The Show Must(n't) Go On: G 2/24 Closes The Curtain On Interveners' Rights At The EPO

At the European Patent Office (EPO), third parties may intervene in ongoing opposition or opposition-appeal proceedings relating to a European patent, under certain conditions. But just how far do interveners' rights extend in such proceedings?

The right to intervene is governed by the legal provisions of the European Patent Convention (EPC). According to Article 105 EPC, a third party may intervene in ongoing opposition proceedings if it can be shown that:

• There is a pending infringement action instituted against the third party at the Unified Patent Court (UPC) or a national court, or
• That the third party has requested a court ruling for a declaration of non-infringement.

In the earlier Enlarged Board of Appeal (EBA) decision G 1/94, the provisions of Article 105 EPC were interpreted as extending to allowing interventions at the opposition-appeal stage, even if the third party did not intervene during first instance opposition proceedings. Therefore, a notice of intervention can be filed during either opposition or opposition-appeal proceedings, subject to the condition that the intervention is within three months of the action that justifies its admissibility.

At first instance opposition proceedings, Article 105(2) EPC clearly sets out that an admissible intervention is to be treated as an opposition. This allows the intervener to become a party to the opposition proceedings, thus gaining essentially the same rights as an opponent. For example, the intervener gains the right to raise a new ground of opposition, introduce new prior art documents and accelerate opposition proceedings.

Once opposition proceedings have concluded, the question arises as to what rights an intervener has to appeal the decision. Article 107 EPC provides:

Any party to proceedings adversely affected by a decision may appeal. Any other parties to the proceedings shall be parties to the appeal proceedings as of right.

Under this provision, the intervener (who was a party to the opposition proceedings under Article 105 EPC) has the right to appeal if they have been adversely affected by a decision of the Opposition Division, such as where the intervener requests revocation of the patent but the patent is maintained. That is, the intervener continues to have the same rights as an opponent.

However, the lines are less clear about the status of an intervener who only files an admissible intervention once opposition-appeal proceedings have commenced (as permitted under G 1/94). Under Article 107 EPC, such interveners are not party to the opposition proceedings and are only party to the appeal proceedings 'as of right'. This raises uncertainty about whether the intervener can continue appeal proceedings (and thus acquire appellant status) if the original appellant(s) subsequently withdraws the appeal.

G 2/24 directly addresses this scenario and stems from T 1286/23, which concerns EP 2941163, a patent owned by Foreo AB and directed to an oscillating handheld skin cleanser. In T 1286/23, the opponent (Beurer GmbH) had filed an appeal against the decision of the Opposition Division to maintain the granted patent in amended form. Meanwhile, an alleged infringing third-party (Geske GmbH & Co. KG) had begun proceedings in the German courts seeking a declaration of non-infringement of the patent.

Notably, Geske had twice attempted to intervene at the opposition stage, but the interventions were deemed inadmissible as a result of procedural considerations. On the first intervention, a warning letter from Foreo had been sent to Geske, but no infringement action had actually been instituted. On the second intervention, Geske had sought a declaration of non-infringement, but in the absence of receipt by Foreo at the time of the intervention, German courts could not consider these proceedings to be pending.

Whilst Geske's third intervention was admissible, Beurer (the sole opponent-appellant) subsequently withdrew their appeal before oral proceedings. With Geske as the only remaining party challenging the decision, it was left with the Board of Appeal to determine whether appeal proceedings could continue with only the intervener as the appellant.

This issue has been previously considered in G 3/04, where it was found by the EBA that after withdrawal of the sole appeal, the proceedings may not be continued with a third party who intervened during the appeal proceedings. The Board of Appeal in the present case challenged this precedent, taking the position that the intervener has legal interests extraneous to the EPC (i.e. at national infringement proceedings), and so limiting interveners' rights to assume the status of opponent but not appellant is inequitable.

Since this conclusion led to a departure from the ruling of G 3/04, the following question was referred to the EBA under Article 112(1)(a) EPC:

"After withdrawal of all appeals, may the proceedings be continued with a third party who intervened during the appeal proceedings? In particular, may the third party acquire an appellant status corresponding to the status of a person entitled to appeal within the meaning of Article 107, first sentence, EPC?"

Notably, both the President of the EPO and the Institute of Professional Representatives before the EPO (epi) submitted amicus curiae briefs in support of a revision to the findings of G 3/04.

In G 2/24, the EBA has reiterated the principles of G 3/04 and found the arguments of the referring Board of Appeal and the amicus curiae briefs to be unconvincing. The reasons for the decision emphasise the judicial nature of appeal proceedings in its aim to eliminate 'adverse effects' of the impugned decision, rather than being a continuation of first instance proceedings.

Regarding the status of an appellant, the EBA held that a party entitled to appeal within the meaning of Article 107 EPC is only the person who had formally participated in the proceedings before the department that issued the impugned decision. The EBA also found that no substantive changes had been made to the EPC since G 3/04 was issued, and thus the EPC does not confer full opponent-appellant status to interveners. As a result, intervener's procedural rights remain limited in appeal proceedings, leaving them at the whim of the original appellants, who have the ability to terminate proceedings by withdrawal.

G 2/24 thus reaffirms that an intervener joining an opposition at the appeal stage does not have the right to continue the appeal if the original appellants withdraw the appeal. The intervener, as a mere party as of right in appeal proceedings, does not acquire the status of an independent appellant and the appeal proceedings therefore terminate upon withdrawal of all appeals, with the decision of the Opposition Division being made final.

In an unfavourable outcome for alleged infringers, the EBA has set clear boundaries for interveners by maintaining the status quo of G 3/04, emphasising the importance of filing oppositions early to secure their status as party to first and second instance proceedings. For patent proprietors, G 2/24 underscores the strategic benefits of pursuing settlement agreements in contentious proceedings, as an agreement with an opponent-appellant leading to withdrawal of the appeal will deprive an intervener of an opportunity to continue the appeal.

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