Horizon Therapeutics v. Teva: 14-Patent Glycerol Phenylbutyrate Dispute Dismissed Without Prejudice
Horizon Therapeutics U.S. Holding LLC and Horizon Therapeutics USA, Inc. filed a 14-patent infringement action against Teva Pharmaceutical Industries in Delaware’s District Court over glycerol phenylbutyrate oral liquid. The parties jointly stipulated to dismiss all claims, counterclaims, and defenses without prejudice in just 63 days — a resolution that leaves the door open for future litigation.
A 14-patent ANDA fight resolved in 63 days — with strings attached
On 5 April 2024, Horizon Therapeutics U.S. Holding LLC and Horizon Therapeutics USA, Inc. filed suit against Teva Pharmaceutical Industries, Ltd. in the United States District Court for the District of Delaware before Judge Gregory B. Williams. The complaint asserted infringement of 14 U.S. patents — spanning application numbers from US12/350111 through US16/128140 — all directed to glycerol phenylbutyrate oral liquid, a drug used in the management of urea cycle disorders.
The case closed on 7 June 2024, just 63 days after filing, when both sides jointly stipulated to dismiss all claims, counterclaims, and defenses in their entirety without prejudice pursuant to Federal Rule of Civil Procedure 41(a)(1)(A)(ii). A dismissal without prejudice means no court has adjudicated the merits: Horizon retains the right to refile the same claims, and Teva has not secured any finding that the asserted patents are invalid or not infringed.
The sub-90-day resolution is notable given the breadth of the assertion — 14 patents covering a single oral liquid product. The speed and the without-prejudice nature of the dismissal are consistent with an interim commercial arrangement, a licensing negotiation, or a decision to await a different procedural posture, though the public record does not disclose the underlying reason. What remains unclear is whether a 30-month stay under the Hatch-Waxman Act was triggered and whether any side agreement governs future launch timing for Teva’s proposed generic product.
Filing to Dismissed without Prejudice in 63 days
63 days — well below the median ANDA patent litigation timeline of 2–4 years
Dismissed without prejudice: what the stipulation means for both parties
Rule 41(a)(1)(A)(ii): joint stipulated dismissal, no merits ruling
Under Federal Rule of Civil Procedure 41(a)(1)(A)(ii), parties may voluntarily dismiss an action by filing a signed stipulation. Because dismissal is without prejudice, no court has decided whether any of the 14 asserted patents are valid or infringed. The slate is wiped clean procedurally, but all substantive rights are preserved. Horizon can refile; Teva holds no invalidity or non-infringement judgment.
No merits adjudicatedHorizon preserves all 14 patent claims for future enforcement
A without-prejudice dismissal is not a concession. Horizon retains every one of the 14 asserted patents in its enforceability posture — none has been invalidated, limited, or licensed away on the public record. Horizon can refile in Delaware or another venue if Teva’s ANDA activity resumes or if a new trigger arises. The breadth of the portfolio (14 patents across multiple application families) suggests a layered Hatch-Waxman strategy that likely continues outside the courtroom.
Patents fully preservedTeva secures no invalidity finding — future launch risk remains
Teva exits this proceeding without a single patent invalidated or a non-infringement ruling in its favour. If Teva intends to launch a generic glycerol phenylbutyrate oral liquid, the full weight of Horizon’s 14-patent portfolio still stands as a potential barrier. The dismissal without prejudice may reflect a negotiated standstill or licensing discussion, but Teva’s commercial path to market is not cleared by this outcome alone.
No clearance obtainedHatch-Waxman uncertainty persists around glycerol phenylbutyrate generics
For competing manufacturers and market analysts, the without-prejudice dismissal preserves Horizon’s ability to assert a dense 14-patent thicket against any future ANDA filer for glycerol phenylbutyrate oral liquid. The absence of any merits ruling means the patent landscape around this product remains fully intact. Companies planning generic entry should treat all 14 asserted patents as live enforcement risks until a court, the USPTO, or a licensing agreement changes the calculus.
Patent thicket intactFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Horizon Therapeutics U.S. Holding LLC | Company | Rare-disease pharmaceutical company — holder of US9561197B2 and 13 related glycerol phenylbutyrate patentsSearch in Eureka ↗ |
| Co-Plaintiff | Horizon Therapeutics USA, Inc. | Company | Search in Eureka ↗ |
| Defendant | Teva Pharmaceutical Industries, Ltd. | Company | Teva Pharmaceutical Industries, Ltd. — global generic drug manufacturer seeking regulatory approval for glycerol phenylbutyrate oral liquidSearch in Eureka ↗ |
| Plaintiff counsel | James L. Higgins | Attorney | Counsel for Horizon Therapeutics U.S. Holding LLCSearch in Eureka ↗ |
| Plaintiff counsel | Melanie K. Sharp | Attorney | Counsel for Horizon Therapeutics U.S. Holding LLCSearch in Eureka ↗ |
| Plaintiff counsel | Stephanie Vangellow | Attorney | Counsel for Horizon Therapeutics U.S. Holding LLCSearch in Eureka ↗ |
| Plaintiff counsel | Taylor E. Hallowell | Attorney | Counsel for Horizon Therapeutics U.S. Holding LLCSearch in Eureka ↗ |
| Plaintiff law firm | Young Conaway Stargatt & Taylor, LLP | Law Firm | Representing Horizon Therapeutics U.S. Holding LLCSearch in Eureka ↗ |
| Defendant counsel | Karen E. Keller | Attorney | Counsel for Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Defendant law firm | Shaw Keller LLP | Law Firm | Representing Teva Pharmaceutical Industries, Ltd.Search in Eureka ↗ |
| Presiding judge | Judge Gregory B. Williams | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulation invokes Rule 41(a)(1)(A)(ii), the joint dismissal mechanism, and explicitly extends the dismissal to ‘all claims, counterclaims and defenses in their entirety.’ The without-prejudice qualifier is dispositive: no finding on validity, infringement, or enforceability has been made. For Horizon, every asserted patent retains its legal presumption of validity. For Teva, no affirmative defence has been adjudicated. The case is closed on the docket but legally unresolved on the merits.
