DCT

1:18-cv-00083

Purdue Pharma LP v. Ascent Pharma Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:18-cv-00083, D. Del., 01/11/2018
  • Venue Allegations: Plaintiffs allege venue is proper because a related corporate entity, Camber Pharmaceuticals, Inc., is incorporated in Delaware and operates as an "integrated, unitary business" with Defendant Ascent.
  • Core Dispute: Plaintiffs allege that Defendant’s filing of an Abbreviated New Drug Application (ANDA) to market a generic version of the extended-release opioid analgesic OxyContin® constitutes an act of infringement of seven patents related to the drug's formulation, purity, and abuse-deterrent properties.
  • Technical Context: The technology concerns pharmaceutical formulations of oxycodone, a potent opioid, with features designed to prevent common methods of abuse, such as crushing for injection or snorting.
  • Key Procedural History: The complaint notes that U.S. Patent No. 8,309,060 was previously found infringed but invalid for obviousness in a separate litigation involving a different product (Opana® ER). An appeal of that invalidity judgment was pending at the time of this complaint's filing, and Plaintiffs assert that collateral estoppel should not apply.

Case Timeline

Date Event
2001-08-06 Priority Date for ’976 and ’582 Patents
2002-06-17 Priority Date for ’610 Patent
2003-08-06 Priority Date for ’060 Patent
2004-03-30 Priority Date for ’933 and ’919 Patents
2012-11-13 ’060 Patent Issued
2013-02-05 Priority Date for ’533 Patent
2015-06-23 ’976 Patent Issued
2015-07-07 ’933 Patent Issued
2015-10-06 ’533 Patent Issued
2016-12-20 ’919 Patent Issued
2017-03-27 Appeal Briefed in Prior Litigation of ’060 Patent
2017-06-13 ’610 Patent Issued
2017-11-27 Defendant Files ANDA No. 211178 and Paragraph IV Notice Letter
2018-01-09 ’582 Patent Issued
2018-01-11 Complaint Filed

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

No probative visual evidence provided in complaint.

U.S. Patent No. 9,060,976 - "PHARMACEUTICAL FORMULATION CONTAINING GELLING AGENT"

The Invention Explained

  • Problem Addressed: The patent addresses the abuse of oral opioid formulations, which are often crushed by abusers to extract the active ingredient with a solvent for subsequent injection, bypassing the controlled-release mechanism to achieve a rapid euphoric effect (’976 Patent, col. 1:16-24).
  • The Patented Solution: The invention is an extended-release dosage form containing a gelling agent, such as polyethylene oxide (PEO). If an abuser crushes the tablet and mixes it with a small amount of liquid, the formulation forms a viscous gel that is difficult or impossible to draw into a syringe for injection (’976 Patent, col. 3:2-14). The claimed formulation also involves heating the core matrix to melt at least a portion of the PEO and applying polyethylene glycol (PEG) onto the core, a process intended to create the abuse-deterrent properties (’976 Patent, col. 17:1-6).
  • Technical Importance: This gelling technology represents a physical barrier approach to abuse deterrence, aiming to frustrate the common abuse pathway of extraction and injection without adding an antagonist drug. (Compl. ¶ 39).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶ 39).
  • Essential elements of claim 1 include:
    • An extended release abuse deterrent dosage form comprising a core matrix.
    • The core matrix comprises PEO with a molecular weight from about 300,000 to 5,000,000 daltons and oxycodone.
    • The core matrix is heated to melt at least a portion of the PEO.
    • PEG is applied onto the core matrix.
  • The complaint does not explicitly reserve the right to assert dependent claims for the ’976 Patent.

U.S. Patent No. 9,073,933 - "OXYCODONE HYDROCHLORIDE HAVING LESS THAN 25 PPM 14-HYDROXYCODEINONE"

The Invention Explained

  • Problem Addressed: The synthesis of oxycodone from thebaine can produce unwanted byproducts, including an alpha, beta, unsaturated ketone known as 14-hydroxycodeinone. Commercially available oxycodone active pharmaceutical ingredient (API) at the time contained levels of this impurity greater than 100 parts per million (ppm) (’933 Patent, col. 2:1-22).
  • The Patented Solution: The patent discloses a process for preparing oxycodone hydrochloride that results in a final composition with a very low level of the 14-hydroxycodeinone impurity—specifically, less than 25 ppm. The process involves hydrogenation steps designed to reduce this specific impurity from the final API (’933 Patent, col. 2:29-34).
  • Technical Importance: This invention provides a higher-purity form of the oxycodone API, which may be relevant for product safety, stability, and meeting stringent regulatory requirements. (Compl. ¶ 46).

