DCT

1:25-cv-00043

Acerta Pharma BV v. MSN Pharma Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00043, D. Del., 01/10/2025
  • Venue Allegations: Venue is alleged to be proper as to MSN Pharmaceuticals because it is a Delaware corporation and thus resides in the district. Venue is alleged as to MSN Laboratories, a foreign corporation, on the basis that it is subject to personal jurisdiction in the district.
  • Core Dispute: Plaintiff alleges that Defendant's submission of an Abbreviated New Drug Application (ANDA) to market a generic version of the cancer drug CALQUENCE® constitutes an act of infringement of two patents covering methods of using the drug and specific crystalline forms of its active ingredient.
  • Technical Context: The technology relates to kinase inhibitors, specifically Bruton's tyrosine kinase (BTK) inhibitors, used in oncology for the treatment of B-cell malignancies like chronic lymphocytic leukemia.
  • Key Procedural History: The litigation was triggered by a notice letter dated November 27, 2024, in which MSN informed Plaintiffs of its ANDA filing and its Paragraph IV Certification asserting that the patents-in-suit are invalid and/or not infringed. The complaint notes that MSN's letter did not contest infringement of the asserted claims on any basis other than alleged invalidity.

Case Timeline

Date Event
2014-01-21 U.S. Patent No. 10,272,083 Priority Date
2015-12-28 U.S. Patent No. 11,059,829 Priority Date
2019-04-30 U.S. Patent No. 10,272,083 Issued
2021-07-13 U.S. Patent No. 11,059,829 Issued
2024-11-27 MSN's Paragraph IV Notice Letter Sent to Plaintiffs
2025-01-10 Complaint Filed

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

U.S. Patent No. 10,272,083 - "Methods of Treating Chronic Lymphocytic Leukemia and Small Lymphocytic Leukemia Using a BTK Inhibitor," issued April 30, 2019

The Invention Explained

  • Problem Addressed: The patent's background describes a need for less toxic and more effective treatments for chronic lymphocytic leukemia (CLL) and small lymphocytic leukemia (SLL), as standard therapies are associated with toxicities and may fail to eradicate malignant B-cells that are protected within microenvironments like bone marrow and lymph nodes (’083 Patent, col. 1:40-50, col. 2:1-6).
  • The Patented Solution: The invention provides a specific method of treatment involving the oral administration of a particular Bruton's tyrosine kinase (BTK) inhibitor, acalabrutinib (identified as the compound of Formula (II)), at a precise dosage regimen of 100 mg twice daily to treat patients with CLL or SLL (’083 Patent, col. 2:10-18, col. 2:35-37). The complaint provides a chemical diagram of this compound (Compl. p. 9).
  • Technical Importance: The claimed invention provides a targeted therapy with a specific dosing schedule intended to offer a more effective and less toxic alternative to conventional chemotherapies for certain B-cell cancers (’083 Patent, col. 1:46-50).

Key Claims at a Glance

  • The complaint asserts independent claim 1 and dependent claim 8 (Compl. ¶¶ 32, 35).
  • The essential elements of independent claim 1 are:
    • A method of treating chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL) in a human subject suffering therefrom
    • comprising the step of orally administering, to the human subject, a dose of 100 mg twice daily of a Bruton's tyrosine kinase (BTK) inhibitor
    • wherein the BTK inhibitor is a compound of Formula (II) or a pharmaceutically acceptable salt, solvate, or hydrate thereof.

U.S. Patent No. 11,059,829 - "Crystal Forms of (S)-4-(8-amino-3-(1-but-2-ynoylpyrrolidin-2-yl)imidazo[1,5-a]pyrazin-1-yl)-N-(pyridin-2-yl)benzamide Maleate," issued July 13, 2021

The Invention Explained

  • Problem Addressed: Pharmaceutical development requires active ingredients to be in a stable, reproducible solid form to ensure consistent manufacturing, bioavailability, and shelf-life. The existence of multiple crystalline forms (polymorphs) for a single compound necessitates the identification of forms with optimal physical properties (’829 Patent, col. 1:18-24).
  • The Patented Solution: The invention identifies and characterizes specific crystalline forms of acalabrutinib maleate. The patent uses analytical techniques, primarily X-ray powder diffraction (XRPD), to define these forms by their unique structural fingerprints, as illustrated for one form in Figure 1 of the patent (’829 Patent, Abstract; Fig. 1).
  • Technical Importance: This technology provides a specific, well-defined solid form of the drug substance, which is a critical element for creating a consistent and effective pharmaceutical tablet product (’829 Patent, Abstract).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶¶ 50, 53).
  • The essential elements of independent claim 1 are:
    • A crystalline form of (S)-4-(8-amino-3-(1-but-2-ynoylpyrrolidin-2-yl)imidazo[1,5-a]pyrazin-1-yl)-N-(pyridin-2-yl)benzamide maleate,
    • characterized by a reflection X-ray powder diffraction pattern comprising peaks at 6.4, 8.6, 10.5, 11.6, and 15.7° 2θ±0.2° 2θ.

III. The Accused Instrumentality

Product Identification

MSN's Tablet ANDA Product, identified as a generic version of CALQUENCE® (acalabrutinib maleate) 100 mg base equivalent oral tablets (Compl. ¶¶ 1, 27).

Functionality and Market Context

The accused product is a tablet for oral administration containing the active ingredient acalabrutinib maleate (Compl. ¶27). Its intended use, as alleged by Plaintiffs, is for the treatment of adult patients with mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL), or small lymphocytic lymphoma (SLL) (Compl. ¶23). The complaint asserts that MSN seeks to commercially manufacture and sell this generic product in the United States upon receiving FDA approval (Compl. ¶¶ 1, 10). The chemical structure of the active ingredient, acalabrutinib, is depicted in the complaint (Compl. p. 9).

