DCT

1:25-cv-00343

Sumitomo Pharma Switzerland GmbH v. Aizant Drug Research Solutions Pvt Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00343, D. Del., 03/19/2025
  • Venue Allegations: Venue is alleged to be proper on the basis that Defendant is a foreign corporation and may be sued in any judicial district.
  • Core Dispute: Plaintiffs allege that Defendant’s submission of an Abbreviated New Drug Application (ANDA) to the FDA for a generic version of Plaintiffs’ prostate cancer drug Orgovyx® (relugolix) constitutes an act of patent infringement.
  • Technical Context: The technology relates to compositions and methods of use for relugolix, a nonpeptide gonadotropin-releasing hormone (GnRH) receptor antagonist used for the treatment of advanced prostate cancer.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendant's notification to Plaintiffs, via a Paragraph IV certification letter, of its filing of ANDA No. 220197. In its certification, Defendant asserted that the patents-in-suit are invalid or will not be infringed by its proposed generic product.

Case Timeline

Date Event
2012-09-28 Earliest Priority Date for U.S. Patent No. 11,795,178
2016-09-30 Earliest Priority Date for U.S. Patent Nos. 12,097,198 & 12,144,809
2020-12-18 FDA approves Orgovyx® (relugolix) New Drug Application
2023-10-24 U.S. Patent No. 11,795,178 Issues
2024-09-24 U.S. Patent No. 12,097,198 Issues
2024-11-19 U.S. Patent No. 12,144,809 Issues
2025-02-05 Aizant sends Paragraph IV Notice Letter to Plaintiffs
2025-03-19 Complaint for Patent Infringement Filed

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

U.S. Patent No. 11,795,178 - "Compositions of Thienopyrimidine Derivatives"

  • Patent Identification: U.S. Patent No. 11,795,178, "Compositions of Thienopyrimidine Derivatives," issued October 24, 2023.
  • The Invention Explained:
    • Problem Addressed: The patent background section describes a general demand for a safe and efficient production method for thienopyrimidine derivatives (the chemical class of relugolix) that results in a high-quality (e.g., high purity) and high-yield product for use as a GnRH antagonist (’178 Patent, col. 2:9-15).
    • The Patented Solution: The invention provides methods for producing specific crystalline forms of a relugolix compound and compositions containing the active ingredient with very low levels of specific impurities (’178 Patent, col. 2:16-35, col. 12:42-50). The claims are directed not to the active ingredient itself, but to a mixture comprising the active ingredient and a specified related substance below a certain threshold, defining a particular purity profile for the final drug product.
    • Technical Importance: For pharmaceutical products, controlling the purity profile and the amount of related substances is critical for ensuring safety, efficacy, and stability, and is a key focus of regulatory review.
  • Key Claims at a Glance:
    • The complaint asserts infringement of at least claims 1-6, 9-11, 14-19, and 25-29 (Compl. ¶33). Independent claim 1 is representative.
    • Independent Claim 1:
      • A mixture comprising 1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea, or a salt or solvate thereof,
      • and 6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione,
      • wherein the 6-(4-aminophenyl)...dione is present in an amount of about 0.25% or less of the mixture.
    • The complaint states infringement of at least the listed claims, which include multiple independent and dependent claims (Compl. ¶33).

U.S. Patent No. 12,097,198 - "Treatment of Prostate Cancer"

  • Patent Identification: U.S. Patent No. 12,097,198, "Treatment of Prostate Cancer," issued September 24, 2024.
  • The Invention Explained:
    • Problem Addressed: The patent addresses the treatment of androgen-dependent cancers, like prostate cancer, where therapies aim to reduce serum testosterone levels (’198 Patent, col. 1:40-62). It notes that traditional GnRH agonists cause an initial testosterone surge or "clinical flare," which can worsen symptoms, and that such agonists are not orally available (’198 Patent, col. 2:4-21).
    • The Patented Solution: The invention provides a method for treating prostate cancer by administering a specific oral dosing regimen of relugolix (referred to as Compound 1). This regimen involves an initial, higher "loading dose" followed by a lower daily "maintenance dose," designed to rapidly suppress testosterone without the clinical flare associated with agonists (’198 Patent, Abstract; col. 2:32-3:3).
    • Technical Importance: An oral, non-peptide GnRH antagonist with a rapid onset of action and without a clinical flare offers a more convenient and potentially safer alternative to injectable depot GnRH agonists for androgen deprivation therapy.
  • Key Claims at a Glance:
    • The complaint asserts infringement of at least claims 1-2, 4-6, and 10-12 (Compl. ¶43). Independent claim 1 is representative.
    • Independent Claim 1:
      • A method of treating prostate cancer in a subject in need thereof,
      • comprising orally administering to the subject a loading dose of about 360 mg of [relugolix]... on day 1 of treatment,
      • and thereafter orally administering to the subject a maintenance dose of about 120 mg of [relugolix]... once daily.
    • The complaint asserts infringement of at least the listed claims, which include multiple independent and dependent claims (Compl. ¶43).

