Background and Context
Horizon Therapeutics, LLC, a biopharmaceutical company focused on developing and commercializing innovative medicines, has been involved in several legal battles with generic pharmaceutical companies, including Par Pharmaceutical, Inc. One of the notable cases is the litigation surrounding the patent infringement of Horizon's drug DUEXIS® and other patents related to nitrogen scavenging drugs.
DUEXIS® Patent Infringement Lawsuit
In 2012, Horizon Pharma, Inc. (now known as Horizon Therapeutics, LLC) filed a patent infringement lawsuit against Par Pharmaceutical, Inc. in the United States District Court for the District of Delaware. The lawsuit was in response to Par Pharmaceutical's filing of an Abbreviated New Drug Application (ANDA) with the FDA to market a generic version of DUEXIS® tablets. Horizon claimed that Par's generic version would infringe on US patent 8,067,033, which is listed in the FDA's Orange Book and was set to expire on July 18, 2026[1].
Paragraph IV Patent Certification
Par Pharmaceutical had provided Horizon with a Paragraph IV Patent Certification, asserting that its generic version of DUEXIS® would not infringe on the patent or that the patent was invalid or unenforceable. Horizon initiated the lawsuit within the required 45-day period to automatically stay the FDA's approval of Par's ANDA for 30 months or until a district court decision, whichever came first[1].
Inter Partes Review (IPR) of Nitrogen Scavenging Drug Patents
In a separate but related matter, Par Pharmaceutical initiated an inter partes review (IPR) against Horizon Therapeutics' patent related to the treatment of nitrogen retention states, particularly urea cycle disorders (UCDs). The patent in question, US 8,642,012 B2, involves methods for administering compounds that assist in the elimination of waste nitrogen from the body. The Patent Trial and Appeal Board (PTAB) found a reasonable likelihood that Par Pharmaceutical would prevail on its challenges to claims 1-12 of the patent and instituted the IPR[4].
Real Parties-in-Interest
During the IPR proceedings, there was a dispute over whether Par Pharmaceutical Companies, Inc., the parent company of Par Pharmaceutical, Inc., should be identified as a real party-in-interest. The PTAB ultimately decided that Par Pharmaceutical Companies, Inc. did not have control over the proceeding and thus did not need to be identified as a real party-in-interest[4].
Claim Construction and Merits
The PTAB interpreted the terms of the patent according to their broadest reasonable interpretation and found that Par Pharmaceutical had presented adequately supported contentions regarding the merits of its challenges. However, the PTAB declined to institute trial on certain grounds that were deemed duplicative[4].
Legal Implications and Strategies
The litigation and IPR proceedings highlight several key legal strategies and implications:
Patent Infringement Litigation
- Horizon Therapeutics' swift action in filing a patent infringement lawsuit against Par Pharmaceutical demonstrates the importance of protecting intellectual property rights. By initiating the lawsuit within the required timeframe, Horizon was able to automatically stay the FDA's approval of Par's ANDA, potentially delaying the entry of a generic competitor into the market[1].
Inter Partes Review
- Par Pharmaceutical's decision to initiate an IPR against Horizon Therapeutics' patent shows the use of IPR as a strategic tool to challenge the validity of patents. The PTAB's decision to institute the IPR based on Par's contentions underscores the potential for generic companies to use IPR as a means to clear the path for their generic products[4].
Industry Impact
These legal battles have significant implications for the pharmaceutical industry:
Generic Competition
- The ability of generic companies like Par Pharmaceutical to challenge patents through IPR and ANDA filings can accelerate the entry of generic drugs into the market, potentially reducing costs for consumers and increasing competition.
Innovation and R&D
- The protection of patents, as seen in Horizon Therapeutics' actions, is crucial for biopharmaceutical companies to recoup their investment in research and development. Strong patent protection can incentivize innovation by ensuring that companies can benefit financially from their discoveries.
Key Takeaways
- Patent Protection: Biopharmaceutical companies must be vigilant in protecting their patents to maintain market exclusivity and recoup R&D investments.
- Generic Competition: Generic companies can use IPR and ANDA filings as strategic tools to challenge patents and expedite market entry.
- Legal Strategies: Timely and strategic legal actions, such as filing lawsuits and initiating IPR, are critical in pharmaceutical patent disputes.
- Regulatory Environment: Understanding the regulatory framework, including the role of the FDA and PTAB, is essential for navigating patent disputes in the pharmaceutical industry.
FAQs
What is the significance of the Paragraph IV Patent Certification in the context of ANDA filings?
A Paragraph IV Patent Certification is a statement by the generic drug applicant that the patent listed in the FDA's Orange Book is invalid, unenforceable, or will not be infringed by the generic drug. This certification can trigger a patent infringement lawsuit by the brand-name drug manufacturer.
How does the inter partes review (IPR) process affect patent disputes in the pharmaceutical industry?
The IPR process allows parties to challenge the validity of patents before the PTAB. This can be a faster and less expensive alternative to district court litigation, and it can significantly impact the validity of patents, thereby affecting the market entry of generic drugs.
What are the implications of the PTAB's decision on real parties-in-interest in IPR proceedings?
The PTAB's decision on real parties-in-interest determines which entities have control over the IPR proceeding. This is crucial because it affects who must be identified and potentially held liable in the proceedings.
How do patent infringement lawsuits and IPR proceedings impact the pharmaceutical industry's innovation and competition?
Patent infringement lawsuits and IPR proceedings can influence the balance between innovation and competition. Strong patent protection can incentivize innovation, while successful challenges to patents can accelerate generic competition and reduce drug prices.
What role does the FDA play in the approval of generic drugs in the context of patent disputes?
The FDA's approval process for generic drugs can be stayed if a patent infringement lawsuit is filed within 45 days of the generic applicant's Paragraph IV certification. This stay can delay the FDA's approval of the generic drug until the litigation is resolved or for up to 30 months.
Cited Sources:
- Horizon Pharma, Inc. Files Patent Infringement Lawsuit Against Par Pharmaceutical, Inc. - Biospace.
- Par Pharm., Inc. v. Horizon Therapeutics, LLC - Casetext.
- Methods of therapeutic monitoring of nitrogen scavenging drugs - Google Patents.
- Par Pharmaceutical v. Horizon Therapeutics: Institution of Inter Partes Review - National Law Review.
