DCT

2:26-cv-00559

Tanabe Pharma Corp v. Azurity Pharmaceuticals Inc

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:26-cv-00559, D.N.J., 01/16/2026
  • Venue Allegations: Plaintiff alleges venue is proper in the District of New Jersey based on Defendant Slayback’s regular and established place of business in Princeton, New Jersey, which Plaintiff asserts Azurity has ratified as its agent or alter ego for its edaravone program. Plaintiff further asserts that Azurity has committed acts of infringement in the district and has availed itself of the forum by previously filing other lawsuits there.
  • Core Dispute: Plaintiff alleges that Defendants' filing of a New Drug Application for a generic oral formulation of edaravone infringes nine patents covering Plaintiff's commercial drug, RADICAVA ORS®.
  • Technical Context: The technology relates to oral suspensions of the drug edaravone for the treatment of Amyotrophic Lateral Sclerosis (ALS), offering a less burdensome alternative to previous intravenous formulations.
  • Key Procedural History: The litigation was initiated under the Hatch-Waxman Act following Defendants' submission of a 505(b)(2) New Drug Application (NDA) to the FDA. Plaintiff received a "Notice Letter" with a Paragraph IV certification from Defendants, asserting noninfringement of certain patents-in-suit. The filing of the complaint triggers a statutory 30-month stay of FDA approval for the accused generic product.

Case Timeline

Date Event
2018-11-02 Priority Date for all Patents-in-Suit
2021-04-27 U.S. Patent No. 10,987,341 Issues
2022-02-08 U.S. Patent No. 11,241,416 Issues
2022-05-12 FDA approves Plaintiff's RADICAVA ORS® (NDA No. 215446)
2022-10-25 U.S. Patent No. 11,478,450 Issues
2023-09-27 Azurity announces acquisition of Slayback Pharma LLC
2023-11-28 U.S. Patent No. 11,826,352 Issues
2024-03-28 FDA grants Orphan Drug Exclusivity for RADICAVA ORS®
2024-04-16 U.S. Patent No. 11,957,660 Issues
2025-01-14 U.S. Patent No. 12,194,025 Issues
2025-04-29 U.S. Patent No. 12,285,409 Issues
2025-05-27 U.S. Patent No. 12,310,946 Issues
2025-11-25 U.S. Patent No. 12,478,611 Issues
2025-12-08 Plaintiff TPC receives Defendants' Notice Letter for NDA No. 221059
2026-01-16 Complaint for Patent Infringement Filed

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

U.S. Patent No. 10,987,341 - *"Edaravone Suspension for Oral Administration"*

  • Issued: April 27, 2021 (’341 Patent)

The Invention Explained

  • Problem Addressed: The patent describes edaravone as a therapeutic agent for ALS, which has historically been administered via injection (’341 Patent, col. 4:30-35). This method imposes a significant burden on ALS patients, who often suffer from muscular weakness and movement disorders, as well as on their caregivers (’341 Patent, col. 4:65-66).
  • The Patented Solution: The invention provides an oral suspension of edaravone that contains edaravone particles, a dispersant, and water (’341 Patent, Abstract). This formulation is designed to be easily swallowed, even by patients with dysphagia, and to achieve a therapeutic effect equivalent to that of an injection, thereby reducing the burden of administration (’341 Patent, col. 4:62-66).
  • Technical Importance: The invention provided a means for oral delivery of an established ALS therapy, improving quality of life and simplifying administration for patients with a progressive neurodegenerative disease. (’341 Patent, col. 4:65-66).

Key Claims at a Glance

  • The complaint asserts at least Independent Claim 1 of the ’341 Patent (Compl. ¶60).
  • Claim 1 requires:
    • An edaravone suspension for human oral administration.
    • Comprising water, edaravone particles dispersed in the water, and a dispersant.
    • The dispersant's function is to maintain the edaravone particles in a solid particle state in the water.
    • The blending amount of edaravone particles is between 0.5% (w/v) and 36% (w/v).
    • The dispersant is selected from a specific group including polyvinyl alcohol, methylcellulose, hypromellose, sucrose fatty acid ester, and polysorbate.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 11,241,416 - *"Edaravone Suspension for Oral Administration"*

  • Issued: February 8, 2022 (’416 Patent)

The Invention Explained

  • Problem Addressed: The technical problem is identical to that described in the ’341 Patent: the burden associated with intravenous administration of edaravone for ALS patients (’416 Patent, col. 2:40-42).
  • The Patented Solution: The ’416 Patent also discloses an oral suspension containing edaravone particles, a dispersant, and water (’416 Patent, Abstract). The focus is on creating a formulation that is easy for patients with dysphagia to take while ensuring proper dispersion and stability of the active pharmaceutical ingredient (’416 Patent, col. 3:10-15).
  • Technical Importance: As with the ’341 Patent, this invention offers a more patient-friendly delivery method for edaravone in the treatment of ALS. (’416 Patent, col. 3:5-8).

