DCT
3:18-cv-00134
Arbmetrics LLC v. Dexcom Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Arbmetrics, LLC (Ohio)
- Defendant: Dexcom Inc. (Delaware)
- Plaintiff’s Counsel: Fernald Law Group; Nelson Bumgardner PC
- Case Identification: 3:18-cv-00134, S.D. Cal., 01/19/2018
- Venue Allegations: Plaintiff alleges venue is proper in the Southern District of California because Defendant's principal place of business is located in the district, and it has allegedly committed acts of infringement and conducted substantial business there.
- Core Dispute: Plaintiff alleges that Defendant’s continuous glucose monitoring (CGM) systems infringe a patent related to implantable electrochemical biosensors.
- Technical Context: The technology concerns methods for improving the accuracy of implantable biosensors, which are critical for real-time monitoring of biological analytes like glucose for diabetes management.
- Key Procedural History: The complaint alleges that Defendant has been aware of the patent-in-suit for many years, citing its disclosure in over 350 of Defendant's own U.S. patent applications, with the first such disclosure allegedly occurring in 2004. This history is presented to support the claim of willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 1999-09-14 | ’225 Patent Priority Date |
| 2002-01-29 | ’225 Patent Issue Date |
| 2004-11-30 | Alleged first disclosure of ’225 patent by Dexcom to the USPTO |
| 2009-07-24 | Alleged citation of ’225 patent by USPTO examiner against a Dexcom patent application |
| 2018-01-19 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,343,225 - "Implantable Glucose Sensor," issued Jan. 29, 2002
The Invention Explained
- Problem Addressed: The patent describes a significant challenge for enzyme-based implantable sensors: "oxygen limitation" (U.S. Patent No. 6,343,225, col. 4:9-14). In human tissue, the concentration of glucose can be far greater than that of available oxygen. This disparity can cause the sensor's signal to become dependent on the limited oxygen supply rather than the actual glucose level, leading to inaccurate readings ( ’225 Patent, col. 4:9-22).
- The Patented Solution: The invention proposes creating an "oxygen-reservoir" in direct contact with the sensor's enzyme layer (’225 Patent, Abstract). This is achieved by creating a "stabilized enzyme emulsion" containing an oxidase enzyme, an aqueous solution, and a "water immiscible oxygen dissolving substance," such as a perfluorocarbon liquid. The mixture is stabilized by a cross-linking agent to form a gel, which physically traps "particles" of the oxygen-dissolving substance next to the enzyme, thereby buffering against low or fluctuating oxygen levels in the surrounding tissue (’225 Patent, col. 8:25-35).
- Technical Importance: This approach sought to improve the accuracy and in-vivo stability of implantable sensors, a critical step toward reliable long-term continuous glucose monitoring and the development of automated insulin delivery systems (’225 Patent, col. 2:1-17).
Key Claims at a Glance
- The complaint asserts independent claim 1 and dependent claims 2, 5, 7, and 8 (Compl. ¶18).
- Independent Claim 1 requires:
- a conductive electrode;
- a stabilized enzyme emulsion in contact with the electrode, where the emulsion comprises:
- an oxidase enzyme for oxidizing an organic substrate;
- a water immiscible oxygen dissolving substance, emulsified into intimate contact with the enzyme; and
- a protein crosslinking agent that forms a stabilized gel containing crosslinked protein and "particles of said oxygen dissolving substance."
- The complaint does not explicitly reserve the right to assert other claims, but standard practice allows for amending such contentions.
III. The Accused Instrumentality
Product Identification
- The Dexcom Seven® Plus CGM Sensor, Dexcom G4® PLATINUM CGM Sensor, and Dexcom G5® Mobile CGM Sensor (the "Accused Products") (Compl. ¶21).
Functionality and Market Context
- The Accused Products are identified as implantable sensors used for continuous glucose monitoring in individuals with diabetes (Compl. ¶¶12, 19). The complaint alleges, on information and belief, that these sensors are constructed with a conductive electrode and a "stabilized enzyme emulsion" (Compl. ¶19). This emulsion is alleged to contain glucose oxidase, a "water immiscible oxygen dissolving substance" (such as perfluorocarbons or silicone oils), and a "protein crosslinking agent" (such as aldehydes) (Compl. ¶¶19, 21-23).
