DCT

2:23-cv-03494

Amring Pharma Inc v. Rubicon Research Pvt Ltd

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:23-cv-03494, D.N.J., 06/28/2023
  • Venue Allegations: Plaintiff alleges venue is proper in the District of New Jersey because Defendant maintains a "Business Development and Regulatory Office" in Plainsboro, New Jersey, where it is believed the Abbreviated New Drug Application (ANDA) at issue was prepared, and because Defendant intends to market and sell the accused generic product in New Jersey.
  • Core Dispute: Plaintiff alleges that Defendant's submission of an ANDA to the FDA seeking approval to market a generic version of Plaintiff's LYSTEDA® tablets constitutes an act of infringement of eight U.S. patents directed to tranexamic acid formulations.
  • Technical Context: The technology relates to modified-release oral formulations of tranexamic acid, an antifibrinolytic agent used to treat heavy menstrual bleeding (menorrhagia).
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendant's notification to Plaintiff, via a Paragraph IV Certification letter dated May 18, 2023, of its filing of ANDA No. 218320. The filing of the ANDA itself constitutes the statutory act of infringement alleged in the complaint.

Case Timeline

Date Event
2004-03-04 Earliest Priority Date for all Patents-in-Suit
2011-05-24 U.S. Patent No. 7,947,739 Issued
2011-09-20 U.S. Patent No. 8,022,106 Issued
2012-09-25 U.S. Patent No. 8,273,795 Issued
2013-07-16 U.S. Patent No. 8,487,005 Issued
2014-07-29 U.S. Patent No. 8,791,160 Issued
2014-08-19 U.S. Patent No. 8,809,394 Issued
2015-02-17 U.S. Patent No. 8,957,113 Issued
2015-06-23 U.S. Patent No. 9,060,939 Issued
2023-05-18 Defendant's Paragraph IV Certification Notice Letter
2023-06-28 Complaint Filing Date

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

U.S. Patent No. 7,947,739 - "Tranexamic Acid Formulations," Issued May 24, 2011

The Invention Explained

  • Problem Addressed: The patent describes that conventional oral treatments for heavy menstrual bleeding using tranexamic acid can cause adverse gastrointestinal reactions such as nausea, vomiting, and diarrhea (’739 Patent, col. 1:40-45). These side effects are attributed to the "quantity of tranexamic acid and/or rapid rate of release of tranexamic acid into the stomach with each dose" (’739 Patent, col. 1:45-49).
  • The Patented Solution: The invention provides a modified-release oral tablet formulated to release tranexamic acid in a "designed fashion to prevent a bolus of tranexamic acid being introduced into the stomach" (’739 Patent, col. 5:9-11). By reducing the concentration of the drug dissolved in the stomach at any given time, the formulation aims to minimize or eliminate the associated gastrointestinal side effects, thereby improving patient compliance with the therapy (’739 Patent, col. 5:11-24).
  • Technical Importance: This modified-release approach provides a non-hormonal medical therapy option for a common condition that avoids the tolerability issues of immediate-release formulations and the invasiveness of surgical procedures (’739 Patent, col. 5:61-65).

Key Claims at a Glance

  • The complaint asserts infringement of one or more claims of the ’739 Patent, and Claim 1 is the first independent claim (Compl. ¶23).
  • Claim 1 recites:
    • A tranexamic acid tablet formulation comprising tranexamic acid or a pharmaceutically acceptable salt thereof;
    • A modified release material comprising a polymer selected from a specific group (hydroxyalkylcelluloses, alkylcelluloses, etc.);
    • Wherein the modified release material is present in an amount from about 10% to about 35% by weight of the formulation;
    • Wherein the formulation provides a specified in-vitro dissolution release rate (less than about 70% released at 45 minutes and about 100% released by 120 minutes); and
    • Wherein each tablet provides a dose of about 650 mg of tranexamic acid.
  • The complaint reserves the right to assert additional claims (Compl. ¶23).

U.S. Patent No. 8,022,106 - "Tranexamic Acid Formulations," Issued September 20, 2011

The Invention Explained

  • Problem Addressed: The patent addresses the same technical problem as the ’739 Patent: adverse gastrointestinal side effects associated with immediate-release oral tranexamic acid formulations used for treating heavy menstrual bleeding (’106 Patent, col. 2:38-48).
  • The Patented Solution: The invention is an oral dosage form containing tranexamic acid and a modified release material. The formulation is specifically designed to be "suitable for administration on a two or three times a day basis" while providing a release profile that avoids a large "bolus of tranexamic acid being introduced into the stomach," thereby reducing GI side effects (’106 Patent, col. 6:4-13, 25-29).
  • Technical Importance: By enabling a less frequent dosing regimen (twice or three times daily) with improved tolerability, the invention seeks to enhance patient compliance and provide a more practical treatment option for a chronic, persistent condition (’106 Patent, col. 6:18-24).