Key Claims at a Glance

  • The complaint asserts at least Independent Claim 1 of the ’416 Patent (Compl. ¶70).
  • Claim 1 requires:
    • An edaravone suspension for human oral administration.
    • Comprising water, edaravone particles dispersed in the water, and a dispersant.
    • The dispersant exhibits a "transmission scattering light intensity of 1% or more."
    • The blending amount of the dispersant is between 0.001% (w/v) and 1.0% (w/v).
    • The blending amount of edaravone particles is between 0.5% (w/v) and 36% (w/v).
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 11,478,450 - *"Edaravone Suspension for Oral Administration"*

  • Issued: October 25, 2022 (’450 Patent)
  • Technology Synopsis: This patent addresses the same technical problem as the ’341 and ’416 Patents. It claims a method of treating ALS by orally administering an edaravone formulation with specific pharmacokinetic properties (e.g., mean Cmax and AUC) and dosage parameters. (’450 Patent, Abstract).
  • Asserted Claims: At least Independent Claim 1 is asserted (Compl. ¶80).
  • Accused Features: The complaint alleges that Defendants' proposed generic edaravone oral formulation will meet the method steps and pharmacokinetic parameters claimed in the ’450 Patent (Compl. ¶¶ 79-80).

U.S. Patent No. 11,826,352 - *"Edaravone Suspension for Oral Administration"*

  • Issued: November 28, 2023 (’352 Patent)
  • Technology Synopsis: This patent also relates to an oral edaravone suspension for treating ALS. It claims a suspension that includes a thickening agent and is characterized by a specific viscosity level defined by the International Dysphagia Diet Standardisation Initiative (IDDSI) framework. (’352 Patent, Abstract).
  • Asserted Claims: At least Independent Claim 1 is asserted (Compl. ¶90).
  • Accused Features: The complaint alleges that Defendants' proposed generic edaravone oral formulation is a "partial suspension" that contains the elements of the claimed composition (Compl. ¶¶ 89-90).

U.S. Patent No. 11,957,660 - *"Edaravone Suspension for Oral Administration"*

  • Issued: April 16, 2024 (’660 Patent)
  • Technology Synopsis: This patent is directed to an edaravone suspension for oral administration that notably contains a thickening agent but does not contain a preservative, while still exhibiting a preservative effect. (’660 Patent, Abstract).
  • Asserted Claims: At least Independent Claim 1 is asserted (Compl. ¶100).
  • Accused Features: The complaint alleges that Defendants' proposed generic edaravone oral formulation infringes by having the claimed composition (Compl. ¶¶ 99-100).

The complaint asserts four additional patents: U.S. Patent Nos. 12,194,025; 12,285,409; 12,310,946; and 12,478,611. The allegations for each follow the same pattern as those for the patents detailed above, asserting infringement of at least independent claim 1 and accusing Defendants' proposed edaravone oral formulation (Compl. ¶¶ 108-147). The patents generally relate to pharmaceutical compositions and methods for oral administration of edaravone.

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is Defendants’ proposed edaravone oral formulation "105 mg / 5 mL" for the treatment of ALS, for which Defendants seek FDA approval via NDA No. 221059 (Compl. ¶¶ 2, 23).

Functionality and Market Context

  • The product is intended to be a generic version of Plaintiff’s RADICAVA ORS®, which is the first FDA-approved oral formulation of edaravone (Compl. ¶¶ 2, 6, 23). The complaint alleges, based on review of confidential NDA materials and Defendants' own patent filings (U.S. Patent Nos. 12,343,330 and 12,491,178), that the proposed product is a "partial suspension requiring a crystallization inhibitor" (Compl. ¶¶ 34, 60, 70).
  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not contain or reference a detailed claim chart. The infringement allegations are based on counsel's review of confidential portions of NDA No. 221059 and on publicly available information, including patents assigned to Defendant Slayback (Compl. ¶¶ 29, 34, 60). The narrative theory is that the proposed product contains all elements of the asserted claims, either literally or under the doctrine of equivalents (Compl. ¶¶ 60, 70).

’341 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An edaravone suspension for human oral administration Defendants' proposed product is an edaravone oral formulation for the treatment of ALS (a suspension, per Plaintiff's allegation). ¶¶23, 60 col. 26:1-3
comprising...edaravone particles comprising edaravone dispersed in the water The complaint alleges the product is, at a minimum, a "partial suspension" containing edaravone. ¶60 col. 26:5-6
and a dispersant dispersing the edaravone particles in water such that the dispersant maintains the edaravone particles in a solid particle state in the water The complaint alleges infringement of this limitation without specifying the corresponding component in the accused product. ¶60 col. 26:7-10
wherein a blending amount of the edaravone particles is in a range of 0.5% (w/v) to 36% (w/v) The complaint alleges infringement of this limitation based on review of confidential NDA materials. ¶¶34, 60 col. 26:11-13
and the dispersant is at least one dispersant selected from the group consisting of polyvinyl alcohol, methylcellulose, hypromellose, sucrose fatty acid ester and polysorbate The complaint alleges infringement of this limitation based on review of confidential NDA materials. ¶¶34, 60 col. 26:14-18

