DCT

1:25-cv-00368

Calliditas Therap Ab v. Zydus Pharma USA Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00368, D. Del., 03/25/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendants conduct substantial business in the United States, including Delaware, through the sale of generic pharmaceutical products, and because Delaware will be a destination for the accused product upon FDA approval.
  • Core Dispute: Plaintiff alleges that Defendants' submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of Plaintiff's drug TARPEYO® constitutes an act of infringement of three patents covering oral dosage forms and methods of use for budesonide.
  • Technical Context: The technology concerns modified-release oral formulations of the corticosteroid budesonide designed to treat primary immunoglobulin A nephropathy (IgAN), a progressive autoimmune kidney disease, by targeting drug delivery to the ileum.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendants' notification to Plaintiff of their ANDA filing, which included a Paragraph IV certification asserting non-infringement of U.S. Patent No. 11,896,719. The complaint notes that Defendants' notification letter did not address U.S. Patent Nos. 12,171,882 and 12,171,883, despite their listing in the FDA's Orange Book for TARPEYO®.

Case Timeline

Date Event
2022-01-24 Earliest Priority Date for ’719, ’882, and ’883 Patents
2024-02-13 U.S. Patent No. 11,896,719 Issued
2024-12-24 U.S. Patent No. 12,171,882 Issued
2024-12-24 U.S. Patent No. 12,171,883 Issued
2025-02-12 Date of Defendants’ ANDA Notice Letter to Plaintiff
2025-03-25 Complaint Filing Date

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

U.S. Patent No. 11,896,719 - “Pharmaceutical Compositions,” issued February 13, 2024

The Invention Explained

  • Problem Addressed: The patent describes IgA nephropathy (IgAN) as a serious autoimmune kidney disease whose pathogenesis originates in the ileum, the final section of the small intestine. It notes that conventional treatments, such as high doses of systemic corticosteroids, are associated with a wide range of adverse events and do not address the underlying cause of the disease. The patent identifies a need for new treatments that deliver an immunosuppressive agent locally to the ileum to act on the lymphatic tissue (Peyer's patches) where the disease process begins, thereby avoiding undesirable systemic side effects (’719 Patent, col. 1:21-3:41).
  • The Patented Solution: The invention is a method of treating IgAN by administering an oral budesonide composition engineered for modified release. The composition is designed to pass through the stomach and upper intestine intact and release the active ingredient predominantly in the lower small intestine, particularly the ileum. This targeted delivery is achieved by a formulation that satisfies a specific three-part in vitro dissolution profile, ensuring minimal drug release in acidic conditions and controlled release in the pH conditions of the lower gastrointestinal tract (’719 Patent, Abstract; col. 3:42-58).
  • Technical Importance: This targeted-release approach is presented as a way to concentrate a therapeutic agent at the site of disease origin, potentially increasing efficacy while minimizing the systemic exposure and associated side effects common to conventional oral steroid therapies (’719 Patent, col. 2:25-41).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶42-43).
  • The essential elements of Claim 1 are:
    • A method of treating IgA nephropathy.
    • The method comprises identifying a pharmaceutically acceptable composition of budesonide that meets specific criteria in a standard in vitro dissolution test.
    • Criterion (a): No more than about 10% of the budesonide is released into an acidic medium (pH approx. 1.2) within about 120 minutes.
    • Criterion (b): No more than about 10% of the budesonide is released into a "pharmaceutically-relevant dissolution medium" within about 30 minutes.
    • Criterion (c): At least about 70% of the budesonide is released into the "pharmaceutically-relevant dissolution medium" within about 120 minutes.
    • The method then comprises administering said composition to a patient in need of treatment.

U.S. Patent No. 12,171,882 - “Pharmaceutical Compositions,” issued December 24, 2024

The Invention Explained

  • Problem Addressed: As a continuation of the application leading to the ’719 Patent, this patent addresses the same technical problem: the need for an effective, localized treatment for IgAN that targets the ileum to reduce the formation of pathogenic immune complexes while avoiding the adverse effects of systemic immunosuppression (’882 Patent, col. 1:21-3:40).
  • The Patented Solution: This invention also claims a method of treating IgAN by administering a modified-release budesonide composition. Claim 1 provides greater structural detail than the asserted claim of the '719 Patent, specifying a formulation of budesonide-containing cores coated with a particular "extended release pharmaceutically-acceptable polymeric blend" (containing ethylcellulose and hydroxypropylmethyl cellulose in specific ratios), which are then placed in a capsule with an enteric coating. This specific structure is designed to produce a dissolution profile that targets the ileum (’882 Patent, Abstract; col. 62:7-21).
  • Technical Importance: By defining the composition's physical structure in addition to its functional dissolution profile, the invention provides a specific technical means for achieving the desired targeted drug delivery to the site of IgAN pathogenesis (’882 Patent, col. 3:41-58).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶53-54).
  • The essential elements of Claim 1 are:
    • A method of treating IgA nephropathy by administering a specific pharmaceutical composition.
    • The composition comprises budesonide cores coated with an extended release polymeric blend containing about 47-56 wt. % ethylcellulose and about 22-32 wt. % hydroxypropylmethyl cellulose.
    • The coated cores are in a capsule that has an enteric coating.
    • The final composition meets a three-part in vitro release profile at a paddle speed of 100 rpm.
    • The subject is administered a daily dose of about 16 mg of budesonide.