IV. Analysis of Infringement Allegations

10,272,083 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating chronic lymphocytic leukemia (CLL), small lymphocytic leukemia (SLL), or mantle cell lymphoma (MCL) in a human subject suffering therefrom... MSN's product is a generic version of CALQUENCE®, which is indicated for treating CLL and SLL, and MSN's proposed labeling allegedly directs such use. ¶23, ¶38 col. 27:60-63
...comprising the step of orally administering, to the human subject, a dose of 100 mg twice daily of a Bruton's tyrosine kinase (BTK) inhibitor... MSN's ANDA is for a 100 mg oral tablet, and its proposed labeling will allegedly direct patients and physicians to administer it on a twice-daily schedule. ¶27, ¶38 col. 28:1-4
...wherein the BTK inhibitor is a compound of Formula (II) or a pharmaceutically acceptable salt, hydrate, or solvate thereof. The active ingredient in MSN's product is acalabrutinib maleate, which is a maleate salt of the compound of Formula (II). ¶27 col. 28:5-10

Identified Points of Contention

  • Scope Questions: The primary question for infringement will be inducement. The analysis will focus on whether MSN's proposed product label, once finalized and approved, will inevitably instruct healthcare providers and patients to perform the steps of the claimed method, namely, administering a 100 mg dose twice daily for treating CLL or SLL. The complaint alleges that MSN's notice letter did not contest infringement on grounds other than invalidity, which may suggest this point is not in dispute (Compl. ¶35).

11,059,829 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A crystalline form of (S)-4-(8-amino-3-(1-but-2-ynoylpyrrolidin-2-yl)imidazo[1,5-a]pyrazin-1-yl)-N-(pyridin-2-yl)benzamide maleate... MSN's accused product is an oral tablet containing acalabrutinib maleate. ¶27 col. 127:65-67
...characterized by a reflection X-ray powder diffraction pattern comprising peaks at 6.4, 8.6, 10.5, 11.6, and 15.7° 2θ±0.2° 2θ. The complaint alleges on information and belief that the acalabrutinib maleate in MSN's product is a crystalline form that exhibits this specific X-ray powder diffraction pattern. ¶50, ¶54 col. 128:17-20

Identified Points of Contention

  • Technical Questions: The central factual question is whether the active pharmaceutical ingredient in MSN's ANDA product is, in fact, the specific crystalline form claimed in the ’829 Patent. This will turn on empirical evidence from analytical testing of MSN's product, such as XRPD analysis, to determine if it exhibits the characteristic peaks recited in the claim. As with the '083 patent, the complaint alleges MSN's challenge is limited to invalidity, suggesting the physical form of the drug may not be a point of contention (Compl. ¶53).

V. Key Claim Terms for Construction

  • The Term: "characterized by" (’829 Patent, Claim 1)
  • Context and Importance: This term precedes the list of XRPD peaks defining the claimed crystal form. Its construction is critical because it dictates whether the claim covers any crystal form having at least those peaks (an "open" list) or only a form defined exclusively by that pattern (a "closed" list). Practitioners may focus on this term because a defendant could attempt to avoid infringement by arguing its product has the recited peaks but also includes additional, distinct peaks, suggesting it is a different, unclaimed crystalline form.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The body of claim 1 recites "a crystal form... characterized by an X-ray powder diffraction pattern comprising certain peaks," and the subsequent dependent claims add further peaks to this list (’829 Patent, col. 128:17-30). The use of "comprising" and the addition of limitations in dependent claims may support an interpretation that the list in claim 1 is not exhaustive.
    • Evidence for a Narrower Interpretation: The specification discloses specific figures depicting the XRPD pattern of the invention (e.g., ’829 Patent, Fig. 1). A party might argue that "characterized by" requires substantial identity to the disclosed patterns, not merely the presence of a handful of selected peaks.

VI. Other Allegations

Indirect Infringement

The complaint alleges both induced and contributory infringement for both patents. Inducement is based on the allegation that MSN's proposed product labeling will instruct and encourage physicians and patients to use the accused product in an infringing manner (Compl. ¶¶ 38-39, 56-57). Contributory infringement is based on the allegation that MSN's product is especially made or adapted for an infringing use and is not suitable for substantial non-infringing use (Compl. ¶¶ 40, 58).

Willful Infringement

The complaint alleges that MSN has acted with "full knowledge" of the patents-in-suit, citing the Paragraph IV notice letter as evidence of this knowledge (Compl. ¶¶ 42, 60). While the term "willful" is not used, these allegations, coupled with the request for a finding of an exceptional case and attorneys' fees, form the basis for such a claim (Compl. Prayer for Relief ¶ g).

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

  • A central issue will be patent validity: The complaint asserts that MSN's Paragraph IV notice letter challenged the patents-in-suit only on grounds of invalidity, not non-infringement. Consequently, the case will likely focus on whether MSN can meet its burden of proving by clear and convincing evidence that the asserted claims are invalid, for example, on grounds of obviousness or lack of written description.
  • A key evidentiary question for the ’829 patent will be one of physical identity: Assuming infringement is contested, discovery will center on whether the crystalline form of acalabrutinib maleate in MSN’s ANDA product physically embodies the claimed invention, as determined by whether it exhibits the X-ray powder diffraction peaks required by the claim.
  • A core question for the ’083 patent will concern inducement via labeling: If infringement is contested, the analysis will turn on whether the language of MSN’s proposed—and ultimately FDA-approved—product label is sufficient to establish that MSN actively encouraged and intended for physicians and patients to perform the patented method of treatment.