04/07/2025
The Enlarged Board of Appeal has issued their decision on referral G1/23. As set out in the headnote, the decision states that:
- A product put on the market before the date of filing of a European patent application cannot 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 by the skilled person before that date.
- Technical information about such a product which was made available to the public before the filing date forms part of the state of the art within the meaning of Article 54(2) EPC, irrespective of whether the skilled person could analyse and reproduce the product and its composition or internal structure before that date.
The decision provides a welcome and long-awaited clarification that, when a product is made publicly available, the product becomes prior art even if the skilled person is unable to reverse-engineer and reproduce the product. The decision and its background are explored in more detail below.
Background
The G1/23 referral came from a Technical Board of Appeal for an opposition-appeal on European patent EP2626911 (EP’911), relating to an encapsulating material for a solar cell. A key issue of the appeal related to whether a publicly available polymer, the “ENGAGE® 8400” polymer, could be considered prior art.
The ENGAGE® 8400 polymer is a complex polymer with properties relevant to the claims of the patent. The polymer was commercially available before the date of the patent, and certain properties of the polymer were demonstrated by various pieces of technical documentation. However, the method for manufacturing the ENGAGE® 8400 polymer was not in the public domain, and it was agreed by the parties to the appeal that reproduction of the polymer would not have been straightforward, even if the polymer were available to the skilled person for analysis.
In view of this, the patent proprietor and opponent disagreed on whether the ENGAGE® 8400 polymer should be considered prior art for the purposes of Article 54(2) EPC, taking into account the rationale of the Enlarged Board in an earlier decision, G1/92: “The chemical composition of a product is considered to be part of the state of the art if the product itself is available to the public and can be analysed and reproduced by a person skilled in the art, irrespective of whether there are particular reasons for analysing the composition”.
Although the ENGAGE® 8400 polymer was commercially available before the priority date of the patent, did the fact that it was not straightforward to reproduce exactly mean that it failed to meet the requirement that prior art provide an enabling or reproducible disclosure? And how did the availability of the various pieces of technical documentation before the priority date of the patent affect the situation?
The opponent argued that the polymer should be considered prior art irrespective of the reproducibility of the polymer, and that the properties of the polymer disclosed in the technical documentation were relevant and should not be disregarded merely because the polymer could not be reproduced. In contrast, the patent proprietor argued that the polymer should not be considered prior art because of its lack of reproducibility, and that since the polymer did not form part of the state of the art, neither could the technical documentation.
Decision G1/92 and subsequent diverging case law
The earlier decision, G1/92, states that “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” (emphasis added).
It seems that this statement led to diverging case law. In particular, where it was not possible for the skilled person “to discover the composition or the internal structure of the product and to reproduce it without undue burden”, some Technical Boards of Appeal considered only the product’s composition or internal structure excluded from the prior art (such as in decisions T 370/02, T 2045/09, T 0023/11, and T 1833/14), but others considered both the product itself and its composition or internal structure excluded from the prior art (such as in decisions T 946/04 and T 1666/16).
The above divergence in case law led the Technical Board for the appeal on EP’911 to refer three questions to the Enlarged Board.
Referred questions
The three questions referred to the Enlarged Board were:
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?
G1/23 decision
The G1/23 decision states that:
- The answer to question 1 is no. As such, a product put on the market before the date of filing of a European patent application cannot 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 by the skilled person before that date.
- The answer to question 2 is yes. As such, technical information about such a product which was made available to the public before the filing date forms part of the state of the art within the meaning of Article 54(2) EPC, irrespective of whether the skilled person could analyse and reproduce the product and its composition or internal structure before that date.
- The answers to questions 1 and 2 render question 3 moot.
The decision clarifies that the reference to the reproducibility of a product in G1/92 must be understood in a broad sense, namely as the ability of the skilled person to obtain and possess the product. This includes the ability of the skilled person to obtain the product from the market.
Conclusion
The decision of the Enlarged Board in G1/23 provides welcome legal clarity. The decision confirms that public availability, not technical reproducibility, is the key for determining what is prior art, and thus confirms that a publicly available product cannot be excluded as prior art for the sole reason that the product’s composition or internal structure could not be reproduced by the skilled person.
The decision therefore prevents the peculiar situation where a company manufactures and sells a product for many years but is later able to obtain patent protection for that product because the company kept the method of making the product secret and the skilled person is unable to reverse-engineer and reproduce the product. In this sense, G1/23 has effectively confirmed the existence of an “on-sale bar” provision for patentability at the EPO. This would seem to simplify and better align the law on prior art disclosures at the EPO with the practical realities of innovation in complex material technologies.
This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking any action in reliance on it.
