American Regent v. Fresenius Kabi: Selenious Acid Injection Patent Dismissed Without Prejudice
American Regent filed suit against Fresenius Kabi in the District of New Jersey asserting US11998565B2 covering selenious acid injection formulations used for intravenous selenium supplementation. The parties stipulated to dismiss all claims and counterclaims without prejudice under Rule 41 in just 141 days — leaving the door open for future litigation.
Pharma injection patent dispute ends in no-strings dismissal after five months
On 16 July 2024, American Regent, Inc. filed a patent infringement action against Fresenius Kabi USA, LLC in the United States District Court for the District of New Jersey (Case No. 2:24-cv-07801). The suit asserted US11998565B2, a patent covering selenious acid injection formulations, against Fresenius Kabi’s competing selenious acid injection products offered at multiple selenium concentration levels, including 600 mcg/10 mL and 60 mcg/mL presentations.
The case closed on 4 December 2024, just 141 days after filing, when both parties jointly stipulated to dismiss all claims, counterclaims, and affirmative defenses without prejudice under Federal Rules of Civil Procedure 41(a)(1) and 41(c). Critically, neither party was required to pay costs, disbursements, or attorneys’ fees. A dismissal without prejudice means the action was terminated on procedural grounds, not the merits, and American Regent retains the right to refile substantially the same claims in future proceedings.
The speed of resolution — under five months — is notably rapid for pharmaceutical patent litigation in New Jersey, a jurisdiction that routinely sees protracted Hatch-Waxman and branded-generic disputes. The public record does not disclose the commercial terms, if any, underlying the stipulation, leaving open whether a licensing arrangement, supply agreement, or strategic reassessment drove the parties’ agreement. The without-prejudice posture suggests ongoing commercial sensitivity around the patent and Fresenius Kabi’s selenious acid product line.
Filing to Dismissed without Prejudice in 141 days
141 days — resolved well before typical ANDA/pharma district court trials, which often run 2–4 years
Dismissed without prejudice: what the Rule 41 stipulation means for both parties
Rule 41(a)(1) dismissal: no merits, no bar to refiling
A stipulated dismissal under Federal Rule of Civil Procedure 41(a)(1) terminates the action by mutual agreement of the parties without any adjudication on the merits. Because the dismissal is without prejudice, it does not operate as res judicata. American Regent is not barred from asserting US11998565B2 against Fresenius Kabi again, provided applicable statutes of limitations and other procedural requirements are satisfied.
No merits rulingWithout prejudice vs. with prejudice: a meaningful difference
A dismissal without prejudice leaves the plaintiff’s legal position intact — claims survive and may be refiled. A dismissal with prejudice, by contrast, extinguishes the claims permanently and acts as a final judgment on the merits. Here, the stipulation expressly states without prejudice, so Fresenius Kabi has not obtained a final disposition of the infringement allegations. The public record does not disclose any underlying settlement terms or licensing arrangement that may have informed this choice.
Claims surviveAmerican Regent retains enforcement optionality on US11998565B2
By dismissing without prejudice, American Regent preserves its ability to re-assert its selenious acid injection patent against Fresenius Kabi or any other party. This posture is consistent with a plaintiff that may be monitoring the competitor’s commercial activity, evaluating claim scope, or negotiating a commercial resolution outside the court record. No injunction, damages award, or formal finding of non-infringement was entered.
Enforcement preservedFresenius Kabi escapes judgment but faces lingering patent risk
Fresenius Kabi obtained no declaratory judgment of non-infringement or invalidity of US11998565B2. The absence of any merits ruling means its selenious acid injection products remain potentially subject to future infringement claims under the same patent. Competitors and supply chain partners relying on Fresenius Kabi’s selenious acid presentations should note that the patent risk cloud has not been formally cleared by this dismissal.
No clearance obtainedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | American Regent, Inc. | Company | Pharmaceutical manufacturer — holder of US11998565B2 covering selenious acid injection formulationsSearch in Eureka ↗ |
| Defendant | Fresenius Kabi | Individual | Fresenius Kabi USA, LLC — global generic and specialty injectable drug manufacturerSearch in Eureka ↗ |
| Plaintiff counsel | Charles H. Chevalier | Attorney | Counsel for American Regent, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Christine A. Gaddis | Attorney | Counsel for American Regent, Inc.Search in Eureka ↗ |
| Plaintiff counsel | Dennies Varughese | Attorney | Counsel for American Regent, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Gibbons PC | Law Firm | Representing American Regent, Inc.Search in Eureka ↗ |
| Plaintiff law firm | Sterne Kessler Goldstein & Fox | Law Firm | Representing American Regent, Inc.Search in Eureka ↗ |
| Defendant counsel | James S. Richter | Attorney | Counsel for Fresenius KabiSearch in Eureka ↗ |
| Defendant law firm | MIDLIGE RICHTER LLC | Law Firm | Representing Fresenius KabiSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | New Jersey District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulated dismissal expressly invokes Rules 41(a)(1) and 41(c), confirming that both parties — including Fresenius Kabi’s counterclaims — are extinguished procedurally, not on the merits. The without-prejudice qualifier is legally significant: it forecloses any res judicata or issue preclusion argument by Fresenius Kabi in subsequent proceedings. The mutual waiver of costs and fees indicates a balanced negotiating outcome, consistent with a negotiated resolution rather than one party conceding weakness. No claim construction, preliminary injunction, or substantive motion appears to have been decided, meaning the scope of US11998565B2 remains entirely undetermined by this court.
