PTAB

IPR2018-01717

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 ’460 patent discloses systems and methods for processing data from electrochemical glucose sensors, particularly continuous glucose monitors. The technology involves applying voltage to a sensor, measuring the signal response, detecting erroneous signals or "artifacts," and using a processor to determine the severity of the error to decide whether to discard the corresponding glucose measurement.

3. Grounds for Unpatentability

Ground 1: Obviousness over Berner - Claims 14-61 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 describes a glucose monitoring device (e.g., GlucoWatch™), discloses every element of the challenged claims. Berner teaches an electrochemical biosensor system with a microprocessor that applies voltages to electrodes (including cycling and switching polarities) to measure a "raw amperometric signal" for glucose concentration. Crucially, Berner explicitly discloses a "data screening step" to detect and eliminate "poor or incorrect signals." This is achieved by identifying deviations from expected signal behavior (e.g., non-monotonic decay) or by measuring and subtracting a "baseline background" current. Petitioner asserted this background current, which is affected by temperature and other factors, constitutes the claimed "erroneous signal." Berner further teaches determining a value associated with the error's severity, such as a "percentage difference between successive background measurements," and discarding the reading if this value exceeds a predetermined threshold (e.g., 15%). Petitioner contended this directly maps to the limitations of independent claim 14.
    • Key Aspects: The argument for other independent claims (20, 26, 32, 38, 44, 50, 56) followed the same logic, asserting that Berner’s disclosure of error sources (like temperature changes, mechanical disturbances, and biochemical interference) inherently teaches that the erroneous signals are associated with the specific conditions recited in those claims, such as temperature, pressure, or available electrode surface area.

Ground 2: Obviousness over Berner in view of Schulman - Claims 62-69 are obvious over Berner and Schulman.

  • Prior Art Relied Upon: Berner (Patent 6,233,471) and Schulman (Patent 5,497,772).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims 62-69, which add specific user interface (UI) limitations not explicitly detailed in Berner. Petitioner argued that while Berner teaches the core glucose sensing and error-rejection system, Schulman discloses the claimed advanced UI functionalities. Schulman describes a continuous glucose monitor with a display that provides multiple viewing modes. It teaches a "graphic display mode" where glucose concentration is plotted as a trend graph over user-selectable time intervals (e.g., 3 to 72 hours). It also teaches a "monitor mode" that displays the current glucose concentration as a large numerical value. Petitioner asserted that these features directly read on the claims requiring a first screen with a trend graph over a first period, a second screen with a trend graph over a different second period, and a third screen with a numerical value. Schulman further discloses toggling between these screens and generating alerts for hypoglycemic conditions.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Schulman's advanced UI with Berner's sensor system to improve its usability, a key factor for continuous monitoring devices. Both patents are directed to electrochemical glucose monitoring systems, making the technologies directly compatible. A POSITA would have viewed the UI as a modular component that could be readily integrated with or substituted into Berner’s system to provide users with more insightful data visualization, such as trend analysis.
    • Expectation of Success: A POSITA would have had a high expectation of success. The combination involved integrating known UI functionalities from Schulman with the known sensor system of Berner. Since the UI and its software are substantially independent of the underlying electrochemical sensing hardware, modifying Berner's display module would have required only well-understood programming changes with no significant technical obstacles.

4. Key Claim Construction Positions

  • Petitioner referenced constructions from a related ITC proceeding, asserting they represent the broadest reasonable interpretation. Key terms included:
    • erroneous signal: "signal that is not indicative of the glucose level." This construction allowed Petitioner to map Berner's disclosure of "poor or incorrect signals" and "baseline background" signals directly onto the claim language.
    • switching, cycling, and pulsing a voltage: "changing a voltage, periodically repeating a voltage, and abruptly changing a voltage for a brief interval." This supported the argument that Berner's description of alternating polarities and switching between iontophoretic and sensing phases met the "apply a voltage" limitation.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 14-69 of the ’460 patent as unpatentable under 35 U.S.C. §103.