judiciary after an 11-10 vote, and it proposes regulations that could significantly change the ways that PTAB proceedings are conducted. What follows is a summary of the Act’s most substantive proposals.

The Act would implement a standing requirement for petitioners in line with what is required to bring a declaratory judgement action for invalidity in Article III courts. The Act also sets forth regulations that would estop challengers from raising arguments that were previously asserted in another PTAB proceeding or Article III court against the same patent; and challengers would no longer be able to assert invalidity against the same patent in both forums at the same time. The Act would also broaden the PTAB’s standard for determining the real parties in interest to a dispute. 

In addition to new standing requirements and procedural definitions, the Act would raise the burden of proof at the PTAB to match that of an Article III court, i.e, a challenger would have the burden to prove patent invalidity by a clear and convincing standard, rather than a preponderance of the evidence. 

Proponents of the PREVAIL Act argue that it is necessary to restore fairness to the PTAB by preventing multiple challengers from working together to bring separate or repeated challenges against a single patent or patent owner. Those in support of the Act also argue that it is necessary to harmonize the laws applied at the PTAB and Article III courts. Senator Coons, who introduced the bill, provided the following explanations for how the Act would solve problems with PTAB trials:

Problem:  Currently, anyone can challenge a patent in the PTAB, even if they are not facing a lawsuit or the threat of a lawsuit. Multiple parties can also work together to bring separate or repeated challenges against a single patent or patent owner—including small businesses or independent innovators with limited resources.  

Solution:  Require standing for PTAB challengers and limit repeated petitions.  The PREVAIL Act requires challengers to have been sued or threatened with a patent infringement lawsuit before filing a PTAB challenge. The bill also limits multiple PTAB challenges against the same patent by prohibiting any entity financially contributing to a PTAB challenge from bringing its own challenge.  

Problem: Although a party must file a PTAB challenge within one year of being sued for infringement, a loophole allows a time-barred party to challenge patents after the PTAB filing deadline expires by joining a PTAB proceeding brought by another party.  

Solution: Close the loophole.  The PREVAIL Act establishes a rebuttable presumption against joinder for a time-barred party and prohibits such a party from maintaining the proceeding after the original challenger settles.

Problem: Currently, the same party can file multiple petitions against the same patent, allowing challengers to paper over weaknesses in their case and increasing costs for patent owners defending their rights.

Solution: Require a party to raise all arguments in one challenge to protect a patent owner’s right to “quiet title” over the invention. The PREVAIL Act limits serial petitions by applying estoppel at the time the challenge is filed, rather than after a PTAB final written decision.

Problem: When validity of a patent is challenged in district court, “clear and convincing” evidence is needed to invalidate the patent. But at the PTAB, a petitioner need only show invalidity by a “preponderance of the evidence” standard. Further, until recently, the PTAB interpreted patent claims under a different standard than the district court. These differences often lead to inconsistent results between the two tribunals.

Solution: Harmonize PTAB claim interpretation and burden of proof with federal district court. The PREVAIL Act requires the PTAB to find a patent invalid by “clear and convincing” evidence and requires the PTAB to interpret claims using the same “plain and ordinary meaning” standard used in federal district court.  

Problem: Some aspects of PTAB proceedings lack transparency. For example, no rules prevent the Director from meddling in a PTAB panel’s decision.  

Solution: Increase transparency. The PREVAIL Act requires the USPTO Director to issue separate written opinions when rehearing PTAB decisions to increase transparency and reduce concerns that the Director unfairly influences PTAB decisions. The bill also prohibits the Director from influencing PTAB panel decisions and requires the Director to establish a code of conduct for PTAB judges.   

Problem: Currently, at least 85% of PTAB proceedings have a co-pending proceeding in another forum, like federal district court. Challengers get several bites at the apple by raising the same or similar validity challenges at the PTAB and the other forum.

