{"id":39433,"date":"2026-08-15T09:25:00","date_gmt":"2026-08-15T13:25:00","guid":{"rendered":"https:\/\/www.drugpatentwatch.com\/blog\/?p=39433"},"modified":"2026-08-14T07:35:59","modified_gmt":"2026-08-14T11:35:59","slug":"sue-early-win-big-the-hidden-roi-of-challenging-weak-method-of-use-drug-patents","status":"publish","type":"post","link":"https:\/\/www.drugpatentwatch.com\/blog\/sue-early-win-big-the-hidden-roi-of-challenging-weak-method-of-use-drug-patents\/","title":{"rendered":"Sue Early, Win Big: The Hidden ROI of Challenging Weak Method-of-Use Drug Patents"},"content":{"rendered":"\n
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Every generic and biosimilar developer knows the standard playbook. Wait for the composition-of-matter patent to run out, clear the Orange Book, file the ANDA, launch. Method-of-use patents get treated as an afterthought, something to design around with a skinny label rather than something worth fighting. That instinct is often wrong, and it is getting more expensive to be wrong every year the FTC keeps publishing lists of “junk” patents that never should have made it into the Orange Book in the first place.<\/p>\n\n\n\n

The companies that have made real money on method-of-use patents did not wait. Mylan filed against Biogen’s Tecfidera dosing patent years before the patent’s stated expiration and knocked eight years off the exclusivity period. Acorda’s four Ampyra dosing patents fell to an obviousness challenge that generic makers could have brought the moment Acorda started layering “new” claims on top of an already-licensed compound. The pattern repeats across therapeutic areas: a weak method-of-use patent sits in the Orange Book collecting a 30-month stay’s worth of leverage, and the first company willing to spend legal money early is the one that captures the exclusivity window, the settlement terms, and the market position.<\/p>\n\n\n\n

This piece walks through what “weak” actually means in method-of-use claims, the mechanics of when and how to challenge one, five real cases that show the financial stakes, and the cost-versus-reward math that should drive the decision. DrugPatentWatch data and Orange Book filings anchor the analysis throughout, because patent strength is a factual question before it is a legal one.<\/p>\n\n\n\n

What Makes a Method-of-Use Patent Weak (And Why Originators File Them Anyway)<\/strong><\/h2>\n\n\n\n

A method-of-use patent claims a way of using a drug, not the drug molecule itself. It might cover a specific dose, a specific patient population, a specific dosing schedule, or a specific combination with another therapy. Originators file these patents because they extend commercial protection well past the point where the compound patent expires, and because the U.S. Patent and Trademark Office grants a large share of them without much scrutiny of whether the claimed method was actually novel or adequately described at filing.<\/p>\n\n\n\n

The problem for originators is that a method-of-use patent filed years after the original compound patent, often based on clinical data generated during commercialization rather than during initial drug discovery, is structurally more likely to run into two specific validity problems: the patent examiner allowed claims broader than what the specification actually supports, or the claimed method was an obvious next step once the underlying compound and its general mechanism were already public. Both problems are provable with public documents. Neither requires access to the originator’s internal files. That is what makes early challenges different from most patent litigation: the weakness is often visible in the patent’s own prosecution history before a single document request goes out.<\/p>\n\n\n\n

Method-of-Use vs. Composition-of-Matter Patents: Why the Distinction Decides Your Strategy<\/strong><\/h3>\n\n\n\n

A composition-of-matter patent claims the molecule. It is almost always the strongest patent in a drug’s portfolio because there is rarely a design-around: if the molecule is patented, a generic maker needs the identical active ingredient to get an AB-rated ANDA approval, so no amount of clever claim drafting on the generic side avoids infringement. Composition-of-matter patents are worth fighting on validity grounds, but they are hard to win against because they were usually filed early, examined thoroughly, and supported by data collected during the drug’s initial development.<\/p>\n\n\n\n

Method-of-use patents sit differently. Because they claim a use rather than a molecule, a generic company has two paths around them: challenge validity, or carve the patented use out of the label under Section viii of the Hatch-Waxman Act and market only for the unpatented indications, the so-called skinny label. Both paths are available at the same time, and the choice between them, or the decision to pursue both, is a live strategic question the moment a method-of-use patent lands in the Orange Book. That optionality is exactly why weak method-of-use patents carry outsized ROI: the challenger is not betting everything on one theory.<\/p>\n\n\n\n

The Four Most Common Weaknesses in Method-of-Use Claims<\/strong><\/h3>\n\n\n\n

Four recurring defects show up across the method-of-use patents that have fallen in litigation over the past decade. None of them require confidential discovery to spot in a first-pass diligence review.<\/p>\n\n\n\n

Lack of Written Description<\/strong><\/h4>\n\n\n\n

Section 112 of the Patent Act requires a patent’s specification to reasonably convey to a skilled reader that the inventor actually possessed the claimed invention at the time of filing. Method-of-use patents built by combining language from an earlier, broader specification with a narrower claim added later are especially exposed here. Biogen’s Tecfidera patent is the textbook example: the specification largely described one inventor’s work on identifying drug candidates generally, while the asserted claims covered a specific 480 mg\/day dosing regimen developed by a different inventor. A West Virginia federal court found the specification did not reasonably convey that the inventors possessed the specific dosing claim, and invalidated it.[2][3]<\/sup><\/p>\n\n\n\n

Obviousness Over the Base Compound or an Earlier Patent<\/strong><\/h4>\n\n\n\n

If the originator already holds a broad patent on using the compound for a related purpose, a later, narrower method claim covering a specific dose or regimen is vulnerable to an obviousness challenge, particularly if the claimed dose falls within a range a skilled clinician would have tried anyway. Acorda’s four Ampyra patents, which claimed a specific twice-daily 10 mg dosing regimen of 4-aminopyridine for improving walking in multiple sclerosis patients, fell exactly this way. The district court and, on appeal, the Federal Circuit found that a person skilled in the art would have been motivated to try that dose with a reasonable expectation of success, given what was already known from the earlier, broader Elan patent covering sustained-release 4-AP generally.[4][5][6]<\/sup><\/p>\n\n\n\n

Claims That Don’t Actually Cover a Method of Using the Drug<\/strong><\/h4>\n\n\n\n

The Orange Book only permits listing of patents that claim the drug substance, the drug product, or a method of using the drug for which approval was sought. Patents covering distribution systems, computerized risk evaluation and mitigation strategy protocols, packaging, or delivery devices frequently get listed anyway, and frequently get thrown out once a generic or 505(b)(2) challenger forces the question. Jazz Pharmaceuticals learned this with a patent covering the REMS system that controls Xyrem distribution: the Federal Circuit held it did not claim a method of using the drug at all and ordered it delisted.[13][14]<\/sup><\/p>\n\n\n\n

