Drospirenone: A masterclass in equivalents

Case No. S2013_001 ¦ Decision of 21 March 2013 (excerpt) ¦ “Auszug aus dem Urteil Nachahmung (Äquivalenz)”

This post has been updated on 02/15/2016 with a more literal translation of the second question, in light of O2014_002.


Art. 109 PatA; Art. 69 EPC, Protocol on the Interpretation of Article 69 EPC; Art. 66(1) lit. a PatA:

When an allegedly infringing method or device does not literally fulfil one or more features of the claim but comprises replacing features instead, the following three questions need to be answered in the affirmative in order to conclude that the allegedly infringing method or device is within the scope of the claim:

(1.) Does the replacing feature objectively fulfil the same function? (“Gleichwirkung”)

(2.) Was the person skilled in the art enabled to find the replacing feature as having the same effect? Are the replaced features and their objectively same function rendered obvious by the teaching of the patent to the person of skill in the art? (“Auffindbarkeit”)

(3.) With due consideration of the claim wording in view of the description: Would the person skilled in the art have taken the replacing features into account as being an equivalent solution? (“Gleichwertigkeit”) (r. 17.2)

(Non-official translation from German into English language)

We already catched a glimpse of what was going on earlier this year; see the post on ex-parte injunctions of 26 May 2013. Now, we get some deeper insight into the subject-matter at stake. At first, I felt the take-away message is clear-cut: The FPC assess infringement under the doctrine of equivalents using essentially the Schneidmesser questionnaire established in Germany. That’s it. But this would have been too narrowly considered. On closer scrutiny, things are (much) more difficult. In fact, this case might turn out to be a masterclass in assessment of equivalents in various countries.

1.  Background of the case

Drospirenone (DRSP; click to enlarge)

The plaintiff sought for preliminary injunctive relief and invoked two European patents: EP 0 918 791 B3 (hereinafter the ‘791 patent; see the European patent register for further details) and EP 1 149 840 B2 (which is a divisional of the ‘791 patent; hereinafter the ‘840 patent); see the European patent register for further details. Both patents relate to methods for the production of drospirenone (DRSP), a compound used in contraceptives (birth control pills).

Drospirenone closely resembles natural progesterone. Drospirenone-containing pills are presumably the most widely prescribed hormonal contraceptives in the world today. Proprietor of both European patents is Bayer Pharma AG, according to Swissreg (cf. here and here). Drospirenone-containing pills are one of the – if not the – best selling product of Bayer Pharma AG; see some further information directly on the website of Bayer Pharma AG. Thus, it’s reasonable to assume that Bayer Pharma AG or a connected undertaking is the plaintiff. The situation is not that clear to me with respect to the defendant(s), and I am not going to speculate.

2. The decision of the FPC

i)  Ex-parte interim measures

As already outlined in an earlier post, the ex-parte injunction in this case was not granted without any prior hearing of the defendant. In fact, the parties had already presented their case in writing, and a hearing with oral reply and rejoinder had already taken place on 31 January 2013. Moreover, the reporting judge had already presented his preliminary opinion on the merits of the case — presumably essentially in the sense of the present decision. Only shortly thereafter, on 7 February 2013, the plaintiff noticed that not all allegedly infringing products were withheld at the customs but that some appeared on the market in Switzerland. Under these circumstances, the FPC granted an ex-parte injunction.

ii)  Rectification of the record

The record of the hearing is quite lengthy (49 p.), and both parties requested rectifications of the record. The plaintiff did so within three days, pointed to five specific issues and indicated precisely what the correction should be. All these rectifications were accordingly made by the FPC.

The defendant filed his request for rectification only after seventeen days. The FPC held that this request was filed too late and thus already failed for this reason. Moreover, the defendant did not indicate what the correction should be, but rather requested the correction to be made on the basis of the tape. The FPC reminded the parties that the record is to contain the overall content of the submissions, but needs not to be a literal transcript (Art. 235(2) CPC; note that the non-official English translation of the CPC fails to properly recite the German wording “dem wesentlichen Inhalt nach“).

iii)  Value in dispute

The plaintiff had estimated the value in dispute to about CHF 500’000,– and indicated that this is a common value in summary proceedings pertaining to patents in the pharaceutical field. On the other hand, the defendant provided a reasoned estimation of the value in dispute to exceed CHF 1’000’000,– . The FPC agreed with the defendant. “Common values” are irrelevant. What counts is the individual assessment of each case.

