The prior use defense in patent litigation requires possession of he invention. But how much do you have to know? German Federal Supreme Court (BGH) has issued a decision (BGH Desmopressin X ZR 131/09) addressing this question.
Germany has the reputation of having an easily satisfied possession standard. In Germany, activities that constitute prior use include “use of the invention” and making “substantial arrangements to do the same.” A party asserting the defense must show actual possession of the invention. Possession of the invention means that the asserting party must have recognized the problem and its complete solution according to the invention both objectively and subjectively as well as the possibility to intentionally exploit the invention.
The case at issue in X ZR 131/09 was a utility model relating to a pharmaceutical composition containing an oxidizing agent. Claim 1 required the content of the oxidizing fall short of a certain upper threshold. According to the specification, the low content of oxidizing agent leads to an extended use-by date.
The defendant was able to prove that he had used a recipe inevitably leading to a composition falling under claim 1 but could not prove his subjective knowledge of the relation between the content of the oxidizing agent and the use-by date.
The BGH considered this sufficient. The second headnote reads (in translation):
“The subjective knowledge required for the possession of the invention exists when the activity is methodically directed to the realization of a technical teaching realizing all the features of the subject-matter of the invention (here: a certain recipe of a pharmaceutical composition). It is irrelevant whether or not the acting person has knowledge of effects being related to the realization of the subject-matter of the invention according to the specification (here: that the consideration of an upper limit for the content of oxidizing agent leads to an extended use-by date).”
In the reasons (margin number 18), the court argues that the possession of the invention can not depend on preconditions which did not become part of the technical teaching as defined in the claim. Accordingly, the knowledge of effects mentioned in the specification but not incorporated in the claim may not be decisive for the possession of the invention.