US11998565B2 — Selenious Acid Injection for Intravenous Selenium Supplementation
US11998565B2, filed under application number US18/124391, protects selenious acid injection formulations used to deliver selenium intravenously — a critical trace element in parenteral nutrition protocols for patients who cannot absorb nutrients orally. The patent’s coverage appears directed at specific concentration parameters of selenious acid in injectable form, which is clinically significant given that selenium dosing in IV nutrition requires precise formulation to avoid toxicity while maintaining therapeutic efficacy.
American Regent’s assertion of this patent against Fresenius Kabi’s multiple selenium concentration presentations suggests the company views US11998565B2 as a broad formulation patent capable of covering a range of commercial selenious acid products. For the intravenous nutrition and specialty injectable sector, this patent represents a meaningful barrier to generic and competitor entry in a niche but clinically essential product category. Any manufacturer active in parenteral micronutrient solutions should evaluate their selenious acid formulation against this patent’s claim language.
Should your team run an FTO against US11998565B2?
If your organisation develops, manufactures, imports, or distributes selenious acid injection products — including any parenteral selenium supplementation formulation — US11998565B2 warrants direct FTO scrutiny. The without-prejudice dismissal in this case provides no legal clearance for Fresenius Kabi or any third party. American Regent’s patent remains in force, and the company has demonstrated a willingness to assert it against a major injectable pharmaceutical manufacturer.
PatSnap Eureka’s FTO Search Agent can map US11998565B2’s independent and dependent claims against your specific formulation parameters — including selenium concentration, vehicle composition, and dosage volume — to identify genuine freedom-to-operate gaps or design-around opportunities. Eureka also tracks the prosecution history of US18/124391 to surface any file wrapper estoppel constraints that may narrow or expand the patent’s enforceable scope against your product.
Run a freedom-to-operate analysis on US11998565B2 to assess your product’s exposure
Run FTO in Eureka →Similar injectable pharmaceutical patent cases in D.N.J. and related courts
Explore comparable patent infringement actions involving specialty injectable and parenteral nutrition formulations filed in the District of New Jersey and related federal courts.
What this case signals for the injectable pharmaceutical IP landscape
A rapid without-prejudice dismissal in a specialty injectable patent case rarely signals the end of the story — it typically signals a pause.
Without-prejudice exits in pharma often precede licensing or re-filing
When branded pharmaceutical plaintiffs dismiss infringement suits without prejudice and without costs this quickly, it frequently suggests behind-the-scenes commercial negotiation rather than a concession on patent strength. IP teams tracking American Regent’s enforcement posture on US11998565B2 should monitor for new filings or licensing disclosures over the next 12–24 months.
Selenious acid injection is an active competitive battleground
The involvement of multiple selenium concentration products — 600 mcg/10 mL, 60 mcg/mL, and 12 mcg/2 mL presentations — indicates that American Regent is asserting broad coverage across the selenious acid injectable market. Companies developing or distributing competing formulations should treat US11998565B2 as an active enforcement risk requiring careful FTO analysis.
American v Fresenius — key questions answered
The case was dismissed without prejudice on 4 December 2024. Both parties stipulated under Federal Rules of Civil Procedure 41(a)(1) and 41(c) to dismiss all claims, counterclaims, and affirmative defenses, with no costs or attorneys’ fees awarded to either party. No merits ruling was issued.
American Regent asserted US11998565B2, filed under application number US18/124391, which covers selenious acid injection formulations for intravenous selenium supplementation. The accused products included Fresenius Kabi’s selenious acid injections at 600 mcg/10 mL, 60 mcg/mL, and 12 mcg/2 mL concentrations.
No. A dismissal without prejudice means there was no adjudication on the merits. Fresenius Kabi did not obtain a finding of non-infringement or invalidity of US11998565B2. American Regent retains the right to refile infringement claims, and Fresenius Kabi’s selenious acid products remain potentially subject to future enforcement under this patent.
The case resolved in 141 days, which is unusually fast for pharmaceutical patent litigation in the District of New Jersey, where cases often take years to reach trial. The public record does not disclose the reason for the rapid resolution, but early dismissals of this type are consistent with confidential commercial negotiations, licensing discussions, or a strategic decision to reassess the litigation posture — none of which are confirmed by the court record.
American Regent was represented by Gibbons PC and Sterne Kessler Goldstein & Fox, with attorneys Charles H. Chevalier, Christine A. Gaddis, and Dennies Varughese named on the docket. Fresenius Kabi was represented by Midlige Richter LLC, with attorney James S. Richter appearing for the defendant.
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