3.8.1 Reproducibility

Depending on the circumstance of each case, also a non-reproducible product may be considered to represent the closest prior art or just a source of a complementary technical teaching, suitable for combination with the closest prior art. Thus, disclosed but non-reproducible features of a product may, but need not, flow into the assessment of inventive step (G 1/23, OJ 2025, A68).

The extent to which a non-reproducible product must be modified to obtain the claimed subject-matter, and the level of knowledge about that product and its manufacture required to achieve it, are not considered relevant for determining whether the product can be regarded as the closest prior art. These aspects instead relate to later stages of the problem–solution approach, namely identifying the distinguishing features between the product and the claimed subject-matter and/or assessing whether the skilled person, starting from that product, would have been able to obtain the claimed one (T 1044/23).

In T 1719/21, the board confirmed that the mere fact that a commercially available but non‑reproducible polymer lacked publicly accessible information on its composition or manufacture did not preclude its consideration as a possible starting point. In view of G 1/23, the board found that commercial product ENGAGE® 8400 and all its analysable properties and structure belonged to the state of the art. The product was physically accessible, irrespective of whether or not particular reasons could be identified for analysing its composition and structure, also if the skilled person would not have been in the position to reproduce it on their own (see G 1/23, point 91 of the Reasons). What needs to be modified is part of the inventive thinking of the skilled person in order to solve the problem addressed, not a consideration concerning the selection of that starting point.