DCT

1:26-cv-00987

Eli Lilly & Co v. Sandoz Inc

Log In
Key Events
Complaint
complaint Intelligence

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: Eli Lilly & Co. v. Sandoz Inc., 1:26-cv-00987, D. Del., 08/06/2026
  • Venue Allegations: Venue is alleged to be proper in the District of Delaware because Defendant Sandoz Inc. is a corporation organized and existing under the laws of Delaware and is therefore considered a resident of the district for venue purposes.
  • Core Dispute: Plaintiff alleges that Defendant's submission of Abbreviated New Drug Applications (ANDAs) to the U.S. Food and Drug Administration (FDA) for approval to market generic versions of Plaintiff's Mounjaro® and Zepbound® products constitutes an act of infringement of ten U.S. patents covering the tirzepatide molecule, pharmaceutical compositions containing it, and methods of its use.
  • Technical Context: The technology relates to tirzepatide, a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor co-agonist, used for glycemic control in type 2 diabetes and for chronic weight management.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Plaintiff's receipt of notice letters from Defendant, which included Paragraph IV certifications asserting that the patents-in-suit are invalid, unenforceable, and/or will not be infringed by the proposed generic products. All asserted patents are listed in the FDA's "Orange Book" for Mounjaro® and/or Zepbound®.

Case Timeline

Date Event
2016-10-25 U.S. Patent No. 9,474,780 Issues
2018-06-22 Earliest Priority Date for '820, '623, '755, '756, and '404 Patents
2018-07-23 Earliest Priority Date for '987, '382, '758, and '740 Patents
2022-05-13 FDA grants approval for Mounjaro® (tirzepatide)
2022-06-14 U.S. Patent No. 11,357,820 Issues
2023-11-08 FDA grants approval for Zepbound® (tirzepatide)
2024-03-05 U.S. Patent No. 11,918,623 Issues
2025-05-13 U.S. Patent No. 12,295,987 Issues
2025-07-01 U.S. Patent No. 12,343,382 Issues
2025-10-28 U.S. Patent No. 12,453,755 Issues
2025-10-28 U.S. Patent No. 12,453,756 Issues
2025-10-28 U.S. Patent No. 12,453,758 Issues
2026-05-05 U.S. Patent No. 12,616,740 Issues
2026-05-19 U.S. Patent No. 12,629,404 Issues
2026-06-29 Date of first Sandoz Notice Letter
2026-07-15 Date of second Sandoz Notice Letter
2026-08-06 Complaint Filing Date

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

U.S. Patent No. 9,474,780 - "GIP and GLP-1 Co-agonist Compounds"

  • Patent Identification: U.S. Patent No. 9,474,780, titled "GIP and GLP-1 Co-agonist Compounds," issued October 25, 2016.

The Invention Explained

  • Problem Addressed: The complaint does not detail the problem described in the patent's background but asserts the patent covers compounds useful for treating type 2 diabetes mellitus (T2D) Compl. ¶1
  • The Patented Solution: The patent claims specific peptide compounds that act as co-agonists for both the GIP and GLP-1 receptors Compl. ¶20 Compl. ¶50 These compounds are chemically modified peptides designed to treat T2D. Claim 1 defines a specific peptide formula with modifications, including a fatty acid moiety intended to extend the compound's duration of action Compl. ¶50
  • Technical Importance: Dual-agonist peptides that activate both GIP and GLP-1 receptors represent a therapeutic approach for managing T2D and obesity, aiming for greater efficacy than agents targeting only one of these pathways Compl. ¶16

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 Compl. ¶51
  • Claim 1 recites a compound with the following essential elements:
    • A specific 39-amino acid peptide sequence: YX₁EGTFTSDYSIX₂LDKIAQKAX₃VQWLIAGGPSSGAPPPS, where X₁ and X₂ are Aib Compl. ¶50
    • A chemical modification at the lysine (K) at position 20, conjugated to a specific fatty diacid-containing moiety Compl. ¶50
    • A specified variable (X₃) at position 22, which is Phe or 1-Nal Compl. ¶50
    • An optional amidation of the C-terminal amino acid Compl. ¶50
    • Or a pharmaceutically acceptable salt thereof Compl. ¶50

U.S. Patent No. 11,357,820 - "GIP/GLP1 Agonist Compositions"

  • Patent Identification: U.S. Patent No. 11,357,820, titled "GIP/GLP1 Agonist Compositions," issued June 14, 2022.

