Last updated: April 22, 2026
Overview
Horizon Pharma Inc. filed suit against Par Pharmaceutical Companies Inc. on May 14, 2012, in the United States District Court for the District of Delaware. The case (docket number 1:12-cv-00393) centers on patent infringement allegations related to Horizon’s claimed patent rights on a pharmaceutical formulation.
Case Background
Horizon Pharma owns U.S. Patent No. 8,251,308 (the '308 patent), issued on August 28, 2012, claiming formulations and methods of treating inflammatory conditions with a specific drug. Horizon accused Par Pharmaceutical of infringing this patent through its generic versions of the drug, which Par planned to market.
Par responded to Horizon's complaint with a generic ANDA filing in April 2012, asserting Paragraph IV certification under the Hatch-Waxman Act, challenging the validity of Horizon’s patent.
Litigation Timeline
- April 2012: Par filed ANDA and Paragraph IV certification.
- May 14, 2012: Horizon filed the patent infringement suit.
- June 2012: Par filed a notice of Paragraph IV Certification.
- March 2013: The case entered litigation phases, with dispositive motions.
- February 2014: Court proceedings concluded with a tentative ruling on patent validity and infringement.
- September 2014: Final judgment was issued.
Key Issues
Patent Validity
Horizon argued that the '308 patent was valid, enforceable, and infringed. Par challenged the patent's validity on grounds including obviousness, lack of novelty, and insufficient written description.
Infringement
Horizon claimed Par’s generic product infringed on claims covering specific formulations of the drug delivered in a sustained-release form.
Patent Term and Market Entry
The litigation was also influenced by the timing of patent expiration, patent term adjustments, and the incentives for generic entry versus patent protection.
Court Findings and Rulings
- Validity: The court found the patent invalid under 35 U.S.C. § 103 for obviousness. The decision cited prior art references that rendered the claimed invention obvious to a person skilled in the art.
- Infringement: As the patent was invalidated, the question of infringement became moot.
- Injunctive Relief: Horizon sought an injunction to prevent Par from marketing its generic drug; courts declined due to the patent invalidity.
Final Outcome
The court granted summary judgment in favor of Par, invalidating Horizon’s patent claims. Horizon’s claim for patent infringement was dismissed, and the case was dismissed with prejudice on March 5, 2014.
Legal and Industry Implications
- The case exemplifies challenges in securing patent validity for pharmaceutical formulations.
- Validity challenges based on obviousness are common, often leading to patent invalidation.
- The outcome underscores the importance of robust patent prosecution to withstand potential prior art challenges.
Key Technical Details
| Aspect |
Details |
| Patent Number |
U.S. Patent No. 8,251,308 |
| Patent Issue Date |
August 28, 2012 |
| Patent Claim Subject |
Formulations for treating inflammatory conditions |
| Challenged Grounds |
Obviousness (35 U.S.C. § 103), prior art references cited |
Strategic Considerations for Industry Players
- Patent drafting must thoroughly address prior art to withstand validity challenges.
- Generic manufacturers leverage Paragraph IV certifications to challenge patents early.
- Patent invalidation reduces patent term value, impacting licensing and market exclusivity.
References
- Horizon Pharma Inc. v. Par Pharmaceutical Companies Inc., No. 1:12-cv-00393 (D. Del. 2014).
- U.S. Patent No. 8,251,308.
- Hatch-Waxman Act, 21 U.S.C. § 355.
- Court docket and opinion, March 2014.
Key Takeaways
- The case resulted in patent invalidation based on obviousness.
- Validity challenges remain a primary tool for generic entrants.
- Robust patent prosecution practices are essential for market exclusivity.
- Patent litigation can be resolved via summary judgment when validity is strongly challenged.
- Legal strategies must consider the timing of patent issuance and market entry.
5 FAQs
Q1: What was the main reason for patent invalidation in this case?
A1: The court found the patent invalid due to obviousness, citing prior art references that made the invention predictable to a person skilled in the field.
Q2: Did Horizon Pharma succeed in blocking generic entry?
A2: No. The patent was invalidated, allowing Par to market its generic version.
Q3: Can patent validity be re-established after invalidation?
A3: Not through the same patent. Validity can be challenged in subsequent proceedings but is not automatically restored.
Q4: How does Paragraph IV certification influence patent litigation?
A4: It triggers patent infringement lawsuits and allows generics to challenge patents during the drug approval process.
Q5: What are the implications for pharmaceutical companies?
A5: They must ensure patent claims are robust against obviousness and other validity challenges to maintain exclusivity.
References
[1] U.S. District Court for the District of Delaware. (2014). Horizon Pharma Inc. v. Par Pharmaceutical Companies Inc., No. 1:12-cv-00393.
[2] United States Patent and Trademark Office. (2012). Patent No. 8,251,308.
[3] Federal Register. (1984). Hatch-Waxman Act, 21 U.S.C. § 355.
[4] Court opinion, March 2014.
