12.6.5 Amendment of the patent
The obligation to allow owners to limit their patents, at least in the case of European patents validated in Spain, was imposed by Article 138(2) of the EPC, as revised in 2000. Under that provision, the owner of a European patent has the right to amend and limit the patent’s claims during proceedings on its validity.
Given the absence of any domestic provision on this point, no such right was recognized for national patents; nor were there any procedural rules for the amendment of European patents validated in Spain. Court rulings were therefore initially left to each judge’s discretion in such cases.
That omission was only partly corrected by the patent law now in force.
12.6.5.1 Patent amendments in judicial proceedings
Patents can be amended during the course of either invalidation or infringement proceedings.
In the case of invalidation proceedings, the patent owner can opt, on a principal or subsidiary basis, to limit the patent by amending its claims.
In this scenario, the owner needs to present and justify a new set of claims to serve as the basis for further proceedings. The plaintiff seeking invalidation must then adjust their arguments so as to either maintain or revise their request for invalidation in light of the limitation proposed.
As explained in Section 12.5.3 in more detail, requests for invalidation of a patent, entirely or partially, are also a typical defense against actions for patent infringement.
The defendant may question the validity of the patent by means of an exception, to have the action simply dismissed, or by filing a counterclaim to have the patent explicitly declared invalid. When such an exception is invoked, the patent owner may request that it be treated as a counterclaim.
If the defendant responds, on either a principal or subsidiary basis, by invoking invalidity, the patent owner can then opt to limit the patent by amending its claims – bringing and justifying a new set of claims in response to the counterclaim (or invalidity defense, as the case may be). The owner must also explain, and possibly prove, how the proposed limitations affect the infringement action.
In the light of a patent amendment made in response to either a counterclaim or a defense, it is then up to the petitioner for invalidation to maintain or amend their petition in light of the proposed limitation.
12.6.5.2 Effect on the proceedings of patent amendment outside the process
A patent under litigation for infringement or invalidity can also be amended outside the process. This may happen when the patent owner applies to the SPTO for an amendment; when an opposition or limitation procedure or an appeal is filed, in the case of national patents; or when procedures are filed before the EPO, in the case of European patents. Amendments may also be made in proceedings before another court.
When a patent is amended outside the process in response to changed circumstances, the patent owner may request that the amended version serve as the basis for court proceedings, which can significantly alter the course of those proceedings.
Spanish procedural rules on this point remain limited, with article 120(4) of LP-2015 providing simply that the judge or court must entertain allegations from the other parties, which can create a range of problems, in particular, the need for both the plaintiff and the defendant to provide new expert evidence analyzing the amendments to the patent, as well as the possibility for the parties to dispute such new evidence. The problem is exacerbated by the fact that this amendment is not limited in time to the initial phase of the proceeding, and may therefore occur at a late stage of the process.