PTAB

IPR2019-00407

Ethicon Inc v. Board Of Regents University Of Texas System

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1. Case Identification

2. Patent Overview

  • Title: Drug Releasing Biodegradable Fiber for Delivery of Therapeutics
  • Brief Description: The ’603 patent describes drug delivery compositions comprising fibers made of at least two components: a biodegradable polymer and a gel or hydrogel. The compositions are intended for applications in tissue engineering and controlled drug release.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 6, 11, 13, and 19 are anticipated or, in the alternative, obvious over Groves.

  • Prior Art Relied Upon: Groves (Patent 5,186,936).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Groves, a reference not considered during prosecution, discloses every limitation of the challenged claims. Groves teaches a drug delivery packing material in a "fibrous form" for treating infections. This fiber is a bi-component structure with an "outer coating" (wall) made of biodegradable polymers (e.g., pectin, chitosan) and an "inner core" (bore or lumen) that contains a hydrogel loaded with an antibiotic ester. This structure directly maps to the limitations of independent claim 1. Petitioner further asserted that Groves discloses the specific arrangements of dependent claim 2 and the therapeutic agent requirements of claims 6, 11, and 13, including the use of a hydrophobic drug (metronidazole palmitate). For independent claim 19, Petitioner contended that Groves' fiber, being made of a hydrogel, anticipates the claim's requirement for a fiber comprising an emulsion consisting essentially of a gel or hydrogel.
    • Key Aspects: A central point of Petitioner's argument was that the Patent Owner, during prosecution of the European counterpart to the ’603 patent, conceded that Groves disclosed all elements of a corresponding claim. To overcome Groves, the Patent Owner was forced to amend the European claims to add a limitation requiring that the "concentration of the gel or the hydrogel varies as a function of distance along the long axis of the fiber"—a limitation absent from the challenged U.S. claims. Petitioner presented this as an admission of anticipation.

Ground 2: Claim 19 is anticipated or, in the alternative, obvious over Sirkar.

  • Prior Art Relied Upon: Sirkar (International Publication No. WO 95/23598).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sirkar anticipates independent claim 19, which recites a drug delivery fiber comprising an "emulsion consisting essentially of a gel or hydrogel." Sirkar, also not considered during prosecution, discloses a controlled release device using "microporous hollow fibers." Critically, Sirkar explicitly states that the "membrane" of the hollow fiber itself may be a "hydrogel." Petitioner contended that because the entire material of the fiber's membrane is a hydrogel, Sirkar discloses a fiber "consisting essentially of a... hydrogel," thereby anticipating claim 19 under the district court's claim construction.
    • Motivation to Combine (for §103 grounds): As an alternative, Petitioner argued that even under the Patent Owner's proposed (and rejected) claim construction requiring a dispersed gel phase, the claim would be obvious. Sirkar teaches that it is preferred to gel the water or solvent within the pores of the fiber wall. A person of ordinary skill in the art (POSA) would have been motivated to apply this teaching to create a fiber with a dispersed gel phase to control drug release, with a reasonable expectation of success.

Ground 3: Claims 1, 2, and 13 are anticipated or, in the alternative, obvious over Vacanti.

  • Prior Art Relied Upon: Vacanti (Patent 5,759,830).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Vacanti anticipates claims 1, 2, and 13 by teaching cell-scaffold compositions for tissue engineering. Vacanti’s scaffold is composed of fibers made from a biodegradable synthetic polymer (the first component). To enhance cell attachment, Vacanti teaches coating these polymer fibers with materials such as cross-linked gelatin (the second component), which Petitioner noted is a gel. This creates a bi-component fiber with a biodegradable polymer bore and a gel wall, meeting the limitations of claims 1 and 2. Vacanti also expressly teaches that "drugs can be incorporated into the matrix," including classes of drugs known to be hydrophobic (e.g., immunomodulators), thus anticipating claim 13.
    • Motivation to Combine (for §103 grounds): In the alternative, Petitioner argued it would have been obvious to a POSA to use a hydrophobic drug in Vacanti's system. Vacanti discloses drug classes (such as immunomodulators) that were well-known to include hydrophobic compounds. A POSA would have been motivated to select a hydrophobic drug for its therapeutic properties and would have had a reasonable expectation of successfully incorporating it into Vacanti's coated fiber system to achieve controlled release.

4. Key Claim Construction Positions

  • Petitioner adopted the claim constructions from a parallel district court litigation for key terms, arguing the claims are unpatentable even under these constructions.
  • "hydrogel": "a colloid in which a dispersed phase (colloid) is combined with a continuous phase (water) to produce a viscous jellylike product."
  • "gel": "a colloidal system with at least two phases, one of which forms a continuous three-dimensional network that acts as an elastic solid."
  • "an emulsion consisting essentially of a gel or hydrogel" (Claim 19): "an emulsion having only the following material elements: a gel or hydrogel." This construction was critical for the anticipation arguments against claim 19, as it means the fiber itself can be the hydrogel.

5. Arguments Regarding Discretionary Denial

  • Petitioner noted that in the parallel district court action, no discovery had been taken and no trial date had been set at the time of filing. This argument was presented to preemptively counter potential discretionary denial under Fintiv factors by highlighting the early stage of the co-pending litigation.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 2, 6, 11, 13, and 19 of the ’603 patent as unpatentable.