In referral G1/23, the Enlarged Board of Appeal is expected to clarify under which conditions a product available on the market, and partial information about its composition, published before the filing or priority date of a European patent application, are state of the art within the meaning of Article 54(2) of the European Patent Convention, and particularly to what extent – if any – enablement plays a role; European Patent Attorneys Sofia Santoro and Alessandra Antonucci summarise the facts and the importance of the case.

With interlocutory decision T0438/19, the Technical Board of Appeal of the European Patent Office (EPO) has referred the following three questions to the Enlarged Board of Appeal (referral pending under G1/23 “solar cell”): 

 “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 (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?

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 G1/92? In particular, is it required that the composition and internal structure of the product be fully analysable and identically reproducible?”

The Enlarged Board of Appeal is therefore expected to clarify under which conditions a product available on the market and (partial) information about its composition published before the filing (or priority) date of a European patent application are state of the art within the meaning of Article 54(2) EPC.

Background of the case

 The Appeal lies against the Opposition Division’s decision to maintain European patent No. 2626911 as granted i.e. with its main claim referring to a material suitable for encapsulating solar cells comprising an ethylene/α-olefin copolymer having certain properties, such as density and hardness, and a specific aluminium content.

The Opposition Division concluded that the claimed material was inventive over a prior art document disclosing a commercially available copolymer (ENGAGE^® 8400) having all the feature of claim 1 except for a lower aluminium content because a skilled person – knowing that the encapsulating composition has better properties when the aluminium content is low – would have reduced it rather than increased it up to the claimed amount.

The patent proprietor’s argument according to which the prior art document was not enabling – raised for the first time at the oral proceedings – was not dealt with by the Opposition Division.

Contrary to that, the Board of Appeal is of the opinion that ENGAGE^® 8400 – if acknowledged as part of the state of the art – is likely to prejudice inventive step of claim 1 as granted, also on account of a prior document newly admitted into the appeal proceedings which teaches a level of aluminium overlapping with the claimed range. Therefore, in the Board’s view, a decision as to whether the subject-matter of granted claim 1 involves an inventive step ultimately depends on the question of whether the (commercially available) product ENGAGE^® 8400 has been made available to the public before the effective date of the patent within the meaning of Article 54(2) EPC.

In this regard, the patent proprietor – relying upon point 1.4 of the Reasons for opinion G1/92 – reiterates that the document disclosing ENGAGE^® 8400 is not enabling and therefore does not form part of the state of the art since the skilled person would have not been able to exactly reproduce the copolymer disclosed therein without undue burden.

The Appellant instead maintains that it would be unreasonable to disregard publicly available information for the sole reason that the specific commercial product could not be exactly reproduced (i.e. just in some but not in all its properties).

The selection of the closest prior art hence appears to depend on the interpretation of G1/92 for which, however, divergent Case Law exists.

Article 54(2) EPC and G1/92 under the lens of the Board of Appeal

According to Art. 54(2) EPC, an invention is novel if it does not form part of the state of the art, the latter being held to comprise “everything made available to the public” before the filing (or priority) date of the patent application.

Moreover, opinion G1/92 concerns the interpretation of the requirement “made available to the public” referred to in Article 54(2) EPC in relation to the prior use of a product, and postulates that:

“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.”

In this regard, the Board notes that, concordantly with G1/92, decisions T206/83 and T26/85 both convey the rationale that a disclosure which is not enabling is not comprised in the state of the art defined in Article 54(2) EPC. However, going back to the Travaux Préparatoires to the EPC, it would appear that the expression “available to the public” in Article 54(2) EPC was originally meant to express the mere accessibility to the public of the prior art without any requirement as to its enablement.

The Board also emphasises that diverging Case Law on application of G1/92 exists, specifically about (i) the interpretation of “available to the public” leading to the exclusion from the state of the art of the product itself or just of its chemical composition/internal structure, a criterion that can have a huge impact on the selection of the closest prior art as well as about (ii) full analysability and (iii) exact reproducibility of the product, criteria that in the Board’s view could lead to a subjective evaluation of what does or does not fall within the state of the art.

Finally, the Board makes reference to decision of the High Court of England and Wales TAKEDA UK LTD v F. HOFFMANN-LA ROCHE AG [2019] EWHC 1911 (sections 119 to 135) in which the Court considered the “full reproducibility” approach – requiring that for a marketed product to be state of the art the skilled person would have to be in the position to prepare the product as such, in all its properties (i.e. not only those specified in the claimed subject-matter) – as going beyond the spirit of G1/92.

Comment

It comes as no surprise that the above issue has been raised in connection with polymers for which, as expressly noted by the Board, there is no recognised definition of what would constitute a “comprehensive analysis”. Nevertheless, the G1/23 opinion could have a significant impact on all cases concerning prior use or an even wider impact if the Enlarged Board of Appeal will decide that enablement shouldn’t play any role in deciding whether a prior art is to be considered as made available to the public or not, as originally provided for in the Travaux Préparatoires.