American Regent Inc v. Endo Operations Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: American Regent, Inc. (New York)
  • Defendant: Endo Operations Limited (Ireland)
  • Plaintiff’s Counsel: GIBBONS P.C.; Sterne, Kessler, Goldstein & Fox P.L.L.C.
• Case Identification: 2:25-cv-11945, D.N.J., 06/18/2025
• Venue Allegations: Venue is alleged to be proper in the District of New Jersey because Defendant Endo Operations Limited maintains a regular and established place of business in Woodcliff Lake, New Jersey.
• Core Dispute: Plaintiff alleges that Defendant’s submission of an Abbreviated New Drug Application (ANDA) to the FDA for generic versions of Plaintiff's Tralement® and Multrys® products constitutes an act of infringement of five U.S. patents directed to trace element compositions for parenteral nutrition.
• Technical Context: The technology involves stable, injectable formulations of essential trace elements (zinc, copper, manganese, selenium) used to provide nutrition to patients who cannot receive it orally or enterally.
• Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendant’s notification to Plaintiff, via a letter dated May 14, 2025, of its filing of an ANDA containing a Paragraph IV Certification. The certification asserts that the patents-in-suit, which are listed in the FDA’s Orange Book for the Tralement® and Multrys® products, will not be infringed by Defendant's proposed generic products.

Case Timeline

Date	Event
2020-07-02	Earliest Priority Date for all Patents-in-Suit
2020-07-02	FDA Approval of Plaintiff's Tralement® and Multrys®
2023-10-17	U.S. Patent No. 11,786,548 Issues
2024-05-07	U.S. Patent No. 11,975,022 Issues
2024-06-04	U.S. Patent No. 11,998,565 Issues
2024-11-26	U.S. Patent No. 12,150,956 Issues
2024-11-26	U.S. Patent No. 12,150,957 Issues
2025-05-14	Defendant Sends Paragraph IV Notice Letter
2025-06-18	Complaint Filing Date

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

U.S. Patent No. 11,786,548 - Trace element compositions, methods of making and use

• Patent Identification: U.S. Patent No. 11,786,548, "Trace element compositions, methods of making and use," issued October 17, 2023. (Compl. ¶23).

The Invention Explained

• Problem Addressed: The patent describes that when trace elements are added to parenteral nutrition (PN) solutions, the resulting admixture often has a short stability period of only 24 to 48 hours at room temperature. This necessitates frequent, costly, and time-consuming preparation of PN doses, increases waste, and can lead to drug supply shortages. (’548 Patent, col. 2:3-24).
• The Patented Solution: The invention is a stable, injectable composition containing specific concentrations of zinc, copper, selenium, and manganese that, when added to a PN solution, creates an admixture that remains stable for a significantly longer period (e.g., at least 3 to 14 days under refrigeration). This allows for doses to be prepared in larger batches and less frequently. (’548 Patent, Abstract; col. 2:31-44). The solution is further defined by what it lacks, including added chromium and vitamins. (’548 Patent, col. 12:45-65, Claim 1).
• Technical Importance: This approach improves the quality of life for patients and caregivers by reducing the frequency of admixing and trips to healthcare facilities, and it lowers overall healthcare costs and waste. (’548 Patent, col. 2:31-38).

Key Claims at a Glance

• The complaint asserts infringement of one or more claims without specifying which claims are asserted (Compl. ¶43). Independent claim 1 is a representative composition claim.
• Essential elements of Independent Claim 1:
  • An injectable composition comprising water, about 60 µg of selenium, 3,000 µg of zinc, about 300 µg of copper, and about 55 µg of manganese per 1 mL of the injectable composition;
  • wherein the injectable composition contains 0 µg per 1 mL to about 10 µg per 1 mL of iron;
  • does not contain any vitamins;
  • contains no added chromium; and
  • no aluminum or aluminum in an amount not to exceed 6 µg per 1 mL of the injectable composition.

U.S. Patent No. 11,975,022 - Trace element compositions, methods of making and use

• Patent Identification: U.S. Patent No. 11,975,022, "Trace element compositions, methods of making and use," issued May 7, 2024. (Compl. ¶26).

