On 24 and 25 June 2008, in a public hearing on Wisconsin Alumni Research Foundation (WARF) Stem Cell patent application (G-02/06), the European Patent Office (EPO) took the usual step of asking the public to assist it in making a determination regarding a patent application involving an invention in the controversial area of stem cell patenting.


In a patent application for the so-called WARF Stem Cell Patent, relating to a preparation of primate (including human) embryonic stem cells, the EPO arranged for public oral proceedings on 24 and 25 June 2008 before the Enlarged Board of Appeal. The hearing concerned an appeal against the rejection of European Patent application No. 0770125 under the title “Primate embryonic stem cells” filed by WARF in 1995. The patent application described a method by which primate embryonic stem 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.

On 13 July 2004, an EPO Examining Division refused to grant a patent for the WARF application on the grounds that it was contrary to the European Patent Convention (EPC), citing as one of its central reasons that the disclosed method of obtaining stem cells used as the starting material a primate (including human) embryo that was destroyed in the process. According to the patent examiner, this contravened the provisions of the EPC and EU Directive 98/44/EC for the legal protection of Biotechnological inventions (the Biotechnology Directive) which imposes an obligation on the EPO to ensure that no European patents shall be granted for inventions concerning uses of human embryos for industrial or commercial purposes. In other words, the patent examiner stated that, as it involved stem cells that could conceivably include human stem cells, the patent was against the morality clause of the EPC.

APPEAL AND REFERENCE WARF subsequently appealed the examiner’s decision. In 2005, the Technical Board of Appeal of the EPO referred a number of points of law to the EPO’s Enlarged Board of Appeal to clarify certain open legal points regarding the patentability of human embryonic stem cells under the EPC. In order for the Enlarged Board to make a proper assessment of the science and the moral implications it invited comments from the President of the EPO, the patent applicant and the public at large.

The questions for debate were

  1. Does [Rule 28(c)] EPC apply to an application filed before the entry into force of the rule (i.e., the Biotechnology Directive)?
  2. If the answer to question 1 is yes, does [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?
  3. If the answer to question 1 or 2 is no, does Article 53(a) EPC forbid patenting such claims?
  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: e.g. derivation from available human embryonic cell lines)?


Unfortunately, a decision was not handed down on the day, but is going to be delivered as a reference document to allow the Technical Board of Appeal to then properly assess the WARF patent application in view of the EPC and Biotechnology Directive. It therefore remains to be determined whether the patent application covers viable subject matter capable of patentability.