PTAB

IPR2016-01028

Amneal Pharmaceuticals LLC v. Purdue Pharma LP

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Key Events
Petition
petition

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 the opioid analgesic oxycodone. The formulation comprises a core matrix containing polyethylene oxide (PEO) as a gelling agent, which is intended to thwart abuse by injection or insufflation.

3. Grounds for Unpatentability

Ground 1: Obviousness over Palermo, the Handbook, and McGinity - Claim 1 is obvious over Palermo in view of the Handbook of Pharmaceutical Excipients and McGinity.

  • Prior Art Relied Upon: Palermo (International Publication No. WO 99/32120), The Handbook of Pharmaceutical Excipients (3rd ed. 2000) ("Handbook"), and McGinity (International Publication No. WO 97/49384).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Palermo taught all key elements of the claimed invention except for the specific identity and properties of the hydrophilic polymer. Palermo disclosed an abuse-deterrent, extended-release dosage form for opioids like oxycodone, comprising a core matrix with a hydrophilic material, magnesium stearate, and a coating that could include polyethylene glycol (PEG). Petitioner argued that a person of ordinary skill in the art (POSA) would have consulted the Handbook, a standard industry reference, to select a suitable hydrophilic material and would have been led directly to PEO. The Handbook allegedly identified PEO within the claimed molecular weight range (300,000 to 5,000,000 daltons) as ideal for extended-release hydrophilic matrix formulations. To meet the claim’s "heating" limitation, Petitioner pointed to McGinity, which taught preparing PEO-based analgesic matrices using hot-melt extrusion, a process involving heating to melt the PEO.
    • Motivation to Combine: A POSA seeking to implement Palermo’s abuse-deterrent formulation would be motivated to select a well-known and effective hydrophilic polymer. The Handbook expressly taught using higher molecular weight PEO to achieve delayed drug release via a hydrophilic matrix. Palermo itself taught that its matrices could be prepared via melt-extrusion. A POSA would therefore be motivated to look to a reference like McGinity, which explicitly taught the hot-melt extrusion of PEO-based analgesic formulations, to optimize the manufacturing process.
    • Expectation of Success: Petitioner contended that a POSA would have a reasonable expectation of success because the combination involved using known components for their predictable properties. PEO was well-known for providing extended release and gelling, and hot-melt extrusion was a conventional method for preparing such matrices.

Ground 2: Obviousness over McGinity, Joshi, Bastin, and the PDR - Claim 1 is obvious over McGinity in view of Joshi, Bastin, and the Physicians’ Desk Reference.

  • Prior Art Relied Upon: McGinity (WO 97/49384), Joshi (U.S. Patent Application Publication No. 2002/0187192), Bastin (International Publication No. WO 95/20947), and the Physicians’ Desk Reference (53rd ed. 1999) ("PDR").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that McGinity taught a controlled-release dosage form made by hot-melt extruding a blended mixture of high molecular weight PEO, an analgesic, magnesium stearate, and PEG (as a plasticizer), thus teaching nearly every limitation of claim 1. While McGinity did not explicitly name oxycodone, Petitioner noted that courts had previously found McGinity's disclosure of "analgesics" to encompass oxycodone. Joshi taught that using PEO in the claimed molecular weight range as a gelling agent in a drug formulation provided abuse-deterrent properties against injection and snorting. The PDR was cited to confirm that oxycodone was a widely abused opioid commonly formulated for extended release. Bastin taught film-coating tablets with PEG and acknowledged that gelling agents could be used to create sustained-release products.
    • Motivation to Combine: The motivation was to address the well-known public health problem of oxycodone abuse. A POSA starting with McGinity’s extended-release PEO-based formulation for an analgesic would be motivated to incorporate abuse-deterrent features. Joshi provided the explicit reason to do so, teaching that the very same PEO used by McGinity imparted the desired gelling and abuse-deterrent properties. The PDR established oxycodone as a prime candidate for such a formulation. Bastin further reinforced the concept that gelling agents were compatible with, and could even provide, extended-release characteristics.
    • Expectation of Success: A POSA would have a high expectation of success because Joshi taught that the abuse-deterrent property was an inherent result of using the high molecular weight PEO already present in McGinity's formulation. Combining the teachings would simply be recognizing an additional, inherent benefit (abuse deterrence) of an existing extended-release formulation and applying it to a known drug of abuse (oxycodone).

4. Key Claim Construction Positions

  • "Abuse Deterrent": Petitioner argued this term, appearing only in the preamble, should be non-limiting because the claim body described a structurally complete invention without attributing abuse deterrence to any specific element. Alternatively, if limiting, it should be broadly construed as the inclusion of any means for causing abuse deterrence, such as a gelling agent.
  • "Core Matrix Is Heated To Melt At Least A Portion Of The PEO...": Petitioner proposed this should be construed as the application of heat via conventional techniques like melt-granulation or melt-extrusion. This construction was based on the specification’s examples and arguments made during prosecution to overcome an indefiniteness rejection.
  • "PEG applied onto the core matrix": Petitioner contended this meant PEG is placed on or in contact with the core matrix, which could occur before, during (e.g., as a plasticizer in an extruder), or after the matrix is heated (e.g., as a film coating).

5. Relief Requested

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