DCT

1:25-cv-00368

Calliditas Therap Ab v. Zydus Pharma USA Inc

Log In
Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00368, D. Del., 10/31/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware based on Defendants' sales of generic drug products within the district, purposeful availment of the benefits of the state, and prior consent to personal jurisdiction in the district. For the foreign defendant, Zydus Lifesciences, venue is also alleged on the basis of its status as a foreign company.
  • Core Dispute: Plaintiff alleges that Defendants' submission of an Abbreviated New Drug Application (ANDA) for a generic version of Plaintiff's TARPEYO® (budesonide) product infringes four patents related to specific oral dosage formulations and methods of use for treating IgA nephropathy.
  • Technical Context: The technology involves delayed-release oral formulations of the corticosteroid budesonide engineered to target the ileum, a specific region of the small intestine, to treat the underlying causes of a progressive autoimmune kidney disease.
  • Key Procedural History: The action was initiated under the Hatch-Waxman Act following Defendants' submission of ANDA No. 218685 to the U.S. Food and Drug Administration. The complaint alleges Defendants provided a Paragraph IV Certification asserting non-infringement of U.S. Patent Nos. 11,896,719 and 12,311,057. The complaint further alleges that Defendants' notice 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, ’883, and ’057 Patents
2024-02-13 U.S. Patent No. 11,896,719 Issues
2024-12-24 U.S. Patent No. 12,171,882 Issues
2024-12-24 U.S. Patent No. 12,171,883 Issues
2025-02-12 Zydus sends Notice Letter regarding ’719 Patent
2025-05-27 U.S. Patent No. 12,311,057 Issues
2025-09-15 Zydus sends Notice Letter regarding ’057 Patent
2025-10-31 Amended Complaint Filed

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

U.S. Patent No. 11,896,719 - *"Pharmaceutical Compositions"*

The Invention Explained

  • Problem Addressed: The patent describes IgA nephropathy (IgAN) as a serious autoimmune kidney disease whose pathogenesis begins in the ileum, the final part of the small intestine. It notes that systemic corticosteroid treatments carry a wide range of adverse side effects, creating a need for a new treatment that can act locally within the ileum to address the disease at its origin without causing such effects (’719 Patent, col. 1:24-41, col. 2:25-41).
  • The Patented Solution: The invention provides a method of treating IgAN using an oral budesonide composition engineered for modified release. The composition uses a multi-layered coating system—including an outer enteric (delayed-release) coating and an inner extended-release coating on budesonide-containing cores—designed to prevent drug release in the stomach and upper intestine, and to release the budesonide payload predominantly in the distal ileum to act on gut lymphatic tissue (Peyer's patches) (’719 Patent, Abstract; col. 2:47-60). This targeted release is defined by a specific, three-part in vitro dissolution profile that the composition must satisfy under standardized testing conditions (’719 Patent, col. 6:50-col. 7:8).
  • Technical Importance: This targeted delivery approach is designed to treat the underlying cause of IgAN by reducing the formation of pathogenic IgA molecules where they originate, thereby aiming to limit systemic drug exposure and avoid the undesirable side effects of conventional, high-dose systemic corticosteroids (’719 Patent, col. 2:55-60; col. 4:32-46).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 (Compl. ¶44).
  • Essential elements of independent claim 1 include:
    • A method of treating IgA nephropathy by administering a pharmaceutical composition comprising one or more cores containing budesonide.
    • The cores are coated with an extended-release polymeric blend comprising specific weight percentages of ethylcellulose (about 51.8 wt. %) and hydroxypropylmethyl cellulose (about 27.3 wt. %).
    • The blend is present in an amount of from about 5 wt. % to about 18 wt. % of the total coated core weight.
    • The composition is administered as a capsule comprising an enteric coating in an amount of from about 34 mg to about 46 mg per capsule.
    • The composition must meet a three-part in vitro release profile under specified USP<711> test conditions.
    • The subject is administered a daily dose of about 16 mg of budesonide.

