Phew. Having only just reported on the latest application of decision G 1/24 of the European Patent Office (EPO) Enlarged Board of Appeal (EBA), things take a yet murkier turn with another related referral to the EBA now being reported.

The appeal concerned is T 873/24, and the question reportedly being referred to the EBA by the Board of Appeal concerns whether/how decision G 1/24 applies to the assessment of added matter (Article 123(2) EPC), and extension of subject matter in divisional applications (Article 76 EPC). 

In the patent in suit, EP3587104, a ratio of chemical elements is specified in claim 1 of the patent as granted with no units, whereas in the original application and the parent and grandparent applications, the ratio is expressed by weight. The opinion of the Board of Appeal was that this omission is an impermissible broadening that left the claim open-ended. The patentee argued that, according to decision G1/24, the description must always be consulted when interpreting the scope of the claims, and that a skilled person reading the description would clearly understand that the content of any chemical element was expressed in weight percent.

The plot indeed thickens. The EBA questions are yet to be referred, so we will need to wait to know precisely what is being asked. However, some initial observations are:

• On Day 1 of Patent School, trainees are told that when drafting/preparing amendments, you always use the same words to refer to the same feature. If you use different words, then the presumption is that a different meaning is intended. Thus, if the intention is to refer to "wt%" then say so. The same term should have the same meaning throughout the specification.
• If you aren't going to consult the description to determine questions of added matter, then where else are you going to look?
• If you are arguing against an allegation of "added matter" at the EPO on the basis that, even though there is no verbatim basis for a feature or combination of features in the specification as filed, a skilled person would nevertheless read the specification as disclosing this feature/combination, then in this author's experience you aren't going to win.