EPO Practice - Priority Pitfalls In European Patent Applications Based On U.S. Priority Applications

Article 87 of the European Patent Convention (EPC) allows applicants for European patent applications to claim the benefit of the filing date ("priority date") of an earlier application ("priority application") under certain conditions.  While Article 87 EPC broadly corresponds to Article 4 of the Paris Convention, the European Patent Office's (EPO) implementation of Article 87 EPC can lead to denial of priority claims and, ultimately, loss of applicant's rights.  Without careful attention by practitioners, claiming the benefit of a U.S. priority application may result in loss of rights. 

The EPO Enlarged Board of Appeal (EBA) specifically considered the interpretation of Article 87 EPC in its decision G2/98.  The following key points arise when claiming priority under Article 87 EPC: