DCT

1:25-cv-01280

Bayer Healthcare Pharma Inc v. Macleods Pharma Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-01280, D. Del., 02/25/2026
  • Venue Allegations: Venue is alleged to be proper as to Macleods Pharma USA, Inc. because it is incorporated in Delaware. Venue is alleged to be proper as to Macleods Pharmaceuticals Ltd., a foreign corporation, based on its contacts with the United States and its consent to personal jurisdiction in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s filing of an Abbreviated New Drug Application (ANDA) for a generic version of the drug KERENDIA® (finerenone) constitutes an act of infringement of a patent covering a specific crystalline form of the finerenone compound.
  • Technical Context: The technology relates to the pharmaceutical compound finerenone, a non-steroidal mineralocorticoid receptor antagonist used to treat chronic kidney disease and heart failure, and specifically to a stable crystalline form (polymorph) of that compound suitable for commercial drug products.
  • Key Procedural History: The patent-in-suit, RE49,826, is a reissue of U.S. Patent No. 10,336,749. This litigation was initiated under the Hatch-Waxman Act following Plaintiff’s receipt of Defendant’s Paragraph IV Notice Letters, which asserted that the patent is not infringed and/or is invalid.

Case Timeline

Date Event
2015-08-21 Priority Date for RE49,826 Patent
2019-07-02 Original U.S. Patent No. 10,336,749 Issued
2021-07-09 FDA Approval for KERENDIA® (NDA No. 215341)
2024-02-06 U.S. Patent No. RE49,826 Issued
2025-09-09 Macleods Sends First Paragraph IV Notice Letter
2026-02-02 Macleods Sends Second Paragraph IV Notice Letter
2026-02-25 Complaint Filing Date

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

U.S. Patent No. RE49,826 - Method for the preparation of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1-6-naphthyridine-3-carboxamide and the purification thereof for use as an active pharmaceutical ingredient

  • Patent Identification: U.S. Patent No. RE49,826, "Method for the preparation of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1-6-naphthyridine-3-carboxamide and the purification thereof for use as an active pharmaceutical ingredient," issued February 6, 2024 (the "RE’826 Patent").

The Invention Explained

  • Problem Addressed: The patent's background describes prior methods for synthesizing the finerenone compound as being "research scale" syntheses that were unsuitable for large-scale industrial production (RE’826 Patent, col. 5:46-58). These prior methods allegedly suffered from low overall yield, the need for very high dilution and excessive reagents, and required "laborious" chromatographic purifications that are costly and difficult to scale (RE’826 Patent, col. 5:51-58).
  • The Patented Solution: The patent discloses an improved, "industrially practicable synthesis" that produces the finerenone compound in high yield and purity without requiring chromatographic purification of intermediates (RE’826 Patent, col. 5:59-67; RE’826 Patent, col. 6:62-67). The patent also identifies and characterizes a specific, stable crystalline form of the final compound, designated "polymorph I," which is described as having reproducible bioavailability and a defined melting point, making it suitable for formulation into tablets (RE’826 Patent, col. 13:56-65).
  • Technical Importance: The invention provides a method to produce a therapeutically important compound at an industrial scale and, critically, claims a specific solid-state form (polymorph) of that compound, which is a key consideration for ensuring consistency, stability, and regulatory approval of a final drug product (RE’826 Patent, col. 5:59-67).

Key Claims at a Glance

The complaint alleges infringement of "one or more claims" (Compl. ¶55). Based on the nature of the dispute concerning a generic drug product, independent claim 14, which covers a specific crystalline form of the compound, is a representative asserted claim.

  • Independent Claim 14:
    • A compound of the formula (I) in crystalline form of polymorph I,
    • wherein the x-ray diffractogram of the compound exhibits peak maxima of the 2 theta angle at 8.5, 14.1, and 19.0.

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is the generic finerenone tablet product described in Macleods's Abbreviated New Drug Application (ANDA) No. 220747 (Compl. ¶1). The product is intended to be marketed in 10 mg, 20 mg, and 40 mg dosages (Compl. ¶14; Compl. ¶41; Compl. ¶42).

Functionality and Market Context

  • The product is a generic version of Bayer's branded drug, KERENDIA® (Compl. ¶1). KERENDIA® contains the active ingredient finerenone and is a non-steroidal mineralocorticoid receptor antagonist (nsMRA) indicated for treating adult patients with chronic kidney disease associated with type 2 diabetes, as well as certain types of heart failure (Compl. ¶32).
  • Macleods's filing of its ANDA seeks FDA approval to market this generic version before the expiration of the RE’826 Patent, which is listed in the FDA's "Orange Book" as covering KERENDIA® (Compl. ¶1; Compl. ¶34). The act of filing the ANDA with a "Paragraph IV Certification" is the statutory basis for this infringement action under the Hatch-Waxman Act (Compl. ¶53).

