DCT

1:18-cv-00855

Purdue Pharma LP v. Ascent Pharma Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:18-cv-00855, D. Del., 06/07/2018
  • Venue Allegations: Plaintiffs allege venue is proper based on Defendant's stipulation not to contest it in this case, and through Defendant's relationship with Camber Pharmaceuticals, Inc., a Delaware corporation with which Defendant allegedly operates as an integrated business.
  • Core Dispute: Plaintiffs allege that Defendant's submission of an Abbreviated New Drug Application (ANDA) to market generic versions of Purdue's OxyContin® infringes seven U.S. patents related to abuse-deterrent formulations and specific chemical purity levels for oxycodone.
  • Technical Context: The patents address two major issues in the field of opioid analgesics: deterring abuse of controlled-release formulations and minimizing potentially harmful impurities generated during the manufacturing process.
  • Key Procedural History: The complaint notes that certain claims of U.S. Patent No. 8,309,060 were previously found infringed but invalid for obviousness in a separate litigation (the Endo cases). It further states that the appeal of that decision was dismissed after the defendants in that case withdrew their ANDAs, and that a motion to vacate the invalidity judgment is now pending. This history may introduce questions regarding the potential for collateral estoppel.

Case Timeline

Date Event
2001-08-06 Priority Date for U.S. Patent Nos. 9,060,976 and 9,861,582
2003-06-16 Priority Date for U.S. Patent No. 9,675,610
2003-08-06 Priority Date for U.S. Patent No. 8,309,060
2004-03-30 Priority Date for U.S. Patent Nos. 9,073,933 and 9,522,919
2012-11-13 U.S. Patent No. 8,309,060 Issued
2013-02-04 Priority Date for U.S. Patent No. 9,149,533
2015-06-23 U.S. Patent No. 9,060,976 Issued
2015-07-07 U.S. Patent No. 9,073,933 Issued
2015-10-06 U.S. Patent No. 9,149,533 Issued
2016-12-20 U.S. Patent No. 9,522,919 Issued
2017-06-13 U.S. Patent No. 9,675,610 Issued
2017-11-27 Defendant files ANDA No. 211178 (on or before this date)
2018-01-09 U.S. Patent No. 9,861,582 Issued
2018-06-07 Complaint Filed

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

U.S. Patent No. 9,060,976 - "Pharmaceutical Formulation Containing Gelling Agent"

  • Patent Identification: 9,060,976, "Pharmaceutical Formulation Containing Gelling Agent", issued June 23, 2015.

The Invention Explained

  • Problem Addressed: The patent addresses the widespread abuse of opioid analgesics, particularly the practice of crushing controlled-release tablets to extract the active ingredient for immediate parenteral (e.g., injection) or intranasal administration, which produces a rapid euphoric effect (’976 Patent, col. 1:16-39).
  • The Patented Solution: The invention is an oral dosage form containing a gelling agent. When an abuser crushes the tablet and mixes it with a small amount of liquid (e.g., water), the formulation creates a viscous gel. This gel is difficult to draw into a syringe and inject, and if administered nasally, it forms a gel that sticks to the nasal passages, thereby minimizing absorption and deterring abuse ('976 Patent, col. 3:1-24). The formulation is prepared using a heating process to melt at least a portion of the polyethylene oxide (PEO) in the core matrix, which is then coated ('976 Patent, col. 9:18-24).
  • Technical Importance: This technology represents an approach to creating abuse-deterrent formulations by altering the physical properties of the drug upon tampering, making illicit administration more difficult and less rewarding without changing the therapeutic effect when taken as prescribed ('976 Patent, col. 2:42-51).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶47).
  • Claim 1 requires:
    • An extended release abuse deterrent dosage form
    • comprising a core matrix comprising PEO having a molecular weight of from about 300,000 daltons to about 5,000,000 daltons and oxycodone or a pharmaceutically acceptable salt thereof
    • wherein the core matrix is heated to melt at least a portion of the PEO
    • and PEG applied onto the core matrix
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 9,073,933 - "Oxycodone Hydrochloride Having Less Than 25 PPM 14-Hydroxycodeinone"

  • Patent Identification: 9,073,933, "Oxycodone Hydrochloride Having Less Than 25 PPM 14-Hydroxycodeinone", issued July 7, 2015.

The Invention Explained

  • Problem Addressed: The patent background describes that the synthesis of oxycodone from thebaine can create an impurity, 14-hydroxycodeinone, which is an alpha, beta, unsaturated ketone. The patent notes that existing commercial oxycodone active pharmaceutical ingredient (API) contains this impurity at levels greater than 100 parts per million (ppm) (’933 Patent, col. 2:1-12).
  • The Patented Solution: The invention provides a final oxycodone hydrochloride composition with a significantly reduced level of this specific impurity (less than 25 ppm). This is achieved through a manufacturing process that includes hydrogenation under specific conditions to reduce the impurity to the claimed low level, addressing potential safety and quality concerns ('933 Patent, Abstract; col. 3:1-10).
  • Technical Importance: By providing a method to produce a higher purity oxycodone API, the invention addresses regulatory and safety demands for minimizing potentially harmful impurities in pharmaceutical products ('933 Patent, col. 2:13-19).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶54).
  • Claim 1 requires:
    • An oxycodone hydrochloride composition
    • having less than 25 ppm of 14-hydroxycodeinone
  • The complaint states that one or more claims are infringed, including but not limited to claim 1, suggesting other claims may be asserted later (Compl. ¶54).

