PTAB

IPR2019-00882

Abbott Vascular Inc v. FlexSTent LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Vascular Stent
  • Brief Description: The ’035 patent is directed to a vascular stent designed for superior flexibility, comprising circumferential "vertical branches" and longitudinal "horizontal branches." The horizontal branches feature waveform projections and are thinner than the vertical branches.

3. Grounds for Unpatentability

Ground 1: Obviousness over Richter-Handbook and Richter-404 - Claims 1-3 are obvious over Richter-Handbook in view of Richter-404.

  • Prior Art Relied Upon: Richter-Handbook (MARTIN DUNITZ, HANDBOOK OF CORONARY STENTS, 1st Ed., 1997) and Richter-404 (Patent 5,807,404).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the Richter-Handbook, which describes the commercially available NIR stent, discloses a stent structure with all the features of claim 1, including vertical branches, and horizontal branches with waveform projections. The Handbook was asserted to disclose dimensions that fall within the claimed ranges for vertical branch width and thickness (claim 1), branch unit lengths (claim 2), and overall stent diameter and length (claim 3). The only element not directly met was the horizontal branch width, which the Handbook disclosed as 0.10 mm, slightly outside the claimed 0.05-0.08 mm range. Richter-404, by the same inventor, was argued to cure this deficiency by expressly teaching the modification of the same NIR stent to narrow its horizontal branches by 40-50%, resulting in a width of 0.05-0.06 mm, squarely within the claimed range.
    • Motivation to Combine: A POSITA would combine these references because they were authored by the same inventor, describe the same NIR stent, and address the same technical problem. Richter-404 explicitly taught narrowing the horizontal branches of the NIR stent to achieve "greater flexibility," a well-known goal in stent design. This provided an express and direct motivation to apply the teachings of Richter-404 to the stent described in the Richter-Handbook.
    • Expectation of Success: A POSITA would have a high expectation of success because the modification taught in Richter-404 was described for the specific stent disclosed in the Richter-Handbook, addressing a known problem with a predictable solution.

Ground 2: Obviousness over Fischell, Alone or in View of Penn - Claims 1-3 are obvious over Fischell, alone or in view of Penn.

  • Prior Art Relied Upon: Fischell (European Patent No. 0669114) and Penn (WO 97/32543).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Fischell discloses an expandable stent for coronary arteries with "circular rings" (vertical branches) connected by "undulating longitudinals" (horizontal branches with waveform projections). Fischell disclosed broad dimensional ranges for branch thickness, width, unit lengths, and overall stent dimensions that overlap with the ranges recited in claims 1-3. Petitioner argued that a POSITA designing a stent for coronary applications, as taught by Fischell, would have focused on the lower end of Fischell's disclosed ranges, resulting in dimensions that are nearly identical to those claimed.
    • Motivation to Combine (for §103 grounds): The combination with Penn was presented as an alternative argument, particularly if the claims were construed to require straight portions in the horizontal branches. Penn taught various waveform shapes for horizontal branches, including combinations of waveform and straight sections, to improve lateral flexibility and reduce foreshortening. A POSITA would combine Fischell's design with Penn's teachings to optimize flexibility and crimping performance, both known objectives in stent design.
    • Expectation of Success: A POSITA would expect success in optimizing Fischell's disclosed dimensions for a coronary stent, as this was a matter of routine experimentation. The variables of branch width and thickness were known result-effective variables for controlling stent properties like flexibility and radial strength.

4. Key Claim Construction Positions

  • "vertical branches" and "horizontal branches having wave form projections": Petitioner argued that these terms should be construed based on their general orientation within the stent, not their specific shape. "Vertical branches" refer to the generally circumferential ring-like elements, while "horizontal branches" refer to the generally longitudinal connectors. This construction means that the branches do not need to be perfectly straight or circular, and the "waveform projections" encompass any non-linear shape that confers flexibility, which allows the prior art to meet these limitations.

5. Key Technical Contentions (Beyond Claim Construction)

  • Priority Date Challenge: Petitioner contended that the ’035 patent is not entitled to its claimed 1997 priority date from a Korean application. It was argued the Korean application failed the written description requirement of 35 U.S.C. §112 because it did not disclose the claimed dimensional ranges for branch width and thickness. This contention, if successful, establishes a later effective filing date of July 16, 1998, making references like the Richter-Handbook and Penn valid prior art.

6. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion to deny institution under §325(d). The primary references (Richter-Handbook, Richter-404, Fischell, Penn) were not considered by the examiner during prosecution. Petitioner asserted the examiner erred by allowing the claims based on a procedurally and substantively defective inventor declaration regarding unexpected results. The new art and arguments were presented as being materially different from the prosecution record and establishing a compelling case of unpatentability.

7. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-3 of the ’035 patent as unpatentable.