Key Claims at a Glance

  • The complaint asserts infringement of one or more claims of the ’106 Patent, and Claim 1 is the first independent claim (Compl. ¶28).
  • Claim 1 recites:
    • A tranexamic acid oral dosage form comprising tranexamic acid or a pharmaceutically acceptable salt thereof;
    • A modified release material which provides for the modified release of the tranexamic acid;
    • Such that the dosage form is suitable for administration on a two or three times a day basis;
    • And wherein the dosage form provides a specified in-vitro dissolution release rate (less than about 70% released at 45 minutes and about 100% released by 120 minutes).
  • The complaint reserves the right to assert additional claims (Compl. ¶28).

Multi-Patent Capsule: U.S. Patent No. 8,273,795

  • Patent Identification: U.S. Patent No. 8,273,795, "Tranexamic Acid Formulations," Issued September 25, 2012 (Compl. ¶10).
  • Technology Synopsis: This patent addresses the same problem of GI side effects from tranexamic acid (’795 Patent, col. 2:39-49). The claimed invention is a method of treating a patient by administering a modified release oral dosage form of tranexamic acid to provide a specific pharmacokinetic profile, including a mean maximum plasma concentration (Cmax) of from about 5 to about 17.5 mcg/ml after a single dose (’795 Patent, col. 7:7-14).
  • Asserted Claims: One or more claims are asserted (Compl. ¶33). Independent claim 1 is a method of treatment claim.
  • Accused Features: Defendant's submission of ANDA No. 218320 for a generic 650 mg tablet that is represented as being bioequivalent to Plaintiff's LYSTEDA® product (Compl. ¶18, 33).

Multi-Patent Capsule: U.S. Patent No. 8,487,005

  • Patent Identification: U.S. Patent No. 8,487,005, "Tranexamic Acid Formulations," Issued July 16, 2013 (Compl. ¶11).
  • Technology Synopsis: This patent is directed to a modified-release tablet formulation of tranexamic acid containing specific polymeric release materials (’005 Patent, col. 1:15-20). The claims focus on a formulation comprising a specific polymer (e.g., hydroxypropylmethylcellulose) within a defined weight percentage range and a specific dissolution profile, similar to the ’739 patent (’005 Patent, Claim 1).
  • Asserted Claims: One or more claims are asserted (Compl. ¶38). Independent claim 1 is a formulation claim.
  • Accused Features: Defendant's submission of ANDA No. 218320 for a generic 650 mg tablet that is represented as being bioequivalent to Plaintiff's LYSTEDA® product (Compl. ¶18, 38).

Multi-Patent Capsule: U.S. Patent No. 8,791,160

  • Patent Identification: U.S. Patent No. 8,791,160, "Tranexamic Acid Formulations," Issued July 29, 2014 (Compl. ¶12).
  • Technology Synopsis: This patent claims a specific tranexamic acid tablet formulation comprising hydroxypropylmethylcellulose as the modified release material (’160 Patent, col. 1:15-20). The claims specify the amount of the release material (10% to 35% by weight) and a particular dissolution profile, similar to other patents in the family (’160 Patent, Claim 1).
  • Asserted Claims: One or more claims are asserted (Compl. ¶43). Independent claim 1 is a formulation claim.
  • Accused Features: Defendant's submission of ANDA No. 218320 for a generic 650 mg tablet represented as being bioequivalent to Plaintiff's LYSTEDA® product (Compl. ¶18, 43).

Multi-Patent Capsule: U.S. Patent No. 8,809,394

  • Patent Identification: U.S. Patent No. 8,809,394, "Tranexamic Acid Formulations," Issued August 19, 2014 (Compl. ¶13).
  • Technology Synopsis: This patent claims a modified-release oral dosage form of tranexamic acid defined by its suitability for a specific dosing regimen (twice or three times a day) and a particular dissolution profile (’394 Patent, col. 6:30-41). The claims are similar in structure to those of the ’106 patent.
  • Asserted Claims: One or more claims are asserted (Compl. ¶48). Independent claim 1 is a formulation claim.
  • Accused Features: Defendant's submission of ANDA No. 218320 for a generic 650 mg tablet represented as being bioequivalent to Plaintiff's LYSTEDA® product (Compl. ¶18, 48).