US9561197B2 and 13 related patents — glycerol phenylbutyrate oral liquid formulations
The 14 asserted patents — anchored by US9561197B2 (application US13/610580) and extending through US10668040B2 (application US16/128140) — cover glycerol phenylbutyrate oral liquid, a nitrogen-scavenging agent indicated for urea cycle disorders (UCDs). The application filing dates span from roughly 2009 through 2018, indicating a sustained prosecution strategy built on continuation and related filings designed to extend coverage as the product and its clinical use evolved. The patents collectively protect formulation composition, dosing methods, and delivery characteristics of the oral liquid product.
For the rare-disease pharmaceutical sector, a 14-patent portfolio around a single oral liquid product represents a formidable exclusivity barrier. Glycerol phenylbutyrate (marketed as Ravicti by Horizon) is the primary nitrogen-scavenging therapy for UCD patients, a small but commercially significant population. The breadth and depth of the patent estate — spanning multiple continuation families across a decade of prosecution — is consistent with a deliberate strategy to deter generic entry and maximise the commercial exclusivity window, making this portfolio a high-priority monitoring target for any ANDA filer or competitor in the rare metabolic disease space.
Should your team run an FTO against Horizon’s glycerol phenylbutyrate patent estate?
Any company developing, formulating, or seeking regulatory approval for a glycerol phenylbutyrate oral liquid product should treat this 14-patent portfolio as a live enforcement risk. The without-prejudice dismissal means none of these patents has been invalidated or narrowed. ANDA filers, 505(b)(2) applicants, and international generic manufacturers planning U.S. entry for any nitrogen-scavenging oral liquid product in the UCD space should conduct a thorough freedom-to-operate analysis across all 14 patent numbers and their prosecution histories before advancing development.
PatSnap Eureka’s FTO Search Agent enables R&D and regulatory teams to map all 14 asserted patents against a proposed product’s composition and method of use, flagging claim-level overlap and identifying file-wrapper estoppel arguments. Eureka’s prosecution history viewer and continuation family tracker can identify any pending continuations that may expand the enforcement footprint further — critical intelligence before committing capital to a generic glycerol phenylbutyrate programme.
Run a freedom-to-operate analysis on US9561197B2 to assess your product’s exposure
Run FTO in Eureka →Similar Hatch-Waxman pharmaceutical patent cases in Delaware District Court
Explore comparable ANDA-triggered patent infringement actions involving oral liquid drug formulations and multi-patent portfolios litigated in the Delaware District Court.
What this case signals for the Hatch-Waxman pharmaceutical IP landscape
A 14-patent assertion resolved in 63 days without prejudice is rarely a clean exit — it is typically a pause in a larger strategic contest.
Dense patent portfolios give branded pharma repeated-bite-at-the-apple leverage
Horizon’s 14-patent assertion across multiple application families reflects a classic Hatch-Waxman layering strategy. Even if a generic challenger invalidates one or two patents, the remaining claims sustain enforcement. IP teams at generic manufacturers should map every patent family before filing an ANDA, not just the lead patent.
Without-prejudice dismissals in ANDA cases rarely signal a clean resolution
In Hatch-Waxman litigation, early stipulated dismissals without prejudice frequently accompany confidential consent judgments, licensing term sheets, or agreed launch-date restrictions. The 63-day window is too short for substantive litigation; something was likely agreed off-record. Monitoring Teva’s ANDA approval status and any subsequent Horizon refiling will be critical to understanding the real outcome.
Horizon v Teva — key questions answered
Horizon asserted 14 U.S. patents covering glycerol phenylbutyrate oral liquid, including US9561197B2, US10183006B2, US9326966B2, US9999608B2, US9254278B2, US10045958B1, US10183005B2, US8642012B2, US10668040B2, US9962359B2, US10045959B1, US10183004B2, US10183002B2, and US10183003B2. All were asserted in the Delaware District Court in an infringement action related to Teva’s ANDA filing for glycerol phenylbutyrate oral liquid.
The parties filed a joint stipulation under Federal Rule of Civil Procedure 41(a)(1)(A)(ii) to dismiss all claims, counterclaims, and defenses without prejudice. The public record does not disclose the underlying reason. The short timeline and without-prejudice nature are consistent with confidential negotiations, a licensing arrangement, or a strategic decision to pause litigation — but no merits ruling was reached.
No. A dismissal without prejudice carries no adjudication on the merits. None of the 14 asserted patents have been found invalid, unenforceable, or not infringed as a result of this dismissal. All patents retain their statutory presumption of validity. Horizon retains the right to refile infringement claims against Teva or other generic manufacturers.
Yes. Because the dismissal was entered without prejudice, Horizon is not barred from refiling the same or substantially similar claims against Teva in a future action. However, a second voluntary dismissal without prejudice could, in some circumstances, operate as an adjudication on the merits under Rule 41(a)(1)(B), depending on the history of prior dismissals between the same parties.
Glycerol phenylbutyrate is a nitrogen-scavenging agent used to manage hyperammonemia in patients with urea cycle disorders, marketed as Ravicti by Horizon Therapeutics. As a rare-disease drug with limited patient populations and premium pricing, the product supports a dense patent portfolio. Generic entry would significantly reduce revenue, giving branded manufacturers strong economic incentive to assert broad, multi-patent estates against ANDA filers.
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