DCT

1:24-cv-00066

Eagle Pharma Inc v. Baxter Healthcare Corp

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Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:24-cv-00066, D. Del., 06/12/2025
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant is a Delaware corporation and therefore resides in the district for venue purposes.
  • Core Dispute: Plaintiff alleges that Defendant’s bendamustine hydrochloride injection product infringes two patents related to long-term storage stable liquid formulations of the chemotherapy drug.
  • Technical Context: The technology concerns pharmaceutical formulations designed to overcome the chemical instability of bendamustine, which traditionally required it to be supplied as a lyophilized powder that is inconvenient to reconstitute before administration.
  • Key Procedural History: The complaint notes prior litigation between Plaintiff and Celerity Pharmaceuticals, the original developer of the accused product, concerning a related patent. The complaint alleges that Defendant Baxter was involved in that litigation and has monitored Plaintiff's patent filings, suggesting a basis for pre-suit knowledge of the asserted patent family. Plaintiff also alleges it sent notice letters to Defendant upon issuance of each of the patents-in-suit.

Case Timeline

Date Event
2010-01-28 Earliest Priority Date for ’783 and ’214 Patents
2018-05-15 FDA Approval of BELRAPZO (Plaintiff's Product)
2022-12-15 FDA Approval of Baxter's Bendamustine Product
2023-12-19 U.S. Patent No. 11,844,783 Issues
2024-01-16 U.S. Patent No. 11,872,214 Issues
2025-06-12 Second Amended Complaint Filed

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

U.S. Patent No. 11,844,783 - *"Formulations of Bendamustine"*

The Invention Explained

  • Problem Addressed: The patent’s background explains that bendamustine is chemically unstable in aqueous solutions, degrading rapidly via hydrolysis. This instability necessitates supplying the drug as a lyophilized (freeze-dried) powder, which is clinically inconvenient and time-consuming to reconstitute prior to patient administration (Compl., Ex. A, ’783 Patent, col. 1:49-65).
  • The Patented Solution: The invention provides a liquid, ready-to-use or ready-to-dilute bendamustine formulation with enhanced long-term stability. The solution uses a non-aqueous, pharmaceutically acceptable fluid, such as polyethylene glycol (PEG) or propylene glycol (PG), combined with a stabilizing antioxidant to prevent degradation, thereby eliminating the need for reconstitution by clinicians (’783 Patent, col. 2:5-26, col. 3:1-7).
  • Technical Importance: This approach simplifies the clinical workflow for administering bendamustine, reducing preparation time and potential errors associated with reconstituting lyophilized powders (’783 Patent, col. 2:24-26).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶45).
  • Essential elements of claim 1 include:
    • A method of treating leukemia comprising providing a liquid bendamustine composition with a concentration of 20-60 mg/mL.
    • The composition contains a pharmaceutically acceptable fluid "consisting of" polyethylene glycol and optionally one or more of propylene glycol, ethanol, benzyl alcohol, and glycofurol.
    • The composition contains a "stabilizing amount of an antioxidant."
    • The composition has less than 5% total impurities after at least 15 months of storage at 5°C to 25°C.
    • The method includes the steps of diluting the composition and intravenously administering it.
  • The complaint reserves the right to assert additional claims (Compl. ¶45).

U.S. Patent No. 11,872,214 - *"Formulations of Bendamustine"*

The Invention Explained

  • Problem Addressed: As with the related ’783 Patent, the ’214 Patent addresses the problem of bendamustine’s rapid degradation in aqueous solutions, which necessitates its supply as an inconvenient lyophilized powder (Compl., Ex. B, ’214 Patent, col. 1:49-65).
  • The Patented Solution: The patent describes a stable liquid bendamustine formulation that avoids the need for reconstitution. The solution is achieved by using a non-aqueous fluid comprised of solvents like polyethylene glycol, combined with a stabilizing antioxidant to ensure long-term chemical stability (’214 Patent, col. 2:5-26, col. 3:1-7).
  • Technical Importance: The invention provides a "ready to use" formulation that enhances clinical convenience and safety by eliminating the reconstitution step for the chemotherapy drug (’214 Patent, col. 2:24-26).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶55).
  • Essential elements of claim 1 include:
    • A sterile vial containing a liquid bendamustine composition.
    • The composition contains about 100 mg of bendamustine at a concentration from about 25 mg/mL.
    • The composition contains a pharmaceutically acceptable fluid "consisting of" polyethylene glycol and optionally one or more of propylene glycol, ethanol, benzyl alcohol, and glycofurol.
    • The composition contains a "stabilizing amount of an antioxidant."
    • The composition has less than 5% total impurities after at least 15 months of storage at 5°C to 25°C.
  • The complaint reserves the right to assert additional claims (Compl. ¶55).

III. The Accused Instrumentality

  • Product Identification: Baxter Healthcare Corporation’s bendamustine hydrochloride injection product, approved under New Drug Application (NDA) No. 216078 (Compl. ¶1).
  • Functionality and Market Context: The accused product is a liquid, sterile solution of bendamustine hydrochloride intended for intravenous administration after dilution (Compl. ¶¶29-30). According to its approved label, the product is supplied in a 100 mg/4 mL multiple-dose vial, yielding a concentration of 25 mg/mL (Compl. ¶¶27-28). The formulation is alleged to contain polyethylene glycol, ethanol, and the antioxidant monothioglycerol (Compl. ¶¶31, 38). The complaint alleges the product is marketed for the treatment of chronic lymphocytic leukemia, among other indications (Compl. ¶43). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