Key Claims at a Glance

  • The complaint asserts independent claim 1, among others (Compl. ¶ 46).
  • The essential element of claim 1 is:
    • An oxycodone hydrochloride composition having less than 25 ppm of 14-hydroxycodeinone.
  • The complaint reserves the right to assert other claims of the ’933 patent (Compl. ¶ 47).

U.S. Patent No. 9,522,919 - "OXYCODONE COMPOSITIONS"

  • Technology Synopsis: This patent, related to the ’933 Patent, claims an oxycodone hydrochloride composition with a low level of a different impurity. It addresses the need for high-purity oxycodone API by controlling for the presence of 8α,14-dihydroxy-7,8-dihydrocodeinone.
  • Asserted Claims: Independent claim 1 (Compl. ¶ 53).
  • Accused Features: Defendant's ANDA Product is alleged to be a composition wherein the ratio of the specified impurity to oxycodone hydrochloride is 0.04% or less as measured by HPLC (Compl. ¶ 53).

U.S. Patent No. 9,149,533 - "TAMPER RESISTANT PHARMACEUTICAL FORMULATIONS"

  • Technology Synopsis: This patent describes a solid oral dosage form designed to be tamper-resistant. The claimed solution combines a heat-labile gelling agent (which loses viscosity upon heating), a thermal stabilizer to counteract that effect, a pH modifying agent, and a drug susceptible to abuse.
  • Asserted Claims: Independent claim 1 (Compl. ¶ 60).
  • Accused Features: Defendant's ANDA Product is alleged to comprise the claimed combination of a heat-labile gelling agent, a thermal stabilizer, an abusable drug, and a pH modifying agent (Compl. ¶ 60).

U.S. Patent No. 9,861,582 - "PHARMACEUTICAL FORMULATION CONTAINING GELLING AGENT"

  • Technology Synopsis: This patent claims a method for preparing an abuse-deterrent, controlled-release dosage form. The method involves preparing a matrix with oxycodone and a specific PEO gelling agent, applying a coating of polyvinyl alcohol, and ensuring the final form creates a gel when tampered with, provides a 12-hour therapeutic effect, and contains oxycodone as the sole active agent.
  • Asserted Claims: Independent claim 1 (Compl. ¶ 66).
  • Accused Features: The manufacture of Defendant's ANDA Product is alleged to meet the specific method steps and achieve the functional properties recited in the claim (Compl. ¶ 66).

U.S. Patent No. 8,309,060 - "ABUSE-PROOFED DOSAGE FORM"

  • Technology Synopsis: This patent addresses abuse by creating a dosage form with high mechanical resistance to crushing. The invention uses a thermoforming process with a high molecular weight polymer to achieve a breaking strength of at least 500 Newtons, making it difficult to pulverize with conventional means.
  • Asserted Claims: Independent claim 1 and method claim 28 (Compl. ¶¶ 72, 78).
  • Accused Features: Defendant's ANDA Product is alleged to be a thermoformed dosage form with an active ingredient and a high molecular weight polymer that results in a breaking strength of at least 500 N (Compl. ¶ 72).

U.S. Patent No. 9,675,610 - "ABUSE-PROOFED DOSAGE FORM"

  • Technology Synopsis: This patent, related to the ’060 Patent, focuses on preventing parenteral abuse. It claims a solid dosage form with a viscosity-increasing agent that, when crushed and mixed with water, forms a gel that is difficult to draw into a hypodermic needle and, if injected into more water, forms visible "threads," acting as a visual deterrent.
  • Asserted Claims: Independent claim 1 (Compl. ¶ 83).
  • Accused Features: Defendant's ANDA Product is alleged to contain a viscosity-increasing agent that produces the claimed gel and visible thread properties upon tampering (Compl. ¶ 83).

III. The Accused Instrumentality

Product Identification

  • Defendant's ANDA Product, identified as pertaining to ANDA No. 211178, which seeks FDA approval to market a generic version of Purdue's OxyContin® brand extended-release oxycodone hydrochloride in a 40 mg dosage strength (Compl. ¶¶ 1-2).

Functionality and Market Context

  • The complaint alleges infringement based on the act of filing the ANDA under 35 U.S.C. § 271(e)(2)(A), which seeks approval for a product that is bioequivalent to OxyContin® (Compl. ¶ 33). The complaint does not provide specific details on the composition or manufacturing process of the proposed generic product, instead alleging on "information and belief" that the product, if approved and marketed, would meet the limitations of the asserted patents (Compl. ¶ 39, 46). The accused product targets the market for long-term, around-the-clock opioid treatment for severe pain (Compl. ¶ 2).

