In its ruling dated November 27, 2012, the Federal Supreme Court (FSC) finally decided on the well-known Brüstle case. In this case, a nullity action was filed by Greenpeace with respect to a patent of the stem cell researcher Prof. Brüstle. The patent contains claims directed to neural precursor cells derived from embryonic stem cells and methods for producing them.The scope of the claims of the granted patent encompasses neural precursor cells obtained from stem cells produced from the blastocyst stage of human embryos (hES). This latter method is also recited in the description.

The claims do not mention the use of embryos for producing the ES cells. As alternative sources for stem cells, stem cells derived from unfertilized human egg cells, i.e. embryonic germ cells (EGC) and unfertilized eggs in which a cell nucleus from a mature cell has been implanted (“dolly method”) are mentioned.

The nullity action was exclusively based on Section 2 (2) no. 3 German Patent Act which is identical to Art. 6 (2)(c) of the EU Biotech-Directive 98/44 and Rule 28 c) EPC stipulating that no patents shall be granted for inventions directed to the use of human embryos for industrial or commercial purposes. In its decision dated December 5, 2006, the Federal Patent Court decided to maintain the patent with the proviso that the embryonic stem cells are not obtained from human embryos. Prof. Brüstle appealed this decision to the Federal Supreme Court. The Federal Supreme Court referred the case to the Court of Justice of the European Union (CJEU) for a preliminary ruling on the interpretation of the respective provision in the EU Biotech Directive.

In its case C-34/10, the CJEU ruled that the exclusion from patentability is independent from the fact that the prior destruction of human embryos is not contained in the claims if it is required by the technical teaching of the patent. Even if the destruction is not mentioned in the specification at all, the exclusion from patentability can apply. The term “embryo” includes any human egg cell after fertilization, any non-fertilized human egg cell into which either a cell nucleus has been implanted or undergoing parthenogenesis. The CJEU left it for the national court of the member states to determine whether a hES as such represented an embryo. “Industrial or commercial purposes” cover also scientific research, thus the use of human embryos for scientific research cannot avoid the exclusion from patentability.
Applying this ruling to the present case, the FSC reversed the judgment of the Federal Patent Court and maintained the patent with the proviso that the embryonic stem cells are not obtained by destruction of human embryos.

In its reasoning the FSC first construed the scope of the patent as maintained by the Federal Patent Court. This prior judgment does not exclude methods for the production of precursor cells from patentability wherein the embryonic stem cells are produced without the use of an embryo and by avoiding a state of totipotency. The revocation by the Federal Patent Court also does not encompass methods wherein the ES cells are produced from primordial germ cells (also called EGC) which are isolated from several weeks old aborted fetuses. However, the Federal Patent Court excluded from patentability methods wherein ES cells are removed from an embryo independent from the fact whether the embryo is destroyed or not.

The auxiliary request filed on appeal includes the disclaimer “wherein isolated purified precursor cells from human embryonic stem cells produced by destruction of embryos are not encompassed.” This auxiliary request encompasses the possibility that the ES cells are produced from an embryo without its destruction and is therefore broader than the scope of the patent as maintained by the Federal Patent Court.

First, the FSC examined whether the claims according to this auxiliary request are sufficiently disclosed and found that the EGC cells which are defined in the patent as ES cells provide a source for ES cells which is sufficiently disclosed at the filing date and does not require the destruction of embryos.

Second, the FSC examined whether the proposed disclaimer is sufficient to remove methods excluded from patentability from the scope of the claims. The FSC left it open whether possibilities for the production of ES cells from (not arrested) embryos without the destruction thereof are actually available. The Court considered that if such possibilities exist, they are encompassed by the scope of the claim even if not explicitly described in the patent. If said methods should not be available, they cannot lead to an exclusion from patentability. Based on later scientific publications the FSC was convinced that possibilities for the production of ES cells without the destruction of embryos exist.  The FSC referred to the generation of hES cells from so-called arrested embryos which are due to genetic defects impaired in their capacity to divide. According to the decision of the CJEU, an embryo is an organism having the capability to develop into a human being. With regard to these arrested embryos, this capability has been lost without any external factors. The removal of cells from these arrested embryos therefore does not qualify as a use of embryos encompassed by the claim is not excluded from patentability.

Third, the FSC examined whether hES cells represent embryos in the sense of of Sec. 2 para 2 No 3 German Patent Act even if the hES cells were produced without the destruction of embryos and would for this reason alone be excluded from patentability. The FSC decided that hES cells do not possess the capability to develop into a human being (no totipotency). This consideration applies independent from artificial scenarios where an hES cell by combining with further cells may be used to generate an embryo capable of developing into an adult organism. An hES cell is therefore considered not to represent an embryo in the sense of this regulation. Accordingly, hES cell-related inventions are not excluded per se from patentability.

In summary, the FSC decision clarifies that stem-cell related inventions based on non-destructive methods are not excluded from patentability which provides perspectives for applicants in this field. Independent therefrom, the CJEU decision and also the subsequent FSC decision do not question the patentability of ips (induced pluripotency stem cells) cells which have ES-like pluripotency but which are derived from human reprogrammed adult cells.