No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not contain a detailed claim chart. The infringement allegation is a statutory one under 35 U.S.C. § 271(e)(2)(A), where the filing of the ANDA is an artificial act of infringement if the product, once approved and marketed, would infringe (Compl. ¶53). The core allegation is that Macleods's ANDA product is a generic equivalent of KERENDIA® and will therefore possess the characteristics of the compound claimed in the RE’826 Patent (Compl. ¶1; Compl. ¶34).

RE’826 Patent Infringement Allegations

Claim Element (from Independent Claim 14) Alleged Infringing Functionality Complaint Citation Patent Citation
A compound of the formula (I) The Macleods ANDA product contains finerenone, the compound of formula (I), as its active pharmaceutical ingredient. ¶1; ¶41 col. 5:20-39
in crystalline form of polymorph I, The complaint's general allegation that the Macleods ANDA product will infringe one or more claims of the patent implies that the product is formulated using the specific "polymorph I" crystalline structure. ¶53; ¶55 col. 13:60-65
wherein the x-ray diffractogram of the compound exhibits peak maxima of the 2 theta angle at 8.5, 14.1, and 19.0. It is alleged that the crystalline form of finerenone in Macleods's ANDA product will, upon testing, exhibit the characteristic X-ray diffraction peaks required by the claim. ¶53; ¶55 col. 14:40-44
  • Identified Points of Contention:
    • Polymorphic Identity: A central question will be whether the crystalline form of finerenone in Macleods's proposed generic product is, in fact, the "polymorph I" claimed in the RE’826 Patent. The analysis will focus on whether Macleods's product exhibits the specific X-ray powder diffraction (XRPD) peaks recited in the claim. Generic manufacturers frequently attempt to design around polymorph patents by developing a different, non-infringing crystalline form or an amorphous version of the active ingredient.
    • Evidentiary Issues: The complaint does not and is not required to provide empirical evidence, such as analytical test data, of Macleods's ANDA product. A key aspect of the case will be the discovery process, through which Bayer will seek to obtain and test samples of Macleods's product to determine its physical characteristics and prove that it meets the claim limitations.

V. Key Claim Terms for Construction

  • The Term: "crystalline form of polymorph I"
  • Context and Importance: The definition of this term is dispositive for the product claims. If Macleods's product does not meet the definition of "polymorph I," it will not infringe claims like claim 14. Practitioners may focus on this term because the scope of the claim—and thus the infringement analysis—depends entirely on what structural and physical characteristics are required to qualify as this specific polymorph.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A party could argue that the term should be defined primarily by the explicit limitations in the asserted claim. For claim 14, this would mean a crystalline compound of formula (I) is "polymorph I" if its XRPD pattern shows peaks at 8.5, 14.1, and 19.0 (± measurement error), regardless of other physical properties.
    • Evidence for a Narrower Interpretation: A party could argue that "polymorph I" is a specific structure defined by the full set of characterization data provided in the specification. This includes a more extensive list of XRPD peaks (RE’826 Patent, col. 14:41-44), specific band maxima in IR and Raman spectra (RE’826 Patent, col. 14:66-68; RE’826 Patent, col. 15:19-22), and a defined melting point of 252° C (RE’826 Patent, col. 13:64-65). Under this view, a form that meets the three peaks in claim 14 but deviates from other specified characteristics would not be "polymorph I."

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon FDA approval, Macleods will contribute to and induce infringement by healthcare professionals and patients who will use the generic product (Compl. ¶64). The basis for this allegation is that Macleods intends for its product to be used in accordance with its FDA-approved labeling, which will inherently involve administering the patented compound (Compl. ¶64).
  • Willful Infringement: The complaint alleges that Macleods has acted with "full knowledge of the RE'826 Patent" and lacks a reasonable basis for its belief of non-infringement or invalidity (Compl. ¶57). This knowledge is evidenced by Macleods's sending of the Paragraph IV Notice Letters (Compl. ¶40; Compl. ¶42).

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

This case appears to center on classic issues in pharmaceutical patent litigation under the Hatch-Waxman Act. The key questions for the court will likely be:

  • A core question will be one of polymorphic identity: Does the finerenone active ingredient in Macleods's proposed generic product, as described in its ANDA, exist in the specific "crystalline form of polymorph I" as defined by the asserted patent claims? The outcome will likely depend on expert testimony interpreting analytical data (e.g., XRPD) from Macleods's product.
  • A second central issue will be patent validity: Can Macleods prove by clear and convincing evidence that the patent's claims to this specific polymorph are invalid, for instance, by showing they were obvious over prior art or not enabled by the patent's disclosure, as it contended in its Paragraph IV notice? (Compl. ¶44).
  • A final question will be one of claim construction: How will the court define the scope of the term "crystalline form of polymorph I"? Will it be limited to a form that meets all characterization data in the specification, or will it be defined more broadly by the specific XRPD peaks recited in the independent claims?
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