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G1/16 – Enlarged Board of Appeal decision on allowability of undisclosed disclaimers

Under the European patent practice, it is sometimes possible for claims to define the claimed subject-matter by explicitly excluding some features from the claimed invention. Such excluded claim features are referred to as “disclaimers.” Disclaimers are classified into two categories – disclosed disclaimers and undisclosed disclaimers. Under Article 123(2) EPC, amendments must not add new subject matter beyond the scope of an application as originally filed. However, an earlier Enlarged Board of Appeal decision, G1/03, stated that undisclosed disclaimers (not originally disclosed in the application as filed) could be used in a limited set of circumstances. In a later decision, G2/10, the Enlarged Board ruled that disclaimers had to conform to the “gold” standard for assessing added matter. It was held that the subject matter remaining in the claim after the introduction of the disclaimer had to be directly and unambiguously derivable from the application as originally filed by a skilled person in the light of his common general knowledge.

The Enlarged Board of Appeal recently issued decision G1/16, which provides clarity regarding the allowability of undisclosed disclaimers in view of seemingly conflicting decisions G1/03 and G2/10. The Enlarged Board emphasised that there is a fundamental distinction between undisclosed disclaimers and disclosed disclaimers in terms of their legal nature. This necessitates providing for each of the two classes of disclaimers a single specific test for assessing whether the introduction of a disclaimer complies with Article 123(2) EPC. The Board thus decided that the test for discloseddisclaimers is the “gold” standard test of G2/10, and the assessment of the allowability of a claim amendment by an undiscloseddisclaimer is governed exclusively by the criteria laid down in G1/03. This decision has settled this apparent conflict by clarifying that the “gold” standard does not apply to “undisclosed” disclaimers that meet the requirements of G1/03. In accordance with that, for an undisclosed disclaimer to be allowable, its purpose must be to overcome objections relating to:

  1. novelty-only prior art under Article 54(3) EPC,
  2. accidental novelty disclosures, or
  3. excluded subject matter (e.g. non-technical features).

The board further clarified that the disclaimer must not go beyond what is necessary to overcome the objections and must not introduce clarity issues. It must also not be relevant for assessing inventive step or sufficiency of disclosure.

As standard practice, disclaimers should be used with caution. If an objection can be overcome with a usual amendment, then that should be relied upon instead of disclaimers. Also, practitioners and patent holders should be prepared with a back-up plan if the disclaimer is subsequently found to add matter.

If you have any questions on this topic, please contact Andy Cloughley at


Article written by Prajwal Nirwan

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