EPO Board confirms public prior use based on confidential analysis

In T1324/21, the EPO Boards of Appeal addressed the role of internal evidence in proving public prior use. The case related to claims to a pharmaceutical composition containing specific polymorphic forms of rifaximin. 

The opponents raised a novelty objection based on the public prior use of Xifaxan tablets available on the market before the priority date. A key piece of evidence was a declaration presenting internal analyses that described the exact composition of the prior use product based on internal production records. 

In the first instance, the Opposition Division excluded this piece of evidence, reasoning that the analysis was internal and confidential, and thus not part of the state of the art. However, the Board of Appeal reversed this decision, emphasizing a crucial point: while the analysis itself was confidential, it merely confirmed the composition of the product that was publicly available before the priority date. 

The Board's reasoning drew on G 1/92, which establishes that the composition of a publicly available product becomes part of the state of the art if it can be analyzed and reproduced by a skilled person. The internal nature of the evidence did not undermine its relevance in proving that the public had access to a tablet falling within the scope of the claimed composition before the priority date. 

Ultimately, the Board revoked the patent based on this finding. This decision highlights the importance of well-documented evidence in proving prior use and demonstrates that such evidence, can play an important role in opposition and appeal proceedings, even if found in internal documents which are not prior art.  

Thorsten Bausch and Arianna Bartolini co-represented one of the opponents together with Dr. Inge Hiebl from Kraus and Lederer in this case.