In patent cases, the issuance of a preliminary injunction (PI) is principally possible, but quite seldom. However, in patent infringement cases, a technical issue has to be assessed, which the court will rarely be able to do in so-called summary proceedings (here, only a preliminary and cursory examination takes place) due to its complexity.
The case law (so far) also assumes this. In principle, it only considers the issuance of a preliminary injunction if both the existence of the patent and the patent infringement are clear. I.e., an erroneous decision to be revised in any subsequent main proceedings must not be seriously to be expected. This is a prognosis decision to be made by the court.
According to case law, as a rule, the legal validity of the injunction patent can only be assumed to be sufficiently secure if the injunction patent has already survived opposition or nullity proceedings in the first instance. Doubts about the legal validity of the injunction patent may already exist if the patent has been challenged by an opposition or nullity action. According to case law, a decision on the validity of the patent may be dispensed with in a few special cases, e.g. in generics cases, if the defendant has already participated in the grant proceedings with his own objections, if the objections to the validity of the injunction patent prove to be groundless even on summary examination, or if the patent is about to expire.
The ECJ emphasized that there is a presumption of validity for European Patents (EP) applied for from the date of publication of their issuance and that they therefore enjoy the full scope of protection of the Enforcement Directive from that date. The practical impact of the ECJ's decision is not yet fully apparent. It can be assumed that the instance courts will not deviate significantly from their previous case law, but rather implement the principles of the ECJ into it.
Depending on the court, the usual duration of preliminary proceedings is much shorter than the main proceeding. The preliminary injunction proceedings are given preferential treatment by the courts.