When are nullity proceedings admissible if opposition proceedings are (still) underway at the European Patent Office (EPO)? This question was addressed by the Federal Court of Justice (Bundesgerichtshof – BGH) on December 6, 2022, in its "Aminopyridine" decision (X ZR 47/22). The case concerned a nullity suit which had been filed although opposition appeal proceedings before the EPO were still ongoing. According to the Patent Act (Section 81 (2)), nullity proceedings are not admissible “as long as an opposition can still be filed or opposition proceedings are pending”.
However, the BGH found in its ruling that it is not the formal conclusion of the opposition proceedings that is relevant for the admissibility of the suit, but rather that the proceedings must have reached a stage “in which the risk of contradictory decisions or of unnecessarily dealing with a matter twice no longer exists”.
The ruling is very important for nullity claimants in practice: “It may make sense, for example, to file a nullity suit with the Federal Patent Court (Bundespatentgericht) immediately after the oral hearing in opposition appeal proceedings if the final version of the patent claim has already been determined at that time and thus there is no longer anything standing in the way of filing an action,” says Dr. Viktoria Lindemann, patent attorney trainee at Cohausz & Florack.
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