In UPC_CFI_523/2025, Wittenstein SE v Vestas Wind Systems A/S, the Court of First Instance, Central Division (Section Munich), decided on 2 September 2026 how lack of entitlement may operate as a ground for revocation under Article 138(1)(e) EPC. The Court held that it is not sufficient for a claimant to establish rights to only part of the patented subject-matter: revocation on this ground requires proof that the registered proprietor has no rights to the patent.
Background
The case concerned European patent with unitary effect EP 4 226 039, relating to a wind-turbine power transmission system using radially movable tooth segments. Wittenstein sought revocation on several grounds, including lack of novelty, lack of inventive step, insufficiency and lack of entitlement. It argued that Vestas was neither the inventor nor the inventor’s successor in title and that an employee of Wittenstein had made the invention, or at least a significant contribution to it. The parties had previously cooperated on the development of the relevant gearbox technology.
The entitlement dispute arose under Article 138(1)(e) EPC, which permits revocation where the proprietor is not entitled to the patent under Article 60(1) EPC.
Entitlement as a revocation ground
The Court first distinguished a revocation action based on lack of entitlement from proceedings determining who has the better right to the patent (para. 150). It noted that there are differing views on whether Article 138(1)(e) EPC may be invoked only by the inventor or successor in title, or also by unrelated third parties. The Court did not resolve that question. Wittenstein had presented facts and evidence making its own claimed entitlement, at least as successor to a possible co-inventor, not prima facie implausible. That was sufficient for it to rely on Article 138(1)(e) EPC in these proceedings (paras. 151–153).
The Court then addressed what must be proved for the revocation ground to succeed. It interpreted the requirement that the proprietor “is not entitled” as requiring the proprietor to have no rights to the patent. Demonstrating that the claimant has rights to part of the patented subject-matter, for example through the contribution of a co-inventor, is insufficient (para. 154).
This conclusion was combined with the rebuttable presumption under Rule 8.5(c) RoP that the person recorded in the European Patent Register is entitled to be registered as proprietor. The burden of presenting and proving facts establishing lack of entitlement therefore remained with Wittenstein (paras. 155–156).
Application and implications
On the evidence, Wittenstein did not establish that its alleged inventor was the sole inventor. The Court considered his account of his contribution insufficiently detailed, while the documentary evidence did not show that Vestas had made no contribution. The evidence instead pointed to Vestas’ registered inventor being at least a co-inventor. It therefore had not been shown that Vestas lacked any rights to the patent, and the entitlement attack failed (paras. 157–162).
The decision illustrates the distinction between establishing a contribution to an invention and proving lack of entitlement for the purposes of Article 138(1)(e) EPC. Where joint development is involved, evidence supporting co-inventorship alone will not establish this revocation ground if the registered proprietor retains rights through another inventor.
The patent was nevertheless revoked as to dependent claims 21 and 22 for insufficiency and maintained in amended form with those claims deleted.
