DCT

1:25-cv-01227

HQ Specialty Pharma Corp v. Sagent Pharmaceuticals

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-01227, D. Del., 10/03/2025
  • Venue Allegations: Venue is alleged to be proper based on Defendant's confirmation that it will not contest venue for this litigation, as well as Defendant's alleged systematic and continuous business contacts within Delaware.
  • Core Dispute: Plaintiffs allege that Defendant's submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of a calcium gluconate injection product constitutes an act of infringement of a patent covering a stable, ready-to-use formulation in a flexible container.
  • Technical Context: The technology concerns ready-to-use intravenous solutions of calcium gluconate, a drug used to treat hypocalcemia, formulated for stability and long shelf life in flexible plastic bags, which are common in hospital settings.
  • Key Procedural History: The complaint highlights a prior successful litigation involving the same patent-in-suit against Fresenius Kabi USA, LLC. In that case, a court found that Fresenius's product directly infringed the patent and that the patent was not invalid or unenforceable. The complaint alleges that Defendant's current ANDA product identifies that specific, adjudicated infringing Fresenius product as its Reference Listed Drug (RLD).

Case Timeline

Date Event
2017-07-25 ’646 Patent Priority Date
2018-10-29 Plaintiff HQ Specialty Pharma receives FDA approval for its NDA 210906
2018-11-20 ’646 Patent Issue Date
2020-12-17 Fresenius USA submits supplemental NDA for its bag product
2021-06-17 Fresenius USA receives FDA approval for its sNDA
2021-12-03 Plaintiffs file suit against Fresenius USA for infringement of the ’646 patent
2024-08-26 Jury trial begins in the Fresenius USA litigation
2025-08-01 Court enters Final Judgment against Fresenius USA, finding infringement
2025-08-21 Sagent notifies Plaintiffs of its ANDA submission via Notice Letter
2025-08-22 Fresenius USA submits the ’646 patent for listing in the Orange Book
2025-09-22 Sagent's counsel confirms it will not contest jurisdiction or venue
2025-10-03 Complaint Filing Date

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

U.S. Patent No. 10,130,646 - "Calcium Gluconate Solutions in Flexible Containers"

Issued November 20, 2018.

The Invention Explained

  • Problem Addressed: The patent's background section describes the logistical and safety challenges of administering calcium gluconate from traditional glass vials or rigid plastic bottles in a hospital setting. These challenges include the risk of breakage, the need for manual dilution into a separate IV bag (which introduces risks of contamination and dosing errors), and the resulting short shelf-life of such hospital-prepared bags (typically 45-70 days) ('646 Patent, col. 1:35-64).
  • The Patented Solution: The invention is a premixed, ready-to-use aqueous solution of calcium gluconate that is stable for long-term storage in a flexible plastic bag ('646 Patent, col. 2:8-12). The solution is "terminally sterilized" after being packaged, ensuring sterility without compromising the formulation's stability or the container's integrity ('646 Patent, col. 4:38-46). The formulation includes calcium gluconate as the active ingredient, calcium saccharate as a stabilizer to prevent precipitation, and an agent like sodium chloride to ensure the solution is isotonic, all within a specified pH range ('646 Patent, Abstract; col. 2:20-40).
  • Technical Importance: This technology provides a commercially manufactured, ready-to-administer product with a long shelf life, aiming to improve safety, efficiency, and inventory management for hospitals compared to the practice of bedside or pharmacy compounding ('646 Patent, col. 1:52-64).

Key Claims at a Glance

  • The complaint asserts infringement of claims 1, 2, and 3 of the ’646 patent (Compl. ¶36). Independent claim 1 is the broadest asserted claim.
  • Independent Claim 1 Elements:
    • A terminally sterilized aqueous calcium gluconate solution comprising:
    • sodium chloride; and
    • 1 to 15 wt. % calcium gluconate and from 1 to 19 wt. parts of calcium saccharate per 100 wt. parts of calcium gluconate
    • packaged in a flexible plastic container with the remainder water,
    • wherein the flexible plastic container is a bag, and
    • the solution has a pH of from 6 to 8.2.
  • The complaint also asserts dependent claims 2 and 3, which further narrow the formulation to specific concentrations of the components (Compl. ¶36; ’646 Patent, col. 6:66-7:5).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are Sagent's proposed generic "calcium gluconate in sodium chloride (1 g/50 mL and 2 g/100 mL) solutions," for which Sagent has submitted Abbreviated New Drug Application (ANDA) No. 219619 to the FDA for marketing approval (Compl. ¶1, 32).

Functionality and Market Context

  • The complaint alleges that Sagent's ANDA Products are intended for the same therapeutic use as Plaintiffs' product: intravenous treatment of acute symptomatic hypocalcemia (Compl. ¶18). Crucially, the complaint states that Sagent’s ANDA identifies the "Approved Fresenius Product" as the reference listed drug (RLD) (Compl. ¶32). This means Sagent has represented to the FDA that its products have the same active ingredient, dosage form, route of administration, strength, and are bioequivalent to the Fresenius product, which was previously found by a court to infringe the ’646 patent (Compl. ¶28, 33).

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

Claim Chart Summary

The complaint does not contain a claim chart exhibit, but its narrative allegations support the following infringement theory for the ’646 patent, based primarily on the alleged identity between Sagent's product and the previously adjudicated infringing Fresenius product.

