Munich

In battles worthy of a TV court drama, the European Patent Office (EPO) has slashed the scope of two patents on the breast-cancer gene BRCA1. Mutations in this gene predispose women to some hereditary forms of breast cancer.

The outcome can be seen as a victory for those who use the gene to diagnose cancers, but the rulings also raise an ethical conundrum. The gene's most common mutation — frequent in a single group, the Ashkenazi Jews — remains protected by patents; 33 others do not.

In the 1990s, several research groups raced against each other to find the sequence of BRCA1. Myriad Genetics of Salt Lake City in Utah rushed to file a flurry of patents — three of them in Europe — based on the sequence. Myriad required all tests for the gene to be carried out in its labs in Salt Lake City, prompting opposition from enraged clinical researchers in Europe.

Last May, the EPO revoked in its entirety one of Myriad's three patents. In its rush to secure rights, Myriad had filed its sequence of the normal gene with the US patent office in a rough form. It updated the filed sequence regularly, but the EPO ruled that the correct sequence had been filed only after other scientists had deposited the correct sequence in a public database, making it invalid for patenting (see Nature 429, 329; 2004 ).

Myriad has filed an appeal against this decision. It has also transferred ownership of the European patents to the University of Utah, which is now handling opposition to the other two patents, one covering the gene product itself and the other covering specific mutations.

On 20 January the EPO ruled that the patent on the gene product — whose scope originally included any probe, or nucleotide sequence, that can recognize the gene — should be restricted to just one probe. This probe corresponds to a part of the gene whose sequence was completely correct in an early filing.

A ruling on the third patent came on 25 January. This patent originally covered 34 known mutations of BRCA1, but had been restricted, during negotiations in advance of the hearing, to a single mutation — the most common one, which occurs with highest frequency in Ashkenazi Jews. The hearing supported the patent, overruling objections that finding a common mutation in a known gene is not truly inventive.