DCT

1:26-cv-08057

Merck Sharp & Dohme LLC v. Alembic Pharma Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:26-cv-08057, D.N.J., 07/01/2026
  • Venue Allegations: Venue is alleged to be proper as to Defendant Alembic Inc. because its principal place of business is in New Jersey. Venue is alleged as to Defendant Alembic Ltd., a foreign corporation, based on its amenability to suit in any judicial district, its subjection to personal jurisdiction in New Jersey, and its alleged prior consent to venue in the district.
  • Core Dispute: Plaintiffs allege that Defendants' filing of an Abbreviated New Drug Application (ANDA) for a generic version of the antiviral drug PREVYMIS® (letermovir) constitutes an act of infringement of two U.S. patents.
  • Technical Context: The technology concerns the antiviral compound letermovir and its formulation for intravenous use in the prophylaxis of cytomegalovirus (CMV) infection, particularly in transplant recipients.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendants' submission of ANDA No. 221473 to the FDA. Plaintiffs received a Notice Letter from Defendants on May 19, 2026, and filed this complaint within the subsequent 45-day statutory window. The patents-in-suit are listed in the FDA's Approved Drug Products with Therapeutic Equivalence Evaluations (the "Orange Book") for PREVYMIS®.

Case Timeline

Date Event
2003-05-02 RE '791 Patent Priority Date
2012-02-29 '384 Patent Priority Date
2018-04-17 RE '791 Patent Issue Date
2020-03-31 '384 Patent Issue Date
2026-05-19 Plaintiffs receive ANDA Notice Letter from Alembic
2026-07-01 Complaint Filing Date

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

U.S. Reissued Patent No. RE 46,791 - "Substituted Dihydroquinazolines"

The Invention Explained

  • Problem Addressed: The patent addresses the need for novel antiviral agents, particularly for treating infections caused by cytomegaloviruses (CMV), due to the potential for existing therapies to develop resistance RE '791 Patent, col. 1:26-29
  • The Patented Solution: The patent discloses a class of compounds known as substituted dihydroquinazolines that exhibit antiviral activity RE '791 Patent, abstract The core of the invention is the chemical structure of these compounds, including the specific compound known as letermovir, which is identified as an effective agent against CMV RE '791 Patent, col. 1:31-35 RE '791 Patent, col. 77:7-14
  • Technical Importance: These compounds provide a new class of therapeutic agents for managing CMV, a significant cause of morbidity and mortality in immunocompromised patient populations, such as organ transplant recipients RE '791 Patent, col. 11:21-40

Key Claims at a Glance

  • The complaint asserts dependent claims 23 and 24, which depend from independent claim 1 Compl. ¶34
  • Independent Claim 1 recites a broad genus of compounds of formula (I).
  • Dependent Claim 23 narrows claim 1 to a specific chemical compound, the (S)-enantiomer of letermovir.
  • Dependent Claim 24 narrows claim 1 to the (R)-enantiomer of the same compound.

U.S. Patent No. 10,603,384 - "Pharmaceutical Composition Containing an Antivirally Active Dihydroquinazoline Derivative"

The Invention Explained

  • Problem Addressed: The background of the patent describes solubility issues with the active ingredient, letermovir, which complicates the creation of stable, long-term formulations suitable for intravenous administration '384 Patent, col. 1:24-29
  • The Patented Solution: The patent claims a specific pharmaceutical formulation that solves the stability problem by combining letermovir with particular excipients, including hydroxypropyl-β-cyclodextrin, within a defined pH range '384 Patent, abstract '384 Patent, col. 2:6-16 This combination creates a stable solution that can be stored and administered intravenously.
  • Technical Importance: This formulation technology enables the safe and effective intravenous delivery of letermovir, providing a critical administration route for patients who may be unable to take oral medications.

Key Claims at a Glance

  • The complaint asserts independent claim 1 Compl. ¶53
  • Essential elements of independent claim 1 include:
    • A compound which is the (S)-enantiomer of letermovir, or a salt or solvate thereof.
    • At least one excipient which is a hydroxypropyl-β-cyclodextrin.
    • Water.
    • Specific concentrations of the compound (0.5-2.5 g per 100 ml) and the hydroxypropyl-β-cyclodextrin (10.0-30.0 g per 100 ml).
    • The further presence of NaOH and NaCl.
    • The composition is in a form suitable for intravenous administration.
    • The composition has a pH in the range of 7.0 to 8.5.

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is Defendants' "Alembic's ANDA Product," identified as a generic version of PREVYMIS® (letermovir) injection, for which Defendants seek FDA approval under ANDA No. 221473 Compl., Nature of the Action

Functionality and Market Context

  • The accused product is a pharmaceutical formulation of letermovir intended for intravenous administration in single-dose vials of 240 mg/12 mL and 480 mg/24 mL Compl. ¶42 Compl. ¶59 The complaint alleges the product is intended for the prophylaxis of CMV infection and disease Compl. ¶47 Compl. ¶64 It is alleged to be bioequivalent to Plaintiffs' PREVYMIS® product and, if approved, would be marketed as a competing generic product Compl., Nature of the Action Compl. ¶43

IV. Analysis of Infringement Allegations

RE '791 Patent Infringement Allegations

Claim Element (from Independent Claim 1, as specified in Dependent Claim 23) Alleged Infringing Functionality Complaint Citation Patent Citation
The compound of claim 1, wherein said compound is: [structure of (S)-letermovir] or a physiologically acceptable salt thereof. Alembic's ANDA Product is alleged to contain letermovir as its active pharmaceutical ingredient. The complaint provides a chemical structure diagram of the (S)-enantiomer of letermovir, the compound allegedly contained in the accused product (Compl. ¶35). ¶42 col. 77:7-14
  • Identified Points of Contention:
    • Scope Questions: The complaint asserts infringement of both claim 23, which covers the (S)-enantiomer of letermovir, and claim 24, which covers the (R)-enantiomer Compl. ¶34 Since the active drug PREVYMIS® is the (S)-enantiomer, the basis for alleging infringement of the claim to the (R)-enantiomer raises a question about the complaint's theory or the precise stereoisomeric content of the accused product.