Multi-Patent Capsule: U.S. Patent No. 8,957,113

  • Patent Identification: U.S. Patent No. 8,957,113, "Tranexamic Acid Formulations," Issued February 17, 2015 (Compl. ¶14).
  • Technology Synopsis: This patent claims a method of treating menorrhagia by orally administering a specific dosage (two 650 mg tablets) of a modified-release tranexamic acid formulation (’113 Patent, col. 1:15-20). The claims recite the formulation's composition and dissolution profile, which are alleged to be infringed by the use of the ANDA product (’113 Patent, Claim 1).
  • Asserted Claims: One or more claims are asserted (Compl. ¶53). Independent claim 1 is a method of treatment claim.
  • Accused Features: Defendant's submission of ANDA No. 218320 and its proposed labeling, which allegedly instructs for an infringing use of its generic 650 mg tablet (Compl. ¶18, 54).

Multi-Patent Capsule: U.S. Patent No. 9,060,939

  • Patent Identification: U.S. Patent No. 9,060,939, "Tranexamic Acid Formulations," Issued June 23, 2015 (Compl. ¶15).
  • Technology Synopsis: This patent claims a dosage form comprising tranexamic acid and hydroxypropylmethylcellulose as a release material, defined by a specific dissolution profile where a certain percentage of the drug is released every 15 minutes (’939 Patent, col. 1:15-20). This provides another definitional approach to the same modified-release concept (’939 Patent, Claim 1).
  • Asserted Claims: One or more claims are asserted (Compl. ¶58). Independent claim 1 is a formulation claim.
  • Accused Features: Defendant's submission of ANDA No. 218320 for a generic 650 mg tablet represented as being bioequivalent to Plaintiff's LYSTEDA® product (Compl. ¶18, 58).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is Defendant's generic 650 mg tranexamic acid tablets described in ANDA No. 218320, which seeks FDA approval as a generic version of Plaintiff's LYSTEDA® tablets (Compl. ¶1, 6).

Functionality and Market Context

  • The complaint alleges that by filing its ANDA, Defendant has represented to the FDA that its generic product has the same active ingredient, route of administration, dosage form, and strength as LYSTEDA®, and is bioequivalent to LYSTEDA® (Compl. ¶18). The complaint alleges that LYSTEDA®'s formulation and dosing are covered by the patents-in-suit (Compl. ¶16). The infringement alleged is both the statutory act of filing the ANDA itself and the future manufacture, use, and sale of the generic tablets upon FDA approval (Compl. ¶1, 17). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

7,947,739 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A tranexamic acid tablet formulation, comprising: tranexamic acid...wherein each tablet of the formulation provides a dose of about 650 mg of tranexamic acid. Defendant's ANDA product is a 650 mg tranexamic acid tablet. ¶6 col. 6:49-51
a modified release material, wherein the modified release material comprises a polymer selected from the group consisting of hydroxyalkylcelluloses, alkylcelluloses, cellulose ethers, partial esters thereof, and mixtures thereof; wherein the modified release material is present in the formulation in an amount from about 10% to about 35% by weight of the formulation It is alleged that Defendant's ANDA product is a generic version of and bioequivalent to LYSTEDA®, which is covered by the patent, and therefore contains the claimed modified release material in the claimed amount. ¶16, ¶18 col. 6:52-59
wherein the formulation provides an in-vitro dissolution release rate of...less than about 70% by weight...released at about 45 minutes, and about 100% by weight...released by about 120 minutes It is alleged that Defendant's ANDA product, to be bioequivalent to LYSTEDA®, will meet the claimed dissolution profile. ¶18, ¶23 col. 6:59-65

8,022,106 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A tranexamic acid oral dosage form comprising: tranexamic acid or a pharmaceutically acceptable salt thereof; and a modified release material It is alleged that Defendant's ANDA product is a generic oral dosage form of tranexamic acid that contains a modified release material making it bioequivalent to LYSTEDA®. ¶1, ¶18 col. 7:4-7
such that the dosage form is suitable for administration on a two or three times a day basis Defendant's proposed product labeling is alleged to provide instructions for use that mirror the approved dosing for LYSTEDA®, which is suitable for administration two or three times a day. ¶18, ¶24 col. 7:8-10
said dosage form providing an in-vitro dissolution release rate of...less than about 70% by weight...released at about 45 minutes, and about 100% by weight...released by about 120 minutes It is alleged that Defendant's ANDA product, to be bioequivalent to LYSTEDA®, will meet the claimed dissolution profile. ¶18, ¶28 col. 7:11-17

