At what stage should a defendant challenge a patent’s validity?

The most common defence against patent violation is to challenge the partial or total validity of the patent at issue by filing an objection or counterclaim. The basis of these nullity actions is most often lack of novelty and, especially, inventive step.

Where a patent owner requests a preliminary injunction against the defendant, it must demonstrate that it has the right to make such a request. The probability of the alleged claim (fumus boni iuris) is based chiefly on the fact that the patent owner is the rightful owner and the patent valid, and also on the submission of proof substantiating the alleged patent violation. Logically, defendants that intend to argue that the patent is invalid should make this allegation at the proceeding for a preliminary injunction as well as at the main proceedings, in order to try to destroy the appearance of the plaintiff’s rights.

When to challenge
Various courts take different approaches to main proceedings and proceedings for preliminary injunctions, meaning that defendants are advised to raise the issue in the latter type of proceeding. According to Article 728.2 of the Civil Procedure Act, a ruling on the grounds of a request for a preliminary injunction must be “provisional and circumstantial” and, most importantly, must take place “without prejudging the background of the matter”. This being the case, is it possible to strip a patent of legal effect without a previous, firm decision on its validity?

Most legal decisions issued on this matter have tended to deal with patent validity challenges in proceedings for a preliminary injunction. However, some decisions have ruled against the possibility of evaluating a patent’s validity, even at a circumstantial level, as happened in a decision issued by Section Three of the Provincial Court of Murcia on 26th January 2005. Others, such as two decisions issued by Provincial Court of Barcelona, have given preference to the patent owner’s rights over the possible validity action, without expressly excluding this possibility.

Section 15 of the Provincial Court of Barcelona ruled in this respect in its decisions of 4th January 2006 and 22nd February 2007, which state that:

“Within the narrow procedural framework which involves evaluation of the requirement of the appearance of right for the preliminary injunctions the Court cannot judge the validity of said patent in full, but rather circumstantially, in which the registration of the patent in favor of the moving party is decisive.”

More recently, on 5th December 2008 Commercial Court No 5 of Madrid clarified the scope of the defendant’s allegation of patent nullity. This decision is important because it expressly recognised the defendant’s right to invoke the invalidation of the moving party’s patent at a proceeding for a preliminary injunction. The defendant sought support from Article 126 of the Patent Law, which allows defendants to allege total or partial nullity in all types of proceedings.

The decision points out that if the patent does not pass the validity test, then the plaintiff cannot benefit from the appearance of right. However, as a proceeding for a preliminary injunction is provisional and circumstantial, the validity of the registered patent should prevail over its possible nullity. This assumes that “the exception of the invoked nullity should enter into play only when the nullity is considered sufficiently reasonable”. In light of these circumstances, the Madrid court concluded that:

“Tt is possible to examine the possible nullity of the patent as a criterion that could lessen the appearance of right, but this analysis ought to be made cautiously so as not to leave the owner of the industrial property rights unprotected... to prevent the right of industrial property from remaining void of content when an action is exercised for the protection of same, when the nullity of the patent is invoked, the existence for nullity should remain reasonably clear so that the appearance of right may be affected.”

Other factors to consider
It seems clear that a defendant should be able to question the plaintiff’s rights by claiming that the disputed patent lacks validity. Previous decisions on this subject suggest that the owner’s right of exclusivity over the patent (ius prohibendi) is compromised only where the patent’s nullity is clear from evidence provided by the defendant.

The matter might be resolved if judges took into consideration the examination procedure undergone by the patent before being granted. Clearly a domestic patent which has gone through the general procedure set out in Article 30 of the Spanish Patent Law does not have the same weight as a domestic patent granted under the prior examination procedure or of a European patent granted by the European Patent Office.

In these last cases, examinations carried out by independent specialists should reinforce the appearance of the patent owners’ right and limit the likelihood of any allegation of invalidity succeeding. If the state of art being called into question by the defendant was considered by the patent office when granting the patent, the court should give preference to the patent’s right and leave the nullity analysis for the main proceeding.