PTAB

IPR2016-01027

Amneal Pharmaceuticals LLC v. Purdue Pharma LP

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Pharmaceutical Formulation Containing Gelling Agent
  • Brief Description: The ’976 patent is directed to an oral, extended-release, abuse-deterrent dosage form of oxycodone. The formulation comprises a core matrix with polyethylene oxide (PEO) as a gelling agent to prevent abuse by injection or insufflation, and is prepared using a heating process.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claim 1 under §102 over Kumar

  • Prior Art Relied Upon: Kumar (Application # 2010/0216829).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that claim 1 of the ’976 patent is not entitled to its claimed priority date of August 6, 2001, because the priority applications fail to provide adequate written description support as required by 35 U.S.C. §112. Specifically, the priority documents do not disclose the claimed PEO molecular weight range of 300,000 to 5,000,000 daltons for use in a matrix formulation containing oxycodone. The specification only disclosed PEO in the context of osmotic dosage forms, not matrix formulations. To arrive at the claimed range, Patent Owner improperly combined a lower molecular weight range from a drug-containing "hydrogel" layer with an upper molecular weight from a separate, non-drug-containing "osmopolymer" push layer.
    • Key Aspects: Because claim 1 lacks priority support before the patent’s filing date of December 24, 2012, the Kumar publication, published on August 26, 2010, qualifies as intervening prior art. Petitioner asserted that Kumar anticipates claim 1 because Kumar’s claim 29 teaches every limitation of the challenged claim, including an extended-release, abuse-deterrent dosage form with a core matrix comprising PEO in the identical molecular weight range, magnesium stearate, and oxycodone, where the matrix is heated and PEG is applied to the core.

Ground 2: Obviousness of Claim 1 under §103 over McGinity, Joshi, and Palermo

  • Prior Art Relied Upon: McGinity (WO 97/49384), Joshi (Application # 2002/0187192), and Palermo (WO 99/32120).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that the combination of these references renders claim 1 obvious. McGinity taught hot-melt extrudable, controlled-release pharmaceutical formulations comprising a high molecular weight PEO (in a range overlapping the claimed range), a therapeutic agent (including analgesics), a lubricant like magnesium stearate, and a plasticizer like polyethylene glycol (PEG). The hot-melt extrusion process inherently involves heating to melt a portion of the PEO. Joshi taught that high molecular weight PEO acts as a gelling agent to provide abuse deterrence for drugs susceptible to abuse, addressing the very problem of injection and insufflation targeted by the ’976 patent. Finally, Palermo taught abuse-deterrent, sustained-release formulations specifically for opioids like oxycodone and disclosed preparing them in a matrix via melt-extrusion and coating them.
    • Motivation to Combine: A person of ordinary skill in the art (POSA) would have been motivated to address the well-known and growing problem of oxycodone abuse. A POSA would combine McGinity’s extended-release hot-melt extrusion platform with Joshi’s teaching of using PEO as a gelling agent to confer abuse deterrence. The known problem of opioid abuse provides the reason for this combination. Palermo further confirmed the suitability of using oxycodone in such a matrix and the desirability of creating abuse-deterrent opioid formulations.
    • Expectation of Success: A POSA would have had a high expectation of success. Combining McGinity's established formulation base with Joshi's known gelling agent (PEO) for its predictable abuse-deterrent properties would be expected to yield a formulation with both extended-release and abuse-deterrent characteristics. The properties of each component were well-known, and their combination was a predictable solution to a known market need.

4. Key Claim Construction Positions

  • "Abuse Deterrent": Petitioner argued this term, appearing only in the preamble, should be non-limiting because the claim body describes a structurally complete invention. If construed as limiting, Petitioner proposed it should mean the inclusion of any means for causing abuse deterrence, such as a gelling agent.
  • "Core Matrix Comprising A Blended Mixture": Petitioner argued this term was not defined in the specification and lacked support in the original application. This lack of support was central to the priority date challenge in Ground 1. Petitioner proposed the term should be construed as defined by the claim itself: a blended mixture of the specified PEO, magnesium stearate, and oxycodone.
  • "Core Matrix Is Heated To Melt...": Petitioner argued the broadest reasonable interpretation of this limitation is the application of heat via conventional melt-granulation or melt-extrusion, as described in the specification.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claim 1 of the ’976 patent as unpatentable under 35 U.S.C. §§ 102 and 103.