3:26-cv-09635
Astellas Pharma Inc v. Macleods Pharma Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Astellas Pharma Inc. (Japan); Astellas US LLC (Delaware); Astellas Pharma US, Inc. (Delaware); Medivation LLC (Delaware); Medivation Prostate Therapeutics LLC (Delaware)
- Defendant: Macleods Pharmaceuticals Ltd. (India); Macleods Pharma USA, Inc. (Delaware)
- Plaintiff's Counsel: Walsh Pizzi Oreilly Falanga LLP
- Case Identification: 3:26-cv-09635, D.N.J., 07/30/2026
- Venue Allegations: Venue is alleged to be proper in the District of New Jersey because Defendant Macleods Pharma USA, Inc. maintains its principal place of business in Princeton, New Jersey. Venue is asserted over Defendant Macleods Pharmaceuticals Ltd. on the basis that it is a foreign corporation that may be sued in any judicial district.
- Core Dispute: This is a patent infringement action under the Hatch-Waxman Act in which Plaintiffs allege that Defendants' filing of an Abbreviated New Drug Application (ANDA) to market generic versions of Plaintiffs' Xtandi® (enzalutamide) tablets constitutes infringement of four U.S. patents.
- Technical Context: The technology concerns pharmaceutical formulations of enzalutamide, an androgen receptor inhibitor used for treating prostate cancer, and methods of its use, including specific dosing regimens to manage drug-drug interactions.
- Key Procedural History: The action was triggered by a notice letter dated June 15, 2026, in which Defendants informed Plaintiffs of their filing of ANDA No. 221507 with the U.S. Food and Drug Administration (FDA), seeking approval to market generic enzalutamide tablets. The notice letter included a certification asserting that the patents-in-suit are invalid, unenforceable, and/or not infringed. The complaint notes a related, pending case in the same district, Astellas Pharma Inc v. DR Reddy's Laboratories Inc et al.
Case Timeline
| Date | Event |
|---|---|
| 2012-09-11 | Priority Date for '689, '357, and '128 Patents |
| 2015-08-12 | Priority Date for '628 Patent |
| 2016-09-28 | Pfizer Inc. acquires Medivation, Inc. |
| 2020-08-04 | FDA approves NDA for Xtandi® (enzalutamide) tablets |
| 2023-11-16 | FDA approves expanded indication for Xtandi® tablets |
| 2023-12-12 | Issue Date for U.S. Patent No. 11,839,689 |
| 2024-12-10 | Issue Date for U.S. Patent No. 12,161,628 |
| 2025-10-21 | Issue Date for U.S. Patent No. 12,447,128 |
| 2025-12-23 | Issue Date for U.S. Patent No. 12,502,357 |
| 2026-06-15 | Date of Macleods' Notice Letter to Plaintiffs |
| 2026-07-30 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 11,839,689 - "Formulations of Enzalutamide"
The Invention Explained
- Problem Addressed: The patent addresses the poor aqueous solubility of the active pharmaceutical ingredient enzalutamide, a property that can limit its absorption and oral bioavailability when formulated in a conventional solid dosage form '689 Patent, col. 2:25-31
- The Patented Solution: The invention is a pharmaceutical composition that stabilizes enzalutamide in its more soluble, non-crystalline (amorphous) state '689 Patent, col. 2:50-54 This is achieved by creating a "solid dispersion" where amorphous enzalutamide is dispersed within a concentration-enhancing polymer, specifically hydroxypropyl methylcellulose acetate succinate (HPMCAS) '689 Patent, abstract '689 Patent, col. 3:46-49 This formulation is designed to dissolve more quickly and achieve higher drug concentrations in the body compared to crystalline enzalutamide '689 Patent, col. 2:55-63 The complaint provides the chemical structure of enzalutamide Compl. p. 7
- Technical Importance: This technology enables the creation of a solid oral tablet formulation for enzalutamide that provides sufficient bioavailability, potentially offering a more convenient alternative to liquid-filled capsules for patients.
Key Claims at a Glance
- The complaint asserts infringement of, at a minimum, Claim 1 Compl. ¶52
- Claim 1 of the '689 Patent recites:
- A pharmaceutical composition comprising a solid dispersion
- consisting essentially of amorphous enzalutamide
- and hydroxypropyl methylcellulose acetate succinate ("HPMCAS").
- The complaint notes that certain dependent claims specify that the formulation is a tablet Compl. ¶52
U.S. Patent No. 12,161,628 - "Combination Therapy"
The Invention Explained
- Problem Addressed: The patent addresses a specific drug-drug interaction. Enzalutamide is metabolized in the body by enzymes, including CYP3A4 '628 Patent, col. 2:1-5 When co-administered with a strong "inducer" of this enzyme, such as the antibiotic rifampin, the metabolism of enzalutamide is accelerated, leading to lower-than-intended drug concentrations in the patient's plasma and potentially reducing its therapeutic effect '628 Patent, col. 2:5-14
- The Patented Solution: The patent provides a specific method to counteract this interaction. It claims a method of treating prostate cancer in a patient who is also taking rifampin, which involves "co-administering to the patient a daily dose of 240 mg of enzalutamide" '628 Patent, claim 1 This represents an increased dose from the standard 160 mg daily dose, intended to compensate for the accelerated metabolism caused by rifampin.
