04 November 2011

Stem cells can be obtained from both adult and embryonic tissue. However, embryonic tissue is currently the only source of totipotent stem cells (stem cells capable of differentiating into any other cell type of the body and, in principle, into an entire organism). The use of human embryos to obtain such stem cells is controversial. Greenpeace sought revocation of a German patent (in the name of Professor Oliver Brüstle) that concerned embryonic stem cells, on the basis that the European Patent Convention (EPC) (and equivalent national laws, including in Germany) does not allow patents to be granted for inventions that concern the use of human embryos for industrial or commercial purposes. The German court referred the following questions to the CJEU (formerly the ECJ):

  1. What is meant by the term "human embryos"?
    • Does it include all stages of the development of human life, beginning with the fertilisation of the ovum, or must further requirements, such as the attainment of a certain stage of development, be satisfied?
    • Are the following organisms also included:
      • - unfertilised human ova into which a cell nucleus from a mature human cell has been transplanted;
      • - unfertilised human ova whose division and further development have been stimulated by parthenogenesis?
    • Are stem cells obtained from human embryos at the blastocyst stage also included?
  2. What is meant by the expression "uses of embryos for industrial or commercial purposes"? Does it include any commercial exploitation within the meaning of Article 6(1) of the Directive, especially use for the purposes of scientific research? and
  3. Is technical teaching to be considered unpatentable pursuant to Article 6(2)(c) of the Directive even if the use of human embryos does not form part of the technical teaching claimed with the patent, but is a necessary precondition for the application of that teaching:
    • - because the patent concerns a product whose production necessitates the prior destruction of human embryos,
    • - or because the patent concerns a process for which such a product is needed as base material?

In a preliminary opinion earlier this year, Attorney-General Bot (an adviser to the court) defined human embryos as any cell or cell mass capable of forming a human, including totipotent stem cells. The AG also held that the EPC prohibits not only patents for the use of material obtained from human embryos but also material (including stem cell lines) derived from human embryo destruction.


Decision of the Court of Justice of the European Union (CJEU)

The CJEU issued its decision on 18 October 2011, defining a human embryo as:

"any human ovum after fertilisation, any non-fertilised human ovum into which the cell nucleus from a mature human cell has been transplanted, and any non-fertilised human ovum whose division and further development have been stimulated by parthenogenesis".

Notably, this definition excludes totipotent stem cells, leaving the door open for the patenting of technologies based on induced totipotent stem cells, if and when this technology is realised.

The decision also stated that inventions are excluded from patentability if their technical teaching:

"requires the prior destruction of human embryos or their use as base material, whatever the stage at which that takes place and even if the description of the technical teaching claimed does not refer to the use of human embryos". (emphasis added)

The decision confirms that the exclusion covers the use of human embryos for purposes of scientific research. At first sight, this appears to prohibit the patenting of any technology that requires, or ever required, the destruction or use of human embryos. This would presumably mean that all technology requiring the use of embryonic stem cells is unpatentable in the EU.

However, in the exposition of the decision, the court states that the third question referred in essence, asks:

"...whether an invention is unpatentable even though its purpose is not the use of human embryos, where it concerns a product whose production necessitates the prior destruction of human embryos or a process for (sic) which requires a base material obtained by destruction of human embryos". (emphasis added)

This could suggest that the term "their use as a base material" in the decision does not refer to the use of human embryos, but to the use of destroyed human embryos, as a base material. This interpretation is supported by the decision also stating that:

"...it is for the referring court to ascertain, in the light of scientific developments, whether a stem cell obtained from a human embryo at the blastocyst stage constitutes a ‘human embryo' ".

If all embryonic stem cell-derived materials were indeed considered unpatentable, then this statement would be redundant. Hence, it appears that the Biotech Directive might not prohibit technologies that require the use, but not the destruction, of human embryonic stem cells (although this may not be clear until it has been tested in future court cases).

Arguably, technologies developed after it became possible to obtain human embryonic stem cells without the destruction of donor embryos did not require embryo destruction (even if, in practice, embryos were destroyed). Hence, the decision may not affect the validity of existing patent filings that were applied for after a certain date.

The statement that a national court has to decide whether a stem cell taken from a blastocyst is an ‘embryo' is odd, since such cells are only pluripotent, not totipotent, and so cannot lead to a complete human being. It appears to be intended to pre-emptively exclude from patentability future technologies that could allow the development of a human being from pluripotent stem cells.


Advice to clients

The decision relates to the interpretation of existing legislation and no indication is given that the decision is not retroactive, so it appears that it may affect the patentability of both future and existing patent filings. Accordingly, we recommend reviewing any granted or pending European patent filings relating to stem cell technologies to assess their vulnerability to the CJEU ruling (including those of competitors). Although the decision formally affects only the countries of the EU, rather than non-EU EPO countries such as Switzerland, Norway, Iceland and Turkey, the CJEU's decision accords with that of the EPO Enlarged Board of Appeal in the "WARF" case (G2/06).

Clearly the decision must be taken into consideration when drafting patent applications relating to stem cell technologies. It was, and is, usually possible to side-step the bar to patents on methods of medical treatment by drafting the claim carefully. However, in the light of the Brüstle decision, if the invention concerns stem cells, then it is primarily the description that is important. If possible, worked (or at least theoretical) examples should be included to show that the invention does not require the prior destruction of human embryos. Such examples could include a description of how to acquire human embryonic stem cells without destroying the donor embryo (see for example Klimanskaya et al., 2006, Nature, 444:481-485), the use of adult or induced stem cells, or (perhaps) the use of human-animal cytoplasmic hybrids and the like (which do not require the destruction of fertilised human ova).

Please contact Dr Andrew Sanderson or anyone else in our biotechnology department if you would like further information on this topic.

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