The Invention Explained

• Problem Addressed: This patent addresses the same technical problem of short stability periods for parenteral nutrition admixed with trace elements as the ’548 Patent. (’022 Patent, col. 1:11-2:24).
• The Patented Solution: The patent claims a method of providing trace elements by administering an injectable composition with the same specific concentrations of zinc, copper, selenium, and manganese, and the same negative limitations (e.g., no added chromium), as recited in the ’548 Patent. The claimed method provides a stable source of essential trace elements for patients requiring parenteral nutrition. (’022 Patent, Abstract; col. 4:56-65, Claim 1).
• Technical Importance: This patented method provides a framework for administering a trace element formulation that enables less frequent preparation of parenteral nutrition, thereby improving patient quality of life and reducing healthcare costs. (’022 Patent, col. 2:31-38).

Key Claims at a Glance

• The complaint asserts infringement of one or more claims without specifying which claims are asserted (Compl. ¶50). Independent claim 1 is a representative method of treatment claim.
• Essential elements of Independent Claim 1:
  • A method of providing trace elements to a patient in need thereof;
  • the method comprising administering an injectable trace element composition to the patient;
  • the composition comprising water, about 60 µg of selenium, about 3,000 µg of zinc, about 300 µg of copper, and about 55 µg of manganese per 1 mL;
  • wherein the composition contains 0 µg per 1 mL to about 10 µg per 1 mL of iron, does not contain any vitamins, contains no added chromium, and no aluminum or aluminum in an amount not to exceed 6 µg per 1 mL.

Multi-Patent Capsule: U.S. Patent No. 11,998,565

• Patent Identification: U.S. Patent No. 11,998,565, "Trace element compositions, methods of making and use," issued June 4, 2024. (Compl. ¶28).
• Technology Synopsis: The patent claims a method of administering a stable injectable trace element composition to provide parenteral nutrition. The claimed composition contains specific amounts of zinc, copper, selenium, and manganese and is characterized by the absence of added chromium. (’565 Patent, Abstract).
• Asserted Claims: One or more claims. (Compl. ¶56).
• Accused Features: The administration of Defendant's proposed generic version of Tralement®, which allegedly contains the same or equivalent amounts of the claimed trace elements, is accused of infringing this patent. (Compl. ¶¶ 37-39, 56).

Multi-Patent Capsule: U.S. Patent No. 12,150,956

• Patent Identification: U.S. Patent No. 12,150,956, "Trace element compositions, methods of making and use," issued November 26, 2024. (Compl. ¶30).
• Technology Synopsis: The patent claims a method of administering a stable injectable trace element composition specifically for pediatric or neonatal patients. This formulation contains different concentrations of trace elements (1,000 µg zinc, 60 µg copper, 6 µg selenium, and 3 µg manganese per 1 mL) suited for this patient population. (’956 Patent, Abstract; col. 4:32-37, Claim 1).
• Asserted Claims: One or more claims. (Compl. ¶62).
• Accused Features: The administration of Defendant's proposed generic version of Multrys®, which is formulated for neonatal and pediatric patients and allegedly contains the same or equivalent amounts of the claimed trace elements, is accused of infringing this patent. (Compl. ¶¶ 37-39, 62).

Multi-Patent Capsule: U.S. Patent No. 12,150,957

• Patent Identification: U.S. Patent No. 12,150,957, "Trace element compositions, methods of making and use," issued November 26, 2024. (Compl. ¶32).
• Technology Synopsis: The patent claims a stable injectable composition, rather than a method, specifically formulated for pediatric or neonatal patients. The claimed composition contains 1,000 µg zinc, 60 µg copper, 6 µg selenium, and 3 µg manganese per 1 mL. (’957 Patent, Abstract; col. 12:45-53, Claim 1).
• Asserted Claims: One or more claims. (Compl. ¶68).
• Accused Features: Defendant's proposed generic version of Multrys®, which is formulated for neonatal and pediatric patients and allegedly contains the same or equivalent amounts of the claimed trace elements, is accused of infringing this patent. (Compl. ¶¶ 37-39, 68).