U.S. Patent No. 11,844,783 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating leukemia... comprising providing a liquid bendamustine-containing composition... wherein the bendamustine concentration... is from about 20 mg/mL to about 60 mg/mL The accused product is a liquid solution with a bendamustine concentration of 25 mg/mL, and its label promotes administration to patients with chronic lymphocytic leukemia. ¶27, ¶29, ¶43 col. 3:20-24
a pharmaceutically acceptable fluid consisting of polyethylene glycol and optionally one or more of propylene glycol, ethanol, benzyl alcohol and glycofurol The accused product contains polyethylene glycol and ethanol as fluid components. ¶31 col. 3:35-52
a stabilizing amount of an antioxidant The accused product contains 5 mg/mL of monothioglycerol, which is identified as an antioxidant alleged to provide a stabilizing effect. ¶38 col. 4:1-26
wherein the total impurities... is less than about 5% peak area response... after at least about 15 months at a temperature of about 5° C to about 25° C Alleged on information and belief, based on the product’s FDA-approved 18-month shelf life and bioequivalence data. ¶39, ¶41 col. 3:8-14
diluting the liquid bendamustine containing composition; and intravenously administering the diluted composition to the human The product label instructs healthcare professionals to aseptically withdraw and dilute the required dose in an infusion bag for intravenous administration. ¶30, ¶46 col. 14:19-22

U.S. Patent No. 11,872,214 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A sterile vial containing a liquid bendamustine-containing composition comprising about 100 mg of bendamustine... wherein the bendamustine concentration... is from about 25 mg/mL The accused product is a liquid solution provided in a sterile 100 mg/4 mL vial, which corresponds to 100 mg of bendamustine at a concentration of 25 mg/mL. ¶27, ¶28, ¶56 col. 3:20-24
a pharmaceutically acceptable fluid consisting of polyethylene glycol and optionally one or more of propylene glycol, ethanol, benzyl alcohol and glycofurol The accused product contains polyethylene glycol and ethanol. ¶31, ¶56 col. 3:35-52
a stabilizing amount of an antioxidant The accused product contains 5 mg/mL of monothioglycerol, an antioxidant alleged to be a stabilizing amount. ¶38, ¶56 col. 4:1-26
wherein the total impurities... is less than about 5% peak area response... after at least about 15 months at a temperature of about 5° C to about 25° C Alleged on information and belief that the product's stability profile meets this limitation, based on its FDA approval. ¶39, ¶41 col. 3:8-14
  • Identified Points of Contention:
    • Scope Questions: The complaint anticipates a central dispute over the claim term "consisting of." The accused product's label notes that sodium hydroxide is used "to adjust the acidity of [the] polyethylene glycol 400" (Compl. ¶32). This raises the question of whether the presence or use of sodium hydroxide, an unlisted substance, means the accused fluid falls outside the scope of a fluid "consisting of" the specifically enumerated components. The complaint argues that sodium hydroxide is a non-component processing aid that is either not present in the final product or is consumed, and thus does not vitiate this limitation (Compl. ¶¶32-37).
    • Technical Questions: A primary evidentiary question will be whether the accused product actually meets the impurity limitation (<5% total impurities after 15 months at 5-25°C). The complaint alleges this on "information and belief," citing the product's 18-month approved shelf life as circumstantial evidence (Compl. ¶¶39, 41). The actual stability data for the accused product will be a key focus of discovery.

V. Key Claim Terms for Construction

  • The Term: "pharmaceutically acceptable fluid consisting of"
  • Context and Importance: This term appears in the asserted independent claim of both patents-in-suit. Its construction is critical because the accused product's label discloses the use of sodium hydroxide, which is not an ingredient listed in the "consisting of" clause. The infringement analysis may turn entirely on whether this term permits the presence of an unlisted pH-adjusting agent.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: Plaintiff may argue that the specification's focus is on the bulk solvents (PEG, PG, etc.) as the core of the non-aqueous fluid that provides stability, suggesting that minor, unlisted processing aids or pH adjusters that do not alter the fundamental character of the fluid are not excluded (’783 Patent, col. 3:57-65). The patent's objective is to solve the hydrolysis problem, which is achieved by replacing water with these non-aqueous solvents.
    • Evidence for a Narrower Interpretation: Defendant may argue that "consisting of" is a term of art in patent law that closes the claim to any elements not specified. The claims provide a specific list of optional ingredients (e.g., propylene glycol, ethanol), and sodium hydroxide is not on that list (’783 Patent, cl. 1; ’214 Patent, cl. 1). The absence of any mention of pH adjusters in the specification could support an interpretation that they were not contemplated as part of the claimed fluid.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement of infringement of the ’783 Patent. It asserts that Defendant's product label instructs and encourages healthcare professionals to perform the claimed method steps of diluting the liquid bendamustine composition and intravenously administering it to treat leukemia (Compl. ¶¶46-47).
  • Willful Infringement: Willfulness is alleged for both patents based on Defendant's alleged pre-suit knowledge. The complaint asserts Defendant was aware of Plaintiff's patent portfolio through its involvement in prior litigation concerning a related patent and by monitoring Plaintiff’s patent family. Furthermore, Plaintiff alleges it provided direct notice to Defendant via letters upon the issuance of the ’783 patent on December 20, 2023, and the ’214 patent on January 16, 2024 (Compl. ¶¶48, 58).

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

  • A core issue will be one of claim scope and construction: does the term "consisting of," as used to define the composition of the pharmaceutically acceptable fluid, strictly exclude any unlisted substance, or can it be interpreted to permit the presence of a processing aid like the sodium hydroxide used for pH adjustment in the accused product?
  • A key evidentiary question will be one of technical proof: can Plaintiff produce evidence through discovery to demonstrate that Defendant's product, as sold, meets the specific quantitative stability limitation recited in the claims (i.e., less than 5% total impurities after 15 months of storage at 5°C to 25°C)?