The Invention Explained

  • Problem Addressed: The patent describes a need for pharmaceutical compositions of the GIP/GLP1 co-agonist peptide tirzepatide that provide acceptable stability and an acceptable patient injection site experience, noting that some common formulation components like NaCl can be associated with painful stinging at the injection site '820 Patent, col. 1:21-25 '820 Patent, col. 4:8-24
  • The Patented Solution: The patent discloses a pharmaceutical composition for subcutaneous injection that includes tirzepatide, NaCl as a tonicity agent, and dibasic sodium phosphate '820 Patent, abstract '820 Patent, col. 1:26-30 This combination is described as providing commercially acceptable shelf-life stability and in-use stability while being associated with an acceptable patient injection site experience '820 Patent, col. 1:28-30 '820 Patent, col. 4:26-30
  • Technical Importance: Developing stable, injectable peptide formulations that are well-tolerated by patients is critical for the commercial success and patient compliance of chronic therapies like those for diabetes and obesity.

Key Claims at a Glance

  • The complaint asserts infringement of at least independent claim 1 Compl. ¶68
  • Claim 1 recites a composition with the following essential elements:
    • A pharmaceutical composition comprising tirzepatide, or a pharmaceutically acceptable salt thereof '820 Patent, col. 9:40-42
    • NaCl at a concentration from 6.2 mg/mL to 9.5 mg/mL '820 Patent, col. 9:42-43
    • dibasic sodium phosphate '820 Patent, col. 9:44

U.S. Patent No. 11,918,623 - "GIP/GLP1 Agonist Compositions"

  • Patent Identification: U.S. Patent No. 11,918,623, titled "GIP/GLP1 Agonist Compositions," issued March 5, 2024 Compl. ¶24
  • Technology Synopsis: The patent claims a method of treating obesity by administering a pharmaceutical composition containing tirzepatide within specific concentration ranges for its active ingredient and excipients, including dibasic sodium phosphate, NaCl, and optionally phenol '623 Patent, col. 9:40-50
  • Asserted Claims: At least independent claim 1 is asserted Compl. ¶85
  • Accused Features: The accused product, through its proposed labeling, is alleged to instruct and encourage treating obesity using a composition that meets the claimed concentration parameters Compl. ¶85

U.S. Patent No. 12,295,987 - "Methods of Using a GIP/GLP1 Co-agonist for Diabetes"

  • Patent Identification: U.S. Patent No. 12,295,987, titled "Methods of Using a GIP/GLP1 Co-agonist for Diabetes," issued May 13, 2025 Compl. ¶26
  • Technology Synopsis: The patent claims a specific dose-escalation method for treating type 2 diabetes. The method involves administering four sequential doses of a GIP:GLP-1 peptide, with the first three doses being specific percentages (25%, 50%, 75%) of the fourth dose '987 Patent, col. 10:25-45
  • Asserted Claims: At least independent claim 1 is asserted Compl. ¶104
  • Accused Features: The proposed labeling for the accused product is alleged to instruct and encourage the claimed four-step dose-escalation regimen for treating type 2 diabetes Compl. ¶104

U.S. Patent No. 12,343,382 - "Methods of Using a GIP/GLP1 Co-agonist for Therapy"

  • Patent Identification: U.S. Patent No. 12,343,382, titled "Methods of Using a GIP/GLP1 Co-agonist for Therapy," issued July 1, 2025 Compl. ¶28
  • Technology Synopsis: The patent claims methods of treating type 2 diabetes and improving weight management through a dose-escalation regimen. The method involves administering an "escalation dose" from one group of specified amounts and a "maintenance dose" from a second group of specified amounts '382 Patent, col. 63:1-13 '382 Patent, col. 63:23-35
  • Asserted Claims: At least independent claims 1 and 11 are asserted Compl. ¶¶123-125
  • Accused Features: The proposed labeling for the accused products is alleged to instruct and encourage the claimed methods of administering escalation and maintenance doses of tirzepatide for treating T2D and improving weight management Compl. ¶¶123-125

U.S. Patent No. 12,453,755 - "GIP/GLP1 Agonist Compositions"

  • Patent Identification: U.S. Patent No. 12,453,755, titled "GIP/GLP1 Agonist Compositions," issued October 28, 2025 Compl. ¶30
  • Technology Synopsis: The patent claims a method of treating diabetes by administering a pharmaceutical composition containing tirzepatide, dibasic sodium phosphate, NaCl, and optionally phenol, all within specified concentration ranges '755 Patent, col. 9:41-51
  • Asserted Claims: At least independent claim 1 is asserted Compl. ¶146
  • Accused Features: The proposed labeling for the accused product is alleged to instruct and encourage treating diabetes with a composition that meets the claimed parameters Compl. ¶146