III. The Accused Instrumentality

No probative visual evidence provided in complaint.

Product Identification

• Defendant's ANDA Products, which are proposed generic versions of Plaintiff's Tralement® and Multrys® drug products. (Compl. ¶1).

Functionality and Market Context

• The complaint alleges, based on Defendant's notice letter, that the ANDA Products are injectable trace element solutions with two distinct formulations:
  • One formulation, corresponding to Tralement®, contains 3 mg Zn/mL, 0.3 mg Cu/mL, 55 mcg Mn/mL, and 60 mcg Se/mL. (Compl. ¶38). This product is indicated for adult and pediatric patients weighing at least 10 kg. (Compl. ¶19).
  • A second formulation, corresponding to Multrys®, contains 1000 mcg Zn/mL, 60 mcg Cu/mL, 3 mcg Mn/mL, and 6 mcg Se/mL. (Compl. ¶38). This product is indicated for neonatal and pediatric patients weighing less than 10 kg. (Compl. ¶21).
• The complaint alleges these products contain the same or equivalent active ingredients as Plaintiff's branded products and will be used as a source of trace elements for parenteral nutrition. (Compl. ¶¶ 37, 39).

IV. Analysis of Infringement Allegations

11,786,548 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
An injectable composition comprising water, about 60 µg of selenium, 3,000 µg of zinc, about 300 µg of copper, and about 55 µg of manganese per 1 mL of the injectable composition	Defendant's product is an injectable composition containing 60 mcg Se/mL, 3 mg (3,000 µg) Zn/mL, 0.3 mg (300 µg) Cu/mL, and 55 mcg Mn/mL.	¶38	col. 4:26-29
wherein the injectable composition contains 0 µg per 1 mL to about 10 µg per 1 mL of iron	On information and belief, the ANDA product contains ingredients that are the same as or equivalent to Plaintiff's product, which meets this limitation.	¶39	col. 12:49-50
does not contain any vitamins	On information and belief, the ANDA product is a trace element composition that does not contain vitamins.	¶39	col. 12:51
contains no added chromium	On information and belief, the ANDA product contains no added chromium as an active ingredient.	¶39	col. 12:52
and no aluminum or aluminum in an amount not to exceed 6 µg per 1 mL of the injectable composition.	On information and belief, the ANDA product meets this limitation on aluminum content.	¶39	col. 12:53-55

11,975,022 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method of providing trace elements to a patient in need thereof, the method comprising administering an injectable trace element composition to the patient	Defendant's proposed package insert allegedly instructs medical professionals to administer the accused product to patients requiring parenteral nutrition.	¶50	col. 4:56-59
the injectable composition comprising water, about 60 µg of selenium, about 3,000 µg of zinc, about 300 µg of copper, and about 55 µg of manganese per 1 mL	Defendant's product is an injectable composition containing 60 mcg Se/mL, 3 mg (3,000 µg) Zn/mL, 0.3 mg (300 µg) Cu/mL, and 55 mcg Mn/mL.	¶38	col. 4:60-63
wherein the injectable composition contains 0 µg per 1 mL to about 10 µg per 1 mL of iron, does not contain any vitamins, contains no added chromium, and no aluminum or aluminum in an amount not to exceed 6 µg per 1 mL	On information and belief, the ANDA product meets these specified limitations on iron, vitamins, chromium, and aluminum.	¶39	col. 4:64-67

Identified Points of Contention

• Scope Questions: The complaint alleges infringement based on the accused products containing the "same or equivalent" ingredients. A central question for the court will be whether the specific formulation and impurity profile of Defendant's ANDA product, as manufactured, falls within the scope of the claims. This is particularly relevant for the negative limitations, such as "no added chromium" and the specific upper limits for iron and aluminum.
• Technical Questions: A key evidentiary question will be what the actual impurity profile of Defendant's manufactured product is. The complaint does not provide this data, relying on "information and belief." Discovery will be required to determine if trace amounts of chromium, iron, or aluminum are present from manufacturing processes or raw materials, and whether those amounts exceed the claimed thresholds.

