The European Patent Office (EPO) in known for taking a strict approach towards literal support to patent claims, and thus restricts amendments that do not literally correspond to wording found in the application as originally filed. However, a recent decision of the EPO’s highest instance – the Enlarged Board of Appeal (decision No. G 1/16, held on December 18, 2017) reveals circumstances under which a disclaimer, which was not present in the original application, can be introduced into the claims.

The decision concerns the allowability of undisclosed disclaimers. An ‘undisclosed disclaimer’ is a negative claim amendment that is not based on any “negative” language in the application as originally filed. It is useful for excluding from the claims embodiment(s) found to be known during examination. In the decision, the Enlarged Board of Appeal has confirmed that undisclosed disclaimers are allowable under certain circumstances, namely in order to:

1. Restore novelty by delimiting a claim against a publication, which was published after the priority date(e.g. a different patent application, which was pre-published at the priority date of the application being prosecuted);
2. Restore novelty by delimiting a claim against an accidental anticipation. An anticipation is accidental if it is unrelated to the claimed invention, such that the skilled person would not consider it when making the invention, and thus the publication cannot be considered for determining inventive step; or
3. Disclaim subject-matter which is excluded from patentability for nontechnical reasons; meaning that the disclaimer must not be related to the teaching of the claimed invention.