U.S. Patent No. 12,144,809 - "Treatment of Prostate Cancer"

  • Multi-Patent Capsule
    • Patent Identification: U.S. Patent No. 12,144,809, "Treatment of Prostate Cancer," issued November 19, 2024 (Compl. ¶22).
    • Technology Synopsis: Based on its title and shared expiration date with the ’198 Patent, the ’809 Patent relates to methods of using relugolix for treating prostate cancer. Such patents often claim different dosing regimens, patient populations, or specific therapeutic outcomes achieved by administering the drug.
    • Asserted Claims: Claims 1, 3, 5, 9, 12, 19, and 23-29 (Compl. ¶53).
    • Accused Features: The accused feature is the proposed method of use for Defendant's ANDA product, which Plaintiffs allege will be described in the product's labeling and will instruct medical professionals and patients to administer the generic drug in a manner that infringes the patent (Compl. ¶56).

III. The Accused Instrumentality

  • Product Identification: Aizant's ANDA Product, a 120 mg tablet of relugolix, submitted to the FDA for approval under ANDA No. 220197 (Compl. ¶1, ¶25).
  • Functionality and Market Context: The complaint alleges that the ANDA Product is a generic version of Orgovyx®, a branded drug approved for treating adult patients with advanced prostate cancer (Compl. ¶1, ¶18). By submitting the ANDA, Aizant has represented to the FDA that its product contains the same active ingredient (relugolix), has the same dosage form and strength (120 mg tablet), and is bioequivalent to Orgovyx® (Compl. ¶26). This regulatory framework implies that the ANDA product is intended to be used interchangeably with the branded drug for its approved indication.

IV. Analysis of Infringement Allegations

U.S. Patent No. 11,795,178 Infringement Allegations

The complaint alleges that the submission of the Aizant ANDA was an act of infringement under 35 U.S.C. § 271(e)(2)(A) because the ANDA Product is a composition that will fall within the scope of at least claim 1 (Compl. ¶33).

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A mixture comprising 1-{4-[1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]pyrimidin-6-yl]phenyl}-3-methoxyurea, or a salt or solvate thereof... Aizant’s ANDA Product is alleged to be a mixture containing the active pharmaceutical ingredient relugolix, which is the specified chemical compound. ¶33 col. 12:42-50
...and 6-(4-aminophenyl)-1-(2,6-difluorobenzyl)-5-dimethylaminomethyl-3-(6-methoxypyridazin-3-yl)thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione... The ANDA Product is alleged to contain this specified related substance as a component of the mixture. ¶33 col. 11:45-51
...wherein the 6-(4-aminophenyl)...dione is present in an amount of about 0.25% or less of the mixture. The ANDA Product is alleged to have a purity profile wherein the specified related substance is present at a concentration of about 0.25% or less. ¶33 col. 32:1-4
  • Identified Points of Contention:
    • Evidentiary Question: A central question will be factual and evidentiary: does the specific formulation described in Aizant's confidential ANDA submission actually contain the "6-(4-aminophenyl)...dione" related substance at a level of "about 0.25% or less"? The dispute may center on the chemical analysis of Aizant's proposed commercial product.
    • Scope Questions: The interpretation of "a mixture" may be contested. Aizant might argue its final drug product, which includes excipients, is not merely the claimed two-component mixture, raising a question of whether the claim reads on the ANDA product as a whole.

U.S. Patent No. 12,097,198 Infringement Allegations

The infringement theory is that Aizant will induce infringement by healthcare providers and patients under 35 U.S.C. § 271(b) because its proposed product labeling will instruct them to administer the generic drug according to the patented method (Compl. ¶46).