’416 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An edaravone suspension for human oral administration Defendants' proposed product is an edaravone oral formulation for the treatment of ALS (a suspension, per Plaintiff's allegation). ¶¶23, 70 col. 25:50-52
comprising...edaravone particles...dispersed in the water; and a dispersant exhibiting a transmission scattering light intensity of 1% or more The complaint alleges the product is a "partial suspension" and that it infringes this limitation, without specifying the component functioning as a dispersant. ¶70 col. 25:53-56
wherein a blending amount of the dispersant is in a range of 0.001% (w/v) to 1.0% (w/v) The complaint alleges infringement of this limitation based on review of confidential NDA materials. ¶¶34, 70 col. 25:57-59
a blending amount of the edaravone particles is in a range of 0.5% (w/v) to 36% (w/v) The complaint alleges infringement of this limitation based on review of confidential NDA materials. ¶¶34, 70 col. 25:60-62

Identified Points of Contention

  • Technical Questions: A primary technical question may be whether the accused product is a "suspension" containing "particles" as claimed, or a "solution." The complaint's reference to Defendants' own patents, which are titled "Stable Pharmaceutical Compositions of Edaravone" and allegedly describe "edaravone solutions," raises the possibility that Defendants will argue their product is a solution and thus does not contain "particles" (’Compl. ¶¶ 27, 29). Plaintiff's characterization of the accused product as a "partial suspension" suggests this will be a central factual dispute (Compl. ¶60).
  • Scope Questions: The dispute may turn on the scope of key claim terms. For instance, what evidence does the complaint provide that an excipient in the accused product functions as a "dispersant...[that] maintains the edaravone particles in a solid particle state" as required by claim 1 of the ’341 Patent? The answer to this question appears to depend entirely on confidential information from the NDA submission (Compl. ¶34).

V. Key Claim Terms for Construction

  • The Term: "edaravone particles"

    • Context and Importance: This term is fundamental to the asserted composition claims, which are directed to a "suspension." If the accused product is determined to be a solution, in which the edaravone is fully dissolved rather than present as solid particles, it may not infringe. The complaint's allegation of a "partial suspension" suggests Plaintiff anticipates a dispute over whether the accused product contains "particles" at all (Compl. ¶60).
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification does not provide an explicit definition that deviates from the ordinary meaning. Parties may argue the plain and ordinary meaning should apply, which could be subject to differing expert interpretations.
      • Evidence for a Narrower Interpretation: The patents consistently describe the invention as a "suspension" and refer to "solid particles containing edaravone" (’341 Patent, col. 5:14-15). The detailed description focuses on particle size distributions (D50 and D90 values), which inherently refers to a solid, non-dissolved phase (’341 Patent, col. 5:21-33). This context may support a narrower construction limited to discernible solid matter.

  • The Term: "dispersant"

    • Context and Importance: Claim 1 of the '341 Patent defines the "dispersant" by its function: "maintaining the edaravone particles in a solid particle state in the water." Claim 1 of the '416 Patent defines it by a physical property: "exhibiting a transmission scattering light intensity of 1% or more." Whether an excipient in Defendants' product meets these functional or physical property limitations will be a key infringement question.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patents list several categories of suitable dispersants, such as polyvinyl alcohol and polysorbate, suggesting the term could cover a range of common pharmaceutical excipients (’341 Patent, col. 5:55-61).
      • Evidence for a Narrower Interpretation: The specific functional language ("maintains...in a solid particle state") or physical property ("transmission scattering light intensity of 1% or more") may be interpreted as limiting the term to only those agents that demonstrably perform the claimed function or possess the claimed property under the conditions outlined in the specification (’416 Patent, col. 4:1-26).

VI. Other Allegations

  • Indirect Infringement: The act of infringement alleged is statutory infringement under 35 U.S.C. § 271(e)(2), which arises from the submission of an NDA seeking approval to market a drug claimed in a patent before its expiration (Compl. ¶61). The complaint also seeks a declaratory judgment that Defendants will induce or contribute to infringement under §§ 271(b) and (c) if the product is commercially manufactured and sold after FDA approval (Compl., Prayer for Relief ¶ B).
  • Willful Infringement: The complaint does not contain an explicit count for willful infringement. However, for each asserted patent, it alleges that "Defendants had actual and constructive notice" of the patent prior to filing their NDA (Compl. ¶¶ 64, 74, 84, 94, 104, 114, 124, 134, 144). Such allegations often form the basis for a later claim of willfulness.

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

  • A core issue will be one of physical state and definitional scope: can the accused product, which Plaintiff alleges is a "partial suspension" and which related defense-side patents may describe as a "solution," be proven to be a "suspension" containing "edaravone particles" within the meaning of the asserted claims?
  • A key evidentiary question will be one of formulation identity: what will the confidential NDA documents reveal about the precise ingredients and physical characteristics of the accused product, and will that evidence establish that the product's excipients function as the claimed "dispersant" and/or "thickening agent"?
  • A central legal and factual question will be one of infringement under the doctrine of equivalents: if the accused product is found not to literally infringe (e.g., if it is a solution), does it perform substantially the same function in substantially the same way to achieve the same result as the claimed suspension, and would such a finding be barred by prosecution history or the prior art?