Yesterday, 12th March 2025, the Enlarged Board of Appeal (EBA) held the oral proceedings for referral G 1/23. G 1/23 seeks to clarify whether or not a commercially available product must be reproducible to form part of the state of the art within the meaning of Article 54(2) EPC. For an overview of the referred questions, see our previous note.

The referral arose from appeal proceedings relating to European Patent No. 2626911 (Mitsui Chemicals), which was opposed by Borealis AG. Key to the outcome of this case is whether the commercially available polymer, ENGAGE® 8400, is part of the state of the art despite not being easily reverse engineered.

Representatives for Mitsui and Borealis both presented arguments at the EBA hearing. Representatives for the EPO President also contributed. Prior to the hearing, and following the submission of various amicus briefs, the EBA issued a preliminary opinion (largely in line with the majority of amicus briefs), which provided some insight into how it might rule on this matter. However, the EBA did not provide any comments, nor did they ask any questions during the hearing, so we cannot know whether their view was swayed by the oral submissions of the parties.

The parties’ submissions

The Board opened the hearing by summarising the parties’ previous submissions. The Board noted that the referring Technical Board’s finding on inventive step in the appeal hinges on the question of whether the product ENGAGE® 8440 can be considered state of the art and that answering this question depends on the interpretation of G 1/92. The Board was therefore satisfied that an answer to at least some of the referred questions was required. The Board then outlined the referred questions and instructed the parties to present arguments in three rounds: first, admissibility of the appeal and interpretation of the referred questions; second, comments in relation to the first referred question; and third, comments in relation to the second and third referred questions. The parties then took the floor.

Admissibility of the appeal and interpretation of the referred questions

Submissions on this point were brief, and the parties largely referred to their previous written submissions. In particular, Borealis (Opponent) argued that the appeal is admissible given the divergence in case law and the importance of the answers to the questions on the referring appeal proceedings. They offered no further comments on the interpretation of the referred questions.

Mitsui (Proprietor) had no further comments on admissibility. However, they did request that the Board provides clarity on what a “product” is, in the sense of the referral. Mitsui argued that a “product” in the questions is a man-made product, and not an isolated product from nature.

The EPO President’s representatives offered no comments on this point and referred to their written submissions.

Comments in relation to the first referred question

Is a product put on the market before the date of filing of a European patent application to be excluded from the state of the art within the meaning of Article 54(2) EPC for the sole reason that its composition or internal structure could not be analysed and reproduced without undue burden by the skilled person before that date?

Borealis argued that the answer to the first referred question should be no, as there is no legal basis in the EPC requiring that a commercial product made available to the public should be reproducible (i.e., that the disclosure is enabling) to form part of the state of the art. On G 1/92, Borealis argued that neither of the questions considered in that case related to reproducibility and that the Enlarged Board was being asked to consider a different question in this case. Further, Borealis argued that that a reproduction requirement would introduce subjectivity into the test for novelty, which would be contrary to legal certainty.

Mitsui argued that the answer to the first question should be yes, because there is an enablement requirement for a written disclosure to form part of the state of the art and there is no reason that the same principles should not be applied to products also. Mitsui also argued that the requirements for disclosure are the same for Articles 54 and 83 EPC and so a commercially available product must be enabled in the same manner as an invention. In its arguments, Mitsui emphasised the “patent bargain” – that a proprietor is rewarded with a monopoly for sharing their invention with the public – and suggested that placing products on the market did not enrich the public knowledge in the same way if the product couldn’t be reproduced. Consequently, Mitsui argued that these products should not be considered as part of the state of the art and could be eligible for patent protection.

The representatives for the EPO President agreed with Borealis and argued that the answer to the first referred question should be no. They noted that although there is no legal difference between written documents and products, a practical differentiation must be made because products exist in physical reality, so always carry some technical features. In contrast, written disclosures may miss technical information and can even be theoretical in some instances.

Comments in relation to the second and third referred questions

If the answer to question 1 is no, is technical information about said product which was made available to the public before the filing date (e.g. by publication of technical brochure, non-patent or patent literature) state of the art within the meaning of Article 54(2) EPC, irrespective of whether the composition or internal structure of the product could be analysed and reproduced without undue burden by the skilled person before that date?

If the answer to question 1 is yes or the answer to question 2 is no, which criteria are to be applied in order to determine whether or not the composition or internal structure of the product could be analysed and reproduced without undue burden within the meaning of opinion G 1/92? In particular, is it required that the composition and internal structure of the product be fully analysable and identically reproducible?

The comments on the second and third questions were much shorter than the first. Borealis argued that the answer to the second question should be yes: technical information in relation to a product made available to the public forms part of the state of the art, irrespective of whether said product could be reproduced in its entirety without undue burden. An answer to the third question was not required. The representatives for the President of the EPO presented similar arguments.

Mitsui argued the answer to the second question should be no, reasoning that any technical information disclosed in relation to a product cannot be separated from the product itself without making a generalisation and therefore artificially broadening a disclosure. Regarding the third question, Mitsui argued that this should be for the relevant Technical Board to decide.

Final remarks

The Board indicated that all relevant issues had been discussed, and that the minutes and decision will be published as soon as possible. No comments or decision was issued following the hearing. We will continue to monitor the referral and will provide an update once the decision has been issued.