PTAB

IPR2018-01718

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 relates to glucose sensor systems that apply a voltage to an electrochemical sensor, measure the resulting signal response, and evaluate the severity of any detected signal error to determine whether to accept or discard the corresponding glucose measurement.

3. Grounds for Unpatentability

Ground 1: Obviousness over White and Beaty - Claims 14-18, 20-24, 26-30, 32-36, 38-42, and 50-54 are obvious over White in view of Beaty.

  • Prior Art Relied Upon: White (Patent 5,243,516) and Beaty (WO 99/32881).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that White disclosed the foundational elements of the claimed system, including an electrochemical glucose sensor with electrodes, an enzyme-containing film, and a microprocessor that applies voltage and measures current. White’s system performs error detection by determining if the measured current deviates from a predetermined Cottrell current relationship. Petitioner asserted that Beaty taught applying AC voltage signals to a biosensor to detect and compensate for various errors not addressed by White, such as those arising from inadequate sample volume, temperature variations, and the presence of biochemical interferents (e.g., hematocrit). Beaty’s methods were described as applicable to improve the accuracy of the type of biosensor disclosed in White.
    • Motivation to Combine: Petitioner contended that Beaty provided express motivation to combine its teachings with White. Beaty explicitly states that its techniques for improving measurement accuracy can be applied to instruments of the type described in White’s ’516 patent. A POSITA would therefore combine Beaty’s known error-correction methods with White’s known sensor to achieve the predictable result of a more robust and accurate glucose measurement system.
    • Expectation of Success: Petitioner argued a POSITA would have a high expectation of success in combining the references. The combination involved applying known techniques to a known device within the same field of technology. The necessary modifications would primarily involve software changes and the use of common circuitry, without requiring fundamental alterations to White's electrochemical cell.

Ground 2: Obviousness over White, Beaty, and Schulman - Claims 62-66 and 68 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 upon the combination of White and Beaty for the core error-detection system and introduces Schulman to teach the specific user interface (UI) limitations added in claims 62-66 and 68. Petitioner argued that Schulman disclosed a continuous glucose monitoring system with an advanced UI featuring multiple display screens. Schulman’s UI could present trend graphs over user-selectable time periods (e.g., 3 to 72 hours), display the current glucose value as a large numerical output, allow a user to toggle between these different display modes, and generate alarms for hyperglycemic or hypoglycemic conditions. These features allegedly mapped directly onto the UI limitations of the challenged claims.
    • Motivation to Combine: Petitioner argued a POSITA would combine Schulman’s teachings to improve the usability and functionality of the sensor system disclosed by White and Beaty. The petition asserted that a display unit is a modular component, and it would have been a simple and logical step to replace or enhance the basic display of the White/Beaty system with the more sophisticated graphical and alarm features taught by Schulman to provide more valuable data visualization and safety alerts to the user.
    • Expectation of Success: A POSITA would have expected success because the UI functions are substantially independent of the core electrochemical sensor and signal analysis. This modularity would allow for straightforward integration of Schulman's display features through well-understood software reprogramming and hardware substitution.

4. Key Claim Construction Positions

  • Petitioner referenced claim constructions from a related International Trade Commission (ITC) proceeding, arguing that the broadest reasonable interpretation for the IPR would be at least as broad as those definitions. Key proposed constructions included:
    • "switching, cycling, and pulsing a voltage": Construed by the ITC judge as "changing a voltage, periodically repeating a voltage, and abruptly changing a voltage for a brief interval."
    • "erroneous signal": Construed by the ITC judge as a "signal that is not indicative of the glucose level."
  • Petitioner argued these constructions were important for mapping the error-detection methodologies of the prior art, which involved changing applied voltages and analyzing the response for signals that were not indicative of the true glucose level.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 14-18, 20-24, 26-30, 32-36, 38-42, 50-54, 62-66, and 68 of the ’460 patent as unpatentable under 35 U.S.C. §103.