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 comprising a core matrix The complaint alleges on information and belief that Defendant's ANDA Product is an extended release abuse deterrent dosage form. ¶39 col. 24:34-36
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 The complaint alleges the ANDA product contains a PEO within the claimed molecular weight range and oxycodone. ¶39 col. 24:37-40
wherein the core matrix is heated to melt at least a portion of the PEO The complaint alleges that the manufacturing process for the ANDA product includes heating the core matrix to melt the PEO. ¶39 col. 24:41-42
and PEG applied onto the core matrix The complaint alleges that the ANDA product has PEG applied onto its core matrix. ¶39 col. 17:1-6

'933 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
an oxycodone hydrochloride composition having less than 25 ppm of 14-hydroxycodeinone The complaint alleges on information and belief that Defendant's ANDA product is a composition containing less than 25 ppm of the specified impurity. ¶46 col. 35:1-3

Identified Points of Contention

  • Evidentiary Questions: The complaint's allegations are made on "information and belief" and are conclusory. A central point of contention will be factual, hinging on what discovery reveals about the actual formulation, API purity, and manufacturing process of Ascent's proposed generic product.
  • Technical Questions: For the ’976 patent, a key question will be whether Ascent's manufacturing process involves a step that meets the "heated to melt at least a portion of the PEO" limitation. For the chemistry patents (’933 and ’919), the dispute will focus on whether the API used by Ascent meets the specific impurity profiles claimed. For the mechanical property patents (’060 and ’610), the dispute will concern whether Ascent's product exhibits the claimed breaking strength or gelling characteristics when tested.

V. Key Claim Terms for Construction

"heated to melt at least a portion of the PEO" (’976 Patent, Claim 1)

  • Context and Importance: This term describes a process step in a product-by-process claim. The infringement analysis for the ’976 patent may turn on whether Ascent’s manufacturing process includes a step that falls within the scope of this limitation. Practitioners may focus on this term because it links the final product's properties to a specific manufacturing action.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The plain language of the claim does not specify a particular temperature, duration, or method of heating, which could support an argument that any heating step during formulation that causes any melting of the PEO is sufficient to infringe (’976 Patent, col. 24:41-42).
    • Evidence for a Narrower Interpretation: The specification describes specific embodiments and examples where heating is performed in a particular manner (e.g., using a "melt-extrusion" process) to achieve the abuse-deterrent properties (’976 Patent, col. 17:1-6). A defendant may argue that the term should be limited to the types of heating processes disclosed that are essential to the invention's function.

"breaking strength of at least 500 N" (’060 Patent, Claim 1)

  • Context and Importance: This term defines a key functional and objective property of the abuse-proofed dosage form. Infringement will depend on whether the accused product meets this specific threshold of crush resistance when measured.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The complaint does not provide sufficient detail for analysis of this element.
    • Evidence for a Narrower Interpretation: The patent specification provides a detailed, specific "Method for Determining Breaking Strength," referencing a particular apparatus and the European Pharmacopoeia test method (’060 Patent, col. 17:1-26). This explicit definition provides strong intrinsic evidence that may limit disputes to whether the accused product meets the threshold when subjected to this exact testing protocol.

VI. Other Allegations

Indirect Infringement

  • The complaint alleges that if the ANDA is approved, Ascent's commercial manufacture, use, and sale of the generic product will induce infringement by end-users and contribute to infringement (Compl. ¶¶ 40, 47, 54, 61, 67, 73, 84). For the ’060 patent, it specifically alleges that the proposed product label will explicitly instruct healthcare providers and patients to use the product in a manner that directly infringes method claim 28 (Compl. ¶ 78).

Willful Infringement

  • For each asserted patent, the complaint alleges that Ascent has been aware of the patent "at least as early as the date of Defendant's Paragraph IV certification" and has no reasonable basis for believing its product will not infringe (Compl. ¶¶ 42, 49, 56, 86). On this basis, Plaintiffs request a declaration that the case is "exceptional" and an award of attorneys' fees (Compl. p. 19, ¶ D).

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

  • A core issue will be one of factual proof: given that infringement is alleged based on the filing of an ANDA, the case will depend on what discovery reveals about the specific formulation, API characteristics, and manufacturing process of Ascent's proposed generic product and whether they align with the patent claims.
  • A dispositive question will be the preclusive effect of prior litigation: will the court find that the prior invalidity judgment against the ’060 patent in the Endo case collaterally estops Plaintiffs from re-litigating its validity here, or will Plaintiffs succeed in their argument that they lacked a "full and fair opportunity" to defend the patent in the earlier case?
  • A key technical question will be one of functional and compositional equivalence: for the array of patents-in-suit, the central disputes will be whether Ascent's product possesses the specific chemical purity profiles (e.g., <25 ppm of an impurity), mechanical properties (e.g., >500 N breaking strength), and abuse-deterrent functionalities (e.g., gelling into visible threads) required by the claims.