DCT

1:25-cv-01523

Hope Medical Enterprises Inc v. Somerset Therap LLC

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-01523, D. Del., 12/17/2025
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because three of the four defendant entities are organized under the laws of Delaware and reside in the district. For the foreign defendant, Somerset Private, venue is alleged based on its subjection to personal jurisdiction in the district.
  • Core Dispute: Plaintiff alleges that Defendants’ submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of Plaintiff's Sodium Thiosulfate Injection constitutes an act of infringement of four U.S. patents directed to high-purity pharmaceutical compositions.
  • Technical Context: The technology concerns pharmaceutical-grade sodium thiosulfate compositions with specific, low levels of impurities, intended for human injection as an antidote for acute cyanide poisoning.
  • Key Procedural History: The patents-in-suit are listed in the FDA's "Orange Book" in connection with Plaintiff's New Drug Application (NDA No. 203923). The lawsuit was initiated in response to Defendants' notice letter, which included a Paragraph IV certification asserting that the patents-in-suit are invalid, unenforceable, or will not be infringed by their proposed generic product. The complaint was filed within the 45-day statutory window, which triggers an automatic stay of up to 30 months on the FDA's approval of Defendants' ANDA.

Case Timeline

Date Event
2009-07-08 Earliest Patent Priority Date (’973, ’724, ’301, ’813 Patents)
2012-02-14 FDA approves Plaintiff's NDA Product
2012-01-01 Plaintiff commences commercial sales of its NDA Product
2013-07-30 U.S. Patent No. 8,496,973 issues
2016-05-24 U.S. Patent No. 9,345,724 issues
2023-09-12 U.S. Patent No. 11,753,301 issues
2025-05-20 U.S. Patent No. 12,304,813 issues
2025-11-03 Defendants send Paragraph IV notice letter to Plaintiff
2025-12-17 Complaint filed

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

U.S. Patent No. 11,753,301 - Sodium Thiosulfate-Containing Pharmaceutical Compositions, issued September 12, 2023

The Invention Explained

  • Problem Addressed: The patent's background section describes a need for sodium thiosulfate raw material that meets new, more stringent FDA quality standards for use in new pharmaceutical products. It notes that currently available raw material is unsuitable and that there is a lack of an effective analytical method to determine certain impurities, such as total non-purgeable organic carbon (NPOC), in sodium thiosulfate samples (’301 Patent, col. 2:50-65).
  • The Patented Solution: The invention provides a highly purified, "pharmaceutical grade" sodium thiosulfate composition defined by maximum allowable levels for a host of specific impurities, including NPOC, mercury, aluminum, and selenium (’301 Patent, Abstract; col. 3:25-44). The specification also discloses methods for producing this high-purity material and a novel analytical method for accurately measuring NPOC in such samples, which overcomes issues with conventional techniques (’301 Patent, col. 4:63-65; col. 3:49-62).
  • Technical Importance: The development of this high-purity composition and its associated analytical methods enables the creation of new, FDA-approved clinical therapies using sodium thiosulfate that can satisfy modern regulatory requirements for safety and purity (’301 Patent, col. 2:58-62).

Key Claims at a Glance

  • The complaint alleges infringement of one or more claims without specifying which ones (Compl. ¶66). Independent claim 1 is representative of the composition claims.
  • Independent Claim 1: A composition claim for "Pharmaceutical grade sodium thiosulfate" which is characterized by meeting numerous specific purity and physical property limitations, including:
    • no greater than about 10 ppm of non-purgeable organic carbon
    • no greater than about 0.05 ppm of mercury
    • no greater than about 2 ppm of aluminum
    • no greater than about 0.003% by weight of selenium
    • assaying between about 98% and 102% sodium thiosulfate on an anhydrous basis via ion chromatography
    • a heavy metal content of no greater than about 10 ppm
    • a total aerobic microbial load of no greater than about 100 CFU/g
    • a pH between about 6.0 and about 8.0 in a 10% aqueous solution
    • numerous other limits on impurities such as chloride, sulfide, iron, calcium, potassium, sulfite, and sulfate

U.S. Patent No. 12,304,813 - Sodium Thiosulfate-Containing Pharmaceutical Compositions, issued May 20, 2025

The Invention Explained

  • Problem Addressed: As with the related ’301 Patent, this patent addresses the need for sodium thiosulfate compositions that meet heightened FDA purity standards for new pharmaceutical applications (’813 Patent, col. 2:50-55).
  • The Patented Solution: The invention claims a "unit-dosage form" that incorporates the highly purified sodium thiosulfate. The claims define the dosage form by reference to the same set of stringent impurity limits for the active pharmaceutical ingredient as described in the ’301 patent family (’813 Patent, Abstract; col. 5:1-3).
  • Technical Importance: This patent extends the protection for the high-purity sodium thiosulfate composition to its practical application in a finished, packaged drug product, securing the invention as it would be sold and administered to patients (’813 Patent, col. 15:39-49).