iv)  Assessment of equivalents

Here we are at the very core of the dispute. A little bit of chemistry is no longer avoidable. Let’s have a look at the final steps in synthesis of drospirenone (DRSP; click to enlarge):

Final steps in synthesis of drospirenone (DRSP)

The starting molecule is the alkine ZK 34506 which is hydrated to form the compound ZK 92836 (step A). Next, ZK 92836 is oxidised to form the cyclic lactone ZK 90965 (step B). Finally, water is eliminated from ZK 90965 to form the enone DRSP (step C).

In simple terms, claim 1 of EP’791 protects the reaction scheme as outlined above, wherein step B is carried out in the presence of a ruthenium salt as a catalyst. Step C is not specified any further.

On the other hand, the only claim 1 of EP’840 specifically pertains to step C only and requires that dehydration is carried out through addition of p-toluenesulfonic acid.

Apparently, the plaintiff sought for injunctive relief with respect to two different methods. With respect to a “first method”, the FPC held that the plaintiff had not credibly shown that this method is effectively used by the (supplier of the) defendant, in particular in view of the injunction issued with decision 4a O 49/12 – Drospirenon of the Dusseldorf regional court; cf. r. 16. This Dusseldorf decision specifically pertains to the dehydration through addition of p-toluenesulfonic acid and refers to WO 2006/061309 A1 in this respect (more specifically to example 7, relating to a method of manufacturing DRSP that does not rely on a ruthenium salt as catalyst in step B, but still uses p-toluenesulfonic acid in step C). Even the plaintiff seemingly suspected that p-toluenesulfonic acid is not used by the defendant (anymore).

The “second method” is the more interesting one. The defendant did not dispute that the “second method” is used. Apparently, the following features were not literally fulfilled:

  • With respect to EP’791, step B is not carried out in the presence of a ruthenium salt as a catalyst, but rather in the presence of TEMPO in combination with Ca(OCl)2.
  • With respect to EP’840, dehydration is not carried out through addition of p-toluenesulfonic acid, but rather in the presence of pyridine/water.

Assessment of infringement of EP’791

The FPC concluded that both the ruthenium salt on the one hand and TEMPO in combination with Ca(OCl)2 on the other hand objectively fulfil the same function (catalysis), in the absence of any further limitation with respect to the specific mechanism of catalysis in the patent in suit (“Gleichwirkung”). The FPC then briefly discussed whether the person skilled in the art was enabled to find TEMPO in combination with Ca(OCl)2 as having the same effect, but finally left this undecided (“Auffindbarkeit”). Rather, the FPC held that the person skilled in the art would not have taken TEMPO in combination with Ca(OCl)2 into account as being an equivalent solution, with due consideration of the claim wording in view of the description (“Gleichwertigkeit”), for the following reasons: First, EP’791 explicitly aims to replace toxic chromium compounds with catalytic amounts of a metal compound. The ruthenium salt catalyis is said to be the key reaction in EP’791 (cf. para.  [0012]). The FPC thus held that this does not suggest the applicability of an organic radical like TEMPO, and EP’791 is not infringed (r. 17.4-17.8).

Apparently, courts in the Netherlands (Rechtsbank Den Haag, C/09/432919 / KG ZA 12-1391), Germany (Dusseldorf regional court, 4a O 190/12 and 4a O 192/12; both confirmed by the higher regional court with decisions 2 U 26/13 and 2 U 25/13, respectively) and Italy (Corto di Appello di Torino) have also issued decisions on this topic. Of course, the final outcome in main proceedings is to be awaited, but this is where we stand today, to the best of my knowledge:

TEMPO / Ca(OCl)2 replacing a ruthenium salt (EP’791) is held to be …
an infringement in … no infringement in …
IT* x
NL x
CH x
DE x

* From what is discussed in the Dusseldorf decisions, I conclude that the Italian decision relies on an opinion of a court-appointed expert. Unfortunately, I could not yet retrieve a copy of this decision.