U.S. Patent No. 12,453,756 - "GIP/GLP1 Agonist Compositions"

  • Patent Identification: U.S. Patent No. 12,453,756, titled "GIP/GLP1 Agonist Compositions," issued October 28, 2025 Compl. ¶32
  • Technology Synopsis: The patent claims a pharmaceutical composition comprising tirzepatide and a specific concentration range of NaCl, where the composition has a pH between 6.5 and 7.5 '756 Patent, col. 9:43-49
  • Asserted Claims: At least independent claim 1 is asserted Compl. ¶165
  • Accused Features: The accused products are alleged to be pharmaceutical compositions that meet the claim's requirements for tirzepatide, NaCl concentration, and pH range Compl. ¶165

U.S. Patent No. 12,453,758 - "Methods of Using a GIP/GLP1 Co-agonist for Diabetes"

  • Patent Identification: U.S. Patent No. 12,453,758, titled "Methods of Using a GIP/GLP1 Co-agonist for Diabetes," issued October 28, 2025 Compl. ¶34
  • Technology Synopsis: The patent claims a method for improving weight management using a specific four-step dose-escalation regimen of a GIP:GLP-1 peptide, where the first three doses are 25%, 50%, and 75% of the fourth dose, respectively '758 Patent, col. 67:35-51
  • Asserted Claims: At least independent claim 1 is asserted Compl. ¶182
  • Accused Features: The proposed product labeling is alleged to instruct the claimed dose-escalation method for improving weight management Compl. ¶182

U.S. Patent No. 12,616,740 - "Methods of Using a GIP/GLP1 Co-agonist for Therapy"

  • Patent Identification: U.S. Patent No. 12,616,740, titled "Methods of Using a GIP/GLP1 Co-agonist for Therapy," issued May 5, 2026 Compl. ¶36
  • Technology Synopsis: The patent claims methods of treating type 2 diabetes and obesity by administering tirzepatide in a specific dose-escalation schedule: a first dose of 2.5 mg for four weeks, followed by 2.5 mg increments to a maintenance dose of 5, 10, or 15 mg, with each increased dose administered for at least four weeks '740 Patent, col. 63:6-21 '740 Patent, col. 63:25-40
  • Asserted Claims: At least independent claims 1 and 6 are asserted Compl. ¶201 Compl. ¶203
  • Accused Features: The proposed labeling for the accused products is alleged to instruct the claimed dose-escalation regimens for treating T2D and obesity Compl. ¶201 Compl. ¶203

U.S. Patent No. 12,629,404 - "GIP/GLP1 Agonist Compositions"

  • Patent Identification: U.S. Patent No. 12,629,404, titled "GIP/GLP1 Agonist Compositions," issued May 19, 2026 Compl. ¶38
  • Technology Synopsis: The patent claims a preservative-free pharmaceutical composition containing tirzepatide, a specific concentration range of NaCl, and having a pH between 6.5 and 7.5 '404 Patent, col. 9:43-50
  • Asserted Claims: At least independent claim 1 is asserted Compl. ¶224
  • Accused Features: The accused products are alleged to be compositions that meet the claim's requirements for being preservative-free and having the specified tirzepatide, NaCl concentration, and pH parameters Compl. ¶224

III. The Accused Instrumentality

Product Identification

  • Defendant Sandoz's Proposed ANDA Products, identified as generic versions of Mounjaro® (tirzepatide) and Zepbound® (tirzepatide) in various strength autoinjectors Compl. ¶1 Specifically, the complaint references ANDA Nos. 218833 and 221376 Compl. ¶1

Functionality and Market Context

  • The accused products are injectable drug products containing tirzepatide as the active pharmaceutical ingredient Compl. ¶44 They are intended for subcutaneous use to improve glycemic control, treat obesity, and manage weight, mirroring the indications for Lilly's Mounjaro® and Zepbound® products Compl. ¶1 Compl. ¶¶85, 104, 123-125
  • The complaint alleges that the proposed ANDA products will be marketed as competing products to Mounjaro® and Zepbound® upon FDA approval Compl. ¶1 Sandoz's ANDA filings assert that its products are bioequivalent to Lilly's branded products or seek a waiver of that requirement Compl. ¶45 The complaint includes a visual depicting the chemical structure of tirzepatide, the active ingredient in both the branded and accused generic products Compl. ¶51

IV. Analysis of Infringement Allegations

'780 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A compound of Formula: YX₁EGTFTSDYSIX₂LDKIAQKAX₃VQWLIAGGPSSGAPPPS...or a pharmaceutically acceptable salt thereof. Sandoz's Proposed ANDA Products contain tirzepatide, which is alleged to be a compound with the structural formula corresponding to the claim. ¶51 Patent document not provided

