{"id":39541,"date":"2026-09-03T10:33:00","date_gmt":"2026-09-03T14:33:00","guid":{"rendered":"https:\/\/www.drugpatentwatch.com\/blog\/?p=39541"},"modified":"2026-08-26T23:34:17","modified_gmt":"2026-08-27T03:34:17","slug":"stop-tracking-drug-patents-start-tracking-who-controls-them","status":"publish","type":"post","link":"https:\/\/www.drugpatentwatch.com\/blog\/stop-tracking-drug-patents-start-tracking-who-controls-them\/","title":{"rendered":"Stop Tracking Drug Patents. Start Tracking Who Controls Them."},"content":{"rendered":"\n
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On May 1, 2026, the company that made OxyContin stopped existing. Purdue Pharma dissolved and its pharmaceutical business restarted as Knoa Pharma LLC, a new entity owned by a nonprofit foundation that is itself owned, through a holding company, by the National Opioid Abatement Trust and a separate Tribe Trust [1]. Not one claim in a single OxyContin patent changed during that transition. The chemistry did not change. The formulation did not change. What changed was who stands behind the patents when someone infringes them, who collects the money they still generate, and who decides how the portfolio gets used going forward.<\/p>\n\n\n\n

That is the gap this piece is about. A patent database tells you a patent exists, when it expires, and who is listed as the assignee of record. None of that tells you who actually controls the asset today, because control moves through channels a patent number never captures: mergers, antitrust-driven carve-outs, bankruptcy, corporate spin-offs, and royalty monetization deals that separate legal title from economic interest. Static patent lists miss all of it. A control map catches it.<\/p>\n\n\n\n

The Short Answer<\/strong><\/h2>\n\n\n\n

A drug’s patent status is not one fact. It is at least four separate facts that can each be held by a different party: who holds legal title (the assignee of record at the USPTO), who holds the economic interest (the royalty owner), who holds enforcement rights (the party with standing to sue), and who holds the regulatory position (the FDA-listed NDA or BLA holder). These four can diverge, and when they do, a patent list that only tracks expiration dates misses the part of the story that actually determines who calls the shots.<\/p>\n\n\n\n

The Findings That Matter<\/strong><\/h2>\n\n\n\n
    \n
  1. Bristol Myers Squibb’s $74 billion acquisition of Celgene, which closed November 20, 2019, required Celgene to sell Otezla’s entire global patent and product portfolio to Amgen for $13.4 billion as a condition of FTC clearance, meaning one merger routed one company’s patents to the acquirer and a second company’s patents to a party that was not part of the deal at all [2][3].<\/li>\n\n\n\n
  2. AstraZeneca paid Roche’s Chugai Pharmaceutical $775 million in 2022 to end a patent fight over Ultomiris that started under Alexion’s ownership in 2016, five years before AstraZeneca’s $39 billion acquisition of Alexion closed, showing that acquiring a patent portfolio also means acquiring its unresolved litigation exposure [4][5].<\/li>\n\n\n\n
  3. Allergan transferred six Restasis patents to the Saint Regis Mohawk Tribe on September 8, 2017 for a $13.75 million upfront payment plus royalties of up to $15 million a year, and the Federal Circuit ruled on July 20, 2018 that the transfer did not shield the patents from inter partes review, a ruling the Supreme Court left standing in April 2019 [6][7].<\/li>\n\n\n\n
  4. Purdue Pharma’s Chapter 11 case ran six years and seven months, from its September 15, 2019 filing to its April 1, 2026 plan effective date, and produced a Supreme Court ruling (Harrington v. Purdue Pharma, June 27, 2024) that voided the first settlement structure entirely, meaning the ultimate owner of the OxyContin patent estate was legally undetermined for most of that period [8][1].<\/li>\n\n\n\n
  5. Teva’s $40.5 billion acquisition of Allergan’s Actavis Generics business, completed August 2, 2016, could only close after Teva divested 79 separate generic drug businesses to five different companies (Dr. Reddy’s, Aurobindo Pharma, Cipla, Mayne Pharma, and 3M) at the FTC’s direction, which means the identity of the ANDA holder and Paragraph IV litigant on dozens of pending challenges changed as a side effect of a single antitrust settlement [9].<\/li>\n\n\n\n
  6. Reassignment records filed with the USPTO grew from fewer than 2,000 a year in 1980 to nearly 90,000 a year by 2003, according to a 2012 academic comment submitted to the agency, and the same comment cited FTC testimony finding that patent office records provide weak notice of who currently owns a patent [10].<\/li>\n<\/ol>\n\n\n\n
    \n

    “PTO records provide poor notice regarding current ownership of patents.” \u2014 Federal Trade Commission testimony, cited in a 2012 comment to the USPTO on patent assignment recordation [10]<\/p>\n<\/blockquote>\n\n\n\n

    Patent Existence and Patent Control Are Different Questions<\/strong><\/h2>\n\n\n\n

