The patentability of inventions relating to human embryonic stem cells (hESCs) has long been subject to uncertainty. A new potential change of practice at the European Patent Office (EPO) has come to light with recent examination reports suggesting (contrary to the EPO’s previous position) that applications relating to hESCs filed prior to February 2008 are not excluded from patentability under the morality provisions relating to the use of, and in particular, destruction of human embryos. Instead, the EPO now appears to be accepting that applications relating to hESCs filed subsequent to 5 June 2003 do not contravene the above morality provisions. Furthermore, one particular recent examination report issued by the EPO suggests that that the applicable date may even be earlier than 5 June 2003.

The EU’s Biotech Directive (98/44/EC), implemented as Art 53 and Rule 28 of the EPC, states that an invention the commercial exploitation of which would be contrary to morality, is not patentable. The Directive specifically prohibits the use of human embryos for commercial or industrial purposes.

The EPO’s practice on the patentability of inventions relating to human embryonic stem cells (hESCs), which have in practice been derived from human embryos, is based on case law of the EPO and on judgments of the CJEU. A brief overview of certain key decisions that have shaped the EPO’s practice in this area is set out below:

  • 2008 – The EPO’s Enlarged Board of Appeal decided (G2/06) that claims directed to products, which at the filing date of the application could only be prepared by a method that necessarily involved the destruction of a human embryo, were excluded from patentability. This was held to be the case even if the method was not actually part of the claims.
  • 2011 – Following from this decision, in case C-34/10 (Brüstle v Greenpeace), the CJEU ruled that an invention is excluded from patentability if it requires the prior destruction of human embryos or their use as a base material, at whatever stage that takes place. Accordingly, a claim would be excluded from patentability even if it involves the use of an existing hESC line where the destruction of a human embryo for preparing the existing hESC line occurred a long time before the implementation of the invention. A human embryo was defined as “any human ovum after fertilisation… and any non-fertilised human ovum whose division and further development have been stimulated by parthenogenesis”. 
  • 2014 – Although CJEU rulings are not legally binding on the EPO, the EPO’s Technical Board of Appeal (noting that CJEU rulings are persuasive) in decision T2221/10 followed the CJEU’s ruling and held that inventions which make use of publicly available hESC lines initially obtained by methods involving the destruction of human embryos are excluded from patentability.
  • 2014 – In T1441/13 (as reported in our previous article), the EPO’s Technical Board of Appeal decided that Chung et al. (Cell Stem Cell, February 2008, Vol. 2, pages 113-117) provided the first disclosure of a method of establishing hESC lines without destroying a human embryo on 7 February 2008. Therefore, applications relating to hESC which were filed before this date were excluded from patentability as they would have included, at some point in time, the destruction of a human embryo.

In view of the above decisions, the EPO practice has been to reject applications relating to hESCs filed before 7 February 2008.

As set out above, C-34/10 held that an “embryo” encompasses an ovum subjected to parthenogenesis. Parthenogenesis refers to activation of an oocyte, in the absence of sperm, by chemical and electrical techniques, such that the activated oocyte, or parthenote, is capable of dividing and further developing. However, mammalian parthenotes can never develop to term because of the absence of paternal DNA.

In light of this (and contrary to its earlier ruling) the CJEU in its judgment of case C-364/13 (released on 18 December 2014) held that a parthenote does not constitute a human embryo if, in light of current scientific knowledge, it does not have the inherent capacity of developing into a human being (this being a matter for the national courts to decide). This judgment accordingly established that parthenotes are not necessarily human embryos; and that the use of hESCs derived from parthenotes does not necessarily fall foul of the morality provision.

Judgment C-364/13 does not, however, indicate the date from which the skilled person would have been able to generate hESCs from parthenotes.

WO 2003/046141, published on 5 June 2003, discloses a method of “parthenogenetic activation of a human embryo… to generate the stem cells from which autologous, isogenic cells for transplantation therapy are derived”. Therefore, this publication may be referenced in support of applications relating to hESCs filed after 5 June 2003.

Furthermore, a recent examination report in respect of EP application No.13186524.8 (with an earliest priority date of 24 May 2002) concluded, with reference to the C-364/13 judgment, that the invention was not excluded from patentability under the EPO’s morality provisions. This may suggest that the EPO is prepared to accept that a method for deriving hESCs from parthenotes was available to the skilled person even before 5 June 2003.

This change of practice by the EPO does not appear to have been publicised in the Official Journal of the EPO, or reflected in the changes to the Guidelines. Nevertheless, it is good news for owners of applications with an effective date of 5 June 2003 (and possibly even before this date) which are still pending. Moreover, applicants who have recently received a decision to refuse based on the previous case law and who are within the period for filing an appeal should seek to do so as soon as possible.