DCT

1:24-cv-01264

Shionogi & Co Ltd v. Norwich Pharma Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:24-cv-01264, D. Del., 11/18/2024
  • Venue Allegations: Venue is asserted to be proper in the District of Delaware because both Defendant entities are organized and existing under the laws of Delaware.
  • Core Dispute: Plaintiffs allege that Defendants' filing of an Abbreviated New Drug Application (ANDA) for generic versions of the influenza drug XOFLUZA® constitutes an act of infringement of a patent covering a specific tablet formulation.
  • Technical Context: The technology relates to pharmaceutical formulations for oral tablets, specifically focusing on coatings that enhance the stability of the active drug ingredient against light degradation while ensuring proper dissolution for efficacy.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendants' submission of ANDA No. 217449 to the U.S. Food and Drug Administration (FDA). The FDA granted tentative approval for the ANDA on September 13, 2023. The complaint notes a related, previously-filed action between the parties ("23-161, D. Del.") concerning other patents listed for XOFLUZA®.

Case Timeline

Date Event
2017-11-17 U.S. Patent No. 12,064,438 Priority Date
2022-12-29 Date of Defendants' Notice Letter regarding other patents
2023-09-13 FDA Tentative Approval of ANDA No. 217449
2024-08-20 U.S. Patent No. 12,064,438 Issued
2024-11-18 Complaint Filed

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

  • Patent Identification: U.S. Patent No. 12,064,438, "Pharmaceutical Preparation Excellent in Light Stability and Dissolution Property," issued on August 20, 2024.
  • The Invention Explained:
    • Problem Addressed: The patent identifies a dual technical challenge for pharmaceutical preparations containing the antiviral compound baloxavir marboxil (referred to as "formula (I)"). First, the compound is susceptible to discoloration when exposed to light. Second, the compound has low solubility, which can hinder its dissolution and absorption into the body. (ʼ438 Patent, col. 3:19-25).
    • The Patented Solution: The invention addresses these problems through a specific formulation for a solid tablet. The core innovation is a coating layer applied to the tablet. This coating contains both a "light stabilizing substance" (such as titanium oxide or talc) to prevent light-induced degradation and a specific polymer (such as hypromellose) that acts as a film-former. The tablet core itself must contain "croscarmellose sodium," a specific disintegrant chosen for its ability to improve dissolution without creating excess impurities. (ʼ438 Patent, Abstract; col. 9:43-10:2; col. 13:15-40).
    • Technical Importance: For a prodrug like baloxavir marboxil, which must be converted into its active form in the body, achieving both chemical stability on the shelf and predictable dissolution upon ingestion is critical for ensuring a safe and effective therapeutic dose reaches the patient. (ʼ438 Patent, col. 1:56-2:10).
  • Key Claims at a Glance:
    • The complaint asserts infringement of claims 1-8 and 10-14, with Claim 1 being the sole independent claim from which the others depend. (Compl. ¶38).
    • Independent Claim 1 requires:
      • A solid preparation comprising:
      • The active compound (baloxavir marboxil) or its salt;
      • Croscarmellose sodium; and
      • A coating layer that comprises at least one light-stabilizing substance and at least one polymer from the group of hypromellose, polyvinyl alcohol, and hydroxypropyl cellulose;
      • Wherein the preparation is a tablet coated with said coating layer. (ʼ438 Patent, col. 47:2-48:3).
    • The complaint alleges infringement either literally or under the doctrine of equivalents. (Compl. ¶38).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are the generic 40 mg and 80 mg baloxavir marboxil tablets for oral use for which Defendants seek FDA approval via ANDA No. 217449 (the "Proposed ANDA Products"). (Compl. ¶1).
  • Functionality and Market Context:
    • The Proposed ANDA Products are intended to serve as generic equivalents to Plaintiffs' brand-name influenza drug, XOFLUZA®. (Compl. ¶1, ¶8).
    • As generic equivalents, the products must demonstrate bioequivalence to XOFLUZA®, meaning they are expected to be absorbed and perform in the body in the same manner. (Compl. ¶34).
    • The complaint alleges, on information and belief, that the formulation used in the Proposed ANDA Products is covered by the claims of the ʼ438 Patent and that Defendants intend to market these products in the United States upon receiving final FDA approval. (Compl. ¶12, ¶33).

IV. Analysis of Infringement Allegations

The complaint does not provide a detailed claim chart exhibit. The infringement allegations are based on the statutory act of infringement under 35 U.S.C. § 271(e)(2)—the submission of an ANDA seeking approval to market a drug claimed in a patent before that patent's expiration. (Compl. ¶39). The following table summarizes the likely infringement theory for the lead independent claim.

