Stem Cell Inventions: EPO Follows Brüstle CJEU Decision

The original procedure for the isolation of human embryonic stem cells (hESC) involves the destruction of a blastocyst, a very early pre-implantation stage embryo consisting of approximately 150 cells. However, alternative technologies are now available.

Established human embryonic stem cell lines have been developed, which are a suitable starting point for many hESC-related inventions. The deposit of such hESC lines by the Israel Institute of Technology (Technicon) at the US National Institutes of Health (NIH) in May 2003 has been considered to mark the start of the period where such cell lines were ‘available’ (see below).

In August 2006, the US-based company Advanced Cell Technology (ACT) published findings relating to a method for extracting embryonic stem cells without destroying the actual embryo, deriving a stem cell line using a process similar to preimplantation genetic diagnosis, in which a single blastomere is extracted from a blastocyst.

Then in about 2007, induced pluripotent stem (iPS) cell technology was developed in which adult cells are reprogrammed to an embryonic-like state.

Rule 28(c) of the European Patent Convention (EPC) states that European patents shall not be granted in respect of biotechnological inventions which concern “uses of human embryos for industrial or commercial purposes”.

Prior to the Brüstle decision, an unofficial interim practice had arisen at the EPO whereby patent applications filed after May 2003 were generally considered to escape the Rule 28(c) exemption on the grounds that, as deposited human embryonic stem cells lines were available, it was not necessary to destroy a human embryo as part of the practice of the claimed invention.

However, the Brüstle decision indicated that the use of hESC lines as a starting point is not sufficient to escape the exemption as the cell lines themselves have involved destruction of a human embryo in their preparation. The fact that this may have happened a long time before the implementation of the invention was considered to be irrelevant.

The EPO Guidelines now read as follows (Part G, Chapter II Paragraph 5.3 (iii)):

A claim directed to a product, which at the filing date of the application could be exclusively obtained by a method which necessarily involved the destruction of human embryos from which the said product is derived, is excluded from patentability under Rule 28(c), even if said method is not part of the claim (see G 2/06). The point in time at which such destruction takes place is irrelevant.

When examining subject matter relating to human embryonic stem cells under Art 53(a) and Rule 28(c), the following has to be taken into account:

(a) The entire teaching of the application, not only the claim category and wording, and

(b) The relevant disclosure in the description in order to establish whether products such as stem cell cultures are obtained exclusively by the use, involving the destruction, of a human embryo or not. For this purpose, the disclosure of the description has to be considered in view of the state of the art at the date of filing.

This wording suggests that the EPO is planning to revise its previous practice. Patentees will no longer be able to rely on the May 2003 date for availablilty of hESC lines. Instead it seems likely that a new date will be settled upon at which it is considered that alternative technologies were available to produce hESCs which did not involve the destruction of a human embryo.

We will have to wait and see whether the date relates to the availability of ACT’s method, iPS cells, or some other stem-cell related technological advance.

It is also not clear, considering (a) and (b) above, the extent to which the use of the new technology would need to be exemplified in the application as filed. It may be that one will need to show that the invention has been put into practice using stem cells made by a method which does not involve the destruction of a human embryo. On the other hand, it may be possible to argue that such cells were available at the time of the invention and could have been used instead of hESC or hESC lines in order to practice the invention.