The Technical Board of Appeal Decision No. T923/92 (Genentech, Inc. / The Wellcome Foundation Limited, et al.) is an important decision in the field of biotechnology, in a case relating to human tPA.

In particular, the Technical Board of Appeal confirmed that, in a claim to a protein having a particular amino acid sequence, that sequence is a true technical feature which characterises the invention. It is therefore not possible for such a claim to be entitled to priority from an earlier Application in which the particular amino acid sequence was not disclosed, even if a similar sequence was disclosed in the earlier Application.

This Decision has a broader impact on the general attitude towards the claiming of priority in the European Patent Office. A feature in the claim which forms an essential characterising feature of the invention must be found in the priority-establishing Application for priority to be claimed validly. The primary amino acid sequence of a protein or the nucleotide sequence of a DNA is a true technical feature which characterises an invention and, accordingly, must be in the priority document for priority to be established validly.