DCT

3:26-cv-02044

Xeris Pharma Inc v. Somerset Therap LLC

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:26-cv-02044, D.N.J., 02/26/2026
  • Venue Allegations: Venue is alleged to be proper in the District of New Jersey because multiple defendants maintain their principal places of business in the state, are registered to do business there, and have committed the alleged acts of infringement (the submission of Abbreviated New Drug Applications, or ANDAs) from their New Jersey locations.
  • Core Dispute: Plaintiffs allege that Defendants' submission of ANDAs to the FDA seeking to market generic versions of Plaintiffs' RECORLEV® (levoketoconazole) product constitutes an act of patent infringement under the Hatch-Waxman Act.
  • Technical Context: The technology involves methods of treating endogenous hypercortisolemia (Cushing's syndrome) with levoketoconazole, specifically managing drug-drug interactions when co-administered with other common medications.
  • Key Procedural History: The action was filed within 45 days of Plaintiffs' receipt of notice letters regarding Defendants' ANDA submissions and Paragraph IV certifications, entitling Plaintiffs to an automatic 30-month stay of FDA approval for the generic products.

Case Timeline

Date Event
2019-03-04 Priority Date for '393, '547, '940, and '096 Patents
2021-06-01 '393 Patent Issued
2021-10-01 Xeris Pharmaceuticals, Inc. acquires Strongbridge Biopharma plc (approximate)
2021-12-30 FDA approves New Drug Application (NDA) for RECORLEV®
2022-03-22 '547 Patent Issued
2024-02-20 '940 Patent Issued
2025-08-05 '096 Patent Issued
2026-02-06 Somerset Defendants send Notice Letter to Plaintiffs
2026-02-10 Torrent Defendants send Notice Letter to Plaintiffs
2026-02-26 Complaint Filed

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

U.S. Patent No. 11,020,393 - "Methods of Treating Disease With Levoketoconazole"

Issued June 1, 2021

The Invention Explained

  • Problem Addressed: The patent addresses the challenge of treating patients who suffer from both Cushing's syndrome (a disease of excess cortisol) and type 2 diabetes mellitus. Specifically, it recognizes that levoketoconazole, used to treat Cushing's, can inhibit the clearance of metformin, a common diabetes drug, thereby increasing a patient's systemic exposure to metformin and raising the risk of adverse events '393 Patent, col. 3:45-54 '393 Patent, col. 10:1-17
  • The Patented Solution: The patent claims a method to manage this drug-drug interaction. The method involves administering levoketoconazole using a titration scheme, monitoring the patient for specific "dose limiting events" (such as decreased fasting glucose, abnormal kidney function, or low Vitamin B-12 levels), and adjusting the dosage if the patient shows intolerance '393 Patent, abstract '393 Patent, col. 11:1-10 This provides a structured protocol for safely co-administering the two drugs.
  • Technical Importance: The invention offers a systematic approach to enable the concurrent use of an important cortisol synthesis inhibitor and a first-line diabetes therapy, mitigating safety risks from their interaction.

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 Compl. ¶87
  • The essential elements of Claim 1 are:
    • A method of treating persistent or recurrent Cushing's syndrome in a subject who also has type 2 diabetes and is being co-administered metformin.
    • The method comprises administering a therapeutically effective amount of levoketoconazole, where this amount is determined via a "titration scheme."
    • During the titration, monitoring the subject for a "dose limiting event," defined as a decreased fasting glucose level, abnormal kidney function, and/or a low Vitamin B-12 level.
    • If the subject does not tolerate an increased dose, setting the patient's dose to the difference between the further increased dose and the last incremental value.
  • The complaint alleges infringement either literally or under the doctrine of equivalents and reserves the right to assert additional claims Compl. ¶91

U.S. Patent No. 11,278,547 - "Methods of Treating Disease With Levoketoconazole"