    A patent monitoring program built around expiration dates answers one question: when does exclusivity end. It does not answer who currently owns the exclusivity, who can sue to enforce it, who collects the money from it, or who decides whether to challenge, license, or abandon it. Those are four distinct control signals, and each one can sit with a different party.<\/p>\n\n\n\n

    What the Assignee of Record Actually Tells You<\/strong><\/h3>\n\n\n\n

    The assignee of record is whichever party has recorded a chain-of-title document with the USPTO. It is a legal signal, not necessarily a current one. The USPTO does not independently verify assignments before recording them. As the agency’s own manual states, recordation is available to any submitted document related to ownership, and the office plays no role in confirming the transfer is accurate or complete [11]. That means the assignee of record can lag the real owner by months, or in some cases never catch up at all if nobody bothers to file the paperwork.<\/p>\n\n\n\n

    The Orange Book Lists the NDA Holder, Not Necessarily the Patent Owner<\/strong><\/h3>\n\n\n\n

    A second, separate signal is the FDA’s Orange Book listing, which shows the NDA holder, not the patent’s actual owner. These usually match. After a merger, spin-off, or licensing deal, they do not have to. A generic company checking exposure by looking only at the Orange Book applicant name can miss a control change that already happened at the patent-office level, or miss one that has not yet propagated to the FDA’s records at all.<\/p>\n\n\n\n

    The Recordation Gap: Why USPTO Records Are an Unreliable Control Signal<\/strong><\/h2>\n\n\n\n

    The legal mechanics behind this gap are set out in a single statute. Under 35 U.S.C. \u00a7 261, a patent assignment is void against a later, good-faith purchaser unless it is recorded at the USPTO within three months of execution, or before that later purchase happens [12]. The rule exists to protect buyers who check the public record before a transaction. It does not require every assignment to be recorded promptly, and it creates no penalty for a company that simply never records at all, so long as no competing claim ever surfaces.<\/p>\n\n\n\n

    Patent attorneys who work with the recordation system describe it as functionally optional in practice, since recordation is “merely ministerial at the USPTO” and the agency makes no determination as to whether a given assignment is valid [13]. The three-month window matters only in the specific scenario the statute was written for: a race between two buyers of the same rights. Outside that scenario, an unrecorded or late-recorded assignment can sit in a company’s files for years while the public patent record shows the prior owner.<\/p>\n\n\n\n

    Professor Colleen Chien’s 2012 comment to the USPTO, filed in response to the agency’s own request for ways to improve assignment data quality, quantified how often this timing gap shows up in litigation. Reviewing patent infringement cases from 2000 through 2008, the comment found that in roughly 10 percent of cases the plaintiff had been assigned the patent before filing suit but recorded that assignment only afterward, and in 4.6 percent of cases the assignment to the plaintiff was recorded only after the lawsuit had already started [10]. In other words, in a meaningful share of patent suits, the public record did not show who owned the patent being litigated until after the litigation began.<\/p>\n\n\n\n

    Control Signal<\/th>What It Actually Shows<\/th>Where To Check It<\/th>Common Failure Mode<\/th><\/tr>
    Assignee of record<\/td>Legal title as last recorded<\/td>USPTO Patent Assignment Search<\/td>Recordation lag; no requirement to record promptly outside a purchaser-priority dispute [12][13]<\/td><\/tr>
    NDA\/BLA holder<\/td>Regulatory approval holder<\/td>FDA Orange Book \/ Purple Book<\/td>Does not update automatically when patent title changes hands<\/td><\/tr>
    Royalty owner<\/td>Economic interest in future sales<\/td>SEC filings, company press releases<\/td>Almost never appears in any patent database at all [14]<\/td><\/tr>
    Litigation party of record<\/td>Who is actually suing or being sued today<\/td>PACER, PTAB dockets<\/td>Substitution of parties after M&A is not always publicized<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    Case Study: When a $74 Billion Merger Splits a Patent Portfolio in Two<\/strong><\/h2>\n\n\n\n

    Bristol Myers Squibb announced its acquisition of Celgene on January 3, 2019, in a deal valued at $74 billion [15]. Celgene’s most valuable near-term asset, the psoriasis drug Otezla, was not part of what BMS ultimately controlled after closing. To secure FTC clearance, Celgene agreed in August 2019 to sell Otezla’s global rights, including its patent estate, to Amgen for $13.4 billion, a divestiture the FTC accepted on November 15, 2019, five days before the BMS-Celgene deal itself closed [2][3]. Amgen completed the Otezla acquisition on November 21, 2019 [3].<\/p>\n\n\n\n

