DCT

1:17-cv-00304

Reckitt Benckiser LLC v. Amneal Pharma LLC

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:17-cv-00304, D.N.J., 01/13/2017
  • Venue Allegations: Plaintiff alleges venue is proper in the District of New Jersey because Defendant has its principal place of business and headquarters in the state, conducts substantial and continuous business there, and committed the act of infringement by sending a Notice Letter regarding its Abbreviated New Drug Application (ANDA) to Plaintiff's headquarters in New Jersey.
  • Core Dispute: Plaintiff alleges that Defendant’s filing of an ANDA to market generic versions of Plaintiff's Mucinex® DM products constitutes an act of infringement of three patents related to sustained-release pharmaceutical formulations containing guaifenesin.
  • Technical Context: The technology concerns oral drug delivery systems designed to provide a 12-hour therapeutic effect for active ingredients like guaifenesin, which has a naturally short plasma half-life.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendant’s submission of ANDA No. 209692 to the U.S. Food and Drug Administration. The complaint states that Defendant sent a Notice Letter dated November 28, 2016, which included a Paragraph IV Certification asserting that Plaintiff's patents are invalid, unenforceable, and/or will not be infringed by Defendant's proposed generic products. The complaint also notes the matter is related to prior litigation involving the same plaintiff, defendant, and patents.

Case Timeline

Date Event
2000-04-28 Earliest Priority Date for ’252, ’821, and ’032 Patents
2002-04-16 U.S. Patent No. 6,372,252 Issues
2004-04-29 FDA approves New Drug Application for Mucinex® DM
2005-10-18 U.S. Patent No. 6,955,821 Issues
2010-11-23 U.S. Patent No. 7,838,032 Issues
2016-11-28 Defendant sends ANDA Notice Letter to Plaintiff
2017-01-13 Complaint for Patent Infringement Filed

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

U.S. Patent No. 6,372,252 - "Guaifenesin sustained release formulation and tablets"

  • Issued: April 16, 2002.

The Invention Explained

  • Problem Addressed: The patent describes the challenge of formulating guaifenesin, an expectorant with a very short plasma half-life of approximately one hour. Immediate-release tablets require frequent dosing, leading to fluctuating blood concentrations and poor patient compliance. Prior sustained-release technologies often delayed the onset of therapeutic effect and failed to achieve a sufficiently high maximum serum concentration (Cmax) to be effective (’252 Patent, col. 1:21-44; col. 3:6-12).
  • The Patented Solution: The patent discloses a bi-layer tablet design to solve this problem. One layer provides an "immediate release" of guaifenesin to quickly achieve a therapeutic blood concentration. A second "sustained release" layer releases guaifenesin over an extended period of at least twelve hours. This sustained release is controlled by a specific "release-delaying matrix" comprising a combination of a hydrophilic polymer (which gels in the stomach) and a water-insoluble polymer (which dissolves more slowly in the intestines), achieving both a rapid onset and a prolonged duration of effect (’252 Patent, Abstract; col. 3:44-55).
  • Technical Importance: This bi-layer approach aimed to provide the "best of both worlds": the fast action of an immediate-release pill with the convenience and consistent therapeutic levels of a twice-daily sustained-release dosage form (’252 Patent, col. 2:38-50).

Key Claims at a Glance

  • The complaint does not identify specific asserted claims, alleging infringement of "one or more claims" (Compl. p. 9, ¶A). Independent claim 1 is representative of the core invention.
  • Independent Claim 1: A modified release tablet with the following essential elements:
    • Two portions: a first with an immediate release form of guaifenesin and a second with a sustained release form.
    • The second portion contains a "release-delaying matrix" comprising both a hydrophilic polymer and a water-insoluble polymer.
    • The weight ratio of the hydrophilic polymer to the water-insoluble polymer is between about 1:1 and 6.8:1.
    • The tablet demonstrates a maximum serum concentration (Cmax) in a human subject equivalent to that of a standard immediate release formulation.
    • The tablet provides therapeutically effective bioavailability for at least twelve hours after a single dose.

U.S. Patent No. 6,955,821 - "Sustained release formulations of guaifenesin and additional drug ingredients"

  • Issued: October 18, 2005.

