Infringement under the doctrine of equivalents was the main subject of a recent decision of the District Court of The Hague in Bayer Pharma AG v. Sandoz B.V. Bayer owns a European patent which claims a two-step method for the production of the contraceptive drospirenon. This two-step method includes oxidation with a ruthenium salt as catalyst. Drospirenon used to be produced in the prior art in a one-way process. Advantages of the two-step method of Bayer are the facts that more environmental friendly agents are used and that the end product is more pure. Sandoz bought drospirenon from Industriale Chimica s.r.l.(IC) which was located in Italy. IC used the same kind of two-step production process, but TEMPO (2,2,6,6-teramethylpiperidine N‑oxide) was used as a catalyst instead of a ruthenium salt. In Italy this process was considered to infringe the EP patent of Bayer under the doctrine of equivalents. According to the Turin court, the TEMPO catalyst was an equivalent because it was used to perform the same kind of two-step synthesis reaction of drospirenon, involving the same advantages. Hence, the Turin court predominantly considered the essence of the invention, like the old practice of the Dutch courts.

Since in the current Dutch case Sandoz was a party instead of IC, the District Court of the Hague considered itself competent for deciding on this matter again. The Dutch District Court more closely followed Art. 69 EPC and the Protocol on the Interpretation of Art. 69 EPC. According to the description of the Bayer patent, the ruthenium salt performs a “key reaction” which leads to oxidation. No alternatives for the ruthenium salt were mentioned. Since TEMPO belongs to a different chemical class and exhibits a different kind of oxidation reaction mechanism, yielding different side products, the Dutch District Court did not consider TEMPO to achieve the same result in essentially the same way. The function/way/result test failed. It was therefore decided that Sandoz did not infringe the Bayer patent.

Hence, despite the high degree of patent law harmonization, the question of infringement is still not equally decided upon by courts of the different EPC member states. In this case, the Italian court considered the production method of Sandoz (IC) to be equivalent to the patented Bayer process, whereas the Dutch, German, Danish and Swiss courts did not. It is expected that the establishment of the unified patent court will further increase harmonization.