EPO v UPC: How the EPO’s and UPC’s approaches to validity give us food for thought when drafting and prosecuting patent applications destined for Europe (Part 2)

The Unified Patents Court (UPC) opened its doors on 1 June 2023 and is already having a significant impact on EPO practice. Less than a year after opening, the UPC Court of Appeal (CoA) rendered its decision in 10x Genomics vs. NanoString (UPC_CoA_335/2023), ruling on how claims should be interpreted under the European Patent Convention (EPC). The CoA’s position was at odds with the EPO’s “classical” approach. This inconsistency played an influential role in prompting the EPO to reconsider how claims should be interpreted. In June 2025, the EPO’s Enlarged Board of Appeal (EBoA) (G1/24) brought the EPO’s approach to claim interpretation closer into line with UPC’s, finding “it a most unattractive proposition that the EPO deliberately adopt a contrary practice to that of the tribunals that are downstream of its patents”.

The EBoA in G1/24 made the EPO’s harmonisation intentions very clear. However, harmonisation is not a new concept. When G5/83[1] issued some 46 years ago, the EBoA held that it was incumbent on the EPO to take the decisions of courts and industrial property offices in the EPC Contracting States into consideration. But G5/83 did little to promote harmonisation. However, since G1/24, there has been a palpable change, and we are beginning to see the EPO make significant strides to align its approach on validity with the UPC’s. Conversely, while the UPC is developing its case law independently of the EPO, many aspects of UPC case law have been shaped by the EPO’s approach to validity.

In this four-part series, we explore the similarities and differences between the EPO’s and UPC’s approach to claim interpretation, added matter, novelty, sufficiency and inventive step. As well as influencing litigation strategies, these similarities and differences give us food for thought when drafting, prosecuting and managing patent portfolios destined for Europe.

In the second part to this series, we take a detailed look at added matter, novelty, and sufficiency. The key takeaway is that the EPO’s and UPC’s approaches are closely aligned, and many European patent attorneys will find the expressions used by the UPC to justify their decisions on these issues very familiar.  This is not to say that outcomes will be the same all of the time. Traditionally, the Examining and Opposition Divisions and Technical Boards of Appeal (TBAs) of the EPO have placed a great deal of emphasis on the wording used in the text. Conversely, the UPC takes pride in its “holistic” approach when trying to understand what is being conveyed to the skilled person. Depending on the facts, this may occasionally lead to different outcomes despite the frameworks for assessing  added matter, novelty, and sufficiency being broadly the same.

Added Matter

Under Article 123(2) EPC, a European patent or patent application cannot be amended in such a way that it contains subject matter that was not contained in the application as filed. Accordingly, any amendment made must have basis in the original application. The EPO is notoriously strict when assessing added matter and applies the so-called “gold standard” (G2/10). Under the gold standard, an amendment can only be made within the limits of what a skilled person would derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing, from the whole of these documents as filed.

With the EPO’s gold standard, even if a feature is disclosed in the specification, it can sometimes be difficult to amend a claim to that feature if that feature is only disclosed in the context of a specific embodiment of the invention (intermediate generalisation). For such an amendment to be allowable, the feature cannot be inextricably linked to the other features of the embodiment. Moreover, the overall disclosure should justify its generalisation across the scope of the invention. The same rationale applies to any feature omitted from the amendment.

On the face of it, the UPC is aligned with the EPO when it comes to added matter. In Sibio v Abbott [UPC-CoA-884/2025], the CoA confirmed the approach in Abbott v Sibio in UPC_CoA_382/2024, referring to the EPO’s gold standard. Echoing the EPO’s approach to intermediate generalisations, the CoA in Sibio v Abbott considered whether it was permissible to omit a feature of a specific embodiment by considering whether the feature was inextricably linked to the other features in that embodiment.

However, while the UPC adopts the same legal tests as the EPO when considering added matter, there may be differences in the way the tests are put into practice. For example, as discussed above, the current uncertainties over how claims should be interpreted when assessing added matter at the EPO may give rise to differences between the EPO and UPC[2]. Moreover, when the UPC CoA in Sibio v Abbott considered whether an omitted feature could be generalised across the scope of the invention, the CoA considered the technical effect of the invention, and whether the omitted feature contributes to this effect and is essential to the invention. By way of contrast, the TBA in T25/03 considered whether isolated features were essential to the embodiment from which the features were isolated. As the specific embodiment may achieve an improved or a greater number of technical effects than the invention in general, it is possible for a feature to be deemed essential to a specific embodiment but not the invention in its most general form. Accordingly, depending on the facts of the case, it is possible that the UPC may apply the gold standard more leniently.

