PTAB

IPR2018-01716

AgaMatrix Inc v. Dexcom Inc

Log In
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 glucose sensor systems that employ sensor electronics to apply different voltages to an electrochemical sensor, measure the signal response, and evaluate the severity of signal artifacts to decide whether to accept or discard a glucose measurement.

3. Grounds for Unpatentability

Ground 1: Claims 16-20 and 23-25 are obvious over White in view of Beaty.

  • Prior Art Relied Upon: White (Patent 5,243,516) and Beaty (International Publication No. WO 99/32881).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that White, the primary reference, discloses the fundamental elements of independent claim 16. This includes an electrochemical glucose sensor with electrodes and an enzyme film, along with sensor electronics (a microprocessor with memory) to perform measurements. White’s system evaluates signal artifacts by determining whether a measured current deviates from a predetermined Cottrell current relationship; if the deviation (severity) is below a threshold, a glucose value is generated and displayed. Petitioner asserted that Beaty remedies deficiencies in White by teaching an interference-correction technique. This technique involves applying different AC voltage signals at specified frequencies as a preliminary step to the main glucose measurement. The combination of White's core system and Beaty's interference-correction method allegedly discloses applying a voltage at a first setting (per Beaty), switching the voltage to a different setting (e.g., from Beaty’s AC signal to White’s DC measurement voltage), and measuring the signal response.
    • Motivation to Combine: A POSITA would combine White and Beaty because they are in the same field of amperometric glucose measurement, and Beaty explicitly cites White twelve times, positioning its own teachings as an improvement for "improving the accuracy of measurements made with instruments of the type described in" White. Beaty’s interference-correction function was presented as a modular component that directly addresses White’s stated goal of preventing erroneous readings, providing a clear reason to integrate the two.
    • Expectation of Success: Petitioner contended that a POSITA would have a reasonable expectation of success in combining the references. The modification would involve reprogramming White’s microprocessor to incorporate Beaty’s pre-measurement voltage application steps, a task well within the skill of a POSITA at the time.

Ground 2: Claims 37-38 and 41-43 are obvious over White and Beaty in view of Schulman.

  • Prior Art Relied Upon: White (Patent 5,243,516), Beaty (WO 99/32881), and Schulman (Patent 5,497,772).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds on the combination of White and Beaty from Ground 1 to meet the base limitations of independent claim 37, which are nearly identical to claim 16. The challenge focuses on the additional, specific user interface (UI) limitations recited in claim 37, which Petitioner argued are disclosed by Schulman. These limitations include displaying glucose data on multiple screens covering different time periods (e.g., 3 hours vs. 72 hours), allowing a user to toggle between these screens, and generating alerts for hyperglycemic or hypoglycemic conditions. Petitioner asserted that Schulman, which discloses a continuous glucose monitoring system, explicitly teaches a UI with a "graphic display mode" showing plots over user-selected time intervals (3 to 72 hours), a "monitor mode" showing the current value, and menu buttons for toggling between them. Schulman further discloses generating an alarm signal if a measurement falls outside preset limits.
    • Motivation to Combine: A POSITA would combine Schulman's UI features with the White/Beaty sensor system to enhance its functionality and usability. All three references are in the glucose monitoring field. White discloses a basic need to "enable[] the user to see the results," and Schulman provides a sophisticated, known solution for visualizing data trends and providing critical alerts, which directly addresses White's general objective. The substantial overlap in function and field would have provided a strong incentive for integration.
    • Expectation of Success: Petitioner argued that incorporating Schulman’s UI would be a straightforward modification. Since UI functions are substantially independent of the underlying glucose sensing hardware, a POSITA would have viewed Schulman's UI as a modular component that could be readily adapted to the White/Beaty system with a high expectation of success.

4. Key Claim Construction Positions

  • Petitioner argued that the claim terms should be given their plain meanings under the broadest reasonable interpretation standard. It noted that several key terms were construed in a related ITC proceeding and that these constructions were at least as broad as the correct interpretation.
  • The term “switch the voltage applied...to a different setting” was construed as “change the voltage that was put to use...to a different specified condition.” This construction was central to Petitioner’s argument that transitioning from Beaty’s AC interference-check voltage to White’s DC measurement voltage meets this limitation.
  • The phrase “evaluate a severity associated with a signal artifact” was mapped to White’s process of comparing measured current ratios against a prestored constant to check for deviation from the expected Cottrell curve.
  • The limitation “wherein the estimated glucose concentration value accounts for the severity associated with the signal artifact” was construed to be met by White’s data-screening process, where a glucose value is only generated if the severity of the artifact (deviation) is below a predetermined threshold.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 16-20, 23-25, 37-38, and 41-43 of the ’045 patent as unpatentable under 35 U.S.C. §103.