- The complaint cites Defendant’s SEC filings to establish that Dexcom is a medical device company specializing in the commercialization of CGM systems, positioning the Accused Products as central to its business (Compl. ¶11).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
’225 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a conductive electrode | The Accused Products are alleged to be implantable sensors that comprise a conductive electrode. | ¶19 | col. 29:19 |
| a stabilized enzyme emulsion in contact with the electrode, the enzyme emulsion comprising: an oxidase enzyme that quantitatively oxidizes the organic substrate | The Accused Products allegedly comprise a stabilized enzyme emulsion containing an oxidase enzyme (specifically, glucose oxidase) that oxidizes the organic substrate (glucose). | ¶19, ¶23 | col. 29:20-24 |
| a water immiscible oxygen dissolving substance emulsified into intimate contact with the enzyme to provide oxygen | The complaint alleges, on information and belief, that the enzyme emulsion in the Accused Products contains a water immiscible oxygen dissolving substance (from a group including perfluorocarbons and silicone oils) that is emulsified to provide oxygen to the enzyme. | ¶19, ¶21 | col. 29:25-28 |
| a protein crosslinking agent to crosslink and insolubilize the enzyme forming a stabilized gel comprising crosslinked protein and particles of said oxygen dissolving substance | The complaint alleges, on information and belief, that the enzyme emulsion in the Accused Products includes a protein crosslinking agent that forms a stabilized gel. This gel allegedly comprises crosslinked protein and particles of the oxygen dissolving substance. | ¶19, ¶22 | col. 29:29-33 |
- Identified Points of Contention:
- Technical Questions: A primary factual dispute will concern the specific chemical composition and physical micro-structure of the sensor layer in the Accused Products. The infringement allegations regarding the emulsion's components are made "on information and belief." A key question for discovery will be whether the Accused Products actually contain a "water immiscible oxygen dissolving substance" and, if so, whether it exists as discrete "particles" enmeshed within a "crosslinked protein gel" as required by the claim language.
- Scope Questions: The case may turn on the interpretation of the claim’s structural requirements. For example, does the phrase "stabilized gel comprising crosslinked protein and particles of said oxygen dissolving substance" require a specific physical arrangement where discrete droplets of the oxygen-carrying substance are suspended in a protein matrix, or could it more broadly read on other chemical formulations that achieve a similar result?
V. Key Claim Terms for Construction
The Term: "stabilized enzyme emulsion"
- Context and Importance: This term appears in the claim preamble and describes the core of the patented technology. The definition will be critical for determining whether the chemical formulation used in Dexcom’s sensors falls within the scope of the claims.
- Intrinsic Evidence for a Broader Interpretation: The specification introduces the invention broadly as being "directed towards a fluorocarbon-containing enzyme suspension or emulsion," which could suggest the term covers a range of mixtures (’225 Patent, col. 5:23-25).
- Intrinsic Evidence for a Narrower Interpretation: The detailed description explains that "Tiny perfluorocarbon droplets are then enmeshed permanently by a cross-linked protein gel," suggesting a specific physical structure where one phase (the oxygen carrier) is dispersed within another (the protein gel) (’225 Patent, col. 8:32-35).
The Term: "particles of said oxygen dissolving substance"
- Context and Importance: This term in the body of the claim defines the physical form of the oxygen-reservoir component. Infringement will depend on whether the Accused Products contain the oxygen-dissolving substance as "particles." Practitioners may focus on this term because it implies a specific structural limitation, not merely a chemical mixture.
- Intrinsic Evidence for a Broader Interpretation: The term "particles" is not explicitly defined and could be argued to cover any discrete domains or regions of the substance within the gel matrix.
- Intrinsic Evidence for a Narrower Interpretation: The patent’s method of preparation, which involves sonicating a liquid perfluorocarbon to create an emulsion before adding a cross-linking agent, supports a narrower reading where "particles" refers to distinct droplets of the immiscible liquid suspended in the resulting gel (’225 Patent, col. 9:41-48).
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement, stating that Defendant provides user guides, online manuals, and instructional videos that "instruct and encourage" end-users to operate the Accused Products in a manner that directly infringes the patent (Compl. ¶¶27-28).
- Willful Infringement: The willfulness claim is based on alleged pre-suit knowledge of the ’225 patent. The complaint alleges that Defendant has been aware of the patent since at least November 2004, citing its repeated disclosure by Dexcom on Information Disclosure Statements (IDS) filed with the USPTO during the prosecution of its own patent portfolio. The complaint further alleges the ’225 patent is cited on at least 240 of Dexcom's issued patents and was referenced by a USPTO examiner against a Dexcom application (Compl. ¶¶32-36).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of structural and compositional equivalence: Does the material composition of the accused Dexcom sensors, once revealed in discovery, meet the specific structural limitations of Claim 1? The analysis will focus on whether it contains a "stabilized gel" with enmeshed "particles" of an oxygen-dissolving substance, or if it utilizes a fundamentally different technical approach.
- The case will also turn on a question of claim construction: Will the court interpret the term "stabilized enzyme emulsion" and its components based on the specific physical structures described in the patent's embodiments, or will it adopt a broader functional definition? The answer will define the boundaries of the patented invention.
- Finally, a key question for willfulness will be the character of Defendant's conduct: Given the complaint's detailed allegations of Defendant's long-standing awareness of the ’225 patent, the court will have to examine whether Defendant proceeded with a good-faith belief of non-infringement or invalidity, or if its actions constituted objective recklessness.