Identified Points of Contention

  • Scope Questions: A central question will be whether Defendant's ANDA product, by virtue of being represented as "bioequivalent" to LYSTEDA®, necessarily meets every limitation of the asserted claims. The court may need to determine if different excipients or release mechanisms used in the generic product fall within the scope of terms like "modified release material," even if the resulting pharmacokinetic profile is the same.
  • Technical Questions: The complaint does not provide the composition of Defendant's generic formulation. A key technical question for discovery will be: what specific excipients does the ANDA product use to control the release of tranexamic acid, and what is its actual in-vitro dissolution profile? The infringement analysis will depend on whether this undisclosed formulation literally reads on, or is equivalent to, the claimed formulations.

V. Key Claim Terms for Construction

The Term: "modified release material"

(asserted in claims of '739 and '106 patents, among others)

  • Context and Importance: This term is the core of the inventions, distinguishing them from prior art immediate-release formulations. The infringement dispute will likely depend on whether the specific excipients and formulation technology used in Defendant's ANDA product fall within the construed scope of this term.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification of the ’739 Patent provides a list of suitable polymers for the modified release material, including "hydroxypropylmethylcellulose or hypromellose, carboxymethylcellulose, polyvinyl alcohol, etc." (’739 Patent, col. 19:1-8). This list suggests the term is not limited to a single chemical but encompasses a class of functional excipients.
    • Evidence for a Narrower Interpretation: Claim 1 of the ’739 Patent narrows the definition to a specific polymer group ("hydroxyalkylcelluloses, alkylcelluloses, cellulose ethers, partial esters thereof, and mixtures thereof"). A defendant may argue that this claim language, along with the specific use of hypromellose in the patent's examples, limits the scope to only the disclosed classes of polymers (’739 Patent, col. 28:27-41).

The Term: "about 650 mg"

(asserted in claims of '739 patent, among others)

  • Context and Importance: Practitioners may focus on this term because pharmaceutical manufacturing involves inherent variability. The scope of "about" could become dispositive if the Defendant's product, while nominally 650 mg, has a specified range or average manufactured amount that is slightly different.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The term "about" itself implies some degree of variance is acceptable. The specification of the ’739 Patent also discusses dosage forms comprising "from about 585 mg to about 715 mg of tranexamic acid" (’739 Patent, col. 9:8-10), which may be used to argue that "about 650 mg" covers this entire range.
    • Evidence for a Narrower Interpretation: A defendant may argue that in the context of an FDA-regulated dosage strength, "about 650 mg" should be construed very narrowly to mean the approved dosage strength with only minor, standard manufacturing tolerances, and not the broader range disclosed in the specification for exemplary purposes.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon FDA approval, Defendant will actively induce infringement by providing instructions to healthcare providers and patients, via proposed product labeling, to use the generic tablets in a manner that directly infringes the asserted method claims (Compl. ¶24, 29, 34, 39, 44, 49, 54, 59).
  • Willful Infringement: The complaint does not contain an explicit count for willful infringement. However, it does allege that Defendant had "actual and constructive knowledge" of each patent-in-suit prior to filing its ANDA and was aware that the filing constituted an act of infringement (Compl. ¶25, 30, 35, 40, 45, 50, 55, 60). These allegations of pre-suit knowledge could form a basis for a later claim of willfulness.

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

  • A core issue will be one of infringement by equivalence in an ANDA context: Will the court determine that Defendant's representation of bioequivalence to the FDA is sufficient to establish that its product will necessarily infringe the asserted claims, or will Plaintiff be required to prove through discovery and testing that the specific, undisclosed formulation of the ANDA product meets every claim limitation, either literally or under the doctrine of equivalents?
  • A central question of claim construction will define the case's scope: Will the term "modified release material," which is central to all asserted patents, be construed broadly to encompass any excipient blend that achieves the claimed dissolution and pharmacokinetic outcomes, or will it be limited more narrowly to the specific classes of cellulosic polymers explicitly disclosed in the patents' specifications?
  • An underlying evidentiary question will be one of technical comparison: Once the composition of the accused generic product is revealed in discovery, the case will turn on a direct comparison of its excipients and dissolution performance against the language of the asserted claims, making the details of the ANDA filing the central evidence in the dispute.