DCT

1:25-cv-01281

Bayer Healthcare Pharma Inc v. MSN Pharma Inc

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-01281, D. Del., 10/20/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware because Defendant MSN Pharmaceuticals is a Delaware corporation, and Defendants MSN Laboratories and MSN Life Sciences are foreign corporations that have allegedly consented to personal jurisdiction in the district through prior litigation conduct and have systematic contacts with the state.
  • Core Dispute: Plaintiff alleges that Defendants' filing of an Abbreviated New Drug Application (ANDA) seeking to market a generic version of the drug KERENDIA® (finerenone) constitutes an act of infringement of a reissue patent covering methods for preparing and purifying the active pharmaceutical ingredient.
  • Technical Context: The technology at issue is a multi-step chemical synthesis and purification process for manufacturing finerenone, a non-steroidal mineralocorticoid receptor antagonist used for treating chronic kidney disease and heart failure.
  • Key Procedural History: The patent-in-suit is a reissue of U.S. Patent No. 10,336,749; claims 1-13 of the original patent are not part of the reissued patent. This litigation was initiated under the Hatch-Waxman Act following Defendants' submission of a Paragraph IV certification asserting that the patent-in-suit is invalid, unenforceable, and/or will not be infringed by their proposed generic product.

Case Timeline

Date Event
2015-08-21 RE'826 Patent Priority Date
2019-07-02 Original U.S. Patent No. 10,336,749 Issued
2021-07-09 FDA Approval for Bayer's KERENDIA® (NDA No. 215341)
2024-02-06 U.S. Reissue Patent No. RE49,826 Issued
2025-09-08 MSN Paragraph IV Notice Letter Sent
2025-09-15 Bayer Received MSN's Paragraph IV Notice Letter
2025-10-20 Complaint Filed

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

U.S. Reissue 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. Reissue 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 section describes prior "research scale synthesis" methods for the compound finerenone as being unsuitable for large-scale industrial manufacturing (RE'826 Patent, col. 1:46-51). These earlier methods allegedly suffered from low overall yield, the need for very high dilution, excessive use of reagents, and reliance on "laborious" and costly chromatographic purifications of intermediate compounds (RE'826 Patent, col. 1:51-58).
  • The Patented Solution: The patent discloses an "industrially practicable synthesis" designed to produce finerenone in high yield and purity without the need for chromatographic purification of intermediates (RE’826 Patent, col. 1:59-64, col. 2:62-67). The process involves a specific sequence of chemical reactions, culminating in a chiral separation and a final crystallization step designed to reproducibly yield a specific crystalline form of the compound, designated Polymorph I (RE’826 Patent, col. 14:1-24).
  • Technical Importance: The claimed invention provides a scalable and economically efficient manufacturing process for an active pharmaceutical ingredient, which is a critical step in making a drug commercially viable (RE’826 Patent, col. 1:59-64).

Key Claims at a Glance

  • The complaint alleges infringement of one or more claims without specifying which ones (Compl. ¶58). Independent claim 2 is representative of the asserted process claims.
  • Essential elements of independent claim 2 include:
    • A process for preparing the compound of formula (I) (finerenone).
    • The process comprises separating a racemic compound of formula (XIII) into its enantiomers.
    • The compound of formula (XIII) is prepared by reacting a compound of formula (XVIII) with an orthoester (XX).
  • The complaint does not explicitly reserve the right to assert dependent claims, but this is standard practice.

III. The Accused Instrumentality

Product Identification

Defendants' generic finerenone tablets (10 mg and 20 mg), as described in Abbreviated New Drug Application (ANDA) No. 220821 (the "MSN ANDA Product") (Compl. ¶1, ¶45).

Functionality and Market Context

The MSN ANDA Product is a generic version of Bayer's KERENDIA®, a non-steroidal mineralocorticoid receptor antagonist (nsMRA) (Compl. ¶1, ¶36). It is indicated for reducing the risk of kidney function decline, kidney failure, cardiovascular death, and heart failure hospitalization in certain adult patients (Compl. ¶36). The complaint alleges that upon FDA approval, Defendants intend to commercially manufacture, market, and sell the generic product in the United States (Compl. ¶17, ¶45).

