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G1/23: The Enlarged Board of Appeal shift EPO practice towards an “on-sale” bar.
September 2025
Last week, the EPO’s Enlarged Board of Appeal (EBA) issued its Decision that both a product put on the market before the date of filing of a European patent application, and technical information related thereto but also available before said date, should not be excluded from the prior art for the sole reason that its composition or internal structure could not be analysed and reproduced by the skilled person before that date. Indeed, the EBA have affirmed, by being placed on the market, a product may be “reproduced” simply through repeat purchase. Thus, by lowering the bar for acts constituting reproduction, the EBA have effectively shifted EPO practice towards an “on-sale” exclusion to patentability which appears similar to that applied by the USPTO.
Background
EP2626911 was granted with an independent claim directed towards an encapsulating material for a solar cell comprising an ethylene/α-olefin copolymer having a variety of properties including a content of aluminium element of from 10 to 500 ppm.
During Opposition proceedings, the Patent was opposed on the grounds of inventive step based on a disclosure of a commercially available “ENGAGE 8400” polymer (disclosed in D1) that met all of the requirements of Claim 1 (as evidenced by technical data sheets provided during proceedings) except for the content of aluminium, which was only 4.4 ppm.
The Patentee, during the Opposition Oral Proceedings, argued that D1 should be excluded from the state of the art under Article 54(2) EPC in line with the decision of G1/92. The Opposition Division did not comment specifically on this oral argument of the Patentee in their decision. However, Claim 1 was found to be inventive over D1 implying that the Opposition Division did consider D1 to form part of the state of the art.
The Appeal (T0438/19)
The Patentee, for the first time in writing, re-ran the same argument over D1 citing r 1.4 of G1/92 as support which reads:
“1.4 An essential purpose of any technical teaching is to enable the person skilled in the art to manufacture or use a given product by applying such teaching. Where such teaching results from a product put on the market, the person skilled in the art will have to rely on his general technical knowledge to gather all information enabling him to prepare the said product. Where it is possible for the skilled person 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)
The Patentee argument was that because the skilled person would be unable to prepare ENGAGE 8400 (i.e. the product) without undue burden (because its composition or internal structure is not known) both the product and its composition should be excluded from the prior art, in spite of the products’ commercial availability.
In other words, the Patentee effectively argued that r 1.4 of G1/92 inherently leads to the inverse conclusion that where it is not possible for the skilled person to discover the composition or internal structure of a product and to reproduce the product without undue burden, then both the product and its composition or internal structure do not become state of the art.
In its referring Decision, the Board of Appeal noted that G1/92 appeared to be widely considered to introduce an enablement requirement for a product to be considered to be prior art. Yet, the Board also noted that such a requirement was at odds with the genesis of the novelty provision (Article 54 EPC) and what the term “available to the public” was intended to express with respect to the prior art, as exemplified by the relevant passages of the Travaux Préparatoires to the EPC (see paragraph 10-10.5 of the referring decision).
The Board of Appeal further noted that there was significant divergence in the case law stemming from G1/92. In a first line of case law, the composition or internal structure was handled separately from the product such that an available product itself forms part of the prior art but its composition is excluded when the skilled person is unable reproduce the composition (e.g. T946/04, T1666/16). The second line of case law states that the inability to produce the composition necessarily excluded both the composition and the product from the prior art (e.g. T370/02, T2045/02, T1833/14, T23/11).
As a result of the divergence, the Board referred the following questions to the Enlarged Board of Appeal for clarification of the law:
- 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 G1/92? In particular, is it required that the composition and internal structure of the product be fully analysable and identically reproducible?
The Decision of the Enlarged Board
The Enlarged Board acknowledge that G1/92 only appears to make sense when reproducibility is understood to mean that the skilled person is able to make the product by the same or a different route (see paragraphs 37 and 38). Yet the Enlarged Board found that such an interpretation could not be followed.
Throughout the decision, the Enlarged Board stressed that every man-made pre-cursor or material can ultimately be reduced back to a starting compound that itself could not be made by the skilled person using the common general knowledge and so, following the logical conclusion, would not be enabled. Thus, if it is found that an irreproducible pre-cursor does not form part of the state of the art, any product stemming from that precursor would also need to be removed, resulting in all products on earth being eliminated eventually (if you go back far enough in the production chain) (See paragraph 60). The Enlarged Board considered such a finding to be “clearly absurd”.