U.S. Patent No. 12,171,882 - *"Pharmaceutical Compositions"*

The Invention Explained

  • Problem Addressed: As a continuation of the application that led to the ’719 Patent, this patent addresses the same technical problem: the need for a targeted treatment for IgA nephropathy (IgAN) that acts locally in the ileum to minimize the significant adverse effects associated with systemic corticosteroid therapies (’882 Patent, col. 1:24-41, col. 2:36-41).
  • The Patented Solution: The patent claims a method of treating IgAN by administering an oral budesonide formulation with a specific modified-release profile. The formulation consists of coated cores within an enteric-coated capsule, designed to deliver the active ingredient to the ileum region of the small intestine (’882 Patent, Abstract; col. 2:47-60). The claims define the core's extended-release coating more broadly in terms of polymer function—a "water-insoluble polymer" and a "pore-forming polymer"—rather than by specific chemical names (’882 Patent, col. 63:60-64:12).
  • Technical Importance: The approach aims to provide a localized immunosuppressive effect on the gut tissue where pathogenic IgA antibodies are produced, thereby treating the root cause of IgAN while reducing the systemic side effects common to conventional therapies (’882 Patent, col. 2:55-60; col. 4:32-46).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 (Compl. ¶55).

  • Essential elements of independent claim 1 include:

    • A method of treating IgA nephropathy by administering a composition with cores comprising budesonide.
    • The cores are coated with a blend of a "water-insoluble polymer" and a "pore-forming polymer" in specified weight percentage ranges.
    • The blend is present in an amount of from 5 wt. % to 18 wt. % of the total coated core weight.
    • The composition is in a capsule with an enteric coating present in an amount of from 34 mg to 46 mg.
    • The composition must satisfy a specific three-part in vitro release profile under defined test conditions.
    • The subject is administered a daily dose of about 16 mg of budesonide.

  • Multi-Patent Capsule:

    • Patent Identification: U.S. Patent No. 12,171,883, "Pharmaceutical Compositions," issued December 24, 2024.
    • Technology Synopsis: This patent, from the same family as the patents above, claims a pharmaceutical composition, rather than a method of use. The composition comprises budesonide-containing cores with a specific multi-layer coating system designed for modified release to the ileum, intended for the treatment of IgA nephropathy (’883 Patent, Abstract; col. 2:47-60).
    • Asserted Claims: At least independent claim 1 is asserted (Compl. ¶66).
    • Accused Features: The complaint alleges that Defendants' ANDA Product is a pharmaceutical composition that meets the structural and functional limitations of the asserted claims (Compl. ¶67).

  • Multi-Patent Capsule:

    • Patent Identification: U.S. Patent No. 12,311,057, "Pharmaceutical Compositions," issued May 27, 2025.
    • Technology Synopsis: This patent claims a method of treating IgA nephropathy by administering an oral budesonide composition. The claims recite a specific multi-component extended-release coating and a defined in vitro dissolution profile, consistent with the family's technology of targeting the ileum to provide local immunosuppression (’057 Patent, Abstract; col. 2:47-60).
    • Asserted Claims: At least independent claim 1 is asserted (Compl. ¶77).
    • Accused Features: The complaint alleges that the use of Defendants' ANDA Product according to its product label for the treatment of IgA nephropathy will infringe the claimed method (Compl. ¶78).

III. The Accused Instrumentality

Product Identification

Defendants' Abbreviated New Drug Application ("ANDA") Product, identified as ANDA No. 218685, which is a proposed generic version of Plaintiff's TARPEYO® brand drug (Compl. ¶1).

Functionality and Market Context

The ANDA Product is described as a 4 mg delayed-release capsule of budesonide (Compl. ¶1). The complaint alleges that by filing the ANDA, Defendants have represented to the FDA that their product has the same active ingredient, dosage form, route of administration, and strength as TARPEYO®, and that it is bioequivalent (Compl. ¶38). The product is intended for the same approved indication as TARPEYO®: to reduce the loss of kidney function in adults with primary immunoglobulin A nephropathy (IgAN) (Compl. ¶34, ¶38). The product is positioned to compete directly with TARPEYO® in the U.S. market upon receiving FDA approval (Compl. ¶37). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint alleges that Defendants' ANDA Product, and its use as directed by its label, will infringe the asserted patents because the product is necessarily a copy of the TARPEYO® reference drug and must therefore possess the same claimed characteristics (Compl. ¶38, 45, 56). The complaint does not contain a detailed chart mapping specific features of the accused product to the claim limitations.