Issued March 22, 2022

The Invention Explained

  • Problem Addressed: This patent addresses the same fundamental drug-drug interaction as the '393 Patent but focuses on a specific, potentially more complex, patient sub-population: Cushing's syndrome patients with type 2 diabetes who have already undergone surgery or radiation to treat their Cushing's syndrome '547 Patent, col. 10:29-37
  • The Patented Solution: The patent claims a method tailored to this patient group. It involves administering levoketoconazole via a titration scheme and monitoring for the same dose-limiting events as the '393 Patent. However, upon experiencing a dose-limiting event, this method explicitly requires reducing the amount of metformin administered to the subject, directly addressing the increased metformin exposure '547 Patent, abstract '547 Patent, claim 1
  • Technical Importance: The invention provides a specialized treatment protocol for a subset of patients who have not been cured by prior invasive treatments, offering a way to manage their ongoing therapy with levoketoconazole and metformin.

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 Compl. ¶105
  • The essential elements of Claim 1 are:
    • A method of treating Cushing's syndrome in a subject who has had previous surgery or radiation, also has type 2 diabetes, and is being co-administered metformin.
    • The method comprises administering a therapeutically effective amount of levoketoconazole determined via a "titration scheme."
    • During the titration, monitoring the subject for a "dose limiting event" (decreased fasting glucose, abnormal kidney function, and/or low Vitamin B-12).
    • If a dose-limiting event is experienced, reducing the amount of metformin administered to the subject.
  • The complaint alleges infringement either literally or under the doctrine of equivalents and reserves the right to assert additional claims Compl. ¶109

U.S. Patent No. 11,903,940 - "Methods of Treating Disease With Levoketoconazole"

Issued February 20, 2024

Technology Synopsis

This patent claims a method of treating Cushing's syndrome in patients who are also being treated with a substrate of the organic cation transporter 2 (OCT2), a protein involved in drug clearance '940 Patent, abstract The method involves administering levoketoconazole via a titration scheme, monitoring for dose-limiting events caused by increased exposure to the OCT2 substrate, and reducing the amount of the OCT2 substrate if such an event occurs '940 Patent, claim 1 Metformin is identified as a key OCT2 substrate '940 Patent, col. 15:4-5

Asserted Claims & Accused Features

  • Asserted Claims: At least independent claim 1 Compl. ¶123
  • Accused Features: The proposed generic product's labeling is alleged to instruct for the co-administration of levoketoconazole with metformin (an OCT2 substrate), including monitoring for dose-limiting events and reducing the metformin dosage accordingly Compl. ¶¶124-125

U.S. Patent No. 12,377,096 - "Methods of Treating Disease With Levoketoconazole"

Issued August 5, 2025

Technology Synopsis

This patent is directed to a method of treating Cushing's syndrome in patients co-administered a substrate of the multidrug and toxin extrusion transporter 1 (MATE1) '096 Patent, abstract The method requires administering levoketoconazole via titration, monitoring for dose-limiting events related to increased MATE1 substrate exposure, and reducing the MATE1 substrate amount if an event occurs '096 Patent, claim 1 Metformin is also a substrate for MATE1 '096 Patent, col. 13:45-50

Asserted Claims & Accused Features

  • Asserted Claims: At least independent claim 1 Compl. ¶141
  • Accused Features: The infringement theory is based on the proposed generic label, which is alleged to instruct for use with metformin (a MATE1 substrate) in a manner that includes monitoring and dose reduction steps as claimed Compl. ¶¶142-143

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are the generic levoketoconazole 150 mg oral tablets for which the Somerset and Torrent Defendants have filed ANDAs (the "Somerset ANDA Product" and "Torrent ANDA Product") Compl. ¶66 Compl. ¶73 Compl. ¶76 Compl. ¶83

Functionality and Market Context

The products are generic versions of Plaintiffs' RECORLEV® drug, intended to be therapeutically equivalent Compl. ¶74 Compl. ¶84 The infringement allegations are not based on the composition of the tablets themselves, but on their intended use as will be specified in the Defendants' proposed product labeling. The complaint alleges, on information and belief, that these labels will instruct healthcare providers to prescribe the generic products for treating Cushing's syndrome in a manner that directly follows the steps of the asserted patents, including co-administration with metformin, dose titration, monitoring for specific adverse events, and adjusting dosages accordingly Compl. ¶88 Compl. ¶106 Compl. ¶124 Compl. ¶142 The defendants are alleged to be targeting the same market as RECORLEV® and intend to displace its sales Compl. ¶38 Compl. ¶54