Assessment of infringement of EP’840

With p-toluenesulfonic acid, step C of the above reaction scheme is an acid-catalysed elimination of water. On the other hand, pyridine/water is a weakly basic system, relying on a different reaction mechanism. Nevertheless, the result (elimination of water) is the same. The FPC thus held that both reagents fulfill the same function (“Gleichwirkung”). Since both acid- and base-catalysed  elimination reactions are very basic reactions in organic chemistry, the FPC held that the person of skill in the art was enabled to find an appropriate base in general. Moreover, she/he would have also considered pyridine/water in particular since there is a pointer in the introductory part of the patent in suit, i.e. the discussion of the prior art. Therefore, the FPC held that the person of skill in the art was enabled to find pyridine/water as having the same effect (“Auffindbarkeit”). Finally, the FPC held that the person of skill in the art would also have taken pyridine/water into account as an equivalent means, since this reagent is known to her/him (as is evident from the discussion of the prior art in the patent in suit).

Concluding, the FPC held that EP’840 is infringed under the doctrine of equivalents and granted a preliminary injunction.

Again, what’s going on elsewhere? Note that the FPC was aware of the fact that the Rechtsbank Den Haag (C/09/432919 / KG ZA 12-1391) had decided the same question differently (r. 18.3, last para.). Later, the Dusseldorf court in the decisions 4a O 193/12 – Drospirenon II and 4a O 191/12 explicitly took the decision of the FPC into account — and decided for non-infringement. This was confirmed by the Dusseldorf higher regional court in decisions 2 U 23/13 and 2 U 24/13, respectively. To the contrary, the appelate court of Brussels (Belgium) decided for infringement (decision of March 25, 2013 — 2012/KR/127; unfortunately, I could not yet retrieve a copy of this decision). Of course, the final outcome in main proceedings is to be awaited, but this is where we stand today, to the best of my knowledge:

Pyridine/water replacing p-toluenesulfonic acid (EP’840) is held to be …
an infringement in … no infringement in …
NL x
BE x
CH x
DE x

3.  The decision of the Supreme Court

In summary proceedings, the Supreme Court does not examine the case on the merits again. Generally speaking, only violations of the law are reviewed, but not the discretionary adjudication of the first instance. The defendant referred to the decisions of the Dusseldorf regional court; see above. However, this was not considered by the Supreme Court for that it was only lately filed. It would have been interesting to learn more about the Supreme Court’s view on the merits of the case already now, but it’s not much of a surprise that the Supreme Court dismissed the appeal (4A_160/2013).

4.  Remarks

i)  What is not claimed, is disclaimed(?)

Perhaps the best-known statement of the status of the claims in UK law is by Lord Russell of Killowen in Electric and Musical Industries Ltd v Lissen Ltd (1938) 56 RPC 23, 39 (emphasis added):

The function of the claims is to define clearly and with precision the monopoly claimed, so that others may know the exact boundary of the area within which they will be trespassers. Their primary object is to limit and not to extend the monopoly. What is not claimed is disclaimed. The claims must undoubtedly be read as part of the entire document and not as a separate document; but the forbidden field must be found in the language of the claims and not elsewhere.

So, how to deal with the following situation:
The claim requires a feature (A). A variant (B) is outlined in the description of the patent, but not in the claims. Is there any room for equivalency, i.e. to cover embodiments with variant (B) under the doctrine of equivalents?

After the decision Okklusionsvorrichtung of the Federal Supreme Court in Germany, some practitioners feared (and some hoped) that the answer might be a clear “No”. In the meantime, the decision Diglycidylverbindung of the Federal Supreme Court provided some further guidance on the assessment in such cases. In a first step, the specific technical effect of the claimed feature (A) has to be determined in order to differentiate it from the alternative feature (B) mentioned in the description but not included in the claim. Second, it has to be established whether the allegedly infringing means provides for the specific technical effect of the claimed feature (A) and thus differs from the alternative feature (B) mentioned only in the description in the same way as the claimed feature (A).

It will be interesting to read a decision of the FPC in such a situation (in the present matter, the pointer to pyridine/water in the introductory part of EP’840 was apparently not held to preclude equivalency). In an obiter dictum, the FPC seemingly tends to assess such situations in line with the Federal Supreme Court in Germany: It is likely that variants explicitly outlined in the description but not in the claims cannot be considered to be covered under the doctrine of equivalents but rather are waived (r. 17.1, last para.).

