DCT

2:26-cv-12587

Takeda Pharmaceutical Co Ltd v. Qilu Pharmaceutical Hainan Co Ltd

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Complaint
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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:26-cv-12587, D.N.J., 09/23/2026
  • Venue Allegations: Plaintiff alleges venue is proper in the District of New Jersey because Defendant conducts business in the United States and New Jersey, the district is a likely destination for the accused product, and Defendant has previously consented to personal jurisdiction and availed itself of courts in the district in prior litigation.
  • Core Dispute: This is a Hatch-Waxman Act case in which Plaintiff Takeda alleges that Defendant Qilu’s submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of Takeda's antiviral drug LIVTENCITY® (maribavir) constitutes an act of infringement of a patent covering methods of using the drug.
  • Technical Context: The technology relates to pharmaceutical methods for treating cytomegalovirus (CMV), a common and serious viral infection, particularly in post-transplant patients with compromised immune systems.
  • Key Procedural History: The lawsuit was triggered by Qilu’s submission of an ANDA with a Paragraph IV certification, asserting that its proposed generic drug would not infringe Takeda’s patent or that the patent is invalid. The complaint notes several other related lawsuits filed by Takeda against other generic manufacturers for the same drug, as well as a prior case against Qilu, indicating a broad effort to enforce patent protection for LIVTENCITY®.

Case Timeline

Date Event
2010-10-28 Earliest Priority Date for '368 Patent
2026-06-23 '368 Patent Issued
2026-09-11 Qilu's Notice Letter to Takeda
2026-09-23 Complaint Filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 12,661,368 - "Maribavir Isomers, Compositions, Methods of Making and Methods of Using"

  • Patent Identification: U.S. Patent No. 12,661,368, "Maribavir Isomers, Compositions, Methods of Making and Methods of Using," issued June 23, 2026.

The Invention Explained

  • Problem Addressed: The patent’s background section describes the "unexpected discovery that maribavir may isomerize under in vivo conditions" into different, potentially less effective molecular forms ’368 Patent, col. 1:63-65 This isomerization is believed to "decrease the effective biological activity" of the administered drug, which the patent suggests may explain why a Phase 3 clinical trial failed its primary endpoint after a more promising Phase 2 trial had succeeded ’368 Patent, col. 2:25-27 ’368 Patent, col. 2:28-35 The patent identifies a key difference: the successful trial used a "fasted dosing protocol," while the failed trial permitted dosing with food, a condition believed to promote the undesirable isomerization ’368 Patent, col. 2:50-57
  • The Patented Solution: The invention claims to solve this problem by defining a specific method of administration designed to enhance efficacy by controlling for factors that lead to isomerization. The patent claims a method of treating CMV by orally administering maribavir at a specific dose ("400 mg twice a day") in an "immediate release formulation" that dissolves quickly ’368 Patent, claim 1 The specification details that maribavir should be administered in ways that "prevent or at least reduce the unwanted occurrence of maribavir isomerization in vivo," such as under fasted conditions ’368 Patent, col. 3:10-13 ’368 Patent, col. 4:64-65
  • Technical Importance: The patented method provides a potential pathway to clinical and commercial viability for maribavir by identifying a previously unrecognized variable (in vivo isomerization) and proposing a specific dosing and formulation strategy to manage it, thereby rescuing a drug that had shown mixed results in late-stage clinical trials ’368 Patent, col. 2:48-65

Key Claims at a Glance

  • The complaint asserts infringement of "one or more claims" of the ’368 Patent, which contains two independent method claims ’368 Patent, claims 1-2 Compl. ¶28
  • Independent Claim 1 consists of the following essential elements:
    • A method of treating a cytomegalovirus (CMV) infection in a patient having a CMV infection, the method comprising
    • orally administering to the patient the compound 5,6-dichloro-2-(isopropylamino)-1-(β-L-ribofuranosyl)-1H-benzimidazole
    • in an amount of 400 mg twice a day,
    • wherein said compound is administered as a composition comprising a therapeutically acceptable adjuvant, excipient, or carrier medium,
    • wherein said composition is an immediate release formulation,
    • and wherein the immediate release formulation releases said compound from said formulation by dissolution in less than 60 minutes.
  • Claim 2 is substantially similar, but defines the release characteristic as occurring "in vivo in less than 60 minutes following administration" ’368 Patent, claim 2 The complaint does not specify which claims are asserted but reserves the right to assert any of them.

