Ethicon Inc v. Board Of Regents University Of Texas System

1. Case Identification

• Case #: IPR2019-00406
• Patent #: 6,596,296
• Filed: December 7, 2018
• Petitioner(s): Ethicon, Inc.
• Patent Owner(s): Board of Regents, The University of Texas System
• Challenged Claims: 1, 4, 11, 16-17, 20, and 26

2. Patent Overview

• Title: Drug Releasing Biodegradable Fiber Implant
• Brief Description: The ’296 patent discloses compositions for drug delivery using a biodegradable polymer fiber. The core inventive concept purports to be that the fiber is composed of two separate, "immiscible" phases: a first polymer phase and a second phase comprising one or more therapeutic agents.

3. Grounds for Unpatentability

Ground 1: Claims 1, 11, 16-17, and 26 are anticipated or obvious over Song.

• Prior Art Relied Upon: Song (Patent 5,364,627).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Song, which was not considered during prosecution, anticipates every limitation of the challenged claims. Song described a drug delivery system in the form of a "fiber" made from a "biodegradable polymer" wall material and an "active agent" (drug). Crucially, Song explicitly stated that the polymer wall material and the dispersed active agent "must be immiscible with each other." Petitioner asserted this directly taught the key limitations of claim 1: a biodegradable polymer fiber (first phase) with a dispersed drug (second phase), where the two phases are immiscible.
  • Prior Art Mapping (Dependent Claims): Petitioner contended that Song also disclosed the limitations of the dependent claims. Song taught using "anti-inflammatory substances" and "anti-coagulants" (claim 11), using aliphatic polyesters like copolymers of lactic and glycolic acid (claims 16-17), and a system for the "gradual release" of an agent, which inherently results in varying release rates over time as drug particles of different sizes and locations are exposed (claim 26).
  • Expectation of Success: For the obviousness assertion regarding claim 26, Petitioner argued a person of ordinary skill in the art (POSA) would understand that the matrix system described in Song, with dispersed drug particles, would necessarily release the drug at varying rates over time. This was a well-known characteristic of such systems.

Ground 2: Claim 4 is obvious over Song in view of Billmeyer or Curatolo.

• Prior Art Relied Upon: Song (Patent 5,364,627), Billmeyer (a 1971 textbook chapter on fiber technology), and Curatolo (European Patent App. Pub. No. 0253554).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed dependent claim 4, which required the drug-releasing fiber of claim 1 to be "woven, braided or knitted in an assembly." Petitioner argued that while Song disclosed the base fiber of claim 1, applying well-known textile techniques to form an assembly would have been obvious. Billmeyer, a standard textbook incorporated by reference in Song, explicitly taught transforming fibers into fabric via weaving, knitting, and braiding. Curatolo, a reference in a similar field, also taught that drug-containing fibers can be braided to increase surface area.
  • Motivation to Combine: A POSA would combine Song's drug-releasing fiber with the teachings of Billmeyer or Curatolo for known benefits. These techniques were described as standard processes for forming fibers into more useful structures. Specifically, Billmeyer taught that braiding increases tensile strength, and Curatolo taught that braiding increases the surface area, which is advantageous for drug delivery.
  • Expectation of Success: Petitioner asserted a high expectation of success, as weaving, braiding, and knitting were simple, textbook techniques for manipulating polymer fibers. The ’296 patent itself provided no specific teachings on these methods, acknowledging them as art-known.

Ground 3: Claims 1, 4, 11, 16-17, 20, and 26 are anticipated or obvious over Choi.

• Prior Art Relied Upon: Choi (Patent 4,093,709).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner presented Choi as an alternative primary reference that anticipated or rendered obvious all challenged claims. Choi, not considered during prosecution, disclosed drug delivery devices made from bioerodible polymers that can be "spun into fibers." Choi's Figure 5 showed an embodiment where drug-containing "cells" are dispersed in a polymer matrix, with the drug dissolved in a liquid that is a "nonsolvent for the polymer." Petitioner argued this structure met the "immiscible" phases limitation. Figure 6 showed drug-filled microcapsules dispersed in the polymer, which were also argued to be an immiscible second phase.
  • Prior Art Mapping (Dependent Claims): Petitioner argued Choi also met the dependent claim limitations. Choi disclosed fibers "intertwisted" with other fibers (claim 4), the use of "anti-inflammatory agents" (claim 11), polymers that were poly(ortho esters) (claim 16), multilayered fiber structures (claim 20), and materials that were "rate controlling" to provide a "variable rate" of release (claim 26).
  • Motivation to Combine: For any elements arguably not explicitly disclosed (e.g., using specific polymers like poly(glycolic acid) for claim 17), Petitioner argued a POSA would have been motivated to use these well-known, optimal polymers for their known biocompatibility and predictable degradation, as taught by other references.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 4 and 20 are obvious over Song combined with general POSA knowledge, and that claim 20 is obvious over Song in view of Sidman (Patent 4,351,337) for its teachings on multilayered fibers to control drug release.

4. Key Claim Construction Positions

• Petitioner adopted the constructions from a related district court action. The constructions were central to the invalidity arguments.
• "first phase" / "second phase": Construed as "the polymer portion of the fiber" and "the discrete drug-containing regions dispersed throughout the fiber," respectively. This framed the invention as a simple drug/polymer matrix.
• "immiscible": Construed as "incapable of dissolving into one another." Petitioner emphasized this absolute definition was critical. It argued that Patent Owner inserted this absolute term during prosecution to overcome rejections based on prior art that showed drug/polymer mixtures, and therefore should be held to its strict meaning. Petitioner argued that prior art like Song (which "must be immiscible") and Choi (using a "nonsolvent for the polymer") explicitly met this absolute requirement.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise discretionary denial. The petition was filed concurrently with a petition against a related patent. Petitioner noted that in the co-pending district court litigation, the case was stayed for all proceedings other than claim construction. It was argued that no fact or expert discovery had occurred and no trial date had been set, meaning an inter partes review (IPR) would be more efficient and would not be duplicative of advanced district court proceedings.

6. Relief Requested

• Petitioner requested the institution of an IPR and the cancellation of claims 1, 4, 11, 16-17, 20, and 26 of the ’296 patent as unpatentable.