    Timeline: Announcement to Antitrust Carve-Out<\/strong><\/h3>\n\n\n\n
    Date<\/th>Event<\/th><\/tr>
    January 3, 2019<\/td>BMS announces $74B acquisition of Celgene [15]<\/td><\/tr>
    August 25, 2019<\/td>Celgene signs agreement to divest Otezla to Amgen for $13.4B [2]<\/td><\/tr>
    November 15, 2019<\/td>FTC accepts consent order permitting the BMS-Celgene deal to close, conditioned on the Otezla divestiture [2]<\/td><\/tr>
    November 20, 2019<\/td>BMS-Celgene acquisition closes [16]<\/td><\/tr>
    November 21, 2019<\/td>Otezla divestiture to Amgen completes [3]<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    What This Reveals About M&A Control<\/strong><\/h3>\n\n\n\n

    A patent tracker built around the announcement date alone would have flagged every Celgene patent, including Otezla’s, as moving to BMS. The actual outcome split the portfolio between two acquirers based on a regulatory condition negotiated after the deal was announced and finalized only days before closing. Revlimid, Celgene’s largest asset by revenue, stayed with BMS and came with its own separate complication: the drug’s dosing and formulation patents were still under active challenge at the time of the merger, meaning BMS acquired not just the patent estate but the ongoing litigation risk to it [17].<\/p>\n\n\n\n

    Case Study: The Acquirer Inherits the Fight, Not Just the Patent<\/strong><\/h2>\n\n\n\n

    AstraZeneca’s acquisition of Alexion was announced December 12, 2020 and closed in the third quarter of 2021, for total consideration of roughly $39 billion [5]. Alexion’s complement-inhibitor franchise, built around Soliris and its successor Ultomiris, came with a patent dispute that predated the acquisition by half a decade: Alexion and Roche’s Chugai Pharmaceutical had been contesting Ultomiris-related intellectual property since at least 2016, with Chugai filing infringement suits in Japan and the United States in 2018 and a third U.S. suit in 2019 [18].<\/p>\n\n\n\n

    AstraZeneca did not settle that inherited dispute until March 2022, agreeing to pay Chugai $775 million as a single lump sum with no ongoing royalty obligation attached [18][4]. The settlement came roughly eight months after AstraZeneca had taken over the Alexion patent estate, and the price tag reflected litigation exposure that originated entirely under the prior owner. Tracking the Ultomiris patent family by expiration date alone would have shown a healthy, unchallenged asset. Tracking who controlled it, and what liabilities came attached to that control, would have shown a nine-figure settlement waiting to be paid by whoever ended up holding the patents.<\/p>\n\n\n\n

    Case Study: Patent Ownership as Litigation Strategy, Not Business Strategy<\/strong><\/h2>\n\n\n\n

    Most patent ownership changes happen for commercial reasons: a merger, a licensing deal, a spin-off. Allergan’s 2017 transfer of six Restasis patents to the Saint Regis Mohawk Tribe was different. It happened for a single litigation reason: to attempt an end run around pending inter partes review at the Patent Trial and Appeal Board.<\/p>\n\n\n\n

    Why the Deal Failed<\/strong><\/h3>\n\n\n\n

    By September 2017, Mylan, Teva, and Akorn had multiple IPR petitions pending against Restasis patents, and Allergan faced the prospect of losing them at the PTAB [19]. On September 8, 2017, Allergan recorded an assignment transferring the patents to the Saint Regis Mohawk Tribe, a federally recognized tribe, in exchange for a $13.75 million upfront payment and royalties of up to $15 million annually [6][7]. The tribe then moved to terminate the IPR proceedings, arguing tribal sovereign immunity barred the board from hearing the case at all.<\/p>\n\n\n\n

    The PTAB denied that motion, and on July 20, 2018 the Federal Circuit affirmed in Saint Regis Mohawk Tribe v. Mylan Pharmaceuticals Inc., 896 F.3d 1322, holding that tribal sovereign immunity does not apply to inter partes review [20][6]. The Supreme Court declined to hear a further appeal in April 2019, closing the matter [7]. Allergan’s monopoly position on Restasis had already been substantially eroded by the time the case concluded [7].<\/p>\n\n\n\n

    The lesson for anyone tracking ownership: a recorded assignment is a real, legally effective transfer of title on its face, but the reason behind a transfer can determine whether the control it purports to grant actually holds up. A patent database has no way to flag “this assignment was recorded for defensive litigation reasons and may not survive judicial review.” Only tracking the underlying legal dispute alongside the ownership record would catch that.<\/p>\n\n\n\n

    Case Study: When the Owner Ceases to Exist<\/strong><\/h2>\n\n\n\n

    Purdue Pharma filed for Chapter 11 bankruptcy on September 15, 2019, facing thousands of lawsuits over OxyContin’s role in the opioid crisis [21][1]. What followed is the clearest illustration available of how long “who controls this patent estate” can remain a genuinely open legal question.<\/p>\n\n\n\n

