DCT
3:16-cv-00536
Waveform Tech Inc v. Dexcom Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: AgaMatrix, Inc. (Delaware)
- Defendant: Dexcom, Inc. (Delaware)
- Plaintiff’s Counsel: Schwabe, Williamson & Wyatt, P.C.
- Case Identification: 3:16-cv-00536, D. Or., 03/28/2016
- Venue Allegations: Venue is asserted in the District of Oregon based on allegations that Defendant transacts business and has committed acts of infringement in the district. The complaint further notes that the patents' inventors reside in Oregon, the technology was conceived and reduced to practice in Oregon, and Plaintiff maintains its exclusive facility for producing the patented sensors in the district.
- Core Dispute: Plaintiff alleges that Defendant’s continuous glucose monitoring (CGM) systems infringe three patents related to the construction of durable, flexible indwelling sensors.
- Technical Context: The technology concerns indwelling electrochemical sensors for real-time glucose monitoring in individuals with diabetes, a significant and established medical device market.
- Key Procedural History: The complaint was filed on March 28, 2016. Subsequently, Dexcom filed petitions for inter partes review (IPR) against all three patents-in-suit. The U.S. Patent and Trademark Office instituted reviews and ultimately issued certificates cancelling several asserted claims, including the primary independent claims of the ’202 and ’574 patents. These post-filing developments substantially alter the legal landscape of the dispute as originally pleaded.
Case Timeline
| Date | Event |
|---|---|
| 2003-06-16 | Priority date for ’202 and ’433 Patents |
| 2003-08-14 | Priority date for ’574 Patent |
| 2006-12-05 | U.S. Patent No. 7,146,202 issues |
| 2009-05-05 | U.S. Patent No. 7,529,574 issues |
| 2012-05-29 | U.S. Patent No. 8,187,433 issues |
| 2016-03-28 | Complaint filed |
| 2016-08-25 | IPR filed against ’202 Patent (IPR2016-01679) |
| 2016-08-25 | IPR filed against ’433 Patent (IPR2016-01680) |
| 2017-03-08 | IPR filed against ’574 Patent (IPR2017-01051) |
| 2019-10-22 | IPR Certificate issues for ’574 Patent |
| 2019-12-09 | IPR Certificate issues for ’433 Patent |
| 2020-01-08 | IPR Certificate issues for ’202 Patent |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,146,202 - "Compound Material Analyte Sensor"
The Invention Explained
- Problem Addressed: The patent describes a problem with prior art indwelling wire sensors used for glucose monitoring. These sensors were often made of platinum, which is described as a "weak metal that is easily broken with only a little flexure" from bodily movement, posing a danger to the patient and limiting the sensor's useful life (Compl. ¶¶16-17; ’202 Patent, col. 1:10-24). Platinum is also noted as being expensive (Compl. ¶17; ’202 Patent, col. 1:28-30).
- The Patented Solution: The invention is a method using a sensor constructed with a composite wire. This wire has a "structurally robust material" core, such as tantalum, which provides strength and flexibility, and an outer plated layer of an "electrochemically active metal," such as platinum, to perform the sensing function (Compl. ¶18; ’202 Patent, Abstract). This design, illustrated in the complaint's reproduction of Figure 1, aims to provide durability without sacrificing electrochemical performance or incurring the high cost of a solid platinum wire (’202 Patent, col. 2:10-23). The complaint references Figure 1 from the patent, which shows a cross-section of a sensor tip with a core (24) and an electrochemically active layer (26) (Compl. ¶19).
- Technical Importance: This composite structure sought to create more reliable, safer, and affordable indwelling sensors suitable for continuous, multi-day wear, a key objective for advancing CGM technology (’202 Patent, col. 2:39-42).
Key Claims at a Glance
- The complaint asserts independent claim 1 and several dependent claims (Compl. ¶41).
- Essential elements of independent claim 1 include:
- providing a sensor having (i) a structurally flexible core with an outer surface, and (ii) a layer of electrochemically active metal surrounding, covering, and in contact with the core's outer surface;
- placing at least a portion of the sensor into an animal body; and
- measuring an electric current produced by the sensor to determine analyte concentration.
- Note: The provided Inter Partes Review Certificate (US 7,146,202 K1) indicates that claim 1 was cancelled in a post-filing proceeding.
U.S. Patent No. 8,187,433 - "Compound Material Analyte Sensor"
The Invention Explained
- Problem Addressed: Stemming from the same provisional application as the ’202 patent, this patent addresses the same durability and cost issues with prior art sensors (Compl. ¶14; ’433 Patent, col. 1:12-32).