Solution: End duplicative patent challenges. The PREVAIL Act requires a party to choose between making its validity challenges before the PTAB or in another forum, such as federal court. The bill also requires a party that is already involved in a separate proceeding to agree not to pursue the claims in their PTAB petition in that court, or any other forum.   

Problem: Often, another forum, such as a federal district court, reviews a challenger’s validity challenge to a patent and enters a final judgment on validity before the PTAB completes its review. Instituting or maintaining a PTAB proceeding after the district court already has decided validity is duplicative, inefficient, and may lead to inconsistent decisions between both tribunals.

Solution: Prioritize prior patent validity decisions. The PREVAIL Act requires the PTAB to deny a petition or dismiss a proceeding if another forum—such as a federal court—has already upheld the validity of the patent at issue.  

Problem: A PTAB challenge or a reexamination request often will assert the same prior art or arguments that the USPTO already considered during another Office proceeding. Multiple proceedings asserting the same prior art and arguments are costly and inefficient.  

Solution: Limit duplicative challenges to a patent within the USPTO.  The PREVAIL Act requires the USPTO to reject a PTAB challenge or a request to reexamine a patent where the challenge or request includes arguments that were previously considered by the USPTO, absent exceptional circumstances.

Problem: Since 2010, approximately $409.8 million in user fees have been diverted from the USPTO.

Solution: Eliminate fee diversion. The PREVAIL Act ends the practice of diverting fees collected by the USPTO to other unrelated federal agencies and programs by establishing a new revolving fund in the U.S. Treasury to ensure the USPTO has the funding necessary for timely and quality examination.  

Problem: Small businesses do not always have the resources they need to navigate the patent system.  

Solution: Support innovative small businesses. The PREVAIL Act supports small businesses by requiring the Small Business Administration to draft two reports examining the impact of patents and abusive demand letters on small businesses.  The bill also expands access to patent-searching databases currently available only in-person at public search facilities. 

Critics of the PREVAIL Act are concerned that it would tilt the balance too far in favor of patentees, potentially undermining the goals of the patent system to promote innovation and fair competition. Among many others, critics are concerned about the impact the Act’s standing provisions would have on individuals who currently have the right to challenge patents at the PTAB (e.g., non-practicing entities), but may lose that ability under the Act’s more restrictive criteria, potentially limiting access to this important mechanism for addressing questionable patents. Others argue that the Act would raise consumer drug prices by making it harder for patient advocacy groups and generics manufacturers to increase competition by challenging wrongfully issued drug patents. Further, critics argue that by restricting access to PTAB proceedings, the Act could reduce the number of challenges brought against questionable patents, allowing invalid patents to remain unaddressed and creating barriers to competition. In addition, critics contend that the provisions could shift patent litigation to federal courts, where proceedings are often more costly and time-consuming than PTAB reviews, which could disproportionately burden smaller businesses and startups with fewer resources. Also, while the PTAB has been touted as a tool in combating abusive practices by “patent trolls” by providing a relatively efficient and cost-effective means of invalidating overly broad or weak patents, critics argue that limiting access to the PTAB could embolden these entities to assert low-quality patents more aggressively. Overall, critics believe the Act would erode the effectiveness of the PTAB, increase litigation costs, and shift the balance of the patent system in a way that harms competition and innovation. They argue that reforms should focus on improving patent quality and accessibility rather than limiting the avenues for challenging questionable patents.

In sum, the PREVAIL Act would change how patent challengers and patent owners proceed before the PTAB. We will continue to monitor and report on the Act as it moves through the Senate. In the meanwhile, potential challengers and patent owners should assess their litigation strategies and planned timing in light of potentially significant changes in PTAB trials.

