PH Health Ltd v. Fresenius Kabi USA LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: PH Health Limited (Ireland)
  • Defendant: Fresenius Kabi USA, LLC (Delaware / Illinois)
  • Plaintiff’s Counsel: Axinn, Veltrop & Harkrider LLP
• Case Identification: 1:25-cv-01096, D. Del., 08/29/2025
• Venue Allegations: Venue is alleged to be proper in the District of Delaware because the Defendant is a Delaware corporation.
• Core Dispute: Plaintiff alleges that Defendant’s submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic ephedrine sulfate injection constitutes an act of infringement of a patent directed to a storage-stable, ready-to-use formulation of the drug.
• Technical Context: The technology concerns pharmaceutical formulations for injectable drugs, specifically addressing the challenges of maintaining pH stability in diluted, ready-to-administer solutions to improve safety and efficiency in clinical settings.
• Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendant’s submission of an ANDA with a Paragraph IV certification, asserting that Plaintiff’s patent is invalid, unenforceable, or will not be infringed by Defendant’s proposed generic product. The complaint was filed within the 45-day statutory window after Plaintiff received Defendant's notice letter, triggering a potential 30-month stay of FDA approval for the generic product.

Case Timeline

Date	Event
2020-01-22	’845 Patent Priority Date
2020-10-16	Plaintiff's New Drug Application (NDA) Approved
2020-12-22	’845 Patent Issued
2022-03-01	Plaintiff's Commercial Marketing Began
2025-07-17	Defendant's Paragraph IV Notice Letter Sent
2025-08-29	Complaint Filed

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

U.S. Patent No. 10,869,845 - “Ephedrine Compositions and Methods”

The Invention Explained

• Problem Addressed: Commercially available ephedrine sulfate injections were highly concentrated and required dilution by medical personnel before administration. This dilution process was time-consuming, created risks of contamination and dosage errors, and resulted in a solution that was not pH stable and therefore not recommended for storage (’845 Patent, col. 2:46-64; Compl. ¶14).
• The Patented Solution: The patent describes a premixed, "ready-to-use" ephedrine solution that is chemically stable for long-term storage. The solution achieves this stability through a specific formulation that includes ephedrine sulfate, sodium chloride, water, and, critically, acetic acid as a pH adjuster to maintain the initial pH within a narrow range of 4.6 to 4.8 (’845 Patent, Abstract; col. 6:1-17). This formulation is designed to exhibit minimal pH drift and impurity formation over time, even after six months of storage (’845 Patent, col. 6:4-10).
• Technical Importance: This innovation provides clinicians with a sterile, pre-diluted ephedrine product, which can enhance patient safety by eliminating potential dilution errors and save critical time in settings like anesthesia where hypotension must be treated promptly (Compl. ¶15).

Key Claims at a Glance

• The complaint asserts infringement of at least Claim 1 of the ’845 Patent (Compl. ¶29).
• The essential elements of independent Claim 1 are:
  • A storage-stable, sterile ephedrine ready-to-use solution composition, comprising:
  • about 5 mg/mL of ephedrine or a pharmaceutically acceptable salt thereof;
  • about 9 mg/mL of sodium chloride;
  • a pH adjuster comprising acetic acid; and
  • water,
  • wherein the initial adjusted pH of the composition is in the range of 4.6 to 4.8;
  • wherein the pH drift of the composition is less than 0.5 after storage for 6 months at 25° C. and 60% relative humidity; and
  • wherein the composition contains about 5% or less total impurities after storage for 6 months at 25° C. and 60% relative humidity as determined by HPLC.
• The complaint does not explicitly reserve the right to assert dependent claims, but alleges infringement of "one or more claims" (Compl. ¶25).

III. The Accused Instrumentality

Product Identification

• Defendant’s proposed ephedrine sulfate injection, 50 mg/10mL single-dose vial, which is the subject of Abbreviated New Drug Application (“ANDA”) No. 219991 (Compl. ¶16).

Functionality and Market Context

• The accused product is a proposed generic version of Plaintiff’s Ephedrine SD Vials (Compl. ¶20). As an ANDA product, it is intended to have the same active ingredient, concentration, and administration route as Plaintiff's approved drug product (Compl. ¶¶ 19, 32). The complaint alleges that the formulation of Defendant's proposed product contains the same key components and exhibits the same stability characteristics as those recited in the asserted claims of the ’845 Patent (Compl. ¶¶ 33-34). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