IV. Analysis of Infringement Allegations

The complaint does not provide a claim chart or specific details of the manufacturing process described in MSN’s ANDA. The infringement allegation is statutory, based on the act of filing the ANDA under 35 U.S.C. § 271(e)(2)(A) (Compl. ¶56). Plaintiff alleges that the commercial manufacture, use, or sale of the MSN ANDA Product, if approved, would infringe one or more claims of the RE’826 Patent (Compl. ¶58). The core of the infringement theory is that the process MSN will use to manufacture its generic finerenone falls within the scope of the method claims of the RE’826 Patent.

No probative visual evidence provided in complaint.

  • Identified Points of Contention:
    • Factual Question: The central factual dispute will be whether the confidential manufacturing process detailed in MSN's ANDA submission practices each step of the asserted patent claims. This information is not public and will be a primary focus of discovery.
    • Scope Questions: A likely point of contention will be the scope of the process steps recited in the claims. For example, a question for the court may be whether a claim to "separating a racemic compound" is limited to the specific chiral separation techniques disclosed in the specification (e.g., Simulated Moving Bed chromatography) or if it covers any method of enantiomeric resolution that MSN might employ (RE’826 Patent, col. 13:6-14).
    • Technical Questions: The analysis will raise the question of whether MSN's synthesis pathway uses the specific chemical intermediates and reagents required by the claims. For instance, does MSN's process start with the compound of formula (XVIII) and react it with an orthoester (XX) to produce the compound of formula (XIII), as required by claim 2? The complaint does not provide evidence to answer this question.

V. Key Claim Terms for Construction

  • The Term: "separating a racemic compound of the formula (XIII) into its enantiomers" (from claim 2)
  • Context and Importance: This term defines the critical chiral resolution step that isolates the desired stereoisomer of the drug. The definition of "separating" will be crucial, as different methods of chiral resolution exist. Practitioners may focus on this term because the patent's specification describes a specific and efficient separation using Simulated Moving Bed (SMB) chromatography with a "Chiralpak AS-V" stationary phase, and a defendant may argue that the claim scope should be interpreted in light of these detailed embodiments (RE'826 Patent, col. 12:50-65).
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language "separating...into its enantiomers" does not, on its face, specify a particular technique. Plaintiff may argue this term should be given its plain and ordinary meaning, which could encompass any technique for resolving a racemic mixture, such as diastereomeric crystallization or other forms of chiral chromatography.
    • Evidence for a Narrower Interpretation: The specification emphasizes the advantages of using SMB or Varicol techniques for the separation on a multi-ton scale (RE’826 Patent, col. 13:6-14). A defendant might argue that these detailed descriptions of a specific, highly effective method limit the scope of the more general term "separating" used in the claims.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon approval of the ANDA, Defendants will actively induce and contribute to the infringement of the RE’826 Patent (Compl. ¶59, ¶67). The inducement allegation is based on the assertion that Defendants know of the patent and intend for healthcare professionals and patients to use a product that will be manufactured by an infringing process (Compl. ¶67).
  • Willful Infringement: The complaint alleges that Defendants have acted with full knowledge of the RE’826 Patent, citing the Paragraph IV certification as evidence of this knowledge (Compl. ¶44, ¶60). It further alleges that Defendants lack a reasonable basis for believing their proposed generic product would not infringe, thereby supporting a claim for willful infringement (Compl. ¶60).

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

  • A primary evidentiary question will be one of process identity: What are the specific steps, reagents, and intermediates of the manufacturing process described in MSN’s confidential ANDA, and does that process meet every limitation of at least one asserted claim of the RE’826 Patent?
  • A central legal issue will be one of claim scope: How broadly will the court construe the key process limitations, such as "separating a racemic compound"? The outcome may depend on whether the claims are interpreted to cover any method of achieving the recited step or are limited by the specific, highly detailed embodiments disclosed in the patent's specification.
  • A key defense to monitor, given the patent's status as a reissue, will be intervening rights: Does MSN have a viable defense under 35 U.S.C. § 252? This will depend on whether the asserted claims were substantively broadened from the original patent and whether MSN can establish that it made substantial preparations to practice the claimed process before the reissue date.