The claim wording is decisive for the scope of protection of a patent. However, the description must also be taken into account, both for the technical meaning of the claim wording and for determining the scope of equivalence. According to a now established principle, embodiments which are disclosed in the description but which no longer fall within the wording of the claim may not be regarded as protected equivalents. What is the situation with undisclosed but obvious variants?

The dispute revolved around Eli Lilly’s Patents EP 1 313 508 B1. To explain the technological background, the patent specification mentions that antifolates are among the best-studied classes of antineoplastic agents. Five substances are given as examples of known antifolates, including pemetrexed disodium. However, antifolates are highly toxic and have therefore been combined with vitamin A, which reduces toxicity. According to the originally filed patent claim, the invention was to be seen in the combination of a methylmalonic acid-reducing substance with an antifolate.

In the course of the Examination Proceedings, however, the broad claim was limited to the combination of pemetrexed disodium (as an antifolate) and vitamin B12 (as a methylmalonic acid reducing substance) for inhibiting the growth of tumors. The patent specification made no reference to pemetrexed dipotassium.

Shortly before the IP Right expired, a generics manufacturer informed the patent holder that it intended to market a combination drug of vitamin B12 with pemetrexeddicalium after the IP Right expired.

The patent holder then filed a Lawsuit against the generics manufacturer for equivalent patent infringement. The Regional Court upheld the Lawsuit. On appeal, however, the Düsseldorf Higher Regional Court denied the patent infringement. The patent specification consistently referred to pemetrexed disodium (Alimta®) as the effective antifolate. The chemical definition was precise and unambiguous. The patent specification does not give any indication that pemetrexed disodium is to be understood as something other than the specifically stated active ingredient. The skilled person’s knowledge that it is the antifolate effect of pemetrexed disodium and not the pemetrexed disodium itself that is important cannot lead to other pemetrexed substances falling within the scope of protection. The discrepancy between the description text and the granted patent claim reflects the course of the Examination Proceedings. It was unacceptable that subject-matter of the invention, which the Application had deliberately abandoned in the Examination Proceedings, should subsequently be re-included in the patent protection via the legal concept of equivalence in the infringement proceedings. It could make no difference whether the alternative solution variants were listed in a detailed list or whether – as in the patent in suit – they were designated as it were collectively by a superordinate generic term.

The Federal Court of Justice (BGH) overturns the ruling of the Düsseldorf Higher Regional Court and refers the case back for further assessment.

It is true that, according to the judgment “Okklusionsvorrichtung”(X ZR 16/09), the scope of equivalence in the case of a selection decision cannot be extended to an embodiment which is disclosed or in any case discoverable by a person skilled in the art, but which the reader of the patent specification must assume – for whatever reason – should not be protected. However, this principle only applies to the constellation that the patent specification itself discloses several possible embodiments and that the patent proprietor has thus made a selection decision. However, an extension to every embodiment that could be found on the basis of the information in the patent specification would go too far. Findability is a basic requirement for the affirmation of equivalence. It cannot be used in the third cutting blade question to exclude equivalence.

The OLG wrongly assumes that the disclosure of a genus of chemical compounds has the same legal effects as the listing of all compounds belonging to the genus and already known as such on the priority date. In the case in dispute, pemetrexed dipotassium is not explicitly named in the patent application. The fact that it is an antifolate and belongs to the same group as pemetrexed disodium is, according to jurisprudence, not sufficient for it to be regarded as disclosed by the specification of the patent in suit(“Olanzapin” – X ZR 89/07; “Escitalopram” – Xa ZR 130/07). Special circumstances which could indicate that the skilled person nevertheless reads this compound have not been established. The case is therefore referred back for further fact-finding.

Note: With this judgment, the BGH clarifies the question of how to proceed if the embodiment sued for infringement falls under a generic term mentioned in the patent specification, but is not expressly mentioned among the examples of the generic term. In this case, equivalence is possible in principle.

The assessment of whether a modified embodiment is to be classified as an equivalent patent infringement or not is still difficult because not only the wording of the patent claim but also other circumstances must be taken into account. The Federal Supreme Court is aware of this and also states this in the judgment: “The consequence of taking equivalents into account is that it is not possible for the public to assess the scope of protection of a patent precisely and conclusively in every respect on the basis of the wording of the claim alone. However, this is an acceptable part of the balance between the patent proprietor’s interest in adequate protection and the public’s interest in sufficient legal certainty.