V. Key Claim Terms for Construction

The Term: "about" (e.g., "about 3,000 µg of zinc")

• Context and Importance: This term appears before each recited concentration of the active ingredients in the asserted independent claims. Its construction will define the permissible range of deviation from the specified amounts for a finding of literal infringement. Practitioners may focus on this term because the Defendant's product formulation matches the recited numbers exactly (e.g., 3 mg/mL vs. 3,000 µg/mL), but manufacturing variability could be a factor, making the scope of "about" critical for both literal infringement and the doctrine of equivalents.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification discloses various ranges for the trace elements, which may support a construction that "about" is not limited to the precise number recited but encompasses a functional or reasonable range. (’548 Patent, col. 3:65 - col. 4:5).
  • Evidence for a Narrower Interpretation: The claims recite highly specific values (e.g., "55 µg of manganese"), and the patent provides tables with these exact concentrations for its primary embodiments. This may suggest that "about" is intended to cover only minor variations inherent in manufacturing and measurement, not a broad numerical range. (’548 Patent, Table 1, col. 11:15-21).

The Term: "no added chromium"

• Context and Importance: This negative limitation is a key feature distinguishing the claimed invention from prior art multi-trace element formulations that included chromium. Its construction will determine whether the mere presence of any detectable chromium, even as an unintended impurity, avoids infringement. Practitioners may focus on this term because it is common for pharmaceutical manufacturing processes to introduce trace contaminants not listed as active ingredients.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation (i.e., less restrictive): The specification distinguishes between intentionally added components and elemental impurities. One might argue "no added chromium" means chromium is not included as an active ingredient, while still permitting its presence as an incidental impurity below a certain threshold. The patent's own discussion of acceptable limits for other elemental impurities could support this view. (’548 Patent, Table 4, col. 15-16).
  • Evidence for a Narrower Interpretation (i.e., more restrictive): The plain language suggests a strict prohibition. The patent repeatedly emphasizes providing a chromium-free formulation for patients who do not require it. (’548 Patent, col. 2:45-49). This could support a construction where any detectable amount of chromium resulting from the manufacturing of the final composition would place the product outside the claim scope.

VI. Other Allegations

Indirect Infringement

• The complaint alleges induced and contributory infringement for the asserted method claims (e.g., in the ’022, ’565, and ’956 patents). Inducement is based on the allegation that Defendant's proposed product labeling will instruct medical professionals and patients to administer the ANDA Products in an infringing manner, with Defendant's knowledge and specific intent to cause infringement. (Compl. ¶¶ 50, 56, 62, 68). Contributory infringement is based on the allegation that the ANDA Products are especially made for an infringing use and are not suitable for a substantial non-infringing use. (Compl. ¶¶ 51, 57, 63, 69).

Willful Infringement

• The complaint does not use the term "willful infringement" but alleges that Defendant had knowledge of the patents-in-suit "since at least the date Endo submitted the ANDA" and was aware that the submission constituted an act of infringement. (Compl. ¶46). This allegation, combined with the request for a finding that the case is "exceptional" under 35 U.S.C. § 285, forms the basis for a potential future claim of willfulness. (Compl. ¶47).

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

• A core issue will be one of evidentiary proof for negative limitations: Can Plaintiff demonstrate through discovery that Defendant's ANDA products, as specified and manufactured, will necessarily contain "no added chromium" and will not exceed the claimed trace limits for iron and aluminum? The outcome may depend heavily on the specifics of Defendant's manufacturing process and quality control.
• A central question of claim construction will be the scope of the term "about." Given the direct numerical correspondence between the claims and the accused product's formulation, the interpretation of "about" will be critical in defining the boundaries of literal infringement, especially in the context of normal manufacturing variances.
• A key question for the asserted method claims will be one of induced infringement: Does the language in Defendant's proposed product label actively instruct and encourage medical professionals to perform the specific steps of "administering" the composition in a manner that meets all limitations of the asserted method claims, thereby demonstrating the specific intent required for inducement?