d) Products put on the market and their analysable properties 

In many cases the ability to recognise a technical teaching such as the internal structure or composition of a product in prior use presupposes analysis of the product embodying this technical teaching. What exactly about a product that is available on the open market is considered as disclosed to the public is an issue that the boards have considered on a number of occasions.

(i) Product 

In G 1/23 (OJ 2025, A68), the Enlarged Board clarified that 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 Art. 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 expression "product put on the market" in this context is to be understood as covering both man-made and naturally occurring products.

(ii) Internal structure or composition 

In T 952/92 (OJ 1995, 755) the board stated that information as to the composition or internal structure of a prior sold product is made available to the public and becomes part of the state of the art if direct and unambiguous access to such information is possible by means of known analytical techniques which were available for use by a skilled person before the relevant filing date (see also T 2/09). The board also stated that the likelihood or otherwise of a skilled person analysing such a prior sold product, and the degree of burden (i.e. the amount of work and time involved in carrying out such an analysis), is in principle irrelevant to the determination of what constitutes the state of the art. The novelty of a claimed invention is destroyed by the prior disclosure (by any means) of an embodiment which falls within the claim. The possibility of a complete analysis of a prior sold product is not necessary. The novelty of a claim is destroyed if an analysis of a prior sold product is such as to inform the skilled person of an embodiment of the product which falls within the claim.

In G 1/92 (OJ 1993, 277) the Enlarged Board held that the chemical composition of a product forms part of the 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 same principle applies mutatis mutandis to any other product. It also stated that "[a]n 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 to 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".

In G 1/23 the Enlarged Board explained that the contradictions of an enablement requirement set up by G 1/92 disappear if the condition of reproducibility in the answer of G 1/92 can be interpreted as including the obtaining of the product from the market in its readily available form. Put differently, the expected reproducibility of the product is to be understood in a broader sense, namely as the ability of the skilled person to obtain and possess the physical product. This meant that the requirement would be inherently fulfilled by a product put on the market. This, in turn, led to the conclusion that the condition is in fact redundant. Thus, the answer of the opinion G 1/92 could not be maintained in its entirety.

The Enlarged Board held that the proper reading of the answer of G 1/92 is as follows: 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. It also followed from the correct interpretation of G 1/92 that all analysable properties of the product put on the market belong to the state of the art, i.e. they represent technical information that the skilled person is aware of and will consider relying on when looking at technical solutions.

To answer the referred questions, the Enlarged Board in G 1/23 did not need to determine at which point the efforts of the skilled person to analyse the marketed product would reach the threshold of "undue burden", or whether this is a condition at all.

At the time of writing, only a few decisions have applied G 1/23. In T 807/23 the board recognised that in application of G 1/23, it was clear that the reproducibility requirement is no longer a valid criterion to assess whether a product put on the market before the date of filing of the opposed patent or technical information about such a product is state of the art within the meaning of Art. 54(2) EPC (see also T 1044/23, T 141/24 and T 143/24).

The following decisions predate G 1/23. They are nevertheless included here because analysis of a product disclosed prior to the relevant priority date was at issue.

In T 390/88 a photographic film had been made available to the public by announcement at a press conference three weeks before the priority date. The board held that this relatively short time interval was sufficient to enable interested parties to become fully aware of the film's composition.

In T 461/88 (OJ 1993, 295) the board ruled that a control program stored on a microchip had not been made available to the public if the analysis of the program would require an expenditure of effort on a scale which could only be reckoned in man-years and if, for economic reasons, it was highly improbable that the sole purchaser of the machine controlled by the program had carried out such an analysis (see obiter dictum in T 969/90, see also T 212/99).

In T 969/90 and T 953/90 the board ruled that the internal structure of a product in prior use had been made available to the public because a skilled person relying on the normal means of investigation available to them would have been able to analyse the product.

In T 2048/12 the board stated that opinion G 1/92 did not imply that in each and every case the commercial availability of a chemical product as such necessarily amounted to a disclosure of (also) all the impurities contained therein merely because it was possible to identify and quantify these impurities by analytical means. Conclusion 1 of G 1/92 was to be read by attributing a technically reasonable meaning to the technical expression "chemical composition". In the present case there was no direct or indirect pointer to the possible technical relevance of further impurities (besides water) in the commercial product.

In T 2068/15, the board considered in the case at issue that the skilled person analysing the film with the techniques known at that time (electron microscopy) would not have overlooked the first top layer. And the board stated also that it was common practice at the priority date of the patent to apply more than one analytical method in order to obtain information about the composition of a material.

In T 1452/16 (alleged prior use of Amano lactase) the board stated that in order to assess whether a prior-art product falls within the terms of the claim, one obviously has to assess the claimed parameters, even if these have never been used before. Furthermore, the board explained in detail why the present cases differed from T 946/04, T 1457/09, T 2048/12 and T 2068/15. Contrary to the patent proprietor's arguments, the board noted firstly that T 952/92 did not stipulate that structural assays had to be used, and second that the skilled person did not have to test for all possible impurities. The board came to the conclusion that the evidence on file convincingly demonstrated that a lactase preparation fulfilling the parameters (given ratio) recited in claim 1 of the main request was publicly available, that an enzyme with the characteristics as claimed was commercially available in the prior art and that its use in a process as claimed had also been made available to a member of the public, and hence was state of the art. See also T 1540/21.

(iii) Technical information 

In G 1/23, the Enlarged Board explained that technical information about a product put on the market before the date of filing of a European patent application which was made available to the public before the filing date forms part of the state of the art within the meaning of Art. 54(2) EPC, irrespective of whether the skilled person could analyse and reproduce the product and its composition or internal structure before that date.

(iv) Extrinsic characteristics 

In G 1/92  the Enlarged Board held that "a commercially available product per se does not implicitly disclose anything beyond its composition or internal structure. Extrinsic characteristics, which are only revealed when the product is exposed to interaction with specifically chosen outside conditions, e.g., reactants or the like, in order to provide a particular effect or result or to discover potential results or capabilities, therefore point beyond the product per se as they are dependent on deliberate choices being made. Typical examples are the application as a pharmaceutical product of a known substance or composition (see Article 54(5) EPC) and the use of a known compound for a particular purpose, based on a new technical effect (see G 2/88, OJ 1990, 93). Thus, such characteristics cannot be considered as already having been made available to the public".

In T 472/92 (OJ 1998, 161) the board referred to G 1/92 and concluded that the printability characteristic of the material was not a property that became available to the public by their mere delivery, since this was clearly an extrinsic characteristic requiring interaction with specifically chosen outside conditions. Thus, such characteristic could not be considered as already having been made available to the public (see also T 267/92).

In T 1409/16 the board decided that commercial composition only accessible by subjecting said prior art composition to a kind of reverse engineering (by fractionation) based on hindsight revealed "extrinsic characteristic" within the meaning of G 1/92 (see also similar case T 834/15).

In T 1666/16 (powders – angle of repose), the board could not conclude that the skilled person was able to determine the internal structure of the sold products and to reproduce them without undue burden at the date of their sale; the internal structure of these products did not form part of the prior art. The issue of extrinsic characteristics in view of G 1/92 was also at stake.