    Six Years From Filing to Dissolution<\/strong><\/h3>\n\n\n\n

    A bankruptcy court initially confirmed a reorganization plan that shielded the Sackler family from future civil claims in exchange for a payment contribution. Multiple states and the U.S. Trustee objected, and the fight over that plan reached the Supreme Court. On June 27, 2024, the Court ruled 5-4 in Harrington v. Purdue Pharma, 603 U.S. 204, that the Bankruptcy Code does not permit a Chapter 11 plan to release claims against a non-debtor without the consent of the claimants involved [22][8]. That decision voided the plan structure entirely and sent the case back into negotiation.<\/p>\n\n\n\n

    Who Controls OxyContin’s Patents Today<\/strong><\/h3>\n\n\n\n

    A revised plan, raising the Sackler family’s total contribution toward a $7.4 billion settlement, won bankruptcy court confirmation on November 18, 2025 [23]. The plan went effective April 1, 2026, and Purdue Pharma’s pharmaceutical business restarted on May 1, 2026 as Knoa Pharma LLC, a public-benefit successor owned by the not-for-profit Knoa Foundation, which is itself owned, through a holding structure, by the National Opioid Abatement Trust and a separate Tribe Trust [1]. The Sackler family retained no ownership stake in the successor entity [1].<\/p>\n\n\n\n

    For roughly six and a half years, the entity that would ultimately control the OxyContin patent portfolio was undetermined, not because of any dispute over the patents themselves, but because the corporate vehicle holding them was tied up in a solvency fight whose outcome the Supreme Court reset from scratch partway through. A patent expiration tracker would have shown the same OxyContin patents throughout that period without ever flagging that their ultimate owner was a genuinely open question.<\/p>\n\n\n\n

    The Generic Side Has a Control Problem Too<\/strong><\/h2>\n\n\n\n

    Ownership tracking is usually framed as a brand-side problem, but the same dynamic plays out among generic challengers. Teva agreed in July 2015 to acquire Allergan’s Actavis Generics business for $40.5 billion, and the deal closed August 2, 2016 after a year of FTC review [24][25]. As a condition of clearance, Teva divested 79 separate generic drug businesses, spanning categories including anesthetics, antibiotics, weight-loss treatments, and oral contraceptives, to five separate buyers: Dr. Reddy’s, Aurobindo Pharma, Cipla, Mayne Pharma, and 3M [24].<\/p>\n\n\n\n

    Each of those 79 divested product lines came with whatever ANDA filings, Paragraph IV certifications, and pending patent litigation attached to them. A brand company monitoring which generic company was challenging its patents in early 2016 would have needed to re-verify that picture entirely by late 2016, not because any court ruled on anything, but because the identity of the challenger itself had been reassigned across five companies as a side effect of a single merger clearance.<\/p>\n\n\n\n

    Spin-Offs Divide Control Without a Sale<\/strong><\/h2>\n\n\n\n

    Not every control change involves a buyer and a seller. Merck completed the spin-off of Organon & Co. on June 2, 2021, distributing shares of the new, independently traded company to Merck’s own shareholders rather than selling the business to a third party [26][27]. Organon took with it Merck’s women’s health, biosimilars, and established-brands portfolios, including the patent-protected contraceptive implant Nexplanon and legacy cardiovascular products Zetia and Vytorin, representing roughly $6.5 billion in 2020 product sales [28][26].<\/p>\n\n\n\n

    Merck’s research pipeline programs, and the patents behind them, stayed inside Merck by design [26]. No cash changed hands for the transferred assets, no antitrust regulator imposed any condition, and no court was involved. Control over an entire category of patents moved simply because Merck’s board decided the businesses belonged in a separate public company. Any monitoring approach organized around “who bought what” would miss this category of control change entirely, since nothing was bought.<\/p>\n\n\n\n

    A Fourth Kind of Control: Owning the Economics Without Owning the Patent<\/strong><\/h2>\n\n\n\n

    The clearest illustration that patent ownership and patent control are not the same thing comes from royalty monetization. Royalty Pharma, founded in 1996, built its business specifically around acquiring the economic interest in a drug’s future sales without acquiring the patent itself [29]. In one of its largest early deals, Royalty Pharma paid $3.3 billion in 2014 for the Cystic Fibrosis Foundation’s royalty interest in drugs developed with the foundation’s funding, including Vertex’s Kalydeco, the compound that led to Trikafta and its successor Alyftrek [29].<\/p>\n\n\n\n

    Vertex kept the patents. It kept the right to sue infringers. It kept the regulatory approvals. What it did not keep, because the Cystic Fibrosis Foundation had never held it in the first place, was the entire economic upside the foundation’s funding agreement had entitled it to. That upside now belongs to Royalty Pharma. The pattern continues in real time: on August 12, 2026, Zealand Pharma sold its economic interest in rusfertide, an experimental blood-disorder therapy being developed by Takeda and Protagonist Therapeutics, to Royalty Pharma for $100 million, retaining a smaller residual royalty for itself while giving up the larger 0.75 percent slice of future sales above $1.5 billion [30][31].<\/p>\n\n\n\n

