DCT

1:26-cv-00541

Array Biopharma Inc v. Zydus Lifesciences Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:26-cv-00541, D. Del., 05/08/2026
  • Venue Allegations: Plaintiffs allege venue is proper in the District of Delaware because Defendants include foreign corporations subject to personal jurisdiction in the district and because all Defendants regularly engage in patent litigation in the district.
  • Core Dispute: Plaintiffs allege that Defendants' submission of an Abbreviated New Drug Application (ANDA) to the U.S. Food and Drug Administration for generic larotrectinib sulfate capsules constitutes an act of infringement of five U.S. patents covering the branded drug VITRAKVI®.
  • Technical Context: The technology relates to a specific crystalline form of larotrectinib sulfate, a tropomyosin receptor kinase (TRK) inhibitor used to treat solid tumors characterized by neurotrophic receptor tyrosine kinase (NTRK) gene fusions.
  • Key Procedural History: The litigation was initiated under the Hatch-Waxman Act following a March 26, 2026 notification letter from Zydus informing Plaintiffs of its ANDA filing. The patents-in-suit are listed in the FDA's Orange Book in connection with New Drug Application No. 210861 for VITRAKVI®.

Case Timeline

Date Event
2014-11-16 Earliest Priority Date for '414, '861, '993, '505, '936 Patents
2017-10-10 U.S. Patent No. 9,782,414 Issued
2019-01-08 U.S. Patent No. 10,172,861 Issued
2019-05-14 U.S. Patent No. 10,285,993 Issued
2020-10-13 U.S. Patent No. 10,799,505 Issued
2020-10-27 U.S. Patent No. 10,813,936 Issued
2026-03-26 Zydus sends Notice Letter to Plaintiffs regarding ANDA submission
2026-05-08 Complaint Filed

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

U.S. Patent No. 9,782,414 - "Crystalline form of (S)-N-(5-((R)-2-(2,5-difluorophenyl)-pyrrolidin-1-yl)-pyrazolo[1,5-A]pyrimidin-3-yl)-3-hydroxypyrrolidine-1-carboxamide hydrogen sulfate"

Issued October 10, 2017.

The Invention Explained

  • Problem Addressed: The patent background describes that overexpression, activation, amplification, and/or mutation of Tropomyosin receptor kinases (Trk's) are associated with numerous cancers, creating a need for effective Trk inhibitors to treat such conditions '861 Patent, col. 1:44-col. 2:6
  • The Patented Solution: The invention is a specific, stable crystalline form (polymorph) of the hydrogen sulfate salt of the Trk-inhibiting compound larotrectinib, designated as crystalline form (I-HS) '861 Patent, col. 4:47-54 This specific solid-state form is characterized by a unique X-ray powder diffraction pattern, which provides consistency and stability for use in a pharmaceutical product '861 Patent, abstract
  • Technical Importance: The development of a stable and reproducible crystalline form of an active pharmaceutical ingredient is critical for consistent manufacturing, formulation, bioavailability, and shelf-life, which are essential for commercial and therapeutic viability '861 Patent, col. 16:32-42

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 21 Compl. ¶59
  • Essential elements of independent claim 1:
    • A method of treating cancer in a pediatric patient in need thereof;
    • The method comprises detecting a cancer in the patient that exhibits a dysregulation of a NTRK gene, a Trk protein, or expression or level of the same; and
    • Administering a therapeutically effective amount of a dosage form comprising a crystalline form (I-HS) of larotrectinib sulfate;
    • Wherein the crystalline form is defined by an X-ray powder diffraction pattern with peaks at °20 values of 18.4±0.2, 20.7±0.2, 23.1±0.2, and 24.0±0.2 Compl. ¶54
  • Essential elements of independent claim 21 are similar to claim 1 but frame the method as treating a cancer that exhibits the dysregulation, comprising the step of administering the dosage form to a pediatric patient Compl. ¶55
  • The complaint alleges infringement of one or more claims of the '414 Patent, including at least claims 1 and 21 Compl. ¶63

U.S. Patent No. 10,172,861 - "Crystalline form of (S)-N-(5-((R)-2-(2,5-difluorophenyl)-pyrrolidin-1-yl)-pyrazolo[1,5-A]pyrimidin-3-yl)-3-hydroxypyrrolidine-1-carboxamide hydrogen sulfate"

Issued January 8, 2019.

