On 25 November 2008 the Enlarged Board of Appeal (EBA) refused Wisconsin Alumni Research Foundation’s (WARF’s) patent application1 deciding that it fell within the exception to patentability under Article 53(a)2 and Rule 28(c) EPC3. Whilst inventions which can only be exploited by the destruction of human embryos were held to be unpatentable, the EBA stressed that this decision does not concern the more general question of human stem cell patentability. The implications of this decision on European patent practice are discussed.


The patent application at issue describes a method by which primate ES cells derived from an embryo can be maintained in vitro for a long period of time without losing their potential to differentiate into any cell of the body. A cell culture comprising primate ES cells was described and claimed. The disclosed method of obtaining the stem cells used, as the starting material, a primate (including human) embryo which was destroyed in the process. The patent application was refused in view of Article 53(a) and Rule 23d(c) EPC (now Rule 28(c) EPC 2000), which prohibits the granting of patents concerning the “use of human embryos for industrial or commercial purposes”. This decision has attracted a wealth of interest worldwide as it concerns moral and philosophical questions about patenting human ES cells.

The Technical Board of Appeal referred four questions to the EBA. The decisions of the EBA are legally binding on the European Patent Office (EPO), including the Examining Divisions, the Opposition Divisions and the Boards of Appeal. The Appellant also sought a referral to the European Court of Justice (ECJ).


The Questions referred to the EBA, and their answers, are as follows:

  1. Does Rule 23d(c) [now 28(c)] EPC apply to an application filed before the entry into force of the rule?This question was answered as ‘yes’.

    This section of the Implementing Regulations reflects the language of the provisions of the European Biotechnology Directive in the European Patent Convention (EPC). Since it was introduced without any transitional provisions, the EBA held that this provision was to be applied as a whole to all then pending applications.

  2. If the answer to question 1 is yes, does Rule 23(d)c [now Rule 28(c)] EPC forbid the patenting of claims directed to products (here: human embryonic stem cell cultures) which – as described in the application – at the filing date could be prepared exclusively by a method which necessarily involved the destruction of the human embryos from which the said products are derived, if the said method is not part of the claims?

    This question was also answered as ‘yes’.

    According to the EBA, the invention concerned inter alia human ES cell cultures which, at the filing date, could be prepared exclusively by a method which necessarily involved the destruction of the human embryos from which they were derived. Although this method did not form part of the claims, the EBA emphasised that Rule 28(c) EPC does not mention claims, but refers to “inventions”. The EBA therefore turned to the technical teaching of the application as a whole in order to assess how the invention was to be performed. Since the only teaching of how to perform the invention to make human ES cell cultures involved the destruction of human embryos it was concluded that the invention fell within the prohibition of Rule 28(c) EPC.

    The Appellant also tried to argue that the use of human embryos to make the claimed human ES cell cultures was not a use “for industrial or commercial purposes”. The EBA concluded that a claimed new and inventive product must first be made before it can be used. Since making the claimed product involved the destruction of human embryos this use was considered to be an integral and essential part of the industrial or commercial exploitation of the claimed invention, which thus violates Rule 28(c) EPC.

  3. If the answer to question 1 or 2 is no, does Article 53(a) EPC forbid patenting such claims? The EBA did not have to answer this question since the answers to questions 1 and 2 were ‘yes’.   
  4. In the context of questions 2 and 3, is it of relevance that after the filing date the same products could be obtained without having to recur to a method necessarily involving the destruction of human embryos (here: eg. derivation from available human embryonic cell lines)?

    This question was answered as ‘no'

    Technical developments, which became publicly available only after the filing date, cannot be taken into consideration.

Referral to the ECJ

The referral to the ECJ was refused for lack of any legal and institutional link between the EPO appeal boards and the EU. Thus it seems that the Enlarged Board of Appeal remains as the highest instance of appeal at the EPO.

