DCT

1:23-cv-00607

AbbVie Inc v. Prinston Pharmaceutical Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:23-cv-00607, D. Del., 06/02/2023
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendants Prinston Pharmaceutical and Solco Healthcare are incorporated in Delaware, and Defendant Zhejiang Huahai is a foreign entity that may be sued in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendants’ submission of an Abbreviated New Drug Application (ANDA) to market a generic version of the endometriosis drug ORILISSA® constitutes an act of infringement of a patent directed to specific compositions of the active ingredient, elagolix sodium.
  • Technical Context: The technology concerns pharmaceutical compositions and processes for producing high-purity elagolix sodium, a GnRH receptor antagonist used to treat pain associated with endometriosis by reducing estrogen levels.
  • Key Procedural History: This lawsuit is the third filed by AbbVie against Prinston concerning its ANDA for a generic version of ORILISSA®. The "First Suit," filed October 27, 2022, asserted three patents, and the "Second Suit," filed April 28, 2023, asserted two different patents. This action follows a third notice letter from Prinston, challenging the newly issued patent-in-suit. Defendants have filed a Paragraph IV certification, asserting that the patent-in-suit is invalid, unenforceable, and/or not infringed.

Case Timeline

Date Event
2018-07-23 '239 Patent Priority Date
2019-07-23 ORILISSA® (NDA No. 210450) FDA Approval Date
2022-09-13 Prinston's First Notice Letter (re: other patents)
2022-10-27 AbbVie files "First Suit" against Prinston
2023-01-03 '239 Patent Issue Date
2023-03-14 Prinston's Second Notice Letter (re: other patents)
2023-04-20 Prinston's Third Notice Letter (re: '239 patent)
2023-04-28 AbbVie files "Second Suit" against Prinston
2023-06-02 Complaint Filing Date (Current Action)

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 11,542,239 - "Elagolix Sodium Compositions and Processes"

  • Issued: January 3, 2023

The Invention Explained

  • Problem Addressed: The patent addresses the challenge of producing a commercially viable, highly pure form of the active drug substance elagolix sodium. Because the substance is generally amorphous, its purification can be more complex than for substances with established polymorphic forms, making it difficult to achieve a desirable low impurity profile that meets regulatory standards in a reproducible and cost-effective manner (’239 Patent, col. 2:47-62).
  • The Patented Solution: The invention provides a composition of elagolix sodium (referred to as Compound (I)) that is defined by its high purity and strictly limited impurity profile. The patent claims a composition comprising at least 97% elagolix sodium by weight, with specific ceilings on the amount of certain enumerated impurity compounds (’239 Patent, Abstract; col. 2:16-24). The specification also discloses processes and intermediates for achieving this level of purity, distinguishing the invention from prior methods of making the drug (’239 Patent, col. 13:1-12).
  • Technical Importance: This technology is important for ensuring that a mass-produced pharmaceutical product meets stringent safety and quality standards required by regulatory bodies like the U.S. FDA, particularly by controlling for potentially harmful or mutagenic impurities (’239 Patent, col. 2:47-52, col. 2:58-62).

Key Claims at a Glance

  • The complaint asserts infringement of "one or more claims" of the ’239 Patent (Compl. ¶2). The following analysis focuses on independent claim 1.
  • Independent Claim 1:
    • A composition comprising: Compound (I) [elagolix sodium]...
    • ...and one or more impurity selected from the group consisting of: [chemical structures for impurities (iii) and (vii)]...
    • ...wherein Compound (I) comprises at least 97 weight percent of the composition...
    • ...and wherein the one or more impurity is present in an amount that is greater than zero and equal to or less than 3 weight percent of the composition.
  • The complaint’s general allegation of infringing "one or more claims" implicitly reserves the right to assert other independent and dependent claims.

III. The Accused Instrumentality

Product Identification

The accused instrumentality is "Prinston's Generic Product," an elagolix sodium oral tablet (in 150 mg and 200 mg base dosage forms) for which Defendants seek FDA approval via Abbreviated New Drug Application (ANDA) No. 217296 (Compl. ¶1, ¶54). The act of infringement alleged is the submission of this ANDA under 35 U.S.C. § 271(e)(2)(A) (Compl. ¶2, ¶63).

Functionality and Market Context

Prinston's Generic Product is intended to be a generic version of AbbVie's ORILISSA® tablets (Compl. ¶1, ¶54). ORILISSA® is a prescription drug approved for managing pain associated with endometriosis (Compl. ¶6). The complaint alleges that Prinston has represented to the FDA that its generic product is "pharmaceutically and therapeutically equivalent" to ORILISSA® (Compl. ¶62).