The Invention Explained

  • Problem Addressed: As described for the '414 Patent, the background of the '861 Patent addresses the role of Trk kinases in various cancers and the need for inhibitors to treat them '861 Patent, col. 1:44-col. 2:6
  • The Patented Solution: The invention is the composition of matter for the specific crystalline polymorph, Form (I-HS), of larotrectinib hydrogen sulfate. The patent describes this form as a stable polymorph suitable for pharmaceutical use and characterizes it by its distinct X-ray powder diffraction pattern '861 Patent, abstract '861 Patent, col. 4:47-54
  • Technical Importance: As with the '414 Patent, identifying and claiming a specific, stable crystalline form of a drug is a critical step in pharmaceutical development to ensure product consistency and quality '861 Patent, col. 16:32-42

Key Claims at a Glance

  • The complaint asserts independent claim 1 Compl. ¶76
  • Essential elements of independent claim 1:
    • A crystalline form (I-HS) having the specified chemical formula for larotrectinib sulfate;
    • Wherein the crystalline form is characterized by an X-ray powder diffraction (XRPD) pattern comprising peaks at °20 values of 18.4±0.2, 20.7±0.2, 23.1±0.2, and 24.0±0.2 Compl. ¶76
  • The complaint alleges infringement of one or more claims, including at least claim 1 Compl. ¶84

U.S. Patent No. 10,285,993 - "Crystalline form of (S)-N-(5-((R)-2-(2,5-difluorophenyl)-pyrrolidin-1-yl)-pyrazolo[1,5-a]pyrimidin-3-yl)-3-hydroxypyrrolidine-1-carboxamide hydrogen sulfate"

Issued May 14, 2019 Compl. ¶95

  • Technology Synopsis: The patent claims a method of treating cancer mediated by a Trk kinase by administering a therapeutically effective amount of the same crystalline form (I-HS) of larotrectinib sulfate at issue in the '414 and '861 patents '993 Patent, abstract The crystalline form is identified by the same characteristic XRPD diffraction peaks Compl. ¶97
  • Asserted Claims: The complaint asserts at least claim 1 Compl. ¶100
  • Accused Features: The accused feature is the use of Zydus's ANDA Product (larotrectinib sulfate capsules) in accordance with its proposed labeling to treat Trk-mediated cancer Compl. ¶100 Compl. ¶101

U.S. Patent No. 10,799,505 - "Crystalline form of (S)-N-(5-((R)-2-(2,5-difluorophenyl)-pyrrolidin-1-yl)-pyrazolo[1,5-A]pyrimidin-3-yl)-3-hydroxypyrrolidine-1-carboxamide hydrogen sulfate"

Issued October 13, 2020 Compl. ¶116

  • Technology Synopsis: The patent claims the crystalline form (I-HS) of larotrectinib sulfate, adding a negative limitation that the crystalline form is "substantially free of the amorphous form" '505 Patent, abstract Compl. ¶118 This claim focuses on the purity of the specific polymorph relative to its non-crystalline counterpart.
  • Asserted Claims: The complaint asserts at least claim 1 Compl. ¶121
  • Accused Features: The accused feature is Zydus's ANDA Product itself, which is alleged to be a crystalline form of larotrectinib sulfate that is substantially free of the amorphous form Compl. ¶121

U.S. Patent No. 10,813,936 - "Crystalline form of (S)-N-(5-((R)-2-(2,5-difluorophenyl)-pyrrolidin-1-yl)-pyrazolo[1,5-a]pyrimidin-3-yl)-3-hydroxypyrrolidine-1-carboxamide hydrogen sulfate"