III. The Accused Instrumentality

  • Product Identification: The accused instrumentality is "Qilu's ANDA Product," a proposed generic version of Takeda's LIVTENCITY® (maribavir) in the form of 200 mg tablets, for which Qilu has filed ANDA No. 221142 seeking FDA approval Compl. ¶22 Compl. ¶28
  • Functionality and Market Context:
    • As a generic drug submitted under an ANDA, Qilu's product is intended to be a therapeutic equivalent to the branded drug, LIVTENCITY® Compl. ¶26
    • LIVTENCITY® is a pUL97 kinase inhibitor indicated for treating post-transplant CMV infection/disease that is refractory to other antiviral treatments Compl. ¶5
    • The infringement theory is predicated on the requirement that a generic drug's labeling must substantially mirror that of the reference listed drug. The complaint alleges that the FDA-approved label for LIVTENCITY® "instructs and encourages" administration according to the patented method, and that Qilu's generic product label will therefore do the same Compl. ¶8

IV. Analysis of Infringement Allegations

The complaint does not contain a detailed claim chart. The infringement allegations are based on the statutory act of filing an ANDA seeking approval to market a generic drug for an infringing use prior to patent expiration Compl. ¶28 The following table summarizes the infringement theory as inferred from the complaint and the nature of ANDA litigation.

'368 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating a cytomegalovirus (CMV) infection in a patient having a CMV infection... Qilu's ANDA product is a generic version of LIVTENCITY®, which is indicated for the treatment of CMV infection. ¶5 col. 8:1-2
orally administering to the patient the compound 5,6-dichloro-2-(isopropylamino)-1-(β-L-ribofuranosyl)-1H-benzimidazole The accused product consists of "maribavir tablets," which are intended for oral administration as instructed on the product label. ¶22 col. 5:12
in an amount of 400 mg twice a day It is alleged that the label for Qilu's 200 mg tablets will instruct patients to take two tablets twice daily to achieve the approved 400 mg dose. ¶22 col. 8:2-3
wherein said composition is an immediate release formulation...and wherein the immediate release formulation releases said compound from said formulation by dissolution in less than 60 minutes. It is alleged that to be bioequivalent to the branded immediate-release LIVTENCITY® product, Qilu's ANDA product must also be an immediate-release formulation meeting this dissolution profile. ¶26 col. 8:6-10

No probative visual evidence provided in complaint.

  • Identified Points of Contention:
    • Technical Question: A key factual question for the court will be whether Qilu’s proposed generic product, as described in its ANDA, actually meets the quantitative limitation of an "immediate release formulation" that releases the compound "by dissolution in less than 60 minutes." Discovery into Qilu's ANDA filing will be necessary to obtain the evidence to resolve this question.
    • Scope Question: The case will likely depend heavily on a theory of induced infringement. This raises the legal question of whether the instructions for use in Qilu’s proposed product label will be found to actively encourage or instruct physicians and patients to perform each and every step of the patented method, thereby establishing the specific intent required for inducement.

V. Key Claim Terms for Construction

  • The Term: "immediate release formulation"
  • Context and Importance: This term is critical, as the patent uses the formulation type to distinguish the claimed method from the conditions that allegedly caused the prior Phase 3 clinical trial to fail. Practitioners may focus on this term because its construction will determine whether Qilu's bioequivalent product falls within the scope of the claims.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent provides its own definition. Both Claim 1 and the specification state that an "immediate release" formulation is one that releases the drug "by dissolution in less than 60 minutes" ’368 Patent, claim 1 ’368 Patent, col. 6:30-34 A party may argue that this performance-based definition should control, meaning any formulation that meets this dissolution standard infringes, regardless of its specific composition.
    • Evidence for a Narrower Interpretation: A party could argue that the term should be read in light of the problems described in the specification, such as isomerization under "fed" conditions ’368 Patent, col. 2:50-65 This could support an argument that the term implies a formulation specifically designed or tested for administration under "fasted conditions," potentially narrowing the claim scope ’368 Patent, col. 6:4-11

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement.
    • The inducement allegation is based on the assertion that Qilu, with knowledge of the '368 patent, will sell its product with a label that intentionally encourages direct infringement by instructing users to follow the patented method Compl. ¶31
    • The contributory infringement allegation is based on the assertion that Qilu's product is especially adapted for an infringing use and has no substantial non-infringing use Compl. ¶32
  • Willful Infringement: While the complaint does not use the term "willful," it alleges that Qilu has had "knowledge of the '368 patent since at least the date of Qilu's Paragraph IV Certification" Compl. ¶33 It also pleads that the case is "exceptional" and requests attorneys' fees under 35 U.S.C. § 285, which is the statutory basis for such an award, often in cases of willful or egregious conduct Compl. ¶35 Compl., prayer J

VII. Analyst’s Conclusion: Key Questions for the Case

The resolution of this Hatch-Waxman litigation will likely depend on the court's findings on three central questions:

  • A core issue will be one of claim construction and scope: can the term "immediate release formulation," as defined by the patent’s quantitative dissolution limit, be met simply by the bioequivalence data required for an ANDA filing, or will specific evidence from Qilu's formulation be required to prove it falls within the claim?
  • A key legal question will be one of induced infringement: does the anticipated language on the label for Qilu's generic product rise to the level of actively instructing or encouraging prescribers and patients to administer the drug in the specific "400 mg twice a day" regimen, thereby establishing the requisite intent for infringement?
  • Finally, a central validity question, which Qilu will almost certainly raise in its defense, will be one of obviousness: was it obvious for a person of ordinary skill in the art to arrive at the claimed method of administering maribavir, given the public knowledge and the results of the prior clinical studies disclosed in the patent's own background section?