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

'393 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating persistent or recurrent Cushing's syndrome in a subject in need thereof, wherein the subject also has type 2 diabetes mellitus and is being co-administered metformin... The proposed Somerset ANDA Product labeling allegedly involves treating adult patients with Cushing's syndrome who also have type 2 diabetes and are being co-administered metformin. ¶88; ¶89 col. 10:1-17
administering a therapeutically effective amount of levoketoconazole... wherein the therapeutically effective amount... is determined via a titration scheme, The proposed labeling allegedly instructs administering a therapeutically effective amount of levoketoconazole determined via a titration scheme. ¶88 col. 11:1-10
during the levoketoconazole titration scheme, monitoring the subject for a dose limiting event wherein the dose limiting event is a decreased fasting glucose level, abnormal kidney function, and/or a low Vitamin B-12 level; The proposed labeling allegedly instructs monitoring for dose-limiting events such as decreased fasting glucose, abnormal kidney function, and/or low Vitamin B-12 level. ¶88 col. 11:59-67
and wherein if the subject does not tolerate the increased dose, the dose for the patient is equal to the difference between the further increased dose and the incremental value for the last cycle repetition. The complaint alleges the proposed labeling directs a reduction in the amount of metformin administered if a dose-limiting event occurs, which is a method of responding to intolerance. ¶88 col. 11:5-10

'547 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating Cushing's syndrome in a subject... wherein the subject has had previous surgery or radiation to treat the subject's Cushing syndrome, [and also has type 2 diabetes and is being co-administered metformin]... The proposed Somerset ANDA Product labeling allegedly involves treating adult patients with Cushing's syndrome who have had previous surgery or radiation and who also have type 2 diabetes and are co-administered metformin. ¶106 col. 10:29-37
administering a therapeutically effective amount of levoketoconazole... wherein the therapeutically effective amount... is determined via a titration scheme, The proposed labeling allegedly instructs administering a therapeutically effective amount of levoketoconazole determined via a titration scheme. ¶106 col. 11:1-10
during the levoketoconazole titration scheme, monitoring the subject for a dose limiting event wherein the dose limiting event is a decreased fasting glucose level, abnormal kidney function, and/or a low Vitamin B-12 level; The proposed labeling allegedly instructs monitoring for dose-limiting events such as decreased fasting glucose, abnormal kidney function, and/or low Vitamin B-12 level. ¶106 col. 11:59-67
and if the subject experiences a dose limiting event, reducing the amount of metformin... administered to the subject. The proposed labeling allegedly instructs reducing the amount of metformin administered if the subject experiences a dose-limiting event. ¶106 col. 12:44-58

Identified Points of Contention

  • Scope Questions: The case is centered on induced infringement, raising the question of whether the instructions on the Defendants' proposed product labels will direct actions that meet every limitation of the asserted claims. The complaint relies on "information and belief" regarding the label's content, suggesting that the precise wording of the final, FDA-approved label will be a central point of discovery and dispute.
  • Technical Questions: A key technical question will be whether the alleged instructions on the generic labels are specific enough to constitute the claimed methods. For instance, does a general instruction to "adjust the metformin dosage accordingly" Compl. ¶89 satisfy the specific dose-reduction or dose-calculation steps required by the claims of the '547 and '393 patents, respectively? The court will need to determine if there is a mismatch between the general guidance on a drug label and the specific, multi-step protocols defined in the patent claims.