Overall, therefore, the EPO and UPC are broadly aligned on added matter as the same gold standard is applied. However, by placing emphasis on the technical effect of the invention, the UPC appears to take a more holistic view as to what the invention seeks to achieve and construes the purpose of features of the invention in this context. This differs from the EPO, which focusses heavily on the wording of the original text. Whether this results in the UPC applying the gold standard more leniently is likely to be dependent of the facts of each case. However, anecdotally under certain factual frameworks, the UPC may well have a more permissive attitude to added matter because of its holistic approach.

This potential difference should be borne in mind if parties are minded to challenge European patents post-grant, especially when a choice of forum still exists (e.g., if the 9-month opposition window is still open).  That said, the potential for divergence may diminish with time if the EPO continues to harmonise its approach with the UPC’s.

Table 2: Summary of EPO’s and UPC’s approaches to added matter

Novelty

The “gold standard” above has far reaching implications in EPO proceedings as the uniform concept of disclosure means that it is also used to assess novelty and priority (G2/10). The UPC CoA has endorsed this uniform concept at least in its approach to novelty.

For instance, in Fujifilm v Kodak [UPC_CoA_473/2025], the UPC CoA confirmed that novelty should be assessed based on what a skilled person, using his common general knowledge at the relevant filing or priority date, would derive directly and unambiguously from a single piece of prior art. While the disclosure of the prior art document in its entirety must be considered, the content of a prior art document could not be treated as a reservoir from which features may be drawn to create a particular embodiment. Moreover, while different passages of a document may be combined, this was only if there was a clear and unmistakable teaching suggesting this. The CoA also acknowledged that features may be disclosed implicitly, but this required the skilled person to consider such features to be a clear and unambiguous consequence of what was explicitly mentioned.

These concepts will be very familiar to European patent attorneys practising before the EPO; indeed, the phraseology used by the CoA in their judgments could have been cut and pasted directly from decisions of the TBA. However, as with added matter, differences in outcome may arise depending on how strictly the gold standard is applied. On paper at least, the UPC’s approach to novelty is closely aligned with the EPO’s. However, the UPC appears to adopt a more holistic approach when reviewing the prior art and places greater emphasis on the technical aims that the prior art document seeks to achieve. By way of contrast, the EPO traditionally places significant focus on the wording used. This may affect what might be deemed to be directly and unambiguously derivable from the text, particularly with respect to implicit disclosures or when considering whether parts of a prior art disclosure may be combinable in the absence of an explicit teaching to do so.

Table 3: Summary of EPO’s and UPC’s approaches to novelty

Sufficiency

Article 83 EPC stipulates that a patent or patent application shall disclose an invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. The sufficiency requirement is generally considered to be a key component of the patent bargain; a monopoly is granted to the patent holder in exchange for a disclosure of the invention in sufficient detail for it to be reproduced.

The case law of the EPO stipulates that the subject-matter of an application must be sufficiently disclosed at the effective date of the application, based on the application as a whole and taking into account the common general knowledge of the skilled person. When attacking a claim as lacking sufficient disclosure, the EPO places the burden on the party raising the insufficiency attack to present serious doubts, substantiated by verifiable facts, that a skilled person could not reproduce the invention. This can be a difficult burden to bear, as the sufficiency bar is met as routine tests are permissible to meet the requirements of sufficiency.

The UPC CoA largely endorsed the EPO’s approach to sufficiency in Sanofi v Amgen [UPC_CoA_528/2024]. Like the EPO, the CoA confirmed that one way of performing the invention was held to meet the requirements of sufficiency. The CoA also confirmed that the disclosure need not include specific instructions as to how reproduce every conceivable embodiment of the invention. Just as the EPO’s approach allows for the occasional failure (T931/91), the CoA held that the non-availability of some embodiments was immaterial to sufficiency, as long as the skilled person would be able to obtain suitable embodiments within the scope of the claim. Furthermore, the CoA confirmed that a reasonable amount of trial and error did not prevent the invention from being enabled.

The EPO’s and UPC’s approach to sufficiency appear to be aligned. However, although the claim in Sanofi v Amgen was a therapeutic use claim, the sufficiency objection was not based on an allegation that the claimed therapeutic indication was sufficiently disclosed. Often, in post-grant validity proceedings in the pharmaceutical field, this is the main point of dispute when sufficiency is called into question. For example, EPO case law requires the original application to provide proof that a drug has the claimed therapeutic effect, especially, if in the absence of experimental data in the application, it would not be credible that the therapeutic effect is achieved. The level of proof that is required is an open question and depends heavily on the facts. Nonetheless, this question is critical to validity because the absence of a credible effect cannot be remedied by post-published evidence (G2/21). It remains to be seen whether the UPC adopts the EPO’s approach to the question as to whether a therapeutic effect is rendered sufficiently credible to meet the requirements of Article 83 EPC.

Table 4: Summary of EPO’s and UPC’s approaches to sufficiency

[1] See Reasons 6 of G5/83

[2] G1/26

This article was prepared by Hsu Min Chung, Thomas Compton & Robert Scanes.

View Part 1 here

Part 3 coming soon.