Dosing and Titration Patents Layered on Known Regimens<\/strong><\/h4>\n\n\n\n

A related but distinct weakness shows up in patents claiming a specific titration schedule, a specific starting dose followed by an increase, or a specific maximum dose, where the individual dosing steps were each already disclosed somewhere in the prior art even if never combined in exactly that sequence before. These claims survive prosecution because examiners often do not locate every relevant piece of prior art, but they invite the same obviousness analysis that took down Acorda’s patents, and they are frequently the last layer of protection standing once a composition-of-matter patent and any formulation patents have already expired.<\/p>\n\n\n\n

The Hatch-Waxman Clock: Where an Early Challenge Fits<\/strong><\/h2>\n\n\n\n

Timing decides most of the value in a method-of-use challenge. The Hatch-Waxman Act built a specific mechanism for resolving these disputes before generic launch rather than after, and that mechanism rewards the company that moves first.<\/p>\n\n\n\n

Paragraph IV Certification, the 30-Month Stay, and 180-Day Exclusivity, Explained<\/strong><\/h3>\n\n\n\n

When a generic company files an ANDA referencing a brand drug with Orange Book-listed patents, it must certify against each one. A Paragraph IV certification asserts that the listed patent is invalid, unenforceable, or will not be infringed by the generic product. Filing a Paragraph IV certification is itself an act of patent infringement under 35 U.S.C. \u00a7 271(e)(2), which lets the brand company sue immediately rather than waiting for an actual launch. If the brand sues within 45 days of receiving notice of the Paragraph IV certification, FDA approval of the ANDA is automatically stayed for up to 30 months or until a court rules, whichever comes first.<\/p>\n\n\n\n

The upside for the challenger is the first-to-file incentive: the first generic company to submit a substantially complete ANDA with a Paragraph IV certification against a given patent is eligible for 180 days of marketing exclusivity against all other generics, once its own product is approved. That exclusivity period, on a blockbuster drug, is frequently worth more than the entire cost of the litigation that won it. Mylan’s press materials on the Tecfidera win specifically noted its expectation of 180-day exclusivity as a first filer.[3]<\/sup><\/p>\n\n\n\n

Timeline: Filing Early vs. Filing at Year Eight of a Ten-Year Patent Life<\/strong><\/h3>\n\n\n\n

A method-of-use patent’s competitive value comes from the years remaining before it expires, not from its face value on the day it issues. Filing an early Paragraph IV challenge, meaning within the first year or two after the patent is listed rather than waiting until the year before its stated expiration, compresses the following sequence:<\/p>\n\n\n\n

    \n
  • Patent listed in Orange Book, generic files ANDA with Paragraph IV certification shortly after developing a bioequivalent product<\/li>\n\n\n\n
  • Brand sues within 45 days, triggering the 30-month stay<\/li>\n\n\n\n
  • Discovery, claim construction, and trial occur over 18 to 30 months<\/li>\n\n\n\n
  • A validity ruling for the challenger clears the path to launch well before the patent’s stated expiration date<\/li>\n<\/ul>\n\n\n\n

    Filing late compresses none of that. It simply moves the fight closer to expiration, where the brand has less incentive to settle on favorable terms because there is less time left on the patent to give away. Acorda’s own securities filings show the pattern: it kept negotiating settlements with individual generic challengers through 2018, years after the underlying obviousness weakness in its patents was arguably discoverable, and by the time the Federal Circuit affirmed invalidity, Acorda was negotiating from a position where at least two first-to-file generic companies already had tentative approval and no incentive to wait.[7][8]<\/sup><\/p>\n\n\n\n

    Why First-to-File Status Still Matters on a Patent You Expect to Beat<\/strong><\/h3>\n\n\n\n

    A common mistake is treating first-to-file exclusivity as only relevant when a challenger expects to lose and needs the settlement leverage. In practice, first-to-file status matters just as much when the challenger expects to win outright, because 180 days of exclusive generic competition against the brand, with no other generic on the market, is worth dramatically more per unit than launching into a market already crowded with five or six other first-day generics. Being early is not a hedge. It is the primary source of the return.<\/p>\n\n\n\n

    Case Study: Biogen’s Tecfidera and the Written-Description Problem Mylan Found Early<\/strong><\/h2>\n\n\n\n

    Tecfidera, Biogen’s oral multiple sclerosis treatment, generated approximately 3.78 billion dollars in US sales in the twelve months before Mylan’s district court win in June 2020.[3]<\/sup> Biogen’s remaining protection rested on U.S. Patent No. 8,399,514, covering methods of treating MS with a 480 mg\/day dose of dimethyl fumarate, a patent that was not set to expire until 2028.<\/p>\n\n\n\n

    What the ‘514 Patent Actually Claimed<\/strong><\/h3>\n\n\n\n

    Biogen’s own patent family told the story of the vulnerability. The specification underlying the ‘514 patent drew primarily from one inventor’s earlier work identifying drug candidates for neurological disorders generally, while the specific 480 mg\/day dosing claim came from a different inventor’s later contribution. Judge Irene Keeley of the Northern District of West Virginia found, after a bench trial, that Mylan had shown by clear and convincing evidence that the specification did not reasonably convey that the named inventors possessed the specific dosing invention being claimed.[2]<\/sup> That is a written-description problem, not a novelty problem, and it is the kind of defect that a careful read of the patent’s own prosecution history can surface well before litigation starts.<\/p>\n\n\n\n

    What an Eight-Year Head Start Was Worth<\/strong><\/h3>\n\n\n\n

    Mylan’s ANDA was pending on the basis of being among the first to file a substantially complete Paragraph IV certification against dimethyl fumarate, positioning it for 180 days of exclusivity once approved.[3]<\/sup> The company launched its generic in August 2020, becoming the first oral MS generic on the US market, while Biogen’s appeal was still pending. Biogen ultimately lost that appeal at the Federal Circuit in 2021 and lost a subsequent rehearing petition in 2022, over Judge Lourie’s dissent joined by Judges Moore and Newman arguing the panel had misapplied the written-description standard.[9][10]<\/sup> The net effect: a patent originally good through 2028 stopped providing exclusivity in 2020, an eight-year compression driven entirely by a challenger willing to litigate a written-description theory rather than wait out the clock.<\/p>\n\n\n\n

    \n

    “The median cost for a patent infringement lawsuit with over $25 million at risk is $3.0 million through the discovery phase alone, and rises to $5.5 million for a case that goes through the end of trial and appeal,” according to the American Intellectual Property Law Association’s biennial Report of the Economic Survey.[1]<\/sup><\/p>\n<\/blockquote>\n\n\n\n

    Set against $3.78 billion in annual US sales for the drug at stake, a $5.5 million litigation budget is a rounding error. That ratio, not the specific dollar figures, is the number worth carrying into every internal ROI discussion about whether a method-of-use patent is worth challenging.<\/p>\n\n\n\n