The Invention Explained

  • Problem Addressed: This patent, a continuation-in-part of the ’252 patent, addresses the need to combine guaifenesin with other active ingredients—such as cough suppressants or decongestants—into a single, long-lasting tablet. Creating a combination therapy with different drugs, which may have different properties and required release profiles, presents formulation challenges beyond a single-ingredient tablet (’821 Patent, col. 7:4-18; col. 2:55-61).
  • The Patented Solution: The invention incorporates one or more additional drug ingredients into the bi-layer tablet structure disclosed in the ’252 patent. The additional drug(s) can be formulated into the immediate release layer, the sustained release layer, or both. This allows the release profile of the second drug to be tailored alongside guaifenesin, using the same underlying hydrophilic/water-insoluble polymer matrix to control the sustained release portion (’821 Patent, Abstract; col. 4:1-8).
  • Technical Importance: This technology enabled the development of multi-symptom cold and cough remedies in a single, twice-daily tablet, significantly improving convenience for patients who would otherwise need to manage multiple medications and dosing schedules (’821 Patent, col. 7:4-18).

Key Claims at a Glance

  • The complaint does not identify specific asserted claims (Compl. ¶34). Independent claim 1 is representative.
  • Independent Claim 1: A modified release drug product with the following essential elements:
    • A first quantity of guaifenesin in an immediate release formulation.
    • A second quantity of guaifenesin in a "release-delaying matrix."
    • At least one additional drug ingredient.
    • The release-delaying matrix comprises a hydrophilic polymer and a water-insoluble polymer in a weight ratio from about 1:1 to 9:1.
    • The product has a Cmax equivalent to a standard immediate release formulation and provides therapeutic bioavailability for at least twelve hours.

U.S. Patent No. 7,838,032 - "Sustained release of guaifenesin"

  • Issued: November 23, 2010.
  • Technology Synopsis: This patent continues the same line of invention, describing bi-layer guaifenesin tablets designed for rapid onset and 12-hour duration. The claims are distinguished by framing the invention in terms of achieving pharmacokinetic (PK) bioequivalence to a specific reference bi-layer tablet formulation detailed within the patent's specification, rather than a more generic "standard immediate release" tablet (’032 Patent, claims 1, 5). This suggests an effort to claim the specific, proven performance characteristics of the commercial embodiment of the earlier inventions.
  • Asserted Claims: The complaint does not identify specific asserted claims (Compl. ¶39). The patent contains independent claims 1 and 5.
  • Accused Features: The accused features are Amneal’s proposed generic guaifenesin and dextromethorphan extended-release tablets (Compl. ¶9, 21).

III. The Accused Instrumentality

Product Identification

  • Amneal’s proposed generic guaifenesin and dextromethorphan extended-release tablets, in 600 mg/30 mg and 1200 mg/60 mg dosage strengths, for which Amneal filed ANDA No. 209692 (Compl. ¶9, 21).

Functionality and Market Context

  • The complaint alleges that the accused products are "generic versions" of Plaintiff's Mucinex® DM products and are intended for the same use as an expectorant and cough suppressant (Compl. ¶14, 24). As generic products submitted for approval via an ANDA, they are intended to be therapeutically equivalent and substitutable for the brand-name drug. The act of infringement alleged is the filing of the ANDA itself under 35 U.S.C. § 271(e)(2), which allows for patent litigation before the generic product is launched (Compl. ¶29, 34, 39).
  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not provide detailed infringement contentions or claim charts. The infringement theory is based on Defendant's filing of an ANDA for a generic version of Plaintiff's Mucinex® DM, which is protected by the patents-in-suit. The core allegation is that to be approved as a generic, Defendant's product must be bioequivalent to Plaintiff's product and will therefore necessarily practice the patented technology.

U.S. Patent No. 6,372,252 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A modified release tablet having two portions, wherein a first portion comprises a first quantity of guaifenesin in an immediate release form...and a second portion comprises a second quantity of guaifenesin... Defendant's ANDA Products are alleged to be extended-release tablets that are generic versions of Plaintiff’s bi-layer Mucinex® DM product, which contains both immediate and sustained release components. ¶9, ¶14, ¶21 col. 20:46-51
...and a release-delaying matrix comprising a hydrophilic polymer and a water-insoluble polymer wherein the weight ratio of said hydrophilic polymer to said water-insoluble polymer is in the range of from about 1:1 to about 6.8:1... As alleged generic equivalents intended to match the release profile of Mucinex® DM, Defendant's ANDA Products are alleged to necessarily practice the patented release-delaying matrix technology that enables the product’s 12-hour efficacy. ¶14, ¶21, ¶24, ¶29 col. 20:50-54
...wherein said tablet demonstrates a Cmax in a human subject equivalent to the Cmax obtained when the first of three doses of a standard immediate release formulation...is dosed...and wherein said tablet also provides therapeutically effective bioavailability for at least twelve hours... The complaint alleges that Defendant, by filing an ANDA, seeks approval for a product that is bioequivalent to Plaintiff's Mucinex® DM product, which is alleged to exhibit the patented pharmacokinetic profile of a rapid onset (equivalent Cmax) and 12-hour duration. ¶14, ¶21, ¶24, ¶29 col. 20:55-62