U.S. Patent No. 10,130,646 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A terminally sterilized aqueous calcium gluconate solution comprising: Sagent's ANDA Products are described as aqueous calcium gluconate solutions that are bioequivalent to the RLD, which was previously found to be a terminally sterilized solution. ¶26, ¶33 col. 2:8-12
sodium chloride; and Sagent's products are identified as "calcium gluconate in sodium chloride" solutions. The RLD is alleged to contain 6.75 mg/ml of sodium chloride. ¶1, ¶26, ¶32 col. 2:25-29
1 to 15 wt. % calcium gluconate and from 1 to 19 wt. parts of calcium saccharate per 100 wt. parts of calcium gluconate The proposed concentrations (1g/50mL and 2g/100mL) equate to 2 wt.%, which is within the claimed range. The RLD is alleged to have the "required amount" of these components. ¶26, ¶32 col. 2:51-64
packaged in a flexible plastic container with the remainder water, Sagent's ANDA is for a "bag product," and the RLD is packaged in a flexible plastic container. ¶26; p. 7 heading col. 2:9-10
wherein the flexible plastic container is a bag, and Sagent's product is described as a "bag product," consistent with the RLD. ¶26; p. 7 heading col. 4:41-43
the solution has a pH of from 6 to 8.2. The RLD is alleged to be "within the required pH range," and Sagent's product is alleged to be bioequivalent. ¶26, ¶33 col. 2:30-33

Identified Points of Contention

  • Scope Questions: The core of the dispute may not center on claim scope in a traditional sense, but rather on the legal and factual consequences of Sagent's ANDA identifying a previously adjudicated infringing product as its RLD. A question for the court will be whether Sagent can plausibly argue that its proposed product is materially different from the Fresenius product in a way that avoids infringement of the asserted claims.
  • Technical Questions: A primary factual question is the degree of identity between Sagent's proposed product and the Fresenius RLD. What evidence, beyond the ANDA filing itself, demonstrates that Sagent's product will practice every limitation of Claim 1, particularly concerning the specific "calcium saccharate" used and the parameters of the "terminally sterilized" process? The complaint does not provide sufficient detail for analysis of Sagent's specific formulation or manufacturing process.

V. Key Claim Terms for Construction

Given the prior litigation against the RLD manufacturer, claim construction may be constrained by prior court rulings. However, a new defendant may seek to re-litigate key terms.

  • The Term: "terminally sterilized"

    • Context and Importance: This term defines a key manufacturing step that distinguishes the invention from products requiring aseptic filling or bedside compounding. Practitioners may focus on this term because a defendant could argue its specific sterilization method (e.g., temperature, duration, or equipment) falls outside the scope of the term as understood in the art or construed in the prior case.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification describes the process in general terms, such as "subjected to terminal sterilization via moist-heat autoclaving" and performing heat sterilization using steam ('646 Patent, col. 2:10-12, col. 4:59-61). This could support a construction covering any standard post-packaging heat sterilization process.
      • Evidence for a Narrower Interpretation: The specification provides exemplary parameters, such as "121° C. for about 20 minutes" and a range of "about 110° C. to 130° C." for 5 to 30 minutes ('646 Patent, col. 4:60-61, col. 5:1-3). A defendant might argue these examples limit the term's scope to specific time and temperature profiles that achieve sterilization without degrading the product or container.

  • The Term: "calcium saccharate"

    • Context and Importance: This is the claimed stabilizing agent. Its definition is critical because an accused infringer could use a different isomer or form of saccharate and argue it is not the same "calcium saccharate" required by the claim.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification explicitly states that while "calcium D-saccharate has been found to be particularly suitable... Other calcium saccharates may be used provided the resulting supersaturated solution is stable" ('646 Patent, col. 2:42-46). This language directly contemplates the use of forms other than calcium D-saccharate.
      • Evidence for a Narrower Interpretation: A party could argue that the term is functionally limited to only those saccharates that meet the stability criteria outlined in the patent, potentially referencing the procedure in U.S. Patent No. 1,965,535, which is incorporated by reference ('646 Patent, col. 2:46-49).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both active inducement and contributory infringement (Compl. ¶43, 44). The inducement theory is based on allegations that Sagent's proposed product labeling will instruct healthcare professionals to administer the drug, thereby directly infringing the claims (Compl. ¶41, 43). The contributory infringement theory alleges Sagent's product is especially made for an infringing use and is not a staple article of commerce suitable for substantial non-infringing use (Compl. ¶44).
  • Willful Infringement: The complaint alleges Sagent acted with full knowledge of the ’646 patent and "without reasonable basis for believing that it would not be liable for infringing" (Compl. ¶47). This allegation is explicitly supported by reference to the final judgment against Fresenius for its RLD product, suggesting Sagent was aware of the high likelihood of infringement before filing its ANDA (Compl. ¶28, 47).

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

  • A central issue will be one of factual identity and legal preclusion: to what extent is Sagent's infringement defense constrained by the prior final judgment against Fresenius, given that Sagent’s ANDA identifies the adjudicated infringing Fresenius product as its Reference Listed Drug?
  • A key question on the merits will be one of infringement by imitation: does Sagent's proposed product, which it has represented to the FDA as bioequivalent to the reference product, contain any material technical distinctions in its formulation or manufacturing process that would allow it to avoid the infringement findings from the prior litigation?
  • The analysis of damages and willfulness will likely turn on a question of objective reasonableness: in light of the public court record finding the reference product to be infringing, what good-faith basis could Sagent present for its belief that its own bioequivalent product would not infringe the ’646 patent?