The Enlarged Board also makes note of the Patentee’s admission that naturally occurring chemicals are “obviously reproducible” but considers the argument to be flawed as the skilled person is not themself “making” the product but rather “obtaining” or “taking” it from nature. The skilled person, therefore, does not possess the skills to manufacture the natural product, indeed many natural products are nearly impossible to replicate synthetically (e.g. crude oil, see paragraphs 61 and 62).
The Enlarged Board determined that there was no difference between purchasing a commercially available starting product from a manufacturer and taking a naturally occurring product from nature. Indeed, the Enlarged Board emphatically determined that interpreting the term “reproduce” to mean “to make” or “produce” is far too narrow a construction. Instead, a product should be considered to be “reproducible” if it can be purchased or obtained repeatedly with consistent properties. Accordingly, a commercially-available product is, by its very nature, reproducible and relied on as such by chemists during their ordinary working practices (ee paragraphs 2.4.2.).
With respect to the composition or internal structure, the Enlarged Board acknowledged that there is a prima facie interpretation, which is not unreasonable, that a composition may be excluded from the state of the art, even if the product itself is included, because a skilled person could use a known product (e.g. for its physical properties) without knowing its composition. Yet, once again, the Enlarged Board considered such an interpretation to be unsustainable, returning again to the reasoning that, if you go far enough back in the production of any chemical, an irreproducible product will inevitably be found, forcing the skilled person to deal with a non-reproducible composition.
The Enlarged Board concluded that excluding a composition from the prior art that may itself be known (or discoverable by techniques known at the date of filing) solely on the basis that it cannot itself be produced (e.g. because it comes from nature) would be manifestly unfair and fly in the face of the normal behaviour of the skilled person who would routinely purchase starting materials from manufacturers in the real world (see section 2.4.3.). Such an interpretation that excludes the composition (but retains the product) based on G1/92 therefore could not be followed.
Correct Interpretation of G1/92
The Enlarged Board rejected both interpretations of G1/92 presented by the referring Board of Appeal, instead finding that a broader interpretation of reproducibility must be applied and that “the answer of the opinion [of] G1/92 cannot be maintained in its entirety” (paragraph 74). The Enlarged Board therefore appears to have determined that there is no enablement requirement for a product placed on the market to be part of the prior art, moving patentability before the EPO somewhat closer to the USPTO’s “on-sale” exclusion.
Moreover, it found that the correct reading of G1/92 is:
“The chemical composition of a product is part of the state of the art when the product as such is available to the public and can be analysed by the skilled person, irrespective of whether or not particular reasons can be identified for analysing the composition” (paragraph 73).
Decision
The referred questions were answered as follows:
- No
- Yes
- Rendered moot by answers 1 and 2.
Commentary
Firstly, it is important to note that the Enlarged Board did not determine that an irreproducible product may form part of the state of the art. Instead, they merely broadened the interpretation of “reproducibility” to include the purchase of a substantially identical product.
Secondly, when considering the decision it appears worthwhile contemplating the consequences had the Enlarged Board followed G1/92. Possibly, this would have allowed manufacturers to sell their products without risking the patentability of a later filed Patent (as long as the product could not be remade by the skilled person), providing an artificial extension to the patenting life of their products.
When considering this outcome, the Enlarged Board’s decision appears to be rooted in what they consider to be the most equitable and manifestly fair interpretation of patentability based on G1/92 for all parties. Indeed, the Enlarged Boards shift towards an “on-sale” requirement all but eliminates the possibility for excluding products or disclosures relating thereto from the prior art based on their enablement, or lack thereof.
Thirdly, this decision may give practitioners greater assurance that, when drafting European patent applications, a reference to a commercially available component may be sufficient to provide an enabling disclosure of that component. Accordingly, a full description of how that component is produced no longer appears necessary to demonstrate reproducibility of that component.
This article was written by Patent Attorney Alexandra Tyson