'384 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a) a compound which is {8-fluoro-2-[4-(3-methoxyphenyl)piperazine-1-yl]-3-[2-methoxy-5-(trifluoromethyl)phenyl]-3,4-dihydroquinazoline-4-yl}acetic acid, wherein the carbon in position 4 of the dihydroquinazoline has a ring (S)-configuration, a salt thereof, a solvate thereof, or a solvate of a salt thereof The active ingredient in the accused product is alleged to be letermovir, which is the (S)-enantiomer of the named compound. ¶59 col. 24:2-10
b) at least one excipient wherein said excipient is a hydroxypropyl-β-cyclodextrin The complaint alleges the ANDA product is covered by claim 1 but does not provide specific factual allegations regarding the presence of this excipient. ¶55 col. 24:10-11
c) water The accused product is described as an "injection" in vials, which implies a water-based solution. ¶59 col. 24:12
wherein 100 ml of said composition contains: i) 0.5-2.5 g [of the compound] The accused product is formulated at 240 mg/12 mL and 480 mg/24 mL, which is equivalent to 2.0 g per 100 mL. ¶59 col. 24:14-23
wherein 100 ml of said composition contains: ii) 10.0-30.0 g of hydroxypropyl-β cyclodextrin The complaint does not provide specific factual allegations regarding the concentration of this excipient. ¶55 col. 24:23-25
wherein said composition further comprises NaOH and NaCl The complaint does not provide specific factual allegations regarding the presence of NaOH and NaCl. ¶55 col. 24:28-29
wherein said composition is in a form suitable for intravenous administration The accused product is described as an "injection" in "single-dose vials," indicating it is suitable for intravenous use. ¶59 col. 24:29-30
wherein said composition has a pH in the range from 7.0 to 8.5 The complaint does not provide specific factual allegations regarding the pH of the accused product. ¶55 col. 24:32-33
  • Identified Points of Contention:
    • Technical Questions: A central question for the '384 patent will be evidentiary: does the accused product actually contain all the formulation components recited in claim 1? The complaint alleges infringement of the claim but provides no specific facts regarding the presence or concentration of hydroxypropyl-β-cyclodextrin, the presence of NaOH and NaCl, or the product's pH. Infringement will depend on discovering these formulation details.

V. Key Claim Terms for Construction

  • The Term: "hydroxypropyl-β-cyclodextrin" (from claim 1 of the '384 Patent)
  • Context and Importance: This excipient is a required element for a finding of infringement of the '384 patent. The definition of this term could become critical if the accused product uses a variant of hydroxypropyl-β-cyclodextrin that Defendants argue falls outside the scope of the claim. Practitioners may focus on this term because its construction could determine whether the specific formulation used by the generic manufacturer infringes.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The language in claim 1 does not qualify the term, suggesting it covers all chemical entities meeting that name '384 Patent, col. 24:10-11 The specification also lists it as one example among a broader class of "modified β-cyclodextrins," which could support an interpretation that is not unduly narrow '384 Patent, col. 3:7-11
    • Evidence for a Narrower Interpretation: The patent's examples repeatedly refer to a specific commercial grade, "hydroxypropyl-β-cyclodextrin HP5 (Kleptose HPB, Roquette)" '384 Patent, col. 17:35-37 A party might argue this disclosure limits the claim scope to that specific type or to variants with a similar degree of substitution or properties, potentially distinguishing it from a different variant used in the accused product.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for both patents. Inducement is based on allegations that Defendants intend to sell the product with a label that instructs and encourages administration for the patented use Compl. ¶47 Compl. ¶64 Contributory infringement is based on the allegation that the product is especially made for an infringing use and is not suitable for substantial noninfringing use Compl. ¶49 Compl. ¶67
  • Willful Infringement: The complaint does not use the term "willful," but it alleges that Defendants have knowledge of the patents-in-suit because they are listed in the FDA's Orange Book for PREVYMIS® Compl. ¶46 Compl. ¶63 It further alleges that, despite this knowledge, Defendants are proceeding with their intent to market the product. These allegations of pre-suit knowledge may form the basis for a future claim of willful infringement.

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

  • A central issue for the RE '791 patent will be one of compound identity and validity. Assuming the accused product contains the (S)-enantiomer of letermovir, infringement appears direct, shifting the focus to Defendants' likely defense that the claims are invalid as obvious over the prior art. The complaint's concurrent assertion of a claim to the (R)-enantiomer raises a secondary question about the precise stereochemical makeup of the accused product.
  • A key evidentiary question for the '384 patent will be one of compositional identity. The infringement case hinges on whether the accused product's formulation includes not just letermovir but also the specific excipients (hydroxypropyl-β-cyclodextrin, NaOH, NaCl) in the claimed concentrations and possesses the claimed pH. The complaint is currently silent on these factual elements, making their discovery critical to proving infringement.
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