    Neither Zealand nor Royalty Pharma is listed as the patent assignee for rusfertide in that transaction, since Zealand’s interest was contractual, not a title interest in Takeda and Protagonist’s underlying patents [30]. A patent database has no field for this kind of control at all. It requires checking SEC filings and company disclosures, the same sources platforms built for pharmaceutical intelligence, including DrugPatentWatch, point to when tracing whether a drug’s economics have been licensed or sold separately from its patent title [14].<\/p>\n\n\n\n

    An Original Taxonomy: Four Ways Pharma Patent Control Changes Hands<\/strong><\/h2>\n\n\n\n
    Control-Change Type<\/th>Trigger<\/th>What Typically Moves<\/th>Example<\/th><\/tr>
    M&A transfer with antitrust carve-out<\/td>Merger clearance conditions<\/td>Title, sometimes split across the acquirer and a third-party divestiture buyer<\/td>BMS-Celgene \/ Otezla to Amgen [2][3]<\/td><\/tr>
    Litigation-defense transfer<\/td>Attempt to alter forum or immunity posture<\/td>Title only; enforcement posture is what the transfer is meant to change<\/td>Allergan-Saint Regis Mohawk Tribe (Restasis) [6][7]<\/td><\/tr>
    Insolvency\/bankruptcy transfer<\/td>Chapter 11 reorganization<\/td>Corporate ownership of the entire estate, patents included, pending court approval<\/td>Purdue Pharma to Knoa Pharma [1][8]<\/td><\/tr>
    Corporate division without sale<\/td>Board-level strategic separation<\/td>Title, split by business unit rather than by transaction<\/td>Organon spin-off from Merck [26][27]<\/td><\/tr>
    Economic-only transfer<\/td>Royalty monetization<\/td>Future revenue interest; title and enforcement rights stay with the original owner<\/td>Royalty Pharma \/ CFF-Vertex; Royalty Pharma \/ Zealand-rusfertide [29][30]<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    What Happens When You Track Patents Instead of Owners<\/strong><\/h2>\n\n\n\n

    Put the five case studies side by side and a pattern emerges: every one of them would have been invisible to a monitoring approach organized around patent numbers and expiration dates. Each was visible to a monitoring approach organized around corporate filings, court dockets, and regulatory clearance conditions instead.<\/p>\n\n\n\n

    What a Patent-Number Tracker Shows<\/th>What a Control Tracker Also Shows<\/th><\/tr>
    Otezla’s patents are Celgene’s, then BMS’s<\/td>An FTC divestiture condition sent Otezla to Amgen, a company outside the original deal [2][3]<\/td><\/tr>
    Ultomiris patents transferred cleanly to AstraZeneca<\/td>A five-year-old, unresolved Chugai dispute transferred with them, later settled for $775M [18][4]<\/td><\/tr>
    Restasis patents belong to the Saint Regis Mohawk Tribe<\/td>The Federal Circuit ruled the transfer did not block IPR review of the same patents [6][20]<\/td><\/tr>
    OxyContin’s patents remain assigned to Purdue Pharma entities<\/td>The entity holding them was legally unsettled for six-plus years and ultimately dissolved [1][8]<\/td><\/tr>
    Rusfertide’s patents remain with Takeda\/Protagonist<\/td>Zealand Pharma sold the economic upside on those same patents to a third party [30]<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    What This Means for Brand Manufacturers<\/strong><\/h2>\n\n\n\n

    A brand portfolio manager evaluating M&A risk to an in-licensed or recently acquired patent estate needs three data points a standard patent search will not surface on its own: whether any antitrust clearance conditions attached to the deal that brought the patents in-house, whether unresolved third-party litigation existed under the prior owner, and whether the assignment recording the transfer happened inside or outside the three-month window that determines its priority against a later claimant [12][13]. All three sit outside the patent record itself.<\/p>\n\n\n\n

    What This Means for Generic and Biosimilar Challengers<\/strong><\/h2>\n\n\n\n

    A generic company tracking Paragraph IV exposure across a competitor’s portfolio needs to re-verify ownership after any M&A event involving either side of a pending dispute, not only the brand side. Teva’s 79-business FTC divestiture shows the same reassignment risk applies to challengers: a company that filed an ANDA in 2015 might not be the company defending or advancing that same filing by 2017, through no action of its own [24].<\/p>\n\n\n\n

    What This Means for Institutional Investors and Portfolio Managers<\/strong><\/h2>\n\n\n\n

    Revenue exposure tied to a specific patent estate is not the same question as who legally owns that estate. The Royalty Pharma model exists precisely because these two questions can be decoupled and separately valued. An investor modeling a company’s exposure to a loss-of-exclusivity event should confirm whether that company holds the full economic interest in the relevant patents or only a partial, already-monetized slice of it [29][30].<\/p>\n\n\n\n

