Par Pharmaceutical vs. Long Grove: Vasopressin Patent Suit Dismissed
A pharmaceutical patent infringement suit filed by Par Pharmaceutical, Inc., Par Sterile Products, LLC, and Endo Par Innovation Company, LLC against Long Grove Pharmaceuticals, LLC concluded with a Stipulation of Dismissal Without Prejudice on July 25, 2024 — just 230 days after it was filed in the U.S. District Court for the District of Delaware. Presided over by Chief Judge Gregory B. Williams, the case centered on two issued U.S. patents covering vasopressin injection formulations and the defendant’s competing generic product.
For patent attorneys, IP professionals, and pharmaceutical R&D teams, this case offers a window into the litigation dynamics surrounding vasopressin drug patent protection — a commercially sensitive area given the high-stakes market for critical care vasopressors. The dismissal without prejudice leaves open the possibility of future action, making this case a live reference point for competitive intelligence and patent risk management in the parenteral drug space.
Case No.: 1:23-cv-01412 | Court: D. Del. | Closed: July 25, 2024
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📋 Case Summary
| Case Name | Par Pharmaceutical, Inc. v. Long Grove Pharmaceuticals, LLC |
| Case Number | 1:23-cv-01412 (D. Del.) |
| Court | U.S. District Court for the District of Delaware |
| Duration | Dec 2023 – Jul 2024 7 months |
| Outcome | Dismissed Without Prejudice |
| Patents at Issue | |
| Accused Products | Vasopressin Injection formulations (0.2 Unit/mL, 0.4 Unit/mL, 1.0 Unit/mL) |
Case Overview
The Parties
⚖️ Plaintiff
Affiliated entities within the Endo International corporate family, responsible for branded pharmaceutical products including VASOSTRICT® (vasopressin injection).
🛡️ Defendant
Pharmaceutical company pursuing regulatory approval for generic vasopressin injection products under NDA No. 204485.
The Patents at Issue
Two U.S. patents were asserted in this action, both covering vasopressin injection formulations and methods of treatment:
- • U.S. Patent No. 9,993,520 B2 (Application No. 15/688,334)
- • U.S. Patent No. 11,207,372 B2 (Application No. 16/291,796)
Both patents relate to the pharmaceutical composition and use of vasopressin, a critical care hormone used to raise blood pressure in patients with vasodilatory shock.
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The Verdict & Legal Analysis
Outcome
The case was terminated via a Stipulation of Dismissal Without Prejudice — meaning neither party obtained a judicial determination on the merits of infringement or patent validity. No damages were awarded, no injunctive relief was granted or denied by the court, and no claim construction order was issued based on available case data.
A dismissal without prejudice is legally significant: it does not bar the plaintiffs from re-filing the same claims against Long Grove Pharmaceuticals in the future, provided applicable statutes of limitations and procedural requirements are satisfied.
Key Legal Issues
The infringement action was predicated on Long Grove’s alleged infringement of U.S. Patent Nos. 9,993,520 and 11,207,372 through its vasopressin injection products. Given the NDA-referencing framework underlying the dispute, this case bears hallmarks of Hatch-Waxman Act litigation, where branded pharmaceutical manufacturers assert patents against generic applicants seeking approval based on existing NDAs.
Hatch-Waxman litigation frequently resolves through negotiated settlement or licensing arrangements before reaching trial, which is consistent with this case’s rapid dismissal timeline. The **230-day duration** is notably shorter than the typical pharmaceutical patent trial cycle, reinforcing the inference that settlement or licensing discussions drove the resolution — though the specific terms of any underlying agreement were not disclosed in the case record.
The assertion of both U.S. 9,993,520 and the later-issuing U.S. 11,207,372 demonstrates Par’s use of a continuation patent portfolio strategy to extend protection across the vasopressin formulation space, a common and effective tactic in pharmaceutical IP prosecution.
Freedom to Operate (FTO) Analysis for Vasopressin Formulations
This case highlights critical IP risks in generic pharmaceutical development. Choose your next step:
📋 Understand This Case’s Impact
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- View all related patents in this technology space
- See which companies are most active in vasopressin patents
- Understand claim construction patterns for pharmaceutical formulations
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High Risk Area
Vasopressin injection formulations
2 Patents Asserted
In vasopressin formulation space
FTO Clearance Critical
For generic drug development
✅ Key Takeaways
Dismissal without prejudice in Hatch-Waxman cases rarely signals a plaintiff’s defeat — often reflecting a negotiated settlement.
Search related case law →Continuation patent portfolios (e.g., ‘520 → ‘372) remain powerful enforcement and licensing tools in pharmaceutical litigation.
Explore precedents →Delaware District Court continues to be the preferred venue for complex pharmaceutical patent disputes due to its experienced judiciary.
View D. Del. litigation data →Frequently Asked Questions
Two U.S. patents were asserted: U.S. Patent No. 9,993,520 B2 (App. No. 15/688,334) and U.S. Patent No. 11,207,372 B2 (App. No. 16/291,796), both covering vasopressin injection formulations.
The case was terminated via a Stipulation of Dismissal Without Prejudice, indicating a mutual resolution between the parties without a court ruling on infringement or validity. Specific settlement terms were not disclosed.
The without-prejudice dismissal preserves plaintiffs’ litigation rights, meaning these patents may be asserted again against Long Grove or other generic competitors. Companies in the vasopressin space should monitor this patent family closely.
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References
- United States Patent and Trademark Office — Patent 9,993,520 B2
- United States Patent and Trademark Office — Patent 11,207,372 B2
- PACER Case Locator – D. Del. 1:23-cv-01412
- Delaware District Court IP Docket
- PatSnap — IP Intelligence for Pharmaceuticals
This article is for informational purposes only and does not constitute legal advice. All case information is drawn from publicly available court records. For platform capabilities, visit PatSnap.