PTAB

IPR2018-01715

AgaMatrix Inc v. Dexcom Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Systems and Methods For Replacing Signal Artifacts In A Glucose Sensor Data Stream
  • Brief Description: The ’045 patent discloses systems and methods for processing signals from an electrochemical glucose sensor. The technology involves applying and switching voltages to the sensor, measuring a signal response, and evaluating the severity of signal artifacts to determine whether to accept or discard a glucose measurement.

3. Grounds for Unpatentability

Ground 1: Claims 16-21 and 23-25 are obvious over Berner.

  • Prior Art Relied Upon: Berner (Patent 6,233,471).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Berner, which discloses a continuous glucose monitoring system (e.g., a GlucoWatch™), teaches all limitations of independent claim 16. Berner’s biosensor was described as an electrochemical sensor with multiple electrodes and an enzyme-containing hydrogel pad for measuring glucose. It uses a microprocessor to perform a two-phase process: a reverse-iontophoretic phase to extract a sample (first voltage setting) and a sensing phase to measure glucose (second voltage setting), thereby teaching the application and switching of voltage. Berner measures electrical signals (e.g., current, "system voltage") responsive to these phases. Crucially, Berner disclosed multiple data screening methods to invalidate or correct poor signals, which Petitioner mapped to the claimed "evaluate a severity associated with a signal artifact." These screens check for conditions like high skin resistance or signal instability—which Petitioner asserted are "non-glucose rate limiting phenomenon"—and discard the measurement if a threshold is exceeded. If the signal is deemed valid (severity is below the threshold), Berner generates a glucose concentration value and displays it on an LCD, satisfying the remaining claim limitations.
    • Key Aspects: Petitioner contended that Berner’s detailed data screening protocols, such as comparing a "system voltage" against a high voltage threshold or assessing "voltage stability," directly correspond to the claimed evaluation of artifacts associated with non-glucose phenomena.

Ground 2: Claims 37-39 and 41-43 are obvious over Berner in view of Schulman.

  • Prior Art Relied Upon: Berner (Patent 6,233,471) and Schulman (Patent 5,497,772).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Berner teaches most limitations of independent claim 37, which is similar to claim 16 but adds that the measured signal is a "time-varying voltage response" and recites more detailed user interface functions. Petitioner argued Berner discloses measuring voltages (e.g., "system voltage") that are inherently time-varying due to fluctuating physiological conditions like skin resistance. While Berner taught a basic user interface with alerts and readouts, Petitioner alleged that Schulman, also in the field of continuous glucose monitoring, supplied the specific missing user interface functions. Schulman was shown to disclose a display with multiple screens, including a "graphic display mode" plotting glucose data over user-selectable time periods (e.g., 3 hours vs. 72 hours) and a "monitor mode" showing the current value in large numerals. Schulman also disclosed toggling between these screens and generating alerts for high or low glucose levels.
    • Motivation to Combine: A POSITA would combine Schulman's advanced user interface with Berner's sensor to improve its functionality. Petitioner argued that Berner itself provides the motivation by recognizing the need for a user to detect "blood glucose swings or trends." Schulman’s graphical display of glucose data over various time periods directly addresses this stated need. As both patents are in the same field and address the same problem, and because user interfaces are largely modular, it would have been a predictable and desirable improvement.
    • Expectation of Success: Petitioner argued a POSITA would have had a reasonable expectation of success. The combination would have involved reprogramming Berner's existing microprocessor to incorporate Schulman's known display functionalities. This was presented as a straightforward modification with no significant technical obstacles, as the user interface is substantially independent of the core sensing components.

4. Key Claim Construction Positions

  • Petitioner relied on claim constructions from a related ITC proceeding for several key terms, arguing they represented the broadest reasonable interpretation.
  • "evaluate a severity associated with a signal artifact": This was interpreted functionally as comparing a signal against a predetermined threshold to determine its validity. This construction was central to mapping Berner's data screening methods (e.g., comparing system voltage to a threshold) to the claims.
  • "non-glucose rate limiting phenomenon": Construed as "a condition, other than glucose, that affects an electrochemical reaction rate of the electrochemical glucose sensor." Petitioner used this construction to argue that factors like high skin resistance, temperature fluctuations, or mechanical disturbances, all discussed in Berner as sources of error, met this limitation.
  • "enzyme-containing film": Construed as "a thin layer that includes an enzyme." Petitioner argued Berner's enzyme-containing hydrogel, described as a disk or pad within a layered assembly, met this definition.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 16-21, 23-25, 37-39, and 41-43 of the ’045 patent as unpatentable under 35 U.S.C. §103.