Retroactive waiver of procedural fees upon joinder of patent nullity suits

The Federal Patent Court (BPatG) ruled that procedural fees previously assessed and paid for multiple separate patent nullity actions remain valid and are not retroactively waived or reduced upon the subsequent joinder of those proceedings, establishing that only fees incurred from the date of the joinder order onward are calculated on a single basis. The dispute concerned the financial consequences of joining several nullity suits under Section 147 of the German Code of Civil Procedure (ZPO), where each initial filing had triggered distinct procedural fees calculated at 4.5 times the statutory rate under the Court Fees Act (GKG) based on individual dispute values. The decisive legal basis is the non-retroactive application of fee regulations upon procedural joinder, confirming that the transition to single-court fees applies prospectively from the joinder decision, leaving the pre-joinder payments intact.