Under the European Patent Convention, apart from the provisions relating to oppositions, once a patent is granted it becomes subject national law and the jurisdiction of the national courts. Consequently, these courts have exclusive jurisdiction over issues of infringement and the interpretation of claims in the infringement context. This can lead to tensions with decisions of the European Patent Office.

Before looking at the two most important cases in this category, however, we should note an infringement decision by the Supreme Court in Germany in the Clinical Trials case[1]. German law, like that of other European countries that have amended their laws to conform with the Community Patent Convention contains a provision taking certain experimental use outside the scope of patent infringement. In the present case, the patent claimed human immune interferon of a defined amino acid sequence free from any other protein with which it is ordinarily associated (gamma interferon). The defendants were carrying out clinical tests to determine whether gamma interferon was useful in treatment of additional conditions beyond those mentioned in the patent. After noting that its previous decision on experimental use in the Ethofumesate case had been decided under previous law and so was not a reliable guide[2] and looking at Dutch and British decisions[3], concluded that in cases where the experiments in question were intended for the purpose of research or to promote technological progress as was the situation in the present case, them the mere fact that there might be some ultimate commercial consequences did not preclude the application of the experimental use exemption.