PTAB

IPR2015-01722

EndoLogix Inc v. LifePort Sciences LLC

Key Events

Petition

petition Intelligence

Title: Endoluminal Prosthesis (Stent)
Brief Description: The ’482 patent relates to an endoluminal prosthesis for use in a blood vessel. The technology centers on a stent constructed from a filament formed into a plurality of interconnected, non-helical hoops, where the plane of each hoop is substantially perpendicular to the longitudinal axis of the stent.

Prior Art Relied Upon: Ryan (Patent 8,317,854).
Core Argument for this Ground: Petitioner argued that Ryan, which discloses a bifurcated stent-graft for treating aneurysms, teaches every element of the challenged claims. The central assertion was that Ryan's preferred embodiment describes a non-helical stent structure that meets all limitations of independent claims 1 and 30, as well as the additional limitations of the challenged dependent claims.
- Prior Art Mapping: Petitioner asserted that Ryan discloses a tubular frame comprising a plurality of non-helical "band or ring structures" (hoops) oriented in a plane perpendicular to the stent's longitudinal axis, directly corresponding to limitations in claim 1. For the "means for securing" limitation, Petitioner contended that Ryan's "bridge element 13," which joins adjacent hoops, is a structural equivalent that performs the identical claimed function. For dependent claims, Petitioner mapped Ryan's disclosure of bifurcated designs and segments with varying properties to claims 2-9 and 12, its "continuous circular ring" to claim 13, its fabric "outer liner" to claim 22, and its overall structure to the elements of independent claim 30.

Prior Art Relied Upon: Ryan (Patent 8,317,854), Cragg (Patent 5,405,377).
Core Argument for this Ground: In the alternative to its anticipation argument, Petitioner contended that if Ryan’s "bridge elements" were not deemed structurally equivalent to the securing means disclosed in the ’482 patent, it would have been obvious for a person of ordinary skill in the art (POSITA) to modify Ryan’s stent using the explicit securing structures taught by Cragg.
- Prior Art Mapping: Ryan was relied upon for its disclosure of the fundamental non-helical stent structure with abutting apices. Cragg, which discloses a helical stent, was cited for its teaching of using "loop members," sutures, staples, or rings to connect adjacent apices.
- Motivation to Combine: A POSITA would combine the references to achieve the predictable result of a stable stent structure with enhanced strength. Petitioner argued this was merely a simple substitution of one well-known securing means (Cragg's loops/sutures) for another (Ryan's integral bridges) to perform the identical, well-known function of connecting adjacent stent hoops.
- Expectation of Success: A POSITA would have had a high expectation of success, as both references operate in the same field of stent design, and securing adjacent apices to provide support was a common and understood practice.

Prior Art Relied Upon: Hillstead (Patent 5,135,536).
Core Argument for this Ground: Petitioner presented Hillstead as an independent primary reference that anticipates most of the challenged claims. Hillstead discloses a non-helical cylindrical stent design that Petitioner argued meets the key structural limitations of the ’482 patent.
- Prior Art Mapping: Petitioner argued that Hillstead discloses a stent built from a single filament into a series of non-helical hoops, with each hoop oriented in a plane perpendicular to the stent axis. For the "means for securing" limitation, Petitioner asserted that Hillstead discloses securing the filament to itself at "junctions" via welding, soldering, or suturing to prevent the stent from unrolling. Petitioner contended that these junctions inherently include securing at the apices and that Hillstead’s incorporation by reference of Palmaz (Patent 4,733,665), which explicitly shows securing apices, confirms this reading. Hillstead's disclosure of multi-segment stents was also mapped to dependent claims 2, 3, 5, and 6.
Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations including Ryan/Porter, Ryan/MacGregor, Hillstead/Palmaz, and Hillstead/Palmaz/Ryan, primarily arguing for the interchangeability of known stent segments, securing means, and bifurcated designs.

"non-helical": Petitioner noted the parties’ agreement in district court litigation to construe this term as "non-spiral." This construction was central to Petitioner's argument that the Patent Owner improperly distinguished prior art during prosecution by arguing that a non-helical design was novel, when prior art like Ryan and Hillstead already disclosed such non-spiral stent structures.
"means for securing an apex...": This is a means-plus-function limitation. Petitioner argued that structures in the prior art, such as Ryan’s "bridge element 13" and Hillstead's "junctions," were structural equivalents that performed the identical function of securing adjacent hoops. Petitioner highlighted that the Patent Owner’s own infringement contentions supported a broad reading of equivalents that would include the integral wire connections found in the prior art.
"segment": Petitioner argued this term should be construed simply as "portion," based on the patent's own specification which uses the terms synonymously (e.g., "proximal stent portion (or segment)").

Interchangeability of Stent Features: A core technical contention underpinning multiple grounds was that by the patent's filing date, both helical and non-helical stent architectures were well-known. Petitioner argued that a POSITA would have understood that features like zig-zag patterns, various securing means (sutures, loops, welds), and bifurcated extensions were common design choices that could be predictably and interchangeably applied to either type of stent architecture.
"Non-Helical" Design Was Not Novel: Petitioner repeatedly asserted that the primary feature argued for patentability during the ’482 patent's prosecution—the "non-helical" hoop configuration—was not novel. It was contended to be a common and well-known design feature in the prior art, as clearly evidenced by references such as Ryan, Hillstead, and Palmaz.

Petitioner requested institution of an inter partes review and cancellation of claims 1-9, 12-13, 21-22, and 30 of Patent 8,192,482 as unpatentable under 35 U.S.C. §102 and §103.