U.S. Patent No. 11,896,719 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 comprising one or more cores comprising budesonide... | The use of Defendants' ANDA product is alleged to be a method of treating IgA nephropathy by administering the claimed composition. - | ¶45 | col. 63:58-62 |
| wherein the one or more cores are coated with an extended release pharmaceutically-acceptable polymeric blend comprising ethylcellulose in an amount of about 51.8 wt. % ... and hydroxypropylmethyl cellulose in an amount of about 27.3 wt. %... | The ANDA product is alleged to contain cores with the specified coated polymeric blend. - ¶45 | col. 34:20-25 |
| wherein the extended release pharmaceutically-acceptable polymeric blend is present in an amount of from about 5 wt. % to about 18 wt. % of the total coated core weight... | The ANDA product is alleged to contain the polymeric blend within the specified weight percentage range. - ¶45 | col. 28:46-49 |
| wherein the pharmaceutical composition is orally administered as a capsule that comprises an enteric coating in an amount of from about 34 mg to about 46 mg per capsule... | The ANDA product is alleged to be a capsule with an enteric coating of the specified amount. - ¶45 | col. 34:45-49 |
| wherein the pharmaceutical composition meets the following release profile in a standard in vitro USP<711> dissolution test... | The ANDA product is alleged to meet the specified three-part in vitro dissolution profile. - ¶45 | col. 64:13-41 |
| wherein the subject is administered a daily dose of about 16 mg of budesonide. | Use of the ANDA product as directed by its label is alleged to involve administering the specified daily dose. - ¶45 | col. 41:5-20 |

U.S. Patent No. 12,171,882 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 comprising one or more cores comprising budesonide... | The use of Defendants' ANDA product is alleged to be a method of treating IgA nephropathy by administering the claimed composition. - ¶56 | col. 63:51-55 |
| wherein the one or more cores are coated with an extended release pharmaceutically-acceptable polymeric blend comprising a water-insoluble polymer... and a pore-forming polymer... | The ANDA product is alleged to contain cores coated with a blend of polymers having the specified solubility characteristics. - ¶56 | col. 27:7-21 |
| wherein the extended release pharmaceutically-acceptable polymeric blend is present in an amount of from 5 wt. % to about 18 wt. % of the total coated core weight... | The ANDA product is alleged to contain the polymeric blend within the specified weight percentage range. - ¶56 | col. 28:46-49 |
| wherein the pharmaceutical composition is orally administered as a capsule that comprises an enteric coating in an amount of from about 34 mg to about 46 mg per capsule... | The ANDA product is alleged to be an enteric-coated capsule with the specified coating amount. - ¶56 | col. 34:45-49 |
| wherein the pharmaceutical composition meets the following release profile in a standard in vitro USP<711> dissolution test... | The ANDA product is alleged to meet the claimed three-part in vitro dissolution profile. - ¶56 | col. 65:1-21 |
| wherein the subject is administered a daily dose of about 16 mg of budesonide. | Use of the ANDA product as directed by its label is alleged to involve administering the specified daily dose. - ¶56 | col. 41:5-20 |

  • Identified Points of Contention:
    • Evidentiary Questions: The complaint's infringement theory rests on the assertion that the accused generic product is necessarily a copy of the patented TARPEYO® product. A central issue for the court will be whether the evidence obtained during discovery confirms that the precise formulation, polymer weight percentages, coating amounts, and, critically, the in vitro dissolution profile of Defendants' ANDA product actually meet the specific quantitative limitations recited in the asserted claims.
    • Scope Questions: The claims require a multi-part dissolution profile under specific "pharmaceutically-relevant" testing conditions. A potential point of contention is whether Defendants' product, even if shown to be bioequivalent in vivo, meets the specific numerical thresholds of the claimed in vitro test. This raises the question of whether minor variations in formulation could result in a product that is bioequivalent for FDA purposes but falls outside the literal scope of the claims' dissolution requirements.

