In decision C 364/13 ISCO v. Comptroller handed down on 18 December 2014, the Court of Justice of the European Union (CJEU) decided that unfertilised human egg cells stimulated to divide and develop in a manner similar to early-stage development of a fertilised human egg are not excluded from patentability within the EU under the Directive on the Legal Protection of Biotechnological Inventions (Directive 98/44/EC, known as the “Biotech Directive”). This decision has implications for European Patents and applications at the EPO, and for national patents and applications in EU member states.


Biotechnology presents a challenge for patent law, in the need to provide a legal environment which promotes research and innovation in this sector which is of such economic and social importance, whilst taking due account of ethical concerns.

One of the aims of the Biotech Directive was to harmonise the application of provisions for excluding inventions considered to be contrary to ordre public or morality from patentability in the field of biotechnology within the EU. Article 6(2)(c) of the Biotech Directive provides that patents cannot be granted for inventions that relate to uses of human embryos for industrial or commercial purposes. However, the scope of this provision has been unclear.

Decision G 2/06 (Use of embryos/WARF) of the Enlarged Board of Appeal of the EPO related to application of the provisions of the European Patent Convention implementing Article 6(2)(c) of the Biotech Directive. Here, the exclusion was interpreted as preventing the grant of a patent for an invention which necessarily involved the use and destruction of a human embryo at the filing date of the application.

In its 2011 decision in C-34/10 Brüstle v. Greenpeace (Brüstle), the CJEU went further, finding that the provision should be interpreted as excluding from patentability all methods that necessarily involved destruction of a human embryo, whether this was a feature of the claimed invention or an inherent step, and irrespective of when such destruction takes place.

The decision in Brüstle had far-reaching consequences for the patentability of inventions relating to stem cells within the EU; even inventions which made use of long-established stem cell lines were excluded from patentability if at the time of filing the patent application the only way of generating those cell lines would necessarily have required the destruction of a human embryo. The exclusion was held to apply even if no further embryos were destroyed in working the invention.

After these decisions, the EPO adopted a practice of refusing patent applications for inventions relating to human embryonic stem cells which were filed before 10 January 2008, taken to be the earliest recorded date of publication of a method by which human embryonic stem cells could be obtained without destruction of an embryo .

Of relevance to the present ruling, the decision in Brüstle also sought to provide clarity as to what exactly constituted a “human embryo” within the meaning of Article 6(2)(c) of the Biotech Directive. It was decided that “human embryo” should be interpreted broadly, as including “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”.

With regard to parthenogenetically-stimulated human ova (parthenotes), the judgement reasoned that this matter should be excluded from patentability as it is “capable of commencing the process of development of a human being, just as an embryo created by fertilisation of an ovum can do so”. The inclusion of parthenotes in the definition of a “human embryo” was controversial as they are considered by many to be an ethical source of human stem cells, not requiring the destruction of a fertilised human egg.


The present case concerns two GB patent applications by International Stem Cell Corporation (ISCO), which relate to producing human embryonic stem cells from parthenotes, and synthetic corneal tissues produced from such stem cells.

The UKIPO refused both applications on the grounds that they were excluded from patentability under Schedule A2 3(d) of The Patents Act 1977, which implements Article 6(2)(c) of the Biotech Directive, as they related to “human embryos” as defined in Brüstle.

ISCO appealed the decision to refuse the applications on the basis that Brüstle should not be binding as its reasoning for including parthenotes in its definition of a human embryo was flawed, as these cells are not capable of developing into a human being.

Several lines of evidence were presented which demonstrated that parthenotes are incapable of developing to a viable human being due to inherent biological limitations which prevents their development beyond a blastocyst-like stage. By contrast to fertilised eggs, parthenotes do not contain any paternal DNA, which is required for the generation of extra-embryonic tissue necessary for normal embryonic development.

Whilst the Hearing Officer accepted that based on the evidence presented that parthenotes were not capable of ultimately developing into a human being, the decision to refuse the applications was upheld.

The findings of the CJEU in Brüstle were found to be in line with those of the referring court in that case, in that during the initial stages of cell division parthenotes go through the same developmental pathway as a fertilised oocyte. It was noted that the decision of the CJEU focussed on commencing of the process of development into a human, rather than completion of the process.

The Hearing Officer expressed sympathy with the Opinion of the Advocate General in Brüstle, which had suggested the definition of a “human embryo” should be based on capacity to ultimately produce a human being. However, it was noted that the CJEU had not considered this in its decision.

ISCO appealed this decision to the High Court of Justice (England and Wales). They argued that it was unclear as to whether the wording “capable of commencing the process of development of a human being” in the CJEU’s decision in Brüstle was intended to include matter which is capable of commencing a process of development of a human being even if the process cannot be completed so that it is incapable of leading to a human being. It was also noted that the evidence provided to the CJEU in Brüstle suggested that parthenotes did have the potential to develop to a human being.

The High Court decided that a further reference was justified, and referred the question:

“Are unfertilised human ova whose division and further development have been stimulated by parthenogenesis, and which, in contrast to fertilised ova, contain only pluripotent cells and are incapable of developing into human beings, included in the term ‘human embryos’ in Article 6(2)(c) of Directive 98/44?”.

The Opinion of Advocate General Villalón in C 364/13 ISCO v. Comptroller issued in July 2014, and recommended that parthenotes should be excluded from the definition of a “human embryo” in the sense of Article 6(2)(c) of the Biotech Directive.

The Opinion remarked that to be considered a “human embryo” the process of development of a human being should not merely be commenced, but rather the process should be capable of resulting in a human being. It was further noted that genetic manipulation of a parthenote to render it capable of developing into a human being may be possible, and that the CJEU should answer the question referred to it to include such subject-matter in its definition of a “human embryo”.

The CJEU followed the Advocate General in answering the referred question as follows:

“Article 6(2)(c) of [the Biotech Directive] must be interpreted as meaning that an unfertilised human ovum whose division and further development have been stimulated by parthenogenesis does not constitute a ‘human embryo’, within the meaning of that provision, if, in the light of current scientific knowledge, it does not, in itself, have the inherent capacity of developing into a human being, this being a matter for the national court to determine.”


The ruling opens up the possibility of obtaining patent protection for inventions relating to certain types of stem cells within the EU.

The CJEU leaves it to the national courts to decide whether a parthenote has the inherent capacity of developing into a human being, based on the current state of scientific knowledge, affording flexibility as to the application of the ruling in anticipation of advancements in this field.

It should be noted that the ruling provides that certain narrowly-defined subject-matter is not a “human embryo”, rather than providing a clearer definition of what in fact is a “human embryo”. The reasoning does, however, appear to be sympathetic to the position that matter which is not inherently capable of developing to a human being should not be considered to be a “human embryo” within the meaning of Article 6(2)(c) of the Biotech Directive.

Whilst the decision does not overturn the broad exclusion of inventions relating to human stem cells following Brüstle, it can at least be viewed as a positive step for commercialisation of research in this field within the EU, which may in turn promote investment.