Key Claims at a Glance

  • The complaint alleges infringement of one or more claims without specifying which ones (Compl. ¶74). Independent claim 1 is representative.
  • Independent Claim 1: A claim directed to a "unit-dosage form comprising pharmaceutical grade sodium thiosulfate," which is defined by the same list of purity and property limitations for the sodium thiosulfate active ingredient as found in claim 1 of the ’301 Patent, including limits on NPOC, mercury, aluminum, selenium, heavy metals, microbial load, and others.

U.S. Patent No. 8,496,973 ('973 Patent) - Sodium Thiosulfate-Containing Pharmaceutical Compositions

  • Patent Identification: U.S. Patent No. 8,496,973, "Sodium Thiosulfate-Containing Pharmaceutical Compositions," issued July 30, 2013 (Compl. ¶41).
  • Technology Synopsis: As a member of the same patent family as the ’301 and ’813 patents, this patent is directed to highly purified sodium thiosulfate compositions suitable for pharmaceutical use, defined by specific low levels of various impurities. The invention addresses the need for raw materials that meet modern, stringent FDA quality standards.
  • Asserted Claims: One or more claims (Compl. ¶50).
  • Accused Features: The "Somerset ANDA Product," which is a proposed generic sodium thiosulfate injection (Compl. ¶50).

U.S. Patent No. 9,345,724 ('724 Patent) - Sodium Thiosulfate-Containing Pharmaceutical Compositions

  • Patent Identification: U.S. Patent No. 9,345,724, "Sodium Thiosulfate-Containing Pharmaceutical Compositions," issued May 24, 2016 (Compl. ¶43).
  • Technology Synopsis: As a member of the same patent family, this patent is also directed to high-purity sodium thiosulfate compositions suitable for pharmaceutical use, characterized by specific impurity profiles that meet heightened regulatory standards.
  • Asserted Claims: One or more claims (Compl. ¶58).
  • Accused Features: The "Somerset ANDA Product," a proposed generic sodium thiosulfate injection (Compl. ¶58).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is the "Somerset ANDA Product," identified as a proposed generic version of "Sodium Thiosulfate Injection, 250 mg/mL" in a single-dose vial (Compl. ¶9).

Functionality and Market Context

  • The Somerset ANDA Product is intended to be a generic equivalent of Hope's NDA Product (No. 203923), which is approved for use in treating acute cyanide poisoning (Compl. ¶7, 11). By filing the ANDA, Defendants have represented to the FDA that their product is bioequivalent to Hope's approved product (Compl. ¶13). The filing of the ANDA signifies Defendants' intent to commercially manufacture, use, and sell this generic drug in the United States upon receiving FDA approval, thereby competing with Plaintiff's branded product (Compl. ¶9-10). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not contain a claim chart or detailed, element-by-element infringement allegations. The infringement claim is the statutory act of submitting an ANDA for a drug claimed in a patent under 35 U.S.C. § 271(e)(2) (Compl. ¶50). The substantive allegation is that the product described in Defendants' ANDA, if commercially manufactured, would meet all limitations of the asserted claims.

'301 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
Pharmaceutical grade sodium thiosulfate which contains no greater than about 10 ppm of non-purgeable organic carbon... The Somerset ANDA Product is alleged to be a sodium thiosulfate injection that, as a proposed bioequivalent generic for human use, will necessarily be formulated with pharmaceutical grade sodium thiosulfate meeting this purity limitation. ¶9, 13, 66 col. 9:10-18
...contains no greater than about 0.05 ppm of mercury... The Somerset ANDA Product is alleged to be formulated with sodium thiosulfate that meets this specific mercury impurity limit. ¶9, 13, 66 col. 9:30-34
...contains no greater than about 2 ppm of aluminum... The Somerset ANDA Product is alleged to be formulated with sodium thiosulfate that meets this specific aluminum impurity limit. ¶9, 13, 66 col. 9:39-45
...has a pH between about 6.0 and about 8.0. The Somerset ANDA Product, as a proposed bioequivalent injectable solution, is alleged to have a pH within the claimed range. ¶9, 13, 66 col. 7:25-31

'813 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A unit-dosage form comprising pharmaceutical grade sodium thiosulfate... The Somerset ANDA Product is described as a "single-dose vial," which is alleged to be a unit-dosage form. ¶9, 13, 74 col. 15:35-43
...which contains no greater than about 10 ppm of non-purgeable organic carbon... The sodium thiosulfate active ingredient within the Somerset ANDA Product is alleged to meet this and all other recited purity limitations, based on its status as a proposed bioequivalent generic drug for human injection. ¶9, 13, 74 col. 11:1-5
...has a total aerobic count of microbial load of no greater than about 100 CFU/g... The sodium thiosulfate active ingredient within the Somerset ANDA Product is alleged to meet this specific microbial limit. ¶9, 13, 74 col. 11:14-17

