In G1/24 the Enlarged Board of Appeal of the EPO clarified that claims must be interpreted in light of the description when assessing patentability. However, it left open how this principle applies to added matter. Diverging approaches in the case law have since exposed a fault line in EPO practice: whether, and to what extent, the description should influence claim interpretation for assessing Article 123(2) EPC. The new referral in G1/26 asks the Enlarged Board of Appeal to address this issue, with potentially significant implications for drafting, amendment strategy, and opposition proceedings.
The referral in G1/26 not only seeks to resolve the uncertainty around added matter, but also to clarify when legal questions can be referred to the Enlarged Board of Appeal.
Mind the gap in G1/24
G1/24 dealt with a long-debated uncertainty in EPO case law: how far should the description and drawings be used to interpret patent claims? As discussed here, the Enlarged Board of Appeal decided that the claims remain central but must always be interpreted in light of the description and drawings when assessing patentability under Articles 52 to 57 EPC.
However, the decision failed to address added matter under Articles 76 and 123(2). An area where claim interpretation can have significant consequences for patent applicants and proprietors. This gap left by G1/24 has quickly become a focal point of uncertainty.
Implications of G1/24 and the current position
Since G1/24 was issued, it has, to date, been cited in a staggering 114 decisions of the Board of Appeal (for scale, G1/19 which related to the patentability of computer implemented inventions has been cited 150 times since it issued 5 years ago in 2021).
When added matter has been the issue at questions, most decisions have adopted a two-step test for assessing whether claims comply with Article 123(2):
- Step 1: interpret patent claims from the point of view of the skilled person.
- Step 2: Establish whether the subject-matter of the amended claim, as established by way of interpretation, contains subject matter which extends beyond the content of the application as filed.
This test may sound straight forward, but there are currently three distinct approaches to address step 1:
- Description consulted only to define the skilled person
The description is used only to identify the relevant technical field and the common general knowledge of the skilled person.
Under this approach, claims are interpreted broadly, and all reasonable meanings are considered unless they are illogical or make no technical sense. As a result, interpretation is limited only by logic and common general knowledge, and each possible interpretation must be assessed for original disclosure.
- No broadening or limitation of the claims based on the patent specification
This middle ground approach uses the patent specification to rule out interpretations that conflict with its technical context. However, they do not allow adding limitations from the description into the claims, nor do they accept overly broad interpretations when the claim conveys a clear and credible technical teaching to the skilled person.
- Holistic approach – interpretation in view of the patent specification as a whole
Under this approach the claims are interpreted in light of the entire patent (claims, description, and drawings) as a unified whole. This can justify either broadening or narrowing the meaning of a claim feature based on what a skilled person would understand from the specification.
Thus, conclusions differ depending on the way in which the claims are interpreted in step 1. This is because the interpretation of the claims depends on whether, and to what extent, the description is relied upon when interpreting the claims (i.e., whether approach 1, 2 or 3 is adopted).
A fork in the road
In the case of T873/24, from which the G1/26 referral originates, the three approaches outlined above result in three different outcomes.
Thus, the question arises as to what extent the description and drawings should be taken into account when addressing the specific question of added subject matter?
What is G1/26 actually about?
At the core of G1/26 is a deceptively simple amendment which was made during prosecution of the European patent EP3587104B1.
The patent relates to coated steel strips comprising inter alia nitrogen and titanium. In the application as originally filed, claim 5 specified that the weight ratio of titanium to nitrogen in the steel strip is in excess of 3.42. That is, both the components (Ti and N) and the unit (weight ratio) were clearly defined.
During prosecution, an amendment was made so that claim 1 specified that the ratio of titanium to nitrogen is in excess of 3.42, with no mention of “weight”.
The crux of the dispute centred around whether claim 1 as granted added matter.
On this point, the Opponent argued that without the unit being explicitly stated, it was no longer limited to a weight ratio. Rather, it could plausibly be interpreted as a molar ratio, a volume ratio, or another type of ratio altogether. In view of this, it argued that the amendment introduced matter which was not present in the application as filed because the application did not support a generalised ratio, only the specific weight ratio.
The Patent Proprietor, unsurprisingly, took the view that the amendment did not add matter. Looking at granted claim 1 as a whole, which also included the weight % of each component comprised in the steel strips, the only possible interpretation was that the ratio in the claim as granted had to be a weight ratio. They considered that the description reinforced this interpretation. Therefore, in the proprietor’s view, there was no added matter.
The Board of Appeal noted that the different approaches for assessing added matter (as outlined above) would result in a different outcome. If assessed under approaches 1 and 2, claim 1 would be found to add matter. Conversely, if the assessment was done under approach 3, it would be reasonable to conclude that claim 1 did not add matter, i.e., that it complied with the requirements of Article 123(2) EPC
In view of this contradiction – or divergence – the Board of Appeal considered a referral to the Enlarged Board of Appeal to be necessary.
Thus, the following questions were referred to the Enlarged Board of Appeal:
- Does the fact that the claims are the starting point and the basis for assessing the patentability of an invention generally preclude a feature which is only disclosed in the description or the drawings of a patent from being read into the meaning of a granted claim, in particular if this leads to a restrictive reading of terms used in the claim?
- If the answer to the above question is no: is claim interpretation the result of both reading the claims and consulting the description and drawings as a unitary process and does the claim being the starting point and the basis for assessing the patentability rule out only those interpretations which can be derived from the patent as a whole but would clearly contradict the general technical understanding of the terms used in the claim?
- When assessing compliance with Article 123(2) EPC, must a term used in a claim be assessed against all interpretations that make technical sense to the skilled reader on the basis of the claim alone?
- If the answer to the above question is no: is it sufficient that only the interpretations of the subject-matter of the claim established against the background of the patent specification as a whole are directly and unambiguously derivable from the application as filed?
Admissibility of referral
In addition to the substantive issues, G1/26 also raises an important procedural question about when a referral to the Enlarged Board is “required” under Article 112(1) EPC:
May a decision be considered to be “required” for the purposes of Article 112(1) EPC, if the referring Board demonstrates that the point of law in question arises out of the context of the case pending before it and, in the circumstances of the proceedings, it is reasonable for the Board to examine it and decide on it next?
Historically, referrals to the Enlarged Board of Appeal have only been considered admissible once a Board of Appeal has concluded that the patent would be maintained despite all other invoked grounds during proceedings.
In G1/26, the Board of Appeal argue that this strict and excessively formalistic approach leads to impractical and inefficient proceedings because it requires examination of every other possible objection before addressing a straightforward or fundamental point of law that has arisen in the case.
In this case, the issue is particularly acute because there are 107 auxiliary requests on file. Addressing the referred questions prior to assessing all of the auxiliary requests is considered by the Board of Appeal to be warranted in the interest of procedural economy, even where it cannot be excluded that the referred questions are irrelevant once all the other arguments of the parties have been dealt with.
In essence, the Enlarged Board is being asked whether Boards of Appeal can take a more pragmatic approach to referrals, addressing fundamental legal questions early rather than only as a last step after exhausting all other issues.
Next steps and practical consideration
It remains to be seen whether the Enlarged Board of Appeal will admit the referral in G1/26 and, if so, how it will choose to address the issues raised. For example, G1/25 (description amendments) has also stemmed from uncertainty in the wake of G1/24, so could both cases be considered together?
As to practical considerations, the importance of providing clear definitions – and thoroughly considering these definitions and the potential impact they may have on claim interpretation – cannot be overstated. As ever, it is critical to choose your words carefully!
