DCT

1:24-cv-00396

Azurity Pharma Inc v. Hetero Labs Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:24-cv-00396, D. Del., 03/28/2024
  • Venue Allegations: Venue is alleged to be proper as to Defendant Hetero USA Inc. because it is a Delaware corporation and has previously consented to venue in the district. For the foreign-based Hetero entities, venue is alleged to be proper because they are alien defendants who may be sued in any judicial district.
  • Core Dispute: Plaintiffs allege that Defendants’ submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of the hypertension drug EDARBI® constitutes an act of infringement of a patent covering a stabilized pharmaceutical formulation.
  • Technical Context: The technology relates to pharmaceutical compositions designed to overcome the challenge of formulating a drug compound that is chemically unstable at a neutral pH but has low solubility at the acidic pH ranges where it is stable.
  • Key Procedural History: This is a Hatch-Waxman action filed in response to Defendants’ submission of ANDA No. 219062, which included a Paragraph IV certification asserting that the patent-in-suit is invalid, unenforceable, or will not be infringed. The patent-in-suit is listed in the FDA's "Orange Book" as covering the branded drug EDARBI®. The complaint was filed within the 45-day statutory window following receipt of Defendants' notice letter, triggering a potential 30-month stay of FDA approval for the generic product.

Case Timeline

Date Event
2007-03-28 '936 Patent Priority Date
2015-06-30 '936 Patent Issue Date
2024-02-16 Plaintiffs received Defendants' ANDA Notice Letter
2024-03-28 Complaint Filing Date

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

U.S. Patent No. 9,066,936 - "Solid pharmaceutical composition comprising a benzimidazole-7-carboxylate derivative and a pH control agent"

  • Issued: June 30, 2015

The Invention Explained

  • Problem Addressed: The patent addresses a formulation challenge with a specific drug, referred to as "compound (I)" (azilsartan medoxomil), which is a "promising therapeutic drug for hypertension" (’936 Patent, col. 2:3-6). This compound is unstable in the neutral pH range typically used for pharmaceutical preparations, but it has low solubility in the acidic pH range where it is stable, making it "extremely difficult to simultaneously afford the stability and solubility" of the compound (’936 Patent, col. 2:7-15).
  • The Patented Solution: The invention is a solid pharmaceutical composition that combines the active drug with a "pH control agent." The inventors discovered that by adding a pH control agent to the solid preparation to maintain a specific acidic pH range, they could create a formulation that was both stable during storage and exhibited good dissolution properties when administered (’936 Patent, col. 2:26-34). This approach resolved the conflicting requirements of stability and solubility.
  • Technical Importance: This technology provided a method to create a viable, stable, and effective oral solid dosage form for an important angiotensin II receptor antagonist. (’936 Patent, col. 1:55-58).

Key Claims at a Glance

  • The complaint asserts infringement of "one or more claims" of the ’936 patent (Compl. p. 10, ¶A). Independent claim 1 is central to the product composition.
  • Independent Claim 1:
    • A solid pharmaceutical composition comprising:
    • (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl 2-ethoxy-1-{[2'-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl) biphenyl-4-yl]methyl}-1H-benzimidazole-7-carboxylate potassium salt (the active ingredient, "Compound A"); and
    • a solid pH control agent which provides a pH of 3 to 5 when dissolved or suspended in water at a concentration of 1% w/v at 25° C.

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are "Hetero's Proposed ANDA Products," which are generic oral tablets containing 40 mg or 80 mg of azilsartan medoxomil, for which Defendants submitted ANDA No. 219062 to the FDA (Compl. ¶31).

Functionality and Market Context

The proposed products are intended to be generic equivalents of Plaintiffs’ branded drug EDARBI®, which is used to treat hypertension (Compl. ¶¶29, 32). The complaint alleges that the proposed generic products have the same active ingredient as EDARBI® and a "substantially the same proposed labeling" (Compl. ¶32). The filing of the ANDA signifies Defendants' intent to commercially manufacture, market, and sell these products in the United States upon receiving FDA approval (Compl. ¶31).