- Technical Importance: This invention provides a clinically applicable dosing strategy to maintain the efficacy of enzalutamide in patients who must concurrently take rifampin or other strong CYP3A4 inducers for other medical conditions.
Key Claims at a Glance
- The complaint asserts infringement of, at a minimum, Claim 1 Compl. ¶67
- Claim 1 of the '628 Patent recites:
- A method of treating prostate cancer in a patient
- to whom rifampin is administered,
- comprising co-administering to the patient a daily dose of 240 mg of enzalutamide.
U.S. Patent No. 12,502,357 - "Formulations of Enzalutamide"
Technology Synopsis
The patent claims a method of treating prostate cancer by administering a specific tablet formulation. The technology is similar to the '689 Patent, focusing on a solid dispersion of amorphous enzalutamide with HPMCAS to improve solubility and bioavailability Compl. ¶80
Asserted Claims
The complaint asserts infringement of, at a minimum, Claim 1 Compl. ¶80
Accused Features
The accused features are the manufacture and sale of Macleods' generic enzalutamide tablets and the instructions in its proposed product labeling that will allegedly direct physicians to administer these tablets for treating prostate cancer Compl. ¶¶83-84 Compl. ¶87
U.S. Patent No. 12,447,128 - "Formulations of Enzalutamide"
Technology Synopsis
This patent claims a method of treating prostate cancer by orally administering two 80 mg tablets. The claim recites a specific composition for each tablet (a spray-dried dispersion of 80 mg amorphous enzalutamide and 400 mg HPMCAS) and includes a functional limitation related to the stability of the amorphous form under specific heat and humidity conditions Compl. ¶99
Asserted Claims
The complaint asserts infringement of, at a minimum, Claim 3 Compl. ¶99
Accused Features
The accused features are Macleods' 80 mg generic products, which are alleged to be tablets containing the claimed spray-dried dispersion and meeting the claimed stability requirement. The infringement allegation also covers the instructions in the proposed product labeling that will direct this use Compl. ¶¶102-103 Compl. ¶106
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are the "Macleods' Generic Products," which are enzalutamide tablets in 40 mg and 80 mg dosages for which Macleods is seeking FDA approval via ANDA No. 221507 Compl. ¶¶40-41
Functionality and Market Context
The complaint alleges that these generic products are intended to be generic versions of Plaintiffs' Xtandi® tablets Compl. ¶41 They are designed to contain the active ingredient enzalutamide and are intended to be sold for the same indications as Xtandi®, including the treatment of castration-resistant prostate cancer, metastatic castration-sensitive prostate cancer, and non-metastatic castration-sensitive prostate cancer Compl. ¶42 The filing of the ANDA itself represents a significant commercial step to enter the market for enzalutamide upon its approval Compl. ¶13
IV. Analysis of Infringement Allegations
U.S. Patent No. 11,839,689 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a pharmaceutical composition comprising a solid dispersion | Macleods' Generic Products are alleged to be tablets that will contain a pharmaceutical composition comprising a solid dispersion of amorphous enzalutamide and HPMCAS. | ¶57 | col. 3:46-49 |
| consisting essentially of amorphous enzalutamide | The solid dispersion in the accused products is alleged to consist essentially of amorphous enzalutamide and HPMCAS. The complaint alleges Macleods copied the invention and does not dispute this composition. | ¶54; ¶57 | col. 2:50-54 |
| and hydroxypropyl methylcellulose acetate succinate ("HPMCAS") | The accused products' solid dispersion is alleged to contain HPMCAS. | ¶54; ¶57 | col. 3:46-49 |
Identified Points of Contention
- Scope Question: A potential dispute may center on the transitional phrase "consisting essentially of." The court may need to determine if Macleods' generic formulation contains any unlisted ingredients within the solid dispersion that materially affect the basic and novel properties of the invention (i.e., improved solubility and stability of amorphous enzalutamide).
- Technical Question: A factual question will be the precise composition of Macleods' product. While the complaint alleges that Macleods copied the formulation and does not dispute its composition in the notice letter Compl. ¶54 Compl. ¶55, discovery will be required to confirm the exact nature and properties of the excipients in the accused solid dispersion.
U.S. Patent No. 12,161,628 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method of treating prostate cancer in a patient | The proposed labeling for Macleods' Generic Products will allegedly direct its use for treating various forms of prostate cancer. | ¶69; ¶70 | col. 2:15-22 |
| to whom rifampin is administered, | The proposed labeling for the accused product will allegedly identify rifampin as a strong CYP3A4 inducer that interacts with enzalutamide, and the product will be administered to patients who are also receiving rifampin. | ¶69; ¶70 | col. 2:5-14 |
| comprising co-administering to the patient a daily dose of 240 mg of enzalutamide. | The proposed labeling will allegedly direct the co-administration of Macleods' Generic Products at a dose of 240 mg orally once daily in patients who are also receiving rifampin. | ¶69 | col. 2:15-22 |
Identified Points of Contention
- Legal Question: The primary legal question for this method claim will be one of induced infringement under 35 U.S.C. § 271(b). The analysis will turn on whether the instructions in Macleods' proposed product labeling are sufficient to demonstrate specific intent to encourage or instruct medical professionals to perform the patented method.
