Mind your language

The German Federal Court of Justice (FCJ) considered the infringement of a Swiss-type medical use claim under the doctrine of equivalents for the first time in the June decision of X ZR 29/15 (Pemetrexed).

The FCJ used this opportunity to clarify its previous decisions of Okklusionsvorrichtung and Diglycidverbindung, which have been widely perceived as significantly reducing the scope of protection of a patent under the doctrine of equivalents in Germany. Some litigators even have considered these decisions to be the final nail in the coffin of the doctrine of equivalents for Germany.

On the one hand, the present Pemetrexed decision limits the applicability of the restrictive Okklusionsvorrichtung and Diglycidverbindung decisions; on the other hand, however, in contrast to current practice, the FCJ seems to be willing to take into account a patent’s file-wrapper (electronic file) in the future.

The doctrine allows a court to hold a party liable for patent infringement if the infringing device or process is equivalent to the claimed invention rather than falling within the patent’s literal scope.

In the Pemetrexed case, Eli Lilly (plaintiff) is the owner of the German part of a European patent which is concerned with the use of pemetrexed disodium in combination with vitamin B12 for inhibiting tumour growth. Independent claim 1 of the asserted patent is a Swiss-type claim that reads: “Use of pemetrexed disodium in the manufacture of a medicament for use in the combination therapy for inhibiting tumour growth in mammals wherein said medicament is to be administered in combination with vitamin B12 or a pharmaceutical derivative thereof.”

Swiss-type claims were previously used in European practice at the European Patent Office to cover the medical use of a compound or composition and to sidestep the prohibition of claims directed to methods of treatment.

Actavis (defendant) had informed Eli Lilly that it intended to market a generic pharmaceutical with the active ingredient pemetrexed dipotassium before the patent expired, using Eli Lilly’s originator product Alimta as a reference pharmaceutical. Eli Lilly filed suit in Germany requesting injunctive relief. The Regional Court of Düsseldorf granted relief based on infringement under the doctrine of equivalents. On appeal, the Higher Regional Court of Düsseldorf repealed the Regional Court’s decision and denied infringement under the doctrine of equivalents. Eli Lilly then appealed this decision to the FCJ.

Three steps

German courts assess infringement under the doctrine of equivalents applying a three-step test consisting of three questions, which are commonly referred to as the Schneidmesser questions. These questions have been defined by the FCJ in the fundamental Schneidmesser I (Cutting Blade I) decision (X ZR 168/00):

1. Does the variant solve the problem underlying the claimed invention with a substitute element that objectively attains the same technical effect?
2. At the priority date was the skilled person in the position to find the substitute element as attaining the same technical effect without practising inventive skill?
3. Are the considerations that the skilled person applies to identify the substitute element in line with the technical teaching of the claimed invention in such a way that the skilled person considers the variant as an equivalent solution to the problem of the invention?

If all three questions can be answered affirmatively, the variant with the substitute element can be generally considered to infringe the patent under the doctrine of equivalents.

In particular, the third question often causes trouble and has received a lot of attention in recent years. In general, it serves the purpose of providing an appropriate scope of protection by taking into account the inventor’s contribution to the art and ensuring legal certainty for third parties. Both aspects necessitate that the technical teaching of the claims not only forms the starting point but the very foundation for the determination of the scope of protection.

It is therefore not sufficient if the skilled person can identify the substitute element as attaining essentially the same effect without practising inventive skill.

In addition, the considerations leading to the identification must also be in line with the technical teaching of the patent claim: they must be oriented towards the claim, as the FCJ says.

Selection principle

In the Schneidmesser decisions the FCJ formulated the general principle that, if the patent objectively falls short of the actual technical content of the invention, the scope of protection under the doctrine of equivalents has to be limited to what is in line with the claimed invention. It expressed the idea that in principle the patentee shall not gain protection for something that was not included in the claim—intentionally or unintentionally—to protect the interests of third parties based on legitimate expectation.

In Okklusionsvorrichtung, the FCJ further defined this principle. In this case, the description of the patent mentioned multiple elements that could be used to attain a certain technical effect. We refer to these elements as A, B, C and D, but the asserted claim recited only one of these elements, namely A. The accused infringing variant did not have element A, recited in the claim, but employed substitute element B.

According to the FCJ, because the description discloses multiple elements A, B, C and D that may be used to attain a certain technical effect, but the claim recited only one element, namely A, this constituted a selection by the patentee. This selection has to be taken into account when answering the question of whether the skilled person’s considerations are in line with the technical teaching of the claim (third Schneidmesser-question).

In general, the FCJ held that if the description discloses multiple ways of how a technical effect can be attained, but only one way is included in the claim, the use of the other ways generally does not constitute an infringement under the doctrine of equivalents. That is because the reader of the patent in such a situation must presume that the patent is not intended to protect an embodiment that is disclosed in the description but not included in the claim (here elements B, C and D).

In the later case, Diglycidverbindung, the situation was slightly different. The description of the asserted patent mentioned two elements that could be used to attain a particular effect, A and B. Again, the claim recited only one of these elements (A), constituting a selection under Okklusionsvorrichtung. In contrast to Okklusionsvorrichtung, the accused embodiment made use of a substitute element C, which was not mentioned in the patent.

In Diglycidverbindung, the FCJ generally affirmed the principles established in Okklusionsvorrichtung. Diglycidverbindung adds that in case of substitute elements that are not mentioned in the description, to be in line with the patent claim under the third Schneidmesser question, the substitute element (C) of the variant must differ from the elements disclosed in the description but not included in the claim (B) in a similar manner as the recited element (A) differs from them.

