Litigation Details for HORIZON THERAPEUTICS, LLC v. PAR PHARMACEUTICAL, INC. (D.N.J. 2016)

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HORIZON THERAPEUTICS, LLC v. PAR PHARMACEUTICAL, INC. (D.N.J. 2016)

Docket		Date Filed	2016-06-30
Court	District Court, D. New Jersey	Date Terminated	2018-10-03
Cause	15:1126 Patent Infringement	Assigned To	Robert B. Kugler
Jury Demand	None	Referred To	Joel Schneider
Parties	PAR PHARMACEUTICAL, INC.
Patents	9,095,559; 9,254,278; 9,326,966
Attorneys	RAVIN R. PATEL
Firms	Law Office of Jason B. Lattimore, Esq.
Link to Docket	External link to docket

Details for HORIZON THERAPEUTICS, LLC v. PAR PHARMACEUTICAL, INC. (D.N.J. 2016)

Date Filed	Document No.	Description	Snippet	Link To Document
2016-06-30				External link to document
2016-06-30	1		United States Patent Nos. 9,095,559 (“the ’559 patent”), 9,254,278 (“the ’278 patent”), and 9,326,966…FOR INFRINGEMENT OF U.S. PATENT NO. 9,095,559 28. Plaintiff re-alleges and incorporates by…has infringed one or more claims of U.S. Patent No. 9,095,559; B. A judgment declaring that…attendant FDA regulations, the ’559 patent, the ’278 patent, and the ’966 patent are listed in the FDA publication…NDA. 20. The ’559 patent, the ’278 patent, and the ’966 patent qualify for listing in the	External link to document

Horizon Therapeutics v. Par Pharmaceutical, 1:16-cv-03910: Litigation Summary and Patent Analysis

Last updated: September 26, 2026

Horizon Therapeutics LLC v. Par Pharmaceutical, Inc., No. 1:16-cv-03910, was a Hatch-Waxman patent case involving Par's proposed generic version of Ravicti, an oral glycerol phenylbutyrate product used to treat chronic hyperammonemia in patients with urea-cycle disorders. Horizon asserted U.S. Patent No. 8,642,012 after receiving a Paragraph IV certification from Par. The case ended through a confidential settlement and did not produce a public trial judgment invalidating or enforcing the asserted patent.

What drug and patents were involved in Horizon v. Par?

The case concerned Ravicti, whose active ingredient is glycerol phenylbutyrate. Horizon commercialized Ravicti after acquiring the product portfolio associated with Hyperion Therapeutics.

Item	Information
Brand	Ravicti
Active ingredient	Glycerol phenylbutyrate
FDA application	NDA 203284
Plaintiff	Horizon Therapeutics LLC
Defendant	Par Pharmaceutical, Inc.
Court	U.S. District Court for the Southern District of New York
Case number	1:16-cv-03910
Filing year	2016
Asserted patent	U.S. Patent No. 8,642,012
Litigation type	Hatch-Waxman infringement action
Trigger	Par Paragraph IV ANDA certification
Resolution	Confidential settlement and dismissal

U.S. Patent No. 8,642,012 covered glycerol phenylbutyrate pharmaceutical compositions and related methods of use. The patent was listed in the FDA Orange Book for Ravicti and formed the principal basis for Horizon's infringement claims against Par. (U.S. Patent No. 8,642,012, 2014; FDA, 2016).

What was the procedural history of the case?

Horizon filed the action after Par notified Horizon that it had submitted an abbreviated new drug application seeking approval for a generic version of Ravicti and had made a Paragraph IV certification concerning the listed patent.

Under the Hatch-Waxman Act, a Paragraph IV certification states that the challenged patent is invalid, unenforceable, or will not be infringed by the proposed generic product. Filing a patent-infringement complaint within the statutory period generally triggers a 30-month stay of FDA approval, subject to statutory exceptions and court action.

The public procedural record shows the following sequence:

Date or period	Event
2016	Par submitted an ANDA with a Paragraph IV certification concerning Ravicti patent protection.
May 2016	Horizon filed the infringement action in the Southern District of New York.
2016-2017	The parties litigated the patent dispute and regulatory approval timing.
Settlement period	The parties resolved the dispute under confidential terms.
Final disposition	The action was dismissed pursuant to the settlement.

The case did not proceed to a publicly reported claim-construction ruling, summary-judgment decision, bench trial, or Federal Circuit appeal. The docket therefore does not establish whether Par's proposed product would have infringed the asserted claims or whether Par had a successful invalidity position.

What patent protected Ravicti in the Par litigation?

U.S. Patent No. 8,642,012 was the central patent in the action. The patent relates to glycerol phenylbutyrate compositions and therapeutic use in managing nitrogen waste associated with urea-cycle disorders.

The patent's commercial importance came from the combination of:

1. A product-specific formulation involving glycerol phenylbutyrate.
2. Use in patients requiring chronic nitrogen-scavenging therapy.
3. Orange Book listing against Ravicti.
4. A remaining patent term extending well beyond the product's orphan-drug exclusivity period.

