DCT

2:23-cv-01902

Actelion Pharma US Inc v. Alembic Pharma Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:23-cv-01902, D.N.J., 04/04/2023
  • Venue Allegations: Plaintiff alleges venue is proper because Defendant Alembic Ltd. is a foreign entity subject to personal jurisdiction in the district, and Defendant Alembic Inc. has a principal place of business in New Jersey and has committed acts of infringement in the district.
  • Core Dispute: Plaintiff alleges that Defendant's filing of an Abbreviated New Drug Application (ANDA) to market a generic version of Plaintiff's drug OPSUMIT® constitutes infringement of a patent covering the active pharmaceutical ingredient, macitentan.
  • Technical Context: The technology concerns a chemical compound, macitentan, which functions as an endothelin receptor antagonist for the treatment of pulmonary arterial hypertension (PAH).
  • Key Procedural History: This action was filed under the Hatch-Waxman Act, triggered by Defendant’s notice letter regarding its ANDA submission with a Paragraph IV certification. The complaint notes that Defendant initially filed a Paragraph III certification before converting it to a Paragraph IV certification. The complaint also highlights several prior lawsuits brought by the Plaintiff against other generic drug manufacturers over the same patent, which reportedly resulted in consent judgments where those parties admitted the patent is valid and enforceable.

Case Timeline

Date Event
2000-12-18 ’781 Patent Priority Date
2006-08-22 ’781 Patent Issue Date
2013-10-18 FDA approval for Plaintiff's OPSUMIT® (macitentan)
2017-10-10 Approximate date of Defendant's ANDA submission
2023-02-21 Defendant's Paragraph IV Notice Letter sent to Plaintiff
2023-04-04 Complaint Filing Date

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

U.S. Patent No. 7,094,781 - "Sulfamides and Their Use as Endothelin Receptor Antagonists"

  • Patent Identification: U.S. Patent No. 7,094,781, issued on August 22, 2006.

The Invention Explained

  • Problem Addressed: The patent's background section notes that while endothelin receptor antagonists were known to be useful for treating various diseases (e.g., hypertension, heart failure), existing compounds suffered from weaknesses such as complex synthesis, low solubility, poor pharmacokinetics, or safety problems ('781 Patent, col. 1:56-62).
  • The Patented Solution: The invention discloses a new class of sulfamide compounds built on a pyrimidine core structure. These compounds are described as endothelin receptor antagonists that can be tailored to achieve desirable physicochemical and pharmacokinetic properties, thereby overcoming the deficiencies of prior art compounds ('781 Patent, Abstract; col. 2:1-6).
  • Technical Importance: The patented compounds inhibit the potent vasoconstrictor effects of endothelins, making them therapeutically useful for a range of cardiovascular and inflammatory diseases, most notably pulmonary arterial hypertension ('781 Patent, col. 1:13-24; col. 5:26-37).

Key Claims at a Glance

  • The complaint asserts infringement of claims 1, 5-9, and 11, and reserves the right to assert other claims (Compl. ¶50). Claim 1 is the broadest asserted independent claim.
  • Independent Claim 1 claims a compound of general formula I, which is defined by a large Markush group structure encompassing:
    • A core pyrimidine ring substituted at various positions.
    • A sulfamide group "-NH-SO2-NH-" connecting a substituent R¹ to the pyrimidine core.
    • A substituent R³ (aryl or heteroaryl) attached to the pyrimidine core.
    • A substituent R² representing various chemical groups attached to the pyrimidine core.
  • Independent Claim 11 claims a specific list of named compounds, including various sulfamic acid amides, or their pharmaceutically acceptable salts ('781 Patent, col. 142:55 - col. 144:60).

III. The Accused Instrumentality

Product Identification

The accused instrumentality is Defendant's generic macitentan 10 mg oral tablets, for which it seeks FDA approval via Abbreviated New Drug Application (ANDA) No. 211128 (Compl. ¶16).