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating prostate cancer in a subject in need thereof... Aizant's proposed product label will allegedly instruct the use of its generic relugolix tablets for the treatment of prostate cancer, the FDA-approved indication for Orgovyx®. ¶46 col. 1:40-43
...comprising orally administering to the subject a loading dose of about 360 mg of [relugolix]... on day 1 of treatment... The proposed label will allegedly instruct physicians and patients to begin treatment with a loading dose of approximately 360 mg on the first day. ¶43, ¶46 col. 63:1-4
...and thereafter orally administering to the subject a maintenance dose of about 120 mg of [relugolix]... once daily. The proposed label will allegedly instruct physicians and patients to continue treatment with a daily maintenance dose of approximately 120 mg. ¶43, ¶46 col. 63:4-11
  • Identified Points of Contention:
    • Label Scope Question: The primary question is whether the final, FDA-approved label for Aizant's product will contain instructions that direct or encourage the specific loading dose/maintenance dose regimen of claim 1. In ANDA litigation, if the proposed label carves out the patented method, infringement may be avoided; if it mirrors the branded drug's label which teaches the method, infringement is often difficult to dispute.
    • Technical Questions: A potential dispute could arise over whether Aizant's 120 mg tablets are suitable for administering the claimed "about 360 mg" loading dose (e.g., by taking three tablets), and whether the label instructs such an action.

V. Key Claim Terms for Construction

  • For the ’178 Patent:

    • The Term: "a mixture"
    • Context and Importance: This term's construction is critical to defining the scope of the claim. Practitioners may focus on this term because its interpretation will determine whether the claim is limited to a simple two-component blend of the active ingredient and the specified impurity, or if it can be read more broadly to encompass a final pharmaceutical formulation that includes numerous other excipients.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification discusses producing the final drug product with high quality and purity, which may suggest the "mixture" is the drug product itself (’178 Patent, col. 2:9-15). Claim 1 refers to the mixture comprising the active ingredient "or a salt or solvate thereof," which are forms typically found in final drug products.
      • Evidence for a Narrower Interpretation: The claim explicitly lists only two components, which could support an interpretation that the mixture is defined by and limited to those two components, potentially excluding final formulations with additional ingredients. The patent's title "Compositions of Thienopyrimidine Derivatives" could be argued to refer to the active pharmaceutical ingredient composition prior to formulation with excipients.

  • For the ’198 Patent:

    • The Term: "treating prostate cancer"
    • Context and Importance: The definition of "treating" is central to the method claim. Practitioners may focus on this term because its scope could be disputed. For instance, does "treating" require a specific clinical outcome (e.g., tumor regression, PSA reduction) or does it simply mean administering the drug for the indicated purpose? This is crucial for determining the acts that constitute direct infringement, which Aizant is accused of inducing.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The background discusses androgen deprivation therapy (ADT) as being "valuable in the treatment of prostate cancer," linking treatment to the drug's mechanism of reducing testosterone levels (’198 Patent, col. 1:57-62). This could support a view that administering the drug to achieve this hormonal effect constitutes "treating."
      • Evidence for a Narrower Interpretation: The detailed description and clinical data presented in the patent show specific outcomes, such as achieving and maintaining medical castration levels and reducing PSA levels (’198 Patent, FIG. 1; FIG. 13). A defendant could argue that "treating" should be limited to methods that are proven to achieve such specific clinical endpoints.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all three patents-in-suit. The allegations for inducement are based on the assertion that Aizant's marketing and product labeling for its ANDA Product will intentionally encourage and instruct healthcare providers and patients to use the generic drug in an infringing manner (e.g., Compl. ¶36, ¶46, ¶56). Contributory infringement is alleged on the basis that Aizant's product is especially made or adapted for an infringing use and is not a staple article of commerce suitable for substantial noninfringing use (e.g., Compl. ¶37, ¶47, ¶57).
  • Willful Infringement: Plaintiffs allege that Aizant's infringement is willful and request a declaration that the case is "exceptional" under 35 U.S.C. § 285 (Compl. ¶40, ¶50, ¶60). The basis for this allegation is that Aizant acted "without a reasonable basis for believing that it would not be liable for directly and/or indirectly infringing" the patents, with knowledge of the patents established at least by the date of its ANDA submission and confirmed by its Paragraph IV Notice Letter (Compl. ¶27-28, ¶40).

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

No probative visual evidence provided in complaint.

  • A primary issue for the composition patent ('178) will be one of factual proof: what is the precise chemical composition of Aizant's proposed generic product as detailed in its confidential ANDA? The case may turn on whether that product meets the specific quantitative limitation for a related substance recited in the asserted claims.
  • A core question for the method patents ('198 and '809) will be one of label-driven infringement: does the proposed FDA label for Aizant's generic product instruct or encourage physicians and patients to follow the specific loading dose and maintenance dose regimens claimed in the patents, thereby creating liability for induced infringement?
  • Given that this is an ANDA case premised on a Paragraph IV certification, a central battleground will be patent validity. While the complaint focuses on infringement, the ultimate resolution of the dispute will likely depend on whether Aizant can prove by clear and convincing evidence that the asserted claims of the patents-in-suit are invalid on grounds such as obviousness or lack of written description.