Identified Points of Contention

  • Factual Questions: The central dispute will be factual: does the product formulation described in Somerset’s confidential ANDA actually meet every single, specific numerical limitation recited in the asserted claims? For example, what evidence does the ANDA provide regarding the level of NPOC, mercury, aluminum, and dozens of other specified impurities in its sodium thiosulfate active pharmaceutical ingredient?
  • Scope Questions: The case may raise questions about the scope of the term "about" as applied to the numerous numerical thresholds in the claims. The dispute may focus on whether Defendants' product, if its impurity levels are measured to be just outside a recited numerical limit (e.g., 11 ppm of NPOC versus a claim limit of "about 10 ppm"), still falls within the scope of the claims.

V. Key Claim Terms for Construction

The Term: "pharmaceutical grade sodium thiosulfate"

  • Context and Importance: This term, appearing in the preamble of claim 1 of the ’301 Patent, may be argued to be limiting. Its construction is important because it could set a baseline quality standard that an accused product must meet, independent of the specific limitations in the claim body. Practitioners may focus on this term to dispute whether it is merely a statement of intended use or a structurally defining characteristic of the claimed composition.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification defines the term as sodium thiosulfate "manufactured according to Good Manufacturing Practices (GMP) as detailed in the United States Code of Federal Regulations 21 CFR 211 and meets one or more of the purity levels recited herein" (’301 Patent, col. 6:21-26). This could support an interpretation tied to regulatory standards and function rather than just the claim's explicit list of limitations.
    • Evidence for a Narrower Interpretation: A defendant may argue the term is defined exhaustively by the list of specific purity thresholds recited in the body of the claim itself, rendering the preamble redundant or non-limiting.

The Term: "about"

  • Context and Importance: This term precedes nearly every numerical limitation in the asserted claims (e.g., "about 10 ppm," "about 0.05 ppm"). Its interpretation will be critical to determining the boundary of infringement. If Somerset's product has an impurity level slightly above a recited number, the scope of "about" will determine whether that product infringes.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states that "'about' or 'approximately' means an acceptable error for a particular value as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined" (’301 Patent, col. 5:62-65). This language suggests a flexible, context-dependent range that could be informed by expert testimony.
    • Evidence for a Narrower Interpretation: The specification also provides detailed analytical methods for measuring impurities, including specific instrumentation (e.g., the InnovOx laboratory TOC Analyzer) (’301 Patent, col. 13:66-14:2; Example 2). A party could argue the scope of "about" should be limited to the known precision or standard deviation of these specific measurement techniques.

VI. Other Allegations

Indirect Infringement

  • The complaint alleges induced and contributory infringement for all four patents-in-suit. The basis for inducement is the allegation that Defendants, upon approval, will market their ANDA product and "intentionally encourage acts of direct infringement" by end-users (e.g., physicians and patients), with knowledge of the patents (Compl. ¶53, 61, 69, 77). The basis for contributory infringement is the allegation that the Somerset ANDA Product is "especially adapted for a use that infringes" and has "no substantial non-infringing use" (Compl. ¶54, 62, 70, 78).

Willful Infringement

  • The complaint does not explicitly use the word "willful" in its infringement counts. However, the prayer for relief requests a judgment that this is an "exceptional case pursuant to 35 U.S.C. § 285," which is a request for attorneys' fees (Prayer for Relief, ¶(j)). Any argument for enhanced damages or fees would be based on Defendants' alleged knowledge of the patents, evidenced at least by the Paragraph IV certification and notice letter sent prior to the lawsuit (Compl. ¶9, 14).

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

  • A core issue will be one of evidentiary proof: does the chemical composition of the product described in Defendants' confidential ANDA, and the product that would be manufactured under it, fall within the precise and numerous numerical purity ranges required by the asserted claims? The outcome will depend heavily on discovery into Defendants' application and manufacturing processes.
  • A key legal question will be one of claim scope: how will the court construe the term "about" as applied to the dozens of quantitative limitations in the claims? The resolution of this issue will define the infringement boundary and may determine the outcome for a product with impurity levels that are close to, but not identical to, the recited values.
  • A central question for the defense will be one of patent validity: can Defendants prove by clear and convincing evidence that the patents' claims to compositions with specific purity profiles are invalid as anticipated or obvious in light of prior art sodium thiosulfate formulations, despite the patent's assertion that it represents a new, higher standard of purity?