Sources:

https://www.congress.gov/bill/118th-congress/senate-bill/2220/text

https://ipwatchdog.com/2024/11/21/prevail-act-narrowly-moves-forward-despite-concerns-drug-pricing-impact/id=183421/

On December 20, 2024, the U.S. Court of Appeals for the Federal Circuit issued a significant ruling in the Teva v. Amneal case following oral arguments before the Federal Circuit, which we discussed in our previous article. The Federal Circuit affirmed the district court’s decision that Teva’s patents were improperly listed and must be removed from the Orange Book.[1] The ruling clarifies that the statutory framework for Orange Book listings require listed patents to claim the active ingredient of the approved drug.[2] Patents claiming solely device components of a combination product are not listable in the Orange Book.[3]

Background of the Dispute

The case arose over Teva’s ProAir® HFA, a metered-dose inhaler containing albuterol sulfate, a medication used to treat bronchospasm.[4] Teva had listed nine non-expired patents in the FDA’s Orange Book relating to the ProAir® HFA.[5] The five asserted patents claim physical components of an inhaler, and not the active ingredient (albuterol sulfate).[6]

When Amneal filed an Abbreviated New Drug Application (ANDA) with a paragraph IV certification, Teva sued Amneal for patent infringement under the Hatch-Waxman Act.[7] In response, Amneal filed several counterclaims, including a claim seeking an order requiring Teva to delist the five asserted patents from the Orange Book.[8] The district court concluded that the asserted patents are not directed to the active ingredient—albuterol sulfate—but rather to the metered inhaler device and rejected Teva’s arguments that (1) under the Hatch-Waxman Act a patent claims a drug if the approved drug infringes the patent and (2) the asserted patents are Orange Book listable because the claimed articles are intended for use as a component of ProAir® HFA.[9] The district court ordered Teva to remove the challenged patents from the Orange Book, which the Federal Circuit has now affirmed.[10]

The Court’s Reasoning

  1. Statutory interpretation

    The Federal Circuit explained that a patent that “claims the drug for which the applicant submitted the application” in 21 U.S.C. § 355(b)(1)(A)(viii)(I) does not mean that “the claim could somehow be interpreted to read on the drug.”[11] The Federal Circuit rejected Teva’s argument that a patent claims a drug if the approved drug would infringe the patent.[12] The Federal Circuit clarified that “[w]hether Teva’s [New Drug Application (NDA}] infringes Teva’s patents is separate from the issue of whether those patents actually claim the drug for which Teva submitted the application.”[13] Moreover, the Federal Circuit noted that, contrary to Teva’s assertions, this decision aligns with earlier rulings, such as Apotex and United Food.[14] The Federal Circuit concluded that “Teva’s argument does not acknowledge that claiming and infringement have separate statutory bases and that the listing provision identifies both as separate requirements.”[15] It held that determining whether a patent is properly listed involves considerations of both claiming the drug and reasonably asserting infringement.[16] The Federal Circuit further noted that interpreting the statute provision according to Teva’s interpretation would create statutory redundancy.[17] In this case, the Federal Circuit found that Teva’s patents, which were directed to the inhaler’s device components, did not meet these statutory requirements.[18]

    1. Orange Book Listable Patents

      Turning to the issue of which patents are Orange Book listable, the Federal Circuit dismissed Teva’s argument that these patents were properly listed because they covered the ProAir® HFA device.[19] The Federal Circuit clarified that a patent must specifically claim the active ingredient or its formulation, or an approved method of using the drug, in order to be eligible for listing in the Orange Book.[20] This conclusion is based on the drug regulatory approval pathway, which focuses on the active ingredient.[21] In contrast, the Federal Circuit noted that devices have a distinct approval pathway.[22] 

      The Federal Circuit rejected Teva’s arguments that (1) this interpretation is inconsistent with the statutory definition of a drug as a component for use in an article to treat disease, and (2) its ProAir® HFA inhaler—a combination product containing both drug and device components—should allow the device-related patents to be listed in the Orange Book.[23] The Federal Circuit noted that “the fact that the FDA approved Teva’s ProAir® HFA combination product as a drug does not make the inhaler’s device parts a drug. They are still devices, just ones present in the product that was approved, in a single application, under the NDA pathway.”[24] Therefore, the Federal Circuit concluded that patent claims directed only to a product device feature, such as the inhaler’s dose counter mechanism, is insufficient.