- The Patented Solution: The ’433 patent claims the sensor apparatus itself, rather than the method of use. The invention is an analyte sensing element comprising a structurally flexible core, a "continuous layer of electrochemically active metal" that covers the core and "prevents body fluid from contacting" it, and a membrane system with an enzyme at least partially surrounding the active metal layer (’433 Patent, claim 1). The specification, which the complaint notes is "substantially identical" to that of the '202 patent, explains this structure provides the requisite strength and sensing capability (Compl. ¶14; ’433 Patent, col. 3:41-50).
- Technical Importance: By claiming the physical device, the patent sought to protect the specific composite structure intended to improve the viability of long-term indwelling CGM sensors.
Key Claims at a Glance
- The complaint asserts independent claim 1 and several dependent claims (Compl. ¶50).
- Essential elements of independent claim 1 include:
- a structurally flexible core having an outer surface;
- a continuous layer of electrochemically active metal surrounding, covering, and in contact with the core's outer surface;
- wherein the metal layer prevents body fluid from contacting the core and has at least one sensing surface; and
- wherein the metal layer is at least partially surrounded by a membrane system comprising an enzyme.
- The complaint reserves the right to assert dependent claims (Compl. ¶25).
U.S. Patent No. 7,529,574 - "Method of Constructing a Biosensor"
Technology Synopsis
This patent addresses a manufacturing challenge in creating biosensors: applying a sufficiently thick layer of viscous, curable liquids (e.g., enzyme membranes) onto the sensor's active surface (’574 Patent, col. 1:7-15). The patented solution is a sensor design featuring "at least two nubs of dielectric material" that extend outward from the sensor's electrochemically active surface, forming a cavity between them that provides structural support to hold the membrane system in place during and after application (’574 Patent, claim 1). The complaint includes Figure 2 from the patent, which depicts a wire with dielectric nubs (14, 22) creating cavities (20) to support a membrane layer (24) (Compl. ¶¶26-27).
Asserted Claims
Independent claims 1 and 9 (Compl. ¶¶28, 30, 59). Note: The provided Inter Partes Review Certificate (US 7,529,574 K1) indicates that claim 1 was cancelled in a post-filing proceeding.
Accused Features
The complaint alleges that the Dexcom G4 and G5 systems use a sensor with "at least two nubs of dielectric material" and a "membrane system comprising an enzyme that... surrounds the nubs" (Compl. ¶¶37-38).
III. The Accused Instrumentality
Product Identification
The Dexcom G4 Platinum System (“G4”) and the Dexcom G5 Mobile CGM System (“G5”) (Compl. ¶5).
Functionality and Market Context
The accused products are continuous glucose monitoring systems. The complaint alleges they consist of a sensor wire assembly for insertion under a patient's skin, a wireless transmitter attached to a sensor "pod," and an electronic receiver device (which can be a user's mobile device in the G5 system) (Compl. ¶33). Functionally, the systems are alleged to operate by producing an electric current via the inserted sensor, which is then translated into information reflecting the patient's blood glucose level (Compl. ¶34). Plaintiff alleges that Defendant derives most of its revenue from sales of these accused systems (Compl. ¶12).
IV. Analysis of Infringement Allegations
’202 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| (a) providing a sensor having: (i) a structurally flexible core having an outer surface; | The G4 and G5 systems allegedly "use a sensor comprising a structurally robust tantalum core." | ¶35 | col. 2:36-37 |
| and (ii) a layer of electrochemically active metal surrounding, covering, and in contact with said outer surface of said core; | The systems allegedly use a sensor with "a layer of platinum surrounding, covering, and in contact with the outer surface of the core." | ¶36 | col. 2:43-45 |
| (b) placing at least a portion of said sensor into said animal body; | The sensor wire is "designed to be inserted through a patient's skin." | ¶33 | col. 4:59-61 |
| (c) measuring any electric current produced by said sensor and forming a measurement of analyte concentration... | The systems "produce an electric current which may be translated... into information reflecting the patient's current blood glucose level." | ¶34 | col. 4:62-65 |
’433 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a structurally flexible core having an outer surface; | The accused systems allegedly use "a sensor comprising a structurally robust tantalum core." | ¶35 | col. 4:3-4 |
| a continuous layer of electrochemically active metal surrounding, covering, and in contact with said outer surface of said core, | The accused systems allegedly use "a sensor having a layer of platinum surrounding, covering, and in contact with the outer surface of the core." | ¶36 | col. 4:1-2 |
| wherein the electrochemically active metal prevents body fluid from contacting said core and has at least one sensing surface, | The platinum layer allegedly "prevents body fluid from contacting the core." | ¶36 | col. 5:60-62 |
| wherein said layer of electrochemically active metal is at least partially surrounded by a membrane system comprising an enzyme. | The accused systems allegedly use a sensor with "a membrane system comprising an enzyme that at least partially surrounds the electrochemically active metal." | ¶38 | col. 5:58-59 |
Identified Points of Contention
- Legal Question: A threshold issue for Counts I (’202 Patent) and III (’574 Patent) is the legal status of the asserted claims. Given that the asserted independent claims for these patents were cancelled in IPR proceedings that concluded after the complaint was filed, the court will need to determine if these counts have any surviving basis, for example through un-cancelled dependent claims.
