Time waits for no one: interveners race the clock in accelerated EPO appeals

In a significant decision issued in December 2024, the European Patent Office (EPO) Technical Board of Appeal has provided important guidance on the handling of late interventions during accelerated appeal proceedings.

The case (T 1841/23) involved a European patent owned by Koninklijke KPN N.V. and directed to managing associated network sessions. During appeal proceedings, an intervention was filed shortly before scheduled oral proceedings, leading to fundamental questions about procedural rights and timing.

Background

The case centred on an appeal against an Opposition Division’s decision to maintain the opposed patent in amended form. Following information from the Unified Patent Court (UPC) about parallel infringement proceedings, the Board accelerated the appeal proceedings and adopted a strict procedural framework.

A notice of intervention was filed just weeks before the scheduled oral proceedings. This led to requests from the patent proprietor for postponement, citing insufficient time to respond and concerns about the right to be heard under Article 113(1) EPC.

Key findings and practical implications

The Board made several significant determinations that provide important guidance for European patent attorneys and their clients:

1. Late interventions do not automatically justify postponements. The Board held that an admissible intervention filed shortly before oral proceedings does not generally excuse the proprietor or other parties, and does not automatically entitle them to more time.
2. Case-by-case assessment is required. The implications of a late intervention should be determined based on specific circumstances, considering both the EPC and Rules of Procedure of the Boards of Appeal.
3. Opposition proceedings are not tactical tools. The Board emphasised that opposition appeal proceedings are not designed to serve as placeholders for tactical considerations in parallel infringement proceedings. They represent an existential challenge to the patent itself.

The decision provides clear guidance that late interventions will not automatically delay proceedings, particularly in accelerated cases. Patent proprietors should be prepared to handle interventions within existing procedural timeframes.

The Board’s emphasis on avoiding tactical use of procedures also suggests increased scrutiny of postponement requests that appear driven by parallel litigation strategy rather than genuine procedural needs.

A broader picture of intervention practice

This decision has come at a particularly significant time, as the EPO continues to grapple with fundamental questions about intervention rights and procedures. As we recently reported, the Enlarged Board of Appeal is currently considering in G 2/24 whether an intervener can continue proceedings after all appeals are withdrawn. While G 2/24 examines the extent of intervener rights, T 1841/23 addresses the constraints within which those rights must be exercised.

Together, these decisions reflect the EPO’s ongoing effort to strike a delicate balance. Where G 2/24 may potentially expand intervener rights (with the Board questioning the restrictive approach of G 3/04), T 1841/23 makes clear that such rights must be exercised within strict procedural boundaries. The message seems clear: while the EPO may be open to reconsidering the scope of intervention rights, it remains committed to procedural efficiency and will not allow intervention practices to delay proceedings unduly or serve as tactical tools in parallel litigation.

These developments in intervention practice could have significant implications for patent strategy, particularly given the increasing interplay between EPO proceedings and UPC litigation. While G 2/24 may reshape the fundamental rights of interveners after appeal withdrawal, T 1841/23 makes clear that procedural efficiency will not be compromised regardless of how those rights are ultimately defined. Patent proprietors and potential opponents will need to consider carefully both the timing and forum of their actions.

Looking ahead

This decision reflects the EPO’s continued focus on procedural efficiency while balancing parties’ rights. When considered alongside other recent decisions like G 2/24 on intervener status after appeal withdrawal, it suggests the Boards are actively refining intervention practice to ensure both fairness and efficiency.

For more information about the implications of this decision, please contact your usual GJE attorney or email us at gje@gje.com.