    Case Study: Acorda’s Ampyra and the Obviousness Trap Around an Expiring Base Patent<\/strong><\/h2>\n\n\n\n

    Ampyra, Acorda’s dalfampridine treatment for walking impairment in MS patients, accounted for nearly all of the company’s 471 million dollars in 2018 revenue.[8]<\/sup> Acorda held an exclusive license to the broader “Elan patent,” covering sustained-release 4-aminopyridine generally, alongside four of its own, narrower patents claiming the specific twice-daily 10 mg regimen actually marketed as Ampyra.<\/p>\n\n\n\n

    How the Elan Patent Made Acorda’s Later Claims Vulnerable<\/strong><\/h3>\n\n\n\n

    Roxane, Mylan, and Teva each filed ANDAs with Paragraph IV certifications and were sued by Acorda starting in July 2014. The Delaware district court found the four Acorda-specific patents invalid for obviousness, while upholding the broader Elan patent, which expired on its own terms in July 2018.[4]<\/sup> On appeal, the Federal Circuit affirmed 2-1, agreeing that a skilled person, already aware of the Elan patent’s disclosure and general MS treatment literature, would have been motivated to try the specific 10 mg twice-daily dose with a reasonable expectation that it would improve walking ability.[4][5][6]<\/sup> Judge Pauline Newman dissented, arguing the majority undervalued the decades of prior failed attempts to develop a usable 4-AP therapy, but the majority position controlled.<\/p>\n\n\n\n

    The Settlement Cascade That Followed the Obviousness Ruling<\/strong><\/h3>\n\n\n\n

    Once the district court ruling issued in 2017 and the Federal Circuit affirmed in September 2018, Acorda’s negotiating position collapsed in a matter of months. The company disclosed a settlement with Mylan permitting a generic launch by 2025 or earlier under specified conditions, while Bernstein analyst commentary at the time noted that Teva and Hikma, both classified as first-to-file challengers, already held tentative FDA approvals and had not yet settled, meaning they could launch on their own timeline rather than Acorda’s.[7][8]<\/sup> The Supreme Court denied Acorda’s certiorari petition, closing off further appeal.[7]<\/sup> The four patents were originally set to run through 2025 to 2027; the obviousness ruling effectively erased that remaining window years ahead of schedule, all because the challengers were willing to litigate a claim that, on its face, layered a specific dose on top of an already-disclosed compound.<\/p>\n\n\n\n

    Case Study: Amarin v. Hikma and the Supreme Court’s 2026 Reset of Skinny-Label Risk<\/strong><\/h2>\n\n\n\n

    Not every method-of-use fight is about invalidating the patent. Amarin’s Vascepa litigation against Hikma addressed a different question entirely: whether a generic company that carves the patented indication out of its label, following the skinny-label process Congress built specifically to avoid this kind of dispute, can still be sued for inducing infringement based on how it talks about its own product.<\/p>\n\n\n\n

    GSK v. Teva: The Precedent That Made Every Skinny Label Look Dangerous<\/strong><\/h3>\n\n\n\n

    Teva launched generic carvedilol in 2007 with a skinny label carving out GSK’s patented congestive heart failure indication, only marketing for hypertension. GSK sued for induced infringement anyway, pointing to press releases and marketing materials describing Teva’s product as the “AB rated generic equivalent” of Coreg, plus language remaining on the label itself that GSK’s experts argued would lead a physician to associate the product with the carved-out heart-failure use. A jury awarded GSK 235 million dollars in damages.[10][11]<\/sup> The Federal Circuit, in a 2-1 decision after rehearing, reinstated that verdict in 2021, finding substantial evidence supported inducement during both the skinny-label period and a later period when FDA required Teva to adopt a full label.[11][12]<\/sup> The Supreme Court denied certiorari, leaving generic manufacturers across the industry with a working assumption that a skinny label alone did not fully protect them from inducement exposure if their marketing described the product too broadly.[13]<\/sup><\/p>\n\n\n\n

    What Hikma v. Amarin Changes for Companies Weighing a Design-Around<\/strong><\/h3>\n\n\n\n

    Amarin sued Hikma over its generic icosapent ethyl, arguing that Hikma’s skinny label, which carved out Amarin’s cardiovascular-risk-reduction patents and approved only the severe hypertriglyceridemia indication, still amounted to inducement because of Hikma’s press releases, website content, and residual label language describing use alongside statins. The Federal Circuit revived Amarin’s complaint in 2024, applying the same totality-of-conduct framework it used in GSK v. Teva.[14][15][16]<\/sup> The Supreme Court granted certiorari and, in a unanimous opinion by Justice Ketanji Brown Jackson, reversed. The Court held that routine, FDA-mandated label content and ordinary references to a product as a “generic version” of the branded drug do not, by themselves, state a claim for induced infringement, and it directly criticized the Federal Circuit’s post-GSK trend of asking whether a statement could be read as encouraging infringement rather than whether the defendant actually intended to encourage it.[17][18][19]<\/sup><\/p>\n\n\n\n

    Section viii Statements Are Still Viable, Now With a Clearer Bar<\/strong><\/h4>\n\n\n\n

    For a company deciding whether to challenge a method-of-use patent’s validity outright or simply carve it out and rely on a skinny label, the Hikma decision meaningfully lowers the residual risk of the skinny-label path, at least for routine marketing conduct. It does not eliminate the risk entirely. Companies that go further than Hikma did, that explicitly reference the carved-out indication in marketing materials or leave label language that specifically tracks the patented use, remain exposed under the reasoning the Court left intact from GSK. The practical lesson for early diligence is that a skinny label plus disciplined, narrowly scoped marketing is now a more defensible position than it was between 2021 and mid-2026, which changes the relative appeal of validity litigation versus a design-around for some weak method-of-use patents.<\/p>\n\n\n\n

    Case Study: Jazz v. Avadel and the REMS Patent That Was Never a Method of Use<\/strong><\/h2>\n\n\n\n

    Jazz Pharmaceuticals markets Xyrem, a sodium oxybate treatment for narcolepsy, under an FDA-mandated risk evaluation and mitigation strategy required because of the drug’s abuse potential as a form of GHB. Jazz obtained and listed U.S. Patent No. 8,731,963, covering a computerized system for implementing that REMS, in the Orange Book against Xyrem.<\/p>\n\n\n\n

    Why Device, Packaging, and REMS Patents Are Often an Orange Book Portfolio’s Weakest Link<\/strong><\/h3>\n\n\n\n