  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint alleges that the act of submitting the ANDA infringes the ’239 Patent because the product described therein, if approved and marketed, would meet the limitations of the patent's claims (Compl. ¶63). The infringement theory is based on the allegation that Prinston's product is equivalent to ORILISSA®, which is asserted to be covered by the patent (Compl. ¶11, ¶62).

'239 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A composition comprising: Compound (I),... Prinston's Generic Product is alleged to contain elagolix sodium as its active pharmaceutical ingredient, making it therapeutically equivalent to ORILISSA®. ¶54, ¶62 col. 2:5-18
...and one or more impurity selected from a group consisting of: [impurities (iii) and (vii)]... The complaint does not provide sufficient detail for analysis of this element. The allegation is presumably based on the inference that a bioequivalent generic manufacturing process would result in the same impurity profile claimed in the patent. ¶62 col. 3:5-14; col. 3:28-40
...wherein Compound (I) comprises at least 97 weight percent of the composition... The complaint does not provide specific data but infers that to be therapeutically equivalent to ORILISSA®, Prinston's Generic Product must meet this purity level. ¶62 col. 92:40-43
...and wherein the one or more impurity is present in an amount that is greater than zero and equal to or less than 3 weight percent of the composition. The complaint does not provide specific data but infers that to be therapeutically equivalent to ORILISSA®, Prinston's Generic Product must meet these impurity limits. ¶62 col. 92:43-47

Identified Points of Contention

  • Factual Question: The central issue is factual: will the chemical composition of Prinston's Generic Product, as specified in its confidential ANDA, fall within the scope of the asserted claims? The complaint provides no direct evidence (e.g., test results) and relies on the legal fiction of infringement established by the ANDA filing itself. Discovery into the contents of the ANDA will be dispositive for the infringement analysis.
  • Validity Question: Prinston has certified to the FDA that the ’239 Patent is invalid and/or not infringed (Compl. ¶61). This indicates that a significant point of contention will be the patent’s validity, likely involving arguments that the claimed purity levels were anticipated or would have been obvious to achieve using prior art manufacturing techniques.

V. Key Claim Terms for Construction

  • The Term: "composition"

    • Context and Importance: This term's construction is important for defining the object of infringement. Practitioners may focus on this term because its scope determines whether the claims are directed only to the purified active pharmaceutical ingredient (API) or also to the final formulated drug product containing excipients.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The term "composition" is not explicitly limited in the claims and could be argued to encompass the final tablet.
      • Evidence for a Narrower Interpretation: The patent specification repeatedly refers to the invention in the context of the "active drug substance" and its purification process, distinguishing it from impurities and other components (’239 Patent, col. 2:14-15, col. 2:53-58). This suggests the claims are directed to the API itself.

  • The Term: "at least about 97 weight percent"

    • Context and Importance: The word "about" introduces ambiguity into the numerical purity limit, and its interpretation will be critical to determining literal infringement. A defendant whose product is, for example, 96.9% pure would argue non-infringement, while the patentee would argue it falls within the scope of "about 97."
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification frequently uses "about" in relation to numerical values and ranges, including "at least about 97 or 98 weight percent" (’239 Patent, col. 3:65-66), suggesting the inventors did not intend a strict numerical boundary.
      • Evidence for a Narrower Interpretation: The patent discloses highly specific impurity limits down to the parts-per-million (ppm) level and provides detailed analytical methods (e.g., HPLC) for their measurement, which may suggest an intent for precision that would support a narrow reading of "about" (’239 Patent, col. 22:17-22).

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement (Compl. ¶64). The inducement theory is based on Defendants' knowledge of the patent (evidenced by the notice letter) and the allegation that the proposed product label will instruct medical professionals and patients to use the generic product in a way that directly infringes (Compl. ¶65-67). The contributory infringement allegation is based on the assertion that the generic product is especially adapted for an infringing use and has no substantial non-infringing use (Compl. ¶70-71).
  • Willful Infringement: While the word "willful" is not used, the complaint lays the groundwork for an exceptional case finding and an award of attorney fees by alleging that Defendants had knowledge of the ’239 Patent at least as of the date of their April 20, 2023 notice letter (Compl. ¶56, ¶68; Prayer for Relief ¶G).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central question for the case will be one of evidentiary proof: Will discovery of Prinston's confidential ANDA data show that its proposed generic product meets the specific purity and impurity limitations of the asserted claims, or will it reveal a composition that falls outside the patent's scope?
  • A second core issue will be the validity of the claims: Can Prinston demonstrate with clear and convincing evidence that claiming a specific purity profile for a known compound (elagolix sodium) was obvious or anticipated by the prior art at the time of the invention?
  • The outcome may also turn on a question of claim construction: How will the court define the scope of the term "about" as it applies to the claimed purity thresholds, and will that definition be expansive enough to read on the precise specifications of Prinston's product?