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Reproducibility as a prerequisite under Article 54(2) EPC – Decision of the Enlarged Board of Appeal of the EPO dated 2 July 2025 – G 1/23
On 2 July 2025, the Enlarged Board of Appeal of the European Patent Office (Enlarged Board) handed down its long-awaited decision in case G 1/23.
The case concerned the question of the extent to which a publicly available product must be reproducible by a person skilled in the art in order to be considered prior art under Art. 54(2) EPC.
I. Facts and issue
The subject of the opposition proceedings was a patent protecting the technical teaching for encapsulating solar cells. The opponent considered a commercially available polymer to be prejudicial to novelty. It was undisputed between the parties that the exact manufacturing process was not generally known. The opponent therefore argued that a person skilled in the art would be able to produce a polymer similar to the available product. However, exact reproducibility could not be legally required. While the Opposition Division rejected the opposition, the Board of Appeal referred the following three questions to the Enlarged Board of Appeal:
- 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?
- 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?
II. Considerations of the Enlarged Board of Appeal
In this context, the Enlarged Board of Appeal once again dealt in depth with a decision from 1992 (G 1/92). In that case, the Enlarged Board of Appeal had ruled 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.”
The Enlarged Board of Appeal noted that the question referred for the G 1/92 decision did not contain any reference to reproducibility of any kind. It read as follows:
Is the chemical composition of a product made available to the public by virtue of the availability to the public of that product, irrespective of whether particular reasons can be identified to cause the skilled person to analyse the composition?
The Enlarged Board of Appeal therefore first examined the question of whether the feature of reproducibility should be assessed differently depending on whether the reproducibility of the chemical composition or of the entire product was considered. However, the Enlarged Board of Appeal concluded that the requirement of reproducibility was no longer tenable in either interpretation.
The criterion of reproducibility created a legal fiction according to which a product that was actually freely available did not exist for the skilled person. This contradicted general life experience. Furthermore, exceptions must be handled restrictively and standardised by law. In the present case, it was not apparent from the law why public products should be treated differently from written prior art, which – unlike patent applications – is also not examined for its feasibility.
In addition, the requirement of reproducibility would mean that the precursors of the product potentially damaging to novelty would also have to be reproducible, since the skilled person could also only use the prior art to assess the question of reproducibility. This would mean that the skilled person would not only have to be very familiar with the vertical distribution chain, but would ultimately also have to be able to reproduce all preliminary products, i.e., in extreme cases, starting at the atomic and molecular level. The Enlarged Board of Appeal referred, by way of example, to crude oil, which is the precursor to countless applications and yet cannot be reproduced to this day. This example shows that the requirement of reproducibility leads to inappropriate results.
The Enlarged Board of Appeal emphasised that, although it is theoretically possible to draw a line in the distribution chain, this cannot lead to satisfactory results given the multitude of technical areas.
Therefore, the requirement of reproducibility must be dropped.
As this already eliminated the second part of the cumulative requirement of the question referred (“analysed and reproduced without undue burden”), it was no longer relevant whether the undue burden requirement also applied to analysability. The Enlarged Board of Appeal suggested that there could well be cases in which analysability constituted an unreasonable burden, but left open the question of whether this had any bearing on whether a product belonged to the state of the art or not.
III. Answers to the questions referred
The Enlarged Board of Appeal subsequently answered the first question referred (in the negative) as follows:
“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 Enlarged Board of Appeal answered the second question referred for a preliminary ruling with a logical “yes” and explained:
“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.”
Since the third question referred required either a yes answer to the first question or a no answer to the second question, the Enlarged Board of Appeal left it open.
IV. Assessment
The skilled person no longer needs to be able to reproduce a product for it to be considered prior art. Analysability is sufficient. This increases legal certainty for third parties. The requirements are identical for all technical fields and independent of the details of the specific case. The Enlarged Board of Appeal has thus opted for an all-or-nothing solution in order to avoid contradictions. This is successful. On the other hand, the decision severely restricts the position of patent holders in opposition and appeal proceedings. The future will show whether a more differentiated approach is necessary after all.
National courts have so far predominantly pursued a more restrictive approach, as also pointed out by the AIPPI in its amicus curiae brief.
In the European context, it remains to be seen what course the Court of Appeal of the Unified Patent Court will take, which in the past has been open to EPO case law, as this naturally provides a more harmonised European approach than decisions by national courts.