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4 November 2013Biotechnology

New frontiers: potential barriers to patenting induced totipotent stem cell technology

It has for some years been possible to create pluripotent stem cells (stem cells capable of differentiating into many, but not all, other cell types of the body) from fully differentiated adult cells (so called ‘induced pluripotent stem cells’ [iPS cells]).

Recent advances by the tumour suppression group of Centro Nacional de Investigaciones Oncológicas (CNIO) in Spain have resulted in the production of iPS cells with totipotency features, raising the hope that induced totipotent stem cell (iTS cell) technology could become a practical reality. Previous to this discovery, the only practical source of totipotent stem cells (stem cells capable of differentiating into any other cell type of the body) was embryonic tissue.

The possibility of producing iTS cells from adult cells could abolish the current need to use embryos to obtain totipotent cells, thereby removing many ethical concerns associated with this field of research, and perhaps allow the engineering of recipient-derived tissues that are insusceptible to transplant rejection. Hence, it is important to be able to secure patent protection for iTS cell technologies in order to attract the investment necessary to develop them into mature, practical tools.

The widely reported Court of Justice of the European Union (CJEU) decision C-34/10 (commonly referred to as the Brüstle decision) shed light on the patentability of human embryonic stem cells in the EU. As is normal practice, a preliminary opinion on the issues to be decided by the CJEU was published by an attorney general (AG) of the CJEU in advance of the Brüstle hearing. This preliminary opinion included totipotent stem cells in the definition of ‘human embryos’.

If followed by the CJEU, this would have meant that, even if the technology to induce totipotency in adult cells were to be realised, it would been considered an unpatentable ‘commercial exploitation of a human embryo’ in the EU. As totipotent embryonic stem cells would also be caught by the same exclusion, the AG’s approach would have resulted in a blanket ban on patenting totipotent stem cell technology.

Fortunately, the CJEU’s decision did not follow the AG’s preliminary opinion in this regard and totipotent stem cells were not included in the CJEU’s definition of an embryo. However, despite the CJEU’s welcome departure from the AG’s preliminary opinion, a number of potential hurdles remain to patenting totipotent stem cells technologies in the EU.

Various stages of human formation

Although the CJEU’s judgment in the Brüstle decision was that totipotent cells are not included in the definition of an embryo, current UK Intellectual Property Office (UKIPO) guidance states that:

“Human totipotent cells have the potential to develop into the entire human body. In view of this potential, such cells are not patentable because the human body at various stages of its formation and development is excluded from patentability…”

This provision relates to Recital 42 of EU directive 98/44/EC (commonly referred to as the ‘Biotech Directive’) and so is part of the national law of all EU states. Hence, if followed by the UK and other patent offices, the interpretation of totipotent stem cells as a human body at a particular stage of formation would prohibit the patenting of induced totipotent stem cells per se.

What is more, UKIPO guidance also states that:

“Similarly, a method of culturing or propagating human totipotent cells is also excluded from patentability as a claim to a method also provides protection for the product of such a method.”

This provision appears to relate to the fact that, under the European Patent Convention (EPC) and in EPC-contracting states, a claim to a process also provides protection for the direct product of that process. The UKIPO appears to consider that, since the direct product of a process for producing totipotent cells is totipotent cells, and totipotent cells are excluded from patentability by the Biotech Directive, then processes for making them must also be excluded.

There appear to be reasonable arguments against this view.

“The first interpretation allows the creation of totipotent stem cells without the use of embryos and so, if anything, appears to contribute towards human dignity.”

Patent protection for a direct product of a process is provided under the EPC even if that product is not novel (ie, a novel process is still novel in the EU if it can be used to create a non-novel product). Hence, it appears that the direct product of a process is not to be taken into account for assessing the patentability of a claim to that process. Arguably, there is no reason that this principle should be applied to a patentability requirement as fundamental as novelty, yet not to be applied for other requirements.

Chimeras from germ cells or totipotent cells of humans and animals

The Biotech Directive states that:

“… processes, the use of which offend against human dignity, such as processes to produce chimeras from germ cells or totipotent cells of humans and animals, are obviously also excluded from patentability.”

This provision applies to all EU states. It is also noted in the European Patent Office’s (EPO’s) examination guidelines and is commonly understood by commentators to exclude from patentability processes for producing totipotent cells of humans or animals. The language used in the Biotech Directive is, however, ambiguous. The exclusion could refer to:

1. processes to produce:
a) chimeras from germ cells; and
b) totipotent cells of humans or animals. Alternatively, the exclusion could refer to:

2. processes to produce:
a) chimeras from germ cells; and
b) chimeras from totipotent cells of humans or animals.

It does not appear that the exclusion could refer to both interpretations (1) and (2). To determine which interpretation was intended, it must be asked, ‘which of the above interpretations most offends human dignity?’.

The first interpretation allows the creation of totipotent stem cells without the use of embryos and so, if anything, appears to contribute towards human dignity. In contrast, the second interpretation leads to the ‘humanity’ of germ line or totipotent cells being lost, at least in part. Hence, in our view, it appears that the second interpretation was intended.

If the first interpretation was, nevertheless, maintained by patent offices, it would become even more crucial to obtain patent protection for the direct and indirect products of processes for producing totipotent cells (ie, to protect totipotent cells per se).

However, novelty cannot be conferred to a product by the process by which it was produced—a product must be novel in its own right. Hence, there is a risk that, if iTS cells are essentially identical to naturally-occurring totipotent cells (which is likely to be an ultimate scientific and commercial goal), they will be unpatentable through lack of novelty.

Advice to applicants

Although perhaps commercially and scientifically less desirable, it could be beneficial to establish and define in patent specifications multiple embodiments, some being potentially identical to innate totipotent cells but others specifically describing and highlighting clear differences between iTS cells and innate totipotent cells. Such embodiments would appear to provide the opportunity to escape the above-discussed exclusions to patentability in the event that argumentation against them fails.

Andrew Sanderson is senior associate at Potter Clarkson. He can be contacted at: Andrew.sanderson@potterclarkson.com.

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