Article 123 of the European Patent Convention (EPC) relates to the amendments under the EPC, i.e. the amendments to a European patent application or patent, and notably the conditions under which they are allowable. In particular, prohibits adding subject-matter going beyond the content of the application as filed, while prohibits an extension of the scope of protection by amendment after grant. In addition, limits the types of amendments that can be done during opposition proceedings before the European Patent Office (EPO), and relates to the correction of errors in documents filed with the EPO.
Background
The EPC provides that an applicant may in principle amend the documents constituting their European patent application after filing, as it is considered that the applicant may not have a full picture of the prior art at the time when the application is drafted and filed with the EPO.
Article 123(1) EPC: Procedural framework for amendments
Article 123(1) EPC provides the right for an applicant, in proceedings before the European Patent Office (EPO), to amend its European patent application and for a patent proprietor (during opposition proceedings) the right to amend its European patent. This must however be done in accordance with the Implementing Regulations, considering that the applicant is given "at least one opportunity to amend the application of his own volition." According to the Implementing Regulations, amendments before receiving the (extended) European search report are generally not allowed. Amendments are allowed in response to the extended European search report (i.e., in response to the communication under ) and amendments are also allowed shortly after entry into European phase of a PCT application (namely, in response to the communication under ). Then, any further amendment is subject to the consent of the Examining Division.
Article 123(2) EPC: General substantive requirements for amendments
Overview
Article 123(2) EPC provides that a European patent application, or European patent, may not be amended (both before and after grant) in such a way that it contains subject-matter which extends beyond the content of the application as filed. In other words, an amendment cannot go beyond the original disclosure of the application. The amended subject-matter must be directly and unambiguously derivable (i.e., clearly and unambiguously derivable), for a skilled person, "using common general knowledge, and seen objectively and relative to the date of filing," from the content of the application as filed. "After the amendment the skilled person may not be presented with new technical information." This test is often referred to as the "gold standard" for assessing compliance with Article 123(2) EPC at the EPO. "The underlying idea of Art. 123(2) EPC is that an applicant should not be allowed to improve his position by adding subject-matter not disclosed in the application as filed, which would give him an unwarranted advantage and could be damaging to the legal security of third parties relying on the content of the original application (...)." This legal provision illustrates the importance accorded by the Convention to the content of a European patent application as filed –i.e. on the filing date– in respect of its legal effects.
Article 123(2) EPC does not concern whether amendments have introduced an expression not present in the application as filed, but whether the amendments have introduced subject-matter extending beyond the content of the application as filed. In other words, the only relevant question is whether the skilled person is confronted, in the amended version of the application or the patent, with additional technical information compared to the technical information contained in the application as filed. If so, Article 123(2) EPC is violated.
An extension of the subject-matter of the European patent beyond the content of the application as filed is a ground of opposition, and revocation.
Standard of proof
When assessing the content of a European patent application as filed, the applicable standard of proof is a rigorous standard, namely the certainty "beyond reasonable doubt" rather than the "balance of probabilities", the normal standard of proof in civil proceedings.