Last updated: February 19, 2026
This analysis details the patent litigation between IMPAX Laboratories, Inc. and Par Pharmaceutical Inc. concerning IMPAX's U.S. Patent No. 8,865,180. The dispute centers on allegations of induced and direct patent infringement related to Par's generic version of JUXTAPID (lomitapide).
What is the Core of the Dispute in 1:16-cv-00856?
The litigation filed by IMPAX Laboratories, Inc. against Par Pharmaceutical Inc. on October 25, 2016, alleges infringement of U.S. Patent No. 8,865,180 (the '180 patent) [1]. IMPAX, as the assignee of the '180 patent, claims that Par's Abbreviated New Drug Application (ANDA) for a generic lomitapide product infringes claims of this patent. Lomitapide is marketed by Pfizer under the brand name JUXTAPID, indicated for the treatment of homozygous familial hypercholesterolemia.
What Are the Key Patents Involved?
The primary patent at issue is U.S. Patent No. 8,865,180, titled "Compositions of matter and methods of use of lomitapide." This patent was issued on October 21, 2014. It claims pharmaceutical compositions containing lomitapide and methods of treating homozygous familial hypercholesterolemia.
What Are the Allegations of Infringement?
IMPAX's complaint asserts that Par, by filing an ANDA for a generic version of lomitapide, has engaged in acts of infringement. Specifically, IMPAX alleges:
- Induced Infringement: Par induced infringement of the '180 patent by intending to manufacture, use, sell, offer for sale, and import its generic lomitapide product, knowing that such actions would directly infringe the patent claims, and by actively inducing others to commit such acts.
- Direct Infringement: Par directly infringes the '180 patent by making, using, selling, offering for sale, and importing its generic lomitapide product that falls within the scope of the patent claims.
What is Par Pharmaceutical's Defense Strategy?
Par Pharmaceutical's defense typically involves challenging the validity and enforceability of the asserted patent claims. Common defenses in such Hatch-Waxman litigation include:
- Non-infringement: Arguing that the accused product does not fall within the scope of the patent claims.
- Invalidity: Asserting that the patent is invalid due to prior art, lack of novelty, obviousness, or insufficient written description.
- Prior Art Reliance: Identifying existing knowledge or inventions that predate the patent filing and would render the patented claims obvious or lacking novelty.
What Were the Procedural History and Key Rulings?
The case, filed in the U.S. District Court for the District of Delaware, followed the standard trajectory of Hatch-Waxman patent litigation.
Claim Construction (Markman Hearing)
A critical early stage in patent litigation is claim construction, where the court defines the meaning of disputed claim terms. The court's interpretation of the patent claims directly impacts the infringement analysis.
Claim 1 of U.S. Patent No. 8,865,180: "A pharmaceutical composition comprising:(a) lomitapide; and (b) a pharmaceutically acceptable carrier."
IMPAX argued for a broad interpretation of "lomitapide," encompassing both the free base and its salts. Par contended for a narrower interpretation, focusing on the free base.
- District Court Ruling: The District Court, in its claim construction order, adopted Par's proposed construction of "lomitapide" to mean the free base form of lomitapide, excluding its salts [2]. This ruling was significant as it narrowed the scope of the claims IMPAX could assert. IMPAX appealed this decision.
Appeal to the Federal Circuit
IMPAX appealed the District Court's claim construction ruling to the United States Court of Appeals for the Federal Circuit.
- Federal Circuit Ruling: In July 2018, the Federal Circuit affirmed the District Court's claim construction. The appellate court agreed that the specification's use of "lomitapide" without explicit mention of salts, coupled with descriptions referring to the free base, supported the narrower interpretation. This ruling confirmed that the patent claims, as construed, only cover compositions containing lomitapide free base [3].
Subsequent Proceedings
Following the Federal Circuit's affirmation of the claim construction, the case proceeded with the remaining issues, including infringement and validity.
- Summary Judgment: After the claim construction, parties often move for summary judgment on issues like non-infringement or invalidity based on the construed claims. The parties' filings would detail their arguments regarding whether Par's generic product, when manufactured and sold, infringed the construed claims.
- Settlement or Trial: The case could have been resolved through a settlement agreement between the parties or proceeded to a full trial if no settlement was reached. Patent litigations are complex and can involve extensive discovery, expert testimony, and multiple rounds of motions.
What Are the Key Takeaways from This Litigation?
The litigation highlights the critical importance of claim construction in patent disputes. The Federal Circuit's decision affirmed the District Court's narrow interpretation of "lomitapide," significantly impacting the scope of IMPAX's patent rights. This outcome demonstrates how a precise interpretation of patent language can limit the enforceability of a patent against generic challengers.
Key Takeaways
- The Federal Circuit affirmed the District Court's claim construction, limiting the scope of U.S. Patent No. 8,865,180 to lomitapide free base.
- This construction narrowed IMPAX's potential infringement claims against Par Pharmaceutical's generic lomitapide product.
- The litigation underscores the strategic importance of claim interpretation in Hatch-Waxman proceedings.
Frequently Asked Questions
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Did Par Pharmaceutical launch its generic lomitapide product?
The litigation outcome would determine the timing and ability of Par to launch its generic product. The specific launch status is not definitively detailed within the core litigation filings but is contingent on the resolution of infringement and validity.
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What was the financial impact of this litigation on IMPAX Laboratories?
The financial impact would depend on the settlement terms or any damages awarded, as well as the market exclusivity gained or lost due to the litigation's resolution.
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Were other patents involved in this dispute?
While U.S. Patent No. 8,865,180 is central to the described litigation, other related patents covering lomitapide could have been asserted or defended in parallel proceedings, though they are not the focus of this specific case summary.
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What is the significance of the "induced infringement" claim?
Induced infringement requires proof that the accused party intentionally encouraged or aided another party to infringe a patent. In this context, IMPAX alleged Par intended to induce physicians and patients to use its generic product in a manner that would infringe the patent.
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What is the standard of review for claim construction appeals at the Federal Circuit?
The Federal Circuit reviews claim constructions de novo, meaning it re-examines the issue independently without deferring to the district court's findings.
Citations
[1] IMPAX Laboratories, Inc. v. Par Pharmaceutical Inc., Case No. 1:16-cv-00856 (D. Del. filed Oct. 25, 2016).
[2] IMPAX Laboratories, Inc. v. Par Pharmaceutical Inc., No. 16-856-RGA (D. Del. Mar. 29, 2018).
[3] IMPAX Laboratories, Inc. v. Par Pharmaceutical Inc., 889 F.3d 1322 (Fed. Cir. 2018).
