The European Patent Office (EPO) issued its final ruling last week rejecting a much-contested embryonic stem cell patent -- a decision that will likely be cheered by researchers and jeered by biotechs.

The patent covered technology developed by James Thomson, a University of Wisconsin researcher, to culture primate embryonic stem cells derived from pre-implantation embryos. In last week's ruling, the EPO upheld a previous decision, made last summer, that rejected the patent.

Earlier this year the US Patent Office upheld this patent, in addition to two others dealing with derivation and replication of embryonic stem cells in culture. The three patents, filed by the Wisconsin Alumni Research Foundation (WARF) in 1995, were reexamined, beginning in October, 2006, when challenges were brought by the Public Patent Foundation in New York and the Foundation for Taxpayer and Consumer Rights (FTCR) in Los Angeles. The two organizations argued that the patents impede stem cell research, and that other researchers before Thomson had developed the technology.

In a statement from the EPO regarding the current decision, the Enlarged Board of Appeals said that under the European Patent Convention, "it is not possible to grant a patent for an invention which necessarily involves the use and destruction of human embryos."

"I can imagine there will be sighs of relief," Robin Lovell-Badge, head of stem cell biology and developmental genetics at the National Institute for Medical Research, told the Guardian. "There are going to be lots of other biotech companies interested in either applications for the cells or deriving products from the cells, or using the cells in screening methodology."

However, some said the decision could be a setback for biotech companies involved in developing embryonic stem cell technology. The EPO ruling could apply to some 200 other pending patent applications in Europe, PharmaTimes reported.

However, the EPO ruling did state that the decision did not apply in general to the patentability of human stem cells. David Earp, chief patent counsel for Geron -- a stem cell biotech with several pending patent applications in Europe -- told PharaTimes that he his confident the ruling only applies to WARF patents and the agency will move quickly to address Geron's remaining applications.



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