DCT

2:25-cv-00801

Axsome Malta Ltd v. Hetero USA Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-00801, D.N.J., 01/29/2025
  • Venue Allegations: Plaintiff Axsome alleges venue is proper in the District of New Jersey because Defendant Hetero USA Inc. maintains a regular and established physical place of business in the district. For the foreign-based Hetero entities, Axsome alleges venue is proper because they are foreign companies that can be sued in any judicial district and have sufficient contacts with the U.S. and the state of New Jersey.
  • Core Dispute: Plaintiff alleges that Defendants' submission of an Abbreviated New Drug Application (ANDA) to market a generic version of the drug solriamfetol constitutes an act of infringement of a patent covering methods for safely administering the drug to lactating women.
  • Technical Context: The technology concerns a specific pharmaceutical dosing regimen designed to minimize a nursing infant's exposure to solriamfetol—a drug used to treat excessive daytime sleepiness—when taken by a lactating mother.
  • Key Procedural History: This lawsuit was triggered by Defendants' filing of ANDA No. 218654 and a subsequent Paragraph IV certification notice letter, dated on or after November 19, 2024, alleging that U.S. Patent No. 12,102,609 is invalid, unenforceable, or will not be infringed. This was the sixth such notice letter Hetero had sent to Axsome regarding its solriamfetol product, with prior letters addressing different patents in the same family.

Case Timeline

Date Event
2022-12-30 Earliest Priority Date for ’609 Patent
2023-08-15 Hetero sends First Paragraph IV Notice Letter to Axsome
2023-12-01 Hetero sends Second Paragraph IV Notice Letter to Axsome
2024-03-11 Hetero sends Third Paragraph IV Notice Letter to Axsome
2024-09-23 Hetero sends Fourth Paragraph IV Notice Letter to Axsome
2024-10-01 U.S. Patent No. 12,102,609 Issues
2024-10-10 Hetero sends Fifth Paragraph IV Notice Letter to Axsome
2024-11-19 Hetero sends Sixth Paragraph IV Notice Letter to Axsome ('609 Patent)
2025-01-29 Complaint Filed

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

U.S. Patent No. 12,102,609 - "Methods of Administering Solriamfetol to Lactating Women"

  • Patent Identification: U.S. Patent No. 12,102,609, "Methods of Administering Solriamfetol to Lactating Women," issued October 1, 2024 (the "'609 Patent").

The Invention Explained

  • Problem Addressed: The patent addresses the challenge of administering solriamfetol, a drug for treating excessive daytime sleepiness, to a lactating mother without exposing the nursing infant to potentially harmful levels of the drug (’609 Patent, col. 1:12-17). Nonclinical studies indicated that solriamfetol is excreted into breast milk, with concentrations potentially higher than those in the mother's plasma, creating a risk of adverse events for the infant (’609 Patent, col. 7:22-26).
  • The Patented Solution: The patent discloses a method that involves a specific timing regimen. After a mother takes an oral dose of solriamfetol, she is to wait a defined period—for example, at least five hours—before breastfeeding her infant (’609 Patent, Abstract). This waiting period is designed to allow the drug concentration in the breast milk to fall below its peak level (Tmax), which the patent identifies as occurring at a median of approximately 1.1 hours, thereby reducing the total drug dose transferred to the infant (’609 Patent, col. 2:20-28, col. 2:58-63).
  • Technical Importance: The described method provides a protocol that could allow lactating women suffering from conditions like narcolepsy or obstructive sleep apnea to use solriamfetol while simultaneously reducing the risk of drug exposure to their breastfeeding infants (’609 Patent, col. 15:6-9).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶37).
  • Essential elements of Independent Claim 1 include:
    • A method for decreasing the potential for adverse events from solriamfetol in an infant fed breast milk.
    • Orally administering a once-daily dose of "about 150 mg" of solriamfetol to the human subject (the mother).
    • Feeding the infant breast milk from the subject "at least about 5 hours after" the administration.
    • Wherein following this method results in a cumulative amount of solriamfetol excreted in breast milk over 8 hours of "about 0.26 mg or lower." (’609 Patent, col. 29:5-16).
  • The complaint does not explicitly reserve the right to assert dependent claims, but this is standard practice in such litigation.

III. The Accused Instrumentality

Product Identification

  • Defendants’ proposed generic solriamfetol oral tablets, for which Abbreviated New Drug Application (“ANDA”) No. 218654 was submitted to the FDA for approval (“Hetero’s Proposed Product”) (Compl. ¶¶1, 16).

Functionality and Market Context

  • Hetero's Proposed Product is a generic version of Axsome’s Sunosi®, a dopamine and norepinephrine reuptake inhibitor (DNRI) marketed to improve wakefulness in adults with excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea (Compl. ¶¶2, 10). The complaint alleges that the '609 Patent’s claims cover methods of using Sunosi® (Compl. ¶10). The infringement allegation is statutory, based on the act of filing the ANDA to seek approval for marketing the generic drug for the same indication prior to the expiration of the ’609 Patent (Compl. ¶¶27, 37). The complaint alleges that Hetero's Proposed Product is designed for a use that infringes the patent and lacks a substantial non-infringing use (Compl. ¶41). Figure 1 of the patent, which shows the mean concentration of solriamfetol in plasma versus breast milk over 72 hours, provides the pharmacokinetic rationale underlying the claimed method that Axsome alleges will be infringed (Compl. Ex. A, p. 17).

