It is a long-established principle in EPO practice that the description of a patent must not include statements that are inconsistent with the claims. Thus, under Article 84 of the European Patent Convention (EPC), the EPO requires that applicants and patent proprietors adapt the description to reflect amendments to the claims. The requested description changes are typically made at the end of examination or opposition proceedings. The EPO appeal decisions that have established that practice are sometimes jointly referred to as a “first line of case law” pertaining to Article 84 of the EPC.
However, some recent decisions of the Technical Boards of Appeal suggest that neither Article 84 of the EPC nor any other EPC provisions provide a proper legal basis for mandatory amendments to the description in the event that the claims are amended. Those decisions are often referred to as a “second line of case law”.
In decision T 697/22 of July 29 2025, a Technical Board of Appeal of the EPO concluded that an opposition appeal could not be finally decided, even though a set of amended claims filed by the patent proprietor was held to comply with all applicable legal provisions. However, an adequately adapted version of the description had not been filed in due time by the patent proprietor, and hence the patent could not be maintained under the first line of case law. If the second line of case law was applied, the patent could be upheld on the basis of the allowed claims and a version of the description including statements that are inconsistent with the claims.
The matter was hence referred to the Enlarged Board of Appeal, which is to clarify if, and in view of which provisions, the EPO can insist on mandatory description amendments. While the submissions of both parties to the proceedings, as well as the majority of amicus curiae briefs, favour the second line of case law – i.e., the abandonment of established EPO practice – some amicus briefs, as well as the president of the EPO, have argued in favour of the first line of case law.
The oral proceedings before the EPO on May 8 will be attended by the parties and the EPO president, and will be livestreamed. A decision on the matter is expected this year.