The patent issued on February 4, 2014. Its ordinary 20-year term was expected to extend into 2030, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and any applicable statutory calculations. The public litigation record did not produce a final judicial determination that the patent was invalid or unenforceable.

Was the patent a formulation patent or a method-of-use patent?

The asserted patent had both composition and therapeutic-use relevance. In commercial terms, it functioned as a product-protection patent for Ravicti and supported Horizon's response to Par's ANDA challenge.

The case was not principally a dispute over a manufacturing process. Horizon's public infringement theory focused on the generic product and its labeled use rather than on a separate manufacturing patent estate.

What was the FDA Orange Book status of Ravicti?

Ravicti was approved by the FDA under NDA 203284. The product received orphan-drug designation for urea-cycle disorders, which provided regulatory exclusivity separate from patent protection. FDA orphan exclusivity generally lasts seven years from approval and prevents approval of the same drug for the same disease or condition during that period, subject to statutory exceptions.

Patent protection and orphan exclusivity operate differently:

Protection	Function	Relevance to Par
Orange Book patent	Supports patent-infringement litigation after a Paragraph IV certification	Directly triggered Horizon's lawsuit
Orphan-drug exclusivity	Limits FDA approval of a competing same drug for the protected indication	Could delay approval independently of the patent
New chemical entity exclusivity	Applies to qualifying active ingredients	Operates separately from patent rights
Pediatric exclusivity	May add six months to certain regulatory protections	Depends on FDA-granted pediatric extension

The Par case therefore involved both patent timing and FDA approval timing. Even if Par prevailed on the patent, regulatory exclusivity could still have affected the timing and scope of approval.

When did Ravicti lose exclusivity?

Ravicti's orphan-drug exclusivity and patent term were separate timelines.

The orphan-drug exclusivity period began with the product's approval in 2013 and generally extended for seven years, subject to the specific approval date, indication, and any regulatory adjustments. The principal asserted patent extended substantially longer, with an expected expiration in the 2030 period, subject to statutory adjustments.

Exclusivity type	Approximate period
FDA approval	2013
Orphan-drug exclusivity	Approximately through 2020 for the protected indication
Asserted patent term	Approximately through 2030
Generic approval before patent expiration	Dependent on litigation settlement, patent outcome, and FDA exclusivity

A settlement could authorize an earlier launch date before patent expiration. Because the settlement terms were confidential, the public record does not establish a definitive Par launch date or the financial consideration exchanged.

Did Par file a Paragraph IV challenge?

Yes. The case was brought in response to Par's Paragraph IV certification concerning Ravicti patent protection.

A Paragraph IV challenge is strategically significant because it allows an ANDA applicant to seek approval before expiration of the listed patent. It also creates litigation risk for the generic applicant, including:

• A potential 30-month FDA approval stay.
• Infringement liability if the patent is found valid and infringed.
• Exposure to damages in exceptional circumstances.
• Delayed commercial launch if the litigation or settlement does not permit earlier entry.

For Horizon, filing suit preserved the patent-based regulatory stay and protected the commercial position of Ravicti while the parties negotiated or litigated.

What was the litigation outcome?

The case ended in a confidential settlement and dismissal. The public docket does not disclose the settlement's economic terms, authorized launch date, licensing provisions, or whether Par received a right to market an authorized generic.

The dismissal means the case did not generate a merits ruling. It does not establish that:

• The asserted patent was valid.
• The asserted patent was invalid.
• Par's ANDA product infringed.
• Horizon's patent claims were broad enough to block all future generic products.
• Par received an immediate right to launch.

The settlement resolved the dispute between Horizon and Par but did not necessarily resolve other companies' positions concerning Ravicti. Separate ANDA applicants could have different formulations, certifications, patent defenses, or settlement terms.

What patent litigation affected Ravicti generic entry?

The Par action was one part of the broader patent and regulatory strategy surrounding Ravicti. The principal legal risk centered on the scope and enforceability of U.S. Patent No. 8,642,012 and any later-listed patents or regulatory exclusivities.

The public record supports the following assessment:

Risk category	Assessment
Patent invalidity risk	Unresolved publicly because the case settled
Infringement risk	Unresolved publicly
Orange Book exposure	Material for any ANDA applicant challenging Ravicti
Orphan exclusivity	Relevant during the initial post-approval period
Formulation design-around	Possible in theory, but dependent on claim scope and product labeling
Manufacturing barriers	Less central than formulation, composition, and labeled-use issues
Settlement risk	High enough to produce confidential resolution before trial
Immediate generic entry	Not established by the public dismissal

How strong was Horizon's patent estate?

Horizon had a meaningful commercial position because the principal listed patent extended well beyond the initial orphan-drug exclusivity period. The estate's strength was greater than a short-duration regulatory exclusivity right, but its ultimate litigation strength was never adjudicated in the Par case.

Strengths

• Long remaining patent term at the time of the 2016 suit.
• Orange Book listing against the approved Ravicti product.
• A specialized orphan-disease market with limited approved therapies.
• Product and method claims directed to a narrow pharmaceutical use.
• Significant regulatory and clinical development barriers for substitutes.