    Avadel, developing a once-nightly oxybate formulation called Lumryz under a Section 505(b)(2) application, initially filed a Section viii statement rather than certifying against the REMS patent, on the theory that a computerized distribution-control system is not a method of using the drug at all. FDA nonetheless ordered Avadel to certify to the patent in 2022, triggering a second infringement suit and a fresh 30-month stay. Avadel counterclaimed for delisting, and the District of Delaware agreed in November 2022 that the patent did not qualify as a method of using the drug under 21 U.S.C. \u00a7 355(b) and ordered it removed from the Orange Book. The Federal Circuit affirmed unanimously in February 2023, and Jazz requested delisting within days of the ruling, clearing Avadel’s path to final approval.[20][21][22][23]<\/sup><\/p>\n\n\n\n

    The broader signal here matters beyond one narcolepsy drug: patents covering REMS systems, delivery devices, injector pens, and packaging get listed in the Orange Book regularly, and a growing body of case law, reinforced by the FTC’s own enforcement priorities discussed below, treats them as categorically weaker than patents actually claiming the drug substance or a genuine clinical method of use. A challenger doing early diligence on an Orange Book portfolio should flag every non-clinical patent for a listability challenge before spending money on a validity fight over the clinical method claims.<\/p>\n\n\n\n

    Case Study: Restasis and the Sovereign-Immunity Maneuver That Didn’t Save a Weak Portfolio<\/strong><\/h2>\n\n\n\n

    Allergan’s dry-eye treatment Restasis carried six Orange Book-listed patents facing inter partes review petitions from Mylan, Teva, and Akorn. Rather than defend the patents on the merits at the PTAB, Allergan transferred all six to the Saint Regis Mohawk Tribe in September 2017 in exchange for a 15 million dollar annual licensing fee, betting that tribal sovereign immunity would force dismissal of the pending IPRs.[24][28]<\/sup><\/p>\n\n\n\n

    What the Saint Regis Mohawk Tribe Deal Signals About Weak Patent Defense<\/strong><\/h3>\n\n\n\n

    The maneuver failed at every level. The PTAB denied the Tribe’s motion to dismiss in February 2018, holding that tribal sovereign immunity does not extend to IPR proceedings.[25][27]<\/sup> The Federal Circuit affirmed in July 2018, reasoning that an IPR functions more like an agency enforcement action than a private civil suit, a category tribal immunity does not reach.[26]<\/sup> The Supreme Court declined to hear a further appeal. Separately, in Hatch-Waxman litigation over the same patents running in parallel, Judge William Bryson in the Eastern District of Texas invalidated four of the patents as obvious, and the PTAB itself subsequently found additional Restasis claims unpatentable once the IPRs proceeded on the merits.[29][24]<\/sup><\/p>\n\n\n\n

    The lesson for anyone evaluating a method-of-use portfolio is not really about tribal sovereign immunity, which the Federal Circuit closed off as a strategy in 2018. It is that a company’s willingness to pursue an unconventional legal maneuver to avoid a validity challenge is itself a signal about how confident that company is in the underlying patent. Allergan spent significant licensing fees and litigation costs on the sovereign-immunity structure specifically because straightforward validity defense looked unfavorable, and the patents were, in fact, invalidated on the merits shortly after. Early challengers who track unusual defensive maneuvers, corporate patent transfers, unusual assignment structures, or aggressive settlement offers made before any ruling issues, are picking up a signal that other market participants can also read.<\/p>\n\n\n\n

    Case Study: Novartis’ Gilenya and the Negative Claim Limitation That Took Five Years and a Supreme Court Petition to Resolve<\/strong><\/h2>\n\n\n\n

    Not every early challenge resolves as cleanly as Tecfidera or Ampyra, and Gilenya is the case worth studying for what a drawn-out fight actually looks like. Novartis sued HEC Pharm and a group of other ANDA filers in 2018 over U.S. Patent No. 9,187,405, covering methods of treating relapsing-remitting multiple sclerosis with a 0.5 mg daily dose of fingolimod, sold as Gilenya, without an immediately preceding loading dose. HEC was the only defendant that chose to litigate the patent to judgment rather than settle for an agreed later launch date, and that decision took roughly five years to pay off.<\/p>\n\n\n\n

    The 0.5 mg “Absent a Loading Dose” Limitation and Why It Was Added During Prosecution<\/strong><\/h3>\n\n\n\n

    The negative claim limitation at the center of the dispute, requiring the dose be administered without a preceding loading dose, was added to the claims during patent prosecution specifically to overcome prior art the examiner had cited. The problem, as HEC argued and eventually won on, was that the 2006 specification underlying the patent never actually discussed loading doses at all, meaning there was nothing in the original filing that reasonably conveyed the inventors possessed the idea of treating patients without one. The district court initially rejected that argument after a bench trial in 2020 and granted Novartis a permanent injunction. A three-judge Federal Circuit panel upheld that result in January 2022. Then Judge Kathleen O’Malley, who had authored the original majority opinion, retired from the court, and her replacement on a subsequent rehearing panel joined a new majority that reversed course entirely in June 2022, finding the district court had clearly erred and that the specification’s silence on loading doses could not support the negative limitation.[37][38][39]<\/sup><\/p>\n\n\n\n

    Why an Early Challenge Still Took Five Years, and Why HEC Filed Anyway<\/strong><\/h3>\n\n\n\n

    Novartis, facing the prospect of losing exclusivity on a drug that generated close to 2.8 billion dollars in annual sales at the time, took the unusual step of seeking emergency relief directly from the Supreme Court. Chief Justice Roberts granted a temporary stay of the Federal Circuit’s mandate in late September 2022, briefly blocking generic launches that had been cleared to begin October 4, before the full Court lifted that stay days later and allowed generics from HEC, Dr. Reddy’s, Mylan, Torrent, Aurobindo, and others to proceed.[40][41][42]<\/sup> Novartis petitioned for full certiorari, and the Supreme Court declined to hear the case in April 2023, letting the invalidity ruling stand. Novartis’ own year-end reporting showed US Gilenya sales falling 19 percent to 1.1 billion dollars in 2022, a decline the company attributed in part to the generic entry the litigation had finally permitted.[43][44]<\/sup><\/p>\n\n\n\n

    The lesson is not that early challenges always move quickly. HEC’s fight ran from the original 2018 suit through an April 2023 cert denial, on top of earlier PTAB proceedings on the same fingolimod patent family that predated the district court case entirely.[44]<\/sup> The lesson is that HEC filed and litigated a written-description theory it believed in while every other generic company in the case settled for a later, agreed launch date rather than risk the fight. Only the company willing to litigate the weak claim actually captured the early entry when the claim was eventually confirmed invalid, and it did so years ahead of the other settling generics’ agreed dates. Patience and a willingness to litigate through a reversal are part of the cost-benefit calculation on a weak method-of-use patent, not just the initial decision to file.<\/p>\n\n\n\n

    PTAB Inter Partes Review vs. Paragraph IV Litigation: Cost, Speed, and Fit Compared<\/strong><\/h2>\n\n\n\n

