High Court ruling clarifies patent validity and infringement in Abbott vs. Dexcom case.

Citation: [2024] EWHC 36 (Pat)
Judgment on


The recent ruling in the High Court of Justice concerning patents owned by Abbott Diabetes Care Inc & Ors v Dexcom Incorporated & Ors provides a comprehensive view of the legal principles surrounding patent validity and infringement. The case, presided over by Mr. Justice Mellor, involved allegations of infringement of various patents in the field of Continuous Glucose Monitoring (CGM) devices. The judgment elucidates on the nuances of assessing anticipation (novelty) and obviousness of patent claims, amendment allowability, and infringement determinations. This article aims to distill the key topics and legal principles discussed in the case, providing legal professionals with a clear analysis of the judgment’s foundations and outcomes.

Key Facts

The case involved multiple patents related to CGM technology:

  • EP627, focused on a method and apparatus for providing user notifications without disruption.
  • EP223, related to hosting safety-critical applications on uncontrolled data processing devices.
  • EP159 and its divisional EP539, concerning systems and methods for providing sensitive and specific alarms.

The dispute centered around whether certain Dexcom products infringed the aforementioned Abbott patents and if these patents were valid in light of prior art and other legal challenges.

The judgment in this case applied several legal principles vital to patent law:

Novelty (Anticipation)

The court examined whether prior art disclosures ‘planted the flag’ — a clear and unambiguous disclosure of all features in the claimed invention. The ‘Challenger launch decision’ analogy was employed to caution against hindsight bias, where post-event knowledge might unjustifiably influence the perception of what was known at the time of invention.

Inventive Step (Obviousness)

Assessment of obviousness was guided by the Supreme Court decision in Actavis v. ICOS, examining whether the idea of the invention would occur to the unimaginative skilled person as a technical solution. The role of uncertainty and unfamiliarity was noted as possibly deterring conception of the invention. The ‘one-way street’ concept indicated that if only one route of research was apparent, the invention’s outcome might be more likely to be obvious.


Assessment of amendments for allowability focused on whether they introduced restrictions or extended the scope of protection, along with considerations of clarity and conciseness under the Patents Act 1977.


The court analyzed infringement based on the proper construction of claims, examining if the accused products fell within the scope of the patented technology.


The court found:

  • EP627 lacked novelty due to anticipation by the STS Guide but was not obvious over another prior art, Bunte. If valid, it would be infringed by Dexcom’s products.
  • EP223, although not obvious over Lebel, was anticipated by Gejdos, rendering one of its claims invalid. The proposed amendments to EP539 were not allowable due to an extension of protection and lack of clarity.
  • EP159 and EP539, as amended, were anticipated by both Brauker and Shariati. If not anticipated, the patents would be obvious over the cited prior arts. Admitted infringement would apply if either patent had been valid.


The High Court’s meticulous review of the Abbott vs. Dexcom case reaffirms the complexity of patent litigation, especially concerning the nuanced readings of prior art and patent claims. The ruling serves as a testament to the importance of understanding the fine line between novel invention and public domain, the appropriate application of legal tests for obviousness, and the careful scrutiny amendments must undergo. The legal principles expounded within this judgment will undoubtedly serve as a valuable precedent for assessing patent validity and infringement in the UK.

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