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The EPO and the WARF stem cell patent

The EPO will not grant patents for human embryo stem cells that require the destruction of the embryo.

According to the provisions of Art 53(1) EPC, "European patents shall not be granted in respect of inventions the commercial exploitation of which would be contrary to “ordre public” or morality, provided that the exploitation shall not be deemed to be so contrary merely because it is prohibited by law or regulation in some or all of the Contracting States".

The Wisconsin Alumni Research Foundation (WARF) European patent application no. 96903521.1 was rejected by the Examining Division as being not patentable pursuant to Art 53 EPC. In this application, an independent product claim was directed to a cell culture of stem cells (i.e., a final product). The Examining Division refused the application, because a pre-implantation embryo that was destroyed in the process of generating the stem cells is the only source of stem cells identified in the application.

The applicant appealed the decision. In view of the importance of this issue, the Board of Appeal referred several questions to the highest judicial body at the EPO – the Enlarged Board of Appeal.

The decision of the Enlarged Board of Appeal
i) Applicability of Rule 28(c) EPC
New Rule 28 EPC lists several inventions for which the EPO will not grant patents. Rule 28(c) EPC specifies that no patents shall be granted for inventions concerning uses of human embryos for industrial or commercial purposes.

The new rule was incorporated into the EPC during the prosecution of that application before the EPO. The question was whether the new rule applied to the present case.

The Enlarged Board decided that Rule 28(c) did indeed apply. The introduction of Rule 28(c) EPC did not disrupt a legal continuum, as there was no indication that the commercial exploitation of human embryos was ever regarded as patentable. Accordingly, it was decided that Rule 28(c) applies to all pending applications, even those that had been filed before that rule came into force.

ii) Effect of Rule 28(c) EPC on a claim related to an end product
The applicant defended the patentability of the claims with the argument that the claims were directed toward cell lines and not to the embryos themselves.

The Enlarged Board considered that Rule 28(c) refers to the invention and not to the claims in the context of its exploitation. Therefore, it considered it necessary to examine not just the claims but rather the technical teaching of the patent application as a whole so as to establish how the invention is carried out. When considered as a whole, it is evident that before the claimed cell culture can be used, it has to be made. The patent application specified that a human embryo was necessarily destroyed in the process of generating the claimed culture. Accordingly, it was decided that a claim directed to a cell culture which may only be obtained by destroying the human embryo (at the filing date) is not allowable. It was further considered that it was irrelevant whether at a later date a technique may be developed by means of which a claimed cell line can be produced without destroying the human embryo.

The EPO subsequently refused the WARF application. By doing so, the EPO diverges from the practice at the USPTO, where WARF obtained three issued patents on human stem cells.

The decision of the Enlarged Board of Appeal made clear that the EPO will not grant patents for human embryo stem cells that require the destruction of the embryo. Although the decision does not expressly state that commercial uses where the embryo is not destroyed are not allowed, it is likely that claims involving such use will also be refused. The wording of Rule 28(c) applies to all industrial or commercial uses of human embryos – not only those uses where the embryo is destroyed.

Since the rule refers solely to human embryos, it is likely that inventions based on stem cell cultures that are initiated from a deposited cell line will be considered allowable. Stem cells that are artificially induced from adult cells (Induced Pluropotent Stem cells
or iPS) will probably also be allowable.

It is noted that in the rationale of this decision it was taken into account that neither the EU legislator, nor the EPC legislator have defined the term “embryo” in terms of its age.