Wäre das Mittel nämlich in der Beschreibung aufgeführt, aber nicht im Anspruch, müsste daraus voraussichtlich geschlossen werden, dass der Anmelder auf dessen Beanspruchung verzichtet hat und die betreffende Ausführungsart nicht unter Schutz stellen wollte.

ii)  Questionaires for assessement of equivalents – a broader European picture

In order to assess equivalency, the landmark decision in UK is Improver Corporation v Remington Consumer Products Limited (1990) FSR 181, 189. Questions to be answered in the assessement of equivalency are frequently referred to as Improver questions:

(1) Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no-

(2) Would this (i.e. that the variant had no material effect) have been obvious at the date of the publication of the patent to a reader skilled in the art. If no, the variant is outside the claim. If yes –

(3) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. If yes, the variant is outside the claim. On the other hand, a negative answer to the last question would lead to the conclusion that the patentee was intending the word or phrase to have not a literal but a figurative meaning (the figure being a form of synecdoche or metonymy) denoting a class of things which included the variant and the literal meaning, the latter meaning, the latter being perhaps the most perfect, best-known or striking example of the class.

In Germany, the Federal Supreme Court (BGH) took over a similar schedule of assessment in the decisions Schneidmesser I and Schneidmesser II:

(1) Does the modified embodiment solve the problem underlying the invention by means which have objectively the same technical effect?

(2) Was the person skilled in the art enabled by his expertise on the priority date to find the modified means as having the same effect?

(3) While answering question two, are the considerations that the person skilled in the art applies drawn from the technical teaching of the patent claim (so that the person skilled in the art took the modified embodiment into account as being an equivalent solution)?

And, finally, the test known from the Formstein decision (X ZR 28/85) of the German Federal Supreme Court (a kind of litmus test to preclude that a claim is construed overly broad, i.e. covering prior art):

(4) Is the modified embodiment anticipated or made obvious by the state of the art?

(A more detailed analysis of the doctrine of equivalents in various jurisdictions can be found in Yale Journal of Law and Technology.)

How was this dealt with in Switzerland by now? Well, questions (1) and (2) were already in use (BGE 97 II 85, r. 2; BGE 97 II 85, r. 1; BGE 125 III 29, r. 3b; BGE 115 II 490, r. 2a.), but a third question was missing — until now. However, the present case strikingly shows that similar questionnaires do not necessarily result in similar decisions. Hopefully, there is no revival of Epilady® or Spannschraube on the rise.

Reported by Martin WILMING


Case No. S2013_001 ¦ Decision of 21 March 2013 (excerpt) ¦ “Auszug aus dem Urteil Nachahmung (Äquivalenz)”

(not identified) ./. (not identified)


  • Infringement

Composition of the Board of the FPC:

  • (not identified)

Representative(s) of Plaintiff:

Representative(s) of Defendant:

Full text of the decision right here:

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4 Replies to “Drospirenone: A masterclass in equivalents”

  1. The EP’840 part of this case is the (generalised and illustrative) blueprint for an article of Thomas KÜHNEN, chief judge of the Dusseldorf higher regional court, in GRUR 11/2013 (“Die Reichweite des Verzichtsgedankens in der BGH-Rechtsprechung zum Äquivalenzschutz”). In view of the BGH decisions Okklusionsvorrichtung and Diglycidylverbindung, Mr KÜHNEN raises the question whether mere silence on replacement features might constitute an abandonment of any protection under the doctrine of equivalents for such replacement features — and answers this in the negative.

  2. Just in case you wonder why the EP’840 patent claimed p-toluenesulfonic acid so specifically:

    In fact, claim 1 as initially granted was directed to the use of an acid or Lewis acid for this step. Only in EPO opposition / appeal proceedings, the claim was finally limited to p-toluenesulfonic acid (since no other intermediate generalisation of the acid was given in the application as filed that could have satisfied the “clear and unambiguous” disclosure requirement, I assume); see decision T2505/11 and the DREX of EP’840 B2 with tracked changes over EP’840 B1.

  3. The final judgement in The Netherlands is out. No infringement in both cases. I love the phrase “disclosed but not claimed is disclaimed”. To the best of my knowledge, it’s the first time that the highest court of a non-common-law country applies this pragmatic rule.

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