Issued October 27, 2020 Compl. ¶137

  • Technology Synopsis: The patent claims a method for treating a specific subset of cancers (lung cancer, undifferentiated sarcoma, acute myeloid leukemia, and colorectal cancer) that exhibit particular chromosomal translocations or inversions resulting in NTRK1, NTRK2, or NTRK3 gene fusions '936 Patent, abstract The treatment comprises administering the same crystalline form (I-HS) of larotrectinib sulfate Compl. ¶139
  • Asserted Claims: The complaint asserts at least claim 1 Compl. ¶142
  • Accused Features: The accused feature is the use of Zydus's ANDA Product in accordance with its proposed labeling for treating the specified cancers with the requisite genetic markers Compl. ¶142 Compl. ¶143

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are "Zydus's ANDA Products," identified as larotrectinib sulfate capsules, 25 mg and 100 mg, for which Zydus submitted ANDA No. 220875 to the FDA Compl. ¶2 Compl. ¶3

Functionality and Market Context

  • The accused products are generic versions of Plaintiffs' VITRAKVI® (larotrectinib sulfate) capsules Compl. ¶9 Compl. ¶18 Larotrectinib is a tropomyosin receptor kinase (TRK) inhibitor used to treat adult and pediatric patients with solid tumors that have a neurotrophic receptor tyrosine kinase (NTRK) gene fusion Compl. ¶47
  • The complaint provides the chemical structure for larotrectinib sulfate, the active ingredient in VITRAKVI® and the accused generic product Compl. ¶49
  • The complaint alleges that Zydus submitted its ANDA to obtain FDA approval for commercial manufacture, use, and sale of its generic products prior to the expiration of the Patents-in-Suit Compl. ¶2

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,782,414 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of treating cancer in a pediatric patient in need thereof, the method comprising: Zydus's proposed labeling for its ANDA Product allegedly directs or encourages the treatment of cancer in pediatric patients. ¶59 col. 2:3-6
a) detecting a cancer in a pediatric patient that exhibits a dysregulation of a NTRK gene, a Trk protein, or expression or level of the same; and The proposed labeling for Zydus's ANDA Product allegedly instructs that the product be used in patients whose cancer exhibits the claimed dysregulation. ¶59 col. 2:7-13
b) administering to the pediatric patient a therapeutically effective amount of a dosage form comprising a crystalline form (I-HS) having the formula... Zydus's ANDA Product is a capsule containing larotrectinib sulfate, which Plaintiffs allege is the claimed crystalline form (I-HS). ¶58 col. 4:47-54
wherein the crystalline form has an X-ray powder diffraction pattern comprising peaks at °20 values of 18.4±0.2, 20.7±0.2, 23.1±0.2, and 24.0±0.2. The larotrectinib sulfate in Zydus's ANDA Product is alleged to be the specific crystalline form (I-HS) characterized by the claimed XRPD peaks. ¶58 col. 5:1-4

U.S. Patent No. 10,172,861 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A crystalline form (I-HS) having the formula... Zydus's ANDA Product is a capsule containing larotrectinib sulfate, which is alleged to be the claimed crystalline form (I-HS). ¶79 col. 4:47-54
wherein the crystalline form is characterized by having an X-ray powder diffraction (XRPD) pattern comprising peaks at °20 values of 18.4±0.2, 20.7±0.2, 23.1±0.2, and 24.0±0.2. The larotrectinib sulfate in Zydus's ANDA Product is alleged to have the specific XRPD pattern recited in the claim. ¶79 col. 5:1-4