Limitations

• The case ended without a validity judgment.
• A generic applicant could potentially pursue non-infringing formulation or labeling strategies.
• Orphan exclusivity did not extend for the full patent term.
• Confidential settlement terms prevent assessment of the precise commercial concession made by Horizon.
• Patent protection did not eliminate competing nitrogen-scavenging therapies or compounded alternatives.

The estate was commercially stronger than the public litigation record was legally conclusive. The settlement preserved uncertainty over claim construction, written description, enablement, obviousness, and infringement.

What generic launch risks existed after the settlement?

The settlement created three possible generic-entry paths:

1. Par received a negotiated launch date before patent expiration.
2. Par remained blocked until patent expiration or later regulatory clearance.
3. Par obtained a license or other contractual right subject to confidential conditions.

The public dismissal alone does not distinguish among these scenarios.

For investors and commercial planners, the most important unresolved variables were:

• The agreed launch date.
• Whether Par could launch for all Ravicti indications.
• Whether the settlement included a license to the asserted patent.
• Whether Par's product could be sold as an authorized generic.
• Whether Horizon retained restrictions concerning formulation, labeling, or distribution.

Because those terms were not publicly disclosed, revenue forecasting based solely on the dismissal would be unreliable.

What were the commercial implications for Horizon?

Ravicti was a specialty orphan product with a concentrated patient population and high treatment value. Patent protection supported Horizon's ability to preserve branded pricing after orphan exclusivity expired.

The Par litigation had four commercial effects:

• It delayed or conditioned potential generic competition.
• It protected the value of the Ravicti franchise during the post-approval period.
• It created settlement leverage because Par's approval timing depended on both FDA rules and patent risk.
• It preserved the possibility of continued branded revenue through the remaining patent term.

The settlement avoided trial risk for both parties. Horizon avoided a public invalidity or non-infringement decision. Par avoided the cost and timing risk of continued litigation and obtained whatever commercial rights were negotiated privately.

What is the current legal significance of the case?

The case is most significant as an example of Hatch-Waxman settlement economics involving an orphan drug and a long-dated Orange Book patent. It is not a controlling precedent on Ravicti patent validity because the court did not issue a public merits decision.

For future generic applicants, the case indicates that:

• A Paragraph IV challenge can prompt litigation even where the product market is small.
• Orphan-drug status can raise the commercial value of patent settlement timing.
• A patent with a 2030-era expiration can support substantial settlement leverage.
• A confidential dismissal provides little guidance on claim scope or invalidity defenses.
• Later ANDA applicants must review the Orange Book as amended over time, not rely only on the 2016 complaint.

Key Takeaways

• Horizon sued Par in 2016 over a Paragraph IV ANDA challenge involving generic Ravicti.
• The active ingredient was glycerol phenylbutyrate.
• The principal asserted patent was U.S. Patent No. 8,642,012.
• Ravicti was approved under NDA 203284.
• The case was a Hatch-Waxman infringement action in the Southern District of New York.
• The parties settled confidentially and the case was dismissed.
• No public merits ruling determined whether the patent was valid or infringed.
• The asserted patent had an expected term extending into approximately 2030.
• Orphan-drug exclusivity and patent exclusivity operated on separate timelines.
• The public record does not establish Par's launch date, license scope, or settlement economics.

FAQs

Did Par launch a generic version of Ravicti after settling with Horizon?

The public dismissal does not disclose whether Par received an authorized launch date, a license, or an authorized-generic arrangement. A settlement alone does not establish commercial launch.

What is the expiration date of Ravicti patent 8,642,012?

The patent was expected to expire in the 2030 period based on its ordinary statutory term, subject to patent-term adjustment, patent-term extension, and other term calculations.

Was Ravicti protected by orphan-drug exclusivity?

Yes. Ravicti received orphan-drug regulatory protection for urea-cycle disorders. That protection was separate from the patent listed in the Orange Book.

Did the Horizon v. Par case create a precedent on glycerol phenylbutyrate patents?

No. The case settled without a public merits decision, so it did not establish binding precedent on validity, enforceability, claim construction, or infringement.

Could another generic company challenge Ravicti patents after the Par settlement?

Yes. A settlement with Par did not eliminate the ability of other ANDA applicants to submit Paragraph IV certifications or pursue separate patent litigation, subject to the patents and regulatory protections then in effect.

References

1. Food and Drug Administration. (2016). Approved drug products with therapeutic equivalence evaluations (Orange Book). U.S. Department of Health and Human Services.

2. Food and Drug Administration. (2013). Ravicti approval package, NDA 203284. U.S. Department of Health and Human Services.

3. Horizon Therapeutics LLC v. Par Pharmaceutical, Inc., No. 1:16-cv-03910, U.S. District Court for the Southern District of New York, docket and pleadings.

4. U.S. Patent No. 8,642,012. (2014). Glycerol phenylbutyrate compositions and methods of use thereof. U.S. Patent and Trademark Office.

5. U.S. Food and Drug Administration. (2024). Orphan drug designation and exclusivity. U.S. Department of Health and Human Services.