DCT

1:25-cv-00861

PH Health Ltd v. Baxter Healthcare Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00861, D. Del., 09/19/2025
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant is a Delaware corporation and is subject to personal jurisdiction in the district.
  • Core Dispute: Plaintiffs allege that Defendant’s proposed generic epinephrine injection product, for which it has sought FDA approval, will infringe five patents related to stable, ready-to-use epinephrine compositions.
  • Technical Context: The technology concerns pharmaceutical formulations designed to solve the long-standing problem of epinephrine’s instability in aqueous solutions, enabling the creation of premixed, ready-to-administer IV bags for treating conditions like septic shock.
  • Key Procedural History: This action arises under the Hatch-Waxman Act, triggered by Defendant’s submission of a supplemental New Drug Application (sNDA) to the FDA. The sNDA contained a Paragraph IV Certification asserting that Plaintiffs' patents are invalid, unenforceable, and/or will not be infringed by Defendant's proposed product.

Case Timeline

Date Event
2012-12-07 FDA approval of Adrenalin® single-dose vials
2012-12-18 FDA approval of Adrenalin® multi-dose vials
2018-03-23 Earliest Priority Date for all Patents-in-Suit
2020-05-19 U.S. Patent No. 10,653,646 Issued
2021-07-27 U.S. Patent No. 11,071,719 Issued
2021-08-10 U.S. Patent No. 11,083,698 Issued
2021-12-28 U.S. Patent No. 11,207,280 Issued
2023-05-10 ’646, ’280, and ’698 Patents listed in FDA Orange Book
2024-11-05 U.S. Patent No. 12,133,837 Issued
2024-11-06 ’837 Patent listed in FDA Orange Book
2025-05-29 Defendant sends Paragraph IV Notice Letter to Plaintiffs
2025-09-19 Complaint Filed

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

U.S. Patent No. 11,071,719 - Epinephrine Compositions and Containers

The Invention Explained

  • Problem Addressed: The patent background describes the chemical instability of epinephrine in aqueous solutions, which deteriorates rapidly upon exposure to air or light, especially at low concentrations suitable for direct administration (Compl. ¶¶ 32-33). This instability historically required epinephrine to be sold in concentrated forms that necessitate dilution in a clinical setting, creating risks of dilution errors, microbial contamination, and limited shelf-life after preparation (’719 Patent, col. 3:36-49).
  • The Patented Solution: The invention is a method for producing a stable, ready-to-inject, low-concentration epinephrine composition that is "substantially antioxidant-free" (’719 Patent, col. 7:60-64). Stability is achieved by combining several key steps: controlling the dissolved oxygen in the aqueous carrier to below 2 ppm, adjusting the pH to a mildly acidic range of 3.0-4.7, and including a specific concentration of a metal ion chelator (e.g., EDTA) to slow autoxidation (’719 Patent, col. 4:1-17). The final product is then packaged in a container under an inert gas and terminally sterilized.
  • Technical Importance: This technical approach enabled the development of the first FDA-approved, manufacturer-prepared, premixed epinephrine intravenous (IV) bag, enhancing patient safety by eliminating the need for bedside dilution (Compl. ¶36).

Key Claims at a Glance

The complaint does not specify which claims are asserted, alleging infringement of "one or more claims" (Compl. ¶46). Independent claim 1 is representative of the patented method.

  • Independent Claim 1: A method of producing a storage stable ready-to-inject epinephrine composition, comprising the steps of:
    • Combining an aqueous pharmaceutically acceptable carrier with epinephrine to a concentration of ≤ 0.07 mg/mL, where substantially all epinephrine is the R-isomer, and the carrier has ≤ 2 ppm of dissolved oxygen.
    • Adjusting the pH of the composition to between 3.0-4.7.
    • Including a metal ion chelator (selected from EDTA, EGTA, and diethylenetriaminepentaacetic acid) at a concentration of 1-50 mcg/mL.
    • Packaging the composition into a container under an inert gas.
    • Sterilizing the composition, where the resulting product is substantially antioxidant-free and maintains specified low levels of total impurities and S-isomer content after one month of storage.
  • The complaint reserves the right to assert other claims, which may include dependent claims (Compl. ¶46).