IV. Analysis of Infringement Allegations

The complaint alleges that Defendants' act of filing ANDA No. 219062 constitutes infringement under 35 U.S.C. § 271(e)(2)(A), and that the future commercial product would infringe one or more claims of the ’936 patent (Compl. ¶¶40-41). The complaint does not contain specific factual allegations detailing how the accused product meets each claim limitation, as Plaintiffs note they have not yet been provided with a copy of the ANDA itself (Compl. ¶36). No probative visual evidence provided in complaint.

The infringement theory is predicated on the allegation that the proposed generic is an equivalent to the branded EDARBI® product, which is covered by the ’936 patent.

’936 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A solid pharmaceutical composition comprising a compound which is (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl 2-ethoxy-1-{[2'-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl) biphenyl-4-yl]methyl}-1H-benzimidazole-7-carboxylate potassium salt The complaint alleges that Hetero's Proposed ANDA Products contain the same active ingredient as EDARBI®, which is the claimed compound. ¶32 col. 4:54-60
and a solid pH control agent which provides a pH of 3 to 5 when dissolved or suspended in water at a concentration of 1% w/v at 25° C. The complaint alleges on information and belief that the commercial manufacture and sale of Hetero's Proposed ANDA Products would infringe the ’936 patent, suggesting the product contains a component that meets this functional requirement. ¶41 col. 5:1-4; col. 22:1-2

Identified Points of Contention

  • Scope Questions: A central question may be the scope of the term "solid pH control agent." The dispute could involve whether an excipient included in the formulation for another primary purpose (e.g., as a binder or disintegrant) that also happens to provide the claimed pH function falls within the scope of this term.
  • Technical Questions: The primary technical question, to be resolved through discovery of the ANDA, is what excipients are used in Hetero's formulation. Does any single excipient or combination of excipients in the accused product function as a "solid pH control agent" that "provides a pH of 3 to 5" under the specific test conditions recited in the claim? The complaint offers no direct evidence on this point.

V. Key Claim Terms for Construction

"solid pH control agent which provides a pH of 3 to 5 when dissolved or suspended in water at a concentration of 1% w/v at 25° C."

Context and Importance

This functional limitation is the core of the asserted invention, distinguishing it from the prior art. The outcome of the infringement analysis will likely depend on the construction of this term and whether any component in the accused product meets this definition.

Intrinsic Evidence for Interpretation

  • Evidence for a Broader Interpretation: Plaintiffs may argue that the claim language is purely functional and covers any solid substance that achieves the specified pH result, regardless of its name or primary purpose. The specification provides a non-exhaustive list of potential agents, including various acids and combinations, suggesting the term is not limited to a specific class of compounds (’936 Patent, col. 5:5-13, 40-42).
  • Evidence for a Narrower Interpretation: Defendants may argue that the term implies an ingredient added specifically for the purpose of controlling pH. The specification repeatedly describes a method that "comprises adding a pH control agent" to the composition, suggesting a deliberate act of inclusion for that function (’936 Patent, col. 3:1-4). The numerous examples in the patent all involve the explicit addition of a named pH control agent, such as monosodium fumarate or a combination of fumaric acid and sodium hydroxide (’936 Patent, Examples 1-18).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement and contributory infringement "on information and belief," based on the future use of the accused product "in accordance with its proposed labeling" (Compl. ¶41).
  • Willful Infringement: Willfulness is alleged based on Defendants' awareness of the ’936 patent, which the complaint asserts is demonstrated by the act of filing an ANDA with a Paragraph IV certification against that patent (Compl. ¶44). This alleges pre-suit knowledge of the patent and the alleged infringement.

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

  • A core issue will be one of definitional scope: can the functional term "solid pH control agent," which is defined by a specific pH test, be construed to read on a pharmaceutical excipient that may have a different primary function (e.g., binder, filler) but incidentally satisfies the claimed pH requirement?
  • A key evidentiary question will be one of compositional fact: what is the precise formulation of Hetero's proposed generic product as detailed in its ANDA? Will discovery reveal a component or combination of components that performs the function of the "pH control agent" as claimed, thereby resolving the central factual dispute over infringement?