No probative visual evidence provided in complaint.

'438 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A solid preparation comprising: a compound represented by the formula (I) or a pharmaceutically acceptable salt thereof... The Proposed ANDA Products are tablets containing baloxavir marboxil, which is the compound of formula (I). ¶1, ¶12 col. 47:4-18
croscarmellose sodium The complaint alleges on information and belief that the Proposed ANDA Products use a formulation covered by the asserted claims, which would require the presence of croscarmellose sodium as a disintegrant. ¶33, ¶38 col. 47:19-20
a coating layer comprising at least one light-stabilizing substance and at least one polymer selected from the group consisting of hypromellose, polyvinyl alcohol and hydroxypropyl cellulose It is alleged that the Proposed ANDA Products are coated tablets whose formulation infringes. To achieve the required stability and bioequivalence, the infringement theory posits that Defendants' formulation must use a coating system with the claimed components. ¶33, ¶38 col. 47:21-27
wherein the solid preparation is in the form of a tablet, and the tablet is coated by the coating layer. The Proposed ANDA Products are described as tablets for oral use. ¶1, ¶12 col. 47:28-30
  • Identified Points of Contention:
    • Technical Questions: The central factual question is whether the formulation described in Defendants' confidential ANDA submission literally meets every limitation of Claim 1. Does it specifically use "croscarmellose sodium" as a disintegrant, or another substance? Does the coating layer contain one of the three specified polymers ("hypromellose, polyvinyl alcohol and hydroxypropyl cellulose")? The complaint's allegations are made on "information and belief," and the answers will depend on evidence produced during discovery.
    • Scope Questions: If the accused formulation uses a different disintegrant or polymer, the focus will shift to the doctrine of equivalents. This raises the question of whether an alternative excipient can be proven to be interchangeable, particularly as the patent specification presents data suggesting the superiority of croscarmellose sodium over other disintegrants for this specific application. (ʼ438 Patent, FIG. 1-2; Table 2).

V. Key Claim Terms for Construction

  • The Term: "croscarmellose sodium"
  • Context and Importance: This term recites a specific, well-defined chemical excipient. Its presence is a requirement of the independent claim. Practitioners may focus on this term because if the accused product uses any other disintegrant (e.g., sodium starch glycolate, crospovidone), Plaintiffs' case for literal infringement would fail, forcing reliance on the more complex doctrine of equivalents.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation (under Doctrine of Equivalents): A party might argue that other "superdisintegrants" perform the same function (rapidly breaking up the tablet) in the same way (swelling upon contact with water) to achieve the same result (fast drug release). The patent groups disintegrants together generally in the specification. (ʼ438 Patent, col. 13:54-56).
    • Evidence for a Narrower Interpretation: The patent provides specific experimental data comparing tablets made with croscarmellose sodium against tablets made with "low substituted hydroxypropyl cellulose." The data shows that croscarmellose sodium provides more consistent dissolution behavior, especially when granulation moisture levels vary. (ʼ438 Patent, FIG. 1 vs. FIG. 2; col. 24:44-59). A party could argue this evidence teaches that croscarmellose sodium is not merely an interchangeable example but was selected for its unique advantages in this specific formulation, potentially limiting the scope of equivalents.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon approval, Defendants will actively induce infringement by encouraging healthcare providers to prescribe and patients to use the Proposed ANDA Products. The basis for this allegation is the product's label, which will instruct users on how to take the infringing tablets. (Compl. ¶35, ¶40, ¶41).
  • Willful Infringement: The complaint does not use the term "willful," but it seeks a declaration that the case is "exceptional" under 35 U.S.C. § 285 and requests enhanced damages. (Compl., Prayer for Relief ¶f). Knowledge is premised on the ʼ438 Patent being listed in the FDA's Orange Book for XOFLUZA® and, at a minimum, on the filing of the complaint itself. (Compl. ¶30).

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

  • A central issue will be one of compositional identity: Does the confidential formulation in Defendants' ANDA contain the exact excipients—specifically "croscarmellose sodium" and one of the three claimed polymers—required for literal infringement of Claim 1? The outcome of this factual question, to be revealed in discovery, will determine the initial path of the litigation.
  • A key legal question will be the scope of equivalents: If the accused product uses a different disintegrant, can Plaintiffs prove it is an equivalent in light of the patent's own data highlighting the particular performance benefits of the claimed "croscarmellose sodium" over at least one alternative? The patent's specific teachings may create a high bar for proving interchangeability.