Doubling Up on Added Matter at the UPC

Following the UPC Court of Appeal (CoA) decision in Abbott v Sibio (APL_39664/2024, 14 February 2025) we now have a second CoA decision on added matter in expert Klein v Seoul Viosys (UPC_CoA_764/2024 & UPC_CoA_774/2024, 2 October 2025).

expert Klein v Seoul Viosys is notable as the first judgment on added matter by the CoA on a substantive infringement/validity appeal.

Note – HGF Partner Bernhard Ganahl represented expert Klein together with  Dr. Dirk Jestaedt of KRIEGER MES.

Both decisions are from the same CoA Panel (same three Legally Qualified Judges, different Technically Qualified Judges), and both decisions overturn the Court of First Instance (CFI) on added matter.

One patent survived (Abbott). One did not (Seoul Viosys).

What can we learn about the UPC CoA’s approach to added matter?

The Test for Added Matter

As per the usual UPC approach to substantive matters, both decisions started by identifying the skilled person and discussing the patent at issue in detail.

Importantly, the next step was to identify the object of the invention as derivable from the Patent (Abbot v Sibio, [36] & expert Klein v Seoul Viosys, [33]).

The CoA then construed the claims, applying the test set out in NanoString v 10x Genomics (UPC_CoA_335/2023).

Turning then to added matter, both decisions applied the same test:

“There is added matter if the claim as granted contains subject-matter that extends beyond the content of the application as filed. In order to ascertain whether there is added matter, the Court must thus first ascertain what the skilled person would derive directly and unambiguously using his common general knowledge and seen objectively and relative to the date of filing, from the whole of the application as filed, whereby implicitly disclosed subject-matter, i.e. matter that is a clear and unambiguous consequence of what is explicitly mentioned, shall also be considered as part of its content. Where, as here, the patent is a divisional application, this requirement applies to each earlier application.”

Significantly, this test requires that the Court consider what the skilled person would objectively derive from the application as filed. This objectivity is through the lens of the common general knowledge and with consideration of the object of the invention. It is not an assessment of only what the application as filed states verbatim, but what the skilled person would understand when reading the application to ascertain how the object of the invention is achieved. The same approach is taken for claim interpretation and for assessing added matter.

The approach is closely aligned with national courts where the skilled person (and their common general knowledge) gives some leeway when considering the teaching of the patent. This is in contrast to EPO practice where there is typically less detail on the common general knowledge and where the EPO Gold Standard is generally considered a harsher test than at most national courts.

Different Outcomes

As noted above, after applying the added matter test in Abbott v Sibio the CoA decided that the claim did not define subject matter that extends beyond the content of the application as filed, and the patent survived.

In contrast, after applying the same test in expert Klein v Seoul Viosys the CoA decided that the claim did fall foul of this test, and the patent was revoked across the relevant states.

expert Klein v Seoul Viosys

The Seoul Viosys Patent (EP3926698) relates to flip-type LEDs formed on semiconductors, and in particular to an arrangement of layers, mesa etched areas, mesas and openings that improves the current distribution through the LED and provides more homogenous light emission.

Claim Interpretation

In the decision, the CoA determined the object of the invention as how to improve the current spread and light output of LEDs [33]. This was based on what the skilled person would understand from the patent and using their common general knowledge.

After stating this, the CoA focussed on the claim interpretation of one particular feature: 5.2: “Openings […] arranged near an edge of the substrate”.

When interpreting this feature the CoA discussed the purpose and effect of this feature and how it contributes to the object of the invention. Based on this, the CoA concluded that some embodiments of the Patent (Figures 24-26) are not covered by claim 1. The reasoning is that the arrangements of the mesas and mesa etched areas illustrated and described in these embodiments do not achieve the object of the invention [51].

This was in contrast to the CFI decision and, as we will see below, is important for added matter.

Added Matter

In the added matter section the CoA first agreed with both parties and the CFI that claim 1, in defining a plurality of mesa etched areas, covered LEDs having only a single mesa [55]. Note that claim 1 does not directly recite mesa(s), but the presence of at least one mesa is implicit from the claimed plurality of mesa etched areas.

The CoA then explained why the original application did not provide disclosure of an LED with a single mesa [66] – [78].

The Patentee had argued that some embodiments of the original application disclosed an LED with a single mesa. In particular, they referred to the embodiments of Figure 24-26. However, the CoA found that the description of these Figures was linked to other Figures in the original application and that the skilled person would understand that these embodiments did include a plurality of mesas.

For this reason alone the CoA found that the claim was invalid for added matter [84].

Additionally, as noted above, in the claim interpretation section the CoA had already found that these same embodiments (Figures 24-26) did not disclose feature 5.2 of the claim.

So, the CoA then explained that even if the embodiments of Figures 24-26 were considered to disclose an LED with a single mesa, the claim still added matter because these embodiments did not include feature 5.2 of the claim [85] – [99].

In summary, the CoA essentially concluded that the claim added matter because:

• it covered LEDs with only a single mesa, which were not derivable from the original application, and
• even if LEDs with a single mesa were derivable from the original application, they were not disclosed in combination with another feature (5.2) of the claim.

It is notable that the key features for claim interpretation and added matter were both important for achieving the object of the invention. When discussing these points the CoA focussed on what the skilled person would objectively derive from the application as filed when trying to understand how the object of the invention is achieved.

Abbott v Sibio

In Abbott v Sibio the question on added matter was one of intermediate generalisation. Sibio argued that claim 1 omits certain features that are disclosed in combination with the features of claim 1, thus resulting in an unallowable intermediate generalisation. This was the winning argument at the Court of First Instance. However, the Court of Appeal overturned this.

The principle reasons behind the CoA’s decision are that: (i) the skilled person would not have derived any particular advantage from the omitted feature, and (ii) the omitted feature does not contribute to, and is not relevant for, achieving the object of the invention [75].

Although the CoA does acknowledge that the omitted feature has some importance to the functioning of the product, it does not contribute to the object of the invention and anyway the original application provides alternatives to the specifics of the omitted feature. As such there is no inextricable link between the claimed and omitted features [78].

As a result, omitting this feature is not an intermediate generalisation.

Some comment has noted that the claim does not even define the omitted feature at a general level, so the decision does seem odd because it is not only that the specific feature is not tied to the claimed feature, but also at a more general level.

However, it seems that the CoA primarily considered whether the omitted feature contributes to the objective of the invention, and secondarily whether there was anyway an inextricable link between the two features. The Court answered no to both these questions, and as such found no intermediate generalisation.

Similarities and Differences

It is notable that the same test was applied in both decisions, and it is interesting to see the key factors that swayed the decisions in opposite directions.

The distinction between appears to come down to whether the key feature of the added matter argument is construed as contributing to the object of the invention. If it does, then the line of reasoning seems similar to the EPO Gold Standard (i.e., quite harsh). In contrast, where the feature does not contribute to the object of the invention and is not otherwise presented as essential or particularly advantageous, the skilled person may be able to separate parts of the original disclosure without there being an intermediate generalisation.

More to Come

It will be interesting to see further UPC CoA decisions on added matter and how the test develops, and in particular whether other CoA Panels will apply and follow the same logic.

This article was prepared by Partner & Patent Attorney Scott Fletcher.