Review of key EPO Case Law from 2023

Review of key EPO Case Law from 2023

Earlier this year, Tom Hailes, Jess Duncombe, Alex Worley, Scott Finlayson and Mark Abthorpe presented a webinar reviewing some of the most influential case law emerging from the EPO in 2023.  Here, we briefly recap some key take-aways and practice points. 

In this article: 


Added subject matter and novelty 

T 1099/21: “Result to be achieved” language and added subject matter 

At the EPO, clarity objections for features which define the invention in terms of a "result to be achieved" are quite common. In T 1099/21, the Board considered whether a claim filed with a functional definition that defines the invention in terms of a result to be achieved can be amended to replace this definition with a numerical parameter without adding new subject matter.  

Here, the application as filed included a composition claim with a functional upper limit for a compound concentration defined in terms of a desired end result. During prosecution, in response to an EPO clarity objection, this was replaced by a numerical upper limit. The Board found this amendment added subject matter because the application did not disclose that the numerical limit corresponded to the functional one, or that the functional limit was always complied with up to the numerical limit. 

The Board in this decision was largely unsympathetic to the applicant's predicament, emphasizing it is the applicant's responsibility to avoid any ambiguity. A clear takeaway is to be wary of this "clarity/added matter trap" when drafting; the decision emphasises the importance of setting out clearly which technical features lead to a functionally defined result. While functional definitions may seem like an attractive option for achieving broad claim scope, they can backfire if not used carefully. 

T 88/21: Undisclosed disclaimers are not a magic bullet to fix priority and novelty issues over your own prior art 

The Board considered in T 88/21 whether an undisclosed disclaimer can fix priority entitlement and restore novelty over an applicant's own earlier application. An undisclosed disclaimer, which is a proviso that was not present in the application as filed, is only permitted in exceptional situations, such as restoring novelty over "novelty-only" prior art under Art. 54(3) EPC. 

In T 88/21, the timeline of events was: 


D1, cited against the application and filed by the same applicant, disclosed subject matter within the scope of claim 1 of the application. The Board found claim 1 not entitled to priority because P1 was not the "first application" by the applicant for that subject matter (a requirement for valid priority).  

Since claim 1 was not entitled to priority, its effective date became the filing date. D1, published between P1's filing date and the application's filing date, was therefore no longer “novelty-only” prior art under Art. 54(3) EPC, but became “full” prior art under Art. 54(2) EPC. The applicant tried to fix this problem with an undisclosed disclaimer of D1's subject matter, arguing the disclaimer made P1 the “first application” again for the claimed subject-matter, entitling claim 1 to its priority date, and reducing D1 to a novelty-only Art. 54(3) prior art document. 

The Board disagreed, stating that priority and Art. 54(3) EPC status must be assessed before adding the disclaimer. Without priority entitlement, D1 remained Art. 54(2) EPC prior art, making the introduction of the disclaimer unallowable. 

So, when it comes to self-collision problems with an applicant’s own prior art, an undisclosed disclaimer may not solve all the problems, and given their strict allowability requirements, they should be a last resort. 

By Tom Hailes 


Update on the application of G 2/21 – what is needed in order for post-filed data to be admitted?  

A hot topic ever since the written decision published in March 2023 is how the new test laid down in G 2/21 will be applied by the Boards of Appeal.  In G 2/21, the Enlarged Board stated that post-filed data in support of a technical effect could not be disregarded merely for the fact it is filed after the filing date, but that an applicant can only rely on a particular technical effect for inventive step if that technical effect is: 

“encompassed by the technical teaching and embodied by the same originally disclosed invention [as the application as filed]” G 2/21, Headnote 2. 

