In its decision in case G 1/23, the Enlarged Board of Appeal of the European Patent Office has delivered a decisive interpretation of Article 54(2) EPC, removing reproducibility as a condition for a product to constitute prior art.

On 2 July 2025, the Enlarged Board of Appeal (EBoA) of the European Patent Office issued its decision in case G 1/23, bringing clarity to a long-standing question: Can a product that has been put on the market, but whose composition cannot be fully analyzed or reproduced, constitute prior art under Article 54(2) EPC?

This referral, stemming from decision T438/19, addressed a conflicting interpretation of the earlier opinion G 1/92, stating that a product’s composition is part of the state of the art when the product is available to the public and can be both analysed and reproduced by the skilled person (enablement requirement). Some decisions (e.g. T 1833/14, T 0023/11) interpreted G 1/92 narrowly, excluding non-reproducible products from the state of the art. Others (e.g. T 946/04, T 1666/16) acknowledged the product as prior art but excluded internal structural features that could not be derived.

In G 1/23, the EBoA resolved that conflict and held that reproducibility is not a requirement for prior art status under Article 54(2) of the European Patent Convention (EPC) — a product becomes prior art when made publicly available, regardless of whether it can be reproduced from scratch.

Interpreting “Reproducibility”: A Broader Approach

The EBoA first considered the narrow reading of “reproduce” – meaning that the skilled person must be able to manufacture a product anew from starting materials- as problematic: Many products — especially those derived from natural or proprietary sources — cannot realistically be reproduced, even though they are widely available Such an approach would lead to a “manifestly absurd result” (Reasons 60-62) creating a legal fiction detached from real-word commercial and scientific practice.

Instead, the EBoA adopted a broader interpretation: reproducibility includes the ability to obtain or possess the marketed product. In this sense, any product put on the market is inherently reproducible – at least in terms of accessibility – and should be considered publicly available under Article 54(2) EPC. Therefore, a product’s composition is part of the state of the art when the product as such is publicly available before the filing date and can be analysed by the skilled person.

Key holdings of the Decision

Building on such reasoning, the EBoA ruled that a product put on the market before the filing date of a patent application cannot be excluded from the state of the art solely because its composition or internal structure could not be analysed and reproduced by the skilled person (Headnote 1) and that technical information about such product made publicly available (e.g. brochures, datasheets, scientific publications) before the filing date also forms part of the state of the art (Headnote 2).

The third question referred — concerning the criteria for analysability and reproducibility — was deemed moot and left unanswered, as the Board found that the issue of reproducibility no longer required resolution under the revised framework.

Further Observations

In addition to its central findings, the EBoA provided several important clarifications:

• • Disappearance or modification of marketed products – a product’s legal status as prior art is not affected by its later withdrawal from the market or modification. Whilst this may complicate proving particular features in litigation, the abstract technical teaching derivable from the originally marketed product remains permanently part of the state of the art.
  • Novelty vs inventive step – For novelty, it is sufficient that a product was made publicly available; the skilled person’s motivation to analyse it is irrelevant. For inventive step, however, what matters is the technical teaching that would realistically be derived by the skilled person from the product. If certain features cannot be analyzed or reproduced they may be disregarded, making the analysis highly context-dependent.
  • ”Undue burden” for analysis – while G 1/92 had referred to analysability and reproducibility as a combined condition, G 1/23 rejects the need for reproducibility. As for whether analysis must be possible without undue burden, the Board – based on the response given to questions 1 and 2 – considered it unnecessary to address this point but acknowledged that the issue may arise in future proceedings.

Practical implications

• • The G 1/23 decision brings clarity and predictability, with important consequences for both patent applicants and opponents: Commercialized products are prior art the moment they are placed on the market, regardless of whether their composition or internal structure is reproducible.
  • Public disclosures, such as datasheets and related technical materials, also become state of the art if published before the filing date.
  • Early filing is critical – even if reverse engineering is difficult or impossible, patent applications should be filed before any public release or sale of a product, as public availability alone is sufficient to establish prior art.
  • Trade secret strategies may require reconsideration: once a product is sold, patent protection may no longer be possible, even if the underlying process remains secret.

Conclusions

With G 1/23, the Enlarged Board of Appeal has delivered a decisive interpretation of Article 54(2) EPC, removing reproducibility as a condition for a product to constitute prior art.  The focus is now back on the central question of public availability and on what the skilled person can analyse and understand.

This ruling provides greater legal certainty for both patentees and third parties, aligning patent law more closely with commercial and scientific realities. However, it leaves one important question for future clarification: must a marketed product be analysable without undue burden to qualify as prior art in all respects?

Thanks to Sofia Santoro and Olubukola Olumuyiwa for contributing this news item.

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