'820 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A pharmaceutical composition comprising tirzepatide, or a pharmaceutically acceptable salt thereof; Sandoz's Proposed ANDA Products are alleged to be pharmaceutical compositions comprising tirzepatide. ¶68 col. 1:26-30
NaCl at a concentration from 6.2 mg/mL to 9.5 mg/mL; Sandoz's Proposed ANDA Products are alleged to contain NaCl at a concentration within the claimed range. ¶68 col. 1:31-32
and dibasic sodium phosphate. Sandoz's Proposed ANDA Products are alleged to contain dibasic sodium phosphate. ¶68 col. 1:41-45
  • Identified Points of Contention:
    • Scope Questions: The complaint alleges that Sandoz's notice letters do not contest that the asserted patents "cover" the Proposed ANDA Products Compl. ¶54 Compl. ¶71 Compl. ¶88 Compl. ¶107 This suggests the primary dispute may not be over the technical scope of the claims but rather their validity or enforceability. A central question for the court will be whether Sandoz's Paragraph IV certification of non-infringement, invalidity, and/or unenforceability has merit Compl. ¶41
    • Technical Questions: For the formulation patents (e.g., the '820 Patent), a latent technical question is whether the excipients in Sandoz's formulation, such as "dibasic sodium phosphate," are identical in form and function to those contemplated by the patent. For the method-of-use patents (e.g., the '382 patent), an evidentiary question will be whether the instructions on Sandoz's proposed product labels will, in practice, induce physicians and patients to perform the claimed dose-escalation methods.

V. Key Claim Terms for Construction

  • The Term: "dibasic sodium phosphate" (from claim 1 of the '820 Patent)
  • Context and Importance: This term is a required excipient in the claimed formulation. The construction of this term is important because it could determine whether Sandoz's specific formulation, if it uses a different form or hydrate of sodium phosphate, falls within the literal scope of the claim. Practitioners may focus on this term to determine if there is a literal infringement mismatch or a need to argue under the doctrine of equivalents.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language itself simply recites "dibasic sodium phosphate" without specifying a particular hydrate, salt form, or function '820 Patent, col. 9:44 This may support an interpretation that the mere presence of the chemical, in any of its common forms, satisfies the limitation.
    • Evidence for a Narrower Interpretation: The specification refers to the use of a "phosphate buffer" and adjusting pH, suggesting a potential functional requirement for the term '820 Patent, col. 4:32-36 Furthermore, the complaint, in describing Lilly's own product, identifies the excipient as "sodium phosphate dibasic heptahydrate" Compl. ¶17 A party could argue that this specific embodiment narrows the scope of the broader term used in the claims.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all asserted patents. Inducement is based on allegations that Sandoz's proposed product labeling will instruct and encourage physicians and patients to use the products in an infringing manner, constituting the patented methods of treatment (Compl. ¶60; Compl. ¶77; Compl. ¶94; Compl. ¶113). Contributory infringement is based on allegations that the accused products are especially made for an infringing use and are not suitable for a substantial noninfringing use (Compl. ¶61; Compl. ¶78; Compl. ¶97; Compl. ¶116).
  • Willful Infringement: The complaint does not use the term "willful infringement" in its counts for relief. However, it lays a foundation for potential enhanced damages by pleading that Sandoz had pre-suit knowledge of the asserted patents. This knowledge is alleged to arise from the patents' listing in the FDA's Orange Book and from Sandoz's inclusion of the patents in its notice letters to Lilly (Compl. ¶59; Compl. ¶76; Compl. ¶93; Compl. ¶112).

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

  • A central issue for the litigation will be one of patent validity. Given that the complaint alleges Sandoz does not contest that its products are covered by the claims, the case will likely focus on Sandoz's defenses that the patents are invalid as obvious or anticipated by the prior art, or are otherwise unenforceable.
  • A second key question will concern infringement of the method claims. This will be an evidentiary issue focused on whether the instructions for use on Sandoz's proposed product labels are sufficient to establish that Sandoz will induce infringement of the specific dose-escalation and treatment regimens recited in patents such as the '987, '382, '758, and '740 patents.
  • A final question relates to the scope of the formulation claims. For patents like the '820 and '756, a point of contention may arise over whether the specific excipients and concentration ranges in Sandoz's ANDA products fall within the literal scope of the claims or, if not, whether they infringe under the doctrine of equivalents.
Loading Complaint