    Methodology<\/strong><\/h2>\n\n\n\n

    This analysis draws on five publicly documented control-change events selected because each is independently confirmed through primary sources: federal court opinions, SEC filings, FTC consent orders, and company press releases. Dates and dollar figures are drawn from the primary filing or ruling where available, cross-checked against contemporaneous trade press coverage. The four-category taxonomy of control-change types is an original classification constructed from these five cases plus the royalty-monetization pattern documented separately; it is not an established industry framework and should be read as an analytical lens rather than a settled taxonomy. Limitations: the sample is illustrative, not exhaustive, and was selected for documentary clarity and public availability rather than statistical representativeness of all pharma ownership-change events.<\/p>\n\n\n\n

    Key Takeaways<\/strong><\/h2>\n\n\n\n
      \n
    • Patent ownership has at least four separable components: legal title, economic interest, enforcement rights, and regulatory listing, and each can sit with a different party at the same time.<\/li>\n\n\n\n
    • USPTO assignment records are a legal signal with a built-in lag; the three-month recordation rule under 35 U.S.C. \u00a7 261 only guarantees priority in a purchaser-priority dispute, not real-time accuracy [12][13].<\/li>\n\n\n\n
    • M&A-driven antitrust divestitures can route patents to companies that were never party to the original transaction, as with Otezla’s move to Amgen during the BMS-Celgene merger [2][3].<\/li>\n\n\n\n
    • Acquiring a patent portfolio means acquiring its unresolved litigation exposure, as AstraZeneca’s $775 million Chugai settlement over inherited Ultomiris claims demonstrates [18][4].<\/li>\n\n\n\n
    • A recorded patent assignment can be legally challenged after the fact based on the motive behind it, as the Saint Regis Mohawk Tribe transfer shows [6][20].<\/li>\n\n\n\n
    • Corporate insolvency can leave a patent estate’s ultimate ownership legally unresolved for years, as in Purdue Pharma’s six-and-a-half-year path to becoming Knoa Pharma [1][8].<\/li>\n\n\n\n
    • Royalty monetization separates economic control from legal title entirely, and this split appears in SEC filings and press releases rather than in any patent database [29][30].<\/li>\n<\/ul>\n\n\n\n

      FAQ<\/strong><\/h2>\n\n\n\n

      Does acquiring a company automatically transfer its patents to the buyer?<\/strong>
      Generally yes, but antitrust conditions can carve out specific assets. In the BMS-Celgene merger, Otezla’s entire patent estate went to Amgen instead of BMS, as a condition the FTC imposed before allowing the broader deal to close [2][3].<\/p>\n\n\n\n

      What happens to a patent lawsuit when the patent owner is acquired mid-case?<\/strong>
      The dispute transfers with the patent, and the acquirer becomes responsible for resolving it. AstraZeneca settled a Chugai patent dispute over Ultomiris for $775 million in 2022, a dispute that began under Alexion’s ownership in 2016, five years before AstraZeneca’s acquisition closed [18][4].<\/p>\n\n\n\n

      Can a company sell a patent’s economic value without selling the patent itself?<\/strong>
      Yes. Royalty Pharma’s business model is built on exactly this separation, buying future royalty streams while leaving legal title and enforcement rights with the original patent holder, as in its 2014 Cystic Fibrosis Foundation deal and its August 2026 rusfertide deal with Zealand Pharma [29][30].<\/p>\n\n\n\n

      Why did Allergan transfer Restasis patents to a Native American tribe?<\/strong>
      To attempt to use tribal sovereign immunity to block pending inter partes review challenges at the PTAB. The Federal Circuit ruled in July 2018 that tribal immunity does not apply in IPR proceedings, and the Supreme Court declined further review in April 2019 [6][20][7].<\/p>\n\n\n\n

      Does the USPTO verify who actually owns a patent before recording an assignment?<\/strong>
      No. Recordation is described by patent attorneys as a ministerial process; the agency does not determine whether a submitted assignment is valid or accurate before recording it [13].<\/p>\n\n\n\n

      What is the difference between a patent’s assignee of record and a drug’s Orange Book NDA holder?<\/strong>
      The assignee of record is whoever last recorded a chain-of-title document with the USPTO for that specific patent. The Orange Book NDA holder is the company the FDA recognizes as holding the drug’s marketing approval. The two usually match but are not required to, and neither updates automatically when the other changes.<\/p>\n\n\n\n

      What happens to a drug’s patents when the patent holder files for bankruptcy?<\/strong>
      The patents remain part of the bankruptcy estate until a reorganization plan is confirmed. Purdue Pharma’s case shows this process can take years and can be reversed mid-course: the Supreme Court voided Purdue’s first confirmed plan in June 2024, and a revised plan was not confirmed until November 2025, more than six years after the original filing [8][23][1].<\/p>\n\n\n\n

      How long does a company have to record a patent assignment with the USPTO?<\/strong>
      Three months from execution, or before a competing purchaser buys the same rights, under 35 U.S.C. \u00a7 261. Missing that window does not invalidate the assignment between the original parties, but it can cost the assignee priority against a later, good-faith buyer who had no notice of the earlier deal [12][13].<\/p>\n\n\n\n

