Abstract This article explores the legal institution of prior user rights in the context of the Unified Patent Court (UPC) and its interplay with national laws. It examines Art. 28 of the UPC Agreement, which defers the regulation of prior user rights to domestic legal frameworks, and analyses how this decentralised model influences both the substantive and procedural dimensions of protection. Through a comparative analysis of selected jurisdictions – Germany, France, the United Kingdom and the United States – the article identifies key similarities and divergences in legal treatment. Particular attention is given to the evidentiary standards, legal scope, and limitations attached to the prior user right. Drawing on these insights, the article proposes a set of common denominators that could guide the UPC toward a more consistent and coherent approach, despite the lack of harmonisation. Ultimately, it highlights the potential of prior user protection to serve as a fair and functional counterbalance within a patent system based on first-to-file principles.
Marta Sznajder (Wed,) studied this question.