Added Matter and Article 123(2) EPC -
What is the Test for Claim Broadening?

The EPO is extremely strict when it comes to amendments to a patent application (or indeed a patent) that might add subject matter contrary to Article 123(2). See the article in our Summer 2008 edition of Patent issues “What’s going on at the EPO?”* To those unfamiliar with the rule, the Office appears particularly inflexible when it comes to broadening the scope of the originally filed claims. Contrary to practice in the USPTO, for example, a claim is considered to be prima facie a statement of the essential elements of the invention, so removal of a feature from a claim potentially presents the person skilled in the art with the new information that the omitted feature is not essential. Guideline C-VI, 5.3.10 sets out a three-part test for permitting removal of a feature from a claim, asking certain questions about the extent to which a feature to be removed is “essential”. The book Case Law of the Boards of Appeal of the EPO published by the EPO reviews this test and concludes that the over-riding question is whether the proposed amendments were directly and unambiguously derivable from the application as filed (mentioning in particular Decisions T1206/01 and T731/03). This puts the test of Guideline C-VI, 5.3.10 somewhat in doubt. Is it still valid and appropriate?

According to the Enlarged Board of Appeal (Decision G1/93), the underlying questions to be answered are whether a broadening amendment (a) would give the applicant an unwarranted advantage and (b) could be damaging to the legal certainty of third parties relying on the content of the original application. The “unwarranted advantage” principle may count against an attempt to broaden a claim to account for a later appreciation of a wider applicability for the invention. In view of the “legal certainty” principle, certain boards of appeal have set a rigorous standard of proof under Articles 123(2).

In Decision T383/88, Board 3.3.1 required a standard of proof equivalent to beyond reasonable doubt. But that decision got off on the wrong foot, because it referenced a rigorous standard of proof in an earlier decision T113/86 that related to Article 123(3) – broadening of the claims of a patent after grant. We believe Decision T383/88 was wrong to apply such a rigorous standard of proof. There may be good reason why the standard of proof for Article 123(3) should be higher than the mere balance of probabilities. Once a patent is granted, there is a more acute need for third party certainty. However, during pendency of an application, third parties must inevitably suffer some degree of doubt as to the ultimate scope of the claims. The Board in T383/88 applied a higher standard to Article 123(2) without considering the differences between the two articles.

Decisions T113/86, T383/88 and T581/91 all concerned replacement of a term with an inconsistent term (such as replacement of “1 to 5 kg of A per kg of B” with “1 to 5 kg of B per kg of A” or replacement of “1%” with “0.1%”). What is the test when one considers simply removing a term from a claim? Does the deletion present the person skilled in the art with new information, viz. that the feature is not essential to the invention? In discussion with one of the chairmen of the Boards of Appeal, we are told that some boards prefer only to discuss the term “essential” in the context of features that confer novelty and inventive step. When considering omission of other features, the question to be asked is “whether the skilled person would have understood that the omitted term was optional – i.e. that it added no technical meaning”. This is not necessarily very helpful to applicants. It is more-or-less in line with the directly and unambiguously derivable standard. Any word or phrase that has a technical meaning, however unrelated to the inventive concept, will be viewed with suspicion if an applicant seeks to remove it.

As to the level of proof required, we are optimistic that Decision T383/88 and the later decisions concerning Article 123(2) that follow it will be seen to stand on very uncertain basis. A standard of “not the slightest doubt” may be applicable for amendment under Article 123(3) after grant, but as far as amendments to an application are concerned, those cases include pronouncements on the standard of proof beyond what was necessary to decide upon their facts. They should not be taken into account when considering the intrinsic content of a patent application. Nevertheless, the question whether “the balance of probabilities” or “clear and convincing evidence” or even “beyond reasonable doubt” is the right standard of proof may again arise if an applicant attempts to adduce extrinsic evidence to show what a person of ordinary skill in the art would have read as implicit in a patent application.