DCT

2:25-cv-05709

Fennec Pharma Inc v. Cipla Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-05709, D.N.J., 05/27/2025
  • Venue Allegations: Venue is alleged to be proper against Cipla USA due to its regular and established place of business in Warren, New Jersey, and against its foreign parent Cipla Ltd. on the basis that it may be sued in any judicial district where personal jurisdiction exists.
  • Core Dispute: Plaintiff alleges that Defendants' filing of an Abbreviated New Drug Application (ANDA) for a generic sodium thiosulfate injection constitutes an act of infringement of a patent covering methods for reducing chemotherapy-induced hearing loss in children.
  • Technical Context: The technology concerns pharmaceutical formulations designed to mitigate ototoxicity (hearing loss), a significant and often irreversible side effect of cisplatin-based chemotherapy, particularly in pediatric cancer patients.
  • Key Procedural History: The complaint notes that the asserted patent is a continuation of two parent patents that are the subject of a prior, ongoing lawsuit between the same parties in the same district. Plaintiff’s product, PEDMARK®, received FDA approval in September 2022 and was granted seven years of orphan-drug exclusivity. The complaint also alleges that Defendants were given actual notice of the patent-in-suit’s allowed claims one week prior to its issuance.

Case Timeline

Date Event
2018-07-03 Priority Date for U.S. Patent No. 12,311,026
2022-09-20 FDA Approval of Plaintiff's PEDMARK® product
2023-01-10 Prior lawsuit filed by Fennec against Cipla on parent patents
2023-01-25 FDA grants orphan-drug exclusivity for PEDMARK®
2025-05-20 Plaintiff notifies Defendant of the '026 Patent's impending issuance
2025-05-27 U.S. Patent No. 12,311,026 Issues
2025-05-27 Complaint Filed

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

U.S. Patent No. 12,311,026 - "Therapeutic Uses for Sodium Thiosulfate Formulations," issued May 27, 2025

The Invention Explained

  • Problem Addressed: The patent addresses the problem of ototoxicity—progressive, irreversible hearing loss—caused by platinum-based chemotherapeutics like cisplatin, which are critical for treating various pediatric cancers. This side effect is particularly damaging for young children who rely on normal hearing for cognitive and psychosocial development (’026 Patent, col. 1:29-48).
  • The Patented Solution: The invention provides a method for reducing this hearing loss by administering a specific pharmaceutical composition of sodium thiosulfate (STS). The core of the patented solution is a formulation of STS at a particular concentration and pH range that, critically, is free of borate ions, which are distinguished from other potential buffers or stabilizers (’026 Patent, Abstract; col. 24:50-54). The patent also details a process for formulating the drug product, including steps for dissolving, filtering, and sterilizing the composition (’026 Patent, FIG. 6).
  • Technical Importance: This approach provides a method to protect pediatric patients from a debilitating side effect of an essential cancer therapy, potentially improving quality of life without compromising the anti-tumor efficacy of the chemotherapy (’026 Patent, col. 1:48-53).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶7).
  • The essential elements of independent claim 1 are:
    • A method of reducing ototoxicity in a pediatric patient receiving a platinum-based chemotherapeutic.
    • The method comprises administering an effective amount of a pharmaceutical composition.
    • The composition comprises sodium thiosulfate at a concentration of about 0.5 M.
    • The composition also comprises a stabilizer or mixture of stabilizers from a specified list (a Markush group) that includes glycine and tromethamine.
    • The composition is adjusted, if necessary, to a pH between 6.5 and 8.9.
    • The composition comprises no borate ions.
  • The complaint does not explicitly reserve the right to assert additional claims, though such a reservation is standard practice in patent litigation.

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is Defendants' generic sodium thiosulfate injection product, for which they filed Abbreviated New Drug Application (“ANDA”) No. 218028 with the FDA (Compl. ¶12).

Functionality and Market Context

  • The accused product is a generic version of Plaintiff’s FDA-approved PEDMARK® injection and is intended for the same therapeutic use: "reducing the risk of ototoxicity, induced by cisplatin chemotherapy in pediatric patients" (Compl. ¶8, ¶12).
  • The complaint alleges that Cipla’s ANDA seeks approval to market its product prior to the expiration of the ’026 Patent, which would displace sales of PEDMARK®, the only therapy currently approved for this indication (Compl. ¶8, ¶13, ¶28).

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

The infringement theory is based on the submission of the ANDA under 35 U.S.C. § 271(e)(2). The complaint alleges that the proposed label for Cipla's ANDA Product will instruct medical professionals to use the product in a manner that directly infringes at least claim 1 of the ’026 Patent (Compl. ¶45).

