A patent claim needs to be novel and comprise an inventive step in view of what was public "prior art" before the filing date (or priority date) of the patent application. Therefore, the "prior art" sets a key yardstick for whether or not a patent claim is valid.
In the recent landmark decision G 1/23, the Enlarged Board of Appeal (EBA) of the European Patent Office (EPO) addressed under what conditions a product put on the market qualifies as prior art under Article 54(2) EPC.
This major decision overhauls the standard set more than three decades ago by the EBA in decision G 1/92.
1. General principles set out by G 1/92
Previously, G 1/92 had set out a test for the "availability to the public". It found that the chemical composition of a product is state of the art when the following three criteria are met:
- the product as such is available to the public and
- can be analyzed by the skilled person (irrespective of the difficulty of the analysis) and
- can be reproduced by the skilled person without undue burden, irrespective of whether particular reasons can be identified for analyzing the composition.
That generally meant that, if a product is on the market, but it cannot be reproduced by the skilled person "without undue burden", the product could still be patented later on (if the patent application describes the details on how to reproduce it).
2. Case underlying G 1/23
The appeal proceedings concerned the decision of the Opposition Division rejecting the opposition against European patent EP 2 626 911. Claim 1 is directed at a material that is suitable for encapsulating a solar cell and comprises a specific polymer defined by its chemical composition including the aluminum content and its physical properties.
In the referring decision, the Board determined that the assessment of inventive step for the subject matter of claim 1 depends on whether the product ENGAGE® 8400 was "made available to the public" within the meaning of Article 54(2) EPC. While the product was publicly available, its exact composition and manufacturing process were not disclosed, raising questions about whether it could be considered part of the prior art under Article 54(2) EPC. In particular, the question arose to which extent the product's commercial availability resulted in it being "made available to the public" in light of G 1/92.
The Referring Board referred three legal questions to the EBA, focusing on whether reproducibility is a prerequisite for a product to qualify as prior art:
Question 1
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 analyzed and reproduced without undue burden by the skilled person before that date?
Question 2
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 a 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 analyzed and reproduced without undue burden by the skilled person before that date?
Question 3
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 analyzed and reproduced without undue burden within the meaning of opinion G 1/92? In particular, is it required that the composition and internal structure of the product be fully analyzable and identically reproducible?
3. Decision G 1/23
The EBA answered Questions 1 and 2 as follows:
- A product put on the market cannot be excluded from the state
of the art solely because its composition or internal structure
could not be analyzed and reproduced by a skilled person before the
filing date.
- Publicly available technical information about such a product forms part of the state of the art, regardless of whether the product or its composition could be analyzed and reproduced.
The third referred question, concerning criteria for determining reproducibility, was deemed moot in light of the answers to the first two questions.
4. Practical advice
a. Rethinking prior art
The EBA explicitly stated that any product put on the market is made available to the public and thus forms part of the prior art. As the condition of reproducibility is defined in the broadest possible way as obtaining and possessing the physical product, the overall extent of prior art is increased significantly including any product that has ever been on the market anywhere in the world. The prior art under Article 54(2) EPC also encompasses all technical teachings derivable from a product put on the market, regardless of whether the product or its composition could be reproduced and even if the product later disappears or is modified.
This may present new challenges for patent proprietors as marketed products become more relevant as prior art, and new possibilities arise for opponents to challenge both novelty and inventive step.
Importantly, the decision only relates to physical products. It does not question or change the accepted concept that information made available via other means, like written or oral disclosure, must be such that the skilled person can reproduce that subject matter. The same holds true for methods and uses, including therapeutic uses and the disclosure requirements previously established in this context.
b. The practical legal problem of proof
In its decision, the EBA distinguished between the legal status of a product as prior art and the practical challenges of proving its properties. As the EBA also questioned whether the concept of "undue burden" for the analysis of the marketed product is a valid condition at all and omitted it from the answers, arguments based on "undue burden" may fall short in the future. Reconstructing the properties still remains a matter of evidence and proof, or as the EBA put it, "a practical legal problem of proof for the lawyer" (Reasons 84). Discussions about the relevance of a marketed product will shift from the question of whether a product belongs to the prior art because it is non-reproducible to the question of whether the chemical composition and the physical properties of the product can be proven.
c. Inventive step
While the inability to reproduce certain features may affect the relevance of the product for inventive step, it does not exclude the product or its properties from the prior art. The decision also reaffirmed that disclosed but non-reproducible features of a product may influence the assessment of inventive step, depending on the specific case (Reasons 96). However, the relevance of such features is context-dependent and must be evaluated in light of both the product and the invention.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