U.S. Patent No. 11,207,280 - Epinephrine Compositions and Containers

The Invention Explained

  • Problem Addressed: Similar to the ’719 Patent, this patent addresses the problem of epinephrine degradation in diluted, ready-to-use aqueous solutions, which lose potency through oxidation and racemization, and the risks associated with prior art stabilization techniques that used potentially allergenic antioxidants (’280 Patent, col. 3:3-15).
  • The Patented Solution: The patent claims the composition itself: a sterile, storage-stable, and ready-to-inject epinephrine formulation. The solution is characterized by being substantially antioxidant-free and containing three key stabilizing features: a low concentration of epinephrine (≤ 0.07 mg/ml), a strictly controlled acidic pH (3.5-4.7), and the presence of a metal ion chelator (’280 Patent, Abstract; Claim 1). This combination allows the product to remain stable, with low impurity and S-isomer levels, after autoclaving and extended storage.
  • Technical Importance: The claimed composition provides a solution that is stable enough to be manufactured, packaged, and stored in a ready-to-administer format, thereby improving safety and convenience in clinical settings for treating hypotension (Compl. ¶¶ 29, 34).

Key Claims at a Glance

The complaint alleges infringement of "one or more claims" (Compl. ¶54). Independent claim 1 is representative of the patented composition.

  • Independent Claim 1: A sterile storage stable ready-to-inject epinephrine composition, comprising:
    • An aqueous carrier containing epinephrine (at ≤ 0.07 mg/ml, with at least 90 mol % as the R-isomer) and a metal ion chelator.
    • The composition has a pH between 3.5-4.7.
    • The composition is substantially antioxidant-free.
    • After storage for at least one month at 25° C., the composition has total impurities of equal or less than 0.7% and S-isomer content of less than 4%.
  • The complaint reserves the right to assert other claims (Compl. ¶54).

U.S. Patent No. 12,133,837 - Epinephrine Compositions and Containers

  • Technology Synopsis: This patent is part of the same family as the patents analyzed above and is directed to similar technology. It claims a sterile, ready-to-inject epinephrine composition stabilized without traditional antioxidants through the use of a controlled pH, a metal ion chelator, and a tonicity agent, maintaining low impurity levels after storage (’837 Patent, Abstract).
  • Asserted Claims: The complaint asserts infringement of one or more claims (Compl. ¶62).
  • Accused Features: The accused features are the composition and characteristics of Defendant's Proposed sNDA Product (Compl. ¶62).

U.S. Patent No. 10,653,646 - Epinephrine Compositions and Containers

  • Technology Synopsis: As a parent to the other asserted patents, this patent discloses and claims an antioxidant-free, ready-to-inject epinephrine composition with improved stability. The invention achieves stability by combining epinephrine in an aqueous carrier with a metal ion chelator at a specific pH range (3.0-4.7), resulting in a formulation with low impurity and S-isomer content after storage (’646 Patent, Abstract, Claim 1).
  • Asserted Claims: The complaint asserts infringement of one or more claims (Compl. ¶70).
  • Accused Features: The accused features are the composition and characteristics of Defendant's Proposed sNDA Product (Compl. ¶70).

U.S. Patent No. 11,083,698 - Epinephrine Compositions and Containers

  • Technology Synopsis: This patent, also in the same family, is directed to methods of administering the stable, antioxidant-free epinephrine composition. It claims a method of increasing blood pressure in a patient by providing and administering the claimed sterile epinephrine solution, which is characterized by its specific pH range, concentration, and the presence of a metal ion chelator (’698 Patent, Abstract, Claim 1).
  • Asserted Claims: The complaint asserts infringement of one or more claims (Compl. ¶78).
  • Accused Features: The accused features are the composition and intended use of Defendant's Proposed sNDA Product as will be described in its labeling (Compl. ¶¶ 78, 80).

III. The Accused Instrumentality

Product Identification

  • Defendant’s "Epinephrine in 0.9% Sodium Chloride Injection, 4 mg/250 mL (16 mcg/mL)," referred to as the "Proposed sNDA Product" (Compl. ¶1).

Functionality and Market Context

  • The Proposed sNDA Product is a pharmaceutical formulation for which Defendant seeks FDA approval to market as a generic alternative to Plaintiffs' Adrenalin® product (Compl. ¶¶ 1, 40). The complaint alleges, on information and belief, that the product contains epinephrine at the specified concentration and that its proposed product label will instruct healthcare providers to use it to increase mean arterial blood pressure in adult patients with hypotension associated with septic shock (Compl. ¶¶ 39, 41). The complaint also alleges that Defendant's sNDA relies on data demonstrating the bioequivalence of its proposed product to Plaintiffs' approved Adrenalin® product (Compl. ¶40).

