The European Patent Office (EPO) has developed a standing practice with regard to the enablement requirements (Art. 83 EPC) with regard to claims having parameter features with open-ended range. One of the first decisions has certainly been T 409/91 Exxon laying down the principle that, in order to fulfill the requirement of Art. 83 EPC, the application as filed must contain sufficient information to allow a person skilled in the art, using his common general knowledge, to carry out the invention within the whole area that is claimed.

In this example, the claim required wax crystals having an average particle size less than 4000nm in an auxiliary request, the lower limit (not mentioned in the claim according to main request) has to be set to 1000nm, which actually have been disclosed as an upper limit in original claim 5. Using a disclosed upper limit as a lower limit had been decided to meet the requirements of Art. 123(2) EPC (due support in the original filed documents). In the decision T 1008/02 “Diaper” the Board had to decide on a claim requiring a super absorbent material absorbing “at least 27ml/g of an aqueous solution....”. Also here the Board decided that in view of the fact that there was no upper limit as to the absorption capabilities, the claim had to be rejected under Art. 83 EPC. 

It seems that the principle developed by the EPO is also known in the US, as the Federal circuit, in MAG SIL Corp. w. Hitachi Global Storage tech., Inc. The court affirmed that the asserted claims were invalid as a matter of law for lack of enablement. The court found that the open-ended range recited in the independent claim was not enabled because the disclosure provided support for only a small portion of the claimed open-ended range, citing to the dual function of enablement for both ensuring that there is adequate disclosure to support the claimed invention and preventing claims broader than the disclosed invention. 

The German Supreme Court (BGH) has now decided in March 2019 in X ZR 32/17 on the question of open-ended parameter ranges when applying German national law. The court came to the conclusion that a one side open-ended parameter range is only sufficiently disclosed if the invention is not limited in the disclosure in a specific (limited) range, but thus gives the skilled person a generalized teaching, allowing the skilled person to achieve values going beyond the specific maximum values shown in the patent. So far this decision thus seems to be fully aligned with the principles developed by the Boards of Appeal of the EPO.

In the case to be decided the court denied the enablement of the main request as no generalized teaching could be found in the disclosure of the patent.

While the decision itself is in-line with EPO practice, the solution to the issue may surprise seasoned EPO practitioners….

Where the decision of the Supreme Court actually seems to drastically deviate from the principles developed by the Boards of Appeal of the EPO is the fact that the German Court allowed a main request in which the upper end (initially not defined in the granted claims and in the main request) had now been limited by a specific value mentioned in the context of a specific embodiment, but not disclosed in the originally filed documents as a maximum value of the range in a generalized manner. 

The German court did allow this “isolation” of the maximum value out of the example, without requiring that all remaining essential features of the example to be incorporated in the claim. Most likely a technical Board of Appeal of the EPO would not have allowed such generalization of a feature taught in the specific context of a specific example under Article 123 (2) (sufficient support in the original filed documents). 

Practical Impact:

Therefore, while the decision of the German Court confirmed a comparable approach with regard to lack of enablement, it also stresses the drastically more liberal approach of German national courts (Federal Patent Court, Supreme Court) with regard to the due support of features in the originally filed claims. This stresses the importance of oppositions against European patents based on this formal attack of Article 123 (2), which can be a powerful weapon in EPO proceedings, but which had the potential to be drastically less powerful in national German invalidation proceedings.