- Technical Question: For the surviving ’433 Patent claims, a central question may be factual and evidentiary: what evidence demonstrates that the accused sensor's platinum layer is "continuous" and actually "prevents body fluid from contacting said core" as the claim requires? The complaint alleges this in a conclusory manner (Compl. ¶36) but provides no specific test data or structural analysis.
V. Key Claim Terms for Construction
For the ’433 Patent, whose asserted independent claim survived IPR:
The Term: "structurally flexible core"
- Context and Importance: The patent’s core innovation rests on combining a "robust" yet "flexible" core with a sensing layer. The definition of "structurally flexible" is therefore critical. Practitioners may focus on this term because its scope will determine whether the claim reads on a wide variety of core materials or is limited to materials exhibiting a specific degree of flexibility needed to solve the breakage problem described in the patent.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification lists several materials, including "tantalum, stainless steel or nitinol," as well as "polymeric material or a glass fiber," suggesting the term is not limited to a single class of metal (’433 Patent, col. 4:3-12). This could support an interpretation covering any core that is not rigid.
- Evidence for a Narrower Interpretation: The background section frames the invention as a solution to prior art sensors fatiguing and breaking from "bodily movement" (’433 Patent, col. 1:13-16). This context suggests "structurally flexible" might be construed more narrowly to mean possessing sufficient flexibility to withstand in-body flexure for days without material fatigue or fracture.
The Term: "prevents body fluid from contacting said core"
- Context and Importance: This is a negative functional limitation. Its interpretation is crucial because infringement hinges on whether the accused platinum layer provides a perfect, hermetic seal.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party might argue for a practical interpretation, where the term means the layer substantially prevents any fluid contact that would cause the "unpredictable electrical activity" that could "corrupt[] the measurement," a problem the patent links to fluid contacting the core (’433 Patent, col. 3:26-31). This would allow for microscopic imperfections that do not affect sensor function.
- Evidence for a Narrower Interpretation: The plain language "prevents" could be argued to be absolute, meaning any pinhole or imperfection that allows any amount of fluid contact would mean the limitation is not met. The specification warns that if fluid were to contact the core, "unpredictable electrical activity could result," supporting the view that complete prevention is required (’433 Patent, col. 3:28-31).
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for all three patents. Inducement is based on allegations of Dexcom’s "specific knowledge" of the patents and knowledge that its customers' use of the G4 and G5 systems would constitute direct infringement (Compl. ¶¶42, 51, 60). Contributory infringement is alleged based on selling or importing a component (the sensor) that is a material part of the invention and not a staple article of commerce (Compl. ¶¶43, 52, 61).
- Willful Infringement: Willfulness is alleged for all three patents, entitling AgaMatrix to trebled damages (Compl. ¶¶48, 57, 66). The complaint asserts this based on the same "specific knowledge" alleged in the inducement counts, without providing further factual detail regarding pre-suit notice or egregious conduct.
VII. Analyst’s Conclusion: Key Questions for the Case
- A dispositive threshold question is one of case viability: Following the cancellation of the asserted independent claims of the ’202 and ’574 patents in post-filing IPR proceedings, can Plaintiff maintain Counts I and III based on surviving dependent claims, and if so, can infringement be proven for those narrower claims?
- For the surviving claims of the ’433 patent, a central issue will be one of functional proof: What type of evidence will be required to prove the accused sensor's platinum layer "prevents body fluid from contacting said core," and does this claim language require an absolute, hermetic seal or merely a functionally sufficient one?
- The outcome will also likely depend on a matter of definitional scope: Will the term "structurally flexible core" be construed broadly to encompass any non-rigid core material, or will it be limited by the patent's background to require a specific, demonstrable resistance to the type of in-body fatigue and breakage the invention was designed to solve?