Identified Points of Contention

  • Scope Questions: The primary dispute will likely center on whether Defendant's formulation falls within the scope of the claims. A key question for the court may be: Does Defendant’s product achieve bioequivalence using the specific two-polymer "release-delaying matrix" recited in the claims, or does it utilize a different formulation that "designs around" the patent?
  • Technical Questions: The complaint does not provide the composition of the accused product. A central technical question will be: What are the specific excipients and polymers used in Defendant’s ANDA product, and what is their ratio? Evidence on this point will be critical to determining literal infringement.

V. Key Claim Terms for Construction

  • The Term: "release-delaying matrix comprising a hydrophilic polymer and a water-insoluble polymer" (’252 Patent, Claim 1)

    • Context and Importance: This term defines the core technological mechanism of the sustained-release layer. Practitioners may focus on this term because Defendant's non-infringement defense is likely to argue that its formulation uses a different matrix, for instance one that does not rely on this specific combination of two distinct polymer types.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification provides extensive, non-limiting lists of suitable polymers for each category. For hydrophilic polymers, it lists natural gums, modified celluloses, and others (’252 Patent, col. 5:66–col. 6:11). For water-insoluble polymers, it lists polyacrylic acids, cellulose acetate phthalate, and others (’252 Patent, col. 6:35–42). This may support a construction that covers any combination of one polymer from each class.
      • Evidence for a Narrower Interpretation: The patent repeatedly emphasizes the specific combination of hydroxypropyl methylcellulose (a hydrophilic polymer) and an acrylic resin (a water-insoluble polymer) as a preferred embodiment that achieves the desired result (’252 Patent, Abstract; col. 6:19-23; col. 6:40-42). A party might argue that the term should be construed in light of these specific successful examples.

  • The Term: "Cmax... equivalent to the Cmax obtained when the first of three doses of a standard immediate release formulation ... is dosed" (’252 Patent, Claim 1)

    • Context and Importance: This is a functional limitation that defines the invention by its pharmacokinetic performance, not just its structure. The definition of "equivalent" and the identity of the "standard immediate release formulation" will be critical to determining whether this claim element is met.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The term "equivalent" is not explicitly defined, which may support using an established external standard, such as the FDA's statistical criteria for bioequivalence, which allows for a defined range of variation.
      • Evidence for a Narrower Interpretation: The patent includes figures showing the Cmax of its inventive formulation in direct comparison to an immediate-release product (Organidin® NR) (’252 Patent, FIG. 6). A party could argue that "equivalent" should mean a Cmax that is visually and numerically similar to the specific results disclosed and exemplified in the patent, rather than a broader regulatory standard.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that if Defendant commercially launches its ANDA products, it will induce and contribute to infringement by third parties (e.g., patients and doctors) under 35 U.S.C. §§ 271(b) and (c) (Compl. ¶31, 36, 41). The basis for an inducement claim would likely be the product's labeling and instructions, which would direct users to take the tablets for their intended, infringing purpose.
  • Willful Infringement: The complaint does not contain an explicit allegation of willful infringement.

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

  1. A core issue will be one of formulation design and claim scope: Does Amneal’s proposed generic product, which must be bioequivalent to Mucinex® DM, achieve this outcome using the specific "release-delaying matrix" comprising both a hydrophilic and a water-insoluble polymer as claimed, or does its formulation constitute a non-infringing "design around" the patents?

  2. A second central issue, stemming from Amneal's Paragraph IV certification, will be one of patent validity: Do the asserted claims, which recite specific polymer combinations and pharmacokinetic outcomes, represent a non-obvious and patentable invention over the state of the art in sustained-release pharmaceutical formulations prior to April 2000?

  3. The case may also turn on a question of functional equivalence: How should the court interpret the claim limitation requiring a Cmax "equivalent to" an immediate-release formulation? The resolution of whether this requires near-identical performance to the patent's examples or merely satisfaction of broader regulatory bioequivalence standards could be determinative of infringement.