In continuation of our articles concerning the patenting of stem cells, we report here on the recent ruling by the Court of Justice of the European Union (CJ) (Case C-364/12) regarding whether human parthenotes fall under the definition of a human embryo under the Biotechnology Directive 98/44.

Biotechnology Directive 98/44

Recital 42 of the Directive states that "human embryos....must be excluded from patentability" whereas Article 6(2) formally states the "use of human embryos for industrial or commercial purposes" as being unpatentable.

International Stem Cell Corporation v Comptroller General of Patents, Designs and Trade Marks

The referral from the UK High Court concerned an appeal brought by International Stem Cell Corporation (ISCC) against a decision made by the UK Intellectual Patent Office (UKIPO) in 2012 to reject two patent applications for a method for inducing pluripotent stem cells from human eggs that have undergone parthenogenesis. The resulting product of this process is referred to as a 'parthenote'.

A parthenote is capable of developing into a blastocyst-like structure but cannot develop into a human being because it lacks paternal DNA. On the evidence before the High Court, human parthenotes were shown to develop to the blastocyst stage over about five days, but after that period the requirement for paternal genes became acute and the oocyte did not develop further, and never to term.

Patenting parthenotes

The legal issue before the CJ was whether parthenotes were excluded from patentability as constituting human embryos as prohibited by Article 6(2)(c) of EU Directive 98/44 and paragraph 3(d) of Schedule A2 to the Patents Act 1977 which implements this Article of the Directive.

The Brüstle ruling involved oocytes that were manipulated by the insertion of a nucleus from a mature human cell. The court's ruling therefore extended the definition of 'human embryo' from an oocyte that had been the subject of fertilisation to one that included instances where fertilisation had not occurred, but by manipulation had been rendered capable of commencing the process of development into a human being just as an embryo created by fertilisation.

ISCO therefore sought to distinguish their case from the previously decided Brüstle ruling in that the patent related to oocytes that had been activated in the absence of sperm, by a variety of chemical and electrical techniques such that the activated oocyte (the parthenote) was capable of dividing and developing, but as presently understood could never develop to term - just to the stage of a five day blastocyst. This technical fact had been supported by all parties who had submitted written observations.

However it was considered that with additional genetic manipulation it could be possible to further develop a parthenote. In acknowledging this possibility the ISCO amended the claims to exclude the use of any further methods being applied to overcome this inability to develop. On this basis the CJ concluded that parthenotes did not fall within the intended scope of 'human embryo'.

Court's further clarification of the term 'human embryo'

The court has therefore used this ruling to further clarify the definition of the term 'human embryo' such that it includes a non-fertilised ovum that has the inherent capacity of developing into a human being but excludes a non-fertilised ovum that does not possess such potential.

Given the understanding of the parthenotes subject of the patent application, the court has left it to the national referring court to reach a final decision as to whether Art 6(2)(c) of Directive 98/44 would not prohibit the UKIPO from granting the patent, ie to reach a decision on the technical facts as to whether a parthenote has "the inherent capacity of developing into a human being".