European Patent Office Clarifies When Patent Descriptions Must Be Amended to Match Claims

John Richards, Of Counsel at Ladas & Parry LLP’s New York Office, has published a new article examining the Enlarged Board of Appeal of the European Patent Office’s decision in Case G1/25, issued September 3, 2026. The decision addresses a question of longstanding practical importance to patent applicants and owners: when must the description of a European patent application or patent be amended to conform to claims that were changed during examination or opposition proceedings? 

Building on the Enlarged Board’s earlier decision in G1/2024 and the Unified Patent Court’s ruling in NanoString Technologies v. 10x Genomics, the Board held that description amendments are required only where an inconsistency between the claims and description creates genuine doubt as to the meaning of a claim or otherwise causes the application or patent to fail to meet a requirement of the European Patent Convention. The decision carries practical implications for the scope, cost, and strategy of European patent prosecution. 

Read the full article in our Education Center here.