There has been a new referral to the Enlarged Board of Appeal (EBA). This first referral of 2023 seeks clarification on the enablement test for prior use of a product. The referral particularly asks whether the non-enabling prior use of a product excludes the composition of the product from the prior art or whether it also excludes the product per se (i.e. so that it can not be used as a starting point for inventive step). The referral also seeks clarification over the definition of enablement with respect to the prior use of a product, and particularly whether “enablement” requires that the skilled person be able to fully analyse and reproduce the exact same product.
Legal background
The EPC defines the prior art with respect to a claimed invention as “everything made available to the public by means of a written or oral description, by use, or in any other way, before the date of filing of the European patent application” (Article 54(2) EPC). According to existing case law, in order to constitute prior art, a disclosure must also be enabled (EPO Guidelines for Examination, G-IV, 2). Further, according to the established case law from the EBA, if the invention is a product, prior disclosures of the product are only considered to have been “made available to the public” if a skilled person would have been able to analyse and reproduce the product, using common general knowledge (CGK) (G 1/92, headnote).
Details of the referring case: Polymers for solar panels (T 0438/19)
The recent referral arises from the appeal case T 0438/19, relating to the Opposition Division decision to maintain the Mitsui Chemical patent EP 2626911 as granted. The patent relates to polymers for coating and protecting solar cells in solar panels. Claim 1 as granted claims a material for encapsulating a solar cell, comprising various materials such as ethylene and aluminium in specified amounts and densities.
The inventive step of the claimed invention depended on whether prior use of the product ENGAGE 8400 polymer should be considered prior art. It was uncontested that ENGAGE 8400 was commercially available to the public prior to the priority date of the patent. The Opponent submitted data showing that ENGAGE 8400 was a polymer satisfying all the limitations of claim 1 of the granted patent, except for the specified aluminium content. Altering the aluminium content was considered by the Board of Appeal to constitute an obvious modification.
The Patentee argued that the sale of ENGAGE 8400 before the priority date did not constitute an enabling disclosure of the polymer’s composition. Particularly, the Patentee argued that it would be an undue burden for the skilled person to reverse engineer ENGAGE 8400 and then to select the specific catalysts and reaction conditions necessary for manufacture of the product.
Diverging Board of Appeal interpretations of G 1/92 and Article 54(2) EPC
In G 1/92, the EBA concluded that the composition of a product is to be considered “made available to the public” when the product has been made available to the public and can be analysed and reproduced by the skilled person (Headnote). For 30 years, Boards of Appeal have mostly interpreted G 1/92 as requiring three criteria in order for a commercially availability of a product to be considered prior art with respect to a claimed invention: 1) a member of the public must be able to access the product; 2) the skilled person must be able analyse the composition or internal structure of the product; and 3) the skilled person must be able to reproduce the product using CGK without undue burden.
However, the Board of Appeal in the present case found no justification for the “enabling” requirement of “made available to the public” in the intention of the legislator, as evidenced by the historical documentation related to the genesis of Article 54(2) EPC (r. 10.3).
The Board of Appeal also pointed to a potentially confusing paragraph in G 1/92, in which the EBA appeared to suggest that there was a difference between the requirement of the disclosure of a product per se, and the disclosure of the composition of the product:
“An essential purpose of any technical teaching is to enable the person skilled in the art to manufacture or use a given product by applying such teaching. Where such teaching results from a product put on the market, the person skilled in the art will have to rely on his general technical knowledge to gather all information enabling him to prepare the said product. Where it is possible for the skilled person to discover the composition or the internal structure of the product and to reproduce it without undue burden, then both the product and its composition or internal structure become state of the art.”
(G 1/92, r. 1.4, emphasis added)
The Board of Appeal in the present referring case identified divergence in how Boards of Appeal have interpreted G 1/92 in view of this paragraph. Particularly, the referring Board pointed to diverging decisions over how G 1/92 should be applied in cases where a product that was publicly available before the priority date of a patent could not be analysed or reproduced by a skilled person. According to one body of case law, in such a case, only the internal composition of the product should be excluded from the prior art (T 370/02, T 2045/09, T 1833/14, and T 0023/11). According to another body of case law both the product per se and its internal composition should be excluded from the prior art (T 946/04, T 1666/16).
The referring Board argued that the distinction over whether the composition of the product, or both the product and its composition, should be excluded from the prior art is not just a theoretical question, but has practical consequences for inventive step analysis. If a product per se is excluded from the prior art it cannot then be used as a starting point for inventive step in combination with other prior art documents, e.g. documents about the product that may assist in overcoming the enablement issues. Importantly, the enablement test permits the skilled person to use common general knowledge but not prior art documents that do not form part of the CGK.
The referring Board of Appeal also identified diverging decisions on the appropriate criteria for assessing the ability of a skilled person to analyse and reproduce the disclosed product, particularly over the level of analysis required and the degree of variability permitted in reproduction (as discussed in Takeda v Roche [2019] EWHC 1911).
The Board of Appeal concluded by referring the following questions to the EBA (emphasis added):
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 G 1/92? In particular, is it required that the composition and internal structure of the product be fully analysable and identically reproducible?
Final thoughts
The Board of Appeal in the referring decision believes it has identified a divergence in the case law on prior use with practical consequences for inventive step. As specifically noted in the headnote of G 1/92, the issue of enablement in prior use is relevant to all types of products, not just chemical compositions. The outcome of the referral, if accepted as admissible by the EBA, may therefore have consequences across the technical fields.
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This post is based on a previous article on IPKat.
