Abbott Diabetes Care Inc & Ors v Dexcom Incorporated & Ors

A patent claim must be construed purposively, but general claim language should not be restricted by importing limitations from a particular embodiment. A broad claim may nevertheless be limited by its express wording and technical context.

For novelty, the prior art must clearly and unambiguously disclose every claim element. For obviousness, the question is whether the inventive idea would occur to the uninventive skilled team, assessed without hindsight and in the context in which the team would read the prior art.

Patent amendments are impermissible where the amended claim extends protection or lacks clarity. A claim may be anticipated even where its broad wording encompasses an embodiment wider than the patent’s preferred examples.

These proceedings concerned four UK patents used in continuous glucose monitoring systems. Abbott alleged infringement of EP627 and EP223 by Dexcom’s G6, G7 and Dexcom ONE systems. Dexcom alleged invalidity for lack of novelty, inventive step and insufficiency. Dexcom also alleged that EP159 and EP539, concerning combinations of current and predictive hypoglycaemia alarms, were invalid. Abbott admitted infringement of EP159 and EP539.

The court considered claim construction, infringement, novelty, inventive step, proposed amendments to EP539, and the effect of the pleaded cases. The central issues included whether broad software and alarm-related claims covered the alleged implementations and whether the cited prior art clearly disclosed, or made obvious, the claimed combinations.

1. EP627. The claim was deliberately broad. A predetermined routine required execution on the receiver unit, association with an analyte monitoring device, interaction with its user interface, execution without interruption during the first indication, and completion before the second indication. The second indication had to include a predetermined alarm, but it did not have to operate as a reminder or be more permanent than the first indication. The G6, G7 and Dexcom ONE systems would infringe if the patent were valid. The claim was anticipated by the STS Guide, which disclosed the relevant sensor-expiry routine and notifications. It was not obvious over Bunte, because Bunte concerned notifications from an application unrelated to the application being used and therefore required hindsight to apply it to an analyte monitoring system.
2. EP223. A safety critical application was software whose failure or malfunction might cause significantly detrimental consequences, including death or injury. An installation check had to be performed after installation and could not be satisfied by a pre-installation signature check. A functional check was not confined to direct testing of the application’s functions; the broad claim wording included the G6 time check. The claimed selective enablement required the implementation to be capable of disabling safety-critical features while enabling non-safety-critical features following failure of either the installation or functional check. Claim 1 was anticipated by Gejdos. It was not obvious over Lebel. Claims 7 and 9 were obvious over claim 1. The pleaded infringement case failed because the relied-on installation check occurred before installation and did not produce selective disablement.
3. EP539. As granted, claim 1 concerned two current alerts, one settable and one fixed. The proposed amendment was intended to introduce a predictive threshold, thereby extending protection. It was therefore impermissible. The amended wording also lacked clarity because it referred to a predicted future real-time glucose value and created uncertainty about the relationship between the threshold and the time horizon.
4. EP159 and EP539. Both patents were anticipated by Brauker and Shariati, which disclosed user-settable current alarms and fixed-threshold predictive alarms in combination. Even if novelty had been established, the claims were obvious over Brauker, Shariati, the STS-7 Guide and the Navigator Guide. The additional temperature-correction, differentiated-output and visual-target-range features were disclosed or obvious. The claims were therefore invalid; infringement was admitted.