This requirement essentially also excludes substitute elements from protection which are not mentioned in the description in the sense of Okklusionsvorrichtung, but which by their nature are closer to the elements exclusively mentioned in the description than to the recited means of the claim.

Following these two decisions, practitioners were left with the impression that any mention or suggestion of alternative or modified ways of solving the underlying problem of the invention in the patent that was not covered by the literal meaning of the claims—previously considered helpful for arguing for an infringement under the doctrine of equivalents—now turned against the patentee and precluded infringement under the doctrine.

Limits to the selection principle

The facts of Pemetrexed are different again from Okklusionsvorrichtung and Diglycidverbindung. The asserted patent claim recites the disodium salt of pemetrexed. The substitute element of the accused embodiment is the dipotassium salt of pemetrexed (compared to the disodium salt recited in the claim). However, in contrast to Okklusionsvorrichtung and Diglycidverbindung the asserted patent in Pemetrexed does not mention any other specific alternatives than the explicitly recited disodium salt of pemetrexed.

In particular, the patent does not mention the substitute element pemetrexed dipotassium. Instead, the description only refers to the general class of antifolates, to which pemetrexed and the different salts of pemetrexed, such as the claimed disodium salt and the attacked dipotassium salt, belong (this was also common general knowledge).

The Higher Regional Court of Düsseldorf was of the opinion that the disclosure of the genus antifolates has the same legal consequences as individually listing all species belonging to the genus, consequently invoking a selection according to Okklusionsvorrichtung. The FCJ in its decision, however, rejects this interpretation with reference to its established jurisprudence on the concept of disclosure (according to Okklusionsvorrichtung, elements “disclosed” in the description but not included in the claims are excluded from the scope of protection).

In particular, the FCJ refers to its previous decisions of Olanzapin (X ZR 89/07) and Escitalopram (Xa ZR 130/07), in which it essentially held that a generic term or formula does not disclose all individual compounds that fall under the generic term or formula and that as a rule a compound can only be considered disclosed if it is individualised. The FCJ therefore finds that the genus antifolates mentioned in the patent does not disclose the substitute element pemetrexed dipotassium and, consequently, the principles of Okklusionsvorrichtung do not apply in the present case.

Furthermore, the FCJ holds that the mere fact that the substitute element is obvious over the patent is not sufficient to apply the principles of Okklusionsvorrichtung.

Despite the clear statement that a selection cannot be argued based on the Okklusionsvorrichtung principles in such a genus v species situation, the FCJ leaves a loophole by pointing out that this does not completely eliminate the possibility of a selection invention per se. Importantly, the patent or any other circumstances that may be used for claim construction (see file-wrapper estoppel below) may still allow the conclusion that a selection has been made. This would have to be determined on a case by case basis.

In principle, however, and for the sake of simplicity, the following picture emerges as a general rule, which we have summarised in Table 1.

Table 1: General rules emerging from Pemetrexed and previous decisions

File-wrapper estoppel

It used to be established German jurisprudence that the file-wrapper of a patent may not be used to interpret a claim and determine the scope of protection. It is generally considered that the grant of a patent (or the maintenance in amended form following opposition proceedings) separates the administrative proceedings at the patent office from the judicial infringement proceedings, and that the former does not spill over into the latter.

However, in Okklusionsvorrichtung the FCJ mentioned in an obiter dictum the possibility to consider the published patent application or earlier versions of the granted patent (eg, before limitation in opposition proceedings) for claim construction.

The FCJ in an obiter dictum in Pemetrexed goes at least one step further. The court discusses that under certain circumstances the limitation of the claims during the proceedings (seemingly referring to the grant proceedings as well as potential opposition and revocation proceedings) may constitute a selection. The court is of the opinion that a selection may be generally affirmed if the claim has been limited to avoid prior art—whether it was objectively necessary or not.

In contrast, if the claim scope has been narrowed to overcome formal objections, eg, clarity or added matter, typically there is no selection. Moreover, the FCJ holds that statements of the applicant as well as the examiner during examination proceedings may be considered in infringement proceedings as evidence of the skilled persons understanding of the invention.

In the context of contributory infringement, Pemetrexed also clarifies that Swiss-type medical use claims are purpose-limited product claims by nature. With this claim construction the court continues its jurisprudence of earlier decisions in which it was already stated that the use of a compound for the treatment of a disease, irrespective of the specific claim wording, ultimately concerns an inherent feature of the compound. In effect, under German jurisprudence, a medical use claim, irrespective of the specific wording (eg, second medical use claim according to article 54(5) EPC or Swiss-type), is considered to have purpose-limited product claim character.

This now stands in contrast to the case law, for example, at the European Patent Office, where in decisions T1780/12 and T1673/11 the competent technical boards considered a Swiss-type claim to be a purpose-limited process claim that is different in scope from a second medical use claim (a purpose-limited product claim) according to Article 54(5) EPC.

The Pemetrexed decision touches on numerous points of great relevance for pharmaceutical patent litigation and beyond. It confirms that in principle a different compound can be considered a valid substitute means under the doctrine of equivalents. It essentially limits the applicability of the earlier Okklusionsvorrichtung decision to cases where the substitute means is explicitly mentioned in the asserted patent, thereby strengthening the doctrine of equivalents.

However, on the other hand it also further opens the door for a file-wrapper estoppel in Germany. Therefore, patent applicants and patentees are certainly well advised to keep in mind that any statements during prosecution or any amendments of the claims may later be held against them.

Bernd Allekotte is an attorney-at-law and partner at Grünecker. He can be contacted at:  allekotte@grunecker.de

Markus Grammel is a patent attorney and associate at Grünecker. He can be contacted at:  grammel@grunecker.de