      Do FTC-mandated divestitures change who is defending against generic patent challenges?<\/strong>
      They can. When Teva acquired Allergan’s Actavis Generics business in 2016, the FTC required Teva to divest 79 generic product lines to five separate companies, each of which took on whatever pending ANDA filings and patent challenges came attached to those products [24].<\/p>\n\n\n\n

      Is a patent assignment recorded for litigation reasons treated the same as one recorded for a business transaction?<\/strong>
      Legally, a recorded assignment is a recorded assignment. But courts can and do look past the recordation to the substance of the transfer. The Federal Circuit did exactly that with the Saint Regis Mohawk Tribe transfer, finding the underlying immunity claim invalid regardless of the completed assignment [6][20].<\/p>\n\n\n\n

      References<\/strong><\/h2>\n\n\n\n
        \n
      1. Purdue Pharma: $7.4 Billion Chapter 11 Plan Goes Effective, Knoa Pharma Begins Operations. Elevenflo, May 2026. https:\/\/elevenflo.com\/blog\/purdue-pharma-chapter-11-opioid-settlement<\/li>\n\n\n\n
      2. Bristol Myers Squibb Co., Form 10-K, FY2019. U.S. Securities and Exchange Commission. https:\/\/www.sec.gov\/Archives\/edgar\/data\/0000014272\/000001427220000082\/bmy-20191231x10xk.htm<\/li>\n\n\n\n
      3. Bristol-Myers Squibb Completes Acquisition of Celgene, Creating a Leading Biopharma Company. Nasdaq press release, November 2019. https:\/\/www.nasdaq.com\/press-release\/bristol-myers-squibb-completes-acquisition-of-celgene-creating-a-leading-biopharma<\/li>\n\n\n\n
      4. After Alexion buyout, AstraZeneca pays Roche $775M to settle Ultomiris patent brawl. Fierce Pharma, March 2022. https:\/\/www.fiercepharma.com\/pharma\/astrazeneca-pays-roche-775m-settle-ultomiris-patent-brawl<\/li>\n\n\n\n
      5. Alexion Pharmaceuticals, Form 425, FY2021. U.S. Securities and Exchange Commission. https:\/\/www.sec.gov\/Archives\/edgar\/data\/899866\/000114036121002033\/nt10017928x15_425.htm<\/li>\n\n\n\n
      6. Saint Regis Mohawk Tribe v. Mylan Pharmaceuticals Inc., 896 F.3d 1322 (Fed. Cir. 2018). FindLaw. https:\/\/caselaw.findlaw.com\/court\/us-federal-circuit\/1943514.html<\/li>\n\n\n\n
      7. Supreme Court rejects Allergan, Saint Regis Mohawk appeal in patent case. MedCity News, April 2019. https:\/\/medcitynews.com\/2019\/04\/supreme-court-rejects-allergan-saint-regis-mohawk-appeal-in-patent-case\/<\/li>\n\n\n\n
      8. Harrington v. Purdue Pharma L.P., 603 U.S. 204 (2024). Supreme Court of the United States. https:\/\/www.supremecourt.gov\/opinions\/23pdf\/23-124_8nk0.pdf<\/li>\n\n\n\n
      9. Teva Completes Actavis Acquisition and Picks Up Anda, Inc. from Allergan. Pharmaceutical Technology, 2016. https:\/\/www.pharmtech.com\/view\/teva-completes-actavis-acquisition-and-picks-anda-inc-allergan<\/li>\n\n\n\n
      10. Chien, Colleen. Eliciting More Complete Patent Assignment Information. Comment to the USPTO, Docket No. PTO-P-2011-0077, January 2012. https:\/\/www.uspto.gov\/sites\/default\/files\/patents\/law\/comments\/f_chien_120123.pdf<\/li>\n\n\n\n
      11. MPEP 301: Ownership\/Assignability of Patents and Applications. United States Patent and Trademark Office. https:\/\/www.uspto.gov\/web\/offices\/pac\/mpep\/s301.html<\/li>\n\n\n\n
      12. 35 U.S.C. \u00a7 261, Ownership; assignment. Office of the Law Revision Counsel, U.S. House of Representatives. https:\/\/uscode.house.gov\/view.xhtml?req=granuleid%3AUSC-prelim-title35-section261<\/li>\n\n\n\n
      13. Patent Chain of Title: How Broken Assignment Links Destroy IP Portfolio Value. UC Berkeley Law, May 2026. https:\/\/www.law.berkeley.edu\/research\/bclt\/bclt-legal-analysis\/start-up-s3\/<\/li>\n\n\n\n
      14. Drug Patent Licensing: The Complete Intelligence Playbook for Pharma Analysts and IP Teams. DrugPatentWatch, 2026. https:\/\/www.drugpatentwatch.com\/blog\/how-do-you-check-if-a-drug-patent-has-been-licensed\/<\/li>\n\n\n\n