    A weak method-of-use patent can be attacked through two largely independent tracks: an ANDA challenge in district court under the Hatch-Waxman framework, or an inter partes review petition at the Patent Trial and Appeal Board. They are not mutually exclusive, and a well-resourced challenger frequently runs both at once, since a PTAB decision does not require an ANDA to already be filed and can proceed on a faster statutory clock.<\/p>\n\n\n\n

    Table: IPR at the PTAB vs. ANDA Litigation in District Court<\/strong><\/h3>\n\n\n\n
    Factor<\/th>PTAB Inter Partes Review<\/th>Hatch-Waxman ANDA Litigation<\/th><\/tr><\/thead>
    Who can file<\/td>Any party, no ANDA required<\/td>Only an ANDA filer certifying against the patent<\/td><\/tr>
    Available invalidity grounds<\/td>Anticipation and obviousness only, based on patents and printed publications<\/td>All invalidity grounds, including written description, enablement, and obviousness<\/td><\/tr>
    Statutory decision clock<\/td>Final written decision within 12 months of institution (18 with extension)<\/td>No fixed clock; the 30-month stay is a ceiling, not a target<\/td><\/tr>
    Typical cost through final decision<\/td>Generally lower than district court litigation on a comparable patent<\/td>Median around 5 million dollars for cases with significant value at risk, per AIPLA survey data[1]<\/sup><\/td><\/tr>
    Effect of a challenger win<\/td>Patent claims cancelled for all purposes, against all parties<\/td>Clears the specific litigant’s ANDA to proceed; may or may not resolve claims against other filers<\/td><\/tr>
    180-day exclusivity impact<\/td>None directly; IPR does not itself trigger first-to-file exclusivity<\/td>Directly tied to Paragraph IV filing and case outcome<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    When an IPR Petition Beats (or Complements) an ANDA Challenge<\/strong><\/h3>\n\n\n\n

    An IPR petition is generally the faster and cheaper route to attack written-description or obviousness weaknesses of the type that took down the Tecfidera and Ampyra patents, and it can be filed by a party that has not yet completed ANDA development work, which matters when a challenger wants to test patent strength before committing to full-scale bioequivalence studies. The tradeoff is that IPR estoppel can bar the same party from raising the same invalidity grounds again in district court once a final written decision issues, so the choice of forum and timing needs to account for whether the challenger expects to also need the district court’s broader remedies, including a judgment that clears the ANDA for approval outright. Biogen’s own securities filings note that Mylan pursued an IPR against the ‘514 patent in parallel with the district court case, and while the PTAB upheld the patent’s patentability in February 2020, the district court reached the opposite conclusion on a written-description theory the PTAB was not statutorily positioned to consider.[2]<\/sup> Running both tracks meant a single unfavorable PTAB result did not end the campaign.<\/p>\n\n\n\n

    The ROI Math: What an Early Challenge Costs vs. What It Is Worth<\/strong><\/h2>\n\n\n\n

    The strategic case for early challenges only holds up if the numbers do. Fortunately, the inputs are public enough to model with reasonable confidence before committing legal spend.<\/p>\n\n\n\n

    What Hatch-Waxman Litigation Actually Costs, by the Numbers<\/strong><\/h3>\n\n\n\n

    AIPLA’s biennial Report of the Economic Survey remains the most cited industry benchmark. For cases with more than 25 million dollars at risk, a bracket that essentially every branded pharmaceutical dispute falls into, median litigation cost runs about 3.0 million dollars through the end of discovery and 5.5 million dollars through trial and appeal.[1]<\/sup> Hatch-Waxman litigation specifically tends to land at the higher end of that range given the technical complexity of pharmacokinetic and formulation evidence, with median costs cited around 5 million dollars for cases carrying substantial value.[1]<\/sup> For cases where between 1 million and 10 million dollars is at risk, the median drops to roughly 2.0 million dollars total.[1]<\/sup> IPR petitions typically run below district court litigation costs, though they still require substantial expert and attorney time given the technical density of pharmaceutical prior art.<\/p>\n\n\n\n

    Modeling the Exclusivity Prize: 180 Days of First-to-File Revenue<\/strong><\/h3>\n\n\n\n

    The other side of the ledger is the value of the exclusivity window a successful early challenge unlocks. A rough model: take the brand’s annual US net sales for the molecule, apply a typical first-to-file generic price discount, usually 20 to 40 percent off brand pricing before additional entrants arrive, and prorate for 180 days. On a drug generating even a few hundred million dollars in annual US sales, that math produces tens of millions of dollars in exclusive-period revenue, against a litigation cost in the single-digit millions. On a drug the size of Tecfidera, at 3.78 billion dollars in trailing annual sales, the exclusivity value dwarfs the litigation budget by two orders of magnitude.[3]<\/sup><\/p>\n\n\n\n

    A Simple Framework for Estimating Challenge ROI<\/strong><\/h4>\n\n\n\n

    A workable internal framework runs through four questions before committing budget to a challenge: how many years remain on the patent if the challenge is not brought, what is the brand’s current annual US net sales for the molecule, what generic price discount and market share is realistic during a 180-day exclusive period versus a crowded multi-generic period after, and what is the estimated litigation cost given the complexity of the specific invalidity theory being pursued. Running those four inputs through even a conservative model, discounting for litigation risk, typically shows a positive expected value whenever a weak method-of-use patent is protecting more than roughly 100 million dollars in annual US sales, well below the scale of most of the drugs discussed in this piece.<\/p>\n\n\n\n

    Where the ROI Math Breaks Down<\/strong><\/h4>\n\n\n\n

    The model fails in a few predictable situations. A patent protecting a low-revenue niche drug rarely justifies the litigation spend regardless of how weak the claims look on paper. A patent with only one or two years remaining before natural expiration compresses the exclusivity prize enough that litigation costs can exceed the benefit, particularly once appeal timelines are factored in. And a patent that appears weak on validity grounds but where the challenger’s own product cannot achieve bioequivalence approval on a competitive timeline anyway makes the entire exercise moot, since a validity win with no approved ANDA behind it captures nothing.<\/p>\n\n\n\n

    The FTC’s Orange Book Crackdown and What It Means for Challengers<\/strong><\/h2>\n\n\n\n

    Since September 2023, the Federal Trade Commission has run an active campaign against improperly listed Orange Book patents, and its target list reads almost like a checklist of the weak-patent categories discussed throughout this piece.<\/p>\n\n\n\n