Implications on European practice

Inventions concerning the use of human embryos which can only be obtained at the date of filing by means which involve the destruction of human embryos are now unlikely to be considered patentable under the EPC. The wider implications (if any) of this decision are less clear. Whilst it was hoped that the decision might provide guidance on the patentability of human ES cells as such and the use of embryos (and cells/tissues obtained therefrom) it seems that this decision has not done so.

Regarding pending applications relating to human ES cells or products thereof which have been derived from a human embryo, in view of this decision it is possible to conclude that if these types of inventions can only be realised by destroying human embryos then they are unlikely to be considered patentable under the EPC. However, it remains unclear whether an invention which does not necessarily involve the destruction of human embryos will still fall under the scope of this exclusion. If at the date of filing there are disclosed either in the application as filed, or in the prior art, methods which do not require the destruction of human embryos in order to arrive at the claimed invention, it is conceivable that this may be enough to escape the Rule 28(c) EPC exclusion in its entirety. However, the EBA did not comment on this point explicitly.

Therefore, whilst it was hoped that this decision might bring clarity to the interpretation of Article 53(a) and Rule 28(c) EPC, it has only clarified the applicability of this exclusion to certain inventions which have similar facts to the patent application in question.

Exactly how the EPO will interpret this decision and apply it to patent applications in this field remains to be seen. It is likely that opponents attacking third party patents relating to stem cell technology will continue to argue that an invention is not patentable since it encompasses the use of human embryos for commercial or industrial purposes. This may continue to create legal uncertainty for Applicants.

Action from the EPO

This decision has been widely interpreted in the popular press as holding that human ES cells are unpatentable. This is clearly not the case, but the EPO will find itself under intense political pressure from third parties if it starts to grant patents to human stem cells, even if they are not necessarily obtained by the destruction of human embryos. The EPO received over 160 amicus curiae briefs in relation to this appeal alone from lawyers, the biotechnology industry and religious and ethical groups. How the EPO reacts to this remains to be seen; however, we would not expect the EPO to take any decisive action in granting patents to human ES cells in the immediate future. Rather, we would expect the EPO to continue to require the exclusion of human ES cells from the scope of claims in European patent applications, pending further internal and public consultation on this issue.


On a more positive note, it may be possible to work around this exclusion from patentability by using disclaimers. In an earlier EBA decision (G2/03) it was held that disclaimers can be used in Europe where a claim includes non-patentable subject matter – such as inventions which are contrary to “ordre public” or morality under Article 53(a) EPC. Accordingly, the use of a disclaimer which excludes human embryos (or, for example, human ES cells) from the scope of the claim may in certain circumstances be of use in overcoming any objection raised under Article 53(a) and Rule 28(c) EPC. Such a disclaimer does not need to be disclosed in the application as filed. This is because the disclaimer is not considered to relate to the technical teaching of the invention and serves to merely exclude subject matter. This course of action may therefore be acceptable to Applicants who are prepared to exclude human embryos (or stem cells derived therefrom) from the scope of their claims.

National patent offices

For those Applicants seeking to obtain protection for inventions which involve the use of human embryos due consideration should now be given to seeking protection in individual European contracting states. Some contracting states are interpreting the Biotechnology Directive differently to the EPO. For example, the UK Intellectual Property Office currently allows patent applications directed to human pluripotent ES cells (provided they satisfy the normal requirements for patentability) reasoning that they do not have the potential to develop into an entire human body. Human totipotent cells are not patentable. Whether or not national patent offices will alter their practice in view of this decision remains to be seen.

The future

Stem cell research has advanced at a rapid rate and scientists are discovering new sources of material for producing human ES cells. For example, human skin cells treated with a cocktail of transcription factors have been reprogrammed into human ES-like cells without the need for an embryo. Whilst it is still unclear whether or not such a process would be patentable in Europe, it is encouraging to see that this decision was not used to impose a complete ban on human ES cell patenting. Exactly how the EPO implements this decision is awaited with interest.