No probative visual evidence provided in complaint.

Multi-Patent Capsules

  • Patent Identification: 9,522,919, "Oxycodone Compositions", issued December 20, 2016.

    • Technology Synopsis: This patent is directed to oxycodone hydrochloride compositions with a specific low ratio of a different impurity, 8α,14-dihydroxy-7,8-dihydrocodeinone, to oxycodone hydrochloride (’919 Patent, Abstract). This impurity is an intermediate that can be carried through the manufacturing process and convert to 14-hydroxycodeinone.
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶61).
    • Accused Features: Defendant's ANDA Products are alleged to be compositions meeting the claimed purity ratio (Compl. ¶61).

  • Patent Identification: 9,149,533, "Tamper Resistant Pharmaceutical Formulations", issued October 6, 2015.

    • Technology Synopsis: This patent discloses a solid oral dosage form designed to be tamper-resistant. The formulation includes a "heat-labile gelling agent" which forms a viscous gel upon tampering, but whose viscosity is reduced by heat, and a "thermal stabilizer" to counteract this heat-induced viscosity reduction (’533 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶68).
    • Accused Features: Defendant's ANDA Products are alleged to contain the claimed combination of a heat-labile gelling agent, thermal stabilizer, drug, and pH modifying agent (Compl. ¶68).

  • Patent Identification: 9,861,582, "Pharmaceutical Formulation Containing Gelling Agent", issued January 9, 2018.

    • Technology Synopsis: This patent claims a method of preparing an abuse-deterrent dosage form. The method involves creating a matrix with oxycodone and a specific gelling agent (polyethylene oxide of a particular molecular weight) and then applying a coating of polyvinyl alcohol to the matrix (’582 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶75).
    • Accused Features: The manufacture of Defendant's ANDA Products is alleged to practice the claimed method (Compl. ¶75).

  • Patent Identification: 8,309,060, "Abuse-Proofed Dosage Form", issued November 13, 2012.

    • Technology Synopsis: This patent describes a dosage form made abuse-proof through mechanical resistance. The invention is a thermoformed dosage form containing a polymer that gives the final tablet a high breaking strength of at least 500 Newtons, making it difficult to crush or pulverize with conventional means (’060 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶82).
    • Accused Features: Defendant's ANDA Products are alleged to be thermoformed dosage forms with the claimed breaking strength (Compl. ¶82).

  • Patent Identification: 9,675,610, "Abuse-Proofed Dosage Form", issued June 13, 2017.

    • Technology Synopsis: This patent covers a solid dosage form with a viscosity-increasing agent. When the dosage form is crushed and mixed with water, it forms a gel that can be drawn into a hypodermic needle but, when injected into a further quantity of water, forms "threads of the gel" that remain visible to the naked eye, deterring injection (’610 Patent, Abstract).
    • Asserted Claims: Independent claim 1 is asserted (Compl. ¶93).
    • Accused Features: Defendant's ANDA Products are alleged to contain a viscosity-increasing agent that produces the claimed gel properties upon tampering (Compl. ¶93).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are Defendant’s ANDA Products, specifically the 10 mg, 15 mg, 20 mg, 30 mg, 60 mg, and 80 mg dosage strengths of its proposed generic extended-release oxycodone hydrochloride product filed under ANDA No. 211178 (Compl. ¶¶1-2).
  • Functionality and Market Context: Defendant's ANDA Products are generic versions of Plaintiffs' OxyContin® product, an extended-release opioid analgesic for the management of severe, long-term pain (Compl. ¶2, ¶6). The act of infringement alleged is the filing of the ANDA itself under 35 U.S.C. § 271(e)(2)(A), which seeks FDA approval to market these generic products (Compl. ¶2). The complaint alleges these products, if approved, would be commercially manufactured, used, and sold in the United States (Compl. ¶48).