V. Key Claim Terms for Construction

  • The Term: "pharmaceutically-relevant dissolution medium"
  • Context and Importance: This term is critical because infringement of the asserted claims in both the ’719 and ’882 Patents hinges on the composition meeting a specific dissolution profile when tested in this medium. The definition of this medium—including its precise pH, buffer system, and the optional presence of surfactants—will determine the conditions under which infringement is assessed. Practitioners may focus on this term because a narrow construction could limit the range of tests under which infringement can be proven, while a broader one could encompass more testing conditions.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification provides a functional definition, stating it includes "media which is suitable for use in an in vitro dissolution assay the results of which are indicative of in vivo release at the relevant part of the intestinal tract" (’719 Patent, col. 7:12-16). This language may support an argument that the term is not limited to specific examples but covers any medium that validly simulates conditions in the small intestine.
    • Evidence for a Narrower Interpretation: The specification provides specific examples of such media, including "a phosphate buffer medium at a pH of about 6.8" and "a Level 1 Fasted State Simulated Intestinal Fluid (FaSSIF) at a pH of about 6.5" (’719 Patent, col. 7:26-33). Parties may argue that the term should be limited to these disclosed examples or media with very similar properties.
  • The Term: "about"
  • Context and Importance: This term appears repeatedly in the asserted claims to qualify critical numerical values, such as the daily dose ("about 16 mg"), polymer weight percentages ("about 51.8 wt. %"), and dissolution release rates ("about 70%"). The scope of "about" will define the permissible range of deviation from these numbers. Infringement could turn on whether the measured values for Defendants' product, if not identical, are still close enough to be considered "about" the claimed value.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification provides an explicit definition, stating that "'about 10%' may mean ±10% about the number 10, which is anything between 9% and 11%" (’719 Patent, col. 32:65-col. 33:2). A party could cite this as evidence of the patentee's intent for the term to impart meaningful flexibility and encompass standard industry tolerances.
    • Evidence for a Narrower Interpretation: A party may argue that in the context of pharmaceutical formulations, where precision is key to achieving a specific release profile, "about" should be construed narrowly to reflect the precision implied by values carried out to a decimal place (e.g., "about 51.8 wt. %"). The argument could be that the patentee's reliance on a highly specific dissolution profile suggests that significant deviation from the recited component values was not contemplated.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all four patents-in-suit. The inducement allegation is based on the assertion that, upon FDA approval, Defendants will intentionally encourage infringement by physicians and patients who follow the instructions on the ANDA product's label, with knowledge of the patents (Compl. ¶48, 59, 70, 81). The contributory infringement allegation is based on the product being especially made for an infringing use with no substantial non-infringing uses (Compl. ¶49, 60, 71, 82).
  • Willful Infringement: The complaint alleges that Defendants had knowledge of the patents-in-suit prior to filing their ANDA (Compl. ¶52, 63, 74, 85). Based on this alleged pre-suit knowledge, the complaint asserts that this is an "exceptional case" and requests an award of attorneys' fees, which suggests a claim for willful infringement (Compl. ¶53, 64, 75, 86).

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

  • A central issue will be one of factual correspondence: As is common in ANDA litigation, the complaint makes infringement allegations based on the statutory requirement that the generic product be the same as the branded product. The key question for the court will be whether the specific formulation, component weight percentages, coating amounts, and in vitro dissolution profile of Defendants' actual ANDA product, as revealed in discovery, fall within the precise numerical limitations of the asserted claims.
  • A second core issue will be one of definitional scope: The construction of the term "about" will be critical in determining the boundaries of the claims' quantitative limitations. The outcome may depend on whether this term is interpreted broadly to encompass standard manufacturing tolerances or narrowly in light of the highly specific technical performance described in the patents.
  • Finally, a key procedural question relates to pre-suit conduct: The complaint's allegation that Defendants' initial notice letter failed to address two of the four patents-in-suit, despite their Orange Book listing, raises the question of how this will affect Defendants' potential defenses and Plaintiff's arguments regarding knowledge and willfulness.