To what extent does enablement play a role in assessing whether commercially available products are state of the art?

This case relates to an appeal, T 438/19, filed against the decision of the Opposition Division to reject an opposition against EP2626911. In order to determine whether the subject matter of granted claim 1 involved an inventive step in this case, it was necessary to establish whether the commercial product (a polymer sold under the trade mark ENGAGE® 8400) had been made available to the public before the effective filing date of the patent, and could thus represent the closest prior art.

During proceedings before the Technical Board of Appeal, reference was made to the previous Enlarged Board of Appeal’s decision G 1/92, which addressed the requirements for “availability to the public” in the sense of Article 54(2) EPC. In particular, reference was made to the headnote of this opinion, which reads:

1. "The chemical composition of a product is state of the art when the product as such is available to the public and can be analysed and reproduced by the skilled person, irrespective of whether or not particular reasons can be identified for analysing the composition.
2. The same principle applies mutatis mutandis to any other product.”

A particular focus was placed on the degree of analysability and reproducibility required for the ENGAGE® 8400 product to be considered state of the art. This is because in G 1/92 the Enlarged Board of Appeal ruled that the skilled person must be able to discover the composition or internal structure of the product, and then reproduce it without undue burden, for the composition or internal structure to become state of the art.

In its submissions, the opponent argued that an exact reproduction of the product was not required. Moreover, it was argued that irrespective of the extent to which the chemical composition of ENGAGE® 8400 polymer could be reproduced, certain properties of that material (which were covered by the claims) had been placed in the public domain before the filing date, and it would be incorrect and unreasonable to disregard such information on the basis that ENGAGE® 8400 could not be exactly reproduced.

Conversely, the proprietor suggested that while it is not disputed that ENGAGE® 8400 was commercially available before the filing date, the polymer could not have been made available to the public within the meaning of G 1/92, since the skilled person would be unable to exactly reproduce it, and without undue burden. The proprietor indicated that reverse engineering such a polymer, without knowing the conditions for its synthesis, would require an extensive research programme, the need for which would represent an undue burden, and without a guarantee of success.

The proprietor therefore considered that the ENGAGE® 8400 polymer was not enabled and thus could not constitute prior art.

In its analysis, the referring board noted that opinion G 1/92 has given rise to diverging interpretations, leading to legal uncertainty regarding when commercially available products are considered state of the art. For example, the board highlighted diverging interpretations relating to the degree of analysis required to determine the composition of a commercial product, and thus its application as state of the art. Whilst some boards adopted a requirement for the analysis of the exact composition of the product, other boards have adopted a more lenient position, and considered that a complete analysis of a product put on the market was not required to take away the novelty of claimed subject matter. The diverging interpretations arising from G 1/92 are clear from an analysis of T 946/04, where it was suggested that a complete analysis of the product was required, and T 952/92, where a complete analysis was not required.

Similar diverging interpretations have also been provided for the so-called “reproducibility criterion” arising from G 1/92. In particular, while some boards have suggested that G 1/92 indicates that a product must be exactly reproduced, other boards have adopted a more lenient position and considered that a product put on the market constituted prior art without explicitly or only partially addressing its reproducibility. The diverging interpretations arising from G 1/92 in this regard are clear from an analysis of T 977/93, where exact reproduction of the product was required, and T 952/92, where a complete analysis to enable exact reproduction was not required.

In addition, the board highlighted diverging case law regarding whether, when undue burden is found to be required to analyse and reproduce a product, the product and its composition should be excluded from the state of the art, or whether only the composition of the product should be excluded. In order to highlight the importance of this distinction, the board noted the wider implications for inventive step, with emphasis on determining the closest prior art. In particular, if in application of opinion G 1/92 a product is not state of the art pursuant to Article 54(2) EPC, that product cannot be used as starting point for assessing inventive step. However, if the conclusion is only that its composition is not state of the art, but the product itself is still state of the art as it is commercially available, the product could be used as a starting point for the assessment of inventive step, should technical information about that product reported in documents of the state of the art make it of particular interest for the skilled person. The board noted that this was the case in the present appeal, as the commercial product ENGAGE® 8400 was shown in the examples of D1 to be suitable for the same purpose as the present invention.

In view of the above uncertainty, and to ensure uniform application of the law, the following questions have been referred to the Enlarged Board of Appeal:

1. "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.
2. 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 (for example, 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?
3. 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?"

Request for written statements

The Enlarged Board of Appeal is likely to hold oral proceedings in 2024, and its decision may be expected in early 2025. In the meantime, the EPO has provided the opportunity for third parties to file written statements on this matter. Any such submissions are to be filed by 30 November 2023 to ensure that they can be given due consideration. We are monitoring the progress of the case before the Enlarged Board of Appeal and will keep you updated.