      Lastly, The Federal Circuit dismissed Teva’s request for a remand for the district court to construe the claims of its patents, arguing that they did claim an active ingredient. [25] The Federal Circuit found no need for a Markman hearing in this instance because, even under Teva’s proposed construction, the claims of the asserted patents do not satisfy the statutory requirement of claiming the active ingredient as Teva’s proposed construction merely would require reading the presence of “an active drug” into the claims.[26]  The Court explained that a claim requiring “an active drug” is far too broad to particularly and distinctly claim the drug approved in Teva’s product.

      Implications for the Pharmaceutical Industry

      The decision is significant for both innovator and generic pharmaceutical companies. For innovator companies, the ruling serves as a reminder to carefully review which patents are included in the Orange Book to ensure compliance with the Hatch-Waxman Act’s requirements.

      For generic drug manufacturers, this decision provides an opportunity to challenge improper listings that may delay their market entry. Generic drug manufacturers may seek delisting of patents that do not directly claim the active ingredient of a drug to expedite FDA approval as part of their overall strategy for bringing their products to market.

      In 2023-2024, the Federal Trade Commission (“FTC”) sent warning letters to numerous pharmaceutical manufacturers for improper or inaccurate listings of patents in the Orange Book, and notified the FDA that it disputes more than 300 Orange Book patents listings across 20 different brand name products.  Immediately upon release of the Federal Circuit’s decision, the FTC issued the following statement:

      We are pleased the court agreed with the FTC that these improper inhaler patent listings must be wiped from the Orange Book. Removal of junk patent listings is critical to ensuring drugmakers can fairly compete to offer generic drugs at a lower price for consumers. This decision is important not only for lowering asthma inhaler costs, it also sets the stage for removal of junk listings on a range of other critical medications where junk device listings impede competition.

      The Federal Circuit’s ruling in Teva v. Amneal clarifies the requirements for Orange Book patent listings under the Hatch-Waxman framework and marks a victory for generic drug developers.  In view of the decision and the numerous patents that have been flagged by the FTC, it will be interesting to see if pharmaceutical manufacturers that are on notice will now remove patents from the Orange Book or continue to maintain their listings and await litigation or Federal enforcement actions.

      Disclaimer: The information contained in this posting does not, and is not intended to, constitute legal advice or express any opinion to be relied upon legally, for investment purposes or otherwise. If you would like to obtain legal advice relating to the subject matter addressed in this posting, please consult with us or your attorney. The information in this post is also based upon publicly available information, presents opinions, and does not represent in any way whatsoever the opinions or official positions of the entities or individuals referenced herein.

      [1] Teva Branded Pharm. Prods. R&D, Inc. v. Amneal Pharms. of New York, LLC, No. 2024-1936, 2024 WL 5176737 (Fed. Cir. Dec. 20, 2024).

      [2] Id.

      [3] Id.

      [4] Id. at 5.

      [5] Id. at 6.

      [6] Id. at *7.

      [7] Id.

      [8] Id.

      [9] Id.

      [10] Id.  As of December 23, 2024, all five of Teva’s patents that are the subject of this decision remain listed in the Orange Book.

      [11] Id. at 12.

      [12] Id. at 11.

      [13] Id.

      [14] See id. at 11-12; Apotex, Inc. v. Thompson, 347 F.3d 1335 (Fed. Cir. 2003); and United Food & Commercial Workers Local 1776 v. Takeda Pharmaceutical Co., 11 F.4th 118 (2d Cir. 2021).

      [15] Id. at 12.

      [16] Id.

      [17] Id. at 9.

      [18] Id.

      [19] Id. at 13.

      [20] Id.

      [21] Id. at 14.

      [22]  Id. at 13-14.

      [23] Id. at 15.

      [24] Id. at 16.

      [25] Id. 17.

      [26] Id.