    Which Patent Types the FTC Has Targeted So Far<\/strong><\/h3>\n\n\n\n

    The FTC’s first round of warning letters, sent to 10 manufacturers in November 2023, challenged more than 100 patents across 13 inhaler products and 4 epinephrine autoinjector products as improperly or inaccurately listed.[30][31]<\/sup> A second round in April 2024 expanded the challenge to more than 300 additional patents across 20 branded products, including diabetes and weight-loss injector-pen patents covering products like Novo Nordisk’s Ozempic, plus additional asthma and COPD inhaler patents.[32][33]<\/sup> In response to the first round, several manufacturers voluntarily delisted 14 patents across 6 NDAs.[34]<\/sup> The second round saw far less voluntary compliance, prompting the FTC to renew its challenge in May 2025 against more than 200 listings that manufacturers had recertified rather than delisted, this time backed by a Federal Circuit ruling affirming that Teva had been ordered to delist several of its own asthma inhaler patents as improperly listed, consistent with an amicus brief the FTC had filed in that case.[35]<\/sup><\/p>\n\n\n\n

    Drug-Device Combination Patents<\/strong><\/h4>\n\n\n\n

    Inhaler, autoinjector, and injector-pen patents make up the bulk of the FTC’s target list because these patents frequently claim the delivery device rather than the drug substance or product itself, the same category of defect that doomed Jazz’s REMS patent in the Avadel case. FTC’s Bureau of Competition has stated directly that only patents claiming the active ingredient should be listed, and that device patents not claiming the active ingredient should not be.[36]<\/sup><\/p>\n\n\n\n

    REMS and Distribution System Patents<\/strong><\/h4>\n\n\n\n

    The Federal Circuit’s Jazz v. Avadel ruling gave the FTC a precedent it has since leaned on, and REMS-type patents remain a recurring category in the agency’s ongoing scrutiny, since a computerized access-control system is not, under the statute, a method of using the drug for which approval was sought.[20]<\/sup><\/p>\n\n\n\n

    What Delisting Success Rates Tell You About Patent Strength<\/strong><\/h3>\n\n\n\n

    The uneven response to the FTC’s two rounds of letters is itself useful diligence data. Manufacturers who delisted patents after the first round effectively conceded those listings were indefensible rather than risk an adverse court ruling and the associated antitrust exposure under Section 5 of the FTC Act.[30]<\/sup> Manufacturers who instead recertified their patents as properly listed are signaling either genuine confidence or a bet that the FTC would not follow through with litigation, a bet that looked worse after the Federal Circuit’s Teva ruling.[35]<\/sup> A challenger running early diligence on any drug-device combination product should treat FTC dispute-letter status, publicly available through FDA’s patent listing dispute database, as a starting point rather than an afterthought.<\/p>\n\n\n\n

    What Happens If You Wait Instead of Challenging Early<\/strong><\/h2>\n\n\n\n

    The cost of delay is not symmetric. Every year a weak method-of-use patent goes unchallenged, the brand company’s negotiating position, the available settlement terms, and the exclusivity prize all move in the wrong direction for the challenger.<\/p>\n\n\n\n

    Settlement Leverage Erodes as Launch Approaches<\/strong><\/h3>\n\n\n\n

    Acorda’s settlement history illustrates the dynamic clearly. Once the obviousness ruling against its four patents was affirmed, the company negotiated settlement terms with individual generic filers on a rolling basis, and those terms varied depending on how close each generic company already was to an independent launch. Companies with tentative approval and no remaining settlement need, like Teva and Hikma per contemporaneous analyst commentary, had far more leverage in 2018 than they would have had years earlier when Acorda still controlled meaningful uncertainty about the outcome.[7][8]<\/sup> A challenger who waits until a patent’s final years to bring a validity fight gives up years of exclusivity value even in a winning scenario, because the exclusivity clock only starts running once a favorable ruling clears the ANDA, and there is less runway left on the patent to give away.<\/p>\n\n\n\n

    A Late Skinny Label Doesn’t Fully Insulate You From Inducement Risk<\/strong><\/h3>\n\n\n\n

    For companies planning to rely on a skinny label rather than a validity challenge, waiting carries a different risk. The GSK v. Teva verdict shows that inducement liability can attach years after a skinny-label launch, based on marketing conduct that accumulates over that entire period, not just conduct at launch. Teva’s exposure covered both the skinny-label period and a later full-label period, and the jury verdict reflected damages across both.[10][11]<\/sup> A company that launches early under a skinny label and maintains disciplined marketing throughout, consistent with the standard the Supreme Court articulated in Hikma v. Amarin, is in a materially stronger position than one that launches late and has less time to build a clean marketing record before any dispute arises.[17][18]<\/sup><\/p>\n\n\n\n

    Building the Business Case Internally<\/strong><\/h2>\n\n\n\n

    None of the analysis above matters if legal and commercial teams cannot agree internally on whether a specific method-of-use patent is worth challenging. That agreement requires a shared, factual starting point.<\/p>\n\n\n\n

    What to Pull From Orange Book and Litigation Data Before You File<\/strong><\/h3>\n\n\n\n

    A useful pre-filing diligence package covers four categories: the patent’s full prosecution history, looking specifically for claims added or broadened late in prosecution relative to the original specification, since that pattern correlates with written-description exposure; the patent family’s relationship to any earlier, broader patents covering the same compound or mechanism, since that relationship is what created the obviousness exposure in the Acorda case; whether the patent claims the drug substance, drug product, or an actual clinical method of use, versus a device, packaging, or distribution system, given the Jazz v. Avadel and FTC precedent on listability; and whether the patent or its owner has already drawn FTC dispute-letter attention or unusual defensive maneuvers, both of which are public signals of perceived weakness.<\/p>\n\n\n\n

    Where DrugPatentWatch Fits Into Early Diligence<\/strong><\/h4>\n\n\n\n

    Compiling that four-part picture manually across dozens of Orange Book entries, prosecution histories, and litigation dockets is the kind of work that patent intelligence platforms like DrugPatentWatch exist to accelerate, aggregating Orange Book listings, patent expiration data, and litigation history in a format built for exactly this kind of early screening rather than after-the-fact research once a competitor has already launched. Teams running a portfolio-wide review of which method-of-use patents are worth challenging benefit from starting with structured data rather than assembling prosecution histories one patent at a time.<\/p>\n\n\n\n

    Questions to Ask Before Committing Legal Spend<\/strong><\/h3>\n\n\n\n

    Before authorizing a validity challenge, a commercial and legal team working together should be able to answer each of the following without hedging: what specific invalidity theory applies to this patent and which of the four common weaknesses does it match, what is the realistic timeline to a ruling given the forum chosen, what does the ROI framework outlined above produce using the brand’s actual current sales figures, and what happens to the company’s competitive position if the challenge fails outright, since a lost validity fight does not just waste the litigation budget, it can also affect settlement leverage on every other patent in the same portfolio.<\/p>\n\n\n\n

    What This Means for Originators Defending Method-of-Use Patents<\/strong><\/h2>\n\n\n\n

    The same fact pattern that creates opportunity for challengers creates exposure for originators, and the lessons run in both directions.<\/p>\n\n\n\n