In looking at cases that applied this new test in 2023, some themes have begun to emerge: 

  1. A bare assertion of the technical effect in the application as filed can be sufficient… 

In T 873/21 and T 728/21, a bare assertion of a particular technical effect in the application as filed was enough to justify the admittance of post-filed data.  These applications did not contain any experimental data evidencing the technical effect, but did contain general statements of the technical effect, such as: 

“The combination therapy according to the present invention advantageously leads to improved insulin sensitivity” (from the application in T 873/21)

What seemed to be at least partly determinative for the Boards was that, in both T 873/21 and T 728/21, the asserted technical effect could be clearly linked to the claimed subject matter under appeal.  In T 873/21, the Board noted that the claimed combination was clearly the preferred one in the application as filed, while in T 728/21 the Board pointed out that claim 1 in the opposition proceedings corresponded more or less exactly to claim 4 of the application as filed.  In both cases, the Boards highlighted that the asserted technical effect could therefore be clearly associated with the claimed subject matter.  This seemed to be persuasive, in particular when considering whether the asserted technical effect was “embodied by the same originally disclosed invention”. 

  1. …but the disclosure of the technical effect should be specific to the claimed embodiment 

On the other hand, a general statement of a technical effect in the application as filed was not enough to justify the admittance of post-filed data in T 852/20.  In this case, the proprietor asserted a technical effect of improved solubility of a particular crystalline form of a compound relative to a second crystalline form.  The application as filed stated in general terms that the application provided compositions with improved solubility (in a manner not dissimilar to that in the cases above).  However, the Board in T 852/20 considered that the skilled person would understand the general statement in the application to be in relation to amorphous compounds having improved solubility over crystalline forms, and not one crystalline form being improved over another.  On that basis, the proprietor could not rely on this technical effect for inventive step and the post-filed data was not admitted. 

Together, these cases illustrate that whether an asserted technical effect is “encompassed by the technical teaching” may not just come down to whether the application merely mentions the technical effect, but whether it is mentioned specifically in relation to the subject matter now being claimed. 

By Jess Duncombe 


Description amendments at the EPO 

A host of cases have passed through the EPO Boards of Appeal over the last few years conflicting on the degree to which applicants are required to amend the description of their applications. In practice, during examination, the requirements to amend the description in line with the claims can also vary in how strictly they are applied. 

We now have the opportunity to watch the conflict be resolved by an Enlarged Board of Appeal in a referral on the case of T 56/21. Board 3.3.04 have pointed out how the Guidelines on this practice have been made stricter since 1978, but want to know how this should be applied. Should we follow a strict approach like that in T 3097/19, or a more relaxed approach endorsed by T 2194/19? These questions will hopefully be answered if this case can make it to the Enlarged Board. I think we are owed some clarity. 



If you blinked, you might have missed it! There was a mini furore last year when it seemed that electronic signatures on assignment documents were not going to be allowed because of a negative decision from a Legal Board of Appeal in J 5/23. However, there is no need to fret; the EPO have cleared a path for assignments to be allowed even if they have a text string, electronic, or facsimile signature. In fact, the EPO won’t even be checking the authority to sign. It is still important to ensure that the transfer documents meet the legal standard for the jurisdiction whose laws apply to the transfer, but you’ll now have one fewer hurdle to register a transfer at the EPO. 

By Alex Worley 


Playing by the Rules (of Procedure of the Boards of Appeal) 

The current Rules of Procedure of the Boards of Appeal (RPBA) have been in place since 2020. The decisions published in 2023 explored a nuance of the rules around the status of auxiliary requests from opposition, and confirmed that the rules for filing your “complete case” on appeal really are as strict as they appear. 

First, in T 364/20 and T 1800/20, the Boards needed to consider the status of auxiliary requests filed during opposition proceedings but not examined by the Opposition Division (because the patents in each case were upheld on the basis of a higher request). In particular, the Board in each case had to decide whether, in appeal proceedings, these auxiliary requests constituted an amendment to the proprietor’s case, meaning that their admissibility was at the Board’s discretion. The Board in each case noted that while these auxiliary requests were not part of the decision under appeal, if they had been admissibly filed and maintained in opposition proceedings, then their filing again in appeal could not constitute an amendment to the proprietor’s case under the RPBA.  