'026 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of reducing ototoxicity in a pediatric patient receiving a platinum based chemotherapeutic for the treatment of cancer sensitive to the platinum based chemotherapeutic... The proposed label for the Cipla ANDA Product will instruct its use for reducing the risk of ototoxicity induced by cisplatin chemotherapy in pediatric patients. ¶12, ¶45 col. 1:29-39
...comprising administering an effective amount of a pharmaceutical composition comprising sodium thiosulfate at a concentration of about 0.5 M... The Cipla ANDA Product is alleged to be a generic copy of PEDMARK®, which contains about 0.5 M sodium thiosulfate, and the label will instruct its administration. ¶9, ¶45 col. 4:5-10
...and a stabilizer or mixture of stabilizers selected from [a specified Markush group]... The complaint alleges infringement of claim 1, which requires a stabilizer from the claimed list, and states the Cipla ANDA essentially copies the PEDMARK® label. ¶42, ¶45 col. 57:40-44
...wherein the pharmaceutical composition is adjusted if necessary to achieve a pH between 6.5 and 8.9... The product will be used at a pH between 6.5 and 8.9, as this is a required parameter of the infringing method and a characteristic of the reference product, PEDMARK®. ¶9, ¶42, ¶45 col. 4:36-38
...and wherein the pharmaceutical composition comprises no borate ions. The complaint explicitly alleges that the infringing method uses a pharmaceutical composition that contains no borate ions. ¶38, ¶42, ¶45 col. 57:48-49
  • Identified Points of Contention:
    • Scope Questions: What is the scope of the term "stabilizer"? The claim recites a long list of potential stabilizers. A central question is whether a compound in the accused product must perform a specific "stabilizing" function distinct from pH buffering to meet this limitation, or if its mere presence as a listed compound suffices.
    • Evidentiary Questions: What evidence does the complaint provide that the Cipla ANDA product contains a "stabilizer" from the specific Markush group in claim 1? The allegation currently rests on "information and belief" and the assertion that the generic label will copy the branded label (Compl. ¶12, ¶45). The contents of the actual ANDA submission, once produced in discovery, will be critical to substantiating this element of infringement.

V. Key Claim Terms for Construction

  • The Term: "stabilizer"

    • Context and Importance: Practitioners may focus on this term because infringement of claim 1 requires the presence of a stabilizer from a specific list. Defendants may argue that their formulation's excipient is merely a pH adjusting agent and not a "stabilizer" within the meaning of the patent, or that it is not a member of the claimed group.
    • Intrinsic Evidence for a Broader Interpretation: The patent specification provides a very long list of compounds under the heading of "Buffers," which includes the specific stabilizers recited in claim 1, such as glycine and tromethamine (’026 Patent, col. 21:26-51). Plaintiff may argue that any compound from this list used to maintain pH inherently functions as a stabilizer in the context of the invention.
    • Intrinsic Evidence for a Narrower Interpretation: The patent uses the term "stabilizer or mixture of stabilizers" in the claim, which could be argued to imply a function beyond simple pH adjustment (’026 Patent, col. 57:40-44). The specification also lists "Stabilizers" as a separate category of excipients from "Buffering agents," suggesting the patentee may have viewed them as distinct (’026 Patent, col. 25:17-24, 42-56).

  • The Term: "no borate ions"

    • Context and Importance: This negative limitation is a defining feature of the claim. The dispute will likely center on whether this requires the absolute absence of borate ions, or merely that they are not an intentionally added ingredient.
    • Intrinsic Evidence for a Broader Interpretation (favoring patentee): Plaintiff will likely argue that "no borate ions" means none are added as a functional excipient, distinguishing the claimed invention from prior art or alternative formulations that might use borate buffers. The explicit recitation draws a clear line for infringement.
    • Intrinsic Evidence for a Narrower Interpretation (favoring accused infringer): The claim language is absolute ("comprises no borate ions") (’026 Patent, col. 57:48-49). In other parts of the specification, the patentee used qualified language like "essentially no sodium thiosulfate pentahydrate" (’026 Patent, col. 17:36-37). Defendant may argue this choice of absolute language means that the presence of even trace amounts of borate ions, perhaps as a manufacturing impurity, would place the accused product outside the scope of the claim.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement, asserting that the proposed label for the Cipla ANDA Product will instruct, encourage, and suggest that physicians and patients use the product in a manner that infringes the ’026 Patent (Compl. ¶45). It further alleges the product "is not a staple article of commerce and has no substantial approved uses that do not infringe" (Compl. ¶47).
  • Willful Infringement: The complaint alleges that Defendants have "actual knowledge of the '026 Patent" based on an email sent from Plaintiff's counsel to Defendants' counsel on May 20, 2025, which provided notice of the patent's allowed claims before its official issuance (Compl. ¶41). While the word "willful" is not used, this allegation of pre-suit knowledge, combined with the request for attorneys' fees for an "exceptional" case, lays the foundation for a willfulness claim (Compl. ¶54).

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

  • A core issue will be one of evidentiary proof: can Plaintiff demonstrate, based on the contents of the ANDA filing and chemical analysis, that the accused generic product is formulated with both a "stabilizer" from the specific list recited in claim 1 and a complete absence of "borate ions"? The case may turn on the precise chemical composition of a product that is not yet on the market.
  • A second central question will be one of claim construction: how will the court define "stabilizer"? The resolution will determine whether an excipient that primarily functions as a pH buffer can satisfy this limitation, a distinction that could be dispositive for infringement.
  • Finally, the case raises a question of negative limitation scope: what is the threshold for "no borate ions"? The court will need to decide if this term requires absolute, undetectable absence or if it is met so long as borates are not intentionally added as an excipient, a determination with significant implications for both infringement and validity analyses.