U.S. Patent No. 12,171,883 - “Pharmaceutical Compositions,” issued December 24, 2024

Technology Synopsis

This patent is also in the same family and directed to pharmaceutical compositions for treating IgAN. The invention is a specific oral dosage form of budesonide, defined by its structural components, including cores with an extended-release polymeric blend encapsulated within an enterically coated capsule, which achieves a controlled release profile targeted to the lower intestine (’883 Patent, Abstract; col. 1:11-17).

Asserted Claims

The complaint asserts at least independent claim 1 (Compl. ¶64-65).

Accused Features

The complaint alleges that Defendants' ANDA Product is a 4 mg delayed-release capsule of budesonide that is bioequivalent to Plaintiff's TARPEYO® product and, when used as directed by its proposed label to treat IgAN, will meet the limitations of the claimed composition (Compl. ¶1, 37, 65).

III. The Accused Instrumentality

Product Identification

The accused instrumentality is Defendants' submission of Abbreviated New Drug Application (ANDA) No. 218685 to the FDA, which seeks approval to market and sell 4 mg delayed-release capsules of budesonide (Compl. ¶1). This is a proposed generic version of Plaintiff's TARPEYO® drug (Compl. ¶2).

Functionality and Market Context

The complaint alleges that by filing the ANDA, Defendants have represented to the FDA that their proposed product has the same active ingredient, dosage form, administration route, and strength as TARPEYO® (Compl. ¶37). It is further alleged that the product is intended to be bioequivalent to TARPEYO® and will be marketed for the same indication: "to reduce the loss of kidney function in adults with primary immunoglobulin A nephropathy (IgAN)" (Compl. ¶33, 37). The act of infringement alleged is a statutorily defined one under 35 U.S.C. § 271(e)(2)(A), where the submission of an ANDA for a drug claimed in a patent is an act of infringement for jurisdictional purposes (Compl. ¶42). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

11,896,719 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating IgA nephropathy...comprising...administering said composition to a patient with IgA nephropathy in need of said treatment... Defendants seek approval to market their ANDA Product for the treatment of IgAN, and the product's proposed label will instruct physicians and patients to administer it for this purpose. ¶33, 37 col. 6:50-51, col. 7:8-10
...identifying a pharmaceutically acceptable composition...comprising budesonide... Defendants' ANDA Product is an oral dosage form containing the active ingredient budesonide. ¶1, 37 col. 6:52-55
...which composition fulfils the following requirements in a standard in vitro...dissolution test... (a)...(b)...(c) The complaint alleges on information and belief that because the ANDA Product is represented as bioequivalent to TARPEYO®, it will necessarily meet the specific three-part dissolution profile required by the claim. ¶37, 43 col. 6:55-col. 7:7

12,171,882 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating IgA nephropathy in a subject in need thereof, comprising administering to the subject a pharmaceutical composition... The proposed label for the ANDA Product will instruct its administration to patients for the treatment of IgAN. ¶33, 37, 54 col. 62:3-6
...wherein the...composition comprises one or more cores comprising budesonide...coated with an extended release pharmaceutically-acceptable polymeric blend...administered as a capsule that comprises an enteric coating... The ANDA product is alleged to be a generic equivalent of TARPEYO® delayed-release capsules and therefore embodies the specific coated-core-in-capsule structure recited in the claim. ¶1, 37, 54 col. 62:7-21
...wherein the pharmaceutical composition meets the following release profile... (a)...(b)...(c) On information and belief, the ANDA Product is bioequivalent to TARPEYO® and its formulation is alleged to satisfy the claimed in vitro dissolution requirements. ¶37, 54 col. 62:22-44
...wherein the subject is administered a daily dose of about 16 mg of budesonide. The proposed product label for the ANDA Product will instruct physicians on a dosage regimen that includes a 16 mg daily dose, consistent with the TARPEYO® label. ¶37, 54 col. 62:45-47
  • Identified Points of Contention:
    • Scope Questions: Defendants' Paragraph IV letter for the ’719 Patent asserts non-infringement, suggesting a central dispute will be whether the specific formulation and dissolution characteristics of the Zydus product fall within the scope of the patent claims (Compl. ¶38). This raises the question of whether any differences in excipients, manufacturing processes, or resulting release profiles between the Zydus product and the claimed invention are sufficient to place it outside the literal scope of the claims or the doctrine of equivalents.
    • Technical Questions: A key technical question will be whether Defendants’ ANDA product actually meets the multi-part dissolution profiles claimed in the patents under the specified test conditions. The complaint's infringement theory rests on the allegation of bioequivalence, but the dispositive evidence will come from a direct comparison of the dissolution data for the Zydus product against the numeric limitations recited in the claims.