IV. Analysis of Infringement Allegations

The complaint does not provide a claim chart or a detailed, element-by-element infringement analysis. It states that Defendant’s Paragraph IV Notice Letter provided only "conclusory arguments of non-infringement" and that Plaintiffs require discovery to confirm their belief of infringement (Compl. ¶¶ 45, 53). The general infringement theory is that Defendant's submission of an sNDA for a product that is bioequivalent to Plaintiffs' Adrenalin® product constitutes an act of infringement under 35 U.S.C. § 271(e)(2), and that the future manufacture, use, or sale of the product will constitute direct and indirect infringement (Compl. ¶¶ 47, 55). The core allegation is that the Proposed sNDA Product, by its nature and intended use, will necessarily possess the chemical composition and meet the stability characteristics required by the claims of the Patents-in-Suit (Compl. ¶39).

No probative visual evidence provided in complaint.

Identified Points of Contention

  • Factual Scope: A primary factual question will be whether the precise formulation of Defendant's Proposed sNDA Product—including its pH, concentration and type of metal ion chelator, S-isomer content, and total impurity levels after manufacturing and storage—falls within the specific quantitative ranges recited in the asserted claims.
  • Method Claim Infringement: For method claims, such as those in the ’719 Patent, a point of contention may be how the act of filing an sNDA under § 271(e)(2) constitutes infringement of claims directed to a "method of producing" a composition. This is a well-established legal pathway, but the specific facts supporting it will be subject to discovery and argument.
  • Validity and Enforceability: Defendant’s Paragraph IV certification inherently raises the question of whether the asserted claims are invalid as obvious or anticipated by prior art, or are otherwise unenforceable (Compl. ¶37).

V. Key Claim Terms for Construction

The Term: "substantially antioxidant-free"

  • Context and Importance: This term is central to the invention's purported novelty, which is achieving stability without the use of traditional antioxidants known to cause allergic reactions. The scope of this negative limitation is critical, as any amount of antioxidant in Defendant's product could be relevant to the infringement analysis. Practitioners may focus on this term because it defines the core departure from prior art stabilization techniques.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claims themselves do not set a numerical limit, suggesting the term could be interpreted functionally as lacking an effective amount of an antioxidant to reduce degradation.
    • Evidence for a Narrower Interpretation: The specification provides a precise, quantitative definition, stating the composition "will include antioxidants in an amount of equal or less than about 0.01 wt %, or equal or less than about 0.001 wt %, or equal or less than about 0.0001 wt %" (’719 Patent, col. 7:64-col. 8:4). A defendant would likely argue this language strictly defines the upper boundary for what is "substantially antioxidant-free."

The Term: "metal ion chelator"

  • Context and Importance: This is the key active stabilizing agent in the claimed formulation. Its definition will determine what range of compounds in an accused product could satisfy this claim element.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The term itself is functional. A plaintiff may argue it should be construed to cover any compound that performs the function of chelating metal ions to slow epinephrine degradation, as described in the patent. The specification lists "various bicarboxylic acids, tricarboxylic acids, and aminopolycarboxylic acids" as examples, suggesting a potentially broad class (’719 Patent, col. 7:25-27).
    • Evidence for a Narrower Interpretation: Asserted independent claims in the ’719 and ’280 patents explicitly limit the term to a selection from "EDTA (edetic acid), EGTA, and diethylenetriaminepentaacetic acid." This express Markush group language may be argued to strictly limit the scope of the term in those specific claims, though other claims or patents in the family might use broader language.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement, stating that Defendant’s proposed product label will instruct healthcare providers to administer the product for its approved indication, thereby causing direct infringement by end-users (Compl. ¶¶ 41, 48-49, 56-57).
  • Willful Infringement: The complaint does not use the word "willful" but lays a foundation for such a claim. It alleges that Defendant had knowledge of the Patents-in-Suit when it submitted its sNDA with a Paragraph IV certification, and acted with specific intent to infringe (Compl. ¶¶ 38, 50, 58). Plaintiffs also request a declaration that the case is "exceptional" to recover attorneys' fees under 35 U.S.C. § 285 (Prayer for Relief ¶e).

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

  • A primary issue will be one of compositional overlap: once the full chemical and physical characteristics of Defendant's Proposed sNDA Product are revealed through discovery, will its formulation—specifically its pH, S-isomer content, impurity profile, and the identity and concentration of any chelating agents—fall squarely within the quantitative boundaries defined by the asserted claims?
  • The central legal battle will likely concern validity: can Plaintiffs defend the non-obviousness of a formulation that combines several individually known elements (epinephrine, an acidic pH, and a metal ion chelator) to solve the well-known problem of epinephrine instability, or will Defendant succeed in arguing that this combination was an obvious-to-try solution for a skilled formulator?
  • A key evidentiary question will be one of infringement under § 271(e)(2): what evidence will Plaintiffs present to demonstrate that the product Defendant will market, if its sNDA is approved, would infringe the asserted claims, particularly for method claims directed at the manufacturing process?