’845 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A storage-stable, sterile ephedrine ready-to-use solution composition...	Defendant’s Proposed ANDA Product is alleged to be a storage-stable, sterile, ready-to-use ephedrine solution.	¶33, ¶34	col. 6:1-2
...comprising: about 5 mg/mL of ephedrine or a pharmaceutically acceptable salt thereof;	The Proposed ANDA Product contains ephedrine sulfate at a concentration of 50 mg/10 mL (or 5 mg/mL).	¶19, ¶33	col. 6:1-2
about 9 mg/mL of sodium chloride;	The Proposed ANDA Product comprises sodium chloride.	¶33	col. 6:2-3
a pH adjuster comprising acetic acid; and water,	The Proposed ANDA Product comprises a pH adjuster with acetic acid and water.	¶33	col. 6:3-4
wherein the initial adjusted pH of the composition is in the range of 4.6 to 4.8;	The Proposed ANDA Product is alleged to have an initial adjusted pH in the claimed range.	¶34	col. 6:4-6
wherein the pH drift of the composition is less than 0.5 after storage for 6 months...; and	The Proposed ANDA Product is alleged to have a pH drift within the claimed range after storage.	¶34	col. 6:6-8
wherein the composition contains about 5% or less total impurities after storage for 6 months...	The Proposed ANDA Product is alleged to have total impurities within the claimed range after storage.	¶34	col. 6:8-12

Identified Points of Contention

• Evidentiary Questions: The central dispute will likely concern the characteristics of a product not yet on the market. The complaint alleges on "information and belief" that Defendant's product meets the quantitative stability limitations (pH drift and impurity levels) (Compl. ¶34). The key question for the court will be whether the confidential data and product specifications contained within Defendant’s ANDA submission to the FDA demonstrate that the proposed product will, in fact, meet these limitations.
• Scope Questions: The interpretation of the term "about" (e.g., "about 5 mg/mL") may become a point of contention. The analysis will raise the question of what degree of numerical variation is permissible while remaining within the scope of the claims, particularly if Defendant's ANDA specifies a concentration slightly different from 5 mg/mL.

V. Key Claim Terms for Construction

The Term: "storage-stable"

• Context and Importance: This term appears in the preamble of Claim 1 and is central to the invention's purpose. The infringement analysis depends on whether Defendant's formulation can be characterized as "storage-stable." Practitioners may focus on whether this term is defined exclusively by the three specific "wherein" clauses that follow it (initial pH, pH drift, and impurity limits), or if it imparts a broader, separate limitation.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification discusses stability over longer periods, such as "up to 24 months," which a party could argue informs the general meaning of the term beyond the specific 6-month metrics in Claim 1 (’845 Patent, col. 8:6-10).
  • Evidence for a Narrower Interpretation: A party could argue that the claim itself acts as its own lexicon, defining "storage-stable" by the three specific, objective, and quantitative limitations that follow in the body of the claim. Under this view, if the accused product meets those three metrics, it is "storage-stable" for the purposes of Claim 1, regardless of any broader definitions in the specification.

The Term: "about"

• Context and Importance: This term of degree is used to qualify the concentrations of both ephedrine ("about 5 mg/mL") and sodium chloride ("about 9 mg/mL"). Its scope is critical for determining literal infringement, as a generic formulation may seek to use a concentration that is therapeutically equivalent but numerically distinct.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification discloses various concentration ranges, such as "4 mg/mL to 6 mg/mL of ephredine," suggesting that the inventors contemplated some flexibility around the 5 mg/mL value (’845 Patent, col. 2:22-23).
  • Evidence for a Narrower Interpretation: The specific recital of "about 5 mg/mL" in the claim, as opposed to a broader range, could be argued to connote a value very close to 5.0, with only minor variations for manufacturing tolerances. Example formulations in the patent also specify exact concentrations, which may be used to argue for a narrower construction (’845 Patent, Table 1).

VI. Other Allegations

• Indirect Infringement: The complaint alleges that upon FDA approval, Defendant will actively induce infringement by selling its product with instructions for its use, thereby causing healthcare providers to directly infringe (Compl. ¶27). Knowledge is alleged based on Defendant’s submission of the Paragraph IV certification, which acknowledges the existence of the ’845 Patent (Compl. ¶18, ¶28).
• Willful Infringement: Willfulness is alleged based on Defendant’s pre-suit knowledge of the ’845 Patent, evidenced by its Paragraph IV certification and notice letter (Compl. ¶17-18). The complaint seeks increased damages for what it characterizes as willful and deliberate infringement (Compl. p. 8, ¶F).

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

• A primary issue will be one of evidentiary proof: does the technical data within Defendant's confidential ANDA filing—specifically its stability studies and product specifications—demonstrate on its face that the proposed generic product will meet the precise quantitative limitations for pH drift and impurity levels as required by Claim 1?
• The case may also turn on a question of definitional scope: how much deviation from the recited values does the term "about" permit? This will determine whether a formulation with a concentration numerically different from "5 mg/mL" can avoid literal infringement while being bioequivalent.
• Finally, a key strategic question inherent in this ANDA litigation is whether Defendant’s non-infringement and/or invalidity positions, as articulated in its Paragraph IV certification, are substantial enough to overcome the infringement allegations, which are based on the premise that the generic product is designed to be a copy of the patented original.