    Shoring Up Written Description Before Litigation, Not During It<\/strong><\/h3>\n\n\n\n

    Biogen’s loss traces directly back to how the ‘514 patent’s specification was assembled during prosecution, years before Mylan ever filed an ANDA. Originators building a method-of-use patent estate around dosing data generated during commercialization, rather than during initial development, should have outside counsel specifically test whether the specification actually supports the claims being sought, independent of whether the examiner raised the issue, since examiner silence on a written-description problem does not mean the problem does not exist. That review is inexpensive relative to the cost of losing a written-description fight after a patent has already been relied on for years of commercial planning.<\/p>\n\n\n\n

    When to Settle Early Instead of Defending a Patent You Suspect Is Weak<\/strong><\/h3>\n\n\n\n

    Allergan’s Restasis experience is a useful cautionary example in the other direction. Pursuing an unconventional defense, in that case the tribal sovereign-immunity transfer, on a patent the company may have internally recognized as vulnerable, consumed significant licensing and litigation cost and ultimately failed both procedurally and on the merits.[24][26][29]<\/sup> Originators facing an early Paragraph IV or IPR challenge against a patent with genuine written-description or obviousness exposure are often better served negotiating a settlement that preserves partial exclusivity, rather than litigating to a ruling that establishes invalidity as a matter of public record and removes all future negotiating leverage against every other generic filer waiting behind the first challenger.<\/p>\n\n\n\n

    Key Takeaways<\/strong><\/h2>\n\n\n\n
      \n
    • Method-of-use patents fail most often for written description, obviousness over an earlier broader patent, or claiming something other than an actual clinical method of use.<\/li>\n\n\n\n
    • Biogen’s Tecfidera patent lost eight years of exclusivity to a written-description challenge Mylan brought years before the patent’s stated 2028 expiration.<\/li>\n\n\n\n
    • Acorda’s four Ampyra dosing patents fell to obviousness because they layered a specific dose on top of an already-licensed, broader compound patent.<\/li>\n\n\n\n
    • The Supreme Court’s 2026 ruling in Hikma v. Amarin narrows inducement exposure for disciplined skinny-label marketing, making the design-around path more viable than it was under GSK v. Teva.<\/li>\n\n\n\n
    • Non-clinical patents, REMS systems, delivery devices, and packaging, are consistently the weakest listings in an Orange Book portfolio, as both Jazz v. Avadel and the FTC’s ongoing crackdown demonstrate.<\/li>\n\n\n\n
    • AIPLA survey data puts median Hatch-Waxman litigation cost around 5 million dollars, a figure that is dwarfed by the value of 180 days of first-to-file exclusivity on any drug with meaningful US sales.<\/li>\n\n\n\n
    • Waiting to challenge erodes settlement leverage and compresses the exclusivity window even in a winning scenario, since the clock only starts once a ruling clears the ANDA.<\/li>\n<\/ul>\n\n\n\n

      Frequently Asked Questions<\/strong><\/h2>\n\n\n\n

      What is a method-of-use patent in pharmaceuticals?<\/strong><\/h3>\n\n\n\n

      A method-of-use patent claims a specific way of using an already-known drug, such as a particular dose, dosing schedule, patient population, or combination therapy, rather than claiming the drug molecule itself.<\/p>\n\n\n\n

      How is a method-of-use patent different from a composition-of-matter patent?<\/strong><\/h3>\n\n\n\n

      A composition-of-matter patent claims the molecule directly and generally cannot be designed around. A method-of-use patent claims a use of the molecule, which means a generic company can potentially avoid infringement entirely with a skinny label carving out the patented use, in addition to challenging the patent’s validity.<\/p>\n\n\n\n

      What does it cost to challenge a weak method-of-use patent?<\/strong><\/h3>\n\n\n\n

      AIPLA survey data puts median Hatch-Waxman litigation costs around 5 million dollars for cases with substantial value at risk, with IPR petitions at the PTAB typically running lower than full district court litigation.[1]<\/sup><\/p>\n\n\n\n

      What is 180-day first-to-file exclusivity?<\/strong><\/h3>\n\n\n\n

      It is a period during which the FDA will not approve any other generic ANDA for the same drug, reserved for the first generic company to file a substantially complete ANDA with a Paragraph IV certification against a given patent, once that company’s product receives approval.<\/p>\n\n\n\n

      Can a generic company challenge a method-of-use patent without launching at risk?<\/strong><\/h3>\n\n\n\n

      Yes. A Paragraph IV certification triggers litigation without requiring the generic to launch its product before a court ruling, and an IPR petition at the PTAB can be filed independent of any ANDA filing at all.<\/p>\n\n\n\n

      What happened in Hikma v. Amarin at the Supreme Court?<\/strong><\/h3>\n\n\n\n

      In 2026, the Supreme Court unanimously held that a generic manufacturer’s FDA-compliant skinny label, combined with routine marketing statements describing the product as a generic version of the brand, does not by itself state a claim for induced infringement, narrowing the standard the Federal Circuit had applied since GSK v. Teva.[17][18][19]<\/sup><\/p>\n\n\n\n

      Why does the FTC care about Orange Book patent listings?<\/strong><\/h3>\n\n\n\n

      The FTC has taken the position that listing patents that do not properly claim the drug substance, drug product, or an approved method of use, such as device or REMS patents, can delay generic competition and violate Section 5 of the FTC Act as an unfair method of competition.[30][36]<\/sup><\/p>\n\n\n\n

      What is the most common reason method-of-use patents get invalidated?<\/strong><\/h3>\n\n\n\n

      Written description problems and obviousness over an earlier, broader patent covering the same compound are the two most common grounds, based on the pattern seen in the Tecfidera and Ampyra cases.[2][4]<\/sup><\/p>\n\n\n\n

      Does an IPR loss at the PTAB end a company’s ability to challenge a patent in district court?<\/strong><\/h3>\n\n\n\n

      Not automatically, though IPR estoppel can bar the same party from raising the same grounds again once a final written decision issues. Different invalidity theories, such as written description, which IPR proceedings cannot address since they are limited to anticipation and obviousness based on patents and printed publications, remain available in district court regardless of an IPR outcome.<\/p>\n\n\n\n

      How can a company screen an Orange Book portfolio for weak method-of-use patents before committing to litigation?<\/strong><\/h3>\n\n\n\n

      A structured review of each patent’s prosecution history, its relationship to earlier broader patents on the same compound, whether it actually claims a clinical method of use versus a device or system, and any public FTC dispute-letter or delisting activity, is the standard four-part starting point, and patent data platforms such as DrugPatentWatch are built to compile that picture across a portfolio efficiently.<\/p>\n\n\n\n

