Following the preliminary ruling of the Court of Justice of the European Union (CJEU; case C-34/10), the long awaited final decision of the German Supreme Court (Bundesgerichtshof, BGH) in the Brüstle case published on January 23, 2013 reveals that a reasonable and relatively broad patent protection on human stem cell-related technology is possible in Germany. The full reasoning makes apparent that, surprisingly, the prior CJEU considerations on this important field of technology were not applied in a narrow and strict manner as could have been expected, and this raises questions on a potential conflict with the present approach taken at the European Patent Office (EPO).

According to a first headnote, the German Supreme Court did not allow an absolute protection on human embryonic stem cells originally obtained from human embryos. However, instead of a general ban the Court according to a second headnote allowed to simply exclude, by way of a disclaimer statement in the claim, cells which can only be obtained by destructing human embryos from which the claimed product is derived. In this respect the German Supreme Court was satisfied that techniques do exist which make it possible to obtain human embryonic stem cells (hESC) without prior destruction of a human embryo.  The court's reasoning is surprising in view of the situation that this was not possible at the filing date of the Brüstle patent at the end of 1997, but rather methods to establish hESCs or corresponding cell lines without destructing a human embryo only became publicly available much later. The Supreme Court apparently found its position to be in line with the CJEU, despite the ruling of the latter that Article 6(2)(c) of the EU Directive 98/44 “excludes an invention from patentability where the technical teaching which is the subject-matter of the patent application requires the prior destruction of human embryos or their use as base material, whatever the stage at which that takes place".

The German Supreme Court also adopted a narrow interpretation of an "embryo", by representing an organism having by itself the capacity of commencing the process of development into a human being. Since this capability of the embryonic stem cells alone got lost during the preparation of the claimed cell preparation, the claimed subject-matter could not be regarded as involving an unpatentable "use of embryos". Importantly, this finding was not changed by the mere possibility that the claimed cells could produce a developable embryo in combination with other cells, as further expressed in a third headnote.

In result the German Supreme Court ensures sensible patent protection in Germany on a critical, yet important field of technology. Germany thus appears to provide more flexible and broader patentability options compared to the present stance at the EPO which appears to adopt a stricter interpretation of the relevant ethical questions on patentability requirements (cf. Enlarged Board of Appeal decision G 2/06; the EPO’s present interpretation of the relevant Rule 28(c) EPC as outlined in the recently amended examination guidelines). The EPO's current approach may have been guided by a presumably restrictive interpretation of biotech patentability provisions in view of just the CJEU's preliminary ruling in the German Brüstle case, and this was seemingly meaningful as the EPO – although not bound by CJEU rulings – should not grant patents which are eventually invalid in its member states based on such restrictive interpretation of the EU biotech directive 98/44/EC. It will now be interesting to see how the EPO will react and possibly modify their current strict approach in view of the flexible and basically patentee-friendly position presently taken by the German Supreme Court. The EPO will soon have a chance to decide on that, as a first instance opposition hearing will take place in April 2013 in relation to the counterpart European “Brüstle patent”, subject to a future clarification by the EPO's Board of Appeal possibly in the next instance.

As long as the EPO’s final position on this issue is not clarified it seems worth considering to file relevant patent applications claiming products covering hESCs and cell lines as national filings, at least in Germany, in view of the presently apparent different – the German Supreme Court's broader and the EPO's more restrictive – interpretations of the corresponding patentability provisions. A further open question is whether other national courts might come to still another interpretation of the EU biotech directive in the field of human stem cells in view of the CJEU ruling.