IV. Analysis of Infringement Allegations

’609 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method for decreasing the potential for adverse events from solriamfetol in an infant fed breast milk... The complaint alleges Hetero's Proposed Product, a generic version of Sunosi®, is intended for the same medical indications and that its use by lactating women as directed by its label will constitute infringement of the patented method (Compl. ¶¶10, 40). ¶10, ¶40 col. 1:12-17
administering solriamfetol orally at a once-daily dose of about 150 mg to the subject; and The complaint alleges Hetero seeks approval to market generic solriamfetol tablets, which are equivalent to the 150 mg dosage of the branded Sunosi® product, and that the product's eventual label will instruct or encourage administration of this dose (Compl. ¶10, ¶40). ¶10, ¶40 col. 29:10-11
feeding the infant breast milk from the subject at least about 5 hours after administering...; Axsome's infringement theory is premised on the allegation that Hetero's product label will instruct or encourage lactating mothers to wait for a period of time consistent with the claim, thereby inducing infringement by the end-user to ensure infant safety (Compl. ¶40). ¶40 col. 29:12-14
wherein the cumulative amount of solriamfetol excreted in breast milk over 8 hours is about 0.26 mg or lower. The complaint does not provide specific allegations on this resulting limitation. Axsome's position is likely that this outcome is an inherent result of following the preceding steps of the claimed method as taught in the patent specification (Compl. Ex. A, Fig. 2). ¶37 col. 29:15-16
  • Identified Points of Contention:
    • Scope Questions: A central question for the court will be whether the proposed label for Hetero's generic product will actively instruct or encourage users to perform the specific steps of the patented method. The dispute may turn on whether the label language directly recommends waiting "at least about 5 hours" or if it contains more general warnings that Axsome will argue lead to the same result.
    • Technical Questions: A likely point of contention will be the validity of the claims. Hetero may argue that advising a patient to wait a few hours after drug administration before breastfeeding to avoid peak drug concentration (Tmax) is a well-known and obvious pharmacokinetic principle. The defense would question whether specifying a period of "at least about 5 hours" constitutes a non-obvious invention over what a person of ordinary skill in the art would have already considered standard practice for any drug excreted in breast milk.

V. Key Claim Terms for Construction

  • The Term: "about"

    • Context and Importance: This term appears in relation to the dosage ("about 150 mg"), the waiting period ("at least about 5 hours"), and the resulting excreted amount ("about 0.26 mg"). The scope of "about" is critical for determining the literal boundaries of the claim and, therefore, what constitutes infringement. Practitioners may focus on this term because its construction will define how much deviation from the specified numbers is permissible while still falling within the claim.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification explicitly defines "about" to "encompass variations of ±10%, ±5%, ±1%, ±0.5%, or even ±0.1% of the specified amount," which could support a more flexible range around the recited values (’609 Patent, col. 4:11-16).
      • Evidence for a Narrower Interpretation: A party could argue that the term should be interpreted more narrowly in light of the patent's reliance on specific data from a clinical study (’609 Patent, col. 15:43-66). The argument would be that "about" should be constrained by the precision and context of the scientific measurements that form the basis of the invention.

  • The Term: "feeding the infant breast milk"

    • Context and Importance: This term defines the key action that must be delayed. Its construction is important for determining precisely what activity is proscribed during the "at least about 5 hours" waiting period.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent's objective is to reduce infant exposure by avoiding peak drug concentrations (’609 Patent, col. 2:20-28). This purpose may support interpreting "feeding" to mean any act of providing breast milk to the infant that begins after the 5-hour mark.
      • Evidence for a Narrower Interpretation: The clinical study described in the patent involved instructing subjects to "refrain from breastfeeding their infants for 72 hours postdose" (’609 Patent, col. 16:41-43). A party could argue that this suggests a more restrictive interpretation, although the claim language itself appears less stringent than the study protocol.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both inducement and contributory infringement. The inducement claim is based on the allegation that Hetero’s product labeling will instruct physicians and patients to use the generic drug in a manner that infringes the ’609 Patent (Compl. ¶40). The contributory infringement claim alleges that Hetero knows its product is designed for an infringing use and lacks a substantial non-infringing use, though this may be contested given the drug can be used by non-lactating patients (Compl. ¶41).
  • Willful Infringement: The complaint establishes that Hetero had pre-suit knowledge of the ’609 Patent via the Paragraph IV notice letter sent on or after November 19, 2024 (Compl. ¶35). While not using the word "willful," the complaint requests a judgment that the case is "exceptional" and seeks attorneys' fees under 35 U.S.C. § 285, which is consistent with an allegation of willful or egregious infringement (Compl. ¶44, ¶(J)).

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

  • A core issue will be one of induced infringement: Will the language on the final, FDA-approved label for Hetero's generic product be found to specifically instruct or encourage lactating mothers to wait "at least about 5 hours" before breastfeeding, or will its warnings be too general to support a finding of inducement?
  • A key validity question will be one of obviousness: Was the claimed method—specifically the five-hour waiting period—an obvious step for a skilled artisan to take to minimize infant exposure, based on general pharmacokinetic principles and publicly available information about solriamfetol's properties at the time of the invention?
  • A central claim construction and validity dispute may arise from the resulting-clause limitation "wherein the cumulative amount of solriamfetol excreted...is about 0.26 mg or lower." The court will need to determine if this phrase renders the claim indefinite or if it is merely an inherent, non-limiting result of performing the method's active steps.