V. Key Claim Terms for Construction

  • The Term: "titration scheme" ('393 Claim 1; '547 Claim 1)

    • Context and Importance: This term is the procedural core of the claimed methods. The infringement case depends on whether the dosing instructions on the Defendants' proposed labels will be found to constitute a "titration scheme." Practitioners may focus on this term because its construction will define the level of procedural detail required for infringement.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification describes the concept generally, such as comprising "the up-titration of the levoketoconazole... until one or more of the following conditions are met: (1) the subject has an adequate response; (2) the highest label-specified dose is reached; or (3) a dose limiting event occurs" '393 Patent, col. 10:59-65 This could support a reading that covers any stepwise dose adjustment process.
      • Evidence for a Narrower Interpretation: The specification also provides highly specific examples, such as a scheme that "comprises administering a first dose... for a first time period; increasing the dose by an amount equal to an incremental value of 150 mg daily; and determining whether the subject tolerates the increased dose" '393 Patent, claim 8 A defendant may argue that the term should be limited to such structured, pre-defined protocols.

  • The Term: "dose limiting event" ('393 Claim 1; '547 Claim 1)

    • Context and Importance: This term acts as the trigger for the monitoring and dose-adjustment steps of the claims. Its definition is critical for determining when the claimed monitoring and subsequent actions are required.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The term itself could be viewed as having a plain and ordinary meaning in the medical field. The claims introduce the term with "wherein," which may be interpreted as defining the event for the purposes of the claim, rather than merely providing examples: "wherein the dose limiting event is a decreased fasting glucose level, abnormal kidney function, and/or a low Vitamin B-12 level" '393 Patent, claim 1
      • Evidence for a Narrower Interpretation: The specification provides specific clinical thresholds for what constitutes these events, such as "abnormal kidney function comprises an estimated glomerular filtration rate (eGFR) of less than 30 mL/min/1.73 m²" '393 Patent, col. 13:36-40 A defendant could argue that a "dose limiting event" only occurs when these specific, objective criteria are met.

VI. Other Allegations

  • Indirect Infringement: The complaint is premised on theories of indirect infringement. It alleges that Defendants will actively induce infringement under 35 U.S.C. § 271(b) by selling their ANDA products with labels that instruct healthcare providers and patients to use the products in a manner that practices the patented methods Compl. ¶99 Compl. ¶117 Compl. ¶135 Compl. ¶153 Knowledge and specific intent are alleged based on Defendants' awareness of the Orange Book-listed patents when filing their ANDAs Compl. ¶97 Compl. ¶115 Contributory infringement under § 271(c) is also alleged, asserting the ANDA products are especially made for an infringing use and are not staple articles of commerce Compl. ¶100 Compl. ¶118
  • Willful Infringement: The complaint alleges that Defendants had "actual and constructive notice" of the Asserted Patents prior to submitting their ANDAs, at least because the patents are listed in the Orange Book for RECORLEV® Compl. ¶97 Compl. ¶98 Compl. ¶115 Compl. ¶116 The allegations that Defendants proceeded with their ANDA submissions despite this knowledge form the basis for claims of willful infringement and a request for this to be deemed an "exceptional case" under 35 U.S.C. § 285 Compl. ¶102 Compl. ¶120

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

  1. A question of induced infringement: The central issue will be evidentiary. Can Plaintiffs prove that the final, FDA-approved labels for the generic products will contain instructions so specific that they direct or encourage physicians to perform every step of the patented methods? The case will likely turn on whether the label's language merely provides general guidance, which may allow for non-infringing uses, or effectively prescribes the patented protocol.

  2. A question of claim construction: The dispute will likely involve a battle over the scope of key terms. Will "titration scheme" be interpreted broadly to cover any stepwise dose adjustment, or will it be narrowly construed to require the specific, multi-step protocols detailed in the patents' embodiments? The outcome of this and other claim construction disputes will be critical in determining whether the defendants' anticipated actions fall within the bounds of the claims.

  3. A question of patentable distinction: The four asserted patents claim very similar methods directed to managing the same drug-drug interaction (levoketoconazole and metformin) through different lenses (e.g., prior surgery, OCT2 vs. MATE1 transporters). A potential issue for the court could be the validity of these patents in light of one another, raising questions of whether the distinctions between them represent non-obvious, patentable inventions or are merely obvious variations of the same core concept.

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