Support of the Description and Art. 84 EPC: Why Reactive Amendments to the Description Harm Legal Certainty.

The article focuses on the interpretation of the description support criterion under Article 84 of the European Patent Convention (EPC) in European Patent Office (EPO) proceedings. It contrasts two main approaches: a narrow interpretation, exemplified by decision T 1024/18, which requires the patent description to be fully consistent with the granted claims and mandates deletion or amendment of any conflicting embodiments; and a broad interpretation, as in decision T 1989/18, which does not require post-grant amendments to the description even if it contains subject-matter not covered by the claims. The narrow approach raises legal challenges including potential violations of Article 123(2) EPC (prohibition of added subject-matter), impacts on infringement assessments under the doctrine of equivalents, and risks of unintended abandonment of subject-matter. The article argues that the broad interpretation better preserves legal certainty and practical feasibility, while the narrow interpretation creates unresolved problems and confusion regarding the role and content of the description in patent documents.