IV. Analysis of Infringement Allegations

'976 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An extended release abuse deterrent dosage form Defendant's ANDA Products are extended-release abuse deterrent dosage forms. ¶47 col. 2:42-51
comprising a core matrix comprising PEO having a molecular weight of from about 300,000 daltons to about 5,000,000 daltons and oxycodone or a pharmaceutically acceptable salt thereof, Defendant's ANDA Products are alleged to comprise a core matrix with PEO of the specified molecular weight and oxycodone hydrochloride. ¶47 col. 7:40-45
wherein the core matrix is heated to melt at least a portion of the PEO, The complaint alleges Defendant's ANDA Products are manufactured using a process wherein the core matrix is heated to melt at least a portion of the PEO. ¶47 col. 9:18-24
and PEG applied onto the core matrix. The complaint alleges that in Defendant's ANDA Products, PEG is applied onto the core matrix. ¶47 col. 10:1-5
  • Identified Points of Contention:
    • Scope Questions: A central question may be whether the term "abuse deterrent" requires a specific level of deterrence or covers any formulation with features intended to hinder abuse. The patent's definition, tied to forming a viscous gel, may be a key focus ('976 Patent, col. 3:1-10).
    • Technical Questions: The infringement analysis will likely depend on discovery into Defendant's actual manufacturing process. A key factual question will be whether Defendant's process includes the claimed step of "heat[ing] to melt at least a portion of the PEO" and subsequently applying PEG, as distinct from other manufacturing techniques that might achieve a similar result.

'933 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An oxycodone hydrochloride composition Defendant's ANDA Products are oxycodone hydrochloride compositions. ¶54 col. 3:35-46
having less than 25 ppm of 14-hydroxycodeinone. The complaint alleges that Defendant's ANDA Products contain the impurity 14-hydroxycodeinone at a level below the 25 ppm threshold. ¶54 col. 3:35-46
  • Identified Points of Contention:
    • Scope Questions: The claim appears definite, turning on a numerical threshold. However, disputes could arise regarding the methodology for measuring the "ppm" level, including questions of averaging, detection limits, and statistical significance.
    • Technical Questions: The core factual question is evidentiary: what is the actual, measurable level of 14-hydroxycodeinone in the Defendant's ANDA Products? The analysis will depend on analytical testing of Defendant's API and final drug product.

V. Key Claim Terms for Construction

For the '976 Patent:

  • The Term: "abuse deterrent dosage form"
  • Context and Importance: This term is central to the invention's purpose. The definition will determine whether infringement requires demonstrating a specific functional outcome (e.g., achieving a certain viscosity upon tampering) or is met by the presence of structural features intended to deter abuse.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent title, "Pharmaceutical Formulation Containing Gelling Agent", suggests the deterrence mechanism is linked to the gelling property, but the claim language itself does not explicitly require the formation of a gel with specific properties.
    • Evidence for a Narrower Interpretation: The specification repeatedly explains the abuse-deterrent function in terms of forming a "viscous gel" that is "unsuitable for injection and/or inhalation" ('976 Patent, col. 3:1-24). This language may support an interpretation where the term requires the dosage form to actually achieve this functional gelling result upon tampering.

For the '933 Patent:

  • The Term: "having less than 25 ppm of 14-hydroxycodeinone"
  • Context and Importance: This limitation defines the entire scope of the independent claim. The dispute will turn entirely on whether the accused product falls within this numerical boundary. Practitioners may focus on this term because the method of measurement can be outcome-determinative.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language itself does not specify the analytical method to be used, which could support using any scientifically valid method to measure the impurity level.
    • Evidence for a Narrower Interpretation: The patent specification provides detailed examples with specific analytical parameters, such as using High Performance Liquid Chromatography (HPLC) under defined conditions ('933 Patent, col. 27:8-48). This could support an argument that the "less than 25 ppm" limitation must be measured using the specific methodology disclosed in the patent.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement of infringement for the method claims of the '060 patent. It asserts that Defendant's proposed product label will "explicitly instruct Healthcare Providers and patients" to administer the dosage form to treat pain, which would directly infringe method of treatment claims (Compl. ¶¶ 88-89). Contributory infringement is also alleged, for example, on the basis that Defendant's products are "especially made or especially adapted for use in the infringement" of the '060 patent and have no substantial non-infringing use (Compl. ¶¶ 85-86).
  • Willful Infringement: The complaint alleges that Defendant has been aware of the existence of the patents-in-suit at least as early as the date of its Paragraph IV certifications (e.g., November 27, 2017 for the '976 and '933 patents) and "has no reasonable basis for believing" that its ANDA Products will not infringe (Compl. ¶50, ¶57). This alleged knowledge is the basis for claims of exceptional case status under 35 U.S.C. § 285.

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

This case presents two distinct categories of infringement allegations, which will likely turn on different types of evidence and legal arguments.

  • A primary issue will be one of technical implementation: For the abuse-deterrence patents (e.g., '976, '060, '582), does Ascent's manufacturing process, aimed at creating a bioequivalent generic, inherently practice the specific structural and process limitations claimed by Purdue, such as the "heating to melt" step of the '976 patent or the "at least 500 N" breaking strength of the '060 patent?
  • A second core issue will be one of analytical evidence: For the chemical purity patents (e.g., '933, '919), the dispute will focus on empirical data. What is the precise, measurable level of specified impurities in Ascent's final drug product, and does that level fall within the numerical boundaries defined by the claims? The methodology of this measurement itself may become a point of contention.