      15. Bristol-Myers Squibb’s $74 billion acquisition of Celgene would combine two troubled companies. CNBC, January 2019. https:\/\/www.cnbc.com\/2019\/01\/03\/bristol-myers-squibb-shares-fall-on-74-billion-celgene-acquisition.html<\/li>\n\n\n\n
      16. BMS completes $74bn Celgene acquisition. PharmaTimes, 2019. https:\/\/pharmatimes.com\/news\/bms_competes_74bn_celgene_acquisition_1317844\/<\/li>\n\n\n\n
      17. The BMS-Celgene merger’s Achilles heel? An earlier-than-expected Revlimid patent loss. Fierce Pharma, January 2019. https:\/\/www.fiercepharma.com\/pharma\/bristol-myers-boosts-oncology-pipeline-celgene-buyout-but-revlimid-patent-worries-abound<\/li>\n\n\n\n
      18. AstraZeneca pays $775M to settle patent dispute over Alexion drug. BioPharma Dive, March 2022. https:\/\/www.biopharmadive.com\/news\/astrazeneca-chugai-patent-dispute-ultomiris-alexion\/620573\/<\/li>\n\n\n\n
      19. The St. Regis Mohawk Tribe and Restasis patent. Wikipedia. https:\/\/en.wikipedia.org\/wiki\/The_St._Regis_Mohawk_Tribe_and_Restasis_patent<\/li>\n\n\n\n
      20. Federal Circuit Nixes PTAB Sovereign Immunity for Saint Regis Mohawk Tribe. Foley Hoag, July 2018. https:\/\/foleyhoag.com\/news-and-insights\/publications\/alerts-and-updates\/2018\/july\/federal-circuit-nixes-ptab-sovereign-immunity-for-saint-regis-mohawk-tribe\/<\/li>\n\n\n\n
      21. Harrington v. Purdue Pharma: Supreme Court Holds That a Chapter 11 Reorganization Plan Cannot Include a Nonconsensual Release of Claims Against Non-Debtors. Congressional Research Service, July 2024. https:\/\/www.congress.gov\/crs-product\/LSB11201<\/li>\n\n\n\n
      22. Supreme Court Decides Harrington v. Purdue Pharma L.P. Faegre Drinker, June 2024. https:\/\/www.faegredrinker.com\/en\/insights\/publications\/2024\/6\/supreme-court-decides-harrington-v-purdue-pharma-lp<\/li>\n\n\n\n
      23. Sackler family, Purdue Pharma’s $7.4B settlement plan wins bankruptcy judge’s approval. Fierce Pharma, November 2025. https:\/\/www.fiercepharma.com\/pharma\/sackler-family-purdue-pharma-can-settle-opioid-claims-74b-deal-judge-signs-bankruptcy<\/li>\n\n\n\n
      24. Teva completes acquisition of Allergan’s generics business. Irish Times, August 2016. https:\/\/www.irishtimes.com\/business\/health-pharma\/teva-completes-acquisition-of-allergan-s-generics-business-1.2743471<\/li>\n\n\n\n
      25. Teva Pharmaceuticals has acquired success with Actavis Generics. World Finance, 2016. https:\/\/www.worldfinance.com\/strategy\/corporate-finance\/teva-pharmaceuticals-acquiring-success<\/li>\n\n\n\n
      26. Merck & Co., Inc., Form 10-K, FY2021. U.S. Securities and Exchange Commission. https:\/\/www.sec.gov\/Archives\/edgar\/data\/310158\/000031015822000003\/mrk-20211231.htm<\/li>\n\n\n\n
      27. Organon & Co. Wikipedia. https:\/\/en.wikipedia.org\/wiki\/Organon_%26_Co.<\/li>\n\n\n\n
      28. Organon: What’s Next for the New Merck & Co. Spin-off? DCAT Value Chain Insights, October 2021. https:\/\/www.dcatvci.org\/features\/organon-what-s-next-for-the-new-merck-co-spin-off\/<\/li>\n\n\n\n
      29. Royalty Pharma. Wikipedia. https:\/\/en.wikipedia.org\/wiki\/Royalty_Pharma<\/li>\n\n\n\n
      30. Zealand Pharma enters into a USD 100 million royalty purchase and sale agreement with Royalty Pharma for the economics related to rusfertide. GlobeNewswire, August 2026. https:\/\/www.globenewswire.com\/news-release\/2026\/08\/12\/3344048\/0\/en\/zealand-pharma-enters-into-a-usd-100-million-royalty-purchase-and-sale-agreement-with-royalty-pharma-for-the-economics-related-to-rusfertide.html<\/li>\n\n\n\n
      31. Royalty Pharma Enters $100M Rusfertide Funding Deal. StockTitan \/ RPRX Stock News, August 2026. https:\/\/www.stocktitan.net\/news\/RPRX\/royalty-pharma-and-zealand-pharma-enter-into-rusfertide-funding-77wrcaxiz0vj.html<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

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