V. Key Claim Terms for Construction

  • The Term: "pharmaceutically-relevant dissolution medium" (’719 Patent, Claim 1)

    • Context and Importance: This term defines the environment for the key dissolution limitations (b) and (c) that control the targeted release. Its scope is critical, as the dissolution rate of the formulation can vary significantly depending on the pH and composition of the test medium.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification defines the term broadly as "any such medium that simulates dissolution and release in the small intestine or a relevant part thereof" and provides a list of non-limiting examples, including phosphate buffer media at pH 6.2, 6.8, 7.2, or 7.5, as well as Level 1 Fasted State Simulated Intestinal Fluid (FaSSIF) at pH 6.5 (’719 Patent, col. 7:11-24).
      • Evidence for a Narrower Interpretation: The detailed examples in the patent demonstrate the invention's performance in a specific medium: "50 mM Sodium Phosphate Buffer, pH 6.8, with Tween 80" (’719 Patent, col. 35:29-35). A party could argue the claims should be interpreted in light of these specific working examples.

  • The Term: "extended release pharmaceutically-acceptable polymeric blend" (’882 Patent, Claim 1)

    • Context and Importance: Claim 1 of the ’882 Patent defines this blend by its constituent polymers (ethylcellulose and hydroxypropylmethyl cellulose) and their relative weight percentages ("about 47 wt. % to about 56 wt. %" and "about 32 wt. % to about 22 wt. %"). Literal infringement depends on whether the Zydus formulation contains a blend meeting this structural definition.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The use of the term "about" for the weight percentages suggests the claim is not limited to the precise numerical ranges but encompasses formulations with reasonably similar compositions that perform in the same way to achieve the same result. The specification describes the function of the blend as controlling the release rate, which may support arguments for equivalence for different but functionally similar blends (’882 Patent, col. 27:3-21; Claim 1).
      • Evidence for a Narrower Interpretation: The claim recites specific polymers and numerical ranges. The patent's detailed Example 1 provides a precise formulation where the blend comprises "about 27.3 wt. % HPMC" and "about 51.8 wt. % ethylcellulose," which could be used to argue for a narrower construction of the claimed ranges, limiting the scope of "about" (’882 Patent, col. 34:20-25).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement, stating that upon FDA approval, Defendants will intentionally encourage direct infringement by marketing their ANDA product with a label that instructs physicians and patients to administer it for the patented method of treating IgAN (Compl. ¶46, 57, 68). The complaint also pleads contributory infringement, alleging Defendants know the product is especially adapted for an infringing use and has no substantial non-infringing use (Compl. ¶47, 58, 69).
  • Willful Infringement: The complaint alleges that Defendants had knowledge of the patents-in-suit prior to filing their ANDA, based on the patents’ listing in the FDA Orange Book and the statutory requirement for Defendants to address those patents in their ANDA submission (Compl. ¶50, 61, 72). Plaintiff requests that the case be found "exceptional" under 35 U.S.C. § 285, which is the basis for an award of attorneys' fees (Compl. ¶51, 62, 73).

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

  • A central issue will be one of technical performance: Does the Zydus ANDA product, when tested according to the protocols specified in the patents, exhibit a dissolution profile that falls within the numerical limitations of the asserted method claims, or is it sufficiently different to be non-infringing?
  • A key question of claim scope will be whether the claims, which are defined by a combination of functional (dissolution profile) and structural (polymeric blend composition) limitations, can be interpreted to cover Defendants' proposed generic product while remaining valid over prior art related to other modified-release budesonide formulations.
  • An evidentiary question will be one of intent for inducement: Assuming direct infringement by users is established, what evidence will demonstrate that Defendants' proposed product label and marketing materials would actively encourage physicians and patients to perform the steps of the claimed methods with the specific intent required for induced infringement?