In May 2024, we were successful with a complete revocation of the European patent EP 2 651442 B2 before the Boards of Appeal of the European Patent Office. This removes a major obstacle in the field of switchable chimeric antigen receptor (CAR) T cells.

The revocation was mainly based on formalities:

• clarity of post-grant amendments to claims,
• added subject matter, and
• priority of features (partial priority) and lack of inventive step with respect to an intermediate publication.

One of the key issues was that there were only single dependent claims in the PCT application, and in the European patent granted, claim 1 was a combination of the subject matter of the original filed claim 1 and several dependent claims. As there was no back-reference between the dependent claims (and no basis in the description for the combination), the combination of the subject matter of these claims was considered as not to have been originally disclosed and was therefore found to add matter. This decision shows once again that the provision of a basis for the combination of features and/or embodiments in the description is essential for European patent applications.