Identified Points of Contention

  • Polymorphic Form: A central technical question may be whether the larotrectinib sulfate in Zydus's ANDA Products is, in fact, the specific crystalline form (I-HS) claimed in the patents. The claims define this polymorph by a set of characteristic peaks in an X-ray powder diffraction pattern. The case may turn on evidence comparing the XRPD pattern of Zydus's product to the claimed pattern. However, the complaint alleges that Zydus's Notice Letter "did not contest the infringement of claims 1-10 and 21-25 of the '414 patent" and "claims 1-9 of the '861 patent," which raises the question of whether infringement will be a primary point of dispute or if the case will focus on patent validity Compl. ¶60 Compl. ¶81
  • Induced Infringement: For the method-of-use claims (e.g., in the '414, '993, and '936 Patents), a legal question will be whether Zydus's proposed product labeling provides sufficient instruction and encouragement to healthcare providers and patients to perform all the claimed steps. This includes not only administering the drug but also, for some claims, the step of "detecting" the specific cancer markers required for treatment Compl. ¶54

V. Key Claim Terms for Construction

  • The Term: "a crystalline form... characterized by having an X-ray powder diffraction (XRPD) pattern comprising peaks at °20 values of 18.4±0.2, 20.7±0.2, 23.1±0.2, and 24.0±0.2" (from '861 Patent, claim 1).
  • Context and Importance: This phrase is the structural definition of the patented polymorph. The infringement analysis for all five patents hinges on whether Zydus's product meets this definition. Practitioners may focus on whether the term "comprising" requires only the presence of these four peaks or if the overall pattern must substantially match what is disclosed in the patent.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The use of the open-ended term "comprising" suggests that the XRPD pattern of an infringing product must include these four peaks but may also contain others. The patent specification discloses a table with over twenty characteristic peaks for Form I-HS, suggesting the four peaks in the independent claim are a subset chosen to characterize, but not exhaustively define, the form '861 Patent, Table 1, col. 11-12
    • Evidence for a Narrower Interpretation: A party might argue that to distinguish the patented polymorph from other potential crystalline or amorphous forms, the "characterization" requires a more holistic match to the XRPD pattern disclosed in the patent's figures (e.g., '861 Patent, FIG. 1 or FIG. 29). The patent also provides other characterization data, such as a differential scanning calorimetry (DSC) profile, which could be argued as integral to the definition of the specific crystalline form '861 Patent, col. 5:19-24

VI. Other Allegations

  • Indirect Infringement: The complaint alleges active inducement and contributory infringement of the method-of-use patents ('414, '993, and '936 patents). The basis for these allegations is that Zydus knows its ANDA Product and its proposed labeling are especially adapted for infringing use and not suitable for substantial non-infringing use, and that Zydus intends for infringement to occur upon FDA approval, as directed by the product's labeling Compl. ¶¶64-65 Compl. ¶¶106-107 Compl. ¶¶148-149
  • Willful Infringement: The complaint does not use the term "willful." However, it alleges that Zydus possesses knowledge of the patents-in-suit (based on the ANDA certification and Notice Letter) and has "continued to assert its intent to manufacture, offer for sale, sell, distribute, and/or import" its product prior to patent expiration Compl. ¶66 Compl. ¶87 Plaintiffs also request a declaration that this is an "exceptional case" and seek an award of attorneys' fees pursuant to 35 U.S.C. § 285, a remedy often associated with findings of willful infringement or litigation misconduct Compl. ¶156(e)

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

  • A core issue will be one of polymorphic identity: Given that Zydus allegedly did not contest infringement in its notification letter for many asserted claims, the central question for the court may shift from whether Zydus's product infringes to one of validity. However, should infringement be contested, the case will turn on factual evidence of whether Zydus's generic product is the specific crystalline form "I-HS" as defined by the characteristic X-ray powder diffraction peaks recited in the claims.
  • A key evidentiary question for the method claims will be one of inducement: Does the language of the proposed label for Zydus's ANDA product actively encourage or instruct medical professionals to perform every step of the claimed methods, including the diagnostic prerequisite of detecting a dysregulation of an NTRK gene as required by Claim 1 of the '414 patent?
  • A potential question of claim scope will arise for the '505 Patent: What is the proper construction of the term "substantially free of the amorphous form," and what quantum of evidence is necessary to establish that the accused generic product satisfies this negative limitation regarding its purity?
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