- Evidentiary Question: The court will need to examine the exact language of the proposed label for the accused generic product. The key question is whether the label goes beyond merely warning of a drug-drug interaction and instead affirmatively instructs or recommends the specific 240 mg dose adjustment when co-administered with rifampin, as required to prove inducement.
V. Key Claim Terms for Construction
The Term: "consisting essentially of" ('689 Patent, Claim 1)
Context and Importance
This transitional phrase is critical for defining the scope of the claimed "solid dispersion." Its construction will determine whether any unlisted substances in Macleods' formulation will place it outside the claim's scope. Practitioners may focus on this term because infringement will depend on whether any additional components in the accused product's dispersion are found to materially alter the invention's fundamental characteristics of improved solubility and bioavailability of amorphous enzalutamide.
Intrinsic Evidence for Interpretation
- Evidence for a Broader Interpretation: Language from the patent suggests that while the "solid dispersion" is a core two-component system, the overall "pharmaceutical composition" can include other additives like disintegrants and lubricants '689 Patent, col. 20:1-5 A party could argue this shows the patentees contemplated other ingredients, and "consisting essentially of" should not be read to exclude minor, conventional processing aids within the dispersion itself.
- Evidence for a Narrower Interpretation: The patent's abstract and detailed description repeatedly emphasize the combination of amorphous enzalutamide and a concentration-enhancing polymer as the key to the solution '689 Patent, abstract '689 Patent, col. 3:46-49 A party may argue that this focus implies that the "solid dispersion" itself must be limited to only these two components, plus any impurities that do not materially affect its novel properties.
The Term: "co-administering" ('628 Patent, Claim 1)
Context and Importance
The construction of this term is central to the induced infringement allegation. The infringement claim depends on Macleods' product label instructing doctors to "co-administer" the 240 mg dose of enzalutamide with rifampin. Practitioners may focus on whether the term, in the context of the patent, requires a specific affirmative instruction or can be satisfied by a label that simply describes the interaction and dose adjustment without explicit direction.
Intrinsic Evidence for Interpretation
- Evidence for a Broader Interpretation: The patent background describes the clinical problem of a drug-drug interaction that reduces enzalutamide exposure when given with a CYP3A4 inducer like rifampin '628 Patent, col. 2:5-14 This context suggests "co-administering" refers to the clinical situation where a patient is on a course of treatment with both drugs, supporting an interpretation that a label describing how to manage this situation is sufficient to encourage the claimed method.
- Evidence for a Narrower Interpretation: The claim language is specific: "comprising co-administering... a daily dose of 240 mg of enzalutamide." A party could argue that for inducement to occur, the accused label must explicitly direct or recommend this specific action, and that simply providing information about a potential dose adjustment in the context of a warning is not equivalent to an instruction to "co-administer" the claimed dose.
VI. Other Allegations
Indirect Infringement
The complaint alleges theories of both induced and contributory infringement for the method claims of the '357 and '128 patents, and induced infringement for the '628 patent. The primary basis for inducement is the allegation that Macleods' proposed product labeling will instruct and encourage physicians and patients to use the generic product in a way that directly infringes the patented methods Compl. ¶69 Compl. ¶87 Compl. ¶106 The basis for contributory infringement is that Macleods' products are especially made or adapted for an infringing use and are not staple articles of commerce suitable for substantial non-infringing use Compl. ¶85 Compl. ¶93 Compl. ¶104 Compl. ¶112
Willful Infringement
The complaint alleges that Macleods had pre-suit knowledge of the patents-in-suit, citing the patents' listing in the FDA's Orange Book and Macleods' own notice letter Compl. ¶59 Compl. ¶65 Compl. ¶86 Compl. ¶105 Plaintiffs further allege that Macleods' infringement is willful and that this case is "exceptional," asserting that Defendants' non-infringement and invalidity positions are "devoid of an objective good faith basis" Compl. ¶61 Compl. ¶76 Compl. ¶95 Compl. ¶114
VII. Analyst's Conclusion: Key Questions for the Case
- A core issue will be one of compositional identity: For the formulation patents ('689, '357, '128), the case will likely depend on a fact-intensive comparison of the accused generic product against the claims. Key questions for the court will be whether the accused product's solid dispersion "consists essentially of" amorphous enzalutamide and HPMCAS, and whether it meets the specific stability requirements recited in the '128 patent.
- A second central question will be one of induced infringement: For the method patents ('628, '357, '128), the disposition will hinge on the content of the defendant's proposed product label. The court will need to decide if the label's language constitutes active encouragement to perform the patented methods-specifically, the 240 mg dose adjustment with rifampin-or if it merely provides information without rising to the level of instruction required to establish specific intent for inducement.