PTAB

IPR2014-01320

WL Gore & Associates Inc v. LifePort Sciences LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: ENDOLUMINAL PROSTHESIS AND SYSTEM FOR JOINING
  • Brief Description: The ’167 patent discloses an endoluminal prosthesis system for joining two stents together within a body lumen to form a continuous passage. The system uses a "male engaging portion" on one stent that inserts into and expands within a "female cooperating portion" on a second stent to resist longitudinal separation, with configurations for bifurcated vessels.

3. Grounds for Unpatentability

Ground 1: Obviousness over Cragg and Schaer - Claims 1, 3, 13-20, 24-28, 30, 31, 33-40, 44-48, 50, 52-60, 64-68, 70, and 71 are obvious over Cragg in view of Schaer.

  • Prior Art Relied Upon: Cragg (Patent 5,405,377) and Schaer (a 1992 article in Gastrointestinal Endoscopy).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Cragg disclosed the fundamental covered stent structure recited in the claims, including the use of shape memory nitinol alloy, zig-zag wire configurations, and attached graft layers to make the stent fluid-tight. However, Cragg did not explicitly teach joining two such stents. Schaer allegedly supplied this missing element by teaching a method of overlapping two self-expanding, covered esophageal stents to extend their length or repair defects. Petitioner contended that Schaer’s technique of inserting one stent into another directly corresponds to the claimed "male engaging portion" and "female portion" that inter-engage to form a stent joining means. Schaer also disclosed using flared ends ("flanges") and barbs ("hooks") for anchoring, which Petitioner mapped to dependent claims reciting these features.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Cragg and Schaer to apply the known and advantageous stent-joining technique from Schaer to the superior, flexible, shape-memory alloy stent design of Cragg. The combination would address the common clinical needs of extending stent length or repairing graft defects, achieving predictable results by combining known elements for their intended purposes.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because the combination involved applying a known technique (overlapping stents) to a known device (covered stent) to achieve a predictable outcome (a longer, joined stent system).

Ground 2: Obviousness over Cragg, Schaer, and Pinchuk - Claims 2, 4, and 51 are obvious over Cragg in view of Schaer and Pinchuk.

  • Prior Art Relied Upon: Cragg (Patent 5,405,377), Schaer (a 1992 journal article), and Pinchuk (Patent 5,226,913).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the Cragg/Schaer combination from Ground 1 and added Pinchuk to teach the limitations of claims 2, 4, and 51, which required a tapered or frustoconical female portion. While Cragg and Schaer provided the basic joined-stent system, Pinchuk explicitly disclosed making endoprostheses with "tapered, truncated cone-shaped" (i.e., frustoconical) designs.
    • Motivation to Combine: Petitioner asserted a POSITA would be motivated to modify the Cragg/Schaer stent system with the tapered design taught by Pinchuk for known benefits. These benefits included better tracking the natural tapering shape of a blood vessel or enhancing the fixation of the joined stents, similar to how Schaer used flanges for anchoring.
    • Expectation of Success: Incorporating a known tapered shape into a stent design was a simple and predictable modification that a POSITA would expect to successfully implement.

Ground 3: Obviousness over Cragg, Schaer, and Lazarus - Claims 5-12, 29, 49, 69, and 72-79 are obvious over Cragg in view of Schaer and Lazarus.

  • Prior Art Relied Upon: Cragg (Patent 5,405,377), Schaer (a 1992 journal article), and Lazarus (Patent 5,871,536).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addressed claims directed to bifurcated prosthesis systems. Petitioner argued the Cragg/Schaer combination taught joining stents generally, but Lazarus provided the specific teachings for a bifurcated application. Lazarus disclosed a self-expanding, bifurcated intraluminal graft with a main tubular body and two legs for treating bifurcated vessels. Petitioner asserted this structure directly taught the claimed "two transversely spaced female portions" of a second endoluminal stent adapted to extend across a vessel bifurcation.
    • Motivation to Combine: Lazarus expressed a desire to be able to adjust the length of the legs of its bifurcated endoprosthesis. A POSITA would be motivated to combine the stent-joining technique of Schaer with the bifurcated structure of Lazarus to achieve this adjustability. This would allow a surgeon to extend the length of one or both legs of the bifurcated stent in vivo by overlapping an additional stent (as taught by Cragg/Schaer), providing a customizable solution for treating bifurcated vessels.
    • Expectation of Success: A POSITA would expect that applying a known stent-overlapping method to the legs of a known bifurcated stent graft would successfully result in a longer, functional bifurcated prosthesis.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations incorporating Wolff (Patent 4,830,003) for its teachings on radiopaque markers to aid in fluoroscopic positioning, and Dumon (Patent 5,236,446) as an alternative reference for a bifurcated prosthesis system.

4. Key Claim Construction Positions

  • "stent joining means for joining...": Petitioner argued this phrase in the preamble of claims 1-12 and 72-82 was not a means-plus-function limitation under pre-AIA §112, paragraph 6. Instead, it was a statement of intended use for the subsequently recited structural components (male/female portions), which were sufficient to define the invention.
  • "endoluminal prosthesis": Petitioner proposed this term be construed as "a stent with a graft layer," based on the patent's specification.
  • "shape memory alloy": Petitioner proposed this term be construed as an "alloy that recovers original shape on being raised to a higher temperature," consistent with the disclosure of nitinol.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of all claims 1-82 of the ’167 patent as unpatentable.