G1/25: EBA to decide on hydroponic case between Knauf and Rockwool

The Enlarged Board of Appeal faces its first referral of 2025. The EPO's highest instance must now decide on the office's current legal practice regarding description amendments. The case concerns the grant of a Knauf Insulation patent for a plant growth medium, which Rockwool aims to prevent.

Must the description of a European patent align with amended patent claims? The EPO’s Enlarged Board of Appeal must now address this question. At the end of July, Technical Board of Appeal 3.3.02 under chairman O. Müller referred several questions to the EPO’s highest judicial instance in the dispute between Rockwool and Knauf Insulation (case ID: T 697/22).

In the referral, the BoA judges cite Article 112(1)(a) of the European Patent Convention. They deem it necessary to harmonise EPC law on the following issues:

If the claims of a European patent are amended during opposition proceedings or opposition-appeal proceedings, and the amendment introduces an inconsistency between the amended claims and the description of the patent, is it necessary, to comply with the requirements of the EPC, to adapt the description to the amended claims so as to remove the inconsistency?
If the first question is answered in the affirmative, which requirement(s) of the EPC necessitate(s) such an adaptation?
Would the answer to questions 1 and 2 be different if the claims of a European patent application are amended during examination proceedings or examination-appeal proceedings, and the amendment introduces an inconsistency between the amended claims and the description of the patent application?
Dispute over green tech patent
The case concerns Knauf Insulation’s EP 2 124 521, which covers a hydroponic growing medium. Knauf manufactures insulation materials primarily used in buildings, including those for green roofs and facades. As global warming concerns mount, the greening of buildings is seen as innovative technology for reducing overheating in buildings and urban areas.

Rockwool, active in the same segment, opposed the grant of Knauf’s EP 521 with support from Meissner Bolte. The Meissner Bolte team includes partner Felix Letzelter, as well as Klaus Linn and former BoA judge Hans-Peter Felgenhauer.

French law firm ARC-IP filed the patent application for Knauf. Aline Sliwa and Guy Farmer from the Belgian firm are handling the appeal proceedings.

EBA must settle contradiction
The BoA judges concluded that Knauf’s auxiliary request claim version is patentable. However, Knauf had not adapted the description, which the Opposition Division had already criticised. Both Knauf and Rockwool appealed the Opposition Division’s decision.

Knauf’s auxiliary requests created a contradiction between the claims and applicable description. Knauf submitted an amended description during appeal proceedings, but the BoA judges rejected this as late. The Enlarged Board must now decide whether these contradictions prevent EP 521’s grant.

Based on previous BoA case law, experts say, the EPO typically requires patent descriptions to align with amended claims. However, whether the European Patent Convention provides grounds for this remains disputed. Some recent BoA decisions have diverged from current case law.