The European Patent Office (EPO) last week upheld in amended form the last in a series of three cancer gene patents that have been subject to closely-watched opposition proceedings since their grant in 2001.

The three disputed patents cover the human BRCA1 gene as isolated from the human genome, mutations from the gene and its use in the early diagnosis in women of a predisposition to develop breast and ovarian cancer.

After a two-day public hearing, the EPO opposition division, an independent panel made up of three technical members and one legal adviser, on January 25 decided to maintain the final patent in a modified form. The patent covers mutations in the breast and ovarian cancer gene.

The panel ruled that claims covering diagnostic methods had to be removed, restricting the scope of the patent to a defined gene probe for the discovery of a specific mutation in the breast and ovarian cancer susceptibility gene in women.

Greenpeace, one of six opposing parties in the third patent case, called the decision "another important success".

The remaining parties were the French Institut Curie, the Dutch Ministry of Health, the Institut Gustave Roussy, the Belgian Verenigung van Stichtingen Klinische Genetica, and the Assistance Publique of the Parisian hospitals.

"If this decision survives the EPO's ruling in the next instance, a lot has been achieved for the relevant female patients and scientists in Europe," Greenpeace wrote in a statement, referring to a possible appeal of last week's ruling by the patent owners. "The patent owner, US company Myriad, could no longer hinder free access to the illness's diagnosis."

The decision comes a week after the EPO gave a similar ruling on the second patent, which initially included claims to the entire BRCA1 gene. The January 21 decision reduced the patent from about 30 claims to three claims covering specific gene usages – the nucleic probe, the cloning vector and host cells transformed with the vector.

The January decisions were favourable compared with last year's ruling in the first patent case.

In May 2004, the opposition division revoked the first patent, which covered the methods used to facilitate early prediction of a woman's predisposition to cancer by looking at certain mutations in the gene. The EPO ruled that the sequence in the gene covered by a 1994 US patent and claimed as prior art by Myriad was faulty and that any prior art claimed before 1995, when Myriad submitted the corrected gene sequence, was erroneous.

"That's what finally killed the patent," said Siobhan Yeats, director of biotechnology examination and opposition at the EPO.

The patent owners have three months to appeal each ruling following the publication of the EPO's written decision, which can take between two to six months. On January 14 the patent owners, represented by German firm Vossius & Partner, submitted their appeal against last year's first ruling.

On November 26 last year, Myriad Genetics transferred its patent rights to the co-owners, which in the first two patents consist of the University of Utah Research Foundation and the US Department of Health. The third patent is now solely owned by the University of Utah Research Foundation, the Canadian Centre de Recherche du Chul and the Japanese Cancer Institute.

Find out here about the third disputed patent (EP0705903).
Find out here about the second disputed patent (EP0705902).
Find out here about the first patent, decided on last year (EP0699754).
Find out more on each patent, such as written decisions and appeals (available in first patent case), by typing in their publication number here.

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