Court of Appeal focuses on the technical effect to determine added matter

Background

Sibio Technology Limited brought revocation proceedings against Abbott Diabetes Care Inc.’s patent EP3831283 for an on-body glucose monitoring device in the Paris Central Division in May 2024, after Abbott first made an application for a preliminary injunction restraining Sibio, and its European distribution partner, Umedwings Netherlands B.V., from infringing EP ‘283 with their GS1 continuous glucose monitoring device.

Abbott’s application for provisional measures was refused by the Hague Local Division, as they found that EP ‘283 was more likely than not to be held invalid due to added matter,¹ but this finding was subsequently overturned by the Court of Appeal, who consequently granted a preliminary injunction restraining Sibio/Umedwings from committing any infringing acts.²

The patent was then subsequently found valid in the first instance revocation proceedings in a July 2025 decision from the Paris Central Division.³ Sibio contested this decision on appeal, asserting that EP ‘283 should have been found to be invalid for added matter and lack of inventive step.

The Court of Appeal upheld the first instance decision, rejecting Sibio’s arguments on both the added matter and inventive step issues, confirming their approach to assessing added matter at the UPC.

The contested claim feature

Claim 1 of EP ‘283 is directed to an on-body device comprising a glucose sensor assembly, an enclosure, and sensor electronics positioned within the enclosure. The claim requires the presence of a recess in the base portion of the enclosure, comprising an opening in a bottom exterior surface, through which a connector support (which electrically couples the glucose sensor to the sensor electronics) is received.  In some embodiments described in the application as filed, the recess is described as including an elastomeric sealing member (or unit), which acts to seal the connection between the sensor assembly and the electronics assembly, but this feature is not included in the granted claim.

Sibio asserted that the exclusion from Claim 1 of an elastomeric sealing component within the recess constitutes added matter, either because it amounts to an intermediate generalisation or because the claim omits an essential feature of the invention.

Intermediate generalisation or a missing essential feature?

Under EPO practice, an intermediate generalisation arises when one or more specific features are isolated from the other features of embodiment(s) in the context of which they are disclosed and used to limit the claimed subject matter. Such amendments will often lead to a finding of added matter but may be allowable if it can be established that the claimed subject matter meets the “gold standard” requirement of being directly and unambiguously derivable from the application as filed. Compliance with this standard is usually determined by establishing that there is no inextricable link between the isolated feature(s) and the embodiment(s) from which they are extracted, and that the overall disclosure of the patent justifies the generalising isolation of the relevant feature(s).

The omission of an essential feature of the invention can also lead to added matter at the EPO, and a three-step “essentiality test” is sometimes used to determine whether or not a feature can be allowably omitted on this basis. However, in recent years, Boards of Appeal have preferred to focus on compliance with the gold standard more broadly, rather than applying the specific test.

Alongside the argument that the inclusion of the recess without requiring the presence of an elastomeric sealing component amounted to an unallowable intermediate generalisation, Sibio included, as a separate category of added matter, the further argument that elastomeric sealing within the recess is essential in view of the function it performs and the technical effect to be achieved.  However, in paragraph 34 of the decision, the Court of Appeal rejected this separate categorisation of how added matter can arise and emphasised that the only relevant test is whether Claim 1 (as a consequence of the omission of elastomeric sealing) contains subject matter that extends beyond the content of the application as filed.

The technical effect of the invention is central

The Court of Appeal went on to explain that the technical effect that an invention aims to achieve, and whether an omitted feature contributes thereto, is relevant for the assessment of added matter. In particular, it considered that these factors would be relevant when considering whether the skilled person would understand from the disclosure of the application as a whole that there is a structural or functional relationship between the omitted features and the other features of the claimed invention, which the Court considered could alternatively be described as whether there is an inextricable link between the features or if the omitted feature is essential to the invention.  In other words, the Court of Appeal’s view was that the ostensibly alternative approaches to the assessment of added matter advanced by Sibio seek to answer fundamentally the same question, i.e. whether the claimed invention contains subject matter that extends beyond the content of the application as filed, and that understanding the technical effect underlying the invention is central to this assessment.

Following this approach, the Court found that the skilled person would not consider the feature of the elastomeric sealing in the recess of the enclosure of the electronics assembly to be necessary to achieve the technical effect of Claim 1.

The Court considered that the invention of Claim 1 arises from the specific configuration for an on-body glucose monitoring device in which the sensor assembly and the electronics assembly are already coupled – which configuration makes it possible for the applicator used to install the on-body device to move freely across the skin surface before applying the device in a single step.

The sealing of the components of the on-body device, or specifically the use of an elastomeric sealing in the recess of the enclosure of the electronics assembly, was not considered to be functionally related to the other features of Claim 1, or the technical effect which they collectively achieve, as sealing only serves the function of protecting the electrical connection between the components, which would be a common characteristic of all types of sealing mentioned in the application.  The Court also did not consider the sealing of the components in general, or the use of an elastomeric seal specifically, to be structurally related to other features of Claim 1.

The application as a whole must be considered

Sibio attempted an argument that only the embodiments falling within the granted claims should be considered when assessing added matter, but the Court rejected this premise, and emphasised the need to consider the application as filed as a whole.  Passages of the application that do not relate directly to the claimed embodiment may also provide relevant information to aid in the skilled person’s understanding of the invention.

Finding on added matter and conclusions

The Court of Appeal then went on to find that, although the claim did not explicitly require the presence of any type of sealing of the of the electrical contacts of the different components of the device, the skilled person would understand sealing to be required in order to protect the connection, and avoid any disruption caused by dirt or moisture, essentially finding the general requirement for sealing to be implicit.  However, this sealing could be achieved through any of the various sealing methods described in the application, with no advantage being attributed to the use of elastomeric sealing.  Therefore, the omission of an explicit reference to sealing did not convey new technical information, and neither did the specific omission of elastomeric sealing.

This decision confirms that intermediate generalisations of the embodiments described in the specification can lead to added matter at the UPC.  However, the emphasis on the technical effect and how the relevant claimed and unclaimed features interact suggests a generally applicable approach for determining compliance with the gold standard that has the potential to be more forgiving that the EPO’s typical focus on the specific language included in and excluded from the claims.