      References<\/strong><\/h2>\n\n\n\n

      [1] DrugPatentWatch. (2026). The Cost of Combat: Deconstructing Drug Patent Litigation in the Pharmaceutical Age<\/em>. Citing AIPLA Report of the Economic Survey.
      [2] Biogen International GmbH v. Mylan Pharmaceuticals Inc., No. 1:17-cv-116 (N.D. W. Va. June 18, 2020).
      [3] Mylan N.V. (2020, June 18). Mylan Wins District Court Decision Against Biogen’s Tecfidera Patent<\/em>. PR Newswire.
      [4] Acorda Therapeutics, Inc. v. Roxane Laboratories, Inc., 903 F.3d 1310 (Fed. Cir. 2018).
      [5] Mealey’s. (2018, September 11). Acorda Multiple Sclerosis Drug Patents Are Invalid, Federal Circuit Affirms<\/em>.
      [6] Patent Docs. (2018). Acorda Therapeutics, Inc. v. Roxane Laboratories, Inc. (Fed. Cir. 2018)<\/em>.
      [7] MultipleSclerosisNewsToday.com. US Supreme Court Denies Acorda Appeal on Ampyra Patents<\/em>.
      [8] BioPharma Dive. (2018, September 10). Federal court rules Ampyra patents invalid, sinking Acorda stock<\/em>.
      [9] Haug Partners. Federal Circuit Denies Rehearing in Biogen v. Mylan<\/em>.
      [10] Marshall, Gerstein & Borun. GSK v Teva: Federal Circuit Reinstates $236 Million Verdict<\/em>.
      [11] Proskauer Rose LLP. GSK v. Teva: Federal Circuit Issues New Opinion Analyzing Induced Infringement<\/em>.
      [12] Cooley LLP. (2021). GSK v. Teva: Federal Circuit Opinion After Rehearing Confirms Induced Infringement Liability Despite Skinny Label<\/em>.
      [13] Hogan Lovells. (2023). SCOTUS Won’t Hear Teva v. GSK: Where Does That Leave Us on FDA Labeling Carve-Outs?<\/em>
      [14] Duane Morris LLP. Federal Circuit Revives Induced Infringement Suit Against Generic Pharma When Its Skinny Label Is Skinny Enough<\/em>.
      [15] Hogan Lovells. (2026). Supreme Court Takes Up Hikma v. Amarin: A Pivotal Test for Skinny Labeling<\/em>.
      [16] Mondaq. (2026). High Court’s ‘Skinny Label’ Case May Tackle Wider Questions<\/em>.
      [17] Fenwick & West LLP. (2026). Supreme Court Clarifies ‘Skinny Label’ Induced Infringement Standard, Backing Generic Drugmakers<\/em>.
      [18] Foley Hoag LLP. (2026). Hikma v. Amarin: It’s Not Just About Skinny Labels<\/em>.
      [19] Legal Information Institute, Cornell Law School. Hikma Pharmaceuticals USA Inc. v. Amarin Pharma, Inc.<\/em>
      [20] Wilson Sonsini Goodrich & Rosati. (2023). Federal Circuit Affirms Jazz Pharmaceutical’s Risk Evaluation and Mitigation Strategy Patent Is Not Listable in Orange Book<\/em>.
      [21] Avadel Pharmaceuticals plc. (2023, March 2). Avadel Pharmaceuticals Requests Final FDA Approval for LUMRYZ<\/em>.
      [22] Food and Drug Law Institute. (2023). Jazz Pharmaceuticals, Inc. v. Avadel CNS Pharmaceuticals, LLC<\/em>.
      [23] Jazz Pharmaceuticals plc. (2024). Form 10-Q, quarter ended March 2024. U.S. Securities and Exchange Commission.
      [24] Center for Biosimilars. PTAB Denies Tribe’s Request for Sovereign Immunity From IPRs on Restasis Patents<\/em>.
      [25] Law360. (2018, February 23). Tribe Not Immune From Restasis IP Challenges, PTAB Says<\/em>.
      [26] Foley Hoag LLP. (2018). Federal Circuit Nixes PTAB Sovereign Immunity for Saint Regis Mohawk Tribe<\/em>.
      [27] Congressional Research Service. All Eyes on Allergan<\/em>. Legal Sidebar LSB10010.
      [28] Saint Regis Mohawk Tribe. (2017, September 8). Allergan and Saint Regis Mohawk Tribe Announce Agreements Regarding Restasis Patents<\/em>.
      [29] Sterne, Kessler, Goldstein & Fox. PTAB Cuts Down Two More Allergan Restasis Patents<\/em>.
      [30] Federal Trade Commission. (2023, November 7). FTC Challenges More Than 100 Patents as Improperly Listed in the FDA’s Orange Book<\/em>.
      [31] Wilson Sonsini Goodrich & Rosati. (2023). FTC Disputes Patent Listings of 10 Brand Drug Makers as Improperly Listed in FDA’s Orange Book<\/em>.
      [32] Federal Trade Commission. (2024, April 30). FTC Expands Patent Listing Challenges, Targeting More Than 300 Junk Listings for Diabetes, Weight Loss, Asthma and COPD Drugs<\/em>.
      [33] Mayer Brown LLP. (2024). US FTC Continues Aggressive Scrutiny of Pharmaceutical Patents Listed in the Orange Book<\/em>.
      [34] Crowell & Moring LLP. (2024). The FTC Strikes Out: Drug Manufacturers Refuse to Play Ball and Delist Orange Book Patents in Response to FTC Warning Letters<\/em>.
      [35] Federal Trade Commission. (2025, May). FTC Renews Challenge of More Than 200 Improper Patent Listings<\/em>.
      [36] American Action Forum. (2024). Primer: FTC Scrutinizes Orange Book Listings<\/em>.
      [37] Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc., No. 21-1070 (Fed. Cir. Jan. 4, 2022).
      [38] Novartis Pharmaceuticals Corp. v. HEC Pharm Co., 38 F.4th 1013 (Fed. Cir. June 21, 2022) (rehearing decision).
      [39] Patent Docs. (2022). Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc. (Fed. Cir. 2022)<\/em>.
      [40] IP Update, McDermott Will & Emery. (2022). Hold That Generic, Please: Supreme Court Grants Emergency Request to Stay Federal Circuit’s Mandate<\/em>.
      [41] pharmaphorum. (2022, October). Novartis Facing Gilenya Generics Again as Supreme Court Lifts Stay<\/em>.
      [42] FiercePharma. (2022, October 14). Novartis’ Blockbuster Gilenya Exposed to Generics in Short Term Amid Supreme Court Appeal<\/em>.
      [43] Reuters. (2023, April 17). US Supreme Court Rebuffs Novartis Bid to Revive MS Drug Gilenya Patent<\/em>.
      [44] Supreme Court of the United States. (2023). Brief in Opposition, Novartis Pharmaceuticals Corp. v. HEC Pharm Co.<\/em>, No. 22-671.<\/p>\n","protected":false},"excerpt":{"rendered":"

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