The European Patent Office’s Enlarged Board of Appeal recently clarified that a product made publicly available before a patent’s filing date is considered prior art, even if a skilled person has not yet understood or reproduced its exact composition or structure. We examine how this decision may impact approaches to patent filings and discuss why businesses should now exercise greater caution if launching products before their patent applications are filed.
On 1 July 2025, the Enlarged Board of Appeal (EBA) of the European Patent Office (EPO) issued a decision that provides much-needed clarity on whether a publicly – and, specifically, commercially – available product comprises part of the state of the art as according to Article 54(2) of the European Patent Convention (EPC), even if that product’s internal structure or composition has not yet been analysed or reproduced.
This decision is particularly helpful to businesses developing products based on more complex structures, such as polymers.
What was the previous position on publicly available products?
The concept of whether something is ‘publicly available’ is important in patent law. It determines what constitutes prior art and can be used to refuse a patent application, or revoke a granted patent, on the grounds of a lack of novelty or inventive step.
Until recently, EPO case law precedent had established that a commercially available product was not considered publicly available by default, unless it could be analysed and reproduced by someone skilled in the relevant technical area using standard methods that were available at the time.
This position was framed by the decision in G1/92, which broadly determined that a product’s chemical composition would comprise part of the state of the art if the product was available to the public and it could be analysed and reproduced by the skilled person.
This position seems sensible when considered alongside discrete molecular systems, such as pharmaceuticals. In such cases, it is relatively straightforward for a skilled person to reverse-engineer and reproduce the composition and structural properties of a discrete molecular system that has been made commercially available, and therefore difficult for a business to argue that the system is novel or inventive when applying for a patent.
Why is the G1/92 decision problematic?
This position has led to some questionable decisions in which a company is granted patent protection for a product that has been commercially available for several years.
It is particularly problematic for more complex chemical products, such as polymers or compositions comprising hundreds/ thousands of distinct species, such as crude oil.
Polymers, particularly those derived from multiple distinct monomeric species (i.e. copolymers) and those cross-linked in two or three spatial dimensions are inherently difficult to analyse and reproduce, even if they have been publicly available for some time.
Their structural complexity and lack of long-range order, for example, means it is difficult, if not impossible, to analyse them at an atomic level using standard methods, such as crystallography.
Their pronounced sensitivity to experimental parameters, as well as the inherent randomness of polymer formation mechanisms, also make it difficult to reproduce them synthetically, even under seemingly identical reaction conditions.
Nevertheless, if one follows the logic of G1/92, one could argue that products comprising polymers or other complex chemical substances have not been publicly disclosed even after years of being commercially available, simply because they are too difficult to analyse and reproduce.
How did the G1/23 decision come about?
With this in mind, it seems fitting that the case leading to the G1/23 referral at the EBA relates to a complex polymer.
According to the opposition, the patent application lacked inventive step because the commercial product, an ethylene-octene copolymer with properties that were relevant to the patent’s claims, had been publicly available before the patent’s priority date.
Technical documents that predated the patent at issue had also disclosed some of the commercial product’s properties, including density, tensile strength, hardness, and melting temperature.
In its counterargument, the patent’s proprietor relied on the decision in G1/92, stating that it was not straightforward for the skilled person to reproduce the commercial product without undue burden because its manufacturing method had not been publicly available at the priority date. As such, the commercial product did not comprise part of the start of the art.
What questions were referred to the EBA?
Given the complexity of the case law under discussion, the Technical Board for the appeal referred three questions to the EBA:
- Should a product that is put on the market before a European patent application’s filing date be excluded from the state of the art within the meaning of Article 54(2) EPC just because 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 that product’s technical information, which was made available to the public before the filing date, state of the art within the meaning of Article 54(2) EPC, regardless of whether the product’s composition or internal structure 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 should be applied to determine whether the product’s composition or internal structure could be analysed or reproduced without undue burden within the meaning of G1/92? In particular, should the product’s composition and internal structure be fully analysable and identically reproducible?
What was the EBA’s decision?
In its answers to these three questions, the EBA decided that:
- A product that is put on the market before a European patent application’s date of filing cannot be excluded from the state of the art within the meaning of Article 54(2) EPC just because a skilled person could not analyse or reproduce its composition or internal structure before that date.
- Technical information can form part of the state of the art within the meaning of Article 54(2) EPC, regardless of whether the skilled person could analyse and reproduce the product and its composition or internal structure before that date.
- In light of the answers to questions 1 and 2, an answer to question 3 is not required.
What precedent does G1/23 set?
The decision in G1/23 represents a substantial shift away from the precedent set by G1/92, insofar as it affirms that the ability to analyse and produce a publicly (e.g. commercially) available product is inconsequential when considering whether that product comprises part of the state of the art.
Furthermore, technical features that have been analysed and disclosed are similarly deemed to comprise part of the state of the art when examining novelty and inventive step, even if a skilled person cannot reproduce them without undue burden.
By clarifying that a commercial product is considered publicly available simply by virtue of its placement on the market, this decision arguably eliminates a loophole that has allowed patent protection to be sought for products already marketed and sold.
This does mean that businesses now need to exercise greater caution when deciding timings for patent applications and product launches.
In most instances, and as should be the case, it is safer to ensure patent applications are on file before making a product commercially available.
Do it the other way round, and you run the risk that valid patent protection cannot be secured, even if your competitors have yet to uncover your product’s secrets by the time your application is filed.