LifeScan Global Corp v. PHC Holdings Corp

1. Case Identification

• Case #: IPR2019-01127
• Patent #: 8,480,878
• Filed: May 24, 2019
• Petitioner(s): LifeScan, Inc.
• Patent Owner(s): PHC Holdings Corporation
• Challenged Claims: 1-8 and 12-18

2. Patent Overview

• Title: Biosensor, Thin Film Electrode Forming Method, Quantification Apparatus, and Quantification Method
• Brief Description: The ’878 patent discloses electrochemical biosensors for quantifying a substrate (e.g., glucose) in a sample liquid. The sensor generally comprises opposing insulating supports, electrodes made from noble metals, a reagent layer, and a spacer defining a sample supply path.

3. Grounds for Unpatentability

Ground 1: Anticipation over Heller - Claims 1-3, 8, 12-15, 17, and 18 are anticipated by Heller

• Prior Art Relied Upon: Heller (WO 1998/035225).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Heller, which discloses a "Small Volume In Vitro Analyte Sensor," taught every element of the challenged claims. Independent claim 1’s limitations were allegedly met by Heller's disclosure of a sensor with an insulating support (Mylar film), a working electrode made of a noble metal (e.g., gold, platinum, palladium) on the support, and a counter electrode on a separate cover. Petitioner asserted that Heller’s "sensing layer" was the claimed "reagent layer," and its "spacer" (element 28) was provided on and covered part of the reagent layer. Crucially, Petitioner contended that Heller’s spacer defines a sample chamber that is necessarily narrower than the partially covered reagent layer, thus anticipating the "narrower than the reagent layer" limitation. For dependent claims, Petitioner argued Heller disclosed the spacer forming a "vertical wall" (claim 2), the use of palladium and gold (claims 3 and 18), electrode separation between 0.005 mm and 0.3 mm (claim 8), and a reagent layer with an enzyme, electron transfer agent, and hydrophilic polymer (claims 12-13).

Ground 2: Anticipation over Ohara - Claims 1-3, 8, 12, 14, 15, 17, and 18 are anticipated by Ohara

• Prior Art Relied Upon: Ohara (Patent 6,193,873).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Ohara, which describes an electrochemical device for measuring analytes, anticipated the claims. Ohara’s device allegedly included an insulating support (polyester base 14), a working electrode formed from a noble metal (palladium coating 16), and a "dry reagent" layer deposited on the electrode. Petitioner mapped Ohara’s "spacing layer 20," a double-sided adhesive with a cutout (22), to the claimed spacer layer, arguing it covers part of the reagent layer and its cutout defines a supply path narrower than the reagent layer itself. Ohara’s "top layer 24" with a gold coating (28) was identified as the claimed cover with a counter electrode. Petitioner further argued that because Ohara's device requires the sample to fill the gap between the electrodes to function, portions of the working electrode, counter electrode, and reagent layer are necessarily within the supply path, as claimed. Dependent claims were allegedly met by Ohara’s disclosure of palladium and gold electrodes (claims 3 and 18), a spacer thickness under 200 µm (meeting claim 8), and an air hole at the end of the supply path cutout (claim 14).

Ground 3: Obviousness over Heller, Ito, and Applicant-Admitted Prior Art - Claim 16 is obvious over Heller in view of Ito and Applicant-admitted prior art

• Prior Art Relied Upon: Heller (WO 1998/035225), Ito (Patent 5,384,028), and Applicant-admitted prior art from the ’878 patent specification.

• Core Argument for this Ground:

  • Prior Art Mapping: This ground targeted claim 16, which adds a "correcting unit that stores correction data generated for each production lot" to the biosensor of claim 1. Petitioner first established that Heller taught the base biosensor of claim 1. The Petitioner then pointed to the ’878 patent’s own specification, which acknowledged that using external correction chips was a known and "considerably troublesome" problem in the prior art. Ito was presented as a solution, disclosing a biosensor with an integrated memory for storing fabrication data, lot number, and biosensor characteristics, which could be read by a measurement unit.
  • Motivation to Combine: A POSITA would combine Ito's integrated memory with Heller's sensor to solve the well-documented problem of using separate, error-prone external correction chips. The motivation was to improve usability and reduce measurement errors, a recognized goal in the field.
  • Expectation of Success: Petitioner argued there was a high expectation of success, as combining a known memory component with a known sensor to automate a manual correction step was a straightforward application of existing technologies to solve a known problem.

• Additional Grounds: Petitioner asserted numerous additional challenges, including: anticipation of claims 1-3, 8, and 12-15 by Liamos (Patent 6,616,819); obviousness of claims 4-6 over Heller, Ohara, or Liamos in view of Bhullar (Patent 6,662,439) or Hodges (Patent 5,942,102) to add specific electrode thickness ranges; and a comprehensive obviousness challenge to all claims over Blatt (European Application No. 88105365.6) in view of the other primary references.

4. Key Claim Construction Positions

• "vertical" (claim 2): Petitioner proposed this term be construed to mean "perpendicular to the plane of the support 1 and cover 13," based on the orientation shown in Figure 1(c) of the ’878 patent. This construction was used to argue that the side walls of the spacers in Heller and Ohara meet the limitation.
• "wettability index" (claim 7): Petitioner proposed construing this term to mean "any parameter that indicates the degree to which a substance can be wet by a liquid." Petitioner argued that this term is numerically equivalent to surface free energy, allowing them to rely on prior art articles (Todd and Vitos) showing palladium has an inherent surface free energy far exceeding the claimed threshold.

5. Relief Requested

• Petitioner requests institution of IPR and cancellation of claims 1-8 and 12-18 of the ’878 patent as unpatentable.