The Patentability of Stem Cells - A Look at the UK and US Situations

Article was included in our Winter 2009/10 edition of InsideIP.

This article was writen by Kate Whyte in conjunction with Maryanne Trevisan of Wolf Greenfield.

The European Patent Office (EPO) has confirmed its position regarding the patentability of stem cells in a decision from the Enlarged Board of Appeal (G2/06).

The patent application at the centre of the decision (the “WARF Stem Cell Patent”) relates to cultures comprising primate (including human) embryonic stem cells. The claims of the application are directed to the cultures, however, the only method disclosed in the application for the generation of these cultures requires the dissociation of a pre-implantation embryo.

The Examining Division of the EPO refused the application on the ground that the use of an embryo in this way was equal to industrial use, and therefore contravened Art. 53(a) and Rule 28(c) EPC (formerly Rule 23d(c) EPC), which states:

“European Patents shall not be granted in respect of biotechnology inventions which …concern…..(c) uses of human embryos for industrial or commercial purposes.”

The decision to refuse the application was appealed by the applicant, who submitted that the Examining Division had interpreted Rule 28(c) EPC too broadly, and that the correct interpretation confines the exclusion in Rule 28(c) to uses of human embryos, whilst products resulting from such uses were intended to be omitted from the exclusion.

The Technical Board of Appeal upheld the decision of the Examining Division, and referred four questions to the EBA, stating:

“the Board considers the question of the patentability of human embryonic stem cells….as being an outstandingly important point of law…. The patentability of human embryonic stem cells is a highly critical matter which is passionately debated … A decision on the matter by the EBA will lay basic and reliable ground to the treatment of other cases concerning the patenting of human embryonic stem cells”.

The decision handed down by the EBA confirmed that European patent law forbids the patenting of claims directed to products which, at the filing date of the application, could be prepared exclusively by a method which necessarily involves the destruction of the human embryos from which said products are derived, even if the method is not part of the claims. It also confirmed that it is not relevant that, after the filing date, the same products could be obtained without using a method involving the destruction of human embryos.

Accordingly, any invention which involves the destruction of a human embryo will be excluded from patentability by Rule 28(c).  A patent application which only describes methods for obtaining embryonic stem cells that involve the destruction of a human embryo will not, therefore, be granted by the European Patent Office, even if the claimed subject matter is not directed to the method.

Position in the UK

Following publication of G2/06, the UK Intellectual Property Office has confirmed that patents will not be granted for processes for obtaining stem cells from human embryos, on the basis that uses of human embryos for industrial or commercial purposes are not patentable inventions; but that patents will continue to be granted for inventions involving pluripotent human embryonic stem cells provided they satisfy the normal requirements for patentability, and provided that at the filing date of the patent the invention could be obtained by means other than the destruction of human embryos.

Position in the US

The patenting of stem cells is far less restrictive in the US than in Europe.  Inventions relating to pluripotent, but not totipotent, human embryonic stem cells are patentable in the US, regardless of whether the practice of such inventions involves the destruction of a human embryo.

WARF, for example, has obtained several patents relating to human embryonic stem cells, including patents claiming nearly identical subject matter as that claimed in its rejected EP patent application, discussed above.  The primary reason for WARF’s success before the USPTO and its defeat before the EPO is that US patent law has no morality requirement for patentability.  Thus, that WARF’s claimed invention could only be practiced, at the time of filing, through the destruction of a human embryo was of no consequence under US patent law.

However, although not challenged on morality grounds, three of WARF’s patents, including those that claim primate and human embryonic stem cells, have been challenged on prior art grounds post-grant.  These challenges have taken the form of reexaminations requested by the Public Patent Foundation on behalf of the Foundation for Taxpayer and Consumer Rights, on the grounds that WARF’s claims are anticipated or rendered obvious by what was known in the art at the time of filing.  More specifically, the challengers argued, and the USPTO initially agreed, that human embryonic stem cells were not novel since they had been reported in the prior art, and that it would have been obvious to generate human embryonic stem cells using the prior art methods for generating embryonic stem cells from non-human species.  In response, WARF amended some of its claims, in part, to recite “pluripotent” human embryonic stem cells “derived from a pre-implantation embryo,” and also argued successfully that unpredictability in the stem cell art precluded a reasonable expectation of success that the prior art methods would produce human embryonic stem cells.  The USPTO has issued ex parte reexamination certificates for two of the patents, while the remaining inter partes reexamination is under appeal.

Looking Forward

Stem cell scientists around the world are developing stem cells from a variety of non-embryonic sources.  Human induced pluripotent stem (iPS) cells, for instance, are pluripotent stem cells obtained by genetically reprogramming adult somatic cells such as fibroblasts.   Although iPS cells reportedly share some common genetic and phenotypic profiles with embryonic stem cells, they are not derived from embryos and thus are obtained without the use or destruction of human embryos.  These latter features bode well for patentability in Europe and avoiding some of WARF’s patent rights in the US.

Kate McNamara 27 Apr 2009

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