PTAB

IPR2018-01715

AgaMatrix, Inc. v. Dexcom, Inc.

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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 relates to signal processing for continuous glucose monitors. The claimed systems use sensor electronics to apply and switch voltages on an electrochemical sensor, measure the resulting signal, evaluate the severity of any signal artifacts, and generate an estimated glucose concentration only if the artifact is below a predetermined threshold.

3. Grounds for Unpatentability

Ground 1: Obviousness over Berner - 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 complete continuous glucose monitoring system known as the "GlucoWatch," teaches every limitation of independent claim 16. Berner allegedly discloses an electrochemical sensor with multiple electrodes and an enzyme-containing hydrogel film; sensor electronics with a microprocessor to control operations; and a process that involves applying a voltage to extract a sample (a first setting) and a different potential to sense glucose (a different setting). Petitioner further contended that Berner’s data screening methods—which check for excessive noise, deviation from expected signal behavior, or high system voltage—constitute the claimed "evaluating a severity associated with a signal artifact" caused by a "non-glucose rate limiting phenomenon." Berner only generates a glucose value if these screens are passed (i.e., severity is below a threshold) and displays the result on an LCD, thus meeting all limitations.
    • Key Aspects: Petitioner emphasized that Berner’s method of correcting for background signals or discarding data based on integrity checks inherently "accounts for the severity associated with the signal artifact" as required by claim 16.

Ground 2: Obviousness over Berner in view of Schulman - 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 independent claim 37 is nearly identical to claim 16 but adds that the measured signal is a "time-varying voltage response" and recites more detailed user interface (UI) functions. Petitioner argued Berner discloses the "time-varying voltage response," as its measured "system voltage" for assessing skin resistance would naturally fluctuate over time. To supply the detailed UI functions, Petitioner turned to Schulman, another prior art continuous glucose monitor. Schulman explicitly teaches a UI that displays glucose data in a graphical mode over user-selectable time intervals of different lengths (e.g., 3 hours vs. 72 hours), a separate numerical display mode, and the ability for a user to toggle between these screens.
    • Motivation to Combine: A POSITA would combine Schulman's advanced UI with Berner's sensor system to improve its capabilities. Petitioner argued Berner itself provides the motivation by recognizing the need to detect and view "trends" in glucose data, a need directly fulfilled by Schulman's graphical display functions. As the UI is a well-understood, modular component, a POSITA would have found it obvious to substitute or integrate Schulman's superior UI into Berner's system.
    • Expectation of Success: Petitioner asserted a high expectation of success. Both references are in the same technical field, their systems are designed for the same purpose, and combining a known UI module with a known sensor system would have been a predictable and straightforward modification for a POSITA.

4. Key Claim Construction Positions

  • signal artifact: Petitioner adopted the construction from a related ITC proceeding, defining this term as "a particular type of noise" or "an artifact relating to signal noise." This construction supports the argument that Berner's data screens for noise and other errors meet this limitation.
  • non-glucose rate limiting phenomenon: Petitioner adopted the construction "a condition, other than glucose, that affects an electrochemical reaction rate of the electrochemical glucose sensor." This is crucial for arguing that phenomena like temperature, high skin resistance, or electrode fouling, all discussed in Berner, meet this claim element.
  • generate an estimated glucose concentration value ... when the severity ... is evaluated to be under a predetermined threshold: Petitioner adopted the construction that this means to "generate an estimated glucose concentration value for display to a user when the severity... is evaluated ... to be less than a predetermined threshold value." This frames the invalidity argument as a simple pass/fail data integrity check, which Petitioner argued is clearly disclosed in Berner's data screening methods.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that review should not be denied under §325(d). Although Berner and Schulman were cited to the USPTO during prosecution of the ’045 patent, they were part of an Information Disclosure Statement listing over 1,200 references. Petitioner contended that this was a "data dump" without any explanation of the references' relevance and that the prosecution history contains no evidence that the examiner ever substantively analyzed these specific, highly material patents. Therefore, the IPR would raise issues not substantively considered during the initial examination.

6. Relief Requested

  • Petitioner requests 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.