Tough times continue for stem cell patents

Two decisions handed down by a Technical Board of Appeal of the European Patent Office (EPO)—T 1836/10 in April 2013 and T 2221/10 in February 2014—seem to cement the restrictive approach that has taken hold at the EPO with regard to the patenting of human embryonic stem cells (hESCs).

Patenting of hESCs in Europe is largely governed by Article 6(2)(c) of Directive 98/44/EC, the ‘Biotech Directive’, which has been transposed into national law by the EU member states, and Rule 28(c) of the European Patent Convention (EPC), for EPC member states, both of which exclude the use of human embryos for industrial or commercial purposes from patentability.

In the landmark decision G 2/06 (WARF) the Enlarged Board of Appeal of the EPO (EBoA) had to interpret Rule 28(c). The EBoA pointed out that when considering exclusion from patentability under Rule 28(c) one must examine not only the wording of the claims but also the technical teaching of the application as a whole. Applying this interpretation, the EBoA held that any claims directed to products which at the filing date could be prepared exclusively by a method which necessarily involved the destruction of human embryos were excluded from patentability under Rule 28(c). This held even if this method was not part of the claims.

These findings of the WARF decision were subsequently applied by the EPO’s Examining Divisions in an interim practice allowing hESC-related applications under Rule 28(c) if deposited hESC-lines were available on the filing date, without further regard as to whether human embryos had been originally destroyed in their generation. The reason for this was that these inventions did not necessitate the de novo destruction of human embryos on the filing date.

At the EU level, in 2009, the Court of Justice of the European Union (CJEU) was asked to interpret Article 6(2)(c) of the Biotech Directive for a preliminary ruling in the now famous Brüstle case (C-34/10). In comparison to what had been decided in WARF by the EBoA, the CJEU handed down a more restrictive ruling in Brüstle, at least on the face of it, holding that subject matter was excluded from patentability if at any point in time it necessitated the destruction of human embryos or their use as base material.

Although not directly bound by decisions of the CJEU, the EPO adapted its guidelines in the wake of Brüstle, following the CJEU’s restrictive interpretation. Accordingly, the new and more restrictive standard applied by the EPO’s Examining Divisions has led to the interpretation of Rule 28(c) to exclude inventions that necessitate the destruction of human embryos at any point in time prior to the filing date, and also excluding inventions that make use of established hESC lines generated at some point in time by the destruction of human embryos.

Still, it remained questionable whether the boards of appeal of the EPO would follow this standard, as well as how this practice would be reconciled with the EBoA’s decision in WARF.

The answer to this question has been provided in T 2221/10. In this case, the board had to consider the patentability of claims directed to methods for maintaining hESCs. In defence of the pending claims the appellant argued that established hESC lines were available on the filing date, invoking the standard that had been established by the EPO after WARF. The board, however, interpreted the WARF decision to mean that irrespective of the actual availability of these hESC-lines on the filing date the invention was excluded from patentability under Rule 28(c), since it relied on the use of hESC lines which had originally been produced by methods involving the destruction of human embryos.

"Although not directly bound by decisions of the CJEU, the EPO adapted its guidelines in the wake of Brüstle, following the CJEU’s restrictive interpretation."

This decision would leave the applicant with little hope for claiming hESC-related inventions if it were not for new technologies that allow the generation of hESCs without the destruction of human embryos (eg, a method similar to pre-implantation genetic diagnosis, first published in February 2008). Based on this technology, the EPO currently accepts applications directed to hECSs that were filed after this technology had become available. However, it appears that this standard is now called into question again by another appeal board decision.

In T 1836/10, the same board had to consider the patentability of claims directed at methods for the preparation of embryonic stem cells in an embryo-preserving manner, comprising steps isolating the cells from the embryo. Based on the EPO’s previous practice, which was focused on the destruction of human embryos as the sole exclusion criterion, one might expect these claims to be patentable. Far from it, however: the board held that, even when preserving the embryo, a method that uses human embryos as starting material for the preparation of hESCs constitutes a use for industrial or commercial purposes, which is excluded from patentability according to Rule 28(c).

What can be taken from these decisions is the following:

The question that immediately arises is whether in future Rule 28(c) will also be interpreted to exclude inventions that necessitate the non-destructive use of human embryos as a step preceding the claimed invention at some point in time.

In fact, essentially this question has already arisen in another appeal case still pending before the same board (T 1441/13 based on EP 02799217.1). According to a preliminary opinion of the board, attached to the summons, it intends to submit questions concerning this matter to the EBoA, which may already be available for public inspection by the time this article is published.

As a side note, it should be kept be mind that Article 6(c)(2) of the Biotech Directive is once again up for interpretation by the CJEU (C-364/13) in a case concerned with the generation of stem cells from human parthenotes (activated oocytes induced to undergo initial embryogenesis).

Given the EPO’s current restrictive stance on stem cell-related inventions, one may not be too optimistic that a referral to the EBoA in T 1441/13, if accepted by the board, will lead to a more liberal practice in this field.

Franz-Josef Zimmer is a partner at Grünecker. He can be contacted at: zimmer@grunecker.de

Markus Grammel is a patent attorney trainee at Grünecker. He can be contacted at: grammel@grunecker.de