Functionality and Market Context

  • The accused "ANDA Product" is a generic version of Plaintiff's branded drug, OPSUMIT®, which is approved for the treatment of pulmonary arterial hypertension (PAH) (Compl. ¶16, ¶31).
  • The complaint alleges that the ANDA Product contains macitentan as its active pharmaceutical ingredient (Compl. ¶51). The lawsuit was triggered by Defendant's filing of the ANDA seeking approval to market this product in the United States prior to the expiration of the '781 patent (Compl. ¶16, ¶35).
  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The infringement allegation under 35 U.S.C. § 271(e)(2) is an "artificial" act based on the submission of the ANDA. The core of the dispute is whether the product described in the ANDA, if commercially marketed, would literally infringe the asserted patent claims. The complaint's theory is based on direct chemical identity.

’781 Patent Infringement Allegations

Claim Element (from Independent Claim 11) Alleged Infringing Functionality Complaint Citation Patent Citation
A compound which is one of the specifically enumerated chemical names recited in the claim, or a pharmaceutically acceptable salt thereof. The ANDA Product contains macitentan as the active ingredient. The complaint alleges that "The chemical name of the compound macitentan is one of the chemical names recited in Claim 11 of the '781 patent." ¶51, ¶52 col. 142:55-144:60

Identified Points of Contention

  • Identity Question: The central dispute will be a question of fact: is the compound macitentan, the active ingredient in Alembic's ANDA Product, structurally identical to one of the specific compounds enumerated by chemical name in Claim 11 of the '781 patent? The complaint makes this assertion directly but provides no supporting structural analysis.
  • Evidentiary Question: What evidence will be required to prove or disprove this alleged identity? The analysis will likely depend on expert testimony comparing the chemical structure of macitentan with the structures corresponding to the chemical nomenclature used in the patent's claims.

V. Key Claim Terms for Construction

In this chemical compound case, the primary dispute is less likely to center on the construction of ambiguous terms and more on the question of direct structural identity between the accused product and the claimed invention.

  • The Term: The specific chemical names listed in Claim 11.
  • Context and Importance: The outcome of the infringement analysis hinges on whether the compound "macitentan" falls within the scope of any of the specific chemical names recited in Claim 11. The dispute is not over the meaning of a functional term, but rather the precise chemical structure defined by the patent's language. Practitioners may focus on this issue because it is a dispositive, binary question of identity.
  • Intrinsic Evidence for Interpretation:
    • Evidence for Plaintiff's Position (Identity): The Plaintiff will argue that standard chemical nomenclature rules demonstrate that the structure of macitentan is identical to one of the structures explicitly named in Claim 11. The complaint asserts this identity as a fact (Compl. ¶52).
    • Evidence for Defendant's Position (Non-Identity): The Defendant may argue that the specific chemical structure of macitentan does not correspond to any of the compounds precisely defined by the names in Claim 11. The patent specification, including its numerous synthesis examples (e.g., Examples 1-216), provides explicit structural information for many compounds, which could be used to argue for a strict and literal reading of the claimed chemical names that excludes macitentan.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that if Alembic were to commercialize its ANDA Product, it would induce and contribute to infringement by third parties (e.g., patients and physicians) under 35 U.S.C. §§ 271(b) and (c) (Compl. ¶60, ¶63). This allegation is based on the eventual sale and marketing of the product with labeling that instructs on its infringing use.
  • Willful Infringement: The complaint alleges that any post-launch commercial activity would constitute willful infringement. This is based on allegations of pre-suit knowledge of the '781 patent since at least October 2017 and, notably, knowledge of multiple consent judgments in prior litigation against other generic manufacturers where the validity and enforceability of the '781 patent were allegedly admitted (Compl. ¶36-37, ¶42-49, ¶62). The complaint also pleads that the case is "exceptional" under 35 U.S.C. § 285, citing Alembic's "failure to comply with the affirmative duty of care" in converting its certification from Paragraph III to Paragraph IV (Compl. ¶65).

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

  • A central issue will be one of chemical identity: does the compound macitentan, the active ingredient in the accused ANDA product, have a chemical structure that is identical to one of the specific compounds enumerated in Claim 11 of the ’781 patent? The resolution of this factual question will likely be dispositive on the issue of infringement.
  • A key secondary issue will be case exceptionality: did the defendant's decision to file a Paragraph IV certification, allegedly with full knowledge of prior litigations where the '781 patent's validity and enforceability were upheld by consent judgment, constitute conduct that renders this case "exceptional" under 35 U.S.C. § 285, potentially exposing the defendant to attorneys' fees?