In a recent decision by the EPO’s Boards of Appeal, T 437/14, three questions have been referred to the Enlarged Board of Appeal concerning the allowability of undisclosed disclaimers. The decision concerns an appeal filed against the decision of the opposition division to maintain EP1933395, which relates to phosphorescent organometallic compounds, in amended form.

During the opposition proceedings, the patent proprietors, the University of Southern California and the Trustees of Princeton University, had filed a number of claim requests. Some of these requests introduced ‘undisclosed disclaimers’ into the claims, in an attempt to overcome prior art documents which were considered to be ‘accidental anticipations’. In the end, the claims on which the opposition division decided to maintain the patent did not contain any undisclosed disclaimers. However, in the appeal proceedings, the proprietors requested that the patent be maintained on the basis of previous claim requests filed during the opposition, which included undisclosed disclaimers. In order to decide on these requests, the Board considered that further questions regarding the allowability of undisclosed disclaimers needed to be addressed, and therefore decided to refer questions to the Enlarged Board of Appeal.

An undisclosed disclaimer is a disclaimer (ie a ‘negative’ claim feature excluding subject matter from the scope of protection of a claim) which has no basis in the application as filed. The allowability of undisclosed disclaimers has previously been considered by the Enlarged Board of Appeal in decisions G 1/03 and G 2/03, and according to answer 2.1 of G 1/03, an undisclosed disclaimer is allowable in order to:

  • restore novelty over a document cited under Article 54(3) (novelty-only citation);
  • restore novelty over an accidental anticipation; an anticipation is accidental if it is so unrelated to and remote from the claimed invention that the person skilled in the art would never have taken it into consideration when making the invention; or
  • disclaim subject matter which is excluded from patentability for non-technical reasons (e.g. methods of treatment).

In a subsequent decision, G 2/10, the Enlarged Board of Appeal established that, when determining the allowability of disclosed disclaimers under Article 123(2) EPC,

The test to be applied is whether the skilled person would, using common general knowledge, regard the remaining claimed subject-matter as explicitly or implicitly, but directly and unambiguously, disclosed in the application as filed" (second paragraph of point 4.5.4 of the reasons in G 2/10).

Whilst the question referred to in G 2/10 concerned disclosed disclaimers, the Board in T 437/14 considered that the conclusion to be drawn from G 2/10 appears to be that the above test is the “gold standard” for assessing any amendment for compliance with Article 123(2) EPC. Furthermore, the Board noted that, if the gold standard is the only test that should be applied for assessing the allowability of amendments (Article 123(2) EPC), then this would appear to leave no room for the exceptions relating to undisclosed disclaimers defined in answer 2.1 of G 1/03.

In light of this, the Board in T 437/14 concluded that further clarification is required regarding the assessment of undisclosed disclaimers, and has therefore referred the following questions to the Enlarged Board of Appeal:

  1. Is the standard referred to in G 2/10 for the allowability of disclosed disclaimers under Article 123(2) EPC, ie whether the skilled person would, using common general knowledge, regard the subject matter remaining in the claim after the introduction of the disclaimer as explicitly or implicitly, but directly and unambiguously, disclosed in the application as filed, also to be applied to claims containing undisclosed disclaimers?
  2. If the answer to the first question is yes, is G 1/03 set aside as regards the exceptions relating to undisclosed disclaimers defined in its answer 2.1?
  3. If the answer to the second question is no, ie if the exceptions relating to undisclosed disclaimers defined in answer 2.1 of G 1/03 apply in addition to the standard referred to in G 2/10, may this standard be modified in view of these exceptions?

So what could these questions mean in practice? In the view of the Board in T 437/14, most undisclosed disclaimers would be unallowable if the gold standard of G 2/10 is to be applied in respect of all amendments (ie including the introduction of undisclosed disclaimers). However, it may be that the Enlarged Board of Appeal can agree on an interpretation of G 2/10 which is compatible with the principles set out in G 1/03 and G 2/03, such that these principles can continue to apply.