So, were they admissibly filed during opposition proceedings? The Boards decided that to answer this question they had to step into the shoes of the Opposition Divisions and apply their principles, not those of the RPBA. The net effect was that in T 364/20 the auxiliary requests were admitted, while in T 1800/20 the auxiliary request in question was not, since it was late-filed and not convergent with higher ranking requests, i.e. it was not considered admissibly filed during opposition proceedings.  

Second, in T 1731/19 and T 1041/21, the Boards considered whether the proprietors’ auxiliary requests were substantiated, and therefore whether they were admissible. The proprietor in T 1731/19 simply said that their auxiliary requests 1-3 corresponded to those filed before the Opposition Division. The Board thus decided that they were not substantiated. The proprietor in T 1041/21 went a little further and referred to three submissions made during opposition proceedings, identified by their dates. However, this was not enough for the Board, who took the view that neither the other parties nor the Board could be expected to compile the proprietor’s arguments for 13 auxiliary requests from the three cited written submissions. The message from the Boards was clear: the statement of grounds of appeal / the reply must contain a party’s complete case, including how the auxiliary requests address the objections against the higher request(s); a reference to submissions made during opposition proceedings is not enough. 

By Scott Finlayson 


Oral proceedings by video conference at the Boards of Appeal​ 

Our clients often ask us “Will the oral proceedings on my appeal case be held by video conference or in person?” The answer is not clear-cut. On the one hand, the Boards’ own rules give themselves freedom to hold oral proceedings by video conference at their discretion. On the other hand, the Enlarged Board of Appeal in G 1/21 appeared to curtail that freedom, deciding that Boards could only refuse a party’s request for in-person oral proceedings during a general emergency (e.g. when COVID restrictions are in effect). Perhaps unsurprisingly, different ways of resolving the tension between these provisions have emerged. 

First, on the side of video conference oral proceedings, 2023 gave us a series of decisions from Board 3.2.01 (T 1158/20, T 758/20, T 618/21​). One of the parties in each case strongly objected to oral proceedings being held by video conference on the basis that the general emergency required by G 1/21 was no longer present, and on the basis of technical reasons including: 

  • They couldn’t compare figures side-by-side or draw freehand sketches during the oral proceedings in the way that they would have done on a flipchart, and 

  • The communication in a video conference is not as good as in person; it’s less direct and does not involve body language and facial expressions. 

The Board swept these objections aside. They took the view that G 1/21 was predicated on the position that video conference was an inferior format for oral proceedings as compared to in-person, which, while true when the referral that led to G 1/21 was made, was no longer the case. Consistent with this position, they decided that the cited technical reasons were not barriers to holding oral proceedings by video conference: Zoom allows screen sharing to compare figures / draw freehand, and body language and facial expressions are at least as visible, if not more so, by video conference. 

Second, on the side of in-person oral proceedings is a decision from Board 3.2.06 (T 2432/19). This Board, unlike Board 3.2.01, took the positions that the criteria of G 1/21 continue to apply and that video conference remains inferior to in-person oral proceedings in a number of respects. These include some aspects of body language not being visible by video conference, and the use of a common flip chart for all the parties being the best way to draw, develop and discuss sketches. Overall, the Board appeared to consider that a free-flowing debate between the Board and the parties is stymied by holding it over video conference; the immediacy is lost. 

So, how do we answer the question with which we started? “It depends” is the murky response, certainly on the Board and perhaps on your case. So, a better answer is “Ask your EP counsel!” As the above decisions (and others) show, if you’re familiar with the Board you can make a well-educated prediction as to whether you’ll need to book travel or a videoconferencing room. 

By Mark Abthorpe

If you would like to discuss this further, please get in touch with Mark Abthorpe, Alex WorleyScott Finlayson, Jess Duncombe, Tom Hailes or your usual Kilburn & Strode advisor.

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