G1/23 - Commercially available products are prior art even if not reproducible

The Enlarged Board of Appeal of the European Patent Office (EPO) issued its decision yesterday in G1/23, providing long awaited clarification on whether a commercially available product, whose internal structure cannot be analysed or reproduced, forms part of the state of the art under Article 54(2) EPC.

In a significant departure from G1/92, the Board held that a product placed on the market before the filing date cannot be excluded from the state of the art for the sole reason that its composition or internal structure cannot be analysed and reproduced by the skilled person without undue burden.

Case Background: T0438/19 and ENGAGE ® 8400

This referral came from an appeal case T0438/19 involving patent EP2626911 which concerned a polymer for solar cell encapsulation. The opponent had brought an inventive step attack on the basis of a prior art document which disclosed a similar encapsulating polymer material (called “ENGAGE 8400”). The patent proprietor argued that, since there was not sufficient public information on how to make the polymer, it did not constitute prior art, arguing that under the Enlarged Board’s previous case law G 1/92, only analysable and reproducible products qualify as prior art.

For more information on the background to the case, make sure you check out our previous article on this referral from March 2025.

The Decision in G1/23

The Enlarged Board has answered the referred questions as follows:

I. 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.

II. 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.

This decision marks a clear departure from earlier interpretations of G 1/92, which had introduced an "enablement" test for products made available by prior use. The Board has rejected this approach, describing it as a legal fiction inconsistent with the EPC. Instead, it held that public availability alone is sufficient: if a product was commercially available, it forms part of the state of the art, regardless of whether the skilled person could analyse and reproduce it.

Here at Abel + Imray we will be reviewing the decision in detail and considering its implications for filing strategies, freedom-to-operate assessments, and opposition practice. We’ll be publishing a future article exploring the practical consequences of this decision for our clients. Make sure you keep up to date with our future updates by following us on LinkedIn.

If you have any immediate questions about how this might affect your pending or future applications or would like to discuss the impact of G 1/23 for your